research on water treatment

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Recent advancements in water treatment

For immediate release, acs news service weekly presspac: january 19, 2022.

Generating clean, safe water is becoming increasingly difficult. Water sources themselves can be contaminated, but in addition, some purification methods can cause unintended harmful byproducts to form. And not all treatment processes are created equal with regard to their ability to remove impurities or pollutants. Below are some recent papers published in ACS journals that report insights into how well water treatment methods work and the quality of the resulting water. Reporters can request free access to these papers by emailing  newsroom@acs.org .

“Drivers of Disinfection Byproduct Cytotoxicity in U.S. Drinking Water: Should Other DBPs Be Considered for Regulation?” Environmental Science & Technology Dec.15, 2021

In this paper, researchers surveyed both conventional and advanced disinfection processes in the U.S., testing the quality of their drinking waters. Treatment plants with advanced removal technologies, such as activated carbon, formed fewer types and lower levels of harmful disinfection byproducts (known as DBPs) in their water. Based on the prevalence and cytotoxicity of haloacetonitriles and iodoacetic acids within some of the treated waters, the researchers recommend that these two groups be considered when forming future water quality regulations.

“Complete System to Generate Clean Water from a Contaminated Water Body by a Handmade Flower-like Light Absorber” ACS Omega Dec. 9, 2021 As a step toward a low-cost water purification technology, researchers crocheted a coated black yarn into a flower-like pattern. When the flower was placed in dirty or salty water, the water wicked up the yarn. Sunlight caused the water to evaporate, leaving the contaminants in the yarn, and a clean vapor condensed and was collected. People in rural locations could easily make this material for desalination or cleaning polluted water, the researchers say.

“Data Analytics Determines Co-occurrence of Odorants in Raw Water and Evaluates Drinking Water Treatment Removal Strategies” Environmental Science & Technology Dec. 2, 2021

Sometimes drinking water smells foul or “off,” even after treatment. In this first-of-its-kind study, researchers identified the major odorants in raw water. They also report that treatment plants using a combination of ozonation and activated carbon remove more of the odor compounds responsible for the stink compared to a conventional process. However, both methods generated some odorants not originally present in the water.

“Self-Powered Water Flow-Triggered Piezocatalytic Generation of Reactive Oxygen Species for Water Purification in Simulated Water Drainage” ACS ES&T Engineering Nov. 23, 2021

Here, researchers harvested energy from the movement of water to break down chemical contaminants. As microscopic sheets of molybdenum disulfide (MoS2) swirled inside a spiral tube filled with dirty water, the MoS2 particles generated electric charges. The charges reacted with water and created reactive oxygen species, which decomposed pollutant compounds, including benzotriazole and antibiotics. The researchers say these self-powered catalysts are a “green” energy resource for water purification.

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Environmental Science: Water Research & Technology

Innovation for sustainable water

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Environmental Science: Water Research & Technology  is a Transformative Journal, and Plan S compliant

Impact factor: 5.0*

Time to first decision (all decisions): 14.0 days**

Time to first decision (peer reviewed only): 52.0 days***

Editor-in-Chief: Graham Gagnon

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Meet the team

Read our latest themed issues Urban stormwater management Data-intensive water systems management and operation Polymers in liquid formulations Drinking water oxidation and disinfection processes

Journal scope

Environmental Science: Water Research & Technology  seeks to showcase high quality research about fundamental science, innovative technologies, and management practices that promote sustainable water.

The journal aims to provide a comprehensive and relevant forum that unites the diverse communities and disciplines conducting water research relevant to engineered systems and the built environment. This includes fundamental science geared toward understanding physical, chemical, and biological phenomena in these systems as well as applied research focused on the development and optimisation of engineered treatment, management, and supply strategies.

Papers must report a significant advance in the theory, fundamental understanding, practice or application of water research, management, engineering or technology, within the following areas:

• Treatment and fate of chemical and microbial contaminants, including emerging contaminants
• Water distribution and wastewater collection
• Green infrastructure
• Stormwater management and treatment
• Potable reuse
• Residue management
• Sustainability analysis and design, including life cycle assessment studies
• Municipal and industrial wastewater treatment and resource recovery
• Drinking water treatment
• Water policy and regulation
• Applications of new water technologies* 
• Water, sanitation and hygiene (WASH)
• Water-energy nexus
• Simulation and data science applications to engineered water systems
• Environmental remediation of soil, sediment, and groundwater
• Impacts of climate change on engineered water systems

The journal places special focus on issues associated with water sustainability, as well as research that may lead to more secure, resilient and reliable water supplies. And it welcomes inter- and multidisciplinary work contributing to any of the above developments that are likely to be of interest to the broad community that the Journal addresses.

Manuscripts should be written to be accessible to scientists and engineers in all disciplines associated with the Journal.

All manuscripts must highlight their novel features and explain the significance of the work relative to related studies in their field as well as the likely impact on relevant water communities in the industry, government or academia.

*Please see the below expandable section for specific guidance regarding this area of our scope.

Measurement advances and analysis: these papers are encouraged and must clearly focus on the relevance of the work to engineered water systems and clearly explain the implications of the analysis or observations for sustainable water management. Papers dealing only with analysis, analytical method development or that simply report measured concentrations of target analytes (for example, occurrence and effluent concentrations of novel pollutant classes) will not be considered for publication.

Modeling: papers that lack appropriate validation through either experimental data or available and reliable datasets will not be considered for publication.

New materials or technologies for water treatment: emphasis must be placed on one of the following:

• Developing a fundamental understanding of the underlying mechanisms integral to technology performance
• Demonstrating how the practical application of the technology advances the field and improves upon existing treatment options

Papers in this area are strongly discouraged from focusing solely on technology demonstrations in model systems with model pollutant targets. Rather, they are encouraged to consider performance in complex (that is, environmentally relevant) systems and performance metrics (for example, efficacy across multiple pollutant targets, longevity, regeneration during application, and sustainability assessment) most relevant to real world application. 

Technology papers: we will not consider papers that focus solely on any of the following:

• Heavily focused on material synthesis and characterisation (such as nanomaterial catalysts)
• Consider only the removal of highly idealised targets (such as dyes)
• Work exclusively in clean laboratory systems
• Do not demonstrate innovation that advances the treatment field, or develops a technology without a clear and viable pathway to full scale implementation

Sustainability assessments: papers that cover, for example, life cycle assessment or life cycle cost analysis, of water-related technologies and systems must emphasize the fundamental insight into the factors governing technology or system performance. Papers are strongly discouraged from solely reporting absolute or comparative assessments of technologies/systems without uncovering novel insight or identifying critical barriers to sustainability.

These guidelines will be used by our Associate editors and reviewers to assess the significance of each submitted manuscript.

See who's on the team

Meet Environmental Science: Water Research & Technology  Editor-in-Chief and board members.

Editor-in-chief

Graham Gagnon , Dalhousie University, Canada

Associate editors

Sebastià Puig Broch , Universitat de Girona, Spain

Wenhai Chu , Tongji University, China

Ning Dai , University at Buffalo, USA

Lauren Stadler , Rice University, USA

Liu Ye , The University of Queensland, Australia

Editorial board members

Takahiro Fujioka , Nagasaki University, Japan

Karin Jönsson , Lund University, Sweden

Branko Kerkez , University of Michigan, USA

Jeonghwan Kim , Inha University, South Korea

Linda Lawton , Robert Gordon University, UK

Luca Vezzaro , Technical University of Denmark, Denmark

Eveline Volcke , Ghent University, Belgium

Federico Aulenta , National Research Council, Italy

Nicholas Ashbolt , University of Alberta, Canada

Tom Bond , University of Surrey, UK

Joby Boxall , The University of Sheffield, UK

Kartik Chandran , Columbia University in the City of New York, USA

Amy Childress , University of Southern California, USA

David Cwiertny , University of Iowa  

Joel Ducoste , North Carolina State University, USA

Marc Edwards , Virginia Tech, USA

Jingyun Fang , Sun Yat-sen University, China

Maria Jose Farre , Catalan Institute for Water Research, Spain

Yujie Feng , Harbin Institute of Technology, China

Kathrin Fenner , Swiss Federal Institute of Aquatic Science and Technology, Eawag, Switzerland 

Ramesh Goel , University of Utah, USA

Ola Gomaa , National Center for Radiation Research and Technology, Egypt

Chris Gordon , University of Ghana, Ghana

April Gu , Cornell University, USA

Jochen Hack , TU Darmstadt, Germany

Zhen "Jason" He , Washington University in St. Louis, USA

Xia Huang , Tsinghua University, China

Cynthia Joll , Curtin University, Australia

Tamar Kohn , École Polytechnique Fédérale de Lausanne, EPFL, Switzerland

Peng Liang , Tsinghua University, China

Irene Lo , Hong Kong University of Science and Technology, Hong Kong

Julie Minton , WateReuse Foundation, USA

Vincenzo Naddeo , University of Salerno, Italy

Indumathi M Nambi , Indian Institute of Technology Madras, India

Long Ngheim , University of Technology Sydney, Australia

Paige Novak , University of Minnesota, USA

Yong Sik Ok , Korea University, South Korea

Ligy Philip , Indian Institute of Technology Madras, India

Thalappil Pradeep , Indian Institute of Technology Madras, India

Zhiyong "Jason" Ren , Princeton University, USA

Peter Robertson , Queen's University Belfast, UK

Michael Templeton , Imperial College London, UK

Kai Udert , Swiss Federal Institute of Aquatic Science and Technology, Switzerland

Subramanyan Vasudevan , CSIR-Central Electrochemical Research Institute, India

Xin Wang , Nankai University, China

David Weissbrodt , TU Delft, The Netherlands

Krista Wigginton , University of Michigan, USA

Di Wu , Ghent University, South Korea

Defeng Xing , Harbin Institute of Technology, China

Jeyong Yoon , Seoul National University, South Korea

Neil Scriven , Executive Editor

Grace Thoburn , Deputy Editor

Nour Tanbouza , Development Editor

Claire Darby , Editorial Production Manager, ORCID 0000-0003-3059-6020

Emma Carlisle,  Publishing Editor

Hannah Hamilton , Publishing Editor

Ephraim Otumudia , Publishing Editor

Irene Sanchez Molina Santos , Publishing Editor

Michael Spencelayh , Publishing Editor

Callum Woof , Publishing Editor

Lauren Yarrow-Wright , Publishing Editor

Kate Bandoo , Editorial Assistant

Linda Warncke , Publishing Assistant

Sam Keltie , Publisher, Journals, ORCID 0000-0002-9369-8414

Article types

Environmental Science: Water Research & Technology publishes:

Communications

Full papers, perspectives, critical reviews, frontier reviews, tutorial reviews, comments and replies.

Reviews & Perspectives are normally invited, however suggestions for timely Reviews are very welcome. Interested authors should contact the Editorial Office at [email protected] with an abstract or brief synopsis of their intended Review.

These must report preliminary research findings that are novel and original, of immediate interest and are likely to have a high impact on the Environmental Science: Water Research & Technology community. Authors must provide a short paragraph explaining why their work justifies rapid publication as a communication.

Original research papers on any of the subjects outlined in the scope section and related areas are encouraged and welcomed. All papers should give due attention to overcoming limitations and to underlying principles. All contributions will be judged on the following four criteria. 1. Novelty and insight 2. Quality of scientific work and content 3. Clarity of objectives and aims of the work 4. Appropriateness of length to content of new science

These may be articles providing a personal view of part of one discipline associated with Environmental Science: Water Research & Technology or a philosophical look at a topic of relevance. Alternatively, Perspectives may be historical articles covering a particular subject area or the development of particular legislation, technologies, methodologies or other subjects within the scope of the journal.

Critical reviews must be a critical evaluation of the existing state of knowledge on a particular facet of water research or water technologies as they affect environmental science. They should be timely and provide insights based on existing literature. They should be of general interest to the journal's wide readership.

All Critical reviews undergo a rigorous and full peer review procedure, in the same way as regular research papers. Authors are encouraged to identify areas in the field where further developments are imminent or of urgent need, and any areas that may be of significance to the community in general. Critical reviews should not contain any unpublished original research.

These are shorter, more focused versions of Critical reviews on a well-defined, specific topic area covering approximately the last two-three years. Articles should cover only the most interesting/significant developments in that specific subject area.

The article should be highly critical and selective in referencing published work. One or two paragraphs of speculation about possible future developments may also be appropriate in the conclusion section.

Frontier reviews may also cover techniques/technologies that are too new for a Critical review or may address a subset of technologies available for a given area of research within the journal scope.

Frontier reviews should not contain unpublished original research.

Tutorial reviews should provide an introduction and overview of an important topic of relevance to the journal readership. The topic should be of relevance to both researchers who are new to the field as well as experts and provide a good introduction to the development of a subject, its current state and indications of future directions the field is expected to take. Tutorial reviews should not contain unpublished original research.

Comments and Replies are a medium for the discussion and exchange of scientific opinions between authors and readers concerning material published in Environmental Science: Water Research & Technology.

For publication, a Comment should present an alternative analysis of and/or new insight into the previously published material. Any Reply should further the discussion presented in the original article and the Comment. Comments and Replies that contain any form of personal attack are not suitable for publication. 

Comments that are acceptable for publication will be forwarded to the authors of the work being discussed, and these authors will be given the opportunity to submit a Reply. The Comment and Reply will both be subject to rigorous peer review in consultation with the journal’s Editorial Board where appropriate. The Comment and Reply will be published together.

Journal specific guidelines

See a summary of ESWRT’s journal-specific guidelines . More details are also provided below.

Use of RSC template

There are no submission specifics regarding formatting; use of Royal Society of Chemistry template is not required. Bibliographies should be formatted according to the following Endnote and Zotero style files to include the cited article’s title.

Authors are encouraged to include line numbering in submitted manuscripts. Although there is no page limit for Full papers, appropriateness of length to content of new science will be taken into consideration by reviewers.

Water Impact Statement

All submitted manuscripts must include a 'Water Impact Statement' (60 words maximum; approximately three sentences) that clearly states in plain language the broad-scale implications and real-world relevance of the work. True potential for immediate real-world impact may be subject to further study, but the pathways towards achieving that impact in future should at least be envisioned and explained.

Read Professor Michael Templeton’s Editorial Perspective “ Achieving real-world impact ” for further discussion on expectations for the journal.

Authors should use this statement to show that they have given serious consideration as to how their work addresses current challenges related to water sustainability in a realistic sense. This statement will be carefully considered by the editors and the reviewers and will help ascertain the relevance of the article for a broad audience. Absence of potential for real-world impact is reason for rejection. If the manuscript is accepted this statement will be included in the published article. Please note that manuscripts without this statement will not be peer-reviewed.

Double-anonymised peer review option

Environmental Science: Water Research & Technology is now offering authors the option of double-anonymised peer review. Both single- and double-anonymised peer review are now available to authors.

• Single-anonymised peer review - where reviewers are anonymous but author names and affiliations are known to reviewers. (This is the traditional peer review model used on Environmental Science: Water Research & Technology)
• Double-anonymised peer review - where authors and reviewers' identities are concealed from each other.

Guidelines for authors and reviewers can be found  here

Organisation of material

An article should have a short, straightforward title directed at the general reader. Lengthy systematic names and complicated and numerous chemical formulae should therefore be avoided where possible. The use of non-standard abbreviations and symbols in a title is not encouraged. Please bear in mind that readers increasingly use search engines to find literature; recognisable, key words should be included in the title where possible, to maximise the impact and discoverability of your work. Brevity in a title, though desirable, should be balanced against its accuracy and usefulness.

The use of series titles and part numbers in titles of papers is discouraged. Instead these can be included as a footnote to the first page together with a reference (reference 1) to the preceding part. When the preceding part has been submitted to a Royal Society of Chemistry journal but is not yet published, the paper reference number should be given.

Author names

Full names for all the authors of an article should be given. To give due acknowledgement to all workers contributing to the work, those who have contributed significantly to the research should be listed as co-authors. Authors who contributed equally can be noted with a Footnote and referenced with a symbol.

On submission of the manuscript, the corresponding author attests to the fact that those named as co-authors have agreed to its submission for publication and accepts the responsibility for having properly included all (and only) co- authors. If there are more than 10 co-authors on the manuscript, the corresponding author should provide a statement to specify the contribution of each co-author. The corresponding author signs a copyright licence on behalf of all the authors.

Table of contents entry

This entry should include a colour image (no larger than 8 cm wide x 4 cm high), and 20-30 words of text that highlight the novel aspects of your work. Graphics should be as clear as possible; simple schematic diagrams or reaction schemes are preferred to ORTEP- style crystal structure depictions and complicated graphs, for example. The graphic used in the table of contents entry need not necessarily appear in the article itself. Authors should bear in mind the final size of any lettering on the graphic. For examples, please see the online version of the journal.

Every paper must be accompanied by a summary (50-250 words) setting out briefly and clearly the main objects and results of the work; it should give the reader a clear idea of what has been achieved. The summary should be essentially independent of the main text; however, names, partial names or linear formulae of compounds may be accompanied by the numbers referring to the corresponding displayed formulae in the body of the text.

Please bear in mind that readers increasingly use search engines to find literature; recognisable, searchable terms and key words should be included in the abstract to enable readers to more effectively find your paper. The abstract should aim to address the following questions.

• What is the problem or research question being addressed?
• What experimental approach was used to address the problem or question?
• What key data and results were obtained?
• What conclusions can be drawn from the experimental results?
• What are the broader implications for the study with respect to water sustainability?

Water Impact Statement 

Authors must provide a 'Water Impact Statement' (60 words maximum) that clearly highlights the broad-scale implications and real-world relevance of the work. This statement should be different from the abstract and must set the work in broader context with regards to water sustainability. True potential for immediate real-world impact may be subject to further study, but the pathways towards achieving that impact in future should at least be envisioned and explained in this statement.

When composing your Water Impact Statement, please consider the following points:

1.What is the problem? 2.Why is it important? 3.How does this translate to real-world applications/scenarios? 4.How can this be generalised?  5.Why is this work significant for ensuring sustainable water resources?  

This statement will be seen by the reviewers and will help ascertain the relevance of the article for a broad but technical audience. Authors should use it to show that they have given serious consideration to the impact of their presented study. Absence of potential for real-world impact is reason for rejection. If the paper is accepted this statement will also be published. Please note that papers cannot be peer-reviewed without this statement.

Introduction

This should give clearly and briefly, with relevant references, both the nature of the problem under investigation and its background.

Descriptions of methods and/or experiments should be given in detail sufficient to enable experienced experimental workers to repeat them. Standard techniques and methods used throughout the work should be stated at the beginning of the section. Apparatus should be described only if it is non-standard; commercially available instruments are referred to by their stock numbers (for example, Perkin-Elmer 457 or Varian HA-100 spectrometers). The accuracy of primary measurements should be stated. In general there is no need to report unsuccessful experiments. Authors are encouraged to make use of electronic supplementary information (ESI) for lengthy synthetic sections. Any unusual hazards inherent in the use of chemicals, procedures or equipment in the investigation should be clearly identified. In cases where a study involves the use of live animals or human subjects, the author should include a statement that all experiments were performed in compliance with the relevant laws and institutional guidelines, and also state the institutional committee(s) that have approved the experiments. They should also include a statement that informed consent was obtained for any experimentation with human subjects. Referees may be asked to comment specifically on any cases in which concerns arise.

Results and discussion

It is usual for the results to be presented first, followed by a discussion of their significance. Only strictly relevant results should be presented and figures, tables, and equations should be used for purposes of clarity and brevity. The use of flow diagrams and reaction schemes is encouraged. Data must not be reproduced in more than one form - for example, in both figures and tables, without good reason.

This is for interpretation and to highlight the novelty and significance of the work. Authors are encouraged to discuss the real world relevance of the work reported and how it promotes water sustainability. The conclusions should not summarise information already present in the text or abstract.

Acknowledgements

Contributors other than co-authors may be acknowledged in a separate paragraph at the end of the paper; acknowledgements should be as brief as possible. All sources of funding should be declared.

Bibliographic references and notes

These should be listed at the end of the manuscript in numerical order. We encourage the citation of primary research over review articles, where appropriate, in order to give credit to those who first reported a finding. Find out more about our commitments to the principles of  San Francisco Declaration on Research Assessment (DORA).

Bibliographic details should be cited in the order: year, volume , page, and must include the article title. For example: Lukas Mustajärvi, Ann-Kristin Eriksson-Wiklund, Elena Gorokhova, Annika Jahnke and Anna Sobek, Transferring mixtures of chemicals from sediment to a bioassay using silicone-based passive sampling and dosing, Environ. Sci.: Processes Impacts , 2017, 19 , 1404-1413. See  Endnote style files . For Zotero, please use the Royal Society of Chemistry (with titles) template.

Bibliographic reference to the source of statements in the text is made by use of superior numerals at the appropriate place (for example, Wittig3). The reference numbers should be cited in the correct sequence through the text (including those in tables and figure captions, numbered according to where the table or figure is designated to appear).  Please do not use Harvard style for references.

The references themselves are given at the end of the final printed text along with any notes. The names and initials of all authors are always given in the reference; they must not be replaced by the phrase et al . This does not prevent some, or all, of the names being mentioned at their first citation in the cursive text; initials are not necessary in the text. Notes or footnotes may be used to present material that, if included in the body of the text, would disrupt the flow of the argument but which is, nevertheless, of importance in qualifying or amplifying the textual material. Footnotes are referred to with the following symbols: †, ‡, §, ¶, ║etc.

Alternatively the information may be included as Notes (end-notes) to appear in the Notes/references section of the manuscript. Notes should be numbered using the same numbering system as the bibliographic references.

Journals The style of journal abbreviations to be used in RSC publications is that defined in Chemical Abstracts Service Source Index (CASSI) (http://www.cas.org/expertise/cascontent/caplus/corejournals.html).

Bibliographic details should be cited in the order: year, volume , page. Where page numbers are not yet known, articles should be cited by DOI (Digital Object Identifier) - for example, T. J. Hebden, R. R. Schrock, M. K. Takase and P. Müller, Chem. Commun ., 2012, DOI: 10.1039/C2CC17634C.

Books J. Barker, in Catalyst Deactivation , ed. B. Delmon and C. Froment, Elsevier, Amsterdam, 2nd edn., 1987, vol. 1, ch. 4, pp. 253-255.

Patents Br. Pat ., 357 450, 1986. US Pat ., 1 171 230, 1990.

Reports and bulletins, etc R. A. Allen, D. B. Smith and J. E. Hiscott, Radioisotope Data , UKAEA Research Group Report AERE-R 2938, H.M.S.O., London, 1961.

Material presented at meetings H. C. Freeman, Proceedings of the 21st International Conference on Coordination Chemistry, Toulouse, 1980.

Theses A. D. Mount, Ph.D. Thesis, University of London, 1977.

Reference to unpublished material For material presented at a meeting, congress or before a Society, etc., but not published, the following form is used:  A. R. Jones, presented in part at the 28th Congress of the International Union of Pure and Applied Chemistry, Vancouver, August, 1981.

For material accepted for publication, but not yet published, the following forms are used.

• A. R. Jones, Dalton Trans. , 2003, DOI: 10.1039/manuscript number, for RSC journals 
• A. R. Jones, Angew. Chem ., in press, for non-RSC journals

If DOI numbers are known these should be cited in the form recommended by the publisher.

For material submitted for publication but not yet accepted the following form is used.

• A. R. Jones, Angew. Chem ., submitted.

For personal communications the following is used.

• G. B. Ball, personal communication.

If material is to be published but has yet to be submitted the following form is used.

• G. B. Ball, unpublished work.

Reference to unpublished work should not be made without the permission of those by whom the work was performed.

Software F James,  AIM2000, version 1.0, University of Applied Sciences, Bielefeld,  Germany, 2000. T Bellander, M Lewne and B Brunekreef, GAUSSIAN 3 (Revision B.05), Gaussian Inc., Pittsburgh, PA, 2003.

Online resources (including databases) Please note the most important information to include is the URL and the data accessed.

• The Merck Index Online, http://www.rsc.org/Merck-lndex/monograph/mono1500000841, (accessed October 2013).
• ChemSpider, http://www.chemspider.com/Chemicai-Structure.1906.html, (accessed June 2011).

arXiv references V. Krstic and M. Glerup, 2006, arXiv:cond-mat/0601513.

Figures & schemes

Preparation of graphics.

Artwork should be submitted at its final size so that reduction is not required. The appearance of graphics is the responsibility of the author.

• Graphics should fit within either single column (8.3 cm) or double column (17.1 cm) width, and must be no longer than 23.3 cm.
• Graphical abstracts should be no larger than 8 x 4 cm.
• Schemes and structures should be drawn to make best use of single and double column widths.

Colour figures

Colour figure reproduction is provided free of charge both online and in print.

Journal covers

Authors who wish to have their artwork featured on a journal cover should contact the editorial office of the journal to which the article is being submitted. A contribution to the additional production costs will be requested.

Use of such artwork is at the editor's discretion; the editor's decision is final. Examples of previous journal covers can be viewed via the journal homepage.

Electronic supplementary information

The journal's electronic supplementary information (ESI) service is a free facility that enables authors to enhance and increase the impact of their articles. Authors are encouraged to make the most of the benefits of publishing supplementary information in electronic form. Such data can take full advantage of the electronic medium, allowing use of 3D molecular models and movies. Authors can also improve the readability of their articles by placing appropriate material, such as repetitive experimental details and bulky data, as ESI. All information published as ESI is also fully archived. When preparing their ESI data files, authors should keep in mind the following points.

• Supplementary data is peer-reviewed, and should therefore be included with the original submission.
• ESI files are published 'as is'; editorial staff will not usually edit the data for style or content.
• Data is useful only if readers can access it; use common file formats.
• Large files may prove difficult for users to download and access.

Text and graphics

The preferred format for ESI comprising text and graphics is Microsoft Word. Publishing staff will convert Word files to PDF before publication, as this format can be accessed easily and reliably on most computing platforms using the freely available Adobe Acrobat Reader. If other formats are submitted they will also usually be converted to PDF files prior to publication.

Multimedia files

We welcome submission of multimedia files (including videos and animations) alongside articles for publication. Videos are an excellent medium to present elements of your work that can be difficult to communicate only in words. Please note that any videos of general interest are shared with the wider community via the RSC Journals YouTube channel. Please notify the editorial team if you prefer for your video(s) not to be uploaded to YouTube. If you submit a multimedia file alongside your paper, please refer to it within your paper to draw it to the reader’s attention. Also please see the section on submitting multimedia files

Format Acceptable formats for video or animation clips are listed below.

Please minimise file sizes where you can, by considering the following points.

• The recommended maximum frame size is 640 x 480 pixels.
• Our recommended maximum file size is 5 Mb.
• Many packages output 30 frames per second (fps) as standard, but it's possible to specify a lower frame rate; this may not noticeably affect the quality of your video but will reduce the file size.
• Use a 256 colour palette, if that is suitable for the presentation of the material.

Please consider the use of lower specifications for all these points if the material can still be represented clearly.

If your video is very short (that is, several seconds long) then it is recommended that you loop it and repeat a few times to provide a more detailed view.

Submitting multimedia files Upload your video online, together with your manuscript under the category 'electronic supplementary material' and please supply the following.

• A clear file name for your video.
• A short descriptive title for the video, which can be used when uploading the video onto a streaming channel.
• A video legend of approximately 30 words long; this caption must be provided to aid discoverability.
• Five to 10 keywords that can be used to tag the video; the more accurate the tags are the better discoverability videos will have.

Copies of any relevant 'in press' references

Manuscripts should be submitted with copies of any ‘in press’ articles referenced.

Open access publishing options

Environmental Science: Water Research & Technology  is a hybrid (transformative) journal and gives authors the choice of publishing their research either via the traditional subscription-based model or instead by choosing our gold open access option.  Find out more about our Transformative Journals. which are Plan S compliant .

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Wastewater Treatment and Reuse: a Review of its Applications and Health Implications

• Open access
• Published: 10 May 2021
• Volume 232 , article number  208 , ( 2021 )

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• Kavindra Kumar Kesari   ORCID: orcid.org/0000-0003-3622-9555 1   na1 ,
• Ramendra Soni 2   na1 ,
• Qazi Mohammad Sajid Jamal 3 ,
• Pooja Tripathi 4 ,
• Jonathan A. Lal 2 ,
• Niraj Kumar Jha 5 ,
• Mohammed Haris Siddiqui 6 ,
• Pradeep Kumar 7 ,
• Vijay Tripathi 2 &
• Janne Ruokolainen 1  

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Water scarcity is one of the major problems in the world and millions of people have no access to freshwater. Untreated wastewater is widely used for agriculture in many countries. This is one of the world-leading serious environmental and public health concerns. Instead of using untreated wastewater, treated wastewater has been found more applicable and ecofriendly option. Moreover, environmental toxicity due to solid waste exposures is also one of the leading health concerns. Therefore, intending to combat the problems associated with the use of untreated wastewater, we propose in this review a multidisciplinary approach to handle wastewater as a potential resource for use in agriculture. We propose a model showing the efficient methods for wastewater treatment and the utilization of solid wastes in fertilizers. The study also points out the associated health concern for farmers, who are working in wastewater-irrigated fields along with the harmful effects of untreated wastewater. The consumption of crop irrigated by wastewater has leading health implications also discussed in this review paper. This review further reveals that our current understanding of the wastewater treatment and use in agriculture with addressing advancements in treatment methods has great future possibilities.

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1 Introduction

Rapidly depleting and elevating the level of freshwater demand, though wastewater reclamation or reuse is one of the most important necessities of the current scenario. Total water consumption worldwide for agriculture accounts 92% (Clemmens et al., 2008 ; Hoekstra & Mekonnen, 2012 ; Tanji & Kielen, 2002 ). Out of which about 70% of freshwater is used for irrigation (WRI, 2020 ), which comes from the rivers and underground water sources (Pedrero et al., 2010 ). The statistics shows serious concern for the countries facing water crisis. Shen et al. ( 2014 ) reported that 40% of the global population is situated in heavy water–stressed basins, which represents the water crisis for irrigation. Therefore, wastewater reuse in agriculture is an ideal resource to replace freshwater use in agriculture (Contreras et al., 2017 ). Treated wastewater is generally applied for non-potable purposes, like agriculture, land, irrigation, groundwater recharge, golf course irrigation, vehicle washing, toilet flushes, firefighting, and building construction activities. It can also be used for cooling purposes in thermal power plants (Katsoyiannis et al., 2017 ; Mohsen, 2004 ; Smith, 1995 ; Yang et al., 2017 ). At global level, treated wastewater irrigation supports agricultural yield and the livelihoods of millions of smallholder farmers (Sato et al., 2013 ). Global reuse of treated wastewater for agricultural purposes shows wide variability ranging from 1.5 to 6.6% (Sato et al., 2013 ; Ungureanu et al., 2018 ). More than 10% of the global population consumes agriculture-based products, which are cultivated by wastewater irrigation (WHO, 2006 ). Treated wastewater reuse has experienced very rapid growth and the volumes have been increased ~10 to 29% per year in Europe, the USA, China, and up to 41% in Australia (Aziz & Farissi, 2014 ). China stands out as the leading country in Asia for the reuse of wastewater with an estimated 1.3 M ha area including Vietnam, India, and Pakistan (Zhang & Shen, 2017 ). Presently, it has been estimated that, only 37.6% of the urban wastewater in India is getting treated (Singh et al., 2019 ). By utilizing 90% of reclaimed water, Israel is the largest user of treated wastewater for agriculture land irrigation (Angelakis & Snyder, 2015 ). The detail information related to the utilization of freshwater and treated wastewater is compiled in Table 1 .

Many low-income countries in Africa, Asia, and Latin America use untreated wastewater as a source of irrigation (Jiménez & Asano, 2008 ). On the other hand, middle-income countries, such as Tunisia, Jordan, and Saudi Arabia, use treated wastewater for irrigation (Al-Nakshabandi et al., 1997 ; Balkhair, 2016a ; Balkhair, 2016b ; Qadir et al., 2010 ; Sato et al., 2013 ).

Domestic water and treated wastewater contains various type of nutrients such as phosphorus, nitrogen, potassium, and sulfur, but the major amount of nitrogen and phosphorous available in wastewater can be easily accumulated by the plants, that’s why it is widely used for the irrigation (Drechsel et al., 2010 ; Duncan, 2009 ; Poustie et al., 2020 ; Sengupta et al., 2015 ). The rich availability of nutrients in reclaimed wastewater reduces the use of fertilizers, increases crop productivity, improves soil fertility, and at the same time, it may also decrease the cost of crop production (Chen et al., 2013 a; Jeong et al., 2016 ). The data of high nutritional values in treated wastewater is shown in Fig. 1 .

Nutrient concentrations (mg/L) of freshwater/wastewater (Yadav et al., 2002 )

Wastewater reuse for crop irrigation showed several health concerns (Ungureanu et al., 2020 ). Irrigation with the industrial wastewater either directly or mixing with domestic water showed higher risk (Chen et al., 2013). Risk factors are higher due to heavy metal and pathogens contamination because heavy metals are non-biodegradable and have a long biological half-life (Chaoua et al., 2019 ; WHO, 2006 ). It contains several toxic elements, i.e., Cu, Cr, Mn, Fe, Pb, Zn, and Ni (Mahfooz et al., 2020 ). These heavy metals accumulate in topsoil (at a depth of 20 cm) and sourcing through plant roots; they enter the human and animal body through leafy vegetables consumption and inhalation of contaminated soils (Mahmood et al., 2014 ). Therefore, health risk assessment of such wastewater irrigation is important especially in adults (Mehmood et al., 2019 ; Njuguna et al., 2019 ; Xiao et al., 2017 ). For this, an advanced wastewater treatment method should be applied before release of wastewater in the river, agriculture land, and soils. Therefore, this review also proposed an advance wastewater treatment model, which has been tasted partially at laboratory scale by Kesari and Behari ( 2008 ), Kesari et al. ( 2011a , b ), and Kumar et al. ( 2010 ).

For a decade, reuse of wastewater has also become one of the global health concerns linking to public health and the environment (Dang et al., 2019 ; Narain et al., 2020 ). The World Health Organization (WHO) drafted guidelines in 1973 to protect the public health by facilitating the conditions for the use of wastewater and excreta in agriculture and aquaculture (WHO, 1973 ). Later in 2005, the initial guidelines were drafted in the absence of epidemiological studies with minimal risk approach (Carr, 2005 ). Although, Adegoke et al. ( 2018 ) reviewed the epidemiological shreds of evidence and health risks associated with reuse of wastewater for irrigation. Wastewater or graywater reuse has adverse health risks associated with microbial hazards (i.e., infectious pathogens) and chemicals or pharmaceuticals exposures (Adegoke et al., 2016 ; Adegoke et al., 2017 ; Busgang et al., 2018 ; Marcussen et al., 2007 ; Panthi et al., 2019 ). Researchers have reported that the exposure to wastewater may cause infectious (helminth infection) diseases, which are linked to anemia and impaired physical and cognitive development (Amoah et al., 2018 ; Bos et al., 2010 ; Pham-Duc et al., 2014 ; WHO, 2006 ).

Owing to an increasing population and a growing imbalance in the demand and supply of water, the use of wastewater has been expected to increase in the coming years (World Bank, 2010 ). The use of treated wastewater in developed nations follows strict rules and regulations. However, the direct use of untreated wastewater without any sound regulatory policies is evident in developing nations, which leads to serious environmental and public health concerns (Dickin et al., 2016 ). Because of these issues, we present in this review, a brief discussion on the risk associated with the untreated wastewater exposures and advanced methods for its treatment, reuse possibilities of the treated wastewater in agriculture.

2 Environmental Toxicity of Untreated Wastewater

Treated wastewater carries larger applicability such as irrigation, groundwater recharge, toilet flushing, and firefighting. Municipal wastewater treatment plants (WWTPs) are the major collection point for the different toxic elements, pathogenic microorganisms, and heavy metals. It collects wastewater from divergent sources like household sewage, industrial, clinical or hospital wastewater, and urban runoff (Soni et al., 2020 ). Alghobar et al. ( 2014 ) reported that grass and crops irrigated with sewage and treated wastewater are rich in heavy metals in comparison with groundwater (GW) irrigation. Although, heavy metals classified as toxic elements and listed as cadmium, lead, mercury, copper, and iron. An exceeding dose or exposures of these heavy metals could be hazardous for health (Duan et al., 2017 ) and ecological risks (Tytła, 2019 ). The major sources of these heavy metals come from drinking water. This might be due to the release of wastewater into river or through soil contamination reaches to ground water. Table 2 presenting the permissible limits of heavy metals presented in drinking water and its impact on human health after an exceeding the amount in drinking water, along with the route of exposure of heavy metals to human body.

Direct release in river or reuse of wastewater for irrigation purposes may create short-term implications like heavy metal and microbial contamination and pathogenic interaction in soil and crops. It has also long-term influence like soil salinity, which grows with regular use of untreated wastewater (Smith, 1995 ). Improper use of wastewater for irrigation makes it unsafe and environment threatening. Irrigation with several different types of wastewater, i.e., industrial effluents, municipal and agricultural wastewaters, and sewage liquid sludge transfers the heavy metals to the soil, which leads to accumulation in crops due to improper practices. This has been identified as a significant route of heavy metals into aquatic resources (Agoro et al., 2020 ). Hussain et al. ( 2019 ) investigated the concentration of heavy metals (except for Cd) was higher in the soil irrigated with treated wastewater (large-scale sewage treatment plant) than the normal ground water, also reported by Khaskhoussy et al. ( 2015 ).

In other words, irrigation with wastewater mitigates the quality of crops and enhances health risks. Excess amount of copper causes anemia, liver and kidney damage, vomiting, headache, and nausea in children (Bent & Bohm, 1995 ; Madsen et al., 1990 ; Salem et al., 2000 ). A higher concentration of arsenic may lead to bone and kidney cancer (Jarup, 2003 ) and results in osteopenia or osteoporosis (Puzas et al., 2004 ). Cadmium gives rise to musculoskeletal diseases (Fukushima et al., 1970 ), whereas mercury directly affects the nervous system (Azevedo et al., 2014 ).

3 Spread of Antibiotic Resistance

Currently, antibiotics are highly used for human disease treatment; however, uses in poultries, animal husbandries, biochemical industries, and agriculture are common practices these days. Extensive use and/or misuse of antibiotics have given rise to multi-resistant bacteria, which carry multiple resistance genes (Icgen & Yilmaz, 2014 ; Lv et al., 2015 ; Tripathi & Tripathi, 2017 ; Xu et al., 2017 ). These multidrug-resistant bacteria discharged through the sewage network and get collected into the wastewater treatment plants. Therefore, it can be inferred that the WWTPs serve as the hotspot of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs). Though, these antibiotic-resistant bacteria can be disseminated to the different bacterial species through the mobile genetic elements and horizontal gene transfer (Gupta et al., 2018 ). Previous studies indicated that certain pathogens might survive in wastewater, even during and after the treatment processes, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) (Börjesson et al., 2009 ; Caplin et al., 2008 ). The use of treated wastewater in irrigation provides favorable conditions for the growth and persistence of total coliforms and fecal coliforms (Akponikpe et al., 2011 ; Sacks & Bernstein, 2011 ). Furthermore, few studies have also reported the presence of various bacterial pathogens, such as Clostridium , Salmonella , Streptococci , Viruses, Protozoa, and Helminths in crops irrigated with treated wastewater (Carey et al., 2004 ; Mañas et al., 2009 ; Samie et al., 2009 ). Goldstein ( 2013 ) investigated the survival of ARB in secondary treated wastewater and proved that it causes serious health risks to the individuals, who are exposed to reclaimed water. The U.S. Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) have already declared the ARBs as the imminent hazard to human health. According to the list published by WHO, regarding the development of new antimicrobial agents, the ESKAPE ( Enterococcus faecium , S. aureus , Klebsiella pneumoniae , Acinetobacter baumannii , Pseudomonas aeruginosa , and Enterobacter species) pathogens were designated to be “priority status” as their occurrence in the food chain is considered as the potential and major threat for the human health (Tacconelli et al., 2018 ).

These ESKAPE pathogens have acquired the multi drug resistance mechanisms against oxazolidinones, lipopeptides, macrolides, fluoroquinolones, tetracyclines, β-lactams, β-lactam–β-lactamase inhibitor combinations, and even those antibiotics that are considered as the last line of defense, including carbapenems and glycopeptides (Giddins et al., 2017 ; Herc et al., 2017 ; Iguchi et al., 2016 ; Naylor et al., 2018 ; Zaman et al., 2017 ), by the means of genetic mutation and mobile genetic elements. These cluster of ESKAPE pathogens are mainly responsible for lethal nosocomial infections (Founou et al., 2017 ; Santajit & Indrawattana, 2016 ).

Due to the wide application of antibiotics in animal husbandry and inefficient capability of wastewater treatment plants, the multidrug-resistant bacteria such as tetracyclines, sulfonamides, β-lactam, aminoglycoside, colistin, and vancomycin in major are disseminated in the receiving water bodies, which ultimately results in the accumulation of ARGs in the irrigated crops (He et al., 2020 ).

4 Toxic Contaminations in Wastewater Impacting Human Health

The release of untreated wastewater into the river may pose serious health implications (König et al., 2017 ; Odigie, 2014 ; Westcot, 1997 ). It has been already discussed about the household and municipal sewage which contains a major amount of organic materials and pathogenic microorganisms and these infectious microorganisms are capable of spreading various diseases like typhoid, dysentery, diarrhea, vomiting, and malabsorption (Jia & Zhang, 2020 ; Numberger et al., 2019 ; Soni et al., 2020 ). Additionally, pharmaceutical industries also play a key role in the regulation and discharge of biologically toxic agents. The untreated wastewater also contains a group of contaminants, which are toxic to humans. These toxic contaminations have been classified into two major groups: (i) chemical contamination and (ii) microbial contamination.

4.1 Chemical Contamination

Mostly, various types of chemical compounds released from industries, tanneries, workshops, irrigated lands, and household wastewaters are responsible for several diseases. These contaminants can be organic materials, hydrocarbons, volatile compounds, pesticides, and heavy metals. Exposure to such contaminants may cause infectious diseases like chronic dermatoses and skin cancer, lung infection, and eye irritation. Most of them are non-biodegradable and intractable. Therefore, they can persist in the water bodies for a very long period and could be easily accumulated in our food chain system. Several pharmaceutical personal care products (PPCPs) and surfactants are available that may contain toxic compounds like nonylphenol, estrone, estradiol, and ethinylestradiol. These compounds are endocrine-disrupting chemicals (Bolong et al., 2009 ), and the existence of these compounds in the human body even in the trace amounts can be highly hazardous. Also, the occurrence of perfluorinated compounds (PFCs) in wastewater, which is toxic in nature, has been significantly reported worldwide (Templeton et al., 2009 ). Furthermore, PFCs cause severe health menaces like pre-eclampsia, birth defects, reduced human fertility (Webster, 2010 ), immunotoxicity (Dewitt et al., 2012 ), neurotoxicity (Lee & Viberg, 2013 ), and carcinogenesis (Bonefeld-Jorgensen et al., 2011 ).

4.2 Microbial Contamination

Researchers have reported serious health risks associated with the microbial contaminants in untreated wastewater. The diverse group of microorganisms causes severe health implications like campylobacteriosis, diarrhea, encephalitis, typhoid, giardiasis, hepatitis A, poliomyelitis, salmonellosis, and gastroenteritis (ISDH, 2009 ; Okoh et al., 2010 ). Few bacterial species like P. aeruginosa , Salmonella typhimurium , Vibrio cholerae , G. intestinales , Legionella spp., E. coli , Shigella sonnei have been reported for the spreading of waterborne diseases, and acute illness in human being (Craun et al., 2006 ; Craun et al., 2010 ). These aforementioned microorganisms may release in the environment from municipal sewage water network, animal husbandries, or hospitals and enter the food chain via public water supply systems.

5 Wastewater Impact on Agriculture

The agriculture sector is well known for the largest user of water, accounting for nearly 70% of global water usage (Winpenny et al., 2010 ). The fact that an estimated 20 million hectares worldwide are irrigated with wastewater suggests a major source for irrigation (Ecosse, 2001 ). However, maximum wastewater that is used for irrigation is untreated (Jiménez & Asano, 2008 ; Scott et al., 2004 ). Mostly in developing countries, partially treated or untreated wastewater is used for irrigation purpose (Scott et al., 2009 ). Untreated wastewater often contains a large range of chemical contaminants from waste sites, chemical wastes from industrial discharges, heavy metals, fertilizers, textile, leather, paper, sewage waste, food processing waste, and pesticides. World Health Organization (WHO) has warned significant health implications due to the direct use of wastewater for irrigation purposes (WHO, 2006 ). These contaminants pose health risks to communities (farmers, agricultural workers, their families, and the consumers of wastewater-irrigated crops) living in the proximity of wastewater sources and areas irrigated with untreated wastewater (Qadir et al., 2010 ). Wastewater also contains a wide variety of organic compounds. Some of them are toxic or cancer-causing and have harmful effects on an embryo (Jarup, 2003 ; Shakir et al., 2016 ). The pathway of untreated wastewater used in irrigation and associated health effects are shown in Fig. 2 .

Exposure pathway representing serious health concerns from wastewater-irrigated crops

Alternatively, in developing countries, due to the limited availability of treatment facilities, untreated wastewater is discharged into the existing waterbodies (Qadir et al., 2010 ). The direct use of wastewater in agriculture or irrigation obstructs the growth of natural plants and grasses, which in turn causes the loss of biodiversity. Shuval et al. ( 1985 ) reported one of the earliest evidences connecting to agricultural wastewater reuse with the occurrence of diseases. Application of untreated wastewater in irrigation increases soil salinity, land sealing followed by sodium accumulation, which results in soil erosion. Increased soil salinity and sodium accumulation deteriorates the soil and decreases the soil permeability, which inhibits the nutrients intake of crops from the soil. These causes have been considered the long-term impact of wastewater reuse in agriculture (Halliwell et al., 2001 ). Moreover, wastewater contaminated soils are a major source of intestinal parasites (helminths—nematodes and tapeworms) that are transmitted through the fecal–oral route (Toze, 1997 ). Already known, the helminth infections are linked to blood deficiency and behavioral or cognitive development (Bos et al., 2010 ). One of the major sources of helminth infections around the world is the use of raw or partially treated sewage effluent and sludge for the irrigation of food crops (WHO, 1989 ). Wastewater-irrigated crops contain heavy metal contamination, which originates from mining, foundries, and metal-based industries (Fazeli et al., 1998 ). Exposure to heavy metals including arsenic, cadmium, lead, and mercury in wastewater-irrigated crops is a cause for various health problems. For example, the consumption of high amounts of cadmium causes osteoporosis in humans (Dickin et al., 2016 ). The uptake of heavy metals by the rice crop irrigated with untreated effluent from a paper mill has been reported to cause serious health concerns (Fazeli et al., 1998 ). Irrigating rice paddies with highly contaminated water containing heavy metals leads to the outbreak of Itai-itai disease in Japan (Jarup, 2003 ).

Owing to these widespread health risks, the WHO published the third edition of its guidelines for the safe use of wastewater in irrigating crops (WHO, 2006 ) and made recommendations for threshold contaminant levels in wastewater. The quality of wastewater for agricultural reuse have been classified based on the availability of nutrients, trace elements, microorganisms, and chemicals contamination levels. The level of contamination differs widely depending on the type of source, household sewage, pharmaceutical, chemical, paper, or textile industries effluents. The standard measures of water quality for irrigation are internationally reported (CCREM, 1987 ; FAO, 1985 ; FEPA, 1991 ; US EPA, 2004 , 2012 ; WHO, 2006 ), where the recommended levels of trace elements, metals, COD, BOD, nitrogen, and phosphorus are set at certain limits. Researchers reviewed the status of wastewater reuse for agriculture, based on its standards and guidelines for water quality (Angelakis et al., 1999 ; Brissaud, 2008 ; Kalavrouziotis et al., 2015 ). Based on these recommendations and guidelines, it is evident that greater awareness is required for the treatment of wastewater safely.

6 Wastewater Treatment Techniques

6.1 primary treatment.

This initial step is designed to remove gross, suspended and floating solids from raw wastewater. It includes screening to trap solid objects and sedimentation by gravity to remove suspended solids. This physical solid/liquid separation is a mechanical process, although chemicals can be used sometimes to accelerate the sedimentation process. This phase of the treatment reduces the BOD of the incoming wastewater by 20–30% and the total suspended solids by nearly 50–60%.

6.2 Secondary (Biological) Treatment

This stage helps eliminate the dissolved organic matter that escapes primary treatment. Microbes consume the organic matter as food, and converting it to carbondioxide, water, and energy for their own growth. Additional settling to remove more of the suspended solids then follows the biological process. Nearly 85% of the suspended solids and biological oxygen demand (BOD) can be removed with secondary treatment. This process also removes carbonaceous pollutants that settle down in the secondary settling tank, thus separating the biological sludge from the clear water. This sludge can be fed as a co-substrate with other wastes in a biogas plant to obtain biogas, a mixture of CH 4 and CO 2 . It generates heat and electricity for further energy distribution. The leftover, clear water is then processed for nitrification or denitrification for the removal of carbon and nitrogen. Furthermore, the water is passed through a sedimentation basin for treatment with chlorine. At this stage, the water may still contain several types of microbial, chemical, and metal contaminations. Therefore, to make the water reusable, e.g., for irrigation, it further needs to pass through filtration and then into a disinfection tank. Here, sodium hypochlorite is used to disinfect the wastewater. After this process, the treated water is considered safe to use for irrigation purposes. Solid wastes generated during primary and secondary treatment processes are processed further in the gravity-thickening tank under a continuous supply of air. The solid waste is then passed into a centrifuge dewatering tank and finally to a lime stabilization tank. Treated solid waste is obtained at this stage and it can be processed further for several uses such as landfilling, fertilizers and as a building.

Other than the activated sludge process of wastewater treatment, there are several other methods developed and being used in full-scale reactors such as ponds (aerobic, anaerobic, facultative, and maturation), trickling filters, anaerobic treatments like up-flow anaerobic sludge blanket (UASB) reactors, artificial wetlands, microbial fuel cells, and methanogenic reactors.

UASB reactors are being applied for wastewater treatment from a very long period. Behling et al. ( 1996 ) examined the performance of the UASB reactor without any external heat supply. In their study, the COD loading rate was maintained at 1.21 kg COD/m 3 /day, after 200 days of trial. They achieved an average of 85% of COD removal. Von-Sperling and Chernicharo ( 2005 ) presented a combined model consisted of an Up-flow Anaerobic Sludge Blanket-Activated Sludge reactor (UASB–AS system), using the low strength domestic wastewater with a BOD 5 amounting to 340 mg/l. Outcomes of their experiment have shown a 60% reduction in sludge construction and a 40% reduction in aeration energy consumption. In another experiment, Rizvi et al. ( 2015 ) seeded UASB reactor with cow manure dung to treat domestic wastewater; they observed 81%, 75%, and 76% reduction in COD, TSS, and total sulfate removal, respectively, in their results.

6.3 Tertiary or Advanced Treatment Processes

The tertiary treatment process is employed when specific constituents, substances, or contaminants cannot be completely removed after the secondary treatment process. The tertiary treatment processes, therefore, ensure that nearly 99% of all impurities are removed from wastewater. To make the treated water safe for drinking purposes, water is treated individually or in combination with advanced methods like the US (ultrasonication), UV (ultraviolet light treatment), and O 3 (exposure to ozone). This process helps to remove bacteria and heavy metal contaminations remaining in the treated water. For the purpose, the secondarily treated water is first made to undergo ultrasonication and it is subsequently exposed to UV light and passed through an ozone chamber for the complete removal of contaminations. The possible mechanisms by which cells are rendered inviable during the US include free-radical attack and physical disruption of cell membranes (Phull et al., 1997 ; Scherba et al., 1991 ). The combined treatment of US + UV + O 3 produces free radicals, which are attached to cell membranes of the biological contaminants. Once the cell membrane is sheared, chemical oxidants can enter the cell and attack internal structures. Thus, the US alone or in combination facilitates the deagglomeration of microorganisms and increases the efficiency of other chemical disinfectants (Hua & Thompson, 2000 ; Kesari et al., 2011a , b ; Petrier et al., 1992 ; Phull et al., 1997 ; Scherba et al., 1991 ). A combined treatment method was also considered by Pesoutova et al. ( 2011 ) and reported a very effective method for textile wastewater treatment. The effectiveness of ultrasound application as a pre-treatment step in combination with ultraviolet rays (Blume & Neis, 2004 ; Naddeo et al., 2009 ), or also compared it with various other combinations of both ultrasound and UV radiation with TiO 2 photocatalysis (Paleologou et al., 2007 ), and ozone (Jyoti & Pandit, 2004 ) to optimize wastewater disinfection process.

An important aspect of our wastewater treatment model (Fig. 3 ) is that at each step of the treatment process, we recommend the measurement of the quality of treated water. After ensuring that the proper purification standards are met, the treated water can be made available for irrigation, drinking or other domestic uses.

A wastewater treatment schematic highlighting the various methods that result in a progressively improved quality of the wastewater from the source to the intended use of the treated wastewater for irrigation purposes

6.4 Nanotechnology as Tertiary Treatment of Wastewater Converting Drinking Water Alike

Considering the emerging trends of nanotechnology, nanofillers can be used as a viable method for the tertiary treatment of wastewater. Due to the very small pore size, 1–5-nm nanofillers may eliminate the organic–inorganic pollutants, heavy metals, as well as pathogenic microorganisms and pharmaceutically active compounds (PhACs) (Mohammad et al., 2015 ; Vergili, 2013 ). Over the recent years, nanofillers have been largely accepted in the textile industry for the treatment of pulp bleaching pharmaceutical industry, dairy industry, microbial elimination, and removal of heavy metals from wastewater (Abdel-Fatah, 2018 ). Srivastava et al. ( 2004 ) synthesized very efficient and reusable water filters from carbon nanotubes, which exhibited effective elimination of bacterial pathogens ( E. coli and S. aureus ), and Poliovirus sabin-1 from wastewater.

Nanofiltration requires lower operating pressure and lesser energy consumption in comparison of RO and higher rejection of organic compounds compared to UF. Therefore, it can be applied as the tertiary treatment of wastewater (Abdel-Fatah, 2018 ). Apart from nanofilters, there are various kinds of nanoparticles like metal nanoparticles, metal oxide nanoparticles, carbon nanotubes, graphene nanosheets, and polymer-based nanosorbents, which may play a different role in wastewater treatment based on their properties. Kocabas et al. ( 2012 ) analyzed the potential of different metal oxide nanoparticles and observed that nanopowders of TiO 2 , FeO 3 , ZnO 2 , and NiO can exhibit the exceeding amount of removal of arsenate from wastewater. Cadmium contamination in wastewater, which poses a serious health risk, can be overcome by using ZnO nanoparticles (Kumar & Chawla, 2014 ). Latterly, Vélez et al. ( 2016 ) investigated that the 70% removal of mercury from wastewater through iron oxide nanoparticles successfully performed. Sheet et al. ( 2014 ) used graphite oxide nanoparticles for the removal of nickel from wastewater. An exceeding amount of copper causes liver cirrhosis, anemia, liver, and kidney damage, which can be removed by carbon nanotubes, pyromellitic acid dianhydride (PMDA) and phenyl aminomethyl trimethoxysilane (PAMTMS) (Liu et al., 2010 ).

Nanomaterials are efficiently being used for microbial purification from wastewater. Carbon nanotubes (CNTs) are broadly applied for the treatment of wastewater contaminated with E. coli , Salmonella , and a wide range of microorganisms (Akasaka & Watari, 2009 ). In addition, silver nanoparticles reveal very effective results against the microorganisms present in wastewater. Hence, it is extensively being used for microbial elimination from wastewater (Inoue et al., 2002 ). Moreover, CNTs exhibit high binding affinity to bacterial cells and possess magnetic properties (Pan & Xing, 2008 ). Melanta ( 2008 ) confirmed and recommended the applicability of CNTs for the removal of E. coli contamination from wastewater. Mostafaii et al. ( 2017 ) suggested that the ZnO nanoparticles could be the potential antibacterial agent for the removal of total coliform bacteria from municipal wastewater. Apart from the previously mentioned, applicability of the nanotechnology, the related drawbacks and challenges cannot be neglected. Most of the nanoengineered techniques are currently either in research scale or pilot scale performing well (Gehrke et al., 2015 ). Nevertheless, as discussed above, nanotechnology and nanomaterials exhibit exceptional properties for the removal of contaminants and purification of water. Therefore, it can be adapted as the prominent solution for the wastewater treatment (Zekić et al., 2018 ) and further use for drinking purposes.

6.5 Wastewater Treatment by Using Plant Species

Some of the naturally growing plants can be a potential source for wastewater treatment as they remove pollutants and contaminants by utilizing them as a nutrient source (Zimmels et al., 2004 ). Application of plant species in wastewater treatment may be cost-effective, energy-saving, and provides ease of operation. At the same time, it can be used as in situ, where the wastewater is being produced (Vogelmann et al., 2016 ). Nizam et al. ( 2020 ) analyzed the phytoremediation efficiency of five plant species ( Centella asiatica , Ipomoea aquatica , Salvinia molesta , Eichhornia crassipes , and Pistia stratiotes ) and achieved the drastic decrease in the amount of three pollutants viz. total suspended solids (TSS), ammoniacal nitrogen (NH 3 -N), and phosphate levels . All the five species found to be efficient removal of the level of 63.9-98% of NH 3 -N, TSS, and phosphate. Coleman et al. ( 2001 ) examined the physiological effects of domestic wastewater treatment by three common Appalachian plant species: common rush or soft rush ( Juncus effuses L.), gray club-rush ( Scirpus Validus L.), and broadleaf cattail or bulrush ( Typha latifolia L.). They observed in their experiments about 70% of reduction in total suspended solids (TSS) and biochemical oxygen demand (BOD), 50% to 60% of reduction in nitrogen, ammonia, and phosphate levels, and a significant reduction in feacal coliform populations. Whereas, Zamora et al. ( 2019 ) found the removal efficiency of chemical oxygen demand (COD), total solids suspended (TSS), nitrogen as ammonium (N-NH 4 ) and nitrate (N-NO 3 ), and phosphate (P-PO 4 ) up to 20–60% higher using the three ornamental species of plants viz. Canna indica , Cyperus papyrus , and Hedychium coronarium . The list of various plant species applied for the wastewater treatment is shown in Table 3 .

6.6 Wastewater Treatment by Using Microorganisms

There is a diverse group of bacteria like Pseudomonas fluorescens , Pseudomonas putida , and different Bacillus strains, which are capable to use in biological wastewater systems. These bacteria work in the cluster forms as a floc, biofilm, or granule during the wastewater treatment. Furthermore, after the recognition of bacterial exopolysaccharides (EPS) as an efficient adsorption material, it may be applied in a revolutionary manner for the heavy metal elimination (Gupta & Diwan, 2017 ). There are few examples of EPS, which are commercially available, i.e., alginate ( P. aeruginosa , Azotobacter vinelandii ), gellan (Sphingomonas paucimobilis ), hyaluronan ( . aeruginosa , Pasteurella multocida , Streptococci attenuated strains ), xanthan (Xanthomonas campestris ), and galactopol ( Pseudomonas oleovorans ) (Freitas et al., 2009 ; Freitas, Alves, & Reis, 2011a ; Freitas, Alves, Torres, et al., 2011b ). Similarly, Hesnawi et al. ( 2014 ) experimented biodegradation of municipal wastewater using local and commercial bacteria (Sludge Hammer), where they achieved a significant decrease in synthetic wastewater, i.e., 70%, 54%, 52%, 42% for the Sludge Hammer, B. subtilis , B. laterosponus , and P. aeruginosa , respectively. Therefore, based on the above studies, it can be concluded that bioaugmentation of wastewater treatment reactor with selective and mixed strains can ameliorate the treatment. During recent years, microalgae have attracted the attention of researchers as an alternative system, due to their applicability in wastewater treatment. Algae are the unicellular or multicellular photosynthetic microorganism that grows on water surfaces, salt water, or moist soil. They utilize the exceeding amount of nutrients like nitrogen, phosphorus, and carbon for their growth and metabolism process through their anaerobic system. This property of algae also inhibits eutrophication; that is to avoid over-deposit of nutrients in water bodies. During the nutrient digestion process, algae produce oxygen that is constructive for the heterotrophic aerobic bacteria, which may further be utilized to degrade the organic and inorganic pollutants. Kim et al. ( 2014 ) observed a total decrease in the levels of COD (86%), total nitrogen (93%), and total phosphorus (83%) after using algae in the municipal wastewater consortium. Nmaya et al. ( 2017 ) reported the heavy metal removal efficiency of microalga Scenedesmus sp. from contaminated river water in the Melaka River, Malaysia. They observed the effective removal of Zn (97-99%) on the 3 rd and 7 th day of the experiment. The categorized list of microorganisms used for wastewater treatment is presented in Table 4 .

7 The Computational Approach in Wastewater Treatment

7.1 bioinformatics and genome sequencing.

A computational approach is accessible in wastewater treatment. Several tools and techniques are in use such as, sequencing platforms (Hall, 2007 ; Marsh, 2007 ), metagenome sequencing strategies (Schloss & Handelsman, 2005 ; Schmeisser et al., 2007 ; Tringe et al., 2005 ), bioinformatics tools and techniques (Chen & Pachter, 2005 ; Foerstner et al., 2006 ; Raes et al., 2007 ), and the genome analysis of complex microbial communities (Fig. 4 ). Most of the biological database contains microorganisms and taxonomical information. Thus, these can provide extensive details and supports for further utilization in wastewater treatment–related research and development (Siezen & Galardini, 2008 ). Balcom et al. ( 2016 ) explored that the microbial population residing in the plant roots immersed in the wastewater of an ecological WWTP and showed the evidence of the capacity for micro-pollutant biodegradation using whole metagenome sequencing (WMS). Similarly, Kumar et al. ( 2016 ) revealed that bioremediation of highly polluted wastewater from textile dyes by two novel strains were found to highly decolorize Joyfix Red. They were identified as Lysinibacillus sphaericus (KF032717) and Aeromonas hydrophila (KF032718) through 16S rDNA analysis. More recently, Leddy et al. ( 2018 ) reported that research scientists are making strides to advance the safety and application of potable water reuse with metagenomics for water quality analysis. The application of the bio-computational approach has also been implemented in the advancements of wastewater treatment and disease detection.

A schematic showing the overall conceptual framework on which depicting the computational approach in wastewater treatment

7.2 Computational Fluid Dynamics in Wastewater Treatment

In recent years, computational fluid dynamics (CFD), a broadly used method, has been applied to biological wastewater treatment. It has exposed the inner flow state that is the hydraulic condition of a biological reactor (Peng et al., 2014 ). CFD is the application of powerful predictive modeling and simulation tools. It may calculate the multiple interactions between all the water quality and process design parameters. CFD modeling tools have already been widely used in other industries, but their application in the water industry is quite recent. CFD modeling has great applications in water and wastewater treatment, where it mechanically works by using hydrodynamic and mass transfer performance of single or two-phase flow reactors (Do-Quang et al., 1998 ). The level of CFD’s capability varies between different process units. It has a high frequency of application in the areas of final sedimentation, activated sludge basin modeling, disinfection, and greater needs in primary sedimentation and anaerobic digestion (Samstag et al., 2016 ). Now, researchers are enhancing the CFD modeling with a developed 3D model of the anoxic zone to evaluate further hydrodynamic performance (Elshaw et al., 2016 ). The overall conceptual framework and the applications of the computational approach in wastewater treatment are presented in Fig. 4 .

7.3 Computational Artificial Intelligence Approach in Wastewater Treatment

Several studies were obtained by researchers to implement computer-based artificial techniques, which provide fast and rapid automated monitoring of water quality tests such as BOD and COD. Recently, Nourani et al. ( 2018 ) explores the possibility of wastewater treatment plant by using three different kinds of artificial intelligence methods, i.e., feedforward neural network (FFNN), adaptive neuro-fuzzy inference system (ANFIS), and support vector machine (SVM). Several measurements were done in terms of effluent to tests BOD, COD, and total nitrogen in the Nicosia wastewater treatment plant (NWWTP) and reported high-performance efficiency of artificial intelligence (Nourani et al., 2018 ).

7.4 Remote sensing and Geographical Information System

Since the implementation of satellite technology, the initiation of new methods and tools became popular nowadays. The futuristic approach of remote sensing and GIS technology plays a crucial role in the identification and locating of the water polluted area through satellite imaginary and spatial data. GIS analysis may provide a quick and reasonable solution to develop atmospheric correction methods. Moreover, it provides a user-friendly environment, which may support complex spatial operations to get the best quality information on water quality parameters through remote sensing (Ramadas & Samantaray, 2018 ).

8 Applications of Treated Wastewater

8.1 scope in crop irrigation.

Several studies have assessed the impact of the reuse of recycled/treated wastewater in major sectors. These are agriculture, landscapes, public parks, golf course irrigation, cooling water for power plants and oil refineries, processing water for mills, plants, toilet flushing, dust control, construction activities, concrete mixing, and artificial lakes (Table 5 ). Although the treated wastewater after secondary treatment is adequate for reuse since the level of heavy metals in the effluent is similar to that in nature (Ayers & Westcot, 1985 ), experimental evidences have been found and evaluated the effects of irrigation with treated wastewater on soil fertility and chemical characteristics, where it has been concluded that secondary treated wastewater can improve soil fertility parameters (Mohammad & Mazahreh, 2003 ). The proposed model (Fig. 3 ) is tested partially previously at a laboratory scale by treating the wastewater (from sewage, sugar, and paper industry) in an ultrasonic bath (Kesari et al., 2011a , b ; Kesari & Behari, 2008 ; Kumar et al., 2010 ). Advancing it with ultraviolet and ozone treatment has modified this in the proposed model. A recent study shows that the treated water passed quality measures suited for crop irrigation (Bhatnagar et al., 2016 ). In Fig. 3 , a model is proposed including all three (UV, US, nanoparticle, and ozone) techniques, which have been tested individually as well as in combination (US and nanoparticle) (Kesari et al., 2011a , b ) to obtain the highest water quality standards acceptable for irrigation and even drinking purposes.

A wastewater-irrigated field is a major source of essential and non-essential metals contaminants such as lead, copper, zinc, boron, cobalt, chromium, arsenic, molybdenum, and manganese. While crops need some of these, the others are non-essential metals, toxic to plants, animals, and humans. Kanwar and Sandha ( 2000 ) reported that heavy metal concentrations in plants grown in wastewater-irrigated soils were significantly higher than in plants grown in the reference soil in their study. Yaqub et al. ( 2012 ) suggest that the use of US is very effective in removing heavy or toxic metals and organic pollutants from industrial wastewater. However, it has been also observed that the metals were removed efficiently, when UV light was combined with ozone (Samarghandi et al., 2007 ). Ozone exposure is a potent method for the removal of metal or toxic compounds from wastewater as also reported earlier (Park et al., 2008 ). Application of US, UV, and O 3 in combination lead to the formation of reactive oxygen species (ROS) that oxidize certain organics, metal ions and kill pathogens. In the process of advanced oxidizing process (AOP) primarily oxidants, electricity, light, catalysts etc. are implied to produce extremely reactive free radicals (such as OH) for the breakdown of organic matters (Oturan & Aaron, 2014 ). Among the other AOPs, ozone oxidization process is more promising and effective for the decomposition of complex organic contaminants (Xu et al., 2020 ). Ozone oxidizes the heavy metal to their higher oxidation state to form metallic oxides or hydroxides in which they generally form limited soluble oxides and gets precipitated, which are easy to be filtered by filtration process. Ozone oxidization found to be efficient for the removal of heavy metals like cadmium, chromium, cobalt, copper, lead, manganese, nickel, and zinc from the water source (Upadhyay & Srivastava, 2005 ). Ultrasonic-treated sludge leads to the disintegration of biological cells and kills bacteria in treated wastewater (Kesari, Kumar, et al., 2011a ; Kesari, Verma, & Behari, 2011b ). This has been found that combined treatment with ultrasound and nanoparticles is more effective (Kesari, Kumar, et al., 2011a ). Ultrasonication has the physical effects of cavitation inactivate and lyse bacteria (Broekman et al., 2010 ). The induced effect of US, US, or ozone may destroy the pathogens and especially during ultrasound irradiation including free-radical attack, hydroxyl radical attack, and physical disruption of cell membranes (Kesari, Kumar, et al., 2011a ; Phull et al., 1997 ; Scherba et al., 1991 ).

8.2 Energy and Economy Management

Municipal wastewater treatment plants play a major role in wastewater sanitation and public health protection. However, domestic wastewater has been considered as a resource or valuable products instead of waste, because it has been playing a significant role in the recovery of energy and resource for the plant-fertilizing nutrients like phosphorus and nitrogen. Use of domestic wastewater is widely accepted for the crop irrigation in agriculture and industrial consumption to avoid the water crisis. It has also been found as a source of energy through the anaerobic conversion of the organic content of wastewater into methane gas. However, most of the wastewater treatment plants are using traditional technology, as anaerobic sludge digestion to treat wastewater, which results in more consumption of energy. Therefore, through these conventional technologies, only a fraction of the energy of wastewater has been captured. In order to solve these issues, the next generation of municipal wastewater treatment plants is approaching total retrieval of the energy potential of water and nutrients, mostly nitrogen and phosphorus. These plants also play an important role in the removal and recovery of emerging pollutants and valuable products of different nature like heavy and radioactive metals, fertilizers hormones, and pharma compounds. Moreover, there are still few possibilities of improvement in wastewater treatment plants to retrieve and reuse of these compounds. There are several methods under development to convert the organic matter into bioenergy such as biohydrogen, biodiesel, bioethanol, and microbial fuel cell. These methods are capable to produce electricity from wastewater but still need an appropriate development. Energy development through wastewater is a great driver to regulate the wastewater energy because it produces 10 times more energy than chemical, thermal, and hydraulic forms. Vermicomposting can be utilized for stabilization of sludge from the wastewater treatment plant. Kesari and Jamal ( 2017 ) have reported the significant, economical, and ecofriendly role of the vermicomposting method for the conversion of solid waste materials into organic fertilizers as presented in Fig. 5 . Solid waste may come from several sources of municipal and industrial sludge, for example, textile industry, paper mill, sugarcane, pulp industry, dairy, and intensively housed livestock. These solid wastes or sewage sludges have been treated successfully by composting and/or vermicomposting (Contreras-Ramos et al., 2005 ; Elvira et al., 1998 ; Fraser-Quick, 2002 ; Ndegwa & Thompson, 2001 ; Sinha et al., 2010 ) Although collection of solid wastes materials from sewage or wastewater and further drying is one of the important concerns, processing of dried municipal sewage sludge (Contreras-Ramos et al., 2005 ) and management (Ayilara et al., 2020 ) for vermicomposting could be possible way of generating organic fertilizers for future research. Vermicomposting of household solid wastes, agriculture wastes, or pulp and sugarcane industry wastes shows greater potential as fertilizer for higher crop yielding (Bhatnagar et al., 2016 ; Kesari & Jamal, 2017 ). The higher amount of solid waste comes from agricultural land and instead of utilizing it, this biomass is processed by burning, which causes severe diseases (Kesari & Jamal, 2017 ). Figure 3 shows the proper utilization of solid waste after removal from wastewater; however, Fig. 5 showing greater possibility in fertilizer conversion which has also been discussed in detail elsewhere (Bhatnagar et al., 2016 ; Nagavallemma et al., 2006 )

Energy production through wastewater (reproduced from Bhatnagar et al., 2016 ; Kesari & Jamal, 2017 )

9 Conclusions and future perspectives

In this paper, we have reviewed environmental and public health issues associated with the use of untreated wastewater in agriculture. We have focused on the current state of affairs concerning the wastewater treatment model and computational approach. Given the dire need for holistic approaches for cultivation, we proposed the ideas to tackle the issues related to wastewater treatment and the reuse potential of the treated water. Water resources are under threat because of the growing population. Increasing generation of wastewater (municipal, industrial, and agricultural) in developing countries especially in India and other Asian countries has the potential to serve as an alternative of freshwater resources for reuse in rice agriculture, provide appropriate treatment, and distribution measures are adopted. Wastewater treatment is one of the big challenges for many countries because increasing levels of undesired or unknown pollutants are very harmful to health as well as environment. Therefore, this review explores the ideas based on current and future research. Wastewater treatment includes very traditional methods by following primary, secondary, and tertiary treatment procedures, but the implementation of advanced techniques is always giving us a big possibility of good water quality. In this paper, we have proposed combined methods for the wastewater treatment, where the concept of the proposed model works on the various types of wastewater effluents. The proposed model not only useful for wastewater treatment but also for the utilization of solid wastes as fertilizer. An appropriate method for the treatment of wastewater and further utilization for drinking water is the main futuristic outcome. It is also highly recommendable to follow the standard methods and available guidelines provided WHO. In this paper, the proposed role of the computational model, i.e., artificial intelligence, fluid dynamics, and GIS, in wastewater treatment could be useful in future studies. In this review, health concerns associated with wastewater irrigation for farmers and irrigated crops consumers have been discussed.

The crisis of freshwater is one of the growing concerns in the twenty-first century. Globaly, about 330 km 3 of municipal wastewater is generated annually (Hernández-Sancho et al., 2015 ). This data provides a better understanding of why the reuse of treated wastewater is important to solve the issues of the water crisis. The use of treated wastewater (industrial or municipal wastewater or Seawater) for irrigation has a better future for the fulfillment of water demand. Currently, in developing countries, farmers are using wastewater directly for irrigation, which may cause several health issues for both farmers and consumers (crops or vegetables). Therefore, it is very imperative to implement standard and advanced methods for wastewater treatment. A local assessment of the environmental and health impacts of wastewater irrigation is required because most of the developed and developing countries are not using the proper guidelines. Therefore, it is highly required to establish concrete policies and practices to encourage safe water reuse to take advantage of all its potential benefits in agriculture and for farmers.

Abdel-Fatah, M. A. (2018). Nanofiltration systems and applications in wastewater treatment: Review article. Ain Shams Engineering Journal, 9 , 3077–3092.

Google Scholar  

Adegoke, A. A., Faleye, A. C., Singh, G., & Stenström, T. A. (2016). Antibiotic resistant superbugs: Assessment of the interrelationship of occurrence in clinical settings and environmental niches. Molecules, 22 , E29.

Adegoke, A. A., Stenström, T. A., & Okoh, A. I. (2017). Stenotrophomonas maltophilia as an emerging ubiquitous pathogen: Looking beyond contemporary antibiotic therapy. Frontiers in Microbiology, 8 , 2276.

Adegoke, A. A., Amoah, I. D., Stenström, T. A., Verbyla, M. E., & Mihelcic, J. R. (2018). Epidemiological evidence and health risks associated with agricultural reuse of partially treated and untreated wastewater: A review. Frontiers in Public Health, 6 , 337.

Adewumia, J. R., Ilemobadea, A. A., & Vanzyl, J. E. (2010). Treated wastewater reuse in South Africa: Overview, potential, and challenges. Resources, Conservation and Recycling, 55 , 221–231.

Agoro, M. A., Adeniji, A. O., Adefisoye, M. A., & Okoh, O. O. (2020). Heavy metals in wastewater and sewage sludge from selected municipal treatment plants in Eastern Cape Province, South Africa. Water, 12 , 2746.

CAS   Google Scholar  

Akasaka, T., & Watari, F. (2009). Capture of bacteria by flexible carbon nanotubes. Acta Biomaterialia, 5 , 607–612.

Akponikpe, P., Wima, K., Yakouba, H., & Mermoud, A. (2011). Reuse of domestic wastewater treated in macrophyte ponds to irrigate tomato and eggplants in semi-arid West-Africa: Benefits and risks. Agricultural Water Management, 98 , 834–840.

Alghobar, M. A., Ramachandra, L., & Suresha, S. (2014). Effect of sewage water irrigation on soil properties and evaluation of the accumulation of elements in Grass crop in Mysore city, Karnataka, India. American Journal of Environmental Protection, 3 , 283–291.

Al-Nakshabandi, G. A., Saqqar, M. M., Shatanawi, M. R., Fayyad, M., & Al-Horani, H. (1997). Some environmental problems associated with the use of treated wastewater for irrigation in Jordan. Agricultural Water Management, 34 , 81–94.

Amabilis-Sosa, L. E., Vázquez-López, E., García Rojas, J. L., Roé-Sosa, A., & Moeller-Chávez, G. E. (2018). Efficient bacteria inactivation by ultrasound in municipal wastewater. Environments, 5 , 47.

Amoah, I. D., Adegoke, A. A., & Stenström, T. A. (2018). Soil-transmitted helminth infections associated with wastewater and sludge reuse: A review of current evidence. Tropical Medicine & International Health, 23 (7), 692–703.

Anastasi, A., Spina, F., Prigione, V., Tigini, V., Giansanti, P., & Varese, G. C. (2010). Scale-up of a bioprocess for textile wastewater treatment using Bjerkandera adusta. Bioresource Technology, 101 , 3067–3075.

Angelakis, A., & Snyder, S. (2015). Wastewater treatment and reuse: Past, present, and future. Water, 7 , 87–95.

Angelakis, A. N., Marecos do Monte, M. H. F., Bontoux, L., & Asano, T. (1999). The status of wastewater reuse practice in the Mediterranean basin: Need for guidelines. Water Research, 33 , 2201–2217.

Asaithambi, P., & Matheswaran, M. (2016). Electrochemical treatment of simulated sugar industrial effluent: Optimization and modeling using a response surface methodology. Arabian Journal of Chemistry, 9 , S981–S987.

Ayers, R. S., & Westcot, D. W. (1985). Water quality for agriculture; Food and Agriculture Organization of the United . Nations.

Ayilara, M. S., Olanrewaju, O. S., Babalola, O. O., & Odeyemi, O. (2020). Waste management through composting: Challenges and potentials. Sustainability, 12 , 4456.

Azevedo, B. F., Furieri, L. B., Peçanha, F. M., Wiggers, G. A., Vassallo, P. F., Simões, M. R., et al. (2014). Toxic effects of mercury on the cardiovascular and central nervous systems. Journal of Preventive Medicine and Public Health, 47 , 74–83.

Aziz, F., & Farissi, M. (2014). Reuse of treated wastewater in agriculture: solving water deficit problems in arid areas. Annals of West University of Timişoara Series of Biology, 17 , 95–110.

Balcom, I. N., Driscoll, H., Vincent, J., & Leduc, M. (2016). Metagenomic analysis of an ecological wastewater treatment plant’s microbial communities and their potential to metabolize pharmaceuticals. F1000 Research, 5 , 1881.

Balkhair, K. S. (2016a). Microbial contamination of vegetable crop and soil profile in arid regions under controlled application of domestic wastewater. Saudi Journal of Biological Sciences, 23 (1), S83–S92.

Balkhair, K. S. (2016b). Impact of treated wastewater on soil hydraulic properties and vegetable crop under irrigation with treated wastewater, field study and statistical analysis. Journal of Environmental Biology, 37 (5), 1143–1152.

Balkhair, K. S., & Ashraf, M. A. (2016). Field accumulation risks of heavy metals in soil and vegetable crop irrigated with sewage water in western region of Saudi Arabia. Saudi Journal of Biological Science, 23 , S32–S44.

Behling, E., Diaz, A., Colina, G., Herrera, M., Gutierrez, E., Chacin, E., et al. (1996). Domestic wastewater treatment using a UASB reactor. Bioresource Technology, 61 , 239–245.

Bent, S., & Bohm, K. (1995). Copper induced liver cirrhosis in a 13-month-old boy. Gesundheitswesen (health system in German), 57 , 667–669.

Bhatnagar, A., Kesari, K. K., & Shurpali, N. (2016). Multidisciplinary approaches to handling wastes in sugar industries. Water, Air, & Soil Pollution, 11 , 1–30.

Blume, T., & Neis, U. (2004). Improved wastewater disinfection by ultrasonic pre-treatment. Ultrasonics Sonochemistry, 11 , 333–336.

Bolong, N., Ismail, A. F., Salim, M. R., & Matsuura, T. (2009). A review of the effects of emerging contaminants in wastewater and options for their removal. Desalination, 239 , 229–246.

Bonefeld-Jorgensen, E. C., Long, M., Bossi, R., Ayotte, P., Asmund, G., Kruger, T., et al. (2011). Perfluorinated compounds are related to breast cancer risk in Greenlandic Inuit: A case control study. Environmental Health Perspectives, 10 , 88–95.

Börjesson, S., Melin, S., Matussek, A., & Lindgren, P. E. (2009). A seasonal study of the mecA gene and Staphylococcus aureus including methicillin-resistant S. aureus in a municipal wastewater treatment plant. Water Research, 43 , 925–932.

Bos, R., Carr, R., & Keraita, B. (2010). Assessing and mitigating wastewater-related health risks in low income countries: An introduction. In P. Drechsel, C. A. Scott, L. Raschid-Sally, M. Redwood, & A. Bahri (Eds.), In: Wastewater irrigation and health: Assessing and mitigating risk in low-income countries (pp. 29–47). Earthscan.

Briffa, J., Sinagra, E., & Blundell, R. (2020). Heavy metal pollution in the environment and their toxicological effects on humans. Heliyon, 6 , e04691.

Brissaud, F. (2008). Criteria for water recycling and reuse in the Mediterranean countries. Desalination, 218 , 24–33.

Broekman, S., Pohlmann, O., Beardwood, E. S., & de Meulenaer, E. C. (2010). Ultrasonic treatment for microbiological control of water systems. Ultrasonics Sonochemistry, 17 , 1041–1048.

Brumer, L. (2000). Use of aquatic macrophytes to improve the quality of effluents after chlorination. Ph.D. Dissertation, Technion Israel Institute of Technology, Haifa.

Busgang, A., Friedler, E., Gilboa, Y., & Gross, A. (2018). Quantitative microbial risk analysis for various bacterial exposure scenarios involving greywater reuse for irrigation. Water, 10 , 413.

Caplin, J. L., Hanlon, G. W., & Taylor, H. D. (2008). Presence of vancomycin and ampicillin-resistant Enterococcus faecium of epidemic clonal complex-17 in wastewaters from the south coast of England. Environmental Microbiology, 10 , 885–892.

Carey, C., Lee, H., & Trevors, J. (2004). Biology, persistence and detection of Cryptosporidium parvum and Cryptosporidium homynis oocyst. Water Research, 38 , 818–868.

Carr, R. (2005). WHO guidelines for safe wastewater use-more than just numbers. Irrigation and Drainage, 54 , 103–111.

CCREM. (1987). Canadian Water Quality Guidelines . Prepared by the Task Force on Water Quality Guidelines of the Canadian Council of Resource and Environment Ministers.

Chang, J. S., Chou, C., & Chen, S. Y. (2001). Decolorization of azo dyes with immobilized Pseudomonas luteola. Process Biochemistry, 36 , 757–763.

Chaoua, S., Boussaa, S., Gharmali, A. E., & Boumezzough, A. (2019). Impact of irrigation with wastewater on accumulation of heavy metals in soil and crops in the region of Marrakech in Morocco. Journal of the Saudi Society of Agricultural Sciences, 18, 429–436.

Chen, K., & Pachter, L. (2005). Bioinformatics for whole-genome shotgun sequencing of microbial communities. PLoS Computational Biology, 1 , 106–112.

Chen, W., Lu, S., Pan, N., & Jiao, W. (2013). Impacts of long-term reclaimed water irrigation on soil salinity accumulation in urban green land in Beijing. Water Resources Research, 49 , 7401–7410.

City of Cape Town (CoCT). 2007 Water services Development plan 2007/2008. www.capetown.gov.za/en/Water/WaterservicesDevPlan/Pages/WaterServDevPlan200708.aspx Accessed 12 June 2008.

Clemmens, A. J., Allen, R. G., & Burt, C. M. (2008). Technical concepts related to conservation of irrigation and rainwater in agricultural systems. Water Resources Research, 44 , 1–16.

Coleman, J., Hench, K., Garbutt, K., Sexstone, A., Bissonnette, B., & Skousen, J. (2001). Treatment of domestic wastewater by three plant species in constructed wetlands. Water, Air, and Soil Pollution, 3 , 283–295.

Contreras, J. D., Meza, R., Siebe, C., Rodríguez-Dozal, S., López-Vidal, Y. A., Castillo-Rojas, G., et al. (2017). Health risks from exposure to untreated wastewater used for irrigation in the Mezquital Valley, Mexico: A 25-year update. Water Research, 123 , 834–850.

Contreras-Ramos, S. M., Escamilla-Silva, E. M., & Dendooven, L. (2005). Vermicomposting of biosolids with cow manure and wheat straw. Biological Fertility of Soils, 41 , 190–198.

Craun, M. F., Craun, G. F., Calderon, R. L., & Beach, M. J. (2006). Waterborne outbreaks in the United States. Journal of Water and Health, 4 (suppl 2), 19–30.

Craun, G. F., Brunkard, J. M., Yoder, J. S., Roberts, V. A., Carpenter, J., Wade, T., et al. (2010). Causes of outbreaks associated with drinking water in the United States from 1971 to 2006. Clinical Microbiology Reviews, 23 , 507–528.

Dang, Q., Tan, W., Zhao, X., Li, D., Li, Y., Yang, T., et al. (2019). Linking the response of soil microbial community structure in soils to long-term wastewater irrigation and soil depth. The Science of the total environment, 688, 26–36.

Delgado, A., Anselmo, A. M., & Novais, J. M. (1998). Heavy metal biosorption by dried powdered mycelium of Fusarium Flocci ferum. Water Environmental Research, 70 , 370.

Dewitt, J. C., Peden-Adams, M. M., Keller, J. M., & Germolec, D. R. (2012). Immunotoxicity of perfluorinated compounds: Recent developments. Toxicologic Pathology, 40 , 300–311.

Dickin, S. K., Schuster-Wallace, C. J., Qadir, M., & Pizzacalla, K. (2016). A review of health risks and pathways for exposure to wastewater use in agriculture. Environmental Health Perspectives, 124 , 900–909.

Do-Quang, Z., Cockx, A., Line, A., & Roustan, M. (1998). Computational fluid dynamics applied to water and wastewater treatment facility modeling. Environmental Engineering and Policy, 1 , 137–147.

Drechsel, P., Scott, A., Sally, R., Redwood, M., Bachir, A. (2010). Wastewater Irrigation and Health: Assessing and Mitigating Risk in Low-Income Countries; International Water Management Institute, Ed.; Earthscan: London, UK.

Duan, J. J., Zhao, J. N., Xue, L. H., & Yang, L. Z. (2016). Nutrient removal of a floating plant system receiving low- pollution wastewater: Effects of plant species and influent concentration. IOP Conference Series: Earth and Environmental Science, 41 , 1.

Duan, B., Zhang, W., Zheng, H., Wu, C., Zhang, Q., & Bu, Y. (2017). Comparison of health risk assessments of heavy metals and as in sewage sludge from wastewater treatment plants (WWTPs) for adults and children in the Urban district of Taiyuan, China. International Journal of Environmental Research and Public Health, 14 , 1194.

Duncan, M. (2009). Waste stabilization ponds: Past, present and future. Desalination and Water Treatment, 4 , 85–88.

Ecosse, D. (2001). Alternative techniques in order to meet the shortage of water in the world. Mem DESS Quality and Management of Water, Fac. Science, Amiens 62.

EEA CSI (2018). https://www.eea.europa.eu/themes/water/water-resources/water-use-by-sectors . Accessed 3 Oct 2019.

EPA (Environmental Protection Agency) (2002).National Recommended Water Quality Criteria: 2002. Office of Water, Office of Science and Technology. EPA-822-R-02-047.

Elshaw, A., Hassan, N. M. S., Khan, M. M. K. (2016). CFD modelling and optimisation of a wastewater treatment plant bioreactor—A case study. In Proceedings of the 2016 3rd Asia-Pacific World Congress on Computer science and Engineering (APWC on CSE), 232–239 https://doi.org/10.1109/APWC-on-CSE.2016.046 .

Elvira, C., Sampedro, L., Benitez, E., & Nogales, R. (1998). Vermicomposting of sludges from paper mills and dairy industries with Elsenia anderi. A pilot scale study. Journal of Bioresource Technology, 63 , 205–211.

Falkenberg, T., & Saxena, D. (2018). Impact of wastewater-irrigated urban agriculture on diarrhea incidence in Ahmedabad, India. Indian Journal of Community Medicine, 43 , 102–106.

FAO, (1985) Water Quality for Agriculture. Irrigation and Drainage Paper No. 29, Rev. 1. Food and Agriculture Organization of the United Nations, Rome.

Fazeli, M. S., Khosravan, F., Hossini, M., Sathyanarayan, S., & Satish, P. N. (1998). Enrichment of heavy metals in paddy crops irrigated by paper mill effluents near Nanjangud, Mysore District, Karnataka, India. Environmental Geology, 34 , 297–302.

FEPA. (1991). Proposed National Water Quality Standards . Federal Environmental Protection Agency.

Foerstner, K. U., Von-Mering, C., & Bork, P. (2006). Comparative analysis of environmental sequences: potential and challenges. Philosophical transactions of the Royal Society of London Series B, Biological sciences, 361 , 519–523.

Founou, R. C., Founou, L. L., & Essack, S. Y. (2017). Clinical and economic impact of antibiotic resistance in developing countries: A systematic review and meta-analysis. PLoS One, 12 , e0189621. https://doi.org/10.1371/journal.pone.0189621 .

Article   CAS   Google Scholar  

Fraser-Quick, G. (2002). Vermiculture – A sustainable total waste management solution. What’s New in Waste Management?, 4 , 13–16.

Freitas, F., Alves, V. D., Pais, J., Costa, N., Oliveira, C., & Mafra, L. (2009). Characterization of an extracellular polysaccharide produced by a Pseudomonas strain grown on glycerol. Bioresource Technology, 100 , 859–865.

Freitas, F., Alves, V. D., & Reis, M. A. (2011a). Advances in bacterial exopolysaccharides: From production to biotechnological applications. Trends in Biotechnology, 29 , 388–398.

Freitas, F., Alves, V. D., Torres, C. A., Cruz, M., Sousa, I., & Melo, M. J. (2011b). Fucose-containing exopolysaccharide produced by the newly isolated Enterobacter strain A47 DSM 23139. Carbohydrate Polymers, 83 , 159–165.

Frontistis, Z., Xekoukoulotakis, N. P., Hapeshi, E., Venieri, D., Fatta-Kassinos, D., & Mantzavinos, D. (2011). Fast degradation of estrogen hormones in environmental matrices by photo-Fenton oxidation under simulated solar radiation. Chemical Engineering Journal, 178 (15), 175–182.

Fukushima, M., Ishizaki, A., & Sakamoto, M. (1970). On distribution of heavy metals in rice field soil in the “Itai-itai” disease epidemic district. Japanese Journal of Hygiene, 24 , 526–535.

Gatta, G., Libutti, A., Gagliardi, A., Disciglio, G., Beneduce, L., d’Antuono, M., Rendina, M., & Tarantino, E. (2015a). Effects of treated agro-industrial wastewater irrigation on tomato processing quality. Italian Journal of Agronomy, 10 (2), 97–100.

Gatta, G., Libutti, A., Gagliardi, A., Beneduce, L., Borruso, L., Disciglio, G., & Tarantino, G. (2015b). Treated agro-industrial wastewater irrigation of tomato crop: Effects on qualitative/quantitative characteristics of production and microbiological properties of the soil. Agricultural Water Management, 149 , 33–43.

Gehrke, I., Geiser, A., & Somborn-Schulz, A. (2015). Innovations in nanotechnology for water treatment. Nanotechnology, Science and Applications, 8 , 1–17.

Genchi, G., Sinicropi, M. S., Lauria, G., Carocci, A., & Catalano, A. (2020). The effects of cadmium toxicity. International Journal of Environmental Research and Public Health, 17 , 3782.

Giddins, M. J., Macesic, N., Annavajhala, M. K., Stump, S., Khan, S., McConville, T. H., Mehta, M., Gomez-Simmonds, A., & Uhlemann, A. C. (2017). Successive emergence of ceftazidime-avibactam resistance through distinct genomic adaptations in bla(KPC-2)-harboring Klebsiella pneumoniae sequence type 307 isolates. Antimicrobial Agents and Chemotherapy, 62 , e02101–e02117.

Goel, J., Kadirvelu, K., Rajagopal, C., Kumar, G., & V. (2005). Removal of lead (II) by adsorption using treated granular activated carbon: Batch and column studies. Journal of Hazardous Materials, 125 (1-3), 211–220.

Goldstein, R. E. R. (2013). Antibiotic-resistant bacteria in wastewater and potential human exposure through wastewater reuse. PhD Dissertation, University of Maryland.

Gupta, P., & Diwan, B. (2017). Bacterial Exopolysaccharide mediated heavy metal removal: A review on biosynthesis, mechanism and remediation strategies. Biotechnology Reports, 13 , 58–71.

Gupta, S. K., Shin, H., Han, D., Hur, H. G., & Unno, T. (2018). Metagenomic analysis reveals the prevalence and persistence of antibiotic- and heavy metal-resistance genes in wastewater treatment. Plant Journal of Microbiology, 56 , 408–415.

GWI Global Water Intelligence. (2009). PUB study: Perspectives of water reuse . GWI Publishing.

Hall, N. (2007). Advanced sequencing technologies and their wider impact in microbiology. Journal of Experimental Biology, 210 , 1518–1525.

Halliwell, D. J., Barlow, K. M., & Nash, D. M. (2001). A review of the effects of wastewater sodium on soil physical properties and their implications for irrigation systems. Australian Journal of Soil Research, 39 , 1259–1267.

He, Y., Yuan, Q., Mathieu, J., Stadler, L., Senehi, N., Sun, R., & Alvarez, P. J. J. (2020). Antibiotic resistance genes from livestock waste: Occurrence, dissemination and treatment. npj Clean Water, 3 , 4.

Herc, E. S., Kauffman, C. A., Marini, B. L., Perissinotti, A. J., & Miceli, M. H. (2017). Daptomycin nonsusceptible vancomycin resistant Enterococcus bloodstream infections in patients with hematological malignancies: Risk factors and outcomes. Leukemia & Lymphoma, 58 , 2852–2858.

Hernández-Sancho, F., Lamizana-Diallo, B., Mateo-Sagasta, J., & Qadeer, M. (2015). Economic valuation of wastewater –The cost of action and the cost of no action . United Nations Environment Programme.

Hesnawi, R., Dahmani, K., Al-Swayah, A., Mohamed, S., & Mohammed, S. A. (2014). Biodegradation of municipal wastewater with local and commercial bacteria. Procedia Engineering, 70 , 810–814.

Hoekstra, A. Y., & Mekonnen, M. M. (2012). The water footprint of humanity. Proceedings of the National Academy of Sciences, 109 , 3232–3237.

Hua, I., & Thompson, J. E. (2000). Inactivation of E. coli by sonication at discrete ultrasonic frequencies. Water Research, 34 , 3888–3893.

Hussain, A., Priyadarshi, M., & Dubey, S. (2019). Experimental study on accumulation of heavy metals in vegetables irrigated with treated wastewater. Applied Water Science, 9 , 122.

Icgen, B., & Yilmaz, F. (2014). Co-occurrence of antibiotic and heavy metal resistance in Kizilirmak River isolates. Bulletin of Environmental Contamination and Toxicology, 93 , 735–743.

Iguchi, S., Mizutani, T., Hiramatsu, K., & Kikuchi, K. (2016). Rapid acquisition of linezolid resistance in methicillin-resistant Staphylococcus aureus: Role of hypermutation and homologous recombination. PLoS One, 11 , e0155512.

Indiana State Department of Health, 2009. Diseases Involving Sewage. https://www.in.gov/isdh/22963.htm

Inoue, Y., Hoshino, M., Takahashi, H., Noguchi, T., Murata, T., & Kanzaki, Y. (2002). Bactericidal activity of Ag-zeolite mediated by reactive oxygen species under aerated conditions. Journal of Inorganic Biochemistry, 92 , 37–42.

Jacquez, R. B., Walner, H. Z. (1985). Combining nutrient removal with protein synthesis using a water hyacinth-freshwater prawn polyculture wastewater treatment system. New Mexico Water Resources Research Institute . 92.

Jaishankar, M., Tseten, T., Anbalagan, N., Mathew, B. B., & Beeregowda, K. N. (2014). Toxicity, mechanism and health effects of some heavy metals. Interdisciplinary Toxicology, 7 (2), 60–72.

Jarup, L. (2003). Hazards of heavy metal contamination. British Medical Bulletin, 68 , 167–182.

Jeong, H., Kim, H., & Jang, J. (2016). Irrigation water quality standards for indirect wastewater reuse in agriculture: A contribution toward sustainable wastewater reuse in South Korea. Water, 8 , 169.

Jia, S., Zhang, X. (2020). Biological HRPs in wastewater. In High-risk pollutants in wastewater. Eds. Ren, H. and Zhang, X. 41-67.

Jiménez, B., & Asano, T. (2008). Water reclamation and reuse around the world. In B. Jiménez & T. Asano (Eds.), In: Water reuse: An International Survey of Current Practice, Issues and Needs (pp. 3–26). IWA Publishing .

Jindal, A., Kamat, S. (2011). Water recycling and reuse for domestic and industrial sectors. Chemical Engineering World , 52-62.

Jyothi, N.R. (2020). Heavy metal sources and their effects on human health, heavy metals - Their environmental impacts and mitigation. Ed. Nazal, M. 95370.

Jyothi, N.R. and Farook, N.A.M. (2020). Mercury toxicity in public health, Heavy Metal Toxicity in Public Health. 1-12.

Jyoti, K. K., & Pandit, A. B. (2004). Ozone and cavitation for water disinfection. Biochemical Engineering Journal, 38 , 2249–2258.

Kalavrouziotis, I. K., Kokkinos, P., Oron, G., Fatone, F., Bolzonella, D., Vatyliotou, M., et al. (2015). Current status in wastewater treatment, reuse and research in some mediterranean countries. Desalination and Water Treatment, 53 , 2015–2030.

Kanwar, J., & Sandha, M. (2000). Waste water pollution injury to vegetable crops: A review. Agricultural Research Communication Centre, India, 21 , 133–136.

Katsoyiannis, I. A., Gkotsis, P., Castellana, M., Cartechini, F., & Zouboulis, A. I. (2017). Production of demineralized water for use in thermal power stations by advanced treatment of secondary wastewater effluent. Journal of Environmental Management, 1 (190), 132–139.

Kenny, J. F., Barber, N. L., Hutson, S. S., Linsey, K. S., Lovelace, J. K., & Maupin, M. A. (2009). Estimated use of water in the United States in 2005. U.S. Geological Survey Circular, 1344 , 52.

Kesari, K. K., & Behari, J. (2008). Ultrasonic impact on bacterial population in sewage sample. International Journal of Environment and Waste Management, 2 , 233–244.

Kesari, K. K., Jamal, Q. M. S. (2017). Review Processing, properties and applications of agricultural solid waste: Effect of an open burning in environmental toxicology. In: Kesari K. (eds) Perspectives in Environmental Toxicology. Environmental Science and Engineering . Springer, Cham. Chapter 8:161-181.

Kesari, K. K., Kumar, S., Verma, H. N., & Behari, J. (2011a). Influence of ultrasonic treatment in sewage sludge. Hydrology: Current Research, 2 , 115.

Kesari, K. K., Verma, H. N., & Behari, J. (2011b). Physical methods in wastewater treatment. International Journal of Environmental Technology and Management, 14 , 43–66.

Khaskhoussy, K., Kahlaoui, B., Messoudi, N. B., Jozdan, O., Dakheel, A., & Hachicha, M. (2015). Effect of treated wastewater irrigation on heavy metals distribution in a Tunisian soil. Engineering Technology and Applied Science Research, 5 , 805–810.

Kim, S. Y., Kim, J. H., Kim, C. J., & Oh, D. K. (1996). Metal adsorption of the polysaccharide produced from Methylobacterium organophilum. Biotechnology Letters, 18 , 1161–1164.

Kim, B. H., Kang, Z., Ramanan, R., Choi, J. E., Cho, D. H., Oh, H. M., et al. (2014). Nutrient removal and biofuel production in high rate algal pond using real municipal wastewater. Journal of Microbiology and Biotechnology, 24 , 1123–1132.

Kinuthia, G. K., Ngure, V., Beti, D., Lugalia, R., Wangila, A., & Kamau, L. (2020). Levels of heavy metals in wastewater and soil samples from open drainage channels in Nairobi, Kenya: community health implication. Scientific Reports, 10 , 8434 .

Kocabas, Z. O., Aciksoz, B., Yurum, Y. (2012). Binding mechanisms of As(III) on activated carbon/titanium dioxide nanocomposites: a potential method for arsenic removal from water, MRS online proceedings library. Published online by Cambridge University Press 1449.

König, M., Escher, B. I., Neale, P. A., Krauss, M., Hilscherová, K., Novák, J., et al. (2017). Impact of untreated wastewater on a major European river evaluated with a combination of in vitro bioassays and chemical analysis. Environmental Pollution, 220 (Part B), 1220–1230.

Kumar, R., & Chawla, J. (2014). Removal of cadmium ion from water/wastewater by nano-metal oxides. Water Quality Exposure and Health, 5 , 4.

Kumar, M., Kesari, K. K., & Behari, J. (2010). Low frequency ultrasonic irradiation of activated sludge. International Journal of Environment and Pollution, 43 , 52–65.

Kumar, S. S., Shantkriti, S., Muruganandham, T., Murugesh, E., Rane, N., & Govindwar, N. P. (2016). Bioinformatics aided microbial approach for bioremediation of wastewater containing textile dyes. Ecological Informatics, 31 , 112–121.

Kumar, A., Ali, M., Kumar, R., Kumar, M., Sagar, P., Pandey, R. K., et al. (2021). Arsenic exposure in Indo Gangetic plains of Bihar causing increased cancer risk. Scientific Reports, 11 , 2376.

Leddy, M. B., Plumlee, M. H., Kantor, R. S., Nelson, K. L., Miller, S. E., Kennedy, L. C., et al. (2018). High-throughput DNA sequencing to profile microbial water quality of potable reuse. Water online, 1-4.

Lee, I., & Viberg, H. (2013). A single neonatal exposure to perfluorohexane sulfonate (PFHxS) affects the levels of important neuroproteins in the developing mouse brain. Neurotoxicology, 37 , 190–196.

Libutti, A., Gatta, G., Gagliardi, A., Vergine, P., Pollice, A., Beneduce, L., Disciglio, G., & Tarantino, E. (2018). Agro-industrial wastewater reuse for irrigation of a vegetable crop succession under Mediterranean conditions. Agricultural Water Management, 196 , 1–14.

Liu, J., Ma, Y., Xu, T., & Shao, G. (2010). Preparation of zwitterionic hybrid polymer and its application for the removal of heavy metal ions from water. Journal of Hazardous Materials, 178 , 1021–1029.

Lv, L., Yu, X., Xu, Q., & Ye, C. (2015). Induction of bacterial antibiotic resistance by mutagenic halogenated nitrogenous disinfection byproducts. Environmental Pollution, 205 , 291–298.

Madsen, H., Poultsen, L., & Grandjean, P. (1990). Risk of high copper content in drinking water. Ugeskr Laeger (Journal of the Danish Medical Association), 152 (25), 1806–1809.

Mahendran, R., Ramli, N. H., & Abdurrahman, H. N. (2014). Study the effect of using ultrasonic membrane anaerobic system in treating sugarcane waste and methane gas production. International Journal of Research in Engineering and Technology, 3 , 299–303.

Mahfooz, Y., Yasar, A., Guijian, L., Islam, Q. U., Akhtar, A. B. T., Rasheed, R., Irshad, S., & Naeem, U. (2020). Critical risk analysis of metals toxicity in wastewater irrigated soil and crops: a study of a semi-arid developing region. Scientific Reports, 10 , 12845.

Mahmood, A., & Malik, R. N. (2014). Human health risk assessment of heavy metals via consumption of contaminated vegetables collected from different irrigation sources in Lahore. Pakistan, Arabian Journal of Chemistry, 7 (1), 91–99.

Mañas, P., Castro, E., & Heras, J. (2009). Irrigation with treated wastewater: effects on soil, lettuce (Lactuca sativa L.) crop and dynamics of microorganisms. Journal of Environmental Science and Health, 44 , 1261.

Marchal, M., Briandet, R., Koechler, S., Kammerer, B., & Bertin, P. N. (2010). Effect of arsenite on swimming motility delays surface colonization in Herminiimona sarsenicoxydans. Microbiology, 156 , 2336–2342.

Marcussen, H., Holm, P. E., Ha, L. T., & Dalsgaard, A. (2007). Food safety aspects of toxic element accumulation in fish from wastewater-feed ponds in Hanoi, Vietnam . Tropical Medicine & International Health, 12 , 34–39.

Marsh, S. (2007). Pyrosequencing applications. Methods in Molecular Biology, 373 , 15–24.

Meehan, C., Bjourson, A. J., & McMullan, G. (2001). Paeni bacillus azoreducens sp. nov., a synthetic azo dye decolorizing bacterium from industrial wastewater. International Journal of Systematic and Evolutionary Microbiology, 51 , 1681–1685.

Mehmood, A., Mirza, A. S., Choudhary, M. A., Kim, K. H., Raza, W., Raza, N., Lee, S. S., Zhang, M., Lee, J. H., & Sarfraz, M. (2019). Spatial distribution of heavy metals in crops in a wastewater irrigated zone and health risk assessment. Environmental Research, 168 , 382–388.

Melanta, S. (2008). Aquatic bacteria removal using carbon nanotubes. Biological and Agricultural Engineering Undergraduate Thesis . University of Arkansas.

Mohammad, M., & Mazahreh, N. (2003). Changes in soil fertility parameters in response to irrigation of forage crops with secondary treated wastewater. Communications in Soil Science and Plant Analysis, 34 , 181–1294.

Mohammad, A. W., Teow, Y. H., Ang, W. L., Chung, Y. T., Oatley-Radcliffe, D. L., & Hila, N. (2015). Nanofiltration membranes review: Recent advances and future prospects. Desalination, 356 , 226–254.

Mohsen, M. S. (2004). Treatment and reuse of industrial effluents: Case study of a thermal power plant. Desalination, 167 , 75–86.

Mostafaii, G., Chimehi, E., Gilasi, H. R., & Iranshahi, L. (2017). Investigation of zinc oxide nanoparticles effects on removal of total coliform bacteria in activated sludge process effluent of municipal wastewater. Journal of Environmental Science and Technology, 1 , 49–55.

Naddeo, V., Belgiorno, V., Ricco, D., & Kassinos, D. (2009). Degradation of diclofenac by sonolysis, ozonation and their simultaneous application. Ultrasonics Sonochemistry, 16 , 790–794.

Nagavallemma, K. P., Wani, S. P., Lacroix, S., Padmaja, V. V., Vineela, C., Babu, R. M., & Sahrawat, K. L. (2006). Vermicomposting: recycling wastes into valuable organic fertilizer. SAT eJournal, 2 , 1–16.

Narain, D. M., Bartholomeus, R. P., Dekker, S. C., & Van Wezel, A. P. (2020). Natural purification through soils: Risks and opportunities of sewage effluent reuse in sub-surface irrigation. In In: Reviews of Environmental Contamination and Toxicology (Continuation of Residue Reviews) (pp. 1–33). Springer. https://doi.org/10.1007/398_2020_49 .

Naylor, N. R., Atun, R., Zhu, N., Kulasabanathan, K., Silva, S., Chatterjee, A., Knight, G. M., & Robotham, J. V. (2018). Estimating the burden of antimicrobial resistance: a systematic literature review. Antimicrobial Resistance and Infection Control, 7 , 58.

Ndegwa, P. M., & Thompson, S. A. (2001). Integrated composting and vermicomposting in the treatment and bioconversion of biosolids. Bioresource Technology, 76 , 107–112.

Nizam, N. U. M., Hanafiah, M. M., Noor, I. M., & Karim, H. I. A. (2020). Efficiency of five selected aquatic plants in phytoremediation of aquaculture wastewater. Applied Sciences, 10 , 2712.

Njuguna, S. M., Makokha, V. A., Yan, X., Gituru, R. W., Wang, Q., & Wang, J. (2019). Health risk assessment by consumption of vegetables irrigated with reclaimed wastewater: A case study in Thika (Kenya). Journal of Environmental Management, 231 , 576–581.

Nmaya, M. M., Agam, M. A., Matias-Peralta, H. M., Yabagi, J. A., & Kimpa, M. I. (2017). Freshwater green microalga for bioremediation of river melaka heavy metals contamination. Journal of Science and Technology, 9 , 118–123.

Nour, A. H., & Zainal, Z. (2014). Membrane fouling control by ultrasonic membrane anaerobic system (UMAS) to produce methane gas. International Journal of Engineering Science Research Technology, 3 , 487–497.

Nourani, V., Elkiran, G., & Abba, S. I. (2018). Wastewater treatment plant performance analysis using artificial intelligence – An ensemble approach. Water Science and Technology, 78 (10), 2064–2076.

Numberger, D., Ganzert, L., Zoccarato, L., Mühldorfer, K., Sauer, S., & Grossart, H. P. (2019). Characterization of bacterial communities in wastewater with enhanced taxonomic resolution by full-length 16S rRNA sequencing. Scientific Reports, 9 , 9673.

Odigie, J. O. (2014). Harmful effects of wastewater disposal into water bodies: A case review of the Ikpoba river, Benin city, Nigeria. Tropical Freshwater Biology, 23 , 87–101.

Oilgae Guide to Algae-based Wastewater Treatment. (2014). Commonly used algae strains for wastewater treatment. http://www.oilgae.com/blog/2014/01/commonly-used-algae-strains-for-waste-water-treatment.html . Accessed 5 May 2021

Okoh, A. I., Sibanda, T., & Gusha, S. S. (2010). Inadequately treated wastewater as a source of human enteric viruses in the environment. International Journal of Environmental Research and Public Health, 7 , 2620–2637.

Oturan, M. A., & Aaron, J. J. (2014). Advanced oxidation processes in water/wastewater treatment: Principles and applications. A review. Critical Reviews in Environmental Science and Technology, 44 , 2577–2641.

Paleologou, A., Marakas, H., Xekoukoulotakis, N. P., Moya, A., Vergara, Y., Kalogerakis, N., Gikas, P., & Mantzavinos, D. (2007). Disinfection of water and wastewater by TiO2 photocatalysis, sonolysis and UV-C irradiation. Catalysis Today, 129 , 136–142.

Pan, B., & Xing, B. S. (2008). Adsorption mechanisms of organic chemicals on carbon nanotubes. Environmental Science and Technology, 42 , 9005–9013.

Panthi, S., Sapkota, A. R., Raspanti, G., Allard, S. M., Bui, A., Craddock, H. A., Murray, R., et al. (2019). Pharmaceuticals, herbicides, and disinfectants in agricultural water sources. Environmental Research, 174 , 1–8.

Park, K. Y., Maeng, S. K., Song, K. G., & Ahn, K. H. (2008). Ozone treatment of wastewater sludge for reduction and stabilization. Journal Environmental Science Health. Part A, Toxic/Hazardous Substances & Environmental Engineering, 43 , 1546–1550.

Pedrero, F., Kalavrouziotis, I., Alarcón, J. J., Koukoulakis, P., & Asano, T. (2010). Use of treated municipal wastewater in irrigated agriculture. Review of some practices in Spain and Greece. Agricultural Water Management, 97 , 1233–1241.

Peng, S. M., Chen, Y. D., Guo, W. Q., Yang, S. S., Wu, Q. L., Luo, H. C., & Ren, N. Q. (2014). The Application of computational fluid dynamics (CFD) in wastewater biological treatment field. Applied Mechanics and Materials, 507 , 711–715.

Pesoutova, R., Hlavinek, P., & Matysikova, J. (2011). Use of advanced oxidation processes for textile wastewater treatment- A review. Food and Environmental Safety, 10 , 59–65.

Petrier, C., Jeunet, A., Luche, J. L., & Reverdy, G. (1992). Unexpected frequency effects on the rate of oxidative processes induced by ultrasound. Journal of the American Chemical Society, 25 , 148–3150.

Pham-Duc, P., Nguyen-Viet, H., Hattendorf, J., et al. (2014). Diarrhoeal diseases among adult population in an agricultural community Hanam province, Vietnam, with high wastewater and excreta reuse. BMC Public Health, 14 , 978.

Phull, S. S., Newman, A. P., Lorimer, J. P., Pollet, T. J., & Mason, T. J. (1997). The development and evaluation of ultrasound in the biocidal treatment of water. Ultrasonics Sonochemistry, 4 , 157–164.

Poustie, A., Yang, Y., Verburg, P., Pagilla, K., & Hanigan, D. (2020). Reclaimed wastewater as a viable water source for agricultural irrigation: A review of food crop growth inhibition and promotion in the context of environmental change. Science of the Total Environment, 739 , 139756.

Punshon, T., Jackson, B. P., Meharg, A. A., Warczack, T., Scheckel, K., & Guerinot, M. L. (2017). Understanding arsenic dynamics in agronomic systems to predict and prevent uptake by crop plants. Science of the Total Environment, 581–582 , 209–220.

Puzas, J. E., Campbell, J., O’Keefe, R. J., & Rosier, R. N. (2004). Lead toxicity in the skeleton and its role in osteoporosis. In Nutrition and Bone Health (pp. 373–376). Humana Press.

Qadir, M., Wichelns, D., Raschid-Sally, L., McCornick, P. G., Drechsel, P., Bahri, A., et al. (2010). The challenges of wastewater irrigation in developing countries. Agricultural Water Management, 97 , 561–568.

Raes, J., Foerstner, K. U., & Bork, P. (2007). Get the most out of your metagenome: Computational analysis of environmental sequence data. Current Opinion in Microbiology, 10 , 490–498.

Ramadas, M., & Samantaray, A. K. (2018). Applications of remote sensing and GIS in water quality monitoring and remediation: A state-of-the-art review. In S. Bhattacharya, A. Gupta, A. Gupta, & A. Pandey (Eds.), Water remediation. Energy, Environment, and Sustainability . Springer.

Rizvi, H., Ahmad, N., Abbas, F., Bukhari, I. H., Yasar, A., Ali, S., Yasmeen, T., & Riaz, M. (2015). Start-up of UASB reactors treating municipal wastewater and effect of temperature/sludge age and hydraulic retention time (HRT) on its performance. Arabian Journal of Chemistry, 8 , 780–786.

Russ, R., Rau, J., & Stolz, A. (2000). The function of cytoplasmic flavin reductases in the reduction of azodyes by bacteria. Applied and Environmental Microbiology, 66 , 1429–1434.

Sacks, M., & Bernstein, N. (2011). Utilization of reclaimed wastewater for irrigation of field-grown melons by surface and subsurface drip irrigation. Israel Journal of Plant Sciences, 59 , 159–169.

Sağ, Y. (2001). Biosorption of heavy metals by fungal biomass and modeling of fungal biosorption: A review. Separation and Purification Reviews, 30 , 1–48.

Salem, H. M., Eweida, E. A., & Farag, A. (2000). Heavy metals in drinking water and their environmental impact on human health (pp. 542–556). ICEHM .

Samarghandi, M. R., Nouri, J., Mesdaghinia, A. R., Mahvi, A. H., Nasseri, S., & Vaezi, F. (2007). Efficiency removal of phenol, lead and cadmium by means of UV/TiO2/H2O2 processes. International journal of Environmental Science and Technology, 4 , 19–25.

Samie, A., Obi, L., Igumbor, O., & Momba, B. (2009). Focus on 14 sewage treatment plants in the Mpumalanga province, South Africa in order to gauge the efficiency of wastewater treatment. African Journal of Microbiology Research, 8 , 3276–3285.

Samstag, R. W., Ducoste, J. J., Griborio, A., Nopens, I., Batstone, D. J., Wicks, J., & Laurent, J. (2016). CFD for wastewater treatment: An overview. Water Science and Technology, 74 , 549–563.

Santajit, S., & Indrawattana, N. (2016). Mechanisms of antimicrobial resistance in ESKAPE pathogens. BioMed Research International, 2016 , 2475067.

Sato, T., Qadir, M., Yamamoto, S., Endo, T., & Zahoor, A. (2013). Global, regional, and country level need for data on wastewater generation, treatment, and use. Agricultural Water Management, 130 , 1–13.

Scherba, G., Weigel, R. M., & Obrien, W. D. (1991). Quantitative assessment of the germicidal efficacy of ultrasonic energy. Applied and Environmental Microbiology, 57 , 2079–2084.

Schloss, P. D., & Handelsman, J. (2005). Metagenomics for studying unculturable microorganisms: Cutting the Gordian knot. Genome Biology, 6 , 229.

Schmeisser, C., Steele, H., & Streit, W. R. (2007). Metagenomics, biotechnology with non-culturable microbes. Applied Microbiology and Biotechnology, 75 , 955–962.

Scott, C. A., Faruqui, N. I., & Raschid-Sally, L. (2004). Wastewater use in irrigated agriculture: Management challenges in developing countries. In C. A. Scott, N. I. Faruqui, & L. Raschid-Sally (Eds.), Wastewater use in irrigated agriculture: Confronting the livelihood and environmental realities (pp. 1–10). CABI Publishing.

Scott, C. A., Drechsel, P., Raschid-Sally, L., Bahri, A., Mara, D., Redwood, M., et al. (2009). Wastewater irrigation and health: Challenges and Outlook for mitigating risks in low-income countries. In P. Drechsel, C. A. Scott, L. Raschid-Sally, M. Redwood, & A. Bahri (Eds.), In: Wastewater irrigation and health: Assessing and mitigating risk in low-income countries (pp. 381–394). Earthscan .

Sengupta, S., Nawaz, T., & Beaudry, J. (2015). Nitrogen and phosphorus recovery from wastewater. Current Pollution Reports, 1 , 155–166.

Shakir, R., Davis, S., Norrving, B., Grisold, W., Carroll, W. M., Feigin, V., & Hachinski, V. (2016). Revising the ICD: Stroke is a brain disease. Lancet, 19 , 2475–2476.

Sharma, N. K., Bhardwaj, S., Srivastava, P. K., Thanki, Y. J., Gadhia, P. K., & Gadhia, M. (2012). Soil chemical changes resulting from irrigating with petrochemical effluents. International journal of Environmental Science and Technology, 9 , 361–370.

Sheet, I., Kabbani, A., & Holail, H. (2014). Removal of heavy metals using nanostructured graphite oxide, silica nanoparticles and silica/ graphite oxide composite. Energy Procedia, 50 , 130–138.

Shen, Y., Oki, T., Kanae, S., Hanasaki, N., Utsumi, N., & Kiguchi, M. (2014). Projection of future world water resources under SRES scenarios: An integrated assessment. Hydrological Sciences Journal, 59 , 1775–1793.

Shuval, H. I., Yekutiel, P., & Fattal, B. (1985). Epidemiological evidence for helminth and cholera transmission by vegetables irrigated with wastewater. Jerusalem - Case study. Water Science and Technology, 17 , 433–442.

Siezen, R. J., & Galardini, M. (2008). Genomics of biological wastewater treatment. Microbial Biotechnology, 1 , 333–340.

Singh, A., Sawant, M., Kamble, S. J., Herlekar, M., Starkl, M., Aymerich, E., et al. (2019). Performance evaluation of a decentralized wastewater treatment system in India. Environmental Science and Pollution, 26 , 21172–21188.

Sinha, R. K., Herat, S., Bharambe, G., & Brahambhatt, A. (2010). Vermistabilization of sewage sludge (biosolids) by earthworms: Converting a potential biohazard destined for land disposal into a pathogen free, nutritive and safe biofertilizer for farms. Waste Management and Research, 28 , 872–881.

Smith, R. G. (1995). Water reclamation and reuse. Water Environment Research, 67 , 488–495.

Soni, R., Pal, A. K., Tripathi, P., Lal, J. A., Kesari, K., & Tripathi, V. (2020). An overview of nanoscale materials on the removal of wastewater contaminants. Applied Water Science, 10 , 189.

Spina, F., Anastasi, A., Prigione, V., Tigini, V., & Varese, G. C. (2012). Biological treatment of industrial wastewaters: A fungal approach. Chemical Engineering Transactions, 27 , 175–180.

Srivastava, A., Srivastava, O. N., Talapatra, S., Vajtai, R., & Ajayan, P. M. (2004). Carbon nanotube filters. Nature Materials, 3 , 610–614.

SWRCB (2011) Order No. R3-2011-0222: waste discharge requirements NPDES general permit for discharges of highly treated groundwater to surface waters, NPDES NO. CAG993002, California State Water Quality Control Board.

Tacconelli, E., Carrara, E., Savoldi, A., Harbarth, S., Mendelson, M., Monnet, D. L., et al. (2018). Discovery, research, and development of new antibiotics: The WHO priority list of antibiotic-resistant bacteria and tuberculosis. The Lancet Infectious Diseases, 18 , 318–327.

Tanji, K. K., & Kielen, N. C. (2002). Agricultural drainage water management in arid and semi-arid areas. In FAO Irrigation and Drainage Paper (p. 61). Food and Agriculture Organization.

Taylor, A. A., Tsuji, J. S., Garry, M. R., McArdle, M. E., Goodfellow Jr., W. L., Adams, W. J., et al. (2020). Critical review of exposure and effects: Implications for setting regulatory health criteria for ingested copper. Environmental Management, 65 , 131–159.

Templeton, M. R., Graham, N., & Voulvoulis, N. (2009). Emerging chemical contaminants in water and wastewater. Philosophical Transactions of the Royal Society A, 367 , 3873–3875.

Toze, S. (1997). Microbial pathogens in wastewater. CSIRO Land and Water Technical report 1/97.

Tringe, S. G., Von-Merling, C., Kobayashi, A., Salamov, A. A., Chen, K., & Chang, H. W. (2005). Comparative metagenomics of microbial communities. Science, 308 , 554–557.

Tripathi, V., Tripathi, P. (2017). Antibiotic resistance genes: An emerging environmental pollutant. K.K. Kesari (ed.), Perspectives in Environmental Toxicology , 183-201.

Tsagarakis, K. P., Tsoumanis, P., Chartzoulakis, K., & Angelakis, A. N. (2001). Water resources status including wastewater treatment and reuse in Greece. Water International, 26 , 252–258.

Tytła, M. (2019). Assessment of heavy metal pollution and potential ecological risk in sewage sludge from municipal wastewater treatment plant located in the most industrialized region in Poland—Case study. International Journal of Environmental Research and Public Health, 16 , 2430.

Ungureanu, N., Vlăduț, V., Dincă, M., Zăbavă, B. Ș. (2018). Reuse of wastewater for irrigation, a sustainable practice in arid and semi-arid regions. In Proceedings of the 7th International Conference on Thermal Equipment, Renewable Energy and Rural Development (TE-RE-RD), Drobeta-Turnu Severin, Romania, 31 May–2 June. pp. 379–384.

Ungureanu, N., Vlăduț, V., & Voicu, G. (2020). Water Scarcity and wastewater reuse in crop irrigation. Sustainability, 12 (21), 9055.

Upadhyay, K., & Srivastava, J. K. (2005). Application of ozone in the treatment of industrial and municipal wastewater. Journal of Industrial Pollution Control, 21 , 235–245.

US EPA. (2004). Guidelines for Water Reuse 625/R-04/108 . Environmental Protection Agency.

US EPA. (2012). Guidelines for Water Reuse 600/R-12/618 . Environmental Protection Agency.

Vélez, E., Campillo, G. E., Morales, G., Hincapié, C., Osorio, J., Arnache, O., et al. (2016). Mercury removal in wastewater by iron oxide nanoparticles. Journal of Physics: Conference Series, 687 , 012050.

Vergili, I. (2013). Application of nanofiltration for the removal of carbamazepine, diclofenac and ibuprofen from drinking water sources. Journal of Environmental Management, 127 , 177–187.

Vogelmann, E. S., Awe, G. O., & Prevedello, J. (2016). Selection of plant species used in wastewater treatment. In Wastewater treatment and reuse for metropolitan regions and small cities in developing countries (pp. 1–10). Publisher.

Volesky, B. (1994). Advances in biosorption of metals: Selection of biomass types. FEMS Microbiology Reviews (Amsterdam), 14 , 291–302.

Von-Sperling, M., & Chernicharo, C. A. L. (2005). Biological Wastewater treatment in warm climate regions (1st ed.p. 810). IWA Publishing.

Wani, A. L., Ara, A., & Usmani, J. A. (2015). Lead toxicity: a review. Interdisciplinary Toxicology, 8 , 55–64.

Webster, G. M. (2010). Chemicals, Health and Pregnancy Study (CHirP). Vancouver, BC: University of British Columbia, Centre for Health and Environment Research (CHER) and School for Occupational and Environmental Hygiene (SOEH). http://www.ncceh.ca/sites/default/files/Health_effects_PFCs_Oct_2010.pdf . Accessed Sept 2019.

Westcot, D. W. (1997). Quality control of wastewater for irrigated crop production. In In Chapter 2 - Health risks associated with wastewater use FAO Water Report (10th ed., p. 86).

WHO (1973) WHO meeting of experts on the reuse of effluents: Methods of wastewater treatment and health safeguards & World Health Organization. Reuse of effluents: Methods of wastewater treatment and health safeguards, report of a WHO meeting of experts [meeting held in Geneva from 30 November to 6 December 1971].

WHO. (1989) Health guidelines for the use of wastewater in agriculture and aquaculture. Technical Report Series No. 74. World Health Organization, Geneva.

WHO (2003).Copper in drinking-water. Background document for preparation of WHO Guidelines for drinking-water quality. Geneva, World Health Organization (WHO/SDE/WSH/03.04/88).

WHO-World Health Organization. (2006). Guidelines for the Safe Use of Wastewater, Excreta and Greywater . In Wastewater Use in Agriculture (2nd ed.). WHO-World Health Organization.

Winpenny, J., Heinz, I., Koo-Oshima, S., Salgot, M., Collado, J., Hernandex, F., et al. (2010). The Wealth of waste: The economics of wastewater use in agriculture. In Food and Agriculture Organization of the United Nations (p. 35). FAO Water Reports .

World Bank. (2010). Improving wastewater use in agriculture: An emerging priority (p. 169). A report of the Water Partnership Program.

World Resources Institute (WRI), (2020) Aqueduct country rankings. Available online: https://www.wri.org/applications/aqueduct/country-rankings/ Accessed 3 Sept 2020.

Xiao, R., Wang, S., Li, R., Wang, J. J., & Zhang, Z. (2017). Ecotoxicology and environmental safety soil heavy metal contamination and health risks associated with artisanal gold mining in Tongguan, Shaanxi, China. Ecotoxicology and Environmental Safety, 141 , 17–24.

Xu, Y. B., Hou, M., Li, Y. F., Huang, L., Ruan, J. J., Zheng, L., et al. (2017). Distribution of tetracycline resistance genes and AmpC β-lactamase genes in representative non-urban sewage plants and correlations with treatment processes and heavy metals. Chemosphere, 170 , 274–281.

Xu, S., Yan, N., Cui, M., & Liu, H. (2020). Decomplexation of Cu(II)/Ni(II)-EDTA by ozone-oxidation process. Environmental Science and Pollution Research, 27 , 812–822.

Yadav, R. K., Goyal, B., Sharma, R. K., Dubey, S. K., & Minhas, P. S. (2002). Post-irrigation impact of domestic sewage effluent on composition of soils, crops and ground water—A case study. Environment International, 28 , 481–486.

Yang, J., Jia, R., Gao, Y., Wang, W., & Cao, P. (2017). The reliability evaluation of reclaimed water reused in power plant project. IOP Conference Series: Earth and Environmental Science, 100 , 012189.

Yaqub, A., Ajab, H., Isa, M. H., Jusoh, H., Junaid, M., & Farooq, R. (2012). Effect of ultrasound and electrode material on electrochemical treatment of industrial wastewater. Journal of New Materials for Electrochemical Systems, 15 , 289–292.

Yuen, H. W., & Becker, W. (2020). Iron toxicity. [Updated 2020 Jun 30]. In: StatPearls [Internet]. StatPearls Publishing; Available from: https://www.ncbi.nlm.nih.gov/books/NBK459224/ .

Zahmatkesh, M., Spanjers, H., Jules, B., & Lier, V. (2018). A novel approach for application of white rot fungi in wastewater treatment under non-sterile conditions: Immobilization of fungi on sorghum. Environmental Technology, 39 (16), 2030–2040.

Zaman, S. B., Hussain, M. A., Nye, R., Mehta, V., Mamun, K. T., & Hossain, N. (2017). A review on antibiotic resistance: Alarm bells are ringing. Cureus, 9 , e1403.

Zamora, S., Marín-Muñíz, J. L., Nakase-Rodríguez, C., Fernández-Lambert, G., & Sandoval, L. (2019). Wastewater treatment by constructed wetland eco-technology: Influence of mineral and plastic materials as filter media and tropical ornamental plants. Water, 11 , 2344.

Zekić, E., Vuković, Z., & Halkijević, I. (2018). Application of nanotechnology in wastewater treatment. GRAĐEVINAR, 70 , 315–323.

Zhang, H., & Reynolds, M. (2019). Cadmium exposure in living organisms: A short review. Science of the Total Environment, 678 , 761–767.

Zhang, Y., & Shen, Y. (2017). Wastewater irrigation: Past, present, and future. Wastewater treatment: Aims and challenges. Water, 6 (3), e1234. https://doi.org/10.1002/wat2.1234 .

Article   Google Scholar  

Zhou, X., & Wang, G. (2010). Nutrient concentration variations during Oenantheja vanica growth and decay in the ecological floating bed system. Journal of Environmental Sciences (China), 22 , 1710–1717.

Zhu, L., Li, Z., & Ketola, T. (2011). Biomass accumulations and nutrient uptake of plants cultivated on artificial floating beds in China’s rural area. Ecological Engineering, 37 , 1460–1466.

Zimmels, Y., Kirzhner, F., & Roitman, S. (2004). Use of naturally growing aquatic plants for wastewater purification. Water Environmental Research, 76 , 220.

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Acknowledgements

All the authors are highly grateful to the authority of the respective departments and institutions for their support in doing this research. The author VT would like to thank Science & Engineering Research Board, New Delhi, India (Grant #ECR/2017/001809). The Author RS is thankful to the University Grants Commission for the National Fellowship (201819-NFO-2018-19-OBC-UTT-78476).

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Department of Applied Physics, Aalto University, Espoo, Finland

Kavindra Kumar Kesari & Janne Ruokolainen

Department of Molecular and Cellular Engineering, Sam Higginbottom University of Agriculture, Technology and Sciences, Naini, Allahabad, India

Ramendra Soni, Jonathan A. Lal & Vijay Tripathi

Department of Health Informatics, College of Public Health and Health Informatics, Qassim University, Al Bukayriyah, Saudi Arabia

Qazi Mohammad Sajid Jamal

Department of Computational Biology and Bioinformatics, Sam Higginbottom University of Agriculture, Technology and Sciences, Naini, Allahabad, India

Pooja Tripathi

Department of Biotechnology, School of Engineering & Technology, Sharda University, Greater Noida, UP, India

Niraj Kumar Jha

Department of Bioengineering, Faculty of Engineering, Integral University, Lucknow, India

Mohammed Haris Siddiqui

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Kesari, K.K., Soni, R., Jamal, Q.M.S. et al. Wastewater Treatment and Reuse: a Review of its Applications and Health Implications. Water Air Soil Pollut 232 , 208 (2021). https://doi.org/10.1007/s11270-021-05154-8

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Water Treatment

How Water Treatment Plants Make Water Safe

Public drinking water systems use different water treatment methods to provide safe drinking water for their communities. Public water systems often use a series of water treatment steps that include coagulation, flocculation, sedimentation, filtration, and disinfection.

Water treatment steps

Coagulation.

Coagulation is often the first step in water treatment. During coagulation, chemicals with a positive charge are added to the water. The positive charge neutralizes the negative charge of dirt and other dissolved particles in the water. When this occurs, the particles bind with the chemicals to form slightly larger particles. Common chemicals used in this step include specific types of salts, aluminum, or iron.

Flocculation

Flocculation follows the coagulation step. Flocculation is the gentle mixing of the water to form larger, heavier particles called flocs. Often, water treatment plants will add additional chemicals during this step to help the flocs form.

Sedimentation

Sedimentation is one of the steps water treatment plants use to separate out solids from the water. During sedimentation, flocs settle to the bottom of the water because they are heavier than water.

Once the flocs have settled to the bottom of the water, the clear water on top is filtered to separate additional solids from the water. During filtration, the clear water passes through filters that have different pore sizes and are made of different materials (such as sand, gravel, and charcoal). These filters remove dissolved particles and germs, such as dust, chemicals, parasites, bacteria, and viruses. Activated carbon filters also remove any bad odors.

Water treatment plants can use a process called ultrafiltration in addition to or instead of traditional filtration. During ultrafiltration, the water goes through a filter membrane with very small pores. This filter only lets through water and other small molecules (such as salts and tiny, charged molecules).

Reverse osmosis external icon is another filtration method that removes additional particles from water. Water treatment plants often use reverse osmosis when treating recycled water external icon (also called reused water) or salt water for drinking.

Disinfection

After the water has been filtered, water treatment plants may add one or more chemical disinfectants (such as chlorine, chloramine, or chlorine dioxide ) to kill any remaining parasites, bacteria, or viruses. To help keep water safe as it travels to homes and businesses, water treatment plants will make sure the water has low levels of the chemical disinfectant when it leaves the treatment plant. This remaining disinfectant kills germs living in the pipes  between the water treatment plant and your tap.

In addition to or instead of adding chlorine, chloramine, or chlorine dioxide, water treatment plants can also disinfect water using ultraviolet (UV) light pdf icon [PDF – 7 pages] external icon or ozone pdf icon [PDF – 7 pages] external icon . UV light and ozone work well to disinfect water in the treatment plant, but these disinfection methods do not continue killing germs as water travels through the pipes between the treatment plant and your tap.

Water treatment plants also commonly adjust water pH and add fluoride after the disinfection step. Adjusting the pH improves taste, reduces corrosion (breakdown) of pipes, and ensures chemical disinfectants continue killing germs as the water travels through pipes. Drinking water with the right amount of fluoride  keeps teeth strong and reduces cavities.

Surface water collects on the ground or in a stream, river, lake, reservoir, or ocean.

Ground water is located below the surface of the earth in spaces between rock and soil.

Water treatment differs by community

Water may be treated differently in different communities depending on the quality of the source water that enters the treatment plant. The water that enters the treatment plant is most often either surface water or ground water . Surface water typically requires more treatment and filtration than ground water because lakes, rivers, and streams contain more sediment (sand, clay, silt, and other soil particles), germs, chemicals, and toxins than ground water.

Some water supplies may contain radionuclides (small radioactive particles), specific chemicals (such as nitrates ), or toxins (such as those made by cyanobacteria ). Specialized methods to control or remove these contaminants can also be part of water treatment. To learn more, visit EPA’s Ground Water and Drinking Water site external icon .

• Water Disinfection with Chlorine and Chloramine
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Environmental Science: Water Research & Technology

A review of modified and hybrid anaerobic baffled reactors for municipal wastewater treatment with a focus on emerging contaminants.

* Corresponding authors

a Department of Civil Engineering, School of Engineering and Technology, University of Technology Sarawak, 868, Brooke Drive, 96000 Sibu, Sarawak, Malaysia

b School of Agriculture and Environmental Science, University of Southern Queensland, West Street, Queensland 4350, Australia E-mail: [email protected]

This review discusses municipal wastewater treatment using anaerobic baffled reactors (ABRs) and modified ABRs. Conventional ABRs can convert organic carbon to renewable energy in the form of biogas. ABRs can achieve more than 90% COD removal at HRT as low as 8 hours at mesophilic temperatures, while COD removal in the range of 70–90% is typical at uncontrolled temperatures. However, effluents from ABRs do not meet discharge criteria and must be polished. Several techniques have been applied to improve the effluent quality including: pre-screening of raw wastewater using a mesh or sedimentation tank, inoculation with acclimatized sludge, effluent recirculation, electrocoagulation, microbial electrodes for improved VFA degradation, COD degradation and methane production, packing materials, carriers or meshes in individual compartments, polymeric membranes in the final compartment or external to the ABR, constructed wetlands and aerobic bioreactors. Recently, much research has focused on concurrent carbon and nitrogen removal in modified ABRs using novel strategies including microaeration, membrane aerated biofilms, an ABR followed by an aerobic membrane bioreactor with sludge recycling, anammox bacteria and nitrite/nitrate-dependent anaerobic methane oxidation bacteria. For P removal, promising chemical techniques include electrocoagulation and biological P removal includes denitrifying phosphate accumulating microorganisms. Some of these techniques applied in independent studies resulted in effluents containing <20 mg L −1 BOD, <1 mg L −1 TN and 0.2 mg L −1 TP, indicating the feasibility of mainstream anaerobic treatment of municipal wastewater, but pilot scale studies on biogas production and C, N and P removal are still lacking. Furthermore, ABRs have also been found to degrade concurrently emerging contaminants in municipal wastewater such as perchlorate, nitrophenols, and antibiotics with no effect on COD removal at typical concentrations found in municipal wastewater, but for some complex organics, an aerobic step is required for the complete oxidation.

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• Review Article
• Published: 20 March 2008

Science and technology for water purification in the coming decades

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One of the most pervasive problems afflicting people throughout the world is inadequate access to clean water and sanitation. Problems with water are expected to grow worse in the coming decades, with water scarcity occurring globally, even in regions currently considered water-rich. Addressing these problems calls out for a tremendous amount of research to be conducted to identify robust new methods of purifying water at lower cost and with less energy, while at the same time minimizing the use of chemicals and impact on the environment. Here we highlight some of the science and technology being developed to improve the disinfection and decontamination of water, as well as efforts to increase water supplies through the safe re-use of wastewater and efficient desalination of sea and brackish water.

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Montgomery, M. A. & Elimelech, M. Water and sanitation in developing countries: including health in the equation. Environ. Sci. Technol. 41 , 17–24 (2007)

Article   ADS   PubMed   Google Scholar  

Lima, A. A. M. et al. Persistent diarrhea signals a critical period of increased diarrhea burdens and nutritional shortfalls: a prospective cohort study among children in northeastern brazil. J. Infect. Dis. 181 , 1643–1651 (2000)

Article   CAS   PubMed   Google Scholar  

Behrman, J. R., Alderman, H. & Hoddinott, J. Hunger and malnutrition. in Copenhagen Consensus—Challenges and Opportunities (London, 2004) OCLC 57489365 (London School of Hygiene and Tropical Medicine, 2004); 〈 http://www.copenhagenconsensus.com/Files/Filer/CC/Papers/ Hunger%5Fand%5FMalnutrition%5F070504.pdf 〉

Google Scholar  

Singh, P. & Bengtson, L. The impact of warmer climate on melt and evaporation for the rainfed, snowfed and glacierfed basins in the Himalayan region. J. Hydrol. 300 , 140–154 (2005)

Article   ADS   Google Scholar  

Shiyin, L., Wenxin, S., Shen, Y. & Li, G. Glacier changes since the Little Ice Age maximum in the western Qilian Shan, northwest China, and consequences of glacier runoff for water supply. J. Glaciol. 49 , 117–124 (2003)

Barnett, T. P., Adam, J. C. & Lettenmaier, D. P. Potential impacts of a warming climate on water availability in snow-dominated regions. Nature 438 , 303–309 (2005)

Article   ADS   CAS   PubMed   Google Scholar  

Bradley, R. S., Vuille, M., Diaz, H. F. & Vergara, W. Threats to water supplies in the tropical Andes. Science 312 , 1755–1756 (2006)

van der Kooij, D. in Heterotrophic Plate Counts and Drinking-water Safety: The Significance of HPCs for Water Quality and Human Health (eds Bartram, J., Cotruvo, J., Exner, M., Fricker, C. & Glasmacher, A.) 199–232 (IWA Publishing, World Health Organization, Geneva, 2003)

Pitman, G. K. Bridging Troubled Waters—Assessing The World Bank Water Resources Strategy (World Bank Publications, Washington DC, 2002)

World Health Organization. Emerging Issues in Water and Infectious Disease 1–22 (World Health Organization, Geneva, 2003)

United States Environmental Protection Agency. 40 CFR parts 9, 141 & 142 National Primary Drinking Water Regulations: Long term 2 enhanced surface water treatment rule; final rule. Federal Register 71 , 653–702 (2006)

United States Environmental Protection Agency. 40 CFR parts 9, 141, & 142 National Primary Drinking Water Regulations: Stage 2 disinfectants and disinfection byproducts rule; final rule. Federal Register 71 , 388–493 (2006)

Krasner, S. W. et al. Occurrence of a new generation of disinfection byproducts. Environ. Sci. Technol. 40 , 7175–7185 (2006)

Muellner, M. G. et al. Haloacetonitriles vs. regulated haloacetic acids: are nitrogen-containing DBPs more toxic? Environ. Sci. Technol. 41 , 645–651 (2007)

Centers for Disease Control and Prevention. Safe Water Systems for the Developing World: A Handbook for Implementing Household-Based Water Treatment and Safe Storage Projects (CDC, Atlanta, 2000)

Simonet, J. & Gantzer, C. Inactivation of poliovirus 1 and f-specific RNA phages and degradation of their genomes by UV irradiation at 254 nanometers. Appl. Environ. Microbiol. 72 , 7671–7677 (2006)

Article   CAS   PubMed   PubMed Central   Google Scholar  

Nuanualsuwan, S. & Cliver, D. O. Capsid functions of inactivated human picornaviruses and feline calicivirus. Appl. Environ. Microbiol. 69 , 350–357 (2003)

Coyne, C. B. & Bergelson, J. M. CAR: A virus receptor within the tight junction. Adv. Drug Deliv. Rev. 57 , 869–882 (2005)

Seiradake, E., Lortat-Jacob, H., Billet, O., Kremer, E. J. & Cusack, S. Structural and mutational analysis of human Ad37 and canine adenovirus 2 fiber heads in complex with the D1 domain of coxsackie and adenovirus receptor. J. Biol. Chem. 281 , 33704–33716 (2006)

Hawkins, C. L., Pattison, D. I. & Davies, M. J. Hypochlorite-induced oxidation of amino acids, peptides and proteins. Amino Acids 25 , 259–274 (2003)

Nightingdale, Z. D. et al. Relative reactivity of lysine and other peptides-bound amino acids to oxidation by hypochlorite. Free Radic. Biol. Med. 29 , 425–433 (2000)

Article   Google Scholar  

Bergt, C., Fu, X., Huq, N. P., Kao, J. & Heinecke, J. W. Lysine residues direct the chlorination of tyrosines in Y XX K motifs of apolipoprotein A-I when hypochlorous acid oxidizes high density lipoprotein. J. Biol. Chem. 279 , 7856–7866 (2004)

Pattison, D. I. & Davies, M. J. Kinetic analysis of the role of histidine chloramines in hypochlorous acid mediated protein oxidation. Biochemistry 44 , 7378–7387 (2005)

Medina-Kauwe, L. K. Endocytosis of adenovirus and adenovirus capsid proteins. Adv. Drug Deliv. Rev. 55 , 1485–1496 (2003)

Yates, M. V., Malley, J., Rochelle, P. & Hoffman, R. Effect of adenovirus resistance on UV disinfection requirements: A report on the state of adenovirus science. J. Am. Water Works Assoc. 98 , 93–106 (2006)

Article   CAS   Google Scholar  

Li, Q., Liang, W. & Shang, J. K. Enhanced visible-light absorption from PdO nanoparticles in nitrogen-doped titanium oxide thin films. Appl. Phys. Lett. 90 , 063109 (2007)

Article   ADS   CAS   Google Scholar  

Fu, P., Luan, Y. & Dai, X. Preparation of activated carbon fibers supported TiO2 photocatalyst and evaluation of its photocatalytic reactivity. J. Mol. Catal. Chem. 221 , 81–88 (2004)

Medina-Valtierra, J., Garcia-Servin, J., Frausto-Reyes, C. & Calixto, S. The photocatalytic application and regeneration of anatase thin films with embedded commercial TiO2 particles deposited on glass microrods. Appl. Surf. Sci. 252 , 3600–3608 (2006)

Changrani, R. G. & Raupp, G. B. Two-dimensional heterogeneous model for a reticulated-foam photocatalytic reactor. Am. Inst. Chem. Eng. J. 46 , 829–842 (2000)

Molinari, R., Palmisano, L., Drioli, E. & Schiavello, M. Studies on various reactor configurations for coupling photocatalysis and membrane processes in water purification. J. Membr. Sci. 206 , 399–415 (2002)

Lin, H. & Valsaraj, K. T. Development of an optical fiber monolith reactor for photocatalytic wastewater treatment. J. Appl. Electrochem. 35 , 699–708 (2005)

Blanco-Galvez, J., Fernandez-Ibanez, P. & Malato-Rodriguez, S. Solar photocatalytic detoxification and disinfection of water: Recent overview. J. Solar Energy Eng. 129 , 4–15 (2007)

Gill, L. W. & McLoughlin, O. A. Solar disinfection kinetic design parameters for continuous flow reactors. J. Solar Energy Eng. 129 , 111–118 (2007)

Schwarzenbach, R. P. et al. The challenge of micropollutants in aquatic systems. Science 313 , 1072–1077 (2006)

Sarkar, S. et al. Well-head arsenic removal units in remote villages of Indian subcontinent: Field results and performance evaluation. Water Res. 39 , 2196–2206 (2005)

Khan, A. H. et al. Appraisal of a simple arsenic removal method for groundwater of Bangladesh. J. Environ. Sci. Health Part A 35 , 1021–1041 (2000)

Silliman, S. E., Boukari, M., Crane, P., Azonsi, F. & Neal, C. R. Observations on elemental concentrations of groundwater in central Benin. J. Hydrol. 335 , 374–388 (2007)

Rasul, S. B. et al. Electrochemical measurement and speciation of inorganic arsenic in groundwater of Bangladesh. Talanta 58 , 33–43 (2002)

Chen, Z. L., Akter, K. F., Rahman, M. M. & Naidu, R. Speciation of arsenic by ion chromatography inductively coupled plasma mass spectrometry using ammonium eluents. J. Sep. Sci. 29 , 2671–2676 (2006)

Sultan, J. & Gabryelski, W. Structural identification of highly polar nontarget contaminants in drinking water by ESI-FAIMS-Q-TOF-MS. Anal. Chem. 78 , 2905–2917 (2006)

Kuo, T.-C. et al. Gateable nanofluidic interconnects for multilayered microfluidic separational systems. Anal. Chem. 75 , 1861–1867 (2003)

Liu, J. W. et al. A catalytic beacon sensor for uranium with parts-per-trillion sensitivity and millionfold selectivity. Proc. Natl Acad. Sci. USA 104 , 2056–2061 (2007)

Article   ADS   CAS   PubMed   PubMed Central   Google Scholar  

Chang, I. H. et al. Miniaturized lead sensor based on lead-specific DNAzyme in a nanocapillary interconnected microfluidic device. Environ. Sci. Technol. 39 , 3756–3761 (2005)

Zhu, P. X. et al. Detection of water-borne E. coli O157 using the integrating waveguide biosensor. Biosens. Bioelectron. 21 , 678–683 (2005)

Snyder, S. A. et al. Role of membranes and activated carbon in the removal of endocrine disruptors and pharmaceuticals. Desalination 202 , 156–181 (2007)

Davis, A. P., Sheppard, D. N. & Smith, B. D. Development of synthetic membrane transporters for anions. Chem. Soc. Rev. 36 , 348–357 (2007)

Snyder, S. A., Vanderford, B. J. & Rexing, D. J. Trace analysis of bromate, chlorate, iodate, and perchlorate in natural and bottled waters. Environ. Sci. Technol. 39 , 4586–4593 (2005)

Garelick, H., Dybowska, A., Valsami-Jones, E. & Priest, N. D. Remediation technologies for arsenic contaminated drinking waters. J. Soils Sediments 5 , 182–190 (2005)

Schideman, L. C., Marinas, B. J., Snoeyink, V. L. & Campos, C. Three-component competitive adsorption model for fixed-bed and moving-bed granular activated carbon adsorbers. Part I. Model development. Environ. Sci. Technol. 40 , 6805–6811 (2006)

Magnuson, M. L. & Speth, T. F. Quantitative structure—Property relationships for enhancing predictions of synthetic organic chemical removal from drinking water by granular activated carbon. Environ. Sci. Technol. 39 , 7706–7711 (2005)

Yavuz, C. T. et al. Low-field magnetic separation of monodisperse Fe3O4 nanocrystals. Science 314 , 964–967 (2006)

Article   PubMed   Google Scholar  

Fournier, D., Hawari, J., Streger, S. H., McClay, K. & Hatzinger, P. B. Biotransformation of N-nitrosodimethylamine by Pseudomonas mendocina KR1. Appl. Environ. Microbiol. 72 , 6693–6698 (2006)

Kraemer, S. M., Xu, J. D., Raymond, K. N. & Sposito, G. Adsorption of Pb(II) and Eu(III) by oxide minerals in the presence of natural and synthetic hydroxamate siderophores. Environ. Sci. Technol. 36 , 1287–1291 (2002)

Chaplin, B. P., Roundy, E., Guy, K. A., Shapley, J. R. & Werth, C. J. Effects of natural water ions and humic acid on catalytic nitrate reduction kinetics using an alumina supported Pd-Cu catalyst. Environ. Sci. Technol. 40 , 3075–3081 (2006)

Daiger, G. T., Rittmann, B. E., Adham, S. & Andreottola, G. Are membrane bioreactors ready for widespread application? Environ. Sci. Technol. 39 , 399A–406A (2005)

Yang, W. B., Cicek, N. & Ilg, J. State-of-the-art of membrane bioreactors: worldwide research and commercial applications in North America. J. Membr. Sci. 270 , 201–211 (2006)

Bixio, D. et al. Wastewater reuse in Europe. Desalination 189 , 89–101 (2006)

Kimura, K., Yamato, N., Yamamura, H. & Watanabe, Y. Membrane fouling in pilot-scale membrane bioreactors (MBRs) treating municipal wastewater. Environ. Sci. Technol. 39 , 6293–6299 (2005)

Ulbricht, M. & Belfort, G. Surface modification of ultrafiltration membranes by low temperature plasma.2. Graft polymerization onto polyacrylonitrile and polysulfone. J. Membr. Sci. 111 , 193–215 (1996)

Carroll, T., Booker, N. A. & Meier-Haack, J. Polyelectrolyte-grafted microfiltration membranes to control fouling by natural organic matter in drinking water. J. Membr. Sci. 203 , 3–13 (2002)

Deratani, A., Li, C. L., Wang, D. M. & Lai, J. Y. New trends in the preparation of polymeric membranes for liquid filtration. Ann. Chim.-Sci. Mater. 32 , 107–118 (2007)

Hester, J. F., Banerjee, P. & Mayes, A. M. Preparation of protein-resistant surfaces on poly(vinylidene fluoride) membranes via surface segregation. Macromolecules 32 , 1643–1650 (1999)

Hester, J. F. & Mayes, A. M. Design and performance of foul-resistant poly(vinylidene fluoride) membranes prepared in a single step by surface segregation. J. Membr. Sci. 202 , 119–135 (2002)

Wang, Y. Q. et al. Remarkable reduction of irreversible fouling and improvement of the permeation properties of poly(ether sulfone) ultrafiltration membranes by blending with pluronic F127. Langmuir 21 , 11856–11862 (2005)

Asatekin, A., Kang, S., Elimelech, M. & Mayes, A. M. Anti-fouling ultrafiltration membranes containing polyacrylonitrile- graft -poly(ethylene oxide) comb copolymer additives. J. Membr. Sci. 298 , 136–146 (2007)

Kang, S., Asatekin, A., Mayes, A. M. & Elimelech, M. Protein antifouling mechanisms of PAN UF membranes incorporating PAN-g-PEO additive. J. Membr. Sci. 298 , 42–50 (2007)

Ulbricht, M. Advanced functional polymer membranes. Polymer 47 , 2217–2262 (2006)

Akthakul, A., Salinaro, R. F. & Mayes, A. M. Antifouling polymer membranes with sub-nanometer size selectivity. Macromolecules 37 , 7663–7668 (2004)

Zhou, M., Kidd, T. J., Noble, R. D. & Gin, D. L. Supported lyotropic liquid crystal polymer membranes: promising materials for molecular-size-selective aqueous nanofiltration. Adv. Mater. 17 , 1850–1853 (2005)

Asatekin, A. et al. Antifouling nanofiltration membranes for membrane bioreactors from self-assembling graft copolymers. J. Membr. Sci. 285 , 81–89 (2006)

Revanur, R., McCloskey, B., Breitenkamp, K., Freeman, B. D. & Emrick, T. Reactive amphiphilic graft copolymer coatings applied to polyvinylidene fluoride ultrafiltration membranes. Macromolecules 40 , 3624–3630 (2007)

Yang, S. Y. et al. Nanoporous membranes with ultrahigh selectivity and flux for the filtration of viruses. Adv. Mater. 18 , 709–712 (2006)

Phillip, W. A., Rzayev, J., Hillmyer, M. A. & Cussler, E. L. Gas and water liquid transport through nanoporous block copolymer membranes. J. Membr. Sci. 286 , 144–152 (2006)

Nunes, S. P., Sforca, M. L. & Peinemann, K.-V. Dense hydrophilic composite membranes for ultrafiltration. J. Membr. Sci. 106 , 49–56 (1995)

Yoon, K. et al. High flux ultrafiltration membranes based on electrospun nanofibrous PAN scaffolds and chitosan coating. Polym. 47 , 2434–2441 (2006)

Lu, Y., Suzuki, T. & Zhang, W. Moore, J. S. &Mariñas, B. J. Nanofiltration membranes based on rigid star amphiphiles. Chem. Mater. 19 , 3194–3204 (2007)

Zhou, Y. & Tol, R. S. J. Evaluating the costs of desalination and water transport. Wat. Resour. Res. 41 , W03003,–1–10 (2005)

Veerapaneni, S., Long, B., Freeman, S. & Bond, R. Reducing energy consumption for seawater desalination. J. Am. Water Works Assoc. 99 , 95–106 (2007)

Morgan, L. A. et al. Solar distillation: a promising alternative for water provision with free energy, simple technology and a clean environment. Desalination 116 , 45–56 (1998)

Bourounia, K., Chaibib, M. T. & Tadrist, L. Water desalination by humidification and dehumidification of air: state of the art. Desalination 137 , 167–176 (2001)

McCutcheon, J. R., McGinnis, R. L. & Elimelech, M. A novel ammonia-carbon dioxide forward (direct) osmosis desalination process. Desalination 174 , 1–11 (2005)

Mathioulakis, E., Belessiotis, V. & Delyannis, E. Desalination by using alternative energy: review and state-of-the-art. Desalination 203 , 346–365 (2007)

Alonitis, S. A., Kouroumbas, K. & Vlachakis, N. Energy consumption and membrane replacement cost for seawater RO desalination plants. Desalination 157 , 151–158 (2003)

Seacord, T. F., Coker, S. D. & MacHarg, J. Affordable desalination collaboration 2005 results. In International Desalination And Water Reuse Quarterly (Green Global Publications, Anaheim, California, 2006)

Spiegler, K. S. & El-Sayed, Y. M. The energetics of desalination processes. Desalination 134 , 109–128 (2001)

Hummer, G., Rasaiah, J. C. & Nowotyta, J. P. Water conduction through the hydrophobic channel of a carbon nanotube. Nature 414 , 188–190 (2001)

Kalra, A., Garde, S. & Hummer, G. Osmotic water transport through carbon nanotube membranes. Proc. Natl Acad. Sci. USA 100 , 10175–10180 (2003)

Hinds, B. J. et al. Aligned multiwalled carbon nanotube membranes. Science 303 , 62–65 (2003)

Article   ADS   PubMed   CAS   Google Scholar  

Holt, J. K. et al. Fast mass transport through sub-2-nanometer carbon nanotubes. Science 312 , 1034–1037 (2006)

Fornasiero, F. et al. Ion exclusion by sub 2-nm carbon nanotube pores. Proc. Natl. Acad. Sci. USA (in the press)

Walz, T., Smith, B. L., Zeidel, M. L., Engel, A. & Agre, P. Biologically-active 2-dimensional crystals of aquaporin chip. J. Biol. Chem. 269 , 1583–1586 (1994)

Qiao, R., Georgiadis, J. G. & Aluru, N. R. Differential ion transport induced electroosmosis and internal recirculation in heterogeneous osmosis membranes. Nano Lett. 6 , 995–999 (2006)

Ishida, H., Donowaki, K., Inoue, Y., Qi, Z. & Sokabe, M. Synthesis and ion channel formation of novel cyclic peptides containing a non-natural amino acid. Chem. Lett. Jpn 26 , 935–954 (1997)

Nednoor, P., Gavalas, V. G., Chopra, N., Hinds, B. J. & Bachas, L. G. Carbon nanotube based biomimetic membranes: mimicking protein channels regulated by phosphorylation. J. Mater. Chem. 17 , 1755–1757 (2007)

Parsegian, A. Energy of an ion crossing a low dielectric membrane: solutions to four relevant electrostatic problems. Nature 221 , 844–846 (1969)

Facciotti, M. T., Rouhani-Manshadi, S. & Glaeser, R. M. Energy transduction in transmembrane ion pumps. Trends Biochem. Sci. 29 , 445–451 (2004)

Martz, E. Protein explorer: easy yet powerful macromolecular visualization. Trends Biochem. Sci. 27 , 107–109 (2002)

van Raaij, M. J., Louis, N., Chroboczek, J. & Cusack, S. Structure of the human adenovirus serotype 2 fiber head domain at 1.5 Å resolution. Virology 262 , 333–343 (1999)

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Acknowledgements

We acknowledge the US National Science Foundation Science and Technology Center, WaterCAMPWS , Center for Advanced Materials for the Purification of Water with Systems.

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Mark A. Shannon, Paul W. Bohn, Menachem Elimelech, John G. Georgiadis, Benito J. Mariñas & Anne M. Mayes

Department of Chemical and Biomolecular Engineering and Department of Chemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA,

Paul W. Bohn

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Shannon, M., Bohn, P., Elimelech, M. et al. Science and technology for water purification in the coming decades. Nature 452 , 301–310 (2008). https://doi.org/10.1038/nature06599

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DOI : https://doi.org/10.1038/nature06599

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• Method 1609.1: Enterococci in Water by TaqMan® Quantitative Polymerase Chain Reaction (qPCR) with Internal Amplification Control (IAC) Assay Quantitative qPCR procedure for the detection of DNA from Enterococci bacteria in ambient water matrices based on the amplification and detection of a specific region of the large subunit ribosomal RNA gene (lsrRNA, 23S rRNA) from these organisms. An IAC is added to each qPCR analysis for Enterococcus DNA and is co-amplified simultaneously with the target sequence to specifically identify polymerase inhibition in the reactions. The advantage of this method over currently accepted culture methods that require 24 − 48 hours to obtain results is its relative rapidity. Results can be obtained by this method in 3-4 hours.  This method gives beach managers the ability to alert beach-goers to unsafe levels of microbial contamination on the same day that the sample is taken.
• Method 1611: Enterococci in Water by TaqMan® Quantitative Polymerase Chain Reaction (qPCR) Assay Quantitative qPCR procedure for the detection of DNA from Enterococci bacteria in ambient water matrices based on the amplification and detection of a specific region of the large subunit ribosomal RNA gene (lsrRNA, 23S rRNA) from these organisms. The advantage of this method over currently accepted culture methods that require 24−48 hours to obtain results is its relative rapidity. Results can be obtained by this method in 3-4 hours. This method gives beach managers the ability to alert beach-goers to unsafe levels of microbial contamination on the same day that the sample is taken.
• Standard of Practice for Determination of Nonylphenol Polyethoxylates (NPnEO, 3 ≤ n ≤ 18) and Octylphenol Polyethoxylates (OPnEO, 2 ≤ n ≤ 12) in Environmental Waters   EXIT Nonylphenol (NP) and octylphenol (OP) have been shown to have toxic effects in aquatic organisms. The prominent source of NP and OP is from common commercial surfactants, which are longer chain alkylphenol ethoxylates (APEOs). This practice screens for the longer chain APEOs which may enter sewage treatment plants at elevated levels and may cause violations of permitted discharge concentration of NP. It covers determination of NP and OP polyethoxylates in water by Single Reaction Monitoring Liquid Chromatography/ Tandem Mass Spectrometry using direct injection liquid chromatography and detected with tandem mass spectrometry detection. 
• Standard Test Method for Bisphenol A in Environmental Waters   EXIT The environmental source of BPA is predominantly from the decomposition of polycarbonate plastics and resins, which are used in a wide range of commercial products. BPA has been reported to have adverse effects in aquatic organisms and may be released into environmental waters directly at trace levels through landfill leachate and POTW effluents. This method has been investigated for use with surface water and secondary and tertiary POTW effluent samples therefore, it is applicable to these matrices only.
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EPA imposes first national limits on 'forever chemicals' in drinking water

For the first time, the Environmental Protection Agency has established national limits for six types of perfluoroalkyl and polyfluoroalkyl substances in drinking water.

The substances, known by the initialism PFAS, are nicknamed "forever chemicals" because they barely degrade and are nearly impossible to destroy , so they can linger permanently in air, water and soil.

As a class of chemicals, PFAS have been associated with a higher risk of certain cancers, heart disease, high cholesterol, thyroid disease , low birth weight and reproductive issues, including decreased fertility. 

Most people in the U.S. have PFAS in their blood , according to the Department of Health and Human Services.

The EPA announced Wednesday that levels of PFOA and PFOS — two types of PFAS commonly used in nonstick or stain-resistant products such as food packaging and firefighting foam — can’t exceed 4 parts per trillion in public drinking water. 

Three additional PFAS chemicals will be restricted to 10 parts per trillion. They are PFNA and PFHxS — older versions of PFAS — and GenX chemicals, a newer generation of chemicals created as a replacement for PFOA.

PFOA and PFOS are the most widely used and studied types of PFAS, according to the EPA. Companies started making them in the 1940s, but the substances were largely phased out of U.S. chemical and product manufacturing in the mid-2000s. However, they persist in the environment and have mostly been replaced by newer types of chemicals within the same class.

The EPA’s new limit reflects the lowest levels of PFOA and PFOS that laboratories can reasonably detect and public water systems can effectively treat. But, according to the agency, water systems should aim to eliminate the chemicals, because there is no safe level of exposure.

Eleven states already have regulatory standards for PFAS in drinking water. The EPA estimated that 6% to 10% of the country’s public water systems — 4,100 to 6,700 systems in total — will need to make changes to meet the new federal limits.

“One hundred million people will be healthier and safer because of this action,” EPA Administrator Michael Regan said Tuesday on a media call, referring to the number of people served by the water systems that will need upgrades.

As of Wednesday, public water systems that don’t monitor for PFAS have three years to start. If they detect PFAS at levels above the EPA limits, they will have two more years to purchase and install new technologies to reduce PFAS in their drinking water.

The EPA estimates that the new limits will prevent thousands of deaths and tens of thousands of serious illnesses.

One of the biggest health concerns associated with PFOA is an increased risk of kidney cancer . Exposure to high levels of PFOS has also been associated with an increased risk of liver cancer .

GenX chemicals have been shown in animal studies to damage the liver, kidneys and immune system, as well as liver and pancreatic tumors. According to studies in rodents, PFNA exposure could lead to developmental issues and PFHxS may disrupt the thyroid system. 

The EPA also set a limit Wednesday for mixtures of at least two of the following chemicals: PFNA, PFHxS, PFBS and GenX. Public water systems can use an equation provided by the EPA to determine whether the cumulative concentrations of the chemicals exceed the agency’s threshold. 

The EPA proposed limits to PFAS in drinking water last year. After it reviewed public comments, it made the limits official Wednesday.

“This is a huge, historic public health win,” said Scott Faber, senior vice president of government affairs for the Environmental Working Group, an activist group that advocates for stricter regulations of drinking water pollutants.

Faber called the new EPA limits “the most important step we’ve taken to improve the safety of our tap water in a generation” and “the single most important step we’ve taken to address PFAS ever.”

Jamie DeWitt, director of the Environmental Health Sciences Center at Oregon State University, said that although the new limits don’t end the problem of PFAS in drinking water, they represent significant progress.

“This is going to give people in contaminated communities at least a sense that the federal government cares about them and cares about their exposure, because I think many people living in PFAS-impacted communities have not felt heard,” she said. 

The EPA said Wednesday that $1 billion in funding is newly available to help states and territories implement PFAS testing and treatment at public water systems and to help owners of private wells do the same. The funding comes from the federal infrastructure law passed in 2021, which set aside $9 billion to address PFAS and other contaminants in water. The money will be distributed as grants.  

Some public water systems have also sued companies that manufacture or previously manufactured PFAS, aiming to hold them accountable for the costs of testing and filtering for PFAS. One such lawsuit resulted in a $1.18 billion settlement last year for 300 drinking water providers nationwide. Another lawsuit awarded $10.5 billion to $12.5 billion , depending on the level of contamination found, to public water systems across the country through 2036.

The most common way to remove PFAS from water is through an activated carbon filter, which traps the chemicals as water passes through. Other options include reverse osmosis or ion exchange resins, which act like tiny magnets that attract PFAS chemicals. 

But even once water is treated for PFAS, it can take a while to see positive impacts, said Anna Reade, director of PFAS advocacy at the National Resources Defense Council, a nonprofit environmental advocacy group. 

“For most of these six chemicals, it’s between two to eight years for the amount in our bodies to decrease by half. So we’re looking at years before we see some substantial decreases in our exposure over time,” she said.

The EPA’s new drinking water limits apply to only a small fraction of the more than 12,000 types of PFAS , so activists are still concerned about overall exposure.

“This is not the final step,” Reade said. “We still have a lot of other PFAS to worry about.”

Aria Bendix is the breaking health reporter for NBC News Digital.

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Desalination system could produce freshwater that is cheaper than tap water

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Engineers at MIT and in China are aiming to turn seawater into drinking water with a completely passive device that is inspired by the ocean, and powered by the sun.

In a paper appearing today in the journal Joule, the team outlines the design for a new solar desalination system that takes in saltwater and heats it with natural sunlight.

The configuration of the device allows water to circulate in swirling eddies, in a manner similar to the much larger “thermohaline” circulation of the ocean. This circulation, combined with the sun’s heat, drives water to evaporate, leaving salt behind. The resulting water vapor can then be condensed and collected as pure, drinkable water. In the meantime, the leftover salt continues to circulate through and out of the device, rather than accumulating and clogging the system.

The new system has a higher water-production rate and a higher salt-rejection rate than all other passive solar desalination concepts currently being tested.

The researchers estimate that if the system is scaled up to the size of a small suitcase, it could produce about 4 to 6 liters of drinking water per hour and last several years before requiring replacement parts. At this scale and performance, the system could produce drinking water at a rate and price that is cheaper than tap water.

“For the first time, it is possible for water, produced by sunlight, to be even cheaper than tap water,” says Lenan Zhang, a research scientist in MIT’s Device Research Laboratory.

The team envisions a scaled-up device could passively produce enough drinking water to meet the daily requirements of a small family. The system could also supply off-grid, coastal communities where seawater is easily accessible.

Zhang’s study co-authors include MIT graduate student Yang Zhong and Evelyn Wang, the Ford Professor of Engineering, along with Jintong Gao, Jinfang You, Zhanyu Ye, Ruzhu Wang, and Zhenyuan Xu of Shanghai Jiao Tong University in China.

A powerful convection

The team’s new system improves on their previous design — a similar concept of multiple layers, called stages. Each stage contained an evaporator and a condenser that used heat from the sun to passively separate salt from incoming water. That design, which the team tested on the roof of an MIT building, efficiently converted the sun’s energy to evaporate water, which was then condensed into drinkable water. But the salt that was left over quickly accumulated as crystals that clogged the system after a few days. In a real-world setting, a user would have to place stages on a frequent basis, which would significantly increase the system’s overall cost.

In a follow-up effort, they devised a solution with a similar layered configuration, this time with an added feature that helped to circulate the incoming water as well as any leftover salt. While this design prevented salt from settling and accumulating on the device, it desalinated water at a relatively low rate.

In the latest iteration, the team believes it has landed on a design that achieves both a high water-production rate, and high salt rejection, meaning that the system can quickly and reliably produce drinking water for an extended period. The key to their new design is a combination of their two previous concepts: a multistage system of evaporators and condensers, that is also configured to boost the circulation of water — and salt — within each stage.

“We introduce now an even more powerful convection, that is similar to what we typically see in the ocean, at kilometer-long scales,” Xu says.

The small circulations generated in the team’s new system is similar to the “thermohaline” convection in the ocean — a phenomenon that drives the movement of water around the world, based on differences in sea temperature (“thermo”) and salinity (“haline”).

“When seawater is exposed to air, sunlight drives water to evaporate. Once water leaves the surface, salt remains. And the higher the salt concentration, the denser the liquid, and this heavier water wants to flow downward,” Zhang explains. “By mimicking this kilometer-wide phenomena in small box, we can take advantage of this feature to reject salt.”

Tapping out

The heart of the team’s new design is a single stage that resembles a thin box, topped with a dark material that efficiently absorbs the heat of the sun. Inside, the box is separated into a top and bottom section. Water can flow through the top half, where the ceiling is lined with an evaporator layer that uses the sun’s heat to warm up and evaporate any water in direct contact. The water vapor is then funneled to the bottom half of the box, where a condensing layer air-cools the vapor into salt-free, drinkable liquid. The researchers set the entire box at a tilt within a larger, empty vessel, then attached a tube from the top half of the box down through the bottom of the vessel, and floated the vessel in saltwater.

In this configuration, water can naturally push up through the tube and into the box, where the tilt of the box, combined with the thermal energy from the sun, induces the water to swirl as it flows through. The small eddies help to bring water in contact with the upper evaporating layer while keeping salt circulating, rather than settling and clogging.

The team built several prototypes, with one, three, and 10 stages, and tested their performance in water of varying salinity, including natural seawater and water that was seven times saltier.

From these tests, the researchers calculated that if each stage were scaled up to a square meter, it would produce up to 5 liters of drinking water per hour, and that the system could desalinate water without accumulating salt for several years. Given this extended lifetime, and the fact that the system is entirely passive, requiring no electricity to run, the team estimates that the overall cost of running the system would be cheaper than what it costs to produce tap water in the United States.

“We show that this device is capable of achieving a long lifetime,” Zhong says. “That means that, for the first time, it is possible for drinking water produced by sunlight to be cheaper than tap water. This opens up the possibility for solar desalination to address real-world problems.”

“This is a very innovative approach that effectively mitigates key challenges in the field of desalination,” says Guihua Yu, who develops sustainable water and energy storage systems at the University of Texas at Austin, and was not involved in the research. “The design is particularly beneficial for regions struggling with high-salinity water. Its modular design makes it highly suitable for household water production, allowing for scalability and adaptability to meet individual needs.”

Funding for the research at Shanghai Jiao Tong University was supported by the Natural Science Foundation of China.

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A number of MIT spinouts and research projects – including the MOXIE instrument that successfully generated oxygen on Mars, a new solar-powered desalination system and MIT spinout SurgiBox – were featured on TIME’s Best Inventions of 2023 list.

Insider reporter Katie Hawkinson explores how MIT researchers developed a new solar-powered desalination system that can remove the salt from seawater for less than the cost of U.S. tap water. Creating a device that relies on solar power, “eliminates a major financial barrier, especially for low-income countries experiencing water scarcity,” Hawkinson explains.

The Hill reporter Sharon Udasin writes that MIT researchers have developed a new solar-powered desalination device that “could last several years and generate water at a rate and price that is less expensive than tap water.” The researchers estimated that “if their model was scaled up to the size of a small suitcase, it could produce about 4 to 6 liters of drinking water per hour,” writes Udasin.

The Daily Beast

MIT researchers have developed a new desalination system that uses solar energy to convert seawater into drinkable water, reports Tony Ho Tran for the Daily Beast . The device could make it possible to, “make freshwater that’s even more affordable than the water coming from Americans’ kitchen faucets.”

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‘Alarming’ bacteria levels found in Seine River, where Olympians will swim

A nonprofit focused on waterway conservation has voiced concern about contamination in Paris’s Seine River ahead of open-water swimming events to be held there at the Olympic and Paralympic Games starting in July.

The Surfrider Foundation said Monday that testing at a bridge, the Pont Alexandre III, between September and March regularly turned up higher, and sometimes much higher, levels of E. coli and enterococci bacteria than the recommended threshold, which can be an indication of fecal matter.

The bridge is the planned finish line for the 10-kilometer marathon swim and the aquatic portion of the Olympic and Paralympic triathlons .

But Ile-de-France precinct officials dismissed the Surfrider tests on Monday, saying the water would be swimmable for the Summer Games after key elements of a $1.5 billion plan to clean up the river are rolled out in April and May. And the city’s deputy mayor for sports and the Olympics and Paralympics, Pierre Rabadan, said in an interview Tuesday in Paris that the findings ignore a steady improvement in water quality over recent years. “I did not learn anything from the surveys they provided,” he said.

The Seine, which winds through Paris, is not historically seen as an appealing place to swim . Entering the water has been banned for a century because of health concerns, including sewage.

But cleaning it up was a marquee commitment made by Parisian authorities as part of their bid to host the 2024 Olympics.

Along with select sporting events, the river is to be the centerpiece of the Opening Ceremonies. Athletes will sail down the Seine on cruise boats with spectators lining its banks , in lieu of the traditional parade on land.

In an open letter, Surfrider said it had growing concerns about the risks to Olympic athletes if the water is still contaminated by July, calling its test results “alarming.”

The cleanup plan has faced other setbacks. In August, the Open Water Swimming World Cup, to be held in the Seine in Paris, was canceled because of low water quality after above-average rainfall. Two of four days of Olympic test events were canceled that month for the same reason.

But in a news release Monday, the Ile-de-France precinct said key structural works in its cleanup plan were yet to be put into place, including the massive new Austerlitz storm water storage basin.

It added that water treatment plant disinfection units that would be activated for the Games were not operating over the Surfrider testing period; that water quality had been degraded by heavy winter rains, which would not be a factor during the Summer Games; and that boats in the Seine, some of which release wastewater into the river, would either be connected to the city’s sanitation network by summer or displaced for the Olympics.

It said the Seine’s water will be “swimmable” in time for the summer events.

“It’s well known that the [winter] period, which is a time with a lot of rain, is not suited for swimming,” Rabadan said.

He said the city’s own measurements show that the water quality was better over the past months than in previous winters, suggesting that cleanup efforts are working. “There is really a continuous improvement in the quality of the Seine,” he said.

Rabadan added that there is no alternative venue for the Olympic and Paralympic swimming events that are expected to be held in the Seine, but that organizers may postpone some competitions by several days if the water quality is insufficient.

Plans to clean up the river have been underway since 2016, and authorities aim to open more than 20 swimmable sites to the public after the Olympics, which Rabadan said will “reconnect residents and tourists a bit more with their urban river” and “provide refreshment opportunities during the summer periods, which keep getting hotter.”

Rick Noack in Paris contributed to this report.