Direct Potable Reuse Research Articles

Water reuse options for decentralised MBR effluents: a case study in South Africa

ABSTRACT Treated wastewater is emerging as a promising alternative water solution. This study evaluated the feasibility of reusing effluents from three decentralised membrane bioreactor (MBR) wastewater treatment facilities in Western Cape, South Africa. Using water quality results from each facility, the technical feasibility of irrigation and both indirect potable and direct potable reuse (DPR) options for MBR effluents was evaluated. Effluents from all facilities typically meet national irrigation standards, with only one site requiring pH correction. Partially recharged groundwater with 25% of its water demand using MBR effluents requires additional treatment for organic matter, faecal coliform, nitrates, colour, saturation index, iron, and manganese parameters to meet drinking water quality upon abstraction. For DPR, MBR effluent must undergo pre-treatment to remove excess organic matter, turbidity, and suspended solids before advanced treatment with reverse osmosis. However, only one facility has economic feasibility for potable reuse with payback periods of 7 and 8 years for DPR and indirect potable reuse, respectively. Potable reuse may not be economical for small-scale MBR plants unless the necessity for drinking water reuse outweighs the financial implications. The study highlights the need for evaluating alternative low-cost technologies for MBR effluent treatment and integrated managed aquifer recharge modelling to assess various groundwater recharge scenarios.

Water Reuse—Retrospective Study on Sustainable Future Prospects

In recent decades, societies and economies across the globe have started to show signs of stress associated with water shortages. Meeting the sustainability benchmarks in arid and semi-arid regions has caused water reuse to be considered a viable alternate source to augment the existing water supply resources. Water reuse, resource recovery, and recycling are extensions of the concept of a circular economy that has been practiced in other fields. Globally, the U.S. has played a leadership role in the development of guidance and regulations for various water reuse applications. Other countries and organizations have also developed similar programs. This paper aims to propose a review of the existing literature and provide a broader perspective of water reuse focusing on the most pressing issues such as direct potable reuse with the backdrop of viral pathogens and perfluorinated compounds. The global history of statutory developments to regulate the selected contaminants has also been discussed by covering the recent advancement in water reuse applications. Technological developments and regulatory trends are chronicled in the context of emerging contaminants linked with an imminent social, industrial, and agricultural prospectus. The proposed high viral log removal credit for water reuse is a challenging task especially at regular intervals; therefore, the treatment requirements must be verified to ensure public safety. The extreme persistence of PFAS, their tendency for buildup in biotic systems, and their removal is another challenging task which requires development of cost effective and efficient technologies. Disparity in the financial and technological capabilities of regional or internal stakeholders of shared watershed or aquifer is a bottleneck in tangible advancements in this area. The role of public–private partnerships in addressing the impending water sustainability challenges is discussed as a model for future direction in funding, managing, and public acceptance.

Authors' reply to correspondence on "direct potable reuse and birth defects prevalence in Texas": An augmented synthetic control method analysis of data from a population-based birth defects registry.

Authors' reply to correspondence on "direct potable reuse and birth defects prevalence in Texas": An augmented synthetic control method analysis of data from a population-based birth defects registry.

Correspondence on “Direct potable reuse and birth defects prevalence in Texas”: An augmented synthetic control method analysis of data from a population-based birth defects registry

Correspondence on “Direct potable reuse and birth defects prevalence in Texas”: An augmented synthetic control method analysis of data from a population-based birth defects registry

A pilot‐scale study of potable reuse impacts on surface water treatment

Abstract Interest is growing in direct potable reuse where advanced‐treated water and raw water are blended and fed directly to a water treatment plant (WTP). However, the impacts of raw water augmentation on treatability at drinking water treatment plants have not been studied extensively. A pilot‐scale treatment system, consisting of coagulation, flocculation, sedimentation, and filtration, was set up at a WTP to treat potential future blends of advanced‐treated water and current raw water. The pilot plant was run with blends from 20% to 100% advanced‐treated water at a range of filtration rates (2–9 gpm/sf) and coagulant doses. Under all conditions, filterable water was produced, achieving acceptable turbidity removal. Turbidity removal by sedimentation was variable (30%–90%). Filtration performance was more consistent, exceeding 90% turbidity reduction under all conditions and achieving lower headloss accumulation rates at higher advanced‐treated water share. These results are optimistic for potable reuse schemes featuring raw water augmentation.

Environmental and socioeconomic aspects related to the acceptance of direct potable reuse in a metropolitan city in Brazil

Environmental and socioeconomic aspects related to the acceptance of direct potable reuse in a metropolitan city in Brazil

Assessing relative risks of municipal wastewater disposal options for Southeast Florida.

A comparative assessment of the risks of the three current wastewater effluent disposal options and three other potential options was conducted for Southeast Florida communities. The question was how the risk to humans from the use of potable reuse compares to the other five available wastewater disposal alternatives. The need for this type of risk assessment is due to the potential to use potable reuse as a water supply and the potential resistance from the public as a result of such a proposal. Water quality data relevant to disposal of wastewater treatment plant effluent from South Florida utilities along with water quality data on the receiving waters and drinking water standards were obtained for the project. The comparison of the public health risks associated with these disposal alternatives indicated that health risks associated with deep wells and direct potable reuse were generally lower than those of the other alternatives.

Multiple barriers as an efficient treatment for removing pesticides aiming direct potable reuse: A pilot scale study

Multiple barriers as an efficient treatment for removing pesticides aiming direct potable reuse: A pilot scale study

Direct potable reuse and birth defects prevalence in Texas: An augmented synthetic control method analysis of data from a population-based birth defects registry.

Direct potable reuse (DPR) involves adding purified wastewater that has not passed through an environmental buffer into a water distribution system. DPR may help address water shortages and is approved or is under consideration as a source of drinking water for several water-stressed population centers in the United States, however, there are no studies of health outcomes in populations who receive DPR drinking water. Our objective was to determine whether the introduction of DPR for certain public water systems in Texas was associated with changes in birth defect prevalence. We obtained data on maternal characteristics for all live births and birth defects cases regardless of pregnancy outcome in Texas from 2003 to 2017 from the Texas Birth Defects Registry and birth and fetal death records. The ridge augmented synthetic control method was used to model changes in birth defect prevalence (per 10,000 live births) following the adoption of DPR by four Texas counties in mid-2013, with county-level data on maternal age, percent women without a high school diploma, percent who identified as Hispanic/Latina or non-Hispanic/Latina Black, and rural-urban continuum code as covariates. There were nonstatistically significant increases in prevalence of all birth defects collectively (average treatment effect in the treated = 53.6) and congenital heart disease (average treatment effect in the treated = 287.3) since June 2013. The estimated prevalence of neural tube defects was unchanged. We estimated nonstatistically significant increases in birth defect prevalence following the implementation of DPR in four West Texas counties. Further research is warranted to inform water policy decisions.

Using Predictive Bayesian Methods to Develop A Comparative Assessment Municipal Wastewater Disposal Methods in Southeast Florida

Predictive Bayesian methods were used to develop a comparative assessment of the risks of six effluent disposal alternatives currently or potentially available to wastewater utilities in Southeast Florida. The alternatives are: 1) deep well injection 2) ocean outfalls following secondary treatment, 3) surface water (canal) discharges following secondary wastewater treatment, filtration and nutrient removal, 4) reclaimed water (secondary treatment plus filtration and high-level disinfection, 5) indirect potable reuse (full treatment with reverse osmosis, plus ultraviolet light and advanced oxidation) and 6) direct potable reuse using reverse osmosis, ultraviolet light and advanced oxidation. Water quality data was gathered from a series of south Florid utilities, south Florida test facilities, receiving waters and other relevant locations to south Florida wastewater effluent disposal. This paper presents the conclusions regarding relative health concerns associated with these disposal alternatives. The results indicated that health risks associated with deep wells and direct potable reuse were generally lower than those of the other alternatives.

Process benefits of ozone/BAC as pretreatment to membrane-based advanced treatment for direct potable reuse

ABSTRACT The state of California, USA, has developed regulations for projects that want to pursue direct potable reuse. One of the most significant requirements is that the treatment train must include ozone and biological activated carbon (ozone/BAC) as pretreatment to a membrane-based treatment train. Ozone/BAC mitigates chemical peaks and diversifies the removal mechanisms of low molecular weight compounds likely to persist in advanced treated water. This paper will present the process benefits of ozone/BAC as pretreatment to the membrane-based treatment train based on testing at a 3,785 m3/d demonstration facility in San Diego, California, USA. One of the most significant benefits of ozone/BAC pretreatment is the improved water quality that benefits not only the product water produced for potable consumption but also the residual stream that is generated with the implementation of the RO process, commonly known as RO concentrate. This improved water quality originates from TOC reduction which is achieved through a combination of chemical oxidation with ozonation and biological growth in the BAC process that results in reduced operating pressures and chemical use for the membrane systems. These process benefits were quantified to develop an overall water cost comparison between a DPR and an indirect potable reuse train.

Life cycle assessment of wastewater reuse alternatives in urban water system

Life cycle assessment of wastewater reuse alternatives in urban water system

Public acceptance in direct potable water reuse: a call for incorporating responsible research and innovation

ABSTRACT As global issues such as climate change and diminishing resources become increasingly pressing, water recycling has moved into the focus. However, the successful implementation of Direct Potable Water Reuse (DPR) projects hinges on securing public acceptance, which remains challenging. This paper aims to flesh out possible reasons for the lingering public rejection of DPR. We will do so by conducting a literature review on how public acceptance is understood and what approaches are proposed to enhance it. These approaches are analyzed using Responsible Research and Innovation principles and the `opening up', `closing down' and `leaving ajar' approaches. Our research identifies an overreliance on the controversial information deficit model, closing down large parts of public engagement. We advocate for becoming more inclusive through the `leaving ajar' approach. Particularly, attention should be paid to reflexivity and responsiveness to public concerns to ensure meaningful public engagement.

Micropoluentes no reúso potável de água: revisão dos documentos orientadores e plantas em operação ao redor do mundo

ABSTRACT The presence of micropollutants in effluents leads to an increased concern regarding the application of recycled water for direct and indirect potable reuse (DPR and IPR, respectively). The study presents a review (last 5 years) of guiding documents and operating plants of potable reuse (PR) globally, focusing on micropollutants. The guiding documents were found through an integrative literature review, while the operating plants were found in a systematic review. The study contemplated 19 regulatory documents, of which 7 address DPR and IPR jointly, 10 only IPR, and 2 only DPR. Standards for micropollutants are defined only in documents regulating IPR. Regarding plants in operation, 38 units were presented, of which 6 are DPR and 32 IPR. Some compounds presented more concern: 1,4-dioxane, 17-β-estradiol, gemfibrozil, perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), sucralose, and triclosan. It is of concern to note the absence of specific standards for micropollutants in DPR regulations. This gap highlights the importance of establishing rigorous guidelines that consider the effects of micropollutants; the study provides a state-of-the-art overview that can guide the advancement of regional regulatory frameworks for the institutionalization of PR worldwide.

Embodied energy and greenhouse gas emissions from wastewater reuse strategies in Indian Himalayan region

Embodied energy and greenhouse gas emissions from wastewater reuse strategies in Indian Himalayan region

Modeling and experimental evaluation of membrane distillation aimed at urine treatment for direct potable reuse in space stations

Improving wastewater reuse systems represents a game changer for the economy of space exploration activities. The goal of this research is to evaluate direct contact membrane distillation for the treatment of urine aimed at direct potable reuse in space stations. A transient, 2-D model able to predict the membrane distillation system behavior under different operating conditions is developed. The model is validated by experimental tests conducted with a synthetic urine-like feed solution, considering both productivity and final water quality. The water flux and quality analyses imply high rejection of soluble salts and organics. However, direct water reuse may be compromised by the ammonia passage. A sensitivity analysis is thus performed to investigate the effects of feed pH, temperature, and cross-flow velocity on water flux and ammonia passage. The system shows the capability of treating 8 L of urine up to 90–95 % recovery rate, during 10 h of daily operation at 40 °C feed and 20 °C distillate inlet temperatures. This amount is sufficient to satisfy four crew members while meeting high system compactness. Concurrently, the ammonia passage may be limited by lowering the feed pH, thus easing the post-treatment steps necessary for safe direct reuse.

Establishing pathogen log reduction value targets for direct potable reuse in the United States

Abstract Communities are now turning to potable reuse to augment their water supply portfolios in response to increasing demand and climate uncertainty. One barrier to broader implementation is a lack of regulations for direct potable reuse (DPR) in some locations. An incomplete understanding of the foundation of existing DPR frameworks may be contributing to this barrier. The objective of this study was to use a publicly available quantitative microbial risk assessment (QMRA) tool—DPRisk—to explain the basis behind California's existing indirect potable reuse regulations, California's draft DPR regulations, and an Expert Panel's response to those draft regulations. Then, leveraging a robust raw wastewater pathogen dataset from the literature, DPRisk was used to justify two alternatives: one based on maximum simulated pathogen concentrations and the other based on 97.4th percentile concentrations. The latter represents an effort to seek equivalency between “raw wastewater” (i.e., California) and “treated effluent” (i.e., Texas) approaches. Using justified QMRA assumptions, the baseline log reduction value (LRV) targets were determined to be 15/11/11 (maximum) or 13/10/10 (97.4th percentile) for viruses, Giardia, and Cryptosporidium. Additionally, instead of augmenting the baseline LRVs to account for undetected treatment process failures, tolerances for off‐specification conditions (e.g., up to 3 logs for 3–12 days per year) were characterized. With this foundational knowledge, stakeholders can better understand and adopt these frameworks or use DPRisk to establish a new framework that better addresses their unique constraints, including considerations for preferred treatment paradigms and capital and operational costs.

Erratum—Evaluating the sustainability of indirect potable reuse and direct potable reuse: A southern Nevada case study

Erratum—Evaluating the sustainability of indirect potable reuse and direct potable reuse: A southern Nevada case study

A Critical Review of Water Reuse: Lessons from Prehistoric Greece for Present and Future Challenges

Wastewater treatment and reuse has passed through different development stages with time. This study reviews the most essential changes in water reclamation and reuses over millennia, focusing on initial approaches in the Hellenic world and discussing the current situation. Based on archeological evidence and time records, the awareness of the Greeks regarding land disposal, irrigation, and water reuse is highlighted. The latter has evolved into a plethora of applications, with Direct Potable Reuse (DPR) representing one of the last modern frontiers. Currently, advances in wastewater treatment and the spreading of wastewater treatment plants producing large amounts of treated effluents increase the potential for water reuse. This is regarded as a critical option for the continuing protection of water resources and human health, while concurrently satisfying water demand, particularly in areas subject to increased water scarcity. The main constraints in the expansion of water reuse practices are discussed, focusing on wastewater treatment efficiency and quality effluent standards issues, as well as on the lack of motivations related to the acceptability of this practice by final users. Against these challenges, the need for a transition from an “issue-by-issue” approach to a broader integrated water management framework is highlighted.

Inorganic and Organic Silicon Fouling of Nanofiltration Membranes during Pilot-Scale Direct Potable Reuse

Inorganic and Organic Silicon Fouling of Nanofiltration Membranes during Pilot-Scale Direct Potable Reuse