Water Reuse Practices Research Articles

Multi-scale assessment of rainwater harvesting availability across the continental U.S.

Addressing resilience, sustainability, and water resource conservation has become increasingly important in the modern world. Challenges arise due to periodic droughts, climate change, and seasonal variability in areas with limited freshwater availability. Therefore, implementing and promoting water reuse is essential. Rainwater harvesting (RWH) is one such alternative, offering benefits in conserving water resources and mitigating droughts while reducing urban flooding and costs by generating alternative lower-cost water sources. Providing users with knowledge of available volumes for harvesting, including homeowners and governmental entities, is key to encouraging this practice. Hydrological data and geographic information systems are fundamental for managing, designing, and projecting rainwater harvesting practices. However, no tools currently integrate this information at multiple scales with current and future climate scenarios. This research aimed to develop a multi-scale assessment tool named H2O HARVEST, for evaluating the availability and potential of rainwater harvesting. Additional benefits of the H2O HARVEST app include aiding decision-making by national governmental entities and analyzing potential future scenarios for homeowner users. The app also provides regulatory policy information at the state level. We offer an app with the necessary capabilities to bridge the technology gap and promote rainwater harvesting practices. Our research demonstrated that RWH has the potential to be a sustainable water reuse practice. For more than 50% of the states, the RWH could supply at least 50% of the water demand. The regions of the US with the greatest potential are the Central and East.

Persulfate photolysis and limited irrigation of recycled wastewater for turfgrass growth: Accumulation of pharmaceutical and personal care products and physiological responses

Recycled wastewater effluent irrigation and implementing limited irrigation rates are two promising strategies for water conservation in agriculture. However, one major challenge is the accumulation and translocation of Pharmaceutical and Personal Care Products (PPCPs) from recycled water to crops. This study investigated the effects of UV persulfate (UV/PS) treatment of recycled water and limited irrigation rate on PPCPs accumulation and physiological responses of St. Augustine turfgrass via a 14-week field trial. Carbamazepine (CBZ), sulfamethoxazole (SMX), triclosan (TCS), fluoxetine (FLX) and diclofenac (DCF) were spiked at 0.1–1.5 µg/L into recycled water and two limited irrigation rates corresponding to 60 % and 80 % of reference Evapotranspiration (ETo) were applied. Results showed that UV/PS removed 60 % of CBZ and > 99 % of other PPCPs from recycled water. Irrigation with UV/PS treated recycled water resulted in approximately a 60 % reduction in CBZ accumulation and complete removal of SMX, DCF, FLX and TCS in both turfgrass leaves and roots. A more limited irrigation rate at 60 % ETo resulted in a higher accumulation of CBZ accumulation compared to 80 % ETo. Similarly, the canopy temperature increased under 60 % ETo irrigation rate compared to 80 % ETo, suggesting that turfgrass under 60 % ETo was more prone to water stress. Applying a 60 % ETo irrigation rate was not sufficient to maintain the turfgrass quality in the acceptable range. A negative correlation between the visual quality and cumulative mass of PPCPs in turfgrass leaves at different irrigation rates was observed, yet irrigation rate was the major driver of turfgrass overall quality and health. Insights from this study will help to integrate recycled water with treatment and limited irrigation, thereby enhancing agricultural water reuse practices.

A qualitative risk assessment model for water reuse: Risks related to agricultural irrigation in Brazil

Urbanization and industrialization are increasing extreme weather events, causing water quantity and quality reduction. Global water scarcity impacts 32.5 % of the urban population and is growing. Brazil has also witnessed water scarcity, notably in the southeast (2014–2015) and south (2019–2020), with reservoirs dropping below 20 % capacity. Water reuse is vital for mitigating scarcity, though it presents risks due to contaminants. Risk analysis studies are crucial for evaluating contamination sources, pathways, and exposure scenarios in water reuse practices. Various methodologies, including quantitative, semi-quantitative, and qualitative analyses, can be employed. Given the uncertainty and diverse factors, qualitative methods are recommended for non-potable water reuse risk analysis. This work presents a qualitative risk analysis methodology that allows to evaluate non-potable water reuse categories. It assesses factors affecting human health and the environment, considering exposure scenarios, characteristics of the receptors, and sources of reused water. The risk analysis of water reuse was carried out focusing on agricultural reuse, considering as alternatives the irrigation of soybean and sugarcane crops. By reviewing literature, the probability of occurrence and the magnitude of impact of the risk factors were identified and rated, using an increasing relative numeric scale. This process resulted in an overall risk value for comparing agricultural irrigation alternatives. The obtained results indicate a promising risk analysis model that can be adjusted and applied to various water reuse modalities and key factors. This adaptable risk analysis model is mainly related to water treatment methods, prompting the proposal of risk control measures.

Water Reuse: A Comprehensive Review

Water scarcity has emerged as a pressing global concern, driven by population growth, urbanization, and climate change. As freshwater resources dwindle, the imperative for water reuse becomes increasingly apparent. Reusing water presents a sustainable solution to mitigate scarcity, offering a way to maximize the efficiency of available resources. This review delves into the multifaceted landscape of water consumption and reuse, aiming to provide a comprehensive analysis and understanding of this critical issue. It explores the diverse implications of unregulated water consumption, spanning from its impacts on household routines to its profound influence on economic activities. Additionally, it scrutinizes the legislative framework surrounding water usage, shedding light on the policies and regulations in place. Furthermore, the review investigates the current status of water reuse practices in Europe, delving into various methods of water recovery. Finally, it examines public perceptions and attitudes toward recycled water, offering insights into the societal outlook on this increasingly vital aspect of water management.

A perspective for the acceptance of water reuse: history of the valorization of wastewater throughout the development of society

Abstract Water reuse has been practiced for more than 5,000 years with different approaches by society throughout historical periods. We developed a concept that presents evidence and artistic-cultural manifestations about episodes of valorization (V), devaluation (D), and revaluation (R) of wastewater (WW) throughout history, called ‘Historical Development VxDxR/WW’. We conclude that WW has had a long valorization period of more than 3,500 years; the WW devaluation period lasted approximately 150 years; and in the last 100 years, there has been an attempt to revalue WW, with scientific, legal, and technological advances. We believe that a broad understanding of this concept can drive a true paradigm shift to guide public policies and appropriate decision-making, in the context of efficient water management. To guarantee a safe, sustainable, and economically viable water reuse practice, it is necessary to develop and implement a regulatory framework that involves, in addition to legal aspects, regional strategic planning and the production of social education instruments for the acceptance of water reuse. In this sense, this concept can pave the way for the necessary and expected advances.

Review of water reuse and recycling: USA successes vs. African challenges

This research paper conducts a comparative analysis of water reuse practices in the United States and water challenges in Africa. The United States exemplifies successful water reuse through advanced technologies, robust policies, and community engagement, while Africa contends with multifaceted challenges, including scarcity, pollution, and limited resources. The barriers to water reuse adoption in Africa, encompassing socioeconomic, institutional, and technological factors, underscore the need for targeted strategies. The paper recommends policy reforms, financial support, community engagement, technology transfer, research initiatives, and international collaboration to overcome these barriers. By recognizing the disparities and shared complexities, this research aims to contribute to developing context-specific solutions, fostering sustainable water reuse practices in Africa, and promoting equitable and resilient water management strategies globally.

The Future of Municipal Wastewater Reuse Concentrate Management: Drivers, Challenges, and Opportunities.

Water reuse is rapidly becoming an integral feature of resilient water systems, where municipal wastewater undergoes advanced treatment, typically involving a sequence of ultrafiltration (UF), reverse osmosis (RO), and an advanced oxidation process (AOP). When RO is used, a concentrated waste stream is produced that is elevated in not only total dissolved solids but also metals, nutrients, and micropollutants that have passed through conventional wastewater treatment. Management of this RO concentrate─dubbed municipal wastewater reuse concentrate (MWRC)─will be critical to address, especially as water reuse practices become more widespread. Building on existing brine management practices, this review explores MWRC management options by identifying infrastructural needs and opportunities for multi-beneficial disposal. To safeguard environmental systems from the potential hazards of MWRC, disposal, monitoring, and regulatory techniques are discussed to promote the safety and affordability of implementing MWRC management. Furthermore, opportunities for resource recovery and valorization are differentiated, while economic techniques to revamp cost-benefit analysis for MWRC management are examined. The goal of this critical review is to create a common foundation for researchers, practitioners, and regulators by providing an interdisciplinary set of tools and frameworks to address the impending challenges and emerging opportunities of MWRC management.

Impact of wastewater reuse on contaminants of emerging concern in an effluent-dominated river

Contaminants of emerging concern such as pharmaceuticals, personal care products, per- and polyfluoroalkyl substances, and plasticizers, are ubiquitous in effluent-dominated rivers and have potential adverse effects on humans and aquatic life. Demands on water supply have prompted conservation and water reuse measures, impacting the discharge in these rivers, yet the effects of these management decisions on water quality are largely intuited and not quantified. This research examines how changes in water reuse practices will impact concentrations of contaminants of emerging concern, specifically carbamazepine, diclofenac, galaxolide, gemfibrozil, 4-nonylphenol, and perfluorooctane sulfonic acid (PFOS), in the effluent-dominated Los Angeles River (Los Angeles County, California). A water quality module was added to a calibrated hydrologic model of the system and parametrized with observed water quality monitoring data in EPA SWMM. Results indicate that water reuse (i.e., reduced effluent flow) will consistently improve in-stream water quality for all compounds studied except PFOS. However, the improvements are often not substantial enough to mitigate high concentrations directly downstream of treated effluent discharge points. Concentrations of these pharmaceuticals are substantially reduced through attenuation as dilution and degradation occur downstream, though the rate of this attenuation is variable and based on the contaminant. In contrast, concentrations of PFOS increase under some wastewater reuse scenarios and decrease under others but remain below the recommended environmental screening levels. Our work also highlights that management decisions regarding water quantity should integrate water quality modeling to help identify priority monitoring locations and constituents.

Dissolved organic nitrogen removal from reclaimed water by enhanced coagulation, ozonation, and biodegradation

The presence of dissolved organic nitrogen (DON) in reclaimed water can pose adverse effects in water reuse practices, serving as a precursor of carcinogenic nitrogenous disinfection by-products (N-DBPs) and promoting membrane fouling. This study investigated DON removal by enhanced coagulation, ozonation, and ozonation/biodegradation at the lab and pilot scales. In the lab, enhanced coagulation by polyaluminum chloride (PACl) (60 mg/L) resulted in 46 ± 4 % DON removal. Lab-scale ozonation resulted in about 50 % reduction in DON over 2 h with a constant total nitrogen concentration. Biodegradation studies revealed <15 % DON removal, but ozonation combined with biodegradation achieved >30 % DON removal. At the pilot scale, enhanced coagulation by 56 mg/L of PACl plus 4 mg/L aluminum chlorohydrate resulted in 36 ± 8 % and 27 ± 9 % DON removal from secondary and filter effluent, respectively. Pilot-scale ozonation followed by biological active carbon (BAC) removed DON by 40 ± 6 % and 42 ± 5 %, respectively, from secondary and filter effluent. Dissolved organic carbon was also significantly removed by enhanced coagulation (23 ± 7 % and 20 ± 13 % from secondary and filter effluent, respectively) and by ozonation/BAC (39 ± 6 % and 39 ± 3 % from secondary and filter effluent, respectively) treatment.

Insights into Global Water Reuse Opportunities

The growing population, intensified anthropogenic pressures and climate variability have increased the demands on available water resources, and water reuse has become a high priority, particularly in areas of the world suffering from water stress. The main objectives of this review paper are to consider and identify the potential opportunities and challenges in the implementation of water reuse schemes worldwide by considering and analyzing different fields of interest in water reuse, the current and future global drivers of water reuse policies, the existing advances in treatment and reuse technologies promising elimination of environmental footprint and human health risk, an analysis of the trends in potable and non-potable reuse, and the development of quality criteria and issues related to transition circular economy. Moreover, the major knowledge gaps in critical issues on different domains of water reuse schemes are discussed. For this study, a thorough analysis of the current literature was conducted, using research and review articles, technical reports, specific national (and EU) proposals, guidance documents, and legislative initiatives and actions, as well as any validly disseminated findings by scientists around the world in the wider scientific area of (alternative) water resources, water supply, water management, sustainable development, and protection of public health. Water reuse practices are expected to increase in the future, mainly in developed countries and climate-vulnerable areas of the planet. Current advances in wastewater treatment and water reuse technologies can provide the opportunity for the foul exploitation of alternative water resources, increasing the potential of potable and non-potable water reuse systems worldwide, relying on pollutant/contaminant elimination, and improving economic and energy performances. Moreover, paradigmatic and technological switches based on an improved understanding of the relationships between the water cycle and the Water–Energy–Food (WEF) Nexus will increase the perspective of water reuse schemes. The benefits of the recovery of nutrients through sewage wastewater treatment are also highlighted, arising from reduced costs associated with their sheer removal and the supplement of fertilizers to the WEF Nexus. On the other hand, reduced nutrient removal may promote agricultural or landscape reuse practices, contributing to less energy consumption and reducing GHGs emissions. Regarding the management of water use schemes, a holistic approach (integrated management) is proposed, incorporating regulatory actions, actions increasing public awareness, interconnection among actors/stakeholders, and efficient control and monitoring. The establishment of quality criteria is paramount to preventing undesirable impacts on humans and the environment. The study considers the “one water” concept, which means equal water quality criteria independent of the origin of water, and instead differentiates among different types of water reuse as a means to facilitate implementation and management of potable and non-potable water reuse. Finally, it highlights the need to understand the impacts of water reuse systems on ecosystem services (ESs) and the consequences of achieving the global sustainable development goals (SDGs).

Reverse osmosis membrane functionalized with aminated graphene oxide and polydopamine nanospheres plugging for enhanced NDMA rejection and anti-fouling performance

The use of reverse osmosis (RO) for water reclamation has become an essential part of the water supply owing to the ever-increasing water demand and the utmost performance of the RO membranes. Despite the global RO implementation, its inferior rejection against low molecular weight contaminants of emerging concerns (CECs) (i.e., N-nitrosodimethylamine (NDMA)) and propensity to fouling remain bottle-neck thus affecting process robustness for water reuse. This study aims to enhance both the rejection and antifouling properties of the RO membrane. Herein for the first time, we report RO membrane modification using polydopamine nanospheres (PDAns) followed by aminated-graphene oxide (AGO) deposition as an effective approach to overcome these challenges. The modification of the RO membrane using PDAns-AGO resulted in 89.3 ± 2.7% rejection compared to the pristine RO membrane which demonstrated 69.2 ± 2.1% NDMA rejection. This significant improvement can be ascribed to the plugging and shielding of defective areas (formed during interfacial polymerization) of the polyamide layer through active PDAns and AGO layers and to the added sieving mechanism that arose through narrow channels of the AGO owing to its reduction. Moreover, the in-situ and non-destructive fouling monitoring using optical coherence tomography (OCT) revealed that the PDAns-AGO coating enhanced both the anti-scaling and anti-biofouling characteristics. The improved hydrophilicity and bactericidal effect together with roughness and surface charge suppression synergistically enhanced anti-fouling properties. This study provides a new direction for safe and cost-effective water reuse practices. The membrane with high selectivity against CECs such as NDMA has the potential to eliminate permeate staging using second pass RO and other advanced oxidation processes which are utilized as a tertiary treatment to make reclaimed water suitable for potable/non-potable application.

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.

Methodology for a preliminary assessment of water use sustainability in industries at sub-basin level

The sustainability of industrial production, especially for highly water-demanding processes, is strictly related to water resource availability and to the dynamic interactions between natural and anthropogenic requirements over the spatial and temporal scales. The increase in industrial water demand raises the need to assess the related environmental sustainability, facing the occurrence of global and local water stress issues. The identification of reliable methodologies, based on simple indices and able to consider the impact on local water basins, may play a basilar role in water sustainability diagnosis and decision-making processes for water management and land use planning. The present work focalized on the definition of a methodology based on the calculation of indicators and indices in the view of providing a synthetic, simple, and site-specific assessment tool for industrial water cycle sustainability. The methodology was built starting from geo-referenced data on water availability and sectorial uses derived for Italian sub-basins. According to the data monthly time scale, the proposed indices allowed for an industrial water-related impacts assessment, able to take into account the seasonal variability of local resources. Three industrial factories, located in northern (SB1, SB2) and central (SB3) Italian sub-basins, were selected as case studies (CS1, CS2, CS3) to validate the methodology. The companies were directly involved and asked to provide some input data. The methodology is based on the calculation of three synthetic indexes: the Withdrawal and Consumption water Stress Index (WCSI) allowed for deriving a synthetic water stress level assessment at the sub-basin scale, also considering the spatial and temporal variations; the industrial water use sustainability assessment was achieved by calculating the Overall Factory-to-Basin Impact (OFBI) and the Internal Water Reuse (IWR) indices, which allowed a preliminary evaluation of the factories' impacts on the sub-basin water status, considering the related water uses and the overall pressures on the reference territorial context. The WCSI values highlighted significant differences between the northern sub-basins, characterised by limited water stress (WCSISB1 = 0.221; WCSISB2 = 0.047), and the central ones, more subjected to high stress (WCSISB3 = 0.413). The case studies CS1 and CS3 showed to exert a more significant impact on the local water resource (OFBICS1 = 0.18%; OFBICS2 = 0.192%) with respect to CS2 (OFBI = 0.002%), whereas the IWR index revealed the different company's attitude in implementing water reuse practices (IWRCS1 = 40%; IWRCS1 = 27%; IWRCS1 = 99%). The proposed methodology and the indices may also contribute to assessing the effectiveness of river basin management actions to pursue sustainable development goals.

La reutilización del agua en el ámbito de la economía circular y sostenibilidad

El presente artículo tiene como propósito dar luz sobre la consolidación de la reutilización del agua en el ámbito de la economía circular en Brasil, destacando experiencias en España, como recurso estratégico convencional y contribuidor para la efectividad de la sostenibilidad. El presente estudio está dividido en dos momentos: el primero trata sobre la realidad brasilera sobre la reutilización del agua en la Economía Circular. El segundo trata sobre las contribuciones de España sobre las aguas residuales, como factor contribuidor para la efectivización de la Sostenibilidad. Se concluye que la reutilización del agua es un modelo de referencia útil en Brasil, aunque poco aplicado. El po-tencial de reutilización es un hecho indiscutible, pero su consolidación como recurso estratégico convencional es un desafío que fuerza a todos los actores a accionar de forma coordinada y con rigidez en el planeamiento de acciones futuras. La experiencia española en este sector está muy avanzada, en la cual los actores involucrados contribuyen para la concreción de este proceso, hay un aparato normativo y administrativo estructurado, mientras que Brasil care-ce de legislación específica. En cuanto a la metodología, fue utilizada la base lógica inductiva por medio de la investigación bibliográfica y documental.

Actor Roles and Networks in Implementing Urban Water Innovation: A Study of Onsite Water Reuse in the San Francisco Bay Area.

As climate change and rapid urbanization stress our aging water infrastructure, cities are under increasing pressure to develop more flexible, resilient, and modular water management systems. In response, onsite water reuse practices have been adopted by several cities globally. In addition to technological innovation, these novel water treatment systems also require new stakeholder collaborations, relationships, and processes to support them. There are, however, few models for stakeholder arrangements that support and encourage the adoption and success of such infrastructure. In this paper, we use interviews with stakeholders involved in onsite water reuse projects in the San Francisco Bay Area to create a social network map that describes the interactions between stakeholders at large and during specific phases of project implementation. Using qualitative content analysis of expert interviews and social network analysis, we identify four actor roles that are key to the functioning of this novel water infrastructure paradigm─specialists, continuity providers, program champions, and conveners─and discuss the importance of each role through the course of project implementation. These findings can be helpful for policy interventions and outreach efforts by other cities and communities looking to implement onsite water systems.

Assessment of the Potential for Reuse of Water in the Supply of the Metropolitan Region of São Paulo

The phenomenon of water scarcity has become a global problem, which among its main causes is the growth of the population that brings as a consequence an increasing demand for potable water, which is an admittedly limited resource. São Paulo, the greatest example of inequality in water distribution in Brazil with 22% of the population and only 1.6% of the country’s surface water, faced between 2014 and 2016 one of the biggest supply crises in its history, characterized mainly by the lack of rains. The work evaluated the current situation of reuse water use in the Metropolitan Region of São Paulo (MRSP) and interviews were carried out with specialists in the water resources sector, forming a representative tripod that involves the concessionaire of public water and sewage services, teaching institutions that study and research the topic and civil society entities responsible for managing the water resources that supply the city of São Paulo and 17 other municipalities in its surroundings. The study identified that much still needs to be done, necessarily counting on the active participation of the public power that has the largest structure to manage and encourage the practice of water reuse, that actions will be necessary to improve the legislation, so it is important that there is a permanent dialogue around the theme so that an alternative for water supply is available that meets the needs of society and collaborates with the sustainability of the planet.

N-Nitrosamines and their precursors in wastewater effluents from selected industries in Spain

N-nitrosamines (NAs), and N-nitrosodimethylamine (NDMA) in particular, are hazardous disinfection byproducts (DBPs) relevant when wastewater impacts drinking water sources and, in water reuse practices. Our study investigates the concentrations of NDMA and five additional NAs and their precursors in industrial wastewater effluents. Aiming to identify potential differences between industrial typologies, wastewaters from 38 industries belonging to 11 types of the UN International Standard Industrial Classification of All Economic Activities system (ISIC) were analysed. Results show that the presence of most NAs and their precursors cannot be linked to a specific industry type as these were in general very different within the classes. Nevertheless, N-nitrosomethylethylamine (NMEA) and N-nitrosopiperidine (NPIP) as well as precursors for N-nitrosodiethylamine (NDEA), NPIP and N-nitrosodibuthylamine (NDBA) could be rank with different concentrations between ISIC classes (p-value < 0.05). Specific industrial wastewater with notable high concentrations of NAs and their precursors were identified too. The effluents with the highest concentration of NDMA belong to the ISIC C2011 class (Manufacture of basic chemical), while the effluents with the highest concentration of NDMA precursors were from the ISIC C1511 class (Tanning and dressing of leather; dressing and dyeing of fur). Other relevant NAs found were NDEA in ISIC class B0810 (Quarrying of stone, sand, and clay) and ISIC class C2029 (Manufacture of other chemical products).

Analytical upgrade of a methodology based on UHPLC-MS/MS for the analysis of endocrine disrupting compounds in greywater

A multi-residue analytical methodology for the determination of 25 endocrine disrupting compounds (EDCs), encompassing various chemical classes (hormones, antimicrobials, preservatives, plasticizers, stimulants, alkylphenolic compounds, anticorrosives, and organophosphorus flame retardants), has been upgraded for the analysis of greywater. The methodology is based on solid phase extraction (SPE) followed by ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The optimized methodology achieved recoveries between 63% and 146% for all compounds, with MDLs ranging from 0.3 to 141 ng/L. Most of the compounds showed a pronounced signal suppression in the laundry greywater tested, and therefore, quantification was performed with a matrix-matched calibration curve to surpass the matrix effects observed (between -100% and 106%). Additionally, polyvinylidene fluoride (PVDF) membrane filters were selected among several filter types as the most suitable for greywater filtration. The upgraded methodology allowed the detection of 14, four and four EDCs in laundry, kitchen and shower/sink greywater, respectively. Caffeine was the only compound detected in all types of greywater, showing the highest concentrations (&gt; 40,000 ng/L in kitchen greywater, and 2,360 ng/L in laundry greywater), followed by methylparaben and 1H-benzotriazole (1,607 and 776 ng/L, respectively, in laundry greywater). This analytical methodology constitutes an important tool for monitoring different families of contaminants in greywater, a poorly studied matrix, which is nowadays being considered as a future source of freshwater, contributing to overcoming problems of water scarcity. Water monitoring thus helps to guarantee water quality in water reuse practices and to understand EDC exposure patterns and their potential environmental impact.

Drainage water reuse strategies: Case of El-Bats drain, Fayoum Governorate, Egypt

Several challenges facing the water resources managers in many Egyptian governorates that suffer from rapid growth and unbalanced distribution of population. Typically, these governorates need to supplement their limited water resources by filling the gap between water supply and demand. This research aims to evaluate the opportunities to expand the drainage water reuse (DWR) practice in Fayoum Governorate (FG) region. El-Bats drain which lies in the Eastern part of Fayoum region was evaluated for the possible DWR. Intensive sampling campaigns were carried out during the period from 2009 to 2018 to analyze 14 water quality parameters (WQPs) covering agricultural, domestic and industrial pollution levels. Different univariate and multivariate statistical tools were employed to assess the collected sampling data including descriptive statistics, percentile analysis, hierarchal cluster analyses as well as mass balance computation for pollution loads. The obtained results showed the capability of some reaches of El-Bats drain for DWR in irrigation after mixing with canal fresh water by variable mixing ratios. In addition, the need for employing proper treatment facilities in other reaches.

Analysis of Regulatory Framework for Produced Water Management and Reuse in Major Oil- and Gas-Producing Regions in the United States

The rapid development of unconventional oil and gas (O&amp;G) extraction around the world produces a significant amount of wastewater that requires appropriate management and disposal. Produced water (PW) is primarily disposed of through saltwater disposal wells, and other reuse/disposal methods include using PW for hydraulic fracturing, enhanced oil recovery, well drilling, evaporation ponds or seepage pits within the O&amp;G field, and transferring PW offsite for management or reuse. Currently, 1–2% of PW in the U.S. is used outside the O&amp;G field after treatment. With the considerable interest in PW reuse to reduce environmental implications and alleviate regional water scarcity, it is imperative to analyze the current regulatory framework for PW management and reuse. In the U.S., PW is subject to a complex set of federal, state, and sometimes local regulations to address the wide range of PW management, construction, and operation practices. Under the supervision of the U.S. Environment Protection Agency (U.S. EPA), different states have their own regulatory agencies and requirements based on state-specific practices and laws. This study analyzed the regulatory framework in major O&amp;G-producing regions surrounding the management of PW, including relevant laws and jurisdictional illustrations of water rules and responsibilities, water quality standards, and PW disposal and current/potential beneficial reuse up to early 2022. The selected eastern states (based on the 98th meridian designated by the U.S. EPA as a tool to separate discharge permitting) include the Appalachian Basin (Marcellus and Utica shale areas of Pennsylvania, Ohio, and West Virginia), Oklahoma, and Texas; and the western states include California, Colorado, New Mexico, and Wyoming. These regions represent different regulations; climates; water quantities; quality diversities; and geologic, geographic, and hydrologic conditions. This review is particularly focused on the water quality standards, reuse practices and scenarios, risks assessment, knowledge gaps, and research needs for the potential reuse of treated PW outside of O&amp;G fields. Given the complexity surrounding PW regulations and rules, this study is intended as preliminary guidance for PW management, and for identifying the knowledge gaps and research needs to reduce the potential impacts of treated PW reuse on the environment and public health. The regulations and experiences learned from these case studies would significantly benefit other states and countries with O&amp;G sources for the protection of their environment and public health.