Water Reuse Practices Research Articles

Water reuse in industries: analysis of opportunities in the Paraíba do Sul river basin, a case study in Presidente Vargas Plant, Brazil.

In recent years, the demand for clean water has been growing all over the world despite the different threats posed, including increasing pollution, increasing deforestation and climate change. Industrial activity is the second largest consumer of water, so highly industrialized regions are more susceptible to water stress. In this sense, reuse strategies have been progressively discussed and used around the world; however, in Brazil there is still place for many advances, whether due to lack of incentives, cultural issues in society, or poor regulation of the subject. The objective of this work was to carry out a diagnosis of raw water uptake by industries in one Hydrographic Region of the state of Rio de Janeiro and to propose a discussion on the adoption of water reuse practices for non-potable purposes from the use of treated effluents. A survey of the theoretical framework on the subject was carried out, as well as an analysis of sustainability indicators and reports of the companies, including the current licensing processes of large undertakings consuming water resources. With this study, it was possible to obtain the average cost of implementing a water reuse unit for an industry in the state of Rio de Janeiro-Brazil, which, despite still being expensive, has a strong tendency to use due to world water shortages. Finally, it was concluded that the state of Rio de Janeiro has a threat of water scarcity that could be aggravated in the coming years, if measures and investments in supply alternatives are not adopted (water reuse), and improvement in all stages of water management water resources.

Wastewater Treatment Plants in Mediterranean Spain: An Exploration of Relations between Water Treatments, Water Reuse, and Governance

Wastewater treatment plants (WWTPs) are fundamental to enable the transition towards the principles of a circular economy in water supply. In Mediterranean Spain, an area with recurrent episodes of water stress, treated wastewater may become a critical resource for the future. However, its incorporation into the array of potential water options opens up questions regarding the different qualities obtained with each treatment, the extent of existing water reuse practices, or the governance regime of plants. In this paper, the state of WWTPs in Mediterranean Spain is analyzed, with focus on plant sizes, treatment technologies, water use, and governance regimes. The latter shows a strong presence of private WWTPs and a lesser extent of public–private WWTPs, while the number of public plants is small. Regarding treatment technologies, the most sophisticated systems are found in public–private plants that are also the largest in size. Reclaimed water is very significant for agricultural and golf course irrigation in some areas (Valencia, Murcia, Andalusia), but still relatively incipient for other uses.

Understanding Microbial Loads in Wastewater Treatment Works as Source Water for Water Reuse.

Facing challenges in water demands and population size, particularly in the water-scarce regions in the United States, the reuse of treated municipal wastewater has become a viable potential to relieve the ever-increasing demands of providing water for (non-)potable use. The objectives of this study were to assess microbial quality of reclaimed water and to investigate treatability of microorganisms during different treatment processes. Raw and final treated effluent samples from three participating utilities were collected monthly for 16 months and analyzed for various microbial pathogens and fecal indicator organisms. Results revealed that the detectable levels of microbial pathogens tested were observed in the treated effluent samples from all participating utilities. Log10 reduction values (LRVs) of Cryptosporidium oocysts and Giardia cysts were at least two orders of magnitude lower than those of human adenovirus and all fecal indicator organisms except for aerobic endospores, which showed the lowest LRVs. The relatively higher LRV of the indicator organisms such as bacteriophages suggested that these microorganisms are not good candidates of viral indicators of human adenovirus during wastewater treatment processes. Overall, this study will assist municipalities considering the use of wastewater effluent as another source of drinking water by providing important data on the prevalence, occurrence, and reduction of waterborne pathogens in wastewater. More importantly, the results from this study will aid in building a richer microbial occurrence database that can be used towards evaluating reuse guidelines and disinfection practices for water reuse practices.

Análise da importância do reuso da água em lavanderias de beneficiamento de jeans

As lavanderias de Beneficiamento de Jeans, são consideradas indústrias com uma alta capacidade poluidora e hidro intensivas, devido aos produtos químicos utilizados durante os processos produtivos, e que demandam uma grande quantidade de água para o beneficiamento das peças. Nesse cenário há necessidades de estudos que apontem alternativas de reuso da água, como também diversificação na sua forma de captação. A presente pesquisa tem como objetivo analisar o reuso de águas nas lavanderias localizadas no Arranjo Produtivo Local de Confecções do Agreste Pernambucano (APLCAPE), de forma a contribuir para as alternativas de reuso durante o processo produtivo. Para levantamento dos dados, foram aplicados questionários e entrevistas em 105 lavanderias, onde foi possível determinar e conhecer o processo produtivo, uso da água e possibilidades de reuso. Verificou-se que 83% das lavanderias realizam níveis diferentes de reuso água e 17% não fazem qualquer tipo de reuso. Não obstante, os resultados demostraram que a prática do reuso de água, além de contribuir para a economia de água no processo, traz uma economia financeira considerável, uma vez que a maioria das lavanderias utilizam água compradas de caminhão pipa, o que interfere no custo e na competividade do produto.

Public Acceptance of Water Reuse for Agriculture in the Wake of the New EU Regulation: Early Reflections

Abstract Domestic wastewater reuse in agriculture is often discussed as a way to tackle water scarcity in Europe. Europe could learn from the examples of other countries that are already successfully implementing wastewater reuse, especially in the Mediterranean. However, the potential of the practice is currently unfulfilled mainly due to social and legal barriers, including public resistance and the lack of a unified legislative framework at the European Union (EU) level. In the wake of the new EU Water Reuse Regulation released in June 2020, we wonder how this legislative intervention can foster public acceptance of non-conventional water reuse practices in agriculture. The original contribution of this piece is to provide a novel discussion of the transformations potentially triggered by the new EU Regulation and to suggest an innovative way forward, based on engaging interested users in water quality monitoring (i.e. water citizen science). We combine theoretical and empirical analysis, grounding our findings in an overarching theoretical concept, i.e. the neo-institutionalism theory. We conclude that the main catalysts for stimulating public acceptance can be identified in a unifying legislative tool represented by the recent EU Regulation and in the promotion of participatory water monitoring initiatives, also in line with the spirit of the EU Regulation.

Assuring water quality along multi-barrier treatment systems for agricultural water reuse

Abstract Based on three pilot- and demonstration-scale projects investigating agricultural irrigation practices with reclaimed water, risks associated with these water reuse practices are highlighted and processes and strategies to minimize associated microbial risks were evaluated. A number of treatment processes and combinations were tested regarding their efficacy for pathogen removal, representing the biggest threat to the quality of products from reuse irrigation practices. In addition, the importance of regrowth potential and different methods for monitoring risks associated with pathogens were discussed. One method for online monitoring is flow cytometry. The results of an exemplary quantitative microbial risk assessment (QMRA) were discussed to determine the significance of microbial risks. Multi-barrier approaches comprised of technical and administrative barriers can reduce the risks of water reuse significantly. Quality management also needs to address all stakeholders involved in a reuse project, starting from source control in the sewershed to marketing of the final products. In addition, environmental risks of water reuse need to be addressed by quality management as well.

The use of purified waste water for agricultural irrigation

Agricultural production is highly dependent on water and is also the largest consumer. In developing countries, on the other hand, rapid urbanisation has led to increased volumes of wastewater being used as a low-cost alternative to conventional irrigation, turning a 'waste' into a new resource to support local agriculture. The re-use of water could thus potentially reduce the need for supplementary applications of inorganic fertiliser. End-users should be informed of the nutrient content of purified water.In the field of purified wastewater, it is not only necessary to make the use of this new resource possible, but also to increase social acceptability by overcoming technical, economic, political and social barriers in order to make greater use possible. Government and research activities should demonstrate the benefits of using purified wastewater and the limitations of doing so, although again such efforts would need to be funded. European geography and climate lead to a disparity in the distribution of water in the EU, in fact we observe a European Union in two gears, a Central Europe rich in water resources and therefore without commercial economic interests in recycling residual water, while a Southern Europe at risk of desertification and interested in a clear, rational and pragmatic regulation of water resources to minimize waste. More than 60% of the water used in Southern Europe is for irrigation, with extraction peaks of up to 80% in some watersheds. The opportunity to use purified urban and industrial wastewater for agricultural irrigation is therefore the most effective strategy to combat drought, a consequence of climate change. Currently, the practice of water reuse is established in only a few Member States and is implemented far below its potential. To facilitate and stimulate the reuse of water for agricultural irrigation, the EU has issued the Regulation on Minimum Requirements for Reuse, setting minimum requirements for purified water quality and monitoring, assigning crucial risk management tasks, and introducing a harmonized approach for the reuse of irrigation water across the EU. The new rules will increase legal certainty in this field, where currently the rules vary widely from one Member State to another.

Niobium Oxide Catalysts as Emerging Material for Textile Wastewater Reuse: Photocatalytic Decolorization of Azo Dyes

Niobium-based metal oxides are emerging semiconductor materials with barely explored properties for photocatalytic wastewater remediation. Brazil possesses the greatest reserves of niobium worldwide, being a natural resource that is barely exploited. Environmental applications of solar active niobium photocatalysts can provide opportunities in the developing areas of Northeast Brazil, which receives over 22 MJ m2 of natural sunlight irradiation annually. The application of photocatalytic treatment could incentivize water reuse practices in small and mid-sized textile businesses in the region. This work reports the facile synthesis of Nb2O5 catalysts and explores their performance for the treatment of colored azo dye effluents. The high photoactivity of this alternative photocatalyst makes it possible to quickly obtain complete decolorization, in less than 40 min of treatment. The optimal operational conditions are defined as 1.0 g L−1 Nb2O5 loading in slurry, 0.2 M of H2O2, pH 5.0 to treat up to 15 mg L−1 of methyl orange solution. To evaluate reutilization without photocatalytic activity loss, the Nb2O5 was recovered after the experience and reused, showing the same decolorization rate after several cycles. Therefore, Nb2O5 appears to be a promising photocatalytic material with potential applicability in wastewater treatment due to its innocuous character and high stability.

Characterization of implementation limits and identification of optimization strategies for sustainable water resource recovery through life cycle impact analysis

How we manage alternative freshwater resources to close the gap between water supply and demand is pivotal to the future of the environment and human well-being. Increased scarcity of water for agricultural irrigation in semi-arid and arid regions has resulted in a growing interest in water reuse practices. However, insight into the life cycle impacts and potential trade-offs of these emerging practices are still limited by the paucity of systematic evaluations of different water reuse implementations. In this study, a host of environmental and human health impacts at three implementation levels of allowing water reclamation for crop irrigation was comparatively evaluated across the operational landscape via a combination of scenario modelling, life-cycle impact analyses and Monte Carlo simulations. Net harvesting of reclaimed water for irrigation was found to be dependent upon the sophistication of the treatment processes, since multistage and complex configurations can cause greater direct water consumption during processing. Further, the direct benefits of water resource recovery can be essentially offset by indirect adverse impacts, such as mineral depletion, global warming, ozone depletion, ecotoxicity, and human health risks, which are associated with increased usage of energy and chemicals for rigorous removal of contaminants, such as heavy metals and contaminants of emerging concern. Nonetheless, expanded simulations suggest the significance of concurrently implementing energy recovery, nutrient recycling, and/or nature-based, chemical-free water technologies to reduce the magnitude of negative impacts from engineered water reclamation processes.

Greywater irrigation as a source of organic micro-pollutants to shallow groundwater and nearby surface water

Increased water demands due to population growth and increased urbanisation have driven adoption of various water reuse practices. The irrigation of greywater (water from all household uses, except toilets) has been proposed as one potential sustainable practice. Research has clearly identified environmental harm from the presence of micro-pollutants in soils, groundwater and surface water. Greywater contains a range of micro pollutants yet very little is known about their potential environmental fate when greywater is irrigated to soil. Therefore, this study assessed whether organic micro-pollutants in irrigated greywater were transferred to shallow groundwater and an adjacent surface waterway. A total of 22 organic micro-pollutants were detected in greywater. Six of these (acesulfame, caffeine, DEET, paracetamol, salicylic acid and triclosan) were selected as potential tracers of greywater contamination. Three of these chemicals (acesulfame, caffeine, DEET) were detected in the groundwater, while salicylic acid was also detected in adjacent surface water. Caffeine and DEET in surface water were directly attributable to greywater irrigation. Thus the practice of greywater irrigation can act as a source of organic micro-pollutants to shallow groundwater and nearby surface water. The full list of micro-pollutants that could be introduced via greywater and the risk they pose to aquatic ecosystems is not yet known.

Advancing Agricultural Water Security and Resilience Under Nonstationarity and Uncertainty: Evolving Roles of Blue, Green, and Grey Water

Advancing Agricultural Water Security and Resilience Under Nonstationarity and Uncertainty: Evolving Roles of Blue, Green, and Grey Water

Commentary: Perspectives on aquaculture, urbanization and water quality

Aquaculture presents essential opportunities to meet global food security needs, but adverse effects of aquaculture practices on ecological integrity and influences of existing waste management infrastructure on product safety must be understood in rapidly expanding urban and peri-urban regions. Concentration of, access to and use of chemical products is increasing in many urban areas faster than interventions are being implemented. Aquaculture farming is employing “non-traditional” (e.g., treated or untreated sewage) waters in some regions, but the spatial extent of these intentional or de facto water reuse practices with associated water quality and food safety systems are poorly understood around the world. Integrative water reuse, aquaculture product safety, ecological and public health research and advanced surveillance systems are needed. Such efforts appear particularly important because noncommunicable diseases are increasing and pollution is now recognized as one of the major global health threats, particularly in lower and middle income countries. Here we provide some modest perspectives and identify several research needs to support more sustainable aquaculture practices while protecting public health and the environment.

A dynamic transport model for quantification of norovirus internalization in lettuce from irrigation water and associated health risk

Food production using recycled wastewater offers a sustainable way forward in light of limited freshwater resources. However, concerns of food safety should be addressed to protect public health. To this end, we developed a dynamic transport model to track norovirus from the irrigation water to the root and shoot of lettuce during the growth period. These processes were embodied in a system of ordinary differential equations that also incorporated plant growth, transpiration rate, viral attachment and detachment to culture media, viral decay, and plant barrier effects. Model parameters were either obtained from the literature or through fitting the model to experimental data from a study reporting human norovirus transport in hydroponically grown lettuce. The results showed that lettuce grown hydroponically resulted in a higher risk than lettuce grown in soil. In both cases, the risk predicted failed to meet the risk benchmarks established by the U.S. EPA and WHO. Viral attachment to growth media, such as the soil particles, was an important mechanism for risk reduction. A sensitivity analysis revealed that harvesting time and irrigation time are important factors influencing the viral loads in lettuce. Hence, this pathogen transport model provides a framework for investigating the effects of time and other factors on disease burdens from water reuse in agriculture, underscoring the utility of a dynamic model. In the absence of a routine monitoring of contaminants in the recycled irrigation water and food crops, a quantitative risk assessment based on objective scientific knowledge is the best approach to guide the policy decisions on water reuse practices.

Governing Non-Potable Water-Reuse to Alleviate Water Stress: The Case of Sabadell, Spain

The world will experience an estimated 40% freshwater supply shortage by 2030, converting water scarcity into one of the principal global challenges that modern society faces. Urban water reuse is recognized as a promising and necessary measure to alleviate the growing water stress in many regions. The transformation to widespread application of water-reuse systems requires major changes in the way water is governed, and countries such as Spain already find themselves involved in this process. Through the systematic assessment of the city of Sabadell (Spain), we aim to identify the main barriers, opportunities and transferable lessons that can enhance governance capacity to implement systems for non-potable reuse of treated wastewater in cities. It was found that continuous learning, the availability and quality of information, the level of knowledge, and strong agents of change are the main capacity-building priorities. On the other hand, awareness, multilevel network potential and implementing capacity are already well-established. It is concluded that in order to undertake a widespread application of water-reuse practices, criteria examining water quality according to its use need to be developed independently of the water’s origin. The development and implementation of such a legislative frame should be based on the experience of local water-reuse practices and continuous evaluation. Finally, the need for public engagement and adequate pricing mechanisms are emphasized.

Special Issue on Wastewater Treatment and Reuse Technologies

Wastewater treatment allows for the safe disposal of municipal and industrial wastewater to protect public health and the ecosystem[...]

A mathematical model to plan for long-term effects of water conservation choices on dry weather wastewater flows and concentrations

In many cities, sewer systems are experiencing conditions that are significantly different from those for which they were designed. Factors such as water conservation efforts, changes in population, and efforts to reduce infiltration are altering the quantity and quality of sewage. These changes may affect the ability of sewers to maintain self-cleansing velocities, which are crucial to avoiding solids settling and corrosion issues. Further, such changes may alter the timeline for expected wastewater plant expansion. The present work proposes a method for predicting average annual dry weather wastewater flow, as well as pollutant load and concentration over time. The method takes into account potential declines in per person wastewater production due to water conservation and reuse practices, as well as other potential changes such as shifts in population, transformations in industrial wastewater production, and variations in dry weather infiltration. Results show that the amount of dry weather infiltration will play a large role in whether or not conservation will affect self-cleansing velocities or plant expansions. Conservation is most beneficial to systems with high levels of dry weather infiltration since plant expansion could be avoided; and most detrimental to systems with low levels of infiltration since low flow conditions could lead to settling and corrosion in the sewer. Furthermore, the rate of implementation of conservation efforts influences when impacts to the system would occur. Utility planners will be able to use this method to predict treatment plant upgrade and expansion needs more accurately as well as to assess the relative value of utility-based maintenance activities and conservation practices.

A remote sensing method for estimating regional reservoir area and evaporative loss

Evaporation from the water surface of a reservoir can significantly affect its function of ensuring the availability and temporal stability of water supply. Current estimations of reservoir evaporative loss are dependent on water area derived from a reservoir storage-area curve. Such curves are unavailable if the reservoir is located in a data-sparse region or questionable if long-term sedimentation has changed the original elevation-area relationship. We propose a remote sensing framework to estimate reservoir evaporative loss at the regional scale. This framework uses a multispectral water index to extract reservoir area from Landsat imagery and estimate monthly evaporation volume based on pan-derived evaporative rates. The optimal index threshold is determined based on local observations and extended to unobserved locations and periods. Built on the cloud computing capacity of the Google Earth Engine, this framework can efficiently analyze satellite images at large spatiotemporal scales, where such analysis is infeasible with a single computer. Our study involves 200 major reservoirs in Texas, captured in 17,811 Landsat images over a 32-year period. The results show that these reservoirs contribute to an annual evaporative loss of 8.0 billion cubic meters, equivalent to 20% of their total active storage or 53% of total annual water use in Texas. At five coastal basins, reservoir evaporative losses exceed the minimum freshwater inflows required to sustain ecosystem health and fishery productivity of the receiving estuaries. Reservoir evaporative loss can be significant enough to counterbalance the positive effects of impounding water and to offset the contribution of water conservation and reuse practices. Our results also reveal the spatially variable performance of the multispectral water index and indicate the limitation of using scene-level cloud cover to screen satellite images. This study demonstrates the advantage of combining satellite remote sensing and cloud computing to support regional water resources assessment.

How Governance Regimes Shape the Implementation of Water Reuse Schemes

The governance dimensions of water reuse scheme development and operation, such as policies and regulatory frameworks, and public involvement and stakeholder collaboration, can serve to both facilitate and constrain wider adoption of water reuse practices. This paper explores the significance and underlying structure of the key governance challenges facing the water reuse sector in Europe. It presents empirical evidence from interviews and focus group sessions conducted at four water reuse schemes: an indirect potable reuse scheme at Torreele (Belgium), the urban reuse of treated municipal wastewater at the London Olympic Park (United Kingdom) and at Sabadell (Spain), and the reuse of agro-industrial effluent for irrigation at Capitanata (Italy). The findings underscore the importance of clarity in policy arrangements around water reuse, as well as of the financial competitiveness of reuse projects compared to alternative water supply options. Operators of water reuse schemes expressed a preference for water quality standards, which focus on appropriateness for use rather than over-emphasise the waters’ origin so that unnecessary treatment and costs can be avoided. Positive public support was widely acknowledged as an important factor in the success or failure of water reuse schemes. We conclude that constructive institutional relationships underpin many of the challenges faced by reuse scheme operators and that greater emphasis should be given to building confidence and gaining trust in water service providers through early identification of how governance regimes shape the viability of new schemes.

Near Real-Time Flow Cytometry Monitoring of Bacterial and Viral Removal Efficiencies during Water Reclamation Processes

Wastewater reuse has become an important part of the urban water supply portfolio in water stressed regions. Effective wastewater treatment processes are critical to protect public health during water reuse practices. However, the microbial removal efficiencies in wastewater reclamation plants are not routinely monitored due to the lack of a simple quantification method. This study applied a near real-time flow cytometry (FCM) technique to quantify the removal of total bacteria and viruses at three wastewater reclamation plants in Southern California. The results showed that the activated sludge process removed 1–2 log10 of bacteria but was not efficient at removing viruses. The membrane bioreactor process was capable of removing both bacteria and viruses with high efficiency. At the plant using chloramines as the main disinfectant, even though culturable total coliform bacteria were effectively reduced to the level meeting the California Title 22 Water Recycling Criteria (7-day median of 2.2 most probable number (MPN)/100 mL, and no more than one sample exceeds 23 MPN/100 mL), the disinfected final effluent still contained greater than 106 bacterial and 108 viral particles per mL in. In contrast, more than 4 log10 removal of both bacteria and viruses were observed at the plant using free chlorine as the main disinfectant. The results indicate that additional microbial indicators are needed and suggest the potential use of FCM as a rapid monitoring tool for evaluation of microbial removal.

What Drives the Reuse of Municipal Wastewater? A County-Level Analysis of Florida

We analyze a unique dataset of county-level water reuse in Florida to determine whether water quality or scarcity concerns drive greater adoption of water reuse practices. Using dynamic panel data methods, we find that a county’s water reuse capacity is influenced by water quality conditions as well as water scarcity conditions, where scarcity is manifested as less frequent and more variable precipitation. However, our identification of the water quality effect is more robust to the choice of model specification compared to our water scarcity results. <i>(JEL Q25, Q53)</i>