Water Reuse Systems Research Articles

Design and implementation of closed-loop water reuse systems in urban and industrial settings for maximizing resource recovery and minimizing waste

Global demand for water while the freshwater sources are diminishing, it is necessary to find feasible solutions based on sustainable usage of resources. The goal is to provide beneficial use of as many resource constituents as possible with as little effluent discharge as possible leveraging innovations in treatment technologies and systems. Parameters of discussion include the operation and efficiency of membrane bioreactors, different kinds of oxidation, and reverse osmosis technologies. Such technologies are instrumental in improving the quality of water as well as enabling recovery of useful resources from the streams of wastewater that are normally obtained from several processes. This paper also assesses the feasibility of resource recovery closed-loop systems to measure its economic benefits determinable by operational expenses, energy usage and possible revenue streams from the recycled materials. Such knowledge synthesizes the findings of prior studies in the literature and emerging technologies that help to support this research and identify the impact that closed-loop water reuse systems can have. This emphasizes on the need to have proper regulatory status and consumer’s involvement for its general adoption and practicable implementation. In the long run, the integration of the systems explained above will definitely advance a sustainable water management system that will help in the stewardship of the environment and ensure that in case of arising challenges globally the country will be able to cope.

Development of modern irrigation systems for improving efficiency, reducing water consumption and increasing yields

The study was conducted to examine modern irrigation systems aimed at improving water efficiency, reducing water consumption and increasing crop yields. The study analysed the environmental and socio-economic aspects of modern irrigation systems, including their impact on the environment and social sustainability of agriculture. The study determined that the use of modern irrigation systems, such as drip irrigation and IoT-based automatic control systems, can significantly improve the efficiency of water use in agriculture. Data analysis demonstrated that such systems can reduce water consumption by up to 50% while increasing yields by up to 30%. The use of agricultural drones to monitor field conditions and precisely regulate irrigation helps to improve plant health and reduce labour costs. The study also determined that water recycling and reuse systems can significantly reduce the use of freshwater, which is especially important in regions with limited water resources. In general, modern irrigation technologies demonstrate high efficiency and economic feasibility, contributing to the sustainable development of agriculture. The study proved that the use of computer modelling and forecasting of plant water requirements provides optimal conditions for their growth, which further contributes to an increase in yields. The results of the study can be used in practice to develop and implement more efficient and environmentally friendly technologies in irrigation and drainage systems, which helps to reduce the negative impact on the environment through more efficient use of water resources and reduction of water runoff

Efficient recycling of sewage water in a polyester integrated industry: A case study

The water reuse system in a petrochemical and polyester integrated industry in Zhejiang, designed to handle industrial circular sewage, had a capacity of 1600 m3/h. The system employed a process comprising a high-efficiency sedimentation tank, V-shaped filter, aerated biological filter, ultrafiltration, and reverse osmosis. The high-efficiency sedimentation tank's mud water drainage, along with pretreatment through the biological aerated filter (BAF), V-shaped filter, and ultrafiltration system, resulted in an overall system recovery rate of 70 %. Actual operational results indicated removal rates exceeding 70 % for chemical oxygen demand (COD) and 94 % for chloride ions. The effluent water had a COD of ≤ 20 mg/L, chloride ion concentration of ≤ 50 mg/L, and conductivity of ≤ 20 μS/cm. Given the high recovery rate and the use of domestically produced ultrafiltration membranes, the direct operational cost of the system amounted to a mere 6.28 yuan/m3. This led to a reduction of approximately 9.67 million tons of wastewater discharged annually, fulfilling the objective of recycling industrial sewage for reuse.

Pilot scale demonstration of an underground biological aerated filter for rural wastewater treatment in a protected area

The availability of land is one of the advantages of rural wastewater treatment. However, this advantage may be absent in protected areas. The objective of this study is to showcase pilot-scale wastewater treatment approaches specifically tailored to address challenges presented by these unique circumstances. The demonstration case presented here involves a rural campsite where ground works are restricted. A pilot-scale decentralized system that includes a rainwater recycling system for potable water production (2–3 m3/d) and an underground biological aerated filter for wastewater treatment was installed. The biological aerated filter was built under a parking area (a so-called Phytoparking® system) and did as such not use additional ground surface. The Phytoparking with an area of 44 m2 was operated for 7 months and a total of 220 m3 grey water and 127 m3 black water was treated. Good pollutants removal efficiency was achieved for total suspended solids (93 %), COD (93 %), NH4+-N (93 %), TP (99 %), E.coli (log reduction 4.3) and total coliforms (log reduction 2.4). The potential wastewater reuse is not only about technological concern but also social acceptable concern. Therefore, the campsite customers' acceptance level of this system and the reused water were surveyed by a questionnaire. Based on the results of the study's pollutant removal efficiency and questionnaire responses, it can be concluded that local and/or decentralized water treatment and reuse systems were perceived positively.

Virus surrogates throughout a full-scale advanced water reuse system

Water reuse as an alternative water supply is increasing throughout the world due to water stress and scarcity; however, there are no standard practices for monitoring virus pathogens in such systems. This study aimed to identify suitable surrogates for virus fate, transport, and removal throughout a water reuse scheme. Various microbial targets (11 viruses, two phage, and three bacteria) were monitored using molecular and culture methods across all treatment stages in a wastewater reclamation facility and advanced water treatment facility. Criteria were established for identifying suitable surrogates, which included reliable detection, observable fate and transport, calculable log-reduction values (LRVs), correlations with other targets, and various morphological types. In total, five viruses (PMMoV, AiV, GII NoV, AdV, FRNA GII) met these stringent criteria and were suggested as potential virus surrogates. These surrogates enabled successful comparison of assigned versus actual LRVs throughout a water reuse scheme. Results suggest that virus pathogens are effectively removed throughout water reuse treatment and the suggested surrogates can be utilized for monitoring treatment performance and ensuring public health safety. This study provides a framework that water utilities across the world can reference for establishing virus monitoring practices.

Construction and Research of Water Reuse System in Green Intelligent Buildings

This paper discusses the construction and research of water reuse system in green intelligent buildings to improve the efficiency of water resources utilization and promote the sustainable development of the construction industry, which is of great significance for environmental protection and energy saving. In this paper, the design principles, technical parameters and costs of the water reuse system are considered comprehensively. The social and economic benefits are explored through empirical analysis of water reuse systems in different types of buildings. The COD concentration of treated water in the middle water is reduced to below 50mg/L, and the SS concentration is stabilized between 8 ∼ 10mg/L, which is in line with the standard. The actual scale of water production is significant, with an average daily treatment volume of 2548.8816m3 for the university water project, and 28.4478m3 and 431.625m3 for the residential neighborhood and public building, respectively. The average value of the whole life cycle cost prediction is about 39,767,335,000 yuan, and the payback period is 9 years. This study demonstrates the effectiveness and economic feasibility of the water reuse system for green intelligent buildings, which is important for improving water utilization efficiency and environmental sustainability in the construction industry.

To what extent do water reuse treatments reduce antibiotic resistance indicators? A comparison of two full-scale systems

Water reuse is an essential strategy for reducing water demand from conventional sources, alleviating water stress, and promoting sustainability, but understanding the effectiveness of associated treatment processes as barriers to the spread of antibiotic resistance is an important consideration to protecting human health. We comprehensively evaluated the reduction of antibiotic resistance genes (ARGs) and antibiotic-resistant bacteria (ARB) in two field-operational water reuse systems with distinct treatment trains, one producing water for indirect potable reuse (ozone/biologically-active carbon/granular activated carbon) and the other for non-potable reuse (denitrification-filtration/chlorination) using metagenomic sequencing and culture. Relative abundances of total ARGs/clinically-relevant ARGs and cultured ARB were reduced by several logs during primary and secondary stages of wastewater treatment, but to a lesser extent during the tertiary water reuse treatments. In particular, ozonation tended to enrich multi-drug ARGs. The effect of chlorination was facility-dependent, increasing the relative abundance of ARGs when following biologically-active carbon filters, but generally providing a benefit in reduced bacterial numbers and ecological and human health resistome risk scores. Relative abundances of total ARGs and resistome risk scores were lowest in aquifer samples, although resistant Escherichia coli and Klebsiella pneumoniae were occasionally detected in the monitoring well 3-days downgradient from injection, but not 6-months downgradient. Resistant E. coli and Pseudomonas aeruginosa were occasionally detected in the nonpotable reuse distribution system, along with increased levels of multidrug, sulfonamide, phenicol, and aminoglycoside ARGs. This study illuminates specific vulnerabilities of water reuse systems to persistence, selection, and growth of ARGs and ARB and emphasizes the role of multiple treatment barriers, including aquifers and distribution systems.

Effects of rearing system on growth responses and saltwater tolerance in spring Chinook Salmon (Oncorhynchus tshawytscha)

Pacific salmon (Oncorhynchus spp.) produced in United States conservation hatcheries are commonly reared in tanks and raceways supplied with single-pass water. As controlled studies comparing water reuse vs. traditional single-pass aquaculture systems are limited, we conducted a 20-week growth trial followed by a one-week saltwater challenge to compare growth, survival and saltwater tolerance of juvenile spring Chinook salmon (O. tshawytscha, 5.2 g initial weight) reared in single-pass rectangular tanks (hereafter rectangular tanks), single-pass circular tanks (hereafter circular tanks), or in circular tanks of recirculating aquaculture systems (RAS, 3% constant makeup water on a flow basis) or partial recirculating aquaculture systems (PRAS, 20% constant makeup water on a flow basis). Water volume provided to rearing tanks did not differ among systems, but water velocities in the circular tanks and in the RAS and PRAS fish culture tanks were higher than in the rectangular tanks. Dissolved oxygen levels declined throughout the study in all systems and were significantly lower in RAS than in the single-pass systems. By week 16, ammonia levels were significantly reduced while nitrite‑nitrogen (NO2-N) and nitrate‑nitrogen (NO3-N) levels were significantly elevated in RAS compared with single-pass systems.Salmon grown in rectangular tanks exhibited significantly lower weight gain and feed efficiency (FE; g gain/g feed) compared with fish reared in the other systems. Survival of salmon grown in the rectangular tanks (99.1%) also was significantly lower than that of fish reared in circular tanks (100%) or PRAS (100%), but was not different from that of fish reared in RAS (99.8%). Survival during the saltwater challenge was significantly reduced in salmon that were reared during the growth trial in rectangular tanks (70%) compared with that of fish that were reared in the other systems (92–96%). Results of this study suggest lower growth and survival of salmon reared in rectangular tanks may be related to reduced water velocity and that RAS and PRAS may be appropriate for rearing spring Chinook salmon for conservation purposes.

Water reuse from wastewater: Experiences and challenges of implementing a full-scale water reuse system in a food industry plant

This paper presents experiences and challenges related to the implementation and successful 3-year operation of a full-scale station for water reuse from wastewater in one of the largest poultry slaughterhouses in Europe. Solved problems for implementing deammonification, as well as automatic coagulant dosing for wastewater pre-treatment, improvement of activated sludge separation, and digestate management, are presented and discussed. Two major limitations of stable water reclamation were a limit of 30 mg N/L in the effluent to the river and the passing of cationic flocculants and natural polymers formed by activated sludge microorganisms to the ultrafiltration units. The limit of 30 mg N/L was achieved by implementing i) a unique deammonification system to treat leachate from the anaerobic digester, ii) automatic coagulant dosing to mitigate high nitrogen peaks and balance organic compounds between biogas production and efficient denitrification. Flocculants and polymers passing to the ultrafiltration units and causing a sharp drop in water recovery were eliminated by stabilizing the zeta potential of the sludge, adding an antiscalant before the ultrafiltration, and automatic control of wastewater coagulation at primary treatment, responding to COD peaks. With improvements described in the article, the water reuse system provides a stable supply of 4000 m3/d of high-quality water, resulting in over 4 million m3 of water reclaimed since 2020.

Ensuring microbial water quality for on-site water reuse: Importance of online sensors for reliable operation

A growing number of cities and regions are promoting or mandating on-site treatment and reuse of wastewater, which has resulted in the implementation of several thousand on-site water reuse systems on a global scale. However, there is only limited information on the (microbial) water quality from implemented systems. The focus of this study was on two best-in-class on-site water reuse systems in Bengaluru, India, which typically met the local water quality requirements during monthly compliance testing. This study aimed to (i) assess the microbial quality of the reclaimed water at a high temporal resolution (daily or every 15 min), and (ii) explore whether measurements from commercially available sensors can be used to improve the operation of such systems. The monitoring campaign revealed high variations in microbial water quality, even in these best-in-class systems, rendering the water inadequate for the intended reuse applications (toilet flushing and landscape irrigation). These variations were attributed to two key factors: (1) the low frequency of chlorination, and (2) fluctuations of the chlorine demand of the water, in particular of ammonium concentrations. Such fluctuations are likely inherent to on-site systems, which rely on a low level of process control. The monitoring campaign showed that the microbial water quality was most closely related to oxidation–reduction potential (ORP) and free chlorine sensors. Due to its relatively low cost and low need for maintenance, the ORP emerges as a compelling candidate for automating the chlorination to effectively manage variations in chlorine demand and ensure safe water reuse. Overall, this study underscores the necessity of integrating treatment trains, operation, and monitoring for safe on-site water reuse.

Financial analysis of decentralized water reuse systems in mission critical facilities at U.S. Army installations

Decentralized water reuse is a financially viable fit-for-purpose approach for water sustainment in mission critical facilities.

Efficient Water Use in Dairy Cattle Production: A Review

Background: Dairy cattle production has often been pointed out as a big source of wastewater; although these statements seem exaggerated, they can save a lot of water when a correct use of this resource is made. Objective: The objective of this review was to explore what technological improvements in drinking and feeding systems, water reuse systems, and irrigation systems have been made in the last ten years that allow a more efficient use of water and consequently a decrease in water use in dairy cattle production. Methods: The literature analysis for the review involved a keyword-based search, mainly for conference and/or journal articles. The scientific research databases, ScienceDirect and IEEE Xplore, as well as the scientific search engine Google Scholar, were employed to conduct this review. Results: Dairy farmers can reduce their water footprint by implementing practices that can include proper feeding of animals and monitoring of water consumption, adequate ventilation of facilities, as well as maintenance and repair of water, wastewater, and irrigation systems. Water from heat exchange systems to cool milk after milking can be reused to water and irrigate fields, and the farmers can also use technological equipment to increase the efficiency of irrigation. Conclusion: Proper management strategies are highly essential for sustaining the livestock production systems and meeting the food demands of a growing population with the available water resources, for which water-saving technologies and strategies are the need of the hour. The use of technological options has been a key driving force for the transition to smarter farming systems and for efficient water use in dairy farms.

Barriers and Drivers to Adoption of Water Reuse In Buildings: A Sociotechnical Analysis in Ceará, Brazil

Purpose: This study aims to identify the barriers and drivers towards the adoption of water reuse systems in buildings in regions with water scarcity, such as the Brazilian Northeast. Method: A qualitative study was carried out in the state of Ceará, Brazil. The study encompassed the analysis of content from seventeen in-depth interviews and documentary evidence. Results and conclusion: The primary adoption drivers were found to be economic savings through consumption reduction and environmental awareness. Main barriers included the initial investment and payback time, as well as user practices, such as residents' lack of system maintenance. In addition, political and institutional aspects, such as the absence of fiscal incentives, also played a key role. In conclusion, water reuse in buildings constitutes an innovation that requires further development to promote significant adjustments of the socio-technical regime. Originality/value: This research introduces innovation by conducting an analysis of the adoption of water reuse in buildings based on the multi-level perspective of socio-technical transitions towards sustainability. It focuses on a state in the Brazilian Northeast, whose territory is primarily situated in the Caatinga biome, characterized by a semi-arid climate and a history of severe drought cycles. Research implications: The results provide valuable insights for researchers, technology developers, and policymakers to develop actions that stimulate the implementation and diffusion of water reuse in buildings.

Water and Sanitation Services at the Local Government Level in Bangladesh: An Analysis of SDG 6 Implementation Status and Way Forward

This study looks into the state of SDG 6 implementation at the local government level in Rajshahi City Corporation (RCC) with a focus on water and sanitation services. The research adopts a mixed-method approach and in-depth interviews to collect primary data. The study analyses the collected data using both quantitative and qualitative techniques. It has been found that large numbers of people do not always have access to enough water, demonstrating the problem of water scarcity in the region. According to the study, only a small percentage of participants tested their drinking water, which suggests that participants were not aware of the importance of water quality. Additionally, the lack of personal water purification and reuse systems is revealed by the research, indicating a gap in sustainable water management practices. Most of the city dwellers expressed dissatisfaction with the authority’s management of the water supply, indicating insufficient oversight and governance. The findings highlight the need for improved infrastructures, water treatment techniques, education campaigns, and governance mechanisms to effectively meet SDG 6 targets and guarantee residents of RCC access to clean water and sanitary facilities.

Modeling and optimization of synergistic ozone-ultraviolet-chlorine process for reclaimed water disinfection: From laboratory tests to software simulation.

The ozone-ultraviolet (UV)-chlorine process is a highly effective method of disinfection in water reuse system, but currently still lacks precise quantification and accurate control. It is difficult to determine the dosage of each disinfectant because of the complex interactions that occur between disinfection units and the complicated mathematical calculation required. In this study, we proposed a dosage optimization model for ozone-UV-chlorine synergistic disinfection process. The model was able to identify the cost-effective doses of the disinfectants under the constraints of microbial inactivation, decolorization, and residual chlorine retention requirements. Specifically, the simulation of microbial inactivation rates during synergistic disinfection process was accomplished through quantification of the synergistic effects between disinfection units and the introduction of enhancement coefficients. In order to solve this optimization model rapidly and automatically, a MATLAB-based software program with graphical user interface was developed. This software consisted of calibration unit, prediction unit, assessment unit, and optimization unit, and was able to simulate synergistic ozone-UV-chlorine process and identify the optimal dose of ozone, UV, and chlorine. Validation experiments revealed good agreements between the experimental data and the results calculated by the developed software. The developed software is believed to help the water reclamation plants improve disinfection efficiency and reduce the operational costs of synergistic disinfection processes.

Enhancing Water Safety in Decentralized Water Reuse Systems With Low-Cost Prussian Blue Amperometric Sensors for Free Chlorine Monitoring

Enhancing Water Safety in Decentralized Water Reuse Systems With Low-Cost Prussian Blue Amperometric Sensors for Free Chlorine Monitoring

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).

Predicting microbial water quality in on-site water reuse systems with online sensors

Widespread implementation of on-site water reuse is hindered by the limited availability of monitoring approaches that ensure microbial quality during operation. In this study, we developed a methodology for monitoring microbial water quality in on-site water reuse systems using inexpensive and commercially available online sensors. An extensive dataset containing sensor and microbial water quality data for six of the most critical types of disruptions in membrane bioreactors with chlorination was collected. We then tested the ability of three typological machine learning algorithms – logistic regression, support-vector machine, and random forest – to predict the microbial water quality as “safe” or “unsafe” for reuse. The main criteria for model optimization was to ensure a low false positive rate (FPR) – the percentage of safe predictions when the actual condition is unsafe – which is essential to protect users health. This resulted in enforcing a fixed FPR ≤ 2%. Maximizing the true positive rate (TPR) – the percentage of safe predictions when the actual condition is safe – was given second priority. Our results show that logistic-regression-based models using only two out of the six sensors (free chlorine and oxidation–reduction potential) achieved the highest TPR. Including sensor slopes as engineered features allowed to reach similar TPRs using only one sensor instead of two. Analysis of the occurrence of false predictions showed that these were mostly early alarms, a characteristic that could be regarded as an asset in alarm management. In conclusion, the simplest algorithm in combination with only one or two sensors performed best at predicting the microbial water quality. This result provides useful insights for water quality modeling or for applications where small datasets are a common challenge and a general advantage might be gained by using simpler models that reduce the risk of overfitting, allow better interpretability, and require less computational power.

Conceptualizing Equity for Onsite Nonpotable Water Reuse Systems in the United States

There has been a push to adopt onsite nonpotable water reuse systems (ONWS) as a supplement for conventional centralized water infrastructure. While a majority of work has centered on developing the technology, we instead focus on the implications for equity when attempting wide-scale adoption. Using existing definitions and resources for water equity in the sector, we investigate ONWS in San Francisco and New York City, using semi-structured interviews conducted with stakeholders. A qualitative approach with thematic coding and sentiment analysis is used to explore how stakeholders perceive equity in relation to their work and the resulting social, economic, and environmental implications for ONWS. Results confirm a general sentiment—equity is necessary, yet it is unclear how to incorporate this concept into practice. In some instances, equity is viewed as secondary to utility planning, operation, and management; we propose that it should be incorporated intentionally as an approach to enhance service provision. This study has implications for literature and practice as it demonstrates how decision-makers in ONWS programs engage with the concept of equity. We demonstrate how stakeholders’ roles can impact their implementation of equity, and discuss how practitioners may use this work as foundational understanding in assessing internal operations and practices, improving infrastructure in the pathway to sustainable development.

Development of a Multi-Objective Optimal Design Approach for Combined Water Systems

Recently, due to extreme climate change, damage from flooding has been increasing; however, water shortages are being announced simultaneously. Moreover, the water distribution system’s ability to supply consumers is being overwhelmed because of urbanization, population concentration, and increases in water consumption. For this reason, to solve the water shortage problem, water reuse technologies are developing and improving that perform simple chemical treatment processes to reuse water for flushing toilets, washing, gardening, etc. but not as drinking water. However, most water reuse systems are designed and operated as independent systems, such as reusing water used in individual buildings or using rainwater. Therefore, this study develops an optimal design for the combined water systems, which is modeling and designing water distribution systems, urban drainage systems, and water reuse systems simultaneously to solve the water shortage and reduce flooding damage. To consider the combined water systems design, the existing water distribution system (WDS) demand is divided into drinking water and other uses, and the resource of other water is assumed by the rainwater storage tank for covering the amount of exceeding precipitation. To derive optimal design solutions for the combined three water systems, single- and multi-objective optimization techniques are applied considering various design criteria (i.e., construction cost, system resilience, and flooding volume on the exceeding design rainfall intensity). The developed combining water system design techniques could be used to create designs that solve the problems of medium and long-term water shortages and sustainable water systems development.