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Abstract: Climate change and the increase of population pose challenges to ensuring suitable water supply in water-scarce regions. This work presents a comparative analysis of the water-supply approaches adopted in Los Angeles, Southeastern Spain, and Sydney. Results show a decrease in per-capita water use in the period 2000–2020, which reflects an improvement in water conservation. Social factors in the domain of hydropolitics and economic efficiency explain the divergence of water policies adopted. The adaptation to water scarcity and growing population in three regions of developed countries located in different continents sheds light on challenges facing the achievement of water security worldwide.

Due to changes that have occurred in ecological conditions, the requirement to use wastewater has been considered more seriously in the agricultural sector, because agriculture is the source of human nutrition, health and security. Based on this, the purpose of this research was to systematically analysis the components affecting sustainable management of wastewater use (SMWWU) in the viewpoint of critical theory paradigm. Inductive qualitative content analysis (IQCA) was used for systematic analysis. In this regard, the software used was MAXQDA. The statistical population included valid scientific articles and knowledgeable experts in wastewater management in the agricultural sector in Tehran province, Iran. The sampling method for articles was by searching based on keywords and for experts by purposeful method until theoretical saturation was reached. The results of IQCA in the form of a model showed that the six main components "economic," "environmental," "contextual," "individual," "management and planning" and "education and extension" affect SMWWU. Each of these components also includes several factors and variables that can strengthen SMWWU and reduce the water crisis by paying attention to them. The obtained model can be used by policy makers and interested parties in making decisions and planning water protection measures. [ABSTRACT FROM AUTHOR]

Tailwater-based hydroponic vegetable is a promising strategy for domestic wastewater recycling. However, the effect of residual antibiotics on the hydroponic vegetable system and the relation between hydroponic culture parameters and the residual water quality are still unclear. Here, the typical antibiotic Levofloxacin (LVFX) was employed, and the effect of LVFX (5 mg/L) on the residual water quality, plant growth and microbial community of water spinach hydroponic culture system were investigated under different hydraulic residence times (HRT). Obvious toxic effects on water spinach were observed, and the highest removal rate of LVFX (about 6 %) and TN (25.67±1.43 %) was observed when HRT was 7 days. Hydroponic culture increased the microbial abundance, diversity, and microbial community stability. To optimize the hydroponic culture, actual sewage plant tailwater spiked with 20 μg/L LVFX, along with three common planting substrates (sponge, ceramsite, and activated carbon) were used for the hydroponic culture of lettuce (seasonal reasons). The inhibition effect of LVFX on the removal of NO3--N and TN was observed even as the LVFX concentration decreased significantly (from 14.62 ± 0.44 μg/L to 0.65 ± 0.07 μg/L). The best growth situation of lettuce and removal rates of NH4+-N, NO3--N, TN, especially LVFX (up to 95.65 ± 0.54 %) were observed in the activated carbon treated group. The overall results indicate the negative effect of residual antibiotics on the hydroponic vegetable systems, and adding activated carbon as substrate is an effective strategy for supporting plant growth and controlling discharged risk.

In closed-loop soilless culture systems, the increase of the electrical conductivity (EC) caused by Na+ accumulation is a major bottleneck for recycling of the nutrient solution if water sources are used which contain Na+ at substantial concentrations. Currently, the recommended nutrient concentrations for the root zone of tomato exceed those for maximising yield, aiming to induce a moderate salinity stress to enhance fruit quality. A new strategy for Na+ accumulation management is proposed, which gradually reduces the target concentrations of macronutrients except for P in the root zone in proportion to the accumulation of Na+, considering a minimum safety threshold, while maintaining the mutual ratios between them constant. The algorithm developed to support this new strategy was applied via the Decision Support System NUTRISENSE (https://nutrisense.online/) in tomato grown in mineral wool in a closed-loop soilless cropping system. The new strategy was compared with the standard strategy of maintaining constant nutrient concentrations in the root zone. The results demonstrate the efficiency of the new strategy to control the EC in the root zone while ensuring a balanced nutrition of the plants. By applying this strategy, the losses of nitrate and phosphorus due to discharge of drainage solution (DS) were reduced by 25.5 % and 9.20 %, respectively, while avoiding yield losses due to salinity stress, and increasing water productivity (WP) and agronomic efficiency of nitrogen (AEN). Nevertheless, the new strategy could not fully eliminate the need to discharge DS when raw water with a Na+concentration of 4 mM was used to prepare nutrient solution.

The mining industry is confronted with substantial challenges in achieving environmental sustainability, particularly regarding water usage, waste management, and dam safety. The increasing global demand for minerals has led to increased mining activities, resulting in significant environmental consequences. By 2025, an estimated 19 billion tons of solid tailings are projected to accumulate worldwide, exacerbating concerns over their management. Tailings storage facilities represent the largest water sinks within mining operations. The mismanagement of water content in tailings can compromise their stability, leading to potential dam failures and environmental catastrophes. In response to these pressing challenges, the mining industry is increasingly turning to innovative solutions such as tailings dewatering and water reuse/recycling strategies to promote sustainable development. This review paper aims to (I) redefine the role of mine tailings and explore their physical, chemical, and mineralogical characteristics; (II) discuss environmental concerns associated with conventional disposal methods; (III) explore recent advancements in dewatering techniques, assessing their potential for water recovery, technical and economic constraints, and sustainability considerations; (IV) and present challenges encountered in water treatment and recycling within the mining industry, highlighting areas for future research and potential obstacles in maximizing the value of mine tailings while minimizing their environmental impact. [ABSTRACT FROM AUTHOR]

One of the most important methods of optimising water consumption is grey water recycling. From a technological point of view, the treatment of grey water guarantees that it can be reused for domestic or corporate purposes, but it raises the issue of the social acceptance of the use of such water. This study aimed to assess the possibility of using grey water in households in Poland. The originality of this research study lies in the application of the PROFIT method for the separate construction of models of the benefits of grey water according to user groups. Four groups were identified, differentiated by gender and age; age and possession of an irretrievable water meter; gender and place of residence; place of residence and possession of an irretrievable water meter. To answer the formulated research questions, a diagnostic survey method was used, in which 807 randomly selected respondents from all over Poland were surveyed. The results of the survey indicate that homeowners perceive the potential use of grey water as beneficial, pointing most often to the following factors: rebuilding groundwater levels, reduced extraction of drinking water from rivers and other water bodies, and increased vegetation growth. On the other hand, they are concerned about the need to reconstruct the existing water and sewerage systems in order to produce drinking water from grey water as well as about the high cost and parameter stability of drinking water produced from grey water. Furthermore, men and older people attribute less importance to measures related to the introduction of good practices based on the reuse of recycled water in water management. Women, on the other hand, appreciate almost all opportunities to use grey water to a greater extent than men. [ABSTRACT FROM AUTHOR]

Due to changes that have occurred in ecological conditions, the requirement to use wastewater has been considered more seriously in the agricultural sector, because agriculture is the source of human nutrition, health and security. Based on this, the purpose of this research was to systematically analysis the components affecting sustainable management of wastewater use (SMWWU) in the viewpoint of critical theory paradigm. Inductive qualitative content analysis (IQCA) was used for systematic analysis. In this regard, the software used was MAXQDA. The statistical population included valid scientific articles and knowledgeable experts in wastewater management in the agricultural sector in Tehran province, Iran. The sampling method for articles was by searching based on keywords and for experts by purposeful method until theoretical saturation was reached. The results of IQCA in the form of a model showed that the six main components “economic,” “environmental,” “contextual,” “individual,” “management and planning” and “education and extension” affect SMWWU. Each of these components also includes several factors and variables that can strengthen SMWWU and reduce the water crisis by paying attention to them. The obtained model can be used by policy makers and interested parties in making decisions and planning water protection measures.

Inappropriate fertilisation results in the pollution of groundwater with nitrates and phosphates, eutrophication in surface water, emission of greenhouse gasses, and unwanted N deposition in natural environments, thereby harming the whole ecosystem. In greenhouses, the cultivation in closed-loop soilless culture systems (CLSs) allows for the collection and recycling of the drainage solution, thus minimising contamination of water resources by nutrient emissions originating from the fertigation effluents. Recycling of the DS represents an ecologically sound technology as it can reduce water consumption by 20–35% and fertiliser use by 40–50% in greenhouse crops, while minimising or even eliminating losses of nutrients, thereby preventing environmental pollution by NO3− and P. The nutrient supply in CLSs is largely based on the anticipated ratio between the mass of a nutrient absorbed by the crop and the volume of water, expressed as mmol L−1, commonly referenced to as "uptake concentration" (UC). However, although the UCs exhibit stability over time under optimal climatic conditions, some deviations at different locations and different cropping stages can occur, leading to the accumulation or depletion of nutrients in the root zone. Although these may be small in the short term, they can reach harmful levels when summed up over longer periods, resulting in serious nutrient imbalances and crop damage. To prevent large nutrient imbalances in the root zone, the composition of the supplied nutrient solution must be frequently readjusted, taking into consideration the current nutrient status in the root zone of the crop. The standard practice to estimate the current nutrient status in the root zone is to regularly collect samples of drainage solution and determine the nutrient concentrations through chemical analyses. However, as results from a chemical laboratory are available several days after sample selection, there is currently intensive research activity aiming to develop ion-selective electrodes (ISEs) for online measurement of the DS composition in real-time. Furthermore, innovative decision support systems (DSSs) fed with the analytical results transmitted either offline or online can substantially contribute to timely and appropriate readjustments of the nutrient supply using as feedback information the current nutrient status in the root zone. The purpose of the present paper is to review the currently applied technologies for nutrient and water recycling in CLSs, as well as the new trends based on ISEs and novel DSSs. Furthermore, a specialised DSS named NUTRISENSE, which can contribute to more efficient management of nutrient supply and salt accumulation in closed-loop soilless cultivations, is presented. [ABSTRACT FROM AUTHOR]

In the 1950s, V-2 reservoir (Lake Kyzyl-Tash) was used for cooling industrial uranium–graphite reactors (IUGRs). When water passed through the IUGR core, activation radionuclides (ARs) were produced by nuclear reactions of reactor neutrons with nuclei of chemical elements present in water and were accumulated in water. The AR activity concentration in water from V-2 reservoir depends on the concentration of chemical elements in the reservoir. Data on the content of 16 elements in V-2 water in the period 1948–1956 were collected. These data were analyzed taking into account the characteristic natural abundance of elements in water of the Irtyash–Kasli lake system and the additional technogenic pollution of the reservoir in the course of its operation. The main source of AR transfer from V-2 reservoir to the Techa River was controlled water discharge through open shutters of the P-2 dam (or uncontrolled water seepage through closed shutters). A mathematical model was suggested, and the activity concentrations in V-2 water were calculated for 16 elements and 31 nuclear reactions yielding 20 ARs. The model was verified using the archive data on the activity concentrations of 32Р in V-2 water in 1953–1956. All the calculation results well agree with the available experimental data. The source term for AR transfer from V-2 reservoir to the Techa River in relation to the water flow rate through P-2 dam was determined. The experimental data on the scale of the distribution of the 32Р activity concentration along the Techa River were analyzed. The results obtained allow taking into account the AR contribution to the total radioactive pollution of the river and evaluating the possible radiation impact on the population and biota. [ABSTRACT FROM AUTHOR]

Water reuse with Advanced Water Treatment (AWT) is increasingly appealing for urban areas seeking water supply reliability. In cities facing water scarcity, how can large-scale reuse support reliability and how do reuse operations affect water quality, energy use, and water conservation? This paper presents a systems analysis of metropolitan-scale water reuse and its effects on water supply and quality. For the case study of Los Angeles County, California, USA, hydroeconomic modeling is used to evaluate reuse as a contributor to water supply given urban water conservation, drought-induced water scarcity, and costs and benefits for supply and demand. Results indicate that AWT can be a viable source of supply especially when coupled with conservation. Across modeled scenarios, reuse provides as much as 30% of regional supplies. New water reuse with AWT becomes viable when imported water availability is 50% or less of historic values. Existing indirect potable reuse operations in the county remain important. Systemwide energy intensity of operations increases with greater reuse in the absence of water conservation. Modeled influent flow rates to wastewater treatment plants resemble historical values, but extreme flow events could pose risks. The paper offers a holistic framework to evaluate water reuse as a component of urban water management. [ABSTRACT FROM AUTHOR]

This research aimed at treating condensate wastewater from the by-product of production processes in the canned tuna factories for recycling into fish oil production by reducing pH and deodorization using activated carbon, Eunicarb ID 900. The research began with batch adsorption to study the effect of pH 7-9 on the chemical oxygen demand (COD) removal (parameters representing odor) followed by continuous adsorption at the production plant using 15 cm diameter and 150 cm height adsorber. The result showed that a faster initial adsorption rate was achieved at lower pH while higher equilibrium COD removal was obtained at higher pH with the highest 90% COD removal. The adsorption was fitted well with Pseudo-second-order kinetic and Freundlich's isotherm. It was found that this treatment could not only removed the odor but also produced higher water quality which meets the limitation of water for fish oil extraction manufacturing. Subsequently this research suggested a six-month operation cycle based on the result operated at an actual condensate production rate of 2.5 m3/h. No effect in both quantitative and qualitative quality of fish oil was observed after processing with the treated condensate. The economic assessment for the existing plant evaluates a payback period of 2.86 y, reveals it is readiness to be adopted for the factory. [ABSTRACT FROM AUTHOR]

The objective of this research was to recover protein and water from tuna defrosting wastewater. Tuna defrosting wastewater (TDW) was concentrated, and salt protein residue (PR) was separated from concentrate TDW (cTDW). Protein in the cTDW was precipitated (PP). Salt was removed from PR and PP by using hot water (60 °C). PR and PP were dried at 50 °C before analysis for total protein, amino acid profile and salt content. Salty protein solution (PS) following salt removal from the precipitate was collected and concentrated. Then salt cPS was desalted by Sephadex G-25, and the elution was collected and concentrated. The resulting cPS was analyzed for pH, total protein, salt content, amino acid profile and antioxidant properties. Water from the protein recovery procedure was collected and analyzed for biological qualities (heterotrophic plate count, coliform bacteria, E. coli, Staphylococcus aureus, Salmonella spp. and Clostridium perfringens), physical qualities (apparent color, turbidity, pH) and chemical qualities (total dissolved solids, total hardness and sulfate).The results showed that cTDW contained 11.57 ± 0.03 % protein and 3.36 ± 0.03% NaCl. After salt was removed, the dried PR and PP contained 33.10 ± 0.16% and 6.92 ± 0.13% protein, respectively, and 0.23 ± 0.00% and 0.05 ± 0.00% NaCl, respectively. Dried PR contained 9 essential amino acids at higher concentrations than in PP. Concentrated PS contained 3.15 ± 0.12% protein and no NaCl. Histidine (254.15 mg/100 g) was the dominant amino acid in cPS. Antioxidant properties are shown by values for DPPH, ABTS and FRAP. The physical, chemical and bacterial parameters of recovered water met the guidelines for drinking water quality. These results indicate that recovery of protein and water is possible in fish processing, which could reduce costs for processors and benefit the environment.

Microalgae biotechnology is hampered by the high production costs and the massive usage of water during large-volume cultivations. These drawbacks can be softened by the production of high-value compounds and by adopting metabolic engineering strategies to improve their performances and productivity. Today, the most sustainable approach is the exploitation of industrial wastewaters for microalgae cultivation, which couples valuable biomass production with water resource recovery. Among the food processing sectors, the dairy industry generates the largest volume of wastewaters through the manufacturing process. These effluents are typically rich in dissolved organic matter and nutrients, which make it a challenging and expensive waste stream for companies to manage. Nevertheless, these rich wastewaters represent an appealing resource for microalgal biotechnology. In this study, we propose a sustainable approach for high-value compound production from dairy wastewaters through cyanobacteria. This strategy is based on a metabolically engineered strain of the model cyanobacterium Synechococcus elongatus PCC 7942 (already published elsewhere) for 2-phenylethanol (2-PE). 2-PE is a high-value aromatic compound that is widely employed as a fragrance in the food and cosmetics industry thanks to its pleasant floral scent. First, we qualitatively assessed the impact of four dairy effluents on cyanobacterial growth to identify the most promising substrates. Both tank-washing water and the liquid effluent of exhausted sludge resulted as suitable nutrient sources. Thus, we created an ideal buffer system by combining the two wastewaters while simultaneously providing balanced nutrition and completely avoiding the need for fresh water. The combination of 75% liquid effluent of exhausted sludge and 25% tank-washing water with a fine-tuning ammonium supplementation yielded 180 mg L−1 of 2-PE and a biomass concentration of 0.6 gDW L-1 within 10 days. The mixture of 90% exhausted sludge and 10% washing water produced the highest yield of 2-PE (205 mg L−1) and biomass accumulation (0.7 gDW L−1), although in 16 days. Through these treatments, the phosphates were completely consumed, and nitrogen was removed in a range of 74%–77%. Overall, our approach significantly valorized water recycling and the exploitation of valuable wastewaters to circularly produce marketable compounds via microalgae biotechnology, laying a promising groundwork for subsequent implementation and scale-up.

Abstract Water is limited and is unevenly distributed globally. India being home to approximately 18% of the global population accounts for only 4% of global renewable water resources, making it the world’s 13th most water-stressed country. The increase in human population coupled with accelerated economic activities and climate change has put enormous pressure on government and policymakers in India to find different innovative and smart ways to manage the demand–supply gap in the water sector. Despite having the largest water infrastructure in the world and concerns raised about increasing water crisis in national discourse at academic, policy and governance levels, the tangible outcome does not resonate adequately on the ground level. Identification of alternate tools, calibration and fine-tuning relevant policy and planning necessitate the need of implementing water auditing and water recycling to meet the ever-increasing water demand as far as the water footprint in India is concerned. Based on the principle of what gets measured gets managed, water auditing best caters to the water management needs and is yet to become a top priority to curb the water crisis. Public acceptance seems to be one of the major barriers in universalizing water recycling in India which is aggravated by the uneven and/or absence of a proper and adequate water governance approach and structure. This paper tries to highlight the major challenges water resources management is facing in India and aims to illustrate how well planned water auditing and water recycling as a tool can deliver in effective and rational utilization and distribution of water.

Water pollution occurs due to the discharge of domestic waste mixed with residential, industrial, commercial, and agricultural wastewater. Conventional water treatment methods using aerobic/anaerobic methods can cause problems with the production of high green gases and result in the greenhouse effect. Microbial-based domestic sewage treatment technology using polyvinyl alcohol biofilm supporting media was introduced as an alternative measure to overcome this problem. The objective of the study was to determine the performance of polyvinyl alcohol beads in polishing domestic wastewater. In this study, the bacterium Bacillus velezensis isolate JB7 was used together with PVA as a raw material to treat domestic sewage wastewater more efficiently and stably. The results of the study show the effectiveness of domestic wastewater treatment in several factors such as pH value, chemical oxygen demand (COD), phosphorus, nitrate, nitrite, ammonia, and total suspended solids. In conclusion, domestic wastewater treatment methods using polyvinyl alcohol beads are seen to be effective, reducing the use of sewage waste plant construction sites and able to avoid the use of non-recyclable materials such as plastics and synthetics.

Interest in wastewater recycling as an alternative source has grown as a result of increased water demand, water shortage due to population increase, low rainfall, and economic and environmental issues. Water recycling from greywater can serve as a sustainable solution for water demands. Nowadays, membrane bioreactor systems have significantly improved treatment performance and have been widely used in water reuse and reclamation. However, optimization of the MBR system in greywater treatment has received less attention. In this context, an experimental investigation of the MBR for greywater reuse was considered to identify the optimal hydraulic retention time of the MBR system. The lab-scale MBR consisted of a bioreactor with a net volume of 10 L, containing one submerged polypropylene hollow fiber membrane module with an area of 0.2 m2. The lab-scale MBR was fed with greywater collected from a dormitory of Shiraz University and operated for 160 days. Four HRTs (3, 5, 7 and 9 h) were tested to investigate the performance of the MBR system on the removal of total ammonia nitrogen, organic matter, turbidity, and total suspended solid. The results showed that the MBR system could remove more than 95% of COD, 99.5% of BOD5, 99% TAN, and 99.2% of TSS from greywater. The COD, BOD5, TSS effluents, and turbidity were below 10.5 mg/L, 0.4 mg/L, 0.6 mg/L, and 0.3 NTU, respectively. The results also showed that the optimal HRT of the MBR system for greywater treatment was 3 h. In conclusion, the MBR system with optimal HRT of 3 h is highly efficient for greywater treatment and it could produce sustainable water for non-potable reuse such as toilet flushing reuse in terms of chemical–physical quality parameters.

Mismanagement of existing water supplies is threatening the sustainability of these resources, resulting in the degradation of source water quality and decreasing water supplies. Notably, substantial amounts of source water are withdrawn and treated for industrial use, irrigation, thermoelectric power, and mining purposes; only a small portion is allocated for municipal and domestic purposes. The increasing incidence of extreme weather events further accentuates both water quality and quantity concerns, stressing the need for increased efficiency to improve water supply sustainability. To that end, substituting source water with recycled water can help improve water supply sustainability in many places across the United States and the rest of the world. In this article, we focus on the case of Joliet, a town in Illinois where the supporting aquifer verges on the point of nonviability. To assist Joliet, Chicago's City Council approved a plan for the Chicago Department of Water Management to reallocate Lake Michigan drinking water from the Chicago basin to Joliet. In this study, we evaluate the environmental sustainability of four possible scenarios: 1.) proposed water-use cycle from the water treatment process, with delivery to all users, 2.) supplying recycled water to industries and other potential non-potable uses without additional treatment, 3.) supplying recycled water treated with additional disinfection to industrial and other non-potable uses, and 4.) supplying recycled water from an alternative water reclamation plant with an existing disinfection unit. We perform a life cycle assessment to compare the environmental impacts in each scenario. Findings of the study show that treated wastewater in industrial applications would significantly reduce environmental emissions compared to the proposed no-reuse scenario. The results suggest that water reuse can help save energy, reduce potable water consumption, generate revenue, and reduce the environmental load on water bodies. [ABSTRACT FROM AUTHOR]

Water is limited and is unevenly distributed globally. India being home to approximately 18% of the global population accounts for only 4% of global renewable water resources, making it the world's 13th most water-stressed country. The increase in human population coupled with accelerated economic activities and climate change has put enormous pressure on government and policymakers in India to find different innovative and smart ways to manage the demand–supply gap in the water sector. Despite having the largest water infrastructure in the world and concerns raised about increasing water crisis in national discourse at academic, policy and governance levels, the tangible outcome does not resonate adequately on the ground level. Identification of alternate tools, calibration and fine-tuning relevant policy and planning necessitate the need of implementing water auditing and water recycling to meet the ever-increasing water demand as far as the water footprint in India is concerned. Based on the principle of what gets measured gets managed, water auditing best caters to the water management needs and is yet to become a top priority to curb the water crisis. Public acceptance seems to be one of the major barriers in universalizing water recycling in India which is aggravated by the uneven and/or absence of a proper and adequate water governance approach and structure. This paper tries to highlight the major challenges water resources management is facing in India and aims to illustrate how well planned water auditing and water recycling as a tool can deliver in effective and rational utilization and distribution of water. [ABSTRACT FROM AUTHOR]

Water pollution occurs due to the discharge of domestic waste mixed with residential, industrial, commercial, and agricultural wastewater. Conventional water treatment methods using aerobic/anaerobic methods can cause problems with the production of high green gases and result in the greenhouse effect. Microbial-based domestic sewage treatment technology using polyvinyl alcohol biofilm supporting media was introduced as an alternative measure to overcome this problem. The objective of the study was to determine the performance of polyvinyl alcohol beads in polishing domestic wastewater. In this study, the bacterium Bacillus velezensis isolate JB7 was used together with PVA as a raw material to treat domestic sewage wastewater more efficiently and stably. The results of the study show the effectiveness of domestic wastewater treatment in several factors such as pH value, chemical oxygen demand, phosphorus, nitrate, nitrite, ammonia, and total suspended solids. As conclusion, domestic wastewater treatment methods using polyvinyl alcohol beads are seen to be effective, reducing the use of sewage waste plant construction sites and able to avoid the use of non-recyclable materials such as plastics and synthetics. [ABSTRACT FROM AUTHOR]

The mining industry is confronted with substantial challenges in achieving environmental sustainability, particularly regarding water usage, waste management, and dam safety. The increasing global demand for minerals has led to increased mining activities, resulting in significant environmental consequences. By 2025, an estimated 19 billion tons of solid tailings are projected to accumulate worldwide, exacerbating concerns over their management. Tailings storage facilities represent the largest water sinks within mining operations. The mismanagement of water content in tailings can compromise their stability, leading to potential dam failures and environmental catastrophes. In response to these pressing challenges, the mining industry is increasingly turning to innovative solutions such as tailings dewatering and water reuse/recycling strategies to promote sustainable development. This review paper aims to (I) redefine the role of mine tailings and explore their physical, chemical, and mineralogical characteristics; (II) discuss environmental concerns associated with conventional disposal methods; (III) explore recent advancements in dewatering techniques, assessing their potential for water recovery, technical and economic constraints, and sustainability considerations; (IV) and present challenges encountered in water treatment and recycling within the mining industry, highlighting areas for future research and potential obstacles in maximizing the value of mine tailings while minimizing their environmental impact.

One of the most important methods of optimising water consumption is grey water recycling. From a technological point of view, the treatment of grey water guarantees that it can be reused for domestic or corporate purposes, but it raises the issue of the social acceptance of the use of such water. This study aimed to assess the possibility of using grey water in households in Poland. The originality of this research study lies in the application of the PROFIT method for the separate construction of models of the benefits of grey water according to user groups. Four groups were identified, differentiated by gender and age; age and possession of an irretrievable water meter; gender and place of residence; place of residence and possession of an irretrievable water meter. To answer the formulated research questions, a diagnostic survey method was used, in which 807 randomly selected respondents from all over Poland were surveyed. The results of the survey indicate that homeowners perceive the potential use of grey water as beneficial, pointing most often to the following factors: rebuilding groundwater levels, reduced extraction of drinking water from rivers and other water bodies, and increased vegetation growth. On the other hand, they are concerned about the need to reconstruct the existing water and sewerage systems in order to produce drinking water from grey water as well as about the high cost and parameter stability of drinking water produced from grey water. Furthermore, men and older people attribute less importance to measures related to the introduction of good practices based on the reuse of recycled water in water management. Women, on the other hand, appreciate almost all opportunities to use grey water to a greater extent than men.

Microalgae hold promise as a sustainable source of biofuels and bioproducts but their commercial development is impeded by high cultivation costs, primarily for growth nutrients, and concerns about the water-intensive nature of algae cultivation. As a result, minimizing water and nutrient input is imperative to reducing algal operating costs, while enhancing the sustainability of future algal biorefineries. However, spent media recycling often results in the accumulation of growth inhibitors, such as free fatty acids, polysaccharides, polyunsaturated aldehydes, and humic acid, which negatively affect algal growth and productivity. In this review, we critically assess media recycling research findings to assess the advantages and disadvantages of spent media reuse for a wide range of algae strains. Particular emphasis is placed on strategies to overcome growth inhibition through spent media treatment processes, such as ultraviolet oxidation, activated carbon, ultrasonication, microfiltration, crop rotation, and nutrient replenishment. [ABSTRACT FROM AUTHOR]

Treatment of effluents discharged from mechanical machining of copper and copper alloys for removal of cutting oils and toxic copper ions by electrocoagulation was studied using a cell containing two steel electrodes and a built‐in heat transfer facility. Current density, initial pH of the solution, temperature, starting pollutants' concentrations, amount of NaCl supportive electrolyte, and the impact of gas sparging were investigated. Response surface methodology was used to correlate % oil removal, % copper removal, and electrical energy consumption to the affecting variables. The results imply that the cubic model fits well with the experimental results. The electrocoagulation of oil and copper from waste solutions was optimized using the response optimizer. The simultaneous removal of oil and Cu2+ in the same cell could lower the operational and capital expenses of wastewater treatment. [ABSTRACT FROM AUTHOR]

Despite topical research, the study of flotation systems remains complex, multifaceted and water-intensive. Numerous physical and chemical factors are involved in the recovery of valuable minerals by flotation. While the chemistry of a system can be manipulated to improve the performance, the system is limited by the mineralogy of the incoming ore and the quality of the process water, which in most cases is not controlled. Recycling of onsite process water has become the norm for many operations; this recycling changes the water quality over time and may compromise the flotation process. This study seeks to understand the impact of ore feed grade on froth stability, entrainment, and flotation performance under varying water quality. The overarching aim is the development of a relationship through which the flotation performance may be predicted if the ore feed grade and water quality are known. [ABSTRACT FROM AUTHOR]

Due to water scarcity over the globe finding ways of re-using wastewater is becoming more and more essential so as to put less strain upon natural resources. This paper provides new insights in particular by introducing for the first time the necessity of taking a balanced approach when using pinch analysis; cooling water demand can be as important as energy demand for inland locations particularly when externalities are taken into account. This is particularly important for Kazakhstan which is a dry, inland country, where climate change is exacerbating issues around water usage. Recent sharp reductions in the flow of the Zhayik river in the Atyrau region of Kazakhstan has magnified the water shortage in the Atyrau region and forced the government to develop new water policies to address this most urgent and serious matter. This paper analysed the water consumption of the main water consumers, the Atyrau oil refinery (AR) with respect to the country's other refineries and found that there has been a significant performance gap. Recently modernisation at AR has sought to transition it from open loop wastewater treatment to closed loop wastewater treatment. Not only has this significantly reduced the water intake from the Zhayik river but there is now zero discharge to the evaporation ponds. Eliminating this discharge prevents soil and groundwater contamination. Conventional methods of wastewater treatment within the framework of modernisation project, called "Tazalyq", are able to remove the majority of contaminants. However, this is still not sufficient to deal with small stable oil droplets (<5 µm). Methods to further enhance the treatment such as membrane technology and segregation are discussed. The former can concentrate small stable droplets without further use of chemicals, and the permeate is quality water that can be recycled. Pilot plant results on the use of reverse osmosis to treat blowdown water are also included. Implementation of this process would reduce water demand by circa 10%. Such an addition to modernisation project would further reduce the water intake from Zhayik river. [ABSTRACT FROM AUTHOR]

Water reuse is a practical solution to augment water supplies in areas where water resources are increasingly scarce. Water reuse technology is versatile and can be used to alleviate the different causes of water scarcity, such as groundwater depletion or increased availability of brackish water. Treatment technologies can be tailored specifically to the end use of recycled water, focusing on these drivers that are region-specific, for a more cost-effective treatment system. This is called a "Fit-for-Purpose" strategy that is commonly implemented in any water reuse project. However, implementing water reuse can be challenging due to infrastructural requirements, economic issues, and social acceptance. To help navigate these challenges, this article provides a comprehensive review of water reuse cases and presents guidelines that can act as a reference framework for future water reuse projects. This article also makes the case for implementing water reuse in the Greater Chicago area as a means of alleviating pressure on withdrawals from Lake Michigan. [ABSTRACT FROM AUTHOR]

Semiconductor manufacturing is a rapidly growing industry and water-intensive industry. Water strategy formulation and decisions can be crucial factors in realizing the sustainable development of the semiconductor industry. This study surveyed the sustainability reports of 24 semiconductor corporations and investigated their water strategies and practices. Water targets proposed in the early stage of the 21st century are summarized. Water recycling, reuse, and restoration were the main strategies. Reverse osmosis played a dominant role in water treatment and reclamation. Classified wastewater collection and separate treatment systems have contributed greatly to improvement of water recycling rate in industrial parks. Finally, a future water cycle system for semiconductor manufacturing parks is proposed, which comprises water source, water use and recycling, and water discharge. This study is of theoretical and practical significance for the formulation and implementation of water strategies in the semiconductor industry to help accomplish its sustainable development with rapid growth.

Israel has set ambitious goals in terms of the widespread adoption of desalination and water recycling technologies. Policymakers in Israel consider these technologies as the key to improve urban water security but knowledge of stakeholder views on this policy approach is not well established. We deployed the Q-methodology, a qualitative–quantitative approach, to empirically determine social perspectives on desalination and water recycling across a wide range of stakeholders in the Israeli water sector. We identified the following four distinctive social perspectives: (1) desalination should be the option of last resort; (2) desalination is moving us to an infinite resource; (3) equating savings to resources is a dangerous illusion; and (4) desalination is (risky) electric water. A common characteristic of these perspectives is the belief that desalination is necessary for a water-secure country, but desalination should not be the only source of drinking water in Israel. Our findings indicate that Israeli stakeholders show complex and contingent understandings of the pros and cons of desalination and water recycling and the risks involved in too much reliance on a limited number of water sources. We discuss the potential implications of our findings for water management and security in Israel and other places with water scarcity concerns. HIGHLIGHTS Using the Q-method, we identified four social perspectives on desalination and water recycling in Israel.; Stakeholders believe that desalination provides water security, but it should not be the only water source.; Stakeholders focus on the positive and negative aspects of water practices.; The link between desalination and peace was a point of contention.; Israeli stakeholders understand the pros and cons of desalination and water recycling.;

To implement a circular economy for water recycling and its optimal use, it is imperative to understand the behaviours of farmers and the farming systems they belong to because psychological effects usually influence and sometimes weaken technical solutions. The present study addresses farmers' behaviours in rice-fish farming systems towards a circular economy with an emphasis on water recycling. Using the theory of planned behaviour and structural equation modelling of partial least squares (PLS-SEM), the factors determining the intentions and behaviours of 500 farmers in these systems toward the circular economy were evaluated. The results show that attitudes (β = 0.271), subjective norms (β = 0.174), and perceived behavioural control (β = 0.215) positively influence farmers' intention in the rice-fish farming systems for the better implementation of water recycling methods. Additionally, farmers' intentions (β = 0.145), attitudes (β = 0.115), perceived behavioural control (β = 0.291), pressures (β = 0.109), barriers (β = −0.286), and enablers (β = 0.117) affect the behaviour of these systems toward the circular economy positively. In this regard, perceived behaviour control and barriers have the strongest positive and negative effects on the circular economy, respectively. Our study shows that most rice-fish farming systems have a positive intention, but they have failed in implementing the best practices of circular economy development with an emphasis on water recycling due to some important barriers. The research proposes some measures to reduce the gap between intention and behaviour and the accomplishment of the circular economy in the context of water. [ABSTRACT FROM AUTHOR]

Fresh water is an increasingly scarce resource in both urban and rural development. As a response to this challenge, non-potable water reuse is on the rise. This research explored a potential off-grid system for water purification, consisting of a staircase wetland with terracotta pot plants working as a filter for greywater. This study further investigated the physicochemical properties of greywater and the soil before and after wetland purification. The removal of total suspended solids, total coliforms, fecal coliforms, etc., was always between 90 and 99%. Results show that the filtered water satisfied all requirements for water reuse, e.g., a pH of 7–7.5 and a turbidity < 5 NTU. This research then uniquely investigated the effect of greywater on soil microbes and soil biomass using soil DNA extraction and the tea bag index testing method. The filtered greywater absorbed by soil decomposed the soil faster (66% for green tea) and stabilized it better compared to tap-water-absorbed soil or unfiltered greywater. DNA generation sequencing revealed no significant differences in alpha diversity between the control and treatment samples. The beta diversity differences were significant. This nature-based solution can lead to reduced loads on the sewage system, resulting in less wastewater generation. [ABSTRACT FROM AUTHOR]

Aims The growing need to access recycled water as a source for drinking water supply necessitates management of perceived risks. This study aimed to use quantitative microbial risk analysis (QMRA) to evaluate microbiological risks of indirect water recycling. Methods and Results Scenario analyses of risk probabilities of pathogen infection were conducted to investigate four key quantitative microbial risk assessment model assumptions: treatment process failure, drinking water consumption events per day, inclusion or exclusion of an engineered storage buffer, and treatment process redundancy. Results demonstrated that the proposed water recycling scheme could meet WHO pathogen risk guidelines of ∼10−3 annual risk of infection under 18 simulated scenarios. [ABSTRACT FROM AUTHOR]

Urban centers around the world are grappling with the challenges associated with population increases, drought, and projected water shortages. Potable water reuse (i.e., purification of municipal wastewater for reuse as drinking water) is an option for supplementing existing water supplies. Public perception research on potable water reuse has predominantly employed surveys with multiple‐choice questions that constrain survey respondents to describe their concerns by choosing from several response options. This research examines hundreds of write‐in responses to a large public survey in Albuquerque, New Mexico, to provide a detailed analysis of residents' questions and concerns about potable water reuse. Findings demonstrate that allowing respondents to voice their actual concerns adds richness and nuance that cannot be obtained from multiple‐choice response data alone. Especially with controversial resource considerations, such as potable water reuse, planners would benefit from a full understanding of the problem before engaging with the community. [ABSTRACT FROM AUTHOR]

Water resources are under pressure worldwide, resulting in scarcity and deterioration of freshwater quality. According to European directives, we could reduce the pressure on water resources in urban areas by increasing the reuse of treated wastewater, reducing the impact on water bodies, and promoting water recycling through multiple uses of urban wastewater. Besides the need to address water supply challenges, wastewater treatment systems show environmental stewardship and innovative practices. Using reclaimed water for agricultural irrigation is gaining interest because of the drought conditions experienced in Europe over the past few years. Furthermore, using treated wastewater for agricultural irrigation may help to restore nutrients (N and P) to natural biogeochemical cycles. This review highlights the importance of water reuse, current legislation, and existing technologies to implement in wastewater treatment systems to meet the minimum requirements to produce reclaimed water to reuse in agricultural irrigation. [ABSTRACT FROM AUTHOR]

Inappropriate fertilisation results in the pollution of groundwater with nitrates and phosphates, eutrophication in surface water, emission of greenhouse gasses, and unwanted N deposition in natural environments, thereby harming the whole ecosystem. In greenhouses, the cultivation in closed-loop soilless culture systems (CLSs) allows for the collection and recycling of the drainage solution, thus minimising contamination of water resources by nutrient emissions originating from the fertigation effluents. Recycling of the DS represents an ecologically sound technology as it can reduce water consumption by 20–35% and fertiliser use by 40–50% in greenhouse crops, while minimising or even eliminating losses of nutrients, thereby preventing environmental pollution by NO3− and P. The nutrient supply in CLSs is largely based on the anticipated ratio between the mass of a nutrient absorbed by the crop and the volume of water, expressed as mmol L−1, commonly referenced to as “uptake concentration” (UC). However, although the UCs exhibit stability over time under optimal climatic conditions, some deviations at different locations and different cropping stages can occur, leading to the accumulation or depletion of nutrients in the root zone. Although these may be small in the short term, they can reach harmful levels when summed up over longer periods, resulting in serious nutrient imbalances and crop damage. To prevent large nutrient imbalances in the root zone, the composition of the supplied nutrient solution must be frequently readjusted, taking into consideration the current nutrient status in the root zone of the crop. The standard practice to estimate the current nutrient status in the root zone is to regularly collect samples of drainage solution and determine the nutrient concentrations through chemical analyses. However, as results from a chemical laboratory are available several days after sample selection, there is currently intensive research activity aiming to develop ion-selective electrodes (ISEs) for online measurement of the DS composition in real-time. Furthermore, innovative decision support systems (DSSs) fed with the analytical results transmitted either offline or online can substantially contribute to timely and appropriate readjustments of the nutrient supply using as feedback information the current nutrient status in the root zone. The purpose of the present paper is to review the currently applied technologies for nutrient and water recycling in CLSs, as well as the new trends based on ISEs and novel DSSs. Furthermore, a specialised DSS named NUTRISENSE, which can contribute to more efficient management of nutrient supply and salt accumulation in closed-loop soilless cultivations, is presented.

Water conservation is a critical issue, particularly in arid countries and countries that suffer a lack of natural water resources. Jordan is one of the most water-scarce countries in the world; this fact has forced the search for alternative sustainable solutions. With the support of several regional and international organizations, tens of projects were implemented across the country over the past 30 years that aimed to reuse greywater in rural communities. The current review provides a wide overview of Jordan's experience in greywater treatment and its reuse for non-potable purposes in rural areas. To the best knowledge of the authors, the present review is the first to assess the Jordanian experience in this field. Many governmental authorities and non-governmental organizations have been involved in Jordan's experience. The greywater reuse systems were established to achieve advantageous environmental and socio-economic consequences on the rural communities. The strategy of greywater treatment was based on a local on-site greywater treatment system in households or the so-called ‘autonomous water management’. The applied greywater treatment technologies in households were found efficient in rendering greywater adequate for agricultural uses. However, further improvements and territorial expansion of the experiment are needed. HIGHLIGHTS The manuscript provides a wide overview of Jordan's experience in greywater treatment and reuse.; Tens of projects have been experimented over a period of three decades.; Reuse of greywater was implemented in rural areas that severely suffer from lack of water resources.; Most projects are based locally using on-site household implemented systems.; They provided a valid support to socio-economic benefits to urban region inhabitants.;

Tailwater-based hydroponic vegetable is a promising strategy for domestic wastewater recycling. However, the effect of residual antibiotics on the hydroponic vegetable system and the relation between hydroponic culture parameters and the residual water quality are still unclear. Here, the typical antibiotic Levofloxacin (LVFX) was employed, and the effect of LVFX (5 mg/L) on the residual water quality, plant growth and microbial community of water spinach hydroponic culture system were investigated under different hydraulic residence times (HRT). Obvious toxic effects on water spinach were observed, and the highest removal rate of LVFX (about 6 %) and TN (25.67±1.43 %) was observed when HRT was 7 days. Hydroponic culture increased the microbial abundance, diversity, and microbial community stability. To optimize the hydroponic culture, actual sewage plant tailwater spiked with 20 μg/L LVFX, along with three common planting substrates (sponge, ceramsite, and activated carbon) were used for the hydroponic culture of lettuce (seasonal reasons). The inhibition effect of LVFX on the removal of NO 3 --N and TN was observed even as the LVFX concentration decreased significantly (from 14.62 ± 0.44 μg/L to 0.65 ± 0.07 μg/L). The best growth situation of lettuce and removal rates of NH 4 +-N, NO 3 --N, TN, especially LVFX (up to 95.65 ± 0.54 %) were observed in the activated carbon treated group. The overall results indicate the negative effect of residual antibiotics on the hydroponic vegetable systems, and adding activated carbon as substrate is an effective strategy for supporting plant growth and controlling discharged risk. [Display omitted] • Toxic effects of Levofloxacin on water spinach growth were observed in tailwater-based hydroponic culture system. • Hydroponic culture increased the microbial abundance, diversity and microbial community stability. • Levofloxacin affects the removal rates of NH 4 +-N, NO 3 --N, TN, TP even at a low concentration of 20 μg/L. • Using activated carbon as planting substrate is favorable for supporting plant growth and controlling discharged risk. [ABSTRACT FROM AUTHOR]

Schematic diagram of a more sustainable biorefinery route through reusing the aqueous phase into the HTP process. [Display omitted] • The technique of aqueous phase recycling was proposed for biomass pretreatment. • Enhanced hemicellulose dissolution was obtained by aqueous phase recycling. • In-depth insights into what happened to lignocellulose were conducted. • Organic acids-induced intensification effects occurred in the circulating HTP. • Enhanced energy efficiency and suppressed CO 2 emission was achieved. Hydrothermal pretreatment (HTP) has received huge progress in converting biomass waste into available products at a large scale, but challenges in massive water input and wastewater output still block sustainable biorefinery future. Herein, a circulating hydrothermal technique was proposed by reusing the process wastewater into the next HTP process to enhance energy efficiency and suppress the environmental burdens. During hydrothermal liquid (HL) recycling, the variation of lignin chemical structure, cellulose accessibility, and soluble components were investigated for an in-depth understanding of what happened to lignocellulose. An enhanced hemicellulose dissolution (from 78.1 % to ∼ 85 %) was achieved by the aqueous phase recycling. The reactions of dehydration and polymerization occurred during the circulating HTP process, which contributed to the generation of pseudo-lignin on the cellulose surface, causing a slight weakening of cellulose accessibility. Meanwhile, the organic acid-catalyzed hydrothermal process can facilitate the cleavage of lignin β -O-4 ether linkage and condensation reaction, endowing its potential amphiphilic properties. An in-depth analysis of the evolution of HL components substantiated the potential intensification effect on biomass deconstruction by the generation of hemicellulose-derived organic acids. Life cycle assessment revealed that the circulating HTP technique resulted in about a 29 % reduction in primary energy depletion and an order of magnitude reduction in CO 2 emissions as opposed to that of the conventional one. This work unveils the structure evolutions of lignocellulose clearly during the HL recycled process, and also highlights a feasible route for the sustainable biorefinery. [ABSTRACT FROM AUTHOR]

• Frother removal for water recycling in mineral processing/flotation was investigated. • Insoluble β-cyclodextrin polymer particles were prepared via emulsion polymerisation. • Analysis of the frother, Interfloat F236N, revealed a complex mixture of alcohols. • Polymer particles allowed the removal of the frother components from solution. • Frother components with larger hydrophobic segments were preferentially adsorbed. The inclusion complexation capabilities of cyclodextrins permit them to mediate the adsorption of hydrophobic molecules. Though often associated with pharmaceutical formulations these properties afford a capacity for the extraction of appropriate hydrophobic guest molecules within industrial processes, such as water reclamation from frother contamination within mineral flotation circuits. Industrially applied flotation frothers largely comprise of a mixture of aliphatic alcohols, many of which are known to form stable inclusion complexes with beta-cyclodextrin (β-CD). Cross-linking of β-CD with epichlorohydrin through an emulsion polymerization process, afforded water-insoluble β–CD polymer particles as an effective adsorbent material for frother sequestration. Herein the capacity of these particles to adsorb frother molecules from aqueous solutions is presented. The composition of the industrially relevant frother Interfloat™ F326N, used predominantly for copper-sulfide ore flotation, was firstly elucidated using gas chromatography mass spectrometry. These identified components were then shown to be adsorbed by the β-CD polymer particles, demonstrating the successful sequestration of specific frother molecules from aqueous solution. The results of this study indicate that filtration media based on water-insoluble β-CD polymer particles may provide a viable means of removing frother contamination from recycled process waters. Further, this filtration media may find use in other water purification applications where contamination with organic molecules is of concern. [ABSTRACT FROM AUTHOR]

In closed-loop soilless culture systems, the increase of the electrical conductivity (EC) caused by Na+ accumulation is a major bottleneck for recycling of the nutrient solution if water sources are used which contain Na+ at substantial concentrations. Currently, the recommended nutrient concentrations for the root zone of tomato exceed those for maximising yield, aiming to induce a moderate salinity stress to enhance fruit quality. A new strategy for Na+ accumulation management is proposed, which gradually reduces the target concentrations of macronutrients except for P in the root zone in proportion to the accumulation of Na+, considering a minimum safety threshold, while maintaining the mutual ratios between them constant. The algorithm developed to support this new strategy was applied via the Decision Support System NUTRISENSE (https://nutrisense.online/) in tomato grown in mineral wool in a closed-loop soilless cropping system. The new strategy was compared with the standard strategy of maintaining constant nutrient concentrations in the root zone. The results demonstrate the efficiency of the new strategy to control the EC in the root zone while ensuring a balanced nutrition of the plants. By applying this strategy, the losses of nitrate and phosphorus due to discharge of drainage solution (DS) were reduced by 25.5 % and 9.20 %, respectively, while avoiding yield losses due to salinity stress, and increasing water productivity (WP) and agronomic efficiency of nitrogen (AE N). Nevertheless, the new strategy could not fully eliminate the need to discharge DS when raw water with a Na+concentration of 4 mM was used to prepare nutrient solution. • Compensation of Na accumulation by lowering macronutrients in drainwater reduced N losses by 25 % in soilless tomato. • Compensating for Na accumulation by lowering target macronutrients in drainwater increased water productivity. • Reduced nutrient concentrations in the root zone to compensate for Na increase did not affect plant nutrient status. • Na increase up to 21 mM in drainwater of soilless tomato compensated for by reduced nutrients did not affect yield. [ABSTRACT FROM AUTHOR]