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While phytoremediation has been widely employed for greywater treatment, this system suffers from the transfer of considerable amounts of surfactants to the aquatic environment through partially treated effluent and/or exhausted plant disposal. Hence, this study focuses on greywater phytoremediation followed by recycling the spent plant for preparing an adsorbent material used as post-treatment. P. crassipes was used to operate a phytoremediation unit under 23 °C, 60% relative humidity, plant density (5–30 g/L), dilution (0–50%), pH (4–10), and retention time (3–15 days). The optimum condition was 12.7 g/L density, 34.0% dilution, pH 8.4, and 13 days, giving chemical oxygen demand (COD), surfactant, and NH4-N removal efficiencies of 94.62%, 90.45%, and 88.09%, respectively. The exhausted plant was then thermally treated at 550 °C and 40 min to obtain biochar used as adsorbent to treat the phytoremediation effluent. The optimum adsorption process was biochar dosage of 1.51 g/L, pH of 2.1, and 137 min, providing a surfactant removal efficiency of 92.56%. The final discharge of this phytoremediation/adsorption combined process contained 8.30 mg/L COD, 0.23 mg/L surfactant, and 0.94 mg/L NH4+-N. Interestingly, this approach could be economically feasible with a payback period of 6.5 years, 14 USD net present value, and 8.6% internal rate of return. NOVELTY STATEMENT: The research succeeded in treating greywater by phytoremediation followed by recycling the exhausted P. crassipes plant to prepare an adsorbent material used in the post-treatment phase, giving an economically feasible scenario with 6.5-year payback period. [ABSTRACT FROM AUTHOR]

Water scarcity presents a pressing challenge in Egypt, exacerbated by factors such as population growth, urbanization, and climate change impacts. With over 95% reliance on the Nile River for freshwater supply, Egypt's water resources are strained, particularly with a population exceeding 100 million. Egypt's arid climate intensifies water scarcity, necessitating sustainable management strategies. This study explored greywater treatment as a solution to alleviate water scarcity in Egypt, investigating its technical feasibility, economic viability, and environmental benefits. Greywater, derived from domestic activities, is an underutilized resource that can be reclaimed and treated for reuse, reducing demand for freshwater sources. Through greywater treatment systems, households and communities can recycle water, conserve resources, and mitigate pollution. The study investigated using polymers as a coagulant in greywater treatment, examining its efficacy in removing contaminants and improving water quality. Experimental trials were conducted to evaluate the performance of polymer addition in greywater treatment compared to conventional methods. Results demonstrate that polymer addition reduces turbidity, suspended solids, and organic pollutants in greywater. Poly aluminum chloride (PAC) polymer, in particular, exhibits strong coagulation capabilities, versatility across pH ranges, and high efficiency in contaminant removal. Additionally, PAC offers operational advantages such as low dosage requirements and reduced sludge production. [ABSTRACT FROM AUTHOR]

The microbial fuel cell (MFC) is considered a modern technology used for treating wastewater and recovering electrical energy. In this study, a new dual technology combining MFC and a specialized biofilter was used. The anodic materials in the system were crushed graphite, either without coating (UFB-MFC) or coated with nanomaterials (nano-UFB-MFC). This biofilter served as a barrier to retain and remove turbidity and suspended solids, while also facilitating the role of bacteria in the removal of organic pollutants, phosphates, nitrates, sulfates, oil and greases. The results demonstrated that both systems exhibited high efficiency in treating kitchen wastewater, specifically greywater and dishwashing wastewater with high detergent concentrations. The removal efficiencies of COD, oil and grease, suspended solids, turbidity, nitrates, sulfates, and phosphates in first UFB-MFC were found to be 88, 95, 89, 86, 87, 75, and 94%, respectively, and in Nano-UFB-MFC were 86, 99, 95, 91, 81, 88, and 95%, respectively, with a high efficiency in recovering bioenergy reaching a value of 1.8 and 1.5 A m−3, respectively. The results of this study demonstrate the potential for developing MFC and utilizing it as a domestic system to mitigate pollution risks before discharging wastewater into the sewer network. [ABSTRACT FROM AUTHOR]

Featured Application: This research underscores the effectiveness of using seashells and ceramic bricks as substrates in vertical flow CW for greywater treatment. The findings are particularly relevant for rural and semi-arid regions, where these low-cost, sustainable systems can enhance water quality. The study also provides valuable insights into optimizing macrophyte age and substrate materials, offering practical solutions for decentralized wastewater treatment in underserved areas. This technology can be particularly beneficial for decentralized wastewater treatment in communities with limited access to advanced infrastructure, offering a practical solution for improving water quality and sustainability in resource-constrained environments. Constructed wetland (CW) systems have been recognized as a sustainable technology for wastewater treatment that can be easily integrated into the local natural environment, offering both low cost and high efficiency. In this study, synthetic greywater was treated using a vertical subsurface flow CW operated in batch mode with 7-day cycles across two phases, operated in parallel: I, non-vegetated, and II, vegetated, with Echinodorus subalatus. The mixed filter bed was composed of seashells, ceramic brick fragments, and sand. No statistically significant differences (p > 0.05) were observed between the non-vegetated and vegetated phases for most parameters. The removal efficiencies of organic matter, anionic surfactants, and total phosphorus in the non-vegetated versus vegetated phases were (91.0 ± 3.8)% versus (94.0 ± 1.1)%; (71.9 ± 14.1)% versus (60.0 ± 9.5)%; and (35.2 ± 4.6)% versus (40.2 ± 15.5)%, respectively. Phosphorus removal exceeded values reported in the literature for both phases, primarily due to the calcium present in the seashells, which increased the electrical conductivity and hardness of the effluent compared to the influent. The macrophyte exhibited leaf desiccation, possibly due to contact with greywater and its young age (30 days), which may have negatively impacted the system's performance during the vegetated phase. [ABSTRACT FROM AUTHOR]

Considering the increasing need for optimal use of water resources, using types of waste water instead of part of the water for making concrete and also reducing the use of potable water in concrete is particularly important, especially in developing countries. Accordingly, this study aimed to investigate and reinforce using greywater as a potential alternative to mixing water in concrete. The specimens' fresh, hardened, and durable properties from 14 concrete mix designs containing six mixing water types, three natural zeolite levels (0, 10, and 20%), and two silica fume levels (0 and 8%) were tested to achieve that. Mixing waters in this study consisted of distilled water, raw greywater, diluted greywater (50% greywater, 50% distilled water), simulations of greywater's salt and organic pollutants, and synthetic greywater. The results showed that raw greywater reduced average compressive strength by 8%, while diluted greywater caused a 1.5% increase instead. Mixing water standards requirements were satisfied on both raw and diluted greywater cases. The results also showed that the impact of greywater on the durability properties of concrete was non-critical in most cases, while diluted greywater, even slightly (4%), improved bulk electrical resistance (RCPT). The test results of synthetic waters showed that reducing chemically active salts and/or organic pollution in greywater can effectively increase the performance of the produced concrete. Using 8% silica fume as cement replacement improved the compressive strength of greywater-made concrete by up to 16% and reduced the cracks and porosity of the specimens based on SEM images. On the other hand, using 20% natural zeolite as cement replacement increased surface (using Wenner probes) and bulk chloride ion penetration by 36 and 78%, respectively. Based on these results, silica fume and natural zeolite replacement are impressive tools to reinforce greywater-made green concrete so that it can properly rival and even replace regular concrete even when using more polluted greywater. Furthermore, these replacements can be great potential alternatives to wastewater dilution or treatments. [ABSTRACT FROM AUTHOR]

Climate change and high water consumption driven by population growth have led to water stress, affecting over 2 billion people worldwide yearly. In the face of scarce water resources, traditional sewage infrastructure, especially during extreme weather, can not handle the water load and leads to pollution in freshwater sources. Treatment of rainwater and graywater can be considered a potential water source to minimize freshwater consumption and enhance water sustainability, offering simple solutions in cities. Recently, the ability of plants to remove toxic metals from dirty waters through their roots have been utilized and then water reused. In this study, a small-scale domestic graywater treatment system was developed under greenhouse conditions as a nature-based solution. In the selection of plants, species naturally distributed in Düzce province, aquatic, riparian, and understory species were preferred. Plants in the system were supplied with graywater and stored. The plants’ purification levels and growth status under polluted water stress were examined. According to the results the amount of anionic substances in stored water, Asplenium scolopendrium L. was observed to have the highest treatment performance among the species. Although Lythrum salicaria L. and Carex pendula Huds. had a lower value compared to other species, they were shown to be a usable species in graywater treatment. Nasturtium officinale R. BR. had a low treatment value and was found to be a pollution-resistant species. As a result, the reuse of water is essential in today’s conditions where climate zones and species distributions are changing. As seen in this study; Although species from natural vegetation have different purification potentials, they offer the opportunity to be used to purify gray water. [ABSTRACT FROM AUTHOR]

This study explores the potential of converting domestic graywater into electrochemical energy as a sustainable energy solution amidst growing environmental concerns. Employing a custom-designed galvanic cell prototype, the research aims to transform the chemical energy in graywater into electrical energy through redox reactions, quantifying the electrical potential generated. Results demonstrate the prototype's success in generating an average no-load voltage of 5.1907 volts, effectively powering low-power devices like LEDs and validating the viability of greywater as an alternative energy source. However, the study acknowledges limitations such as the prototype's small scale and the potential impact of varied graywater compositions on energy efficiency, suggesting cautious application at larger scales. Future research directions include enhancing prototype efficiency and scalability, understanding the effects of different graywater compositions, and conducting long-term performance assessments. The study contributes to sustainable energy research by offering a novel approach to wastewater energy recovery, promoting environmental sustainability and efficient energy utilization. [ABSTRACT FROM AUTHOR]

The pressing issue of the impact of changing agricultural policies on the water, food, and energy nexus is of utmost importance in today's world. This issue is particularly critical in countries currently grappling with a severe water crisis. This work develops a national-level water, food, and energy (WFE) nexus model using a combination of system dynamics modeling (SDM) and agent-based modeling (ABM). The WFE model focuses on water resources, with agriculture being the primary user. A model agent was designed for agriculture which includes a variety of agricultural products with varying yields, blue water and greywater consumption, energy consumption, and land area under cultivation for each crop. This paper's systems dynamics model is intended for application to meet the nutritional needs of a country's population by balancing water and energy resources and consumption while maintaining food security. The model's application covers two scenarios in Iran, a country under severe water stress. The first scenario involves nutrient supply based on the current diet, while the second scenario suggests a lacto-ovo diet. The outcomes of this study reveal that both scenarios can would lead to water and energy savings. For example, the implementation of Scenario 1 and 2 can reduce the groundwater storage deficit that occurred during the five-year study period by approximately 65% and 85%, respectively. Furthermore, based on the high volume of water saved in both scenarios, the increase in the volume of greywater is deemed neither significant nor hazardous. Considering new policies of agricultural production can lead to a new balanced diet in terms of nutrients and energy, which can impact the achievement of sustainable WFE resources. The findings of this research could prove beneficial for national policymakers who seek to promote sustainable WFE resource management. [ABSTRACT FROM AUTHOR]

This study explores the optimization of iron electrocoagulation for treating laundry greywater, which accounts for up to 38% of domestic greywater. Characterized by high concentrations of surfactants, detergents, and suspended solids, laundry greywater presents complex challenges for treatment processes, posing significant environmental and health risks. Utilizing response surface methodology (RSM), this research developed a second-order polynomial regression model focused on key operational parameters such as the area-to-volume ratio (A/V), current density, electrolysis time, and settling time. Optimal treatment conditions were identified: an A/V ratio of 30 m2/m3, a current density of 10 mA/cm2, an electrolysis duration of 50 min, and a settlement period of 12 h. Under these conditions, exceptional treatment outcomes were achieved, with turbidity removal reaching 94.26% and COD removal at 99.64%. The model exhibited high effectiveness for turbidity removal, with an R2 value of 94.16%, and moderate effectiveness for COD removal, with an R2 value of 75.90%. The interaction between the A/V ratio and electrolysis time particularly underscored their critical role in electrocoagulation system design. Moreover, these results highlight the potential for optimizing electrocoagulation parameters to adapt to daily fluctuations in greywater production and meet specific household reuse needs, such as toilet flushing. This tailored approach aims to maximize contaminant separation and coagulant efficiency, balance energy use and operational costs, and contribute to sustainable water management. [ABSTRACT FROM AUTHOR]

This study investigates a rice husk waste‐based filter (RHW‐BF) for the treatment of graywater (GW) and primary treated wastewater (PTW). The RHW‐BF comprises three layers: coarse sand, chemically modified rice husk (MRH), and gravel. Continuous runs (Run I, II, III) assessed chemical oxygen demand, total suspended solids, total dissolved solids, and turbidity removal. Run (I) for GW achieved high removal: 73.7 %, 73.4 %, 74.6 %, and 92.6 %. Subsequent runs showed decreasing efficiencies due to media saturation. Similar trends occurred for PTW, with Run (I) achieving significant removal: 70.3 %, 69.0 %, 44.2 %, and 90.2 %. MRH particles played a crucial role in sustainable pollutant removal. The study compares treated wastewater with the World Health Organization and Egyptian limits, demonstrating its suitability for reuse in irrigation, agriculture, or sewer discharge. [ABSTRACT FROM AUTHOR]

The obsolete efficiencies in conventional centralized wastewater treatment systems call for implementation of source separation and treatment of wastewater. Approximately 60–75% of domestic wastewater is attributed to greywater, which could be reused to combat freshwater crisis. The present study investigates qualitative and quantitative attributes of greywater from different sources in High-Income Countries (HICs) and Low-Income Countries (LICs). The quantity of greywater generation is positively correlated with country's per capita income, but feebly negatively correlated with temperature. Kitchen source is the highest contributor of total suspended solids (134–1300 mg/l), whereas in case of turbidity, laundry is the major contributor (39–444 NTU). Also, kitchen greywater is characterized by comparatively high biochemical oxygen demand (BOD) of 100–1850 mg/l, low pH of 5.6–8, and elevated total nitrogen (TN) of about 1.5–48 mg/l. The high pH (7.3–10) and chemical oxygen demand (COD) levels (58–2497 mg/l) in laundry greywater are due to usage of sodium hydroxide-based soaps, while usage of wash detergents containing phosphates like sodium tripolyphosphate contribute to high total phosphorus (TP) (0.062–57 mg/l). The qualitative characteristics of greywater in HICs are perceived to be superior compared to LICs. Furthermore, the most widely used physicochemical, biological, and advanced oxidation treatment technologies for greywater are outlined briefly. It can be observed that economical treatment systems like phytoremediation or biological technologies combined with sand filtration systems can be implemented to treat greywater with high organic content in LICs, whereas in HICs where greywater is generated in large quantities, electro-coagulation combined with advanced oxidation technologies can be used to treat its higher COD levels. Highlights: Assessment of variations in qualitative and quantitative characteristics of greywater from various sources and in HICs and LICs. The quantity of greywater generation is positively correlated with the per capita income, but feebly negatively correlated with the temperature aspect of the country. Kitchen is the major source of BOD5 and TN, while laundry is the major contributor of COD and TP in the greywater. [ABSTRACT FROM AUTHOR]

Summary: Water conservation is of particular importance for arid regions, including many Muslim-majority countries. With the added pressures of human population growth and expansion and global climate change, water conservation efforts are imperative to extending the life of current water supplies as well as to sourcing water treatment methods that are religiously congruent. We review Qur'anic verses that address water usage and conservation. We searched the English translations of the King Fahd Complex for the Printing of the Holy Qur'an and the King Saud University Electronic Moshaf Project for Qur'anic scripture related to water and water conservation. A total of 25 verses were found that related to creation, water usage for agriculture and food provision/production and as a common resource for humanity. Qur'anic scripture encourages gratitude for water and wise stewardship of this resource. Specific prohibitions against the reuse of water (e.g., treated water) were not found, and recent Islamic literature supports the use of cleansed greywater. Treated greywater may thus be an additional source for agricultural needs, thus reducing the stress placed on already limited water supplies. Water conservation falls within Qur'anic scripture. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the financial feasibility of rainwater harvesting and greywater reuse in a multifamily building located in Florianópolis, Brazil. A building, consisting of two blocks with 60 flats each, was chosen to obtain data about the number of residents, building characteristics, potable water consumption, and rainwater and greywater demands (obtained by means of questionnaires and water measurements). The financial feasibility analyses considered rainwater and greywater systems separately and together. The impact on the urban stormwater drainage system was evaluated through the reduction of stormwater runoff. The energy consumption in the operational phase of each system was estimated through the amount of energy consumed by the motor pumps to supply one cubic meter of water. The potential for potable water savings through the use of rainwater—that supplies water for washing machines—was approximately 6.9%. The potential for potable water savings through the use of greywater—that supplies water to toilets—was approximately 5.7%. Both systems were feasible. The payback period for rainwater harvesting systems ranged from 57 to 76 months. For greywater systems, the payback period ranged from 127 to 159 months. When considering both systems working together, the payback period ranged from 89 to 132 months. The rainwater harvesting system can reduce 11.8% the stormwater volume destined to the urban stormwater drainage system in relation to the current contribution volume. Energy consumption was approximately 0.56 kWh/m3 of treated water for the rainwater harvesting system and 0.89 kWh/m3 of treated water for the greywater system. Rainwater and greywater were considered economically feasible, especially for higher inflation scenarios. Furthermore, such systems are interesting alternatives in terms of impacts considering urban drainage and energy consumption. [ABSTRACT FROM AUTHOR]

The management of greywater and sanitation in South Africa's urban informal settlements is a pressing concern. This review critically examines the legal framework that governs greywater management in South Africa's informal settlements, aiming to shed light on the existing regulations, gaps, and opportunities for sustainable greywater reuse. By scrutinizing the legal framework, the review identifies gaps and challenges in the regulatory environment, including inconsistencies, lack of clarity, and limited enforcement mechanisms. It explores the potential for international best practices to inform possible amendments to the existing legal framework. This was a quantitative research design utilizing a cross sectional survey model. Questionnaires were administered electronically to a sample of 17 municipal leaders from the City of Tshwane, City of Johannesburg and Buffalo City municipalities whose responsibilities were on water management. Descriptive statistics were employed in analysis of the data. Outcomes were reviewed against the alignment or the lack thereof with the SANS 1732:201x standards. This paper underscores the critical need for a coherent and robust legal framework to support responsible greywater management in South Africa's informal settlements. The paper's insights contribute to the ongoing discourse on water governance, shedding light on the pathways toward a more equitable water future. [ABSTRACT FROM AUTHOR]

Stormwater harvesting is a promising solution for global freshwater depletion, particularly in tropical regions with abundant rainfall. However, it is not widely used due to the lack of suitable treatment technologies for domestic applications. Multi-stage filtration (MSF) is an effective integrated treatment technology that provides a cost-effective alternative for stormwater treatment. This study investigated MSF's capacity for treating stormwater at different stages. The MSF designed and built comprised the down-flow roughing filter (DRF) and slow sand filter (SSF). The results achieved by the MSF for the treated effluents were: pH (7.1-8.1), temperature (27.6-29.4°C), electrical conductivity (EC) (100-190 µS/cm) and total dissolved solids (TDS) (70-130 mg/L). Turbidity removal efficiency of the MSF was in the range of 36-99% (5.825-164.05 NTU) and the overall average removal efficiency of the MSF was 74%, 90% and 86% for total coliforms (TC) (360-11 800 CFU/100 mL), faecal coliforms (FC) (0-1 300 CFU/100 mL) and Enterococcus spp. (120-1 400 CFU/100 mL), respectively. The study identified stormwater reuse potentials based on international guidelines and benchmarks. For the treated effluent, pH, temperature, EC and TDS were all within the permissible limits for toilet, laundry, bathing, recreational and agricultural water reuse, while turbidity suited agricultural (non-food crop) and restricted urban reuse. 46% of the effluent was suitable for recreational purposes as this satisfied the 50 NTU standard. 62.5% of the effluent satisfied the FC standard for toilets and urinals and agricultural reuse (non-food crop) purposes, while 87.5 % of the effluent satisfied urban reuse purposes (restricted access). 66.67% of the effluent satisfied the Enterococcus spp. standard for agricultural reuse (non-food crop). All treated effluents satisfied the TC bathing standard. This study shows that after minimal disinfection, stormwater effluents offer potential reuse in household applications, thereby reducing potable water demand. [ABSTRACT FROM AUTHOR]

BACKGROUND AND OBJECTIVES: Jordan's limited water resources have reduced daily water consumption, leading to a highly concentrated greywater production rate of 54 million cubic meters per year. The presence of nitrate ions, total dissolved solids, total suspended solids, chemical oxygen demand, and biological oxygen demand in greywater poses excellent environmental and health risks when disposed untreated. Water scarcity directly impacts water and food security and is expected to intensify at the current resources management practices. The significance of the current and predictable water shortage in the context of sustainable development and the presence of new technologies brought further attention to utilizing non-conventional water sources. Reclamation of treated wastewater, greywater, brackish, and seawater desalination is Jordan's water budget's only non-conventional water resource. This study aims to address Jordan's water scarcity crisis by developing a low-energy, solar-powered greywater filtration system using natural materials while ensuring compliance with Jordanian standards for safe agricultural applications. METHODS: Several treatment methods have been proposed; however, most of these systems require high to medium energy levels for treatment purposes. Hence, the running cost of the system is relatively high. To address this issue, a four-stage, low-energy, green, and decentralized solar filtration system for greywater treatment has been developed, which uses natural materials available in Jordan and activated carbon to reduce organic and solids content and remove pathogens. The system also uses hot water generated by a Photovoltaic solar system to sanitize the greywater, a novel concept of approach for sanitization. This innovative system is powered entirely by solar energy and can be installed in individual homes. FINDINGS: The results of the developed solar filtration system were very efficient in reducing turbidity, chemical oxygen demand, and Escherichia coli removal: 92, 95, and 100 percent, respectively. Furthermore, the system showed a high potential for total coliforms and Escherichia coli inactivation, reaching 4.64 and 3.15 log units, respectively. Product water meets Jordan standards, ensuring safe reuse for irrigation applications. The findings of this study highlight the satisfactory performance of the developed greywater solar filtration setup. The economic feasibility analysis demonstrates that the proposed system is economically viable and financially sound. The system's reliance on solar energy and the absence of consumables contribute to its sustainability. They are addressing sustainable practices in greywater treatment in addition to water scarcity concerns. CONCLUSION: The treated greywater, obtained through the series of treatment steps, including solar disinfection, successfully met the Jordanian standards for safe reuse. The substantial reduction of Escherichia coli and total coliforms to acceptable levels demonstrates the treatment system's effectiveness in generating pathogen-free greywater, suitable for a wide range of applications. The study concludes that the solar filtration setup consistently delivers high-quality, pathogen-free greywater, meeting stringent regulatory requirements. This innovative, sustainable system offers a viable solution to Jordan's water scarcity, introducing a new non-conventional water resource that requires no consumables (non-chemical, non-hazardous materials), thereby addressing sustainability concerns in greywater treatment. [ABSTRACT FROM AUTHOR]

There are two distinct directions of agricultural development when considering only crops and livestock. They are integrated crops and livestock systems (ICLS) and separated crops and livestock systems (SCLS). When evaluating agricultural greywater footprint (GWF), nitrogen cycling and nitrogen fixation in ICLS reduce nitrogen emissions always neglected. A novel study that aims to efficiently use water and reduce water pollution in agriculture to guide investment between crops and livestock is appealing. Based on the panel data of 11 provinces in the Yangtze River Economic Zone from 2007 to 2018, we employ the slacks-based model to evaluate agricultural water use efficiency (AWUE). GWF plays an unexpected output in the model. Furthermore, we compare both AWUE and GWF between ICLS and SCLS. The results show: (i) ICLS produce approximately 4.76 million cubic meters GWF less than SCLS, 1.89% of total GWF emission of SCLS. The greywater footprint emissions of the province's unit-mass meat (GWFM) increased by an average of 26.30%. By contrast, the greywater footprint emissions of unit-mass grains (GWFG) decreased by an average of 27.37%. (ii) ICLS improves the AWUE of the province to the highest level of 10.78% compared with SCLS. (iii) If government allocates capital investment in crops and livestock freely, an additional 1% of crops investment would increase by 1.94% of GWFG while livestock could reduce GWFG by 2.12%. Investment in livestock is valid. [ABSTRACT FROM AUTHOR]

As an alternative wood source for biochar and a cost-effective renewable energy source, sustainable biomass production based on fast-growing willows irrigated with treated wastewater has been explored. Salix alba L. and Salix viminalis L. were selected for assessment of their potentially high woody biomass productivity and phytoremediation efficiency when irrigated with greywater treated by floating treatment wetlands. Both Salix species produced significantly (p < 0.05) high woody biomass in the second harvest, with a significantly higher fresh woody biomass weight with higher water content (53%) for S. viminalis compared to S. alba. The dry biomass weight of S. alba was greater than of S. viminalis at the first harvest. The element accumulations in substrates changed significantly after irrigation, with greywater compared to the raw substrate following this order: Mg > Fe > Al > Cr > Mn > Cd > Cu > B. Element concentrations accumulated in twigs of S. alba following this order: Ca > Mg > Na > Mn > Zn > Fe > Al > Cd > Cu > Cr > Ni > B, but for S. viminalis the order was Ca > Mg > Mn > Zn > Na > Fe > Al > Cd > Cu > Ni > Cr > B. The accumulations of Al, B, Ca, Fe, Mg, Mn, and Ni were significantly greater in S. alba leaves compared to their twigs, which showed significantly high accumulations of Na and Zn. The accumulations of Al, B, Ca, Fe, Mg, Mn, and Na were significantly greater in S. viminalis leaves compared to their twigs. [ABSTRACT FROM AUTHOR]

Due to increasing freshwater demand and limited availability of resources, conservation and recycling of greywater are getting attention worldwide. Greywater (GW) is considered a potential contender to different types of industrial wastewater in terms of recyclability, toxicity, and reusability. The reuse and treatment methodologies in the case of LGW mainly depend on parameters such as pH, Biochemical oxygen demand (BOD), Chemical oxygen demand (COD), Total dissolved solids (TDS), Total suspended solids (TSS), turbidity, ionic concentration, surfactants, and microbial growth. Available literature suggests that domestic as well as commercial laundries are major contributors to greywater around the globe. This paper presents the results of investigations conducted on the quantity and quality of greywater generated from domestic urban laundries. Various factors were observed that influence the quantity of generated LGW such as family size, type of washing (machine or manual), and composition of LGW influenced by the work profile of family members, etc. The average values of BOD, COD, TSS, TDS, turbidity, Chloride (Cl−), Sulphate (SO42−), Fluoride (F−), Nitrate (NO3−), and anionic surfactants as MBAS (methylene blue active substances) were observed as 265.73 mgL−1, 1754.67 mgL−1, 469.13 mgL−1, 1837.73 mgL−1, 281.8 NTU, 438.6 mgL−1, 87.93 mgL−1, 0.87 mgL−1, 6.83 mgL−1, and 16.45 mgL−1, respectively. The average concentration of Escherichia coli and total coliforms was observed to be 73.4 MPN/100 mL (most probable number per 100 mL) and 386.2 MPN/100 mL, respectively. The high values of selected parameters necessitate the planning of greywater treatment in urban locations for re‐utilization. This study also revealed that a huge amount of freshwater is being converted to greywater by domestic laundries that can be re‐utilized for non‐potable purposes after some treatment. [ABSTRACT FROM AUTHOR]

This paper presents reclamation of greywater using "Green-wall treatment system". A Green-wall of capacity 100 L/d has been implemented with the aim of greywater reclamation from a bathing water facility. The treatment system comprised of a degreasing tank of size 0.9 m x 0.9 m x 0.3 m for oil & grease removal, followed by a Green-wall. Removal of oil & grease has been done along with commonly observed pollutants in greywater, to prevent clogging of filler material. In stage-I studies, Green-wall pots are filled with 4-10 mm Ø inert filler material LECA and in stage-II, LECA is mixed with locally available coconut peat in equal proportion. Stage-I studies using LECA indicated that maximum achievable HRT is 12 h and the treated greywater with respect to BOD does not comply with USEPA (2012) norms for landscape irrigation. In stage-II, the optimized performance is observed at 16 &18 h HRT at hydraulic loading rate 67-70 L/m²/d, when compared with 14 and 12 h HRT. Treated greywater quality met the prescribed permissible limits with respect to BOD, TSS and FC and is observed to be innocuous in terms of the reuse options for agriculture and landscape irrigation. In stage-II, the BOD, COD, TSS and FC reduce from 48 to 10 mg/L, 58 to 18 mg/L, 96 to 10 mg/L and 400 CFU/ 100 mL to below detectable limits, respectively, at 18 h HRT. [ABSTRACT FROM AUTHOR]

The present study aims to investigate the efficiency of a combined cheese wastewater treatment approach involving coagulation with ferric chloride coupled with a photo-Fenton-like oxidation process for potential reuse in irrigation. Laboratory-scale tests were conducted, examining the effect of various operational parameters on the treatment process. Specifically, the effects of initial wastewater pH, coagulant dosage, decantation time for the coagulation process, and initial pH, chemical oxygen demand (COD) concentration, and Fe3+ and H2O2 dosages for photo-Fenton-like oxidation were studied. Coagulation was found effective at natural pH of 6 and showed a highest removal efficiency in terms of COD (50.6%), biological oxygen demand BOD5 (42.1%), turbidity (99.3%), and least sludge volume generation (11.8% v/v) for an optimum coagulant dose of 400 mg Fe3+ L–1 and 8 h of decantation time. Thereafter, photo-Fenton-like oxidation (Fe3+/H2O2/UVA-300W) of the pretreated cheese effluent enhanced the removal of COD, BOD5 and TOC to 91.2%, 91.4%, and 97.5%, respectively, using the optimized conditions (pH = 3; [Fe3+] = 5.0 × 10−4 mol L−1; [H2O2] = 0.2 mol L−1 and tirr = 24 h). This study also shows that the proposed combined process allowed a significant phytotoxicity reduction toward lentil seed germination. The obtained outcome was encouraging and supports the possible use of the treated cheese wastewater as an additional water source for agricultural irrigation. [ABSTRACT FROM AUTHOR]

This article explores the concept of irrigated urban agriculture (IUA) in rapidly urbanizing cities in the Global South. IUA plays a crucial role in supplying fresh food, particularly vegetables, to urban areas and contributes to community well-being by creating green spaces. However, IUA practices are often contested and ignored by regulatory authorities. The article argues for a contextual understanding of IUA practices and policies to promote sustainable urban water management and food security. It also discusses the complexities and challenges surrounding informal urban agriculture and emphasizes the need for governance approaches that recognize the dynamics of bottom-up development and address societal concerns. Additionally, the document highlights the importance of policies and institutions that support IUA and facilitate access to resources, as well as collaboration between different sectors and stakeholders. Overall, the article calls for a paradigm shift in governance arrangements to fully integrate IUA into formal urban development. [Extracted from the article]

In Pakistan, water scarcity is a major problem, continuously increasing with the increase of population. Unfortunately, untreated wastewater mostly aggravates this critical issue as it is disposed of directly in a water source. Traditional treatment technologies can effectively work but are economically not sustainable. This research aims to align with SDG6 "Clean Water and Sanitation" to address this challenging problem. Muslims across the globe utilize water for ablution five times a day, which is left untreated as greywater. Understanding the issue of untreated greywater, this research proposes a cost-effective filtration system for treating greywater in mosques on the University of Engineering and Technology (UET), Taxila campus by establishing a closed-loop system making it reusable. The filtration system comprises of Tea Waste Residue (TWR) as a filtration media with stratified layers of gravel and sand. The study comprises the characterization of wastewater and designing of a treatment plant as a feasible and sustainable option for treating greywater from mosques i.e., simple to install and operate, and aims to treat large volumes of water. The findings of the study recommend that the system can be implemented in mosques in Taxila and other parts of Pakistan, laundry wastewater, and car washing, ensuring it is environmentally and economically sustainable and minimizing the strain on natural water bodies. [ABSTRACT FROM AUTHOR]

Worldwide population growth and consumerism have elevated the water pollution problem to the top of the environmental priority list, with severe consequences for public health, particularly in agricultural countries such as India, where water scarcity is a big challenge. Hence, greywater has the potential to be one of the most sustainable options to meet the growing need for freshwater with satisfying treatment options. This study focused on the assessment of electrocoagulation coupled with the filtration and adsorption processes in continuous modes and different electrode arrangements including (Al-Fe-Al-Fe), (Fe-Al-Fe-Al), (Al-Al-Al-Al) and (Fe-Fe-Fe-Fe) to investigate the effect of specific flow rates (i.e., 0.05 and 0.1 liters per minute) on the removal efficiency. The findings show that a 0.05 lit/min flow rate produces a higher removal efficiency approximately between 85 to 90% with an energy consumption of between 0.5 to 4.75 KWh/m3 as compared to the 75 to 85% removal efficiency and 0.4 to 4 KWh/m3 energy consumption at a flow rate of 0.1 lit/min. The operational cost is variable and mainly depends upon the energy consumption; moreover, it was found that the optimal results and economy variation shown by the electrode assembly of Al-Fe-Al-Fe was between 20 to 22 Indian rupees at a 24 volt current density and in each combination of electrodes. [ABSTRACT FROM AUTHOR]

Concerns about decreasing urban water supplies and environmental degradation caused by existing water infrastructure have prompted research on more resilient and long-term water delivery systems. Greywater reuse has been proposed to expand local water supply portfolios while minimizing stress on existing ecosystems and infrastructure. Researchers have developed several technologies for greywater reusability and recycling. There are three primary treatment technologies for greywater treatment: physical, chemical, and biological. Besides traditional treatment methods, numerous advanced technologies have attracted interest in recent years, like membrane-based technology, improved electrocoagulation, nature-based solutions (constructed wetlands), and solar-based approaches. The cost comparison of existing technologies has also been examined. The current review focuses on the relevance of various technologies and their readiness level, global scenario, risks possibilities and modeling systems for greywater reuse. The issues and hurdles of greywater reuse sustainably have also been evaluated. This in-depth review study will set the basis for future research in greywater reusability. [ABSTRACT FROM AUTHOR]

A rise in population and urbanization demanded that a robust fecal sludge management (FSM) value chain be used to restructure the sanitation system throughout the world securely. A significant global need exists to adopt efficient and sustainable FSM. On-site sanitation systems (OSS) produce fecal sludge (FS). FS is produced when excreta and blackwater are combined and stored or treated, either alone or in combination with greywater. FS can be semisolid or slurry and raw or partially digested. Critical examination of FS characteristics, i.e., biochemical oxygen demand (BOD), chemical oxygen demand (COD), total solids (TS), and pathogen count, varies from 600–56,836 mg/l, 6656 to 201,200 mg/l, 830–123,000 mg/l, and 105 to 109E. coli/l of FS respectively. Helminth eggs range from 2500–25,000/l of FS. Public health and the environment are negatively impacted by septic tank overflows and the careless discharge of FS into open spaces affecting groundwater quality, water bodies, irrigation fields, open drains, places outside villages, etc. Thus, deciding on a proper treatment technology for FS before discharging it into open land or reusing FS is essential to create a pollution-free environment. This paper highlights the practices adopted for FSM under its different processes, such as collecting, characterization, treating, and reusing of on-site FS and bibliometric analysis on documents on fecal sludge. A thorough analysis has been carried out by reviewing all important literature available globally. [ABSTRACT FROM AUTHOR]

In this paper, greywater samples are collected from the kitchens of different types of buildings (residential and commercial) located in different districts within the city of Jeddah, Saudi Arabia. The collected samples are analyzed and compared with the potable water from the same region. The parameters investigated are pH, conductivity, total solids (TS), total dissolved solids (TDS), total suspended solids (TSS), total hardness, temporary hardness, permanent hardness, alkalinity, chloride, and biochemical oxygen demand (BOD). It was found that the amount of total suspended solids is very high in the greywater samples. It shows the presence of both temporary and permanent hardness. Their alkalinity values are greater than hardness. It may be due to the number, lifestyle, age of the occupants, presence of children, and social and cultural behavior of residents. The concentration of BOD level is very low, which shows that the greywater samples have lower concentrations of organic compounds. Design details of the greywater treatment plant are suggested based on the results of the analysis. This includes a screening chamber, grit chamber, settling tank, and filtration unit. The treated greywater is recommended for reuse for gardening, landscaping, and toilet flushing purposes. [ABSTRACT FROM AUTHOR]

Treatment and reuse of greywater for non-potable applications especially in scarce countries is a feasible option. In this study, a simple greywater treatment system consisting of a low-cost simple multi-media filter with biological contact aeration system was developed and installed in a selected household in Muscat, the capital of Oman. Monitoring and measurements were made to investigate the productivity and efficiency of this system in treating the greywater from laundry and shower sources. The greywater from the collected laundry and shower contained 360 mg/L of COD and 28.5 mg/L of BOD. The experimental results showed that the greywater treatment unit achieved more than 99% of turbidity removal, more than 74% of BOD removal, and more than 50% of COD removal. BOD removal was primarily achieved through bacterial degradation whereas COD removal was attributed to the adsorption of organic compounds by activated carbon. The effluent quality of the treated greywater fell within the standard level and can be safely reused for various non-potable applications. [ABSTRACT FROM AUTHOR]

The present case study - Sustainable Cerrado Subdivision Project in Arouca (Portugal) - proposes the implementation of a design solution that promotes 'sustainable neighborhoods', expanding the concept of 'sustainable homes'. This type of project results from the application of established construction methodologies and innovative solutions, aiming to meet society's needs with the least possible mobilization of resources (natural, energy, and financial), considering water and energy efficiency as central elements. More specifically, the goal is to reduce the inflows into public wastewater and stormwater drainage systems by changing the consumption habits of the population and collecting rainwater in impermeable areas, as well as treating greywater for non-potable reuse. In water supply systems, there is potential for energy production through microturbines that can harness the energy required for pressure control - hydrogeneration. [ABSTRACT FROM AUTHOR]

This study addresses a persistent environmental concern related to graywater discharge from households, highlighting its potential to contribute to increased pollution in water bodies. To mitigate this issue, the research explores the use of subsurface flow‐built wetlands, specifically focusing on the innovative application of constructed tidal and vertical flow wetlands (CTWFWs) as wastewater treatment systems. The study not only evaluates the efficacy of these CTWFW systems but also delves into the crucial aspects of their operation and their interactions with the biological, physical, and chemical characteristics of graywater. A key innovation of this research is the investigation of zeolite's effectiveness and the utilization of perlite‐based plant species in both mixed and monoculture configurations to develop lab‐scale hybrid constructed wetlands (HCWs). These HCWs are designed for the removal of organic matter and nutrients from graywater, offering a sustainable and cost‐effective solution to this environmental challenge. The study also examines the dynamic processes involved in graywater treatment, emphasizing how the removal of parameters like biological oxygen demand (BOD), nutrients, total suspended solids (TSS), and disinfection efficiency can significantly impact the effectiveness of treatment systems. Furthermore, the research scrutinizes the intricate relationship between the treatment unit's dimensions and the specific criteria that need to be met for efficient graywater treatment. Intriguingly, the study tracks the changes in graywater composition and the treatment process over time. By conducting on‐site measurements of various physicochemical characteristics such as temperature, dissolved oxygen (DO), electrical conductivity (EC), turbidity, total dissolved solids (TDS), and pH, the research offers a comprehensive understanding of the treatment system's performance and adaptability. The study dives into the microbial communities within the treatment systems, utilizing 16S rRNA amplicon sequencing to characterize the complex microbial ecosystem present in graywater. This approach sheds light on the interplay between microorganisms, physicochemical conditions, plant responses, substrate dynamics, and the production of microbial metabolites. It underscores the holistic nature of the research, encompassing various aspects of graywater treatment. Notably, the study explores the application of biochar in combination with the target heavy metal, cadmium (Cd), within constructed wetlands (CWs). This innovative approach aims to better understand the kinetics and isothermal adsorption of lead in the context of mouthwash residue, expanding the knowledge base in this critical area. The research findings are substantial, with remarkable removal efficiencies achieved for parameters like TSS, turbidity, chemical oxygen demand (COD), nitrate, and phosphate. These results underscore the practicality and effectiveness of the proposed treatment methods. This holistic and pioneering research significantly advances the understanding of sustainable graywater treatment, offering valuable insights and practical solutions to mitigate water pollution concerns. Practitioner Points: This study addresses a persistent environmental concern related to greywater discharge from households, highlighting its potential to contribute to increased pollution in water bodies.The study not only evaluates the efficacy of these CTWFW systems but also delves into the crucial aspects of their operation and their interactions with the biological, physical, and chemical characteristics of greywater.A key innovation of this research is the investigation of zeolite's effectiveness and the utilization of perlite‐based plant species in both mixed and monoculture configurations to develop lab‐scale hybrid constructed wetlands (HCWs). [ABSTRACT FROM AUTHOR]

Green walls are gaining attention for greywater management in the imminent terrestrial space and land constraint scenario. They have been tested primarily with greywater from a single source such as showers, hand or wash basins, laundry, and kitchen or a mix of a couple of these sources but barely with mixed greywater from all these household activities. Here, a green wall system coupled with a slow sand filter (SSF) was tested for managing household greywater. It consisted of a set of five serial hydraulic flow-connected reactors and an SSF unit. Each reactor housed an Epipremnum aureum sapling embedded in the support bed matrix, consisting of cocopeat and granular activated charcoal. The system operated at 150 cm d−1 hydraulic loading rate (HLR) achieved 90 ± 0.7%, 85 ± 4.5%, 72.9 ± 4.4%, and 60.6 ± 5.1% removal efficiencies for turbidity, chemical oxygen demand (COD), total nitrogen (TN), and total phosphorous (TP), respectively. The system maintained similar treatment performance with varying greywater strength when COD and TN were below ~400 and ~15 mg L−1, respectively. The polished effluent produced by SSF operated at 187 cm d−1 HLR, with characteristics <5 mg L−1 COD, <2 NTU turbidity, <1 mg L−1 TN, ~0.5 mg L−1 TP, ~7.8 pH, and <100 MPN per 100 ml fecal coliforms, qualifies the standards for non-potable reuse applications. Along with reclaimed water reuse, green walls provide environmental benefits by fixing CO2 in plant biomass. Overall, the low-cost system offers efficient greywater management in an eco-friendly way with minimized resource consumption and areal footprint. [ABSTRACT FROM AUTHOR]

A dynamic model, fed with time-variant inputs, of the entire water urban system, coupled with Life Cycle Assessment (LCA) and Life Cycle Costing (LCC), was developed and applied to perform water balance analysis and to assess the environmental and economic aspects of water reuse. Six scenarios using different water sources potable water, rainwater, greywater, and treated wastewater were compared for a future Model City under typical Israeli conditions. The integrated dynamic simulation-LCA-LCC approach considers demands for several water resources and their availability, contains several feedback loops in the water system, and can be applied to any case study. Finally, the combined simulation-LCA-LCC was embedded into an optimisation framework. Results indicate that using treated greywater or treated wastewater for non-potable uses were the most economical scenarios. Business-as-usual scenario, where all urban water functions use potable water, displays the largest negative environmental impacts in all categories compared to using alternative water sources. [ABSTRACT FROM AUTHOR]

To solve the upcoming environmental problems, sponge city concepts as well as new technologies are being developed these days. One of the future challenges is to reduce drinking water demand by using decentralized water recycling systems. This study aimed to investigate the performance of a specially designed pilot wetland roof (PWR) treating domestic greywater (GW) at ground level under outdoor conditions and to evaluate the effects of different hydraulic loading rates (HLRs) for a period of two years. The results showed highly efficient removal of typical greywater pollutants from the system, e.g., five-day biochemical oxygen demand (BOD5) > 96%, chemical oxygen demand (COD) > 93%, total suspended solids (TSS) >94%, anionic surfactants (AS) > 94%, ammonium-nitrogen (NH4-N) > 84%, total nitrogen (TN) > 71%, total phosphorous (TP) > 87%, and E. coli (1.86 ± 1.54 log-removal). The mean concentrations of the targeted parameters at the outflow were in compliance with the requirements for discharge to the environment and met reclaimed water quality standards for agricultural irrigation, except for E. coli. Statistically significant (p < 0.05) results of pollutant mass removal rate across different HLRs indicated the potential effect of HLR on treatment performance, and HLR in a range of 67–80 L m–2 d–1 contributed to a higher removal efficiency without compromising the limit values. A comparatively low HLR of 45 L m–2 d–1 should be applicable if pathogen removal is the most important requirement. Plant species showed good plant vitality and adapted well to the water storage mat. The higher the mean ambient air temperature, the greater runoff reduction (>50%) was observed due to high evapotranspiration. The results showed the system is a promising green technology for GW recycling and can be scaled up for application to urban buildings. [ABSTRACT FROM AUTHOR]

One of the innovative approaches to supplying water demands for irrigation and recreational purposes is the treatment and reuse of greywater. However, during the coronavirus pandemic, greywater has the potential to be polluted by SARS-CoV-2. Therefore, it is unsafe to reuse it during the peak of the COVID-19 outbreak. In this research, a membrane bioreactor combined with an ultraviolet disinfection system is applied to treat the greywater and remove the SARS-CoV-2 virus up to the required quality for irrigation or flush tank purposes. The results showed membrane bioreactor could remove 94.3 ± 1.2% of initial chemical oxygen demand and be partially successful in virus removal. Fifty percent of secondary treated effluent samples were still positive for SARS-CoV-2 RNA. The results also illustrated that ultraviolet disinfection could reduce faecal and total coliform by more than 99% and eliminate the SARS-CoV-2 virus. The tertiary treated effluent biochemical oxygen demand, chemical oxygen demand, and total coliform were 1.7 ± 0.2 mg/l, 18 ± 1.2 mg/l, and below 3 MPN/100 mL, respectively. Moreover, all of the samples of the tertiary treated effluent were negative for coronavirus RNA. Therefore, the tertiary treated effluent characteristic satisfied Iran's standards for wastewater reuse in irrigation. [ABSTRACT FROM AUTHOR]

The aim of the paper was to identify factors that influence the public perception of the possibility of replacing tap water with rainwater or greywater. In order to check whether a geographical location and water resources of a region affect the public's attitude toward alternative water systems, the surveys were carried out among respondents from twelve countries. The surveys identified the level of awareness among respondents about their country's water resources, ways to save water at home, and their attitudes to rainwater and greywater as additional sources of water in a building. The results showed that only 39% of respondents would not be afraid to use treated greywater in their household. The situation was better in case of replacement of tap water with rainwater, where more than 54% of the respondents were not concerned. The use of alternative sources of water for body washing and cleaning works was the biggest concern among the respondents. In case of greywater recycling, this was indicated by 56% (personal hygiene) and 34% (cleaning works) of respondents. People in the countries with low water resources view alternative water sources more favourably. They are also more aware of, and more likely to accept the use of rainwater or greywater even in uses where they will come into contact with the human body. The research also showed that for more than 3/4 of respondents, funding to install these systems would encourage their use in their household. [ABSTRACT FROM AUTHOR]

To achieve Goal 6 of the 2030 Agenda for Sustainable Development and provide water for all, water reuse is essential. We assessed the potential of treating greywater (LGw) while reusing it via irrigation of Canna x generalis, commonly used in nature-based solutions (NBS), with a view on plant development. The study was conducted at a mesocosm scale with factorial designs to test two substrates and four types of irrigation water. Stage 1 tested LGw, LGw with nutrients (LGw + N), tap water (TW) and TW + N. Stage 2 tested indoor and outdoor applications of TW (TWi and TWo, respectively) and LGw (LGwi and LGwo, respectively). All treatments resulted in reductions in total nitrogen and phosphate concentrations. The effluent turbidity, chemical oxygen demand, and surfactant contents of LGw + N and LGw decreased considerably after passing through the substrate. The results showed no statistical differences among the measured variables when LGw and TW received commercial fertilizers, which provided advantageous conditions for complete plant development, as evidenced by flowering. Conversely, compared with all other treatments, LGw treatment alone resulted in inferior development and exhibited some symptoms of nutritional deficiency, observed as reductions in dry biomass in the aboveground parts (range: 1.87–6.52 g) and belowground parts (10.03–36.19 g). Overall, Canna x generalis did not exhibit symptoms of toxicity and became fully developed, except for flowering, proving to be a robust species that is resistant to adverse environmental conditions, and is therefore recommended for cultivation in nature-based systems for landscaping integrated with LGw treatment and reuse. [ABSTRACT FROM AUTHOR]

Significant amounts of waste heat are deposited in greywater, which can be utilized, among other things, for heating domestic hot water in residential buildings. The manuscript presents an economic analysis of a greywater heat recovery system using a vertical heat exchanger of the "tube-in-tube" type in a single-family building. The analysis is based on the results of experimental research on the energy efficiency of three domestic hot water preparation systems equipped with a vertical heat exchange unit. The analyzed systems had different concepts for the flow of preheated water and cold water. The research showed that the implementation of a vertical "tube-in-tube" heat exchanger can reduce the energy consumption for domestic hot water preparation by approximately 45.7% to 60.8%, depending on the system variant. Furthermore, it was determined that the energy savings associated with reducing domestic hot water consumption can cover the investment costs related to the purchase and system of the heat exchanger within a period of 2 to 5 years of system operation, depending on the design variant and the unit price of electricity. [ABSTRACT FROM AUTHOR]