Search Results (68)

Climate change is significantly affecting water availability, emphasising the need for sustainable strategies such as wastewater reuse. While this represents a promising alternative resource, insufficiently treated wastewater may pose health risks, particularly through aerosol formation during irrigation, which can facilitate Legionella transmission. This study aimed to evaluate the presence of Legionella across various stages in a wastewater treatment plant (WWTP) that reuses effluent for agricultural purposes. Samples from the influent, four treatment phases, and the final effluent were analysed using both culture-based methods and quantitative PCR (qPCR) for Legionella spp. and L. pneumophila. qPCR detected Legionella spp. in all samples and L. pneumophila in 66% of them. In contrast, the culture-based analysis showed much lower detection levels, with only one positive sample at the influent stage—likely due to microbial interference or growth inhibition. Although contamination decreased in the final effluent, Legionella was still detected in water designated for reuse (Legionella spp. in 100% and L. pneumophila in 17% of samples). No treatment stage appeared to promote Legionella proliferation, likely due to WWTP characteristics, in addition to wastewater temperature and COD. These findings underscore the importance of monitoring Legionella in reclaimed water and developing effective control strategies to ensure the safe reuse of treated wastewater in agriculture. Full article

Ozonation has been promoted as a successful methodology for recovering effluents from wastewater treatment plants, with special emphasis on wastewater contaminated with pharmaceutical and personal care products (PPCPs). Still, ozonation reactions may generate potentially toxic by-products, jeopardizing human health safety, a critical aspect considering the use of reclaimed water. We aimed at understanding the potential impacts of ozonation on the quality of reclaimed water for human use through cell viability assays with human skin keratinocytes (HaCaT cell line). Under this context, the cytotoxicity of synthetic effluents contaminated with methyl- and propylparaben, paracetamol, sulfamethoxazole, and carbamazepine, both individually and in mixtures, was assessed before and after ozonation. The viability of HaCaT cells decreased after exposure to untreated synthetic effluents, denoting the cytotoxicity of the tested PPCPs singly and more prominently in mixtures (especially in those combining two and three PPCPs). A similar pattern was observed when testing effluents treated with ozonation. Since the parent contaminants were fully removed during ozonation, the observed cytotoxicity relates to degradation by-products and interactive effects among them. This study suggests that ozonation is poorly efficient in reducing cytotoxicity, as required for the safe use of ozone-treated reclaimed water in activities involving direct contact with human skin. Full article

With water availability being one of the world’s major challenges, this study aims to propose a Zero Liquid Discharge (ZLD) system for treating saline effluents from an urban wastewater treatment plant (UWWTP), thereby supplementing into the existing water cycle. The system, which employs membrane (nanofiltration and reverse osmosis) and thermal technologies (multi-effect distillation evaporator and vacuum crystallizer), has been installed and operated in Cyprus at Larnaca’s WWTP, for the desalination of the tertiary treated water, producing high-quality reclaimed water. The nanofiltration (NF) unit at the plant operated with an inflow concentration ranging from 2500 to 3000 ppm. The performance of the installed NF90-4040 membranes was evaluated based on permeability and flux. Among two NF operation series, the second—operating at 75–85% recovery and 2500 mg/L TDS—showed improved membrane performance, with stable permeability (7.32 × 10⁻¹⁰ to 7.77 × 10⁻¹⁰ m·s⁻¹·Pa⁻¹) and flux (6.34 × 10⁻⁴ to 6.67 × 10⁻⁴ m/s). The optimal NF operating rate was 75% recovery, which achieved high divalent ion rejection (more than 99.5%). The reverse osmosis (RO) unit operated in a two-pass configuration, achieving water recoveries of 90–94% in the first pass and 76–84% in the second. This setup resulted in high rejection rates of approximately 99.99% for all major ions (Cl⁻, Na⁺, Ca²⁺, and Mg²⁺), reducing the permeate total dissolved solids (TDS) to below 35 mg/L. The installed multi-effect distillation (MED) unit operated under vacuum and under various inflow and steady-state conditions, achieving over 60% water recovery and producing high-quality distillate water (TDS < 12 mg/L). The vacuum crystallizer (VC) further concentrated the MED concentrate stream (MEDC) and the NF concentrate stream (NFC) flows, resulting in distilled water and recovered salts. The MEDC process produced salts with a purity of up to 81% NaCl., while the NFC stream produced mixed salts containing approximately 46% calcium salts (mainly as sulfates and chlorides), 13% magnesium salts (mainly as sulfates and chlorides), and 38% sodium salts. Overall, the ZLD system consumed 12 kWh/m³, with thermal units accounting for around 86% of this usage. The RO unit proved to be the most energy-efficient component, contributing 71% of the total water recovery. Full article

The growing challenges of freshwater scarcity and the high generation of agro-industrial waste, particularly from fruit and vegetable (F&V) processing, pose significant threats to the sustainability of global food systems. F&V waste, which represents a major portion of the 1.3 billion tons of annual food waste, is characterized by a high moisture content (80–95%), making it a largely overlooked but promising source of water recovery. This review critically assesses the techno-economic and environmental feasibility of extracting water from moisture-rich agro-industrial waste streams. Potential technologies such as solar distillation and membrane separation are evaluated to determine their capacity to treat complex organic effluents and recover high-quality water. The potential end uses of reclaimed water in all sectors are explored, focusing on agricultural irrigation, fertigation, industrial reuse and environmental restoration. This study addresses a key research gap and proposes the reclassification of agro-industrial waste as a viable water resource aligned with circular bioeconomy principles and Sustainable Development Goals (SDGs) 6 and 12. Full article

Palm oil mill effluent (POME), a byproduct of palm oil processing, has substantial resource recovery potential. Its rich biodegradable content supports methane (CH₄) production via anaerobic digestion, enabling renewable energy generation. Additionally, the significant water content of POME can be reclaimed for use in boiler feed, irrigation, and drinking water. However, selecting appropriate technologies to recover valuable resources from POME is challenging, particularly for the purification and upgrading of biogas. Membrane technologies offer an effective approach for transforming POME treatment from an energy-intensive process into a resource recovery system, supporting the decarbonization of palm oil production and advancing global sustainability objectives. This technique is cost-effective and ecofriendly for biogas purification and water reclamation. For biogas purification and upgrading, membrane systems offer the lowest capital and operational costs at 5.654 USD/m³, compared to other technologies, such as 6.249 USD/m³ for water scrubbers and 6.999 USD/m³ for chemical absorbers. This review primarily explores the potential of membranes for gas purification from POME and examines their integration with other processes to develop advanced systems, such as ultrasonicated membrane anaerobic systems and membrane anaerobic systems, to enhance biogas production. In addition, water reclamation from POME is discussed, with ultrafiltration membranes emerging as the most promising candidates. Proton exchange membranes, such as Nafion, are used extensively in microbial fuel cells to improve electricity generation, and this is also summarized. Finally, challenges and future perspectives are highlighted, emphasizing the broader potential of membrane technology in POME wastewater resource recovery. Full article

Water scarcity has driven the use of wastewater treatment plant (WWTP) effluents as reclaimed water, highlighting the need to overcome challenges such as the presence of emerging contaminants, particularly microplastics (MPs), which WWTPs are unable to effectively remove. Membrane-based processes, such as microfiltration, have demonstrated high efficiency in the removal of suspended solids, and their application for MP removal is currently under investigation. This study assesses the influence of microfiltration membrane spacer size (1 mil and 80 mil) and geometry—diamond and corrugated—on MP recovery performance, using synthetic wastewaters with varying MPs concentrations. The results indicate the superior performance of large corrugated and small diamond-shaped membranes, as both exhibited the highest and comparable permeate flux, with no MP retention within the membrane element. All microfiltration membranes achieved an 80% recovery of the influent as safe reclaimed water and demonstrated an MP recovery efficiency exceeding 99%, with 100% rejection for fragments and up to 98% rejection for fibres. Full article

The reuse of reclaimed water is essential for sustainable water management in arid regions. However, despite advancements in Wastewater Treatment Plants (WWTPs), certain micropollutants may persist. To address these challenges, the recently enacted European Urban Wastewater Treatment Directive (UWWTD) has established strict standards focused on monitoring twelve specific indicator compounds. In line with this, the present study aims to evaluate the concentrations and potential risks of these twelve UWWTD-designated compounds across various water sources, including surface water, groundwater, and effluents from a WWTP in the southeast of Spain. Although none of the evaluated water sources are, as expected, intended for human consumption, risks were assessed based on worst-case scenarios that could amplify their impact. The study assessed potential risks to human health across different age groups and ecosystems, focusing on key organisms such as fish, daphnia, and algae, using empirical assessment approaches. The risk assessment identified a low risk for most compounds regarding human health, except for citalopram (HRQ = 19.116) and irbesartan (HRQ = 1.104), which showed high human risk quotients (HQR > 1) in babies, particularly in reclaimed water. In terms of ecotoxicological risk, irbesartan presented the highest ecological risk quotient (ERQ = 3.500) in fish, followed by clarithromycin, with algae (ERQ = 1.500) being the most vulnerable organism. Furthermore, compounds like citalopram, venlafaxine, and benzotriazole exhibited moderate ecological risks (ERQ between 0.1 and 1) in the reclaimed water, and their risk was reduced in surface water and groundwater. Finally, this study discussed the potential impacts of elevated concentrations of these emerging compounds, emphasizing the need for rigorous wastewater monitoring to protect human health and ecosystem integrity. It also revealed notable differences in risk assessment outcomes when comparing two distinct evaluation approaches, further highlighting the complexities of accurately assessing these risks. Full article

Wastewater is a sustainable water supply which uses reclamation and reuse processes to protect freshwater resources. Biochar application is considered an efficient and low-cost wastewater reclamation and reuse technique in recent years. From this perspective, this paper mainly aimed to obtain reclaimed water using biochar application, with an aim of contributing to a circular economy. The major aim of this study was to assess the quality and reuse potential of treated water through the biochar adsorption process. The assessment was based on the EU (741/2020) wastewater reuse legislation. Turbidity, Biological Oxygen Demand (BOD₅), Total Suspended Solid (TSS), and E. coli analyses were performed to determine the effluent quality. In the end of the biochar adsorption process, a Class B reclaimed water quality according to EU legislation was obtained. This study validated that malt-dust-derived biochar is an efficient and low-cost adsorbent and can achieve a high quality of reclaimed water. An average reduction of 31.3% in operational costs was reported compared to an activated sludge system. Full article

This paper aimed to determine the quality of reclaimed water using biochar. Turbidity, biological oxygen demand (BOD₅), total suspended solid (TSS), and E. coli analyses were performed to determine the effluent’s quality. At the end of the treatment, the water reclaimed from greywater met the requirements of Class B quality according to European Union (EU) legislation. This study verified that malt dust-derived biochar is an efficient and low-cost adsorbent that can be used to obtain reclaimed water. The reclaimed water was used for the irrigation of the green areas of Osmanbey Campus in Turkey. It was reported that on average %30 of water consumption was prevented by water reuse. Full article

The classified water pricing system is an effective measure for promoting the rational utilization of water resources under market mechanisms. Studying the water prices of three different types of water sources, including reservoir water, river water, and wastewater treatment plant effluent, is the basis for promoting the use of reclaimed water. However, there remains a spectrum of viewpoints on how to establish a pricing mechanism for reclaimed water at present. This study primarily focuses on the multi-level quality-separated water supply system in Yiwu City, China. It analyzes the limitations of the current water pricing formation mechanism and the externality of integrating reclaimed water into the unified allocation of multiple water sources. Based on the principles of full-cost water pricing and externality theory, a supply-side classified water pricing permit cost and pricing calculation model, covering the entire process of the social water cycle, is proposed. It focuses on the analysis of the impact of equity costs and environmental costs on supply-side classified water pricing. The Shapley value method is used for the technology of cost allocation among stakeholders to reasonably distribute the calculated water pricing of reclaimed water. The price of reclaimed water varies depending on the user type, with residential users paying 2.93 CNY/t, industrial users 4.00 CNY/t, and government allocations at 8.52 CNY/t. Compared with the classified water prices of various stakeholders on the user side of reservoir water, reclaimed water has a significant price advantage. This research demonstrates that the supply-side classified water pricing model, which includes a permit cost and pricing calculation framework, can encourage the supply of higher-quality water at corresponding higher prices, while also providing the internalization of external costs. Furthermore, the Shapley value method of cost allocation can realize the fair burden of stakeholders on the calculated water price and maintain the competitive advantage of reclaimed water prices. Full article

Here we report on preliminary efforts to assess the potential to use reclaimed water from municipal wastewater treatment plants for irrigation of vineyards in Napa Valley, California, USA and Valle de Guadalupe, Baja California, Mexico. Vineyards in Napa Valley use a range of source waters including 70 L/s of reclaimed water during the summertime irrigation season. Reclaimed water is secondary effluent that undergoes filtration and disinfection and meets stringent total coliform (<240 MPN/100 mL) and turbidity (10 NTU) requirements. Vineyards in Valle de Guadalupe currently use regional groundwater supplies of marginal quality, and there is interest in expanding source waters to include reclaimed water from nearby Ensenada or the more remote Tijuana. Valle de Guadalupe is drier than Napa Valley and has ongoing salinity management challenges, making the region more sensitive to using reclaimed water for irrigation. Several social and economic factors facilitated the implementation of reclaimed water reuse in Napa Valley for vineyard irrigation, including (1) formation of an assessment district by interested growers to help finance pipeline construction, (2) a long-term reclaimed water vineyard irrigation study by agricultural experts that confirmed the reclaimed water was safe, and (3) a well-defined and relatively low unit cost of reclaimed water. In Valle de Guadalupe, the federal government has approved a project to transport 1000 L/s of reclaimed water over 100 km from Tijuana to Valle de Guadalupe. Questions remain including financing of the project, reclaimed water quality, grower interest in using reclaimed water, and community concerns for such a large-scale program. In considering reclaimed water reuse in vineyards, a key issue is implementation of long-term studies showing that reclaimed water is effectively treated and is safe for irrigation, especially from the standpoint of salt content. In addition, the cost of reclaimed water needs to be comparable with traditional water sources. Finally, in addition to assessing economic constraints, social constraints and water user concerns should be comprehensively addressed in the context of a regional integrated water management framework. Full article

Many pharmaceuticals (PhMs), compounds for the treatment or prevention of diseases in humans and animals, have been identified as pollutants of emerging concern (PECs) due to their wide environmental distribution and potential adverse impact on nontarget organisms and populations. They are often found at significant levels in soils due to the continuous release of effluent and sludge from wastewater treatment plants (WWTPs), the release of which occurs much faster than the removal of PhMs. Although they are generally present at low environmental concentrations, conventional wastewater treatment cannot successfully remove PhMs from influent streams or biosolids. In addition, the soil application of animal manure can result in the pollution of soil, surface water, and groundwater with PhMs through surface runoff and leaching. In arid and semiarid regions, irrigation with reclaimed wastewater and the soil application of biosolids are usual agricultural practices, resulting in the distribution of a wide number of PhMs in agricultural soils. The ability to accurately study the fate of PhMs in soils is critical for careful risk evaluation associated with wastewater reuse or biosolid return to the environment. The behavior and fate of PhMs in soils are determined by a number of processes, including adsorption/desorption (accumulation) to soil colloids, biotic (biodegradation) and abiotic (chemical and photochemical degradation) degradation, and transfer (movement) through the soil profile. The sorption/desorption of PhMs in soils is the main determinant of the amount of organic chemicals taken up by plant roots. The magnitude of this process depends on several factors, such as crop type, the physicochemical properties of the compound, environmental properties, and soil–plant characteristics. PhMs are assumed to be readily bioavailable in soil solutions for uptake by plants, and such solutions act as carriers to transport PhMs into plants. Determining microbial responses under exposure conditions can assist in elucidating the impact of PhMs on soil microbial activity and community size. For all of the above reasons, soil remediation is critical when soil pollutants threaten the environment. Full article

Sand media filters are especially recommended to prevent emitter clogging with loaded irrigation waters, but their performances rely on backwashing. Despite backwashing being a basic procedure needed to restore the initial filtration capacity, there is a lack of information about the solid removal efficiency along the media bed depth. An experimental filter with a 200 mm silica sand bed height was used to assess the effect of two operation velocities (30/45 and 60/75 (filtration/backwashing) m h⁻¹) and two clogging particles (inorganic sand dust and organic from a reclaimed effluent) on the efficiency of backwashing for removing the total suspended solids retained in different media bed slices. The average solid removal backwashing efficiency was greater with organic particles (78%) than with inorganic ones (64%), reaching its maximum at a 5–15 mm bed depth. A higher operation velocity increased the solid removal efficiency by 16%, using organic particles, but no significant differences were observed with inorganic particles. The removal efficiencies across the media bed were more uniform with organic particles (63–89%) than with inorganic (40–85%), which makes it not advisable to reduce the media height when reclaimed effluents are used. This study may contribute to future improvements in sand media filter design and management. Full article

Since urbanization poses risks to regional environments, assessing and mitigating these risks is a challenge inherent to the urbanization process. The present study employs an adapted methodology based on the water environmental capacity (WEC) to assess the risks associated with the water environment in an urbanizing area located in a valley of the Chongqing municipality in Southwestern China, with a particular emphasis on its representative regional river. By utilizing hydrological data and planned parameters specific to this region, this study estimates the spatial and temporal distribution of the WEC and pollution loads in the river under various urbanization scenarios. It also explores the potential of the utilization of reclaimed water to mitigate these water environmental risks. The results indicate that the extent of urbanization exerts significant influences on the water environment and, therefore, requires meticulous planning. Areas experiencing higher levels of urbanization in the middle reaches of the river are associated with greater environmental risks compared to those observed in the lower reaches, while minimal risk is observed in the headwater. Due to the pollution loads brought about by precipitation, there is a higher level of environmental risk during the wet season (May–October) compared to the dry season. Utilizing reclaimed water can effectively reduce the pollution loads discharged into the river and is the most efficient means of mitigating environmental risks. To effectively manage environmental risks during urbanization in this valley area, further studies should prioritize examining the correlation between the scale of urban expansion and the river’s environmental carrying capacity. Additionally, it is imperative to establish realistic targets for the river water’s quality and discharge standards for the effluent from wastewater treatment plants. Furthermore, it is crucial to determine an appropriate level of utilization of reclaimed water and delve into the mechanisms behind the method used to assess the water environmental capacity. Despite these challenges, analyzing the spatial and temporal distribution of risk during urbanization and evaluating the mitigative effect of utilizing reclaimed water based on adapted assessments of the water environmental capacity hold reference value for the formulation of environmental management strategies and environmental planning. There is significant potential for this approach to have various applications. Full article

Organic micropollutants (OMPs) present in water and wastewater are in the spotlight because of their potentially harmful effects even at low concentrations and the difficulties of their elimination in urban wastewater treatment plants (UWWTPs). This study explores the impact of some membrane filtration processes on the removal of a group of 11 OMPs with an eye on the effects of two pretreatments (i.e., coagulation and adsorption onto powdered activated carbon (PAC)) and the adsorption of OMPs onto the membranes on the overall removal. For this purpose, ultrafiltration (UF) and nanofiltration (NF) experiments were conducted with selected OMPs spiked in ultrapure water and secondary effluents from UWWTPs. It was observed that the adsorption of OMPs onto the membranes was influenced by the characteristics of the membranes, as well as the presence of effluent organic matter (EfOM). Since adsorption was the dominant mechanism for the rejection of OMPs by UF membranes, a study of the adsorption equilibrium of the micropollutants using UF membrane pieces as the adsorbent was conducted. The adsorption isotherms for the most hydrophobic OMPs fitted the Langmuir model. The efficiency of coagulation and powdered activated carbon (PAC) adsorption coupled with UF were also investigated. Both pretreatments alleviated membrane fouling and improved the rejection of organic and inorganic matter. The PAC pretreatment significantly improved the removal of OMPs in the combined PAC/UF process. The best options for achieving reclaimed water with satisfactory physicochemical quality, nearly devoid of OMPs and microorganisms, and suitable for diverse reuse purposes are either the NF treatment or the combination of PAC/UF. Full article