Partially water-level-fluctuating strategy enhances rural greywater treatment in vertical flow constructed wetlands.

Assessing the environmental impact of wastewater leakage: A case study on grey water and carbon footprints in wastewater collection networks

Performance evaluation of various growing media in vertical green wall for greywater treatment in hyper-arid climate

Grey water footprint in the context of climate change and sustainable development: A global bibliometric analysis

Assessment of combined nutrients and pesticides grey water footprint in a sub-Saharan African lake catchment

Ageing process characterization of innovative substrates in vertical-flow constructed wetlands after treating greywater.

Productive and physiological response of Pereskia grandifolia Haw. irrigation deficit with grey and brackish water in the Brazilian Semiarid Region

A sustained outbreak of H5N1 influenza virus among wild fowl and domestic livestock has caused more than 70 zoonotic infections in humans in North America, including two deaths. The United States Centers for Disease Control and Prevention has recommended rapid H5 subtyping for all hospitalized cases with influenza A virus infection to enable prompt initiation of antiviral treatment, as well as infection prevention and implementation of public health measures to control spread. To address these needs, we developed a qualitative multiplex RT-qPCR assay to subtype H5 influenza virus in nasal, nasopharyngeal, and conjunctival specimens with a limit of detection of 250 copies/mL. No cross-reactivity was observed with other common respiratory viruses, including seasonal H3N2 and H1N1 influenza A viruses. We retrospectively subtyped 590 influenza A virus-positive clinical specimens with Ct values less than 31 processed by University of Washington labs between March 2024 and February 2025, including 512 specimens collected during the 2024-2025 influenza season, and detected no H5 positives. After clinical implementation, we performed 150 clinically ordered H5 subtyping tests between February and April 2025 and again detected no positives. This work enhances clinical pandemic preparedness activities and highlights the exceedingly low prevalence of H5N1 influenza virus during the 2024-2025 respiratory season.IMPORTANCEThe spread of H5N1 influenza virus in the United States has led to the culling of almost 200 million birds, infected cow herds across 17 states, and resulted in 70 human infections as of July 2025. Rapid PCR subtyping of H5 influenza virus is critical to inform hospital infection prevention and public health to enable containment of viral transmission. Here, we report the design, validation, and clinical implementation of a qualitative multiplex H5-subtyping RT-qPCR assay for nasopharyngeal, nasal, and conjunctival swab specimens. Additionally, we offer the largest reported study of H5 subtyping of influenza A virus-positive specimens in the United States to date. No H5 infections were detected in 740 samples collected between March 2024 and April 2025 from patients with confirmed influenza A virus infection in a large academic medical system in Seattle, WA.

Abstract Climate change is a global concern due to its significant impact on water resources, leading to increased hydro-climatic extremes such as droughts, floods, and high temperatures. Consequently, the reuse of greywater for irrigation has gained popularity in recent decades, alongside advancements in treatment methods. It serves as an alternative water conservation strategy that can help preserve existing freshwater bodies as shifting rainfall patterns affect water availability. Numerous studies have investigated the effects of greywater irrigation on crop growth, development, and quality. Research findings indicate that greywater irrigation can have both positive and negative impacts on postharvest crop quality, highlighting the need for proper treatment to reduce heavy metal content and microbial loads. Reusing greywater can alleviate the demand for clean water, thereby reducing pressure on clean water resources. Given the increasing scarcity of clean water, this paper aims to examine the impacts and benefits of greywater reuse for both potable water conservation and the agricultural sector. We present a narrative review of research on greywater irrigation and its effects on crop development, productivity, and product quality. Additionally, we assess the legal implications, environmental concerns, and public perceptions associated with greywater use. Some countries have implemented guidelines and policies to ensure the safe reuse of greywater, thereby promoting water recycling and conservation. Furthermore, we explore the feasibility of using locally available, low-cost greywater treatment alternatives and identify existing knowledge gaps, offering recommendations to ensure the safe and effective use of greywater.

Abstract The United States (U.S.) is a major beef producing and consuming country and increasing demand for beef is expected to apply additional pressure on non-renewable water resources. Water footprints of beef production are widely documented in the literature and are a contentious issue. The sustainability of water use in beef production is typically assessed through virtual water footprints (VWF) and life cycle assessments (LCAs). However, ongoing debates persist regarding whether water footprints should be volumetric or impact-based assessments. Distinct differences in the methodologies of VWF and LCA introduce challenges for policymakers who aim to redistribute water resources along the beef supply chain to improve sustainability. Here, we summarize the challenges and opportunities associated with water use in the U.S. beef supply chain by synthesizing findings from 71 studies spanning multiple disciplines, including geology, hydrology, water resources, sustainability, livestock production, economics, and policy from 1993 to 2024. The primary challenge identified was the lack of comparability between VWF and LCA studies. Inconsistencies in accounting for green, blue, and grey water footprints, varying functional units, and different system boundaries complicate across-study comparisons. The discrepancies observed between studies are often related to data deficiencies, requiring the implementation of some generalized assumptions. Furthermore, VWF tends to quantify water footprints on a regional or national basis, while LCAs are usually conducted locally. Consequently, resource management initiatives informed by regional-level figures may not have the desired effect on mitigating local water resource stressors. An essential step in addressing these challenges is improved data collection in the form of standardized methodology, functional units, and system boundaries to ensure targeted and meaningful data acquisition. An additional opportunity to address some of the data deficiencies is technology adoption. For example, on-farm camera sensors or stand-alone water monitoring devices can measure direct water consumption. Additionally, the installation of real-time water flow monitoring systems in beef processing plants has the potential to reduce water footprint through improved plant management. The adoption of technologies such as remote sensing and improved irrigation applicators has reduced the water footprint of crop production and, subsequently, the beef water footprint as well due to the impact of irrigation on cattle feed footprints. Continued improvements in water use efficiency and management through technology adoption, as well as the implementation of standardized methods for assessing water footprints, are critical for generating comparable data that can inform policy-making decisions in the U.S. beef industry.

Biological treatment of greywater serves as a sustainable and effective solution for managing water resources, playing a vital role in addressing the challenges posed by climate change. With the growing population and increasing demand for water, the reuse of greywater as a valuable resource has garnered more attention. This research examines various methods and techniques of biological treatment of greywater and analyzes its benefits and challenges. The results indicate that biological treatment can help reduce pollution, improve water quality, and conserve water resources. Furthermore, this process leads to a decrease in the costs of treatment and distribution of water and enhances community resilience to climate change. By providing suggestions for developing supportive policies, education and awareness-raising, research and development, and international cooperation, this article emphasizes the importance of biological treatment of greywater in creating a sustainable and resilient future against climate change.

Urbanization and climate change significantly worsen water quality and quantity issues, heightening the urgency to address the foregoing concerns in relation to sustainable urban water management. Water Footprint Accounting (WFA) provides a novel and holistic lens for urban water management by quantifying blue, green, and gray water footprints. Unlike conventional assessments that focus only on withdrawals, WFA captures both consumption and pollution, offering a more integrated view of sustainability. This study applies WFA to the University of the Philippines—Diliman campus, using adapted numerical methods from established literature. The approach highlights hidden water dependencies, identifies critical hotspots, and demonstrates the potential of WFA as a decision-support tool for building water-resilient campus. A modified WFA spreadsheet tool was developed to automate the calculation of the blue, green, and gray water, which was then used for UP Diliman. The calculated water footprint (WF) of UP Diliman was mapped, revealing a spatial representation of the WF and WF hotspots. The results revealed that the highest total footprint was the gray water footprint (WF) of stormwater, amounting to 146,048,674 m3/year, primarily associated with suspended solids from eroded ground surfaces during rainfall events. In contrast, the lowest footprint was the blue WF of rainwater at 1,240,989 m3/year. Spatial mapping of water footprints revealed hotspots that serve as indicators of urban characteristics: blue and gray WF hotspots in highly developed areas, and green WF hotspots in zones with significant evapotranspiration. These insights highlight hidden water dependencies, identify critical pressure points, and underscore the need for future developments to integrate water-saving technologies and Low Impact Development (LID) practices. Overall, this study demonstrates how WFA can be applied as an evidence-based decision-support tool for managing and improving urban water systems in mixed land-use settings.

Grey water and carbon footprint of textile industry: A case study

Efficiency of multi-layer greywater and rainwater treatment for sustainable water management through water reuse in irrigation

How do production practices and climate change impact the water footprint of dairy farms?

Constructed wetlands (CWs) offer an eco-friendly wastewater treatment technology which can provide a low-cost alternative to “raw wastewater discharge” which although is increasingly becoming unsustainable, remains the most common practice for urban housing colonies in India. This study demonstrates that despite being a semi-engineered system CWs can provide consistent removal efficiency while treating “grey water”, which constitutes the major fraction of the total wastewater generated in an urban housing colony. The lack of field-scale performance data for CWs has kept builders, practicing engineers, and policy makers thus far unconvinced about their true potential beyond scientific publications. The work presented here provides comparative assessment of phytoremediation potential of two macrophytes Canna indica and Ageratum conyzoides while treating grey water emanating from a nearby urban housing colony. How the relative positioning of these macrophytes, upstream or downstream of each other, can influence the wastewater treatment efficiency was also evaluated. Higher removal efficiencies were observed for inorganic nitrogen (43.4%) and phosphate (45.68%) for CWs vegetated with Canna indica while higher sulfate removal efficiency (63.5%) was observed for CWs vegetated with Ageratum conyzoides. For chemical oxygen demand (COD) and total suspended solids (TSSs), removal efficiencies remained consistently above 65% and 80%, respectively.

This study investigates the operational performance and optimization of a real greywater treatment system utilizing aluminum (Al)-based electrocoagulation (EC). The EC process was systematically evaluated and optimized through Response Surface Methodology (RSM) using the Box–Behnken Design (BBD), focusing on three critical parameters: pH, current density, and electrolysis time. Greywater samples collected from domestic sources were characterized by key physicochemical parameters including pH, COD, TSS, turbidity-ty, and electrical conductivity. The electrochemical treatment was conducted using a batch reactor equipped with Al electrodes in a monopolar configuration. Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), X-ray Diffraction (XRD), and Fourier-Transform Infrared Spectroscopy (FTIR) were employed to characterize both the electrodes and the generated sludge. Results revealed a maximum COD removal efficiency of 86.34% under optimized conditions, with current density being the most influential factor, followed by its significant interaction with pH. The developed quadratic model exhibited high predictive accuracy (R2 = 0.96) and revealed significant nonlinear and interaction effects among the parameters. Sludge characterization confirmed the presence of amorphous aluminum hydroxide and oxyhydroxide phases, indicating effective coagulant generation and pollutant capture. The treated greywater met physicochemical criteria for non-potable reuse, such as agricultural irrigation, supporting resource recovery objectives. These findings demonstrate that EC is a low-waste, chemically efficient, and scalable process for decentralized wastewater treatment, aligning with the goals of sustainable chemical engineering.

Due to climate change, population increase, and urbanization, freshwater resources are getting depleted. This means that we need to find sustainable ways to conserve water. Greywater, which makes up as much as 75% of household wastewater, can be reused for non-potable purposes if it is treated correctly. This study examines the efficacy of plantain peels activated carbon (PPAC) in the treatment of greywater by adsorption. Plantain peels, an agricultural byproduct, were carbonized and chemically activated with phosphoric acid (H₃PO₄), potassium hydroxide (KOH), and zinc chloride (ZnCl₂) to create PPAC. Batch adsorption tests were used to see how well we could get rid of some contaminants such total dissolved solids (TDS),electrical conductivity (EC), turbidity, and pH. The results showed that the treatment significantly improved the water quality. The pH went from acidic (3.52–4.17) to nearneutral levels (4.79-7.53), the electrical conductivity (EC) went from 5.52–6.15 µS/cm to 4.48–4.97 µS/cm, and the total dissolved solids (TDS) reduced from 20.4–30.3 mg/L to 2.49–3.27 mg/L. An ANOVA comparing the control and PPAC treatment of greywater indicates no significant difference in the treatment means for pH. Furthermore, ANOVA indicated that the Fcalculated value exceeds the Fcritical value, and the P value is less than 0.05 at a 95% confidence level for EC, TDS and salinity, indicating that there was significant difference in treatment means. Even though the salinity increased (from 0.2–0.4 ppt to 0.5–0.9 ppt), it was still within safe levels. The results show that PPAC is a cheap, eco-friendly, and effective adsorbent that can greatly improve the quality of greywater. The report advocates for the implementation of decentralized, sustainable water treatment systems, especially in resourcelimited regions, while encouraging waste-toresource initiatives.

A comprehensive review of treatment technologies for greywater contaminants: an emphasis on surfactants.

Cultivation of blitum (<i>Amaranthus blitum</i>) in hydroponic and aeroponic systems intended for cultivation under netting on building rooftops for urban food production using grey water for irrigation