Can water reuse save the Colorado?

University of California, Los Angeles (UCLA) | April 2nd, 2025

To assess the current state of water recycling across the Colorado River Basin and its affected states, UCLA Institute of the Environment and Sustainability, in partnersh

To assess the current state of water recycling across the Colorado River Basin and its affected states, UCLA Institute of the Environment and Sustainability, in partnership with Natural Resources Defense Council, has investigated water recycling progress and policy development across the seven states in the basin.

Characterizing pyrethroid and fipronil concentrations in biosolids

Science of the Total Environment (Elsevier) | February 28th, 2025

Pesticides are prevalent in wastewater, yet few studies have measured pesticides in biosolids and aqueous media from samples collected concurrently. Seventeen California

Pesticides are prevalent in wastewater, yet few studies have measured pesticides in biosolids and aqueous media from samples collected concurrently. Seventeen California wastewater treatment plants (WWTPs) were sampled in May 2020. Biosolids samples were analyzed for 27 analytes, and paired aqueous samples (influent and effluent) were analyzed for 23 analytes. Analytes included fipronil and its transformation products (fiproles), pyrethroids, novaluron, and several other pesticides with down-the-drain transport potential. Of the 27 compounds analyzed in biosolids samples, 16 were detected in at least one sample, and 10 had a detection frequency (DF) of at least 25 %. Fipronil sulfone, fipronil sulfide, and fipronil were the most frequently detected fiproles (DF = 100 %, 94 %, and 67 %, respectively); permethrin was the most frequently detected pyrethroid (DF = 100 %), followed by bifenthrin (DF = 94 %), cyhalothrin (DF = 89 %), and etofenprox (DF = 78 %). To elucidate fipronil transformation pathways within the treatment system, data from the three sample types were compared; findings were generally consistent with transformation pathways reported previously (e.g., some fiproles were rarely detected in influent or biosolids, but frequently detected in effluent, indicating their formation during the treatment process). No correlations were found between WWTP characteristics and pesticide concentrations in biosolids. The fraction of organic carbon (fOC) of each biosolids sample was measured, and a statistically significant negative correlation was observed between fOC and some fiproles, but not fipronil; possible explanations are discussed. Additional analysis for two major agricultural pesticides (bifenthrin and permethrin) indicated that estimated mass loads of these pesticides in biosolids applied to land as a soil amendment are minimal (approximately 2 to 3 orders of magnitude lower) compared to inputs from agricultural applications. This study provides insight on the magnitude of pesticides entering the environment via land-applied biosolids; existing regulations surrounding agricultural pesticide applications are expected to also be protective of the relatively low inputs from biosolids.

City and County of San Francisco v. United States Environmental Protection Agency

Supreme Court of the United States | January 8th, 2024

For a plain language summary from Scotusblog, click here.

For a plain language summary from Scotusblog, click here.

Clean Watersheds Needs Survey 2012

U.S. Environmental Protection Agency (EPA) | December 13th, 2012

Concentrations, Loads, and Associated Trends of Nutrients Entering the Sacramento–San Joaquin Delta, California

University of California, Davis (UC Davis) | December 15th, 2021

Statistical modeling of water-quality data collected at the Sacramento River at Freeport and San Joaquin River near Vernalis, California, USA, was used to examine trends

Statistical modeling of water-quality data collected at the Sacramento River at Freeport and San Joaquin River near Vernalis, California, USA, was used to examine trends in concentrations and loads of various forms of dissolved and particulate nitrogen and phosphorus that entered the Sacramento–San Joaquin River Delta (Delta) from upstream sources between 1970 and 2019. Ammonium concentrations and loads decreased at the Sacramento River site from the mid-1970s through 1990 because of the consolidation of wastewater treatment and continuously reduced from the mid-1970s to 2019 at the San Joaquin River site. Current ammonium concentrations are mostly below 4 µM (0.056 mg N L–1) at both sites, a concentration above which reductions in phytoplankton productivity or changes in algal species composition may occur. The Sacramento River at Freeport site is located upstream of the Sacramento Regional County Sanitation District’s treatment facility’s discharge point; nutrient water quality there is representative of upstream sources. Inorganic nitrogen (nitrate plus ammonium) concentrations and loading differed at both sites. At the Sacramento River location, concentrations decrease in the summer agricultural season, reducing the molar ratios of nitrogen to phosphorus. In contrast, inorganic nitrogen concentrations increase in the San Joaquin River during the agricultural season as a result of irrigation runoff, increasing the molar ratio of nitrogen to phosphorus. This increase suggests a possible nitrogen limitation in the northern Delta and a phosphorus limitation in the southern Delta, as indicated by the molar ratios of bioavailable nitrogen to bioavailable phosphorus. Planned upgrades to the Sacramento Regional Wastewater Treatment Plant (SRWTP) will reduce inorganic nitrogen inputs to the northern Delta. Consequently, the supply of bioavailable nitrogen throughout the upper estuary should diminish. Source modeling of nitrogen and phosphorus identifies agriculture, atmospheric deposition, and wastewater effluent as sources of total nitrogen in the Central Valley. In contrast, geologic sources, agriculture, and wastewater discharge are the primary sources of phosphorus.

Constructed wetlands for winery wastewater treatment: A review on the technical, environmental and socio-economic benefits

Science of the Total Environment (Elsevier) | April 19th, 2023

In wineries, wastewater production and solid waste generation can pose serious environmental threats. Winery wastewater production has a seasonal behavior and needs a tre

In wineries, wastewater production and solid waste generation can pose serious environmental threats. Winery wastewater production has a seasonal behavior and needs a treatment system that can adapt to these fluctuations while reducing costs, and environmental impacts and promoting other winery activities. The implementation of constructed wetlands (CWs) has been demonstrated to be a competitive solution for winery wastewater and sludge treatment. In this article, worldwide experiences over the last 25 years of CWs for winery wastewater treatment are reviewed. The review shows that the application of hybrid CWs coupled with anaerobic digestion can reduce >90 % of the organic pollutants and solids from winery wastewater while avoiding clogging. These efficiencies and advantages can be also attained with French vertical systems. Not only CWs have a good technical performance, but they also reduce up to >90 % the environmental impacts associated with winery wastewater treatment. It is due to low energy requirements, no chemicals consumption and avoidance of off-site management and transportation practices. In terms of costs, CWs can reduce up to 60 times the costs associated with winery wastewater treatment and management. More efforts should be made in order to define the social benefits of this technology and the quality of the recovered resources (e.g. treated water, fertilizer) in order to promote the circular economy without compromising human and ecosystem health.

Contributions of recycled wastewater to clean water and sanitation Sustainable Development Goals

Clean Water | April 30th, 2020

Water resources are essential for every development activity, not only in terms of available quantity but also in terms of quality. Population growth and urbani

Water resources are essential for every development activity, not only in terms of available quantity but also in terms of quality. Population growth and urbanisation are increasing the number of users and uses of water, making water resources scarcer and more polluted. Changes in rainfall patterns threaten to worsen these effects in many areas. Water scarcity, due to physical lack or pollution, has become one of the most pressing issues globally, a matter of human, economic and environmental insecurity. Wastewater, whose value had not been appreciated until recently, is increasingly recognised as a potential ‘new’ source of clean water for potable and non-potable uses, resulting in social, environmental and economic benefits. This paper discusses the potential of recycled wastewater (also known as reused water) to become a significant source of safe water for drinking purposes and improved sanitation in support of the Sustainable Development Goals.

Cultivating effective utility-regulator relationships around innovation: Lessons from four case studies in the U.S. municipal wastewater sector

PLOS | August 26th, 2022

Regulation is critical for protecting public and environmental health but is often perceived as a barrier to innovation in the U.S. municipal wastewater sector. Before a

Regulation is critical for protecting public and environmental health but is often perceived as a barrier to innovation in the U.S. municipal wastewater sector. Before a wastewater utility can implement a new technology, it must navigate applicable regulatory processes and obtain necessary approvals, often including obtaining an updated wastewater discharge permit. While all regulatory processes involve interactions between regulators and regulated entities, innovative projects may require them to engage in new ways, heightening the importance of the relationships between them. We investigated four case studies to examine how regulatory relationships affect municipal wastewater utilities’ efforts to adopt new technologies. Through cross-case analysis, we identified five interconnected characteristics of regulatory relationships that appear to facilitate innovation, and whose absence could impede it: clarity, capacity building, continuity, trust, and bounded flexibility. Appropriately applied bounded flexibility—such as using regulatory discretion to tailor permits to reflect the particular risks, benefits, and information needs of the technology at issue—may be key for enabling socially and environmentally beneficial innovation. Yet all five characteristics play important and mutually reinforcing roles in supporting innovation. By cultivating these characteristics in their relationships, both utilities and regulators can take responsibility for enabling appropriate implementation of innovative technologies. However, some parties, particularly small and under-resourced utilities, may find cultivating these characteristics difficult. Therefore, sector-wide support for effective utility-regulator relationships, including coordinated regulatory and funding programs targeted to meet small utilities’ needs, may be needed to bring beneficial innovation within reach for many wastewater utilities and the communities they serve.

Estuary News, December 2014

San Francisco Estuary Partnership (SFEP) | December 15th, 2014

Estuary News, December 2018

San Francisco Estuary Partnership (SFEP) | December 15th, 2018