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In April 2015, the Governor of California mandated a 25% statewide reduction in water consumption (relative to 2013 levels) by urban water suppliers. The more than 400 public water agencies affected by the regulation were also required to report monthly progress towards the conservation goal to the State Water Resources Control Board. This paper uses the reported data to assess how the water utilities have responded to this mandate and to estimate the electricity savings and greenhouse gas (GHG) emissions reductions associated with reduced operation of urban water infrastructure systems. The results show that California succeeded in saving 524 000 million gallons (MG) of water (a 24.5% decrease relative to the 2013 baseline) over the mandate period, which translates into 1830 GWh total electricity savings, and a GHG emissions reduction of 521 000 metric tonnes of carbon dioxide equivalents (MT CO2e). For comparison, the total electricity savings linked to water conservation are approximately 11% greater than the savings achieved by the investor-owned electricity utilities' efficiency programs for roughly the same time period, and the GHG savings represent the equivalent of taking about 111 000 cars off the road for a year. These indirect, large-scale electricity and GHG savings were achieved at costs that were competitive with existing programs that target electricity and GHG savings directly and independently. Finally, given the breadth of the results produced, we built a companion website, called 'H2Open' (https://cwee.shinyapps.io/greengov/), to this research effort that allows users to view and explore the data and results across scales, from individual water utilities to the statewide summary.

Using data from the water service area of the East Bay Municipal Utility District in Northern California, we develop and discuss a method for assessing, at a high resolution, the energy intensity of water treated and delivered to customers of a major metropolitan water district. This method extends previous efforts by integrating hourly data from supervisory control and data acquisition systems with calculations based on the actual structure of the engineered infrastructure to produce a detailed understanding of energy use in space and time within the territory of a large-scale urban water provider. We found significant variations in the energy intensity of delivered potable water resulting from seasonal and topographic effects. This method enhances our understanding of the energy inputs for potable water systems and can be applied to the entire delivery and postuse water life cycle. A nuanced understanding of water's energy intensity in an urban setting enables more intelligent, targeted efforts to jointly conserve water and energy resources that take seasonal, distance, and elevation effects into account.

By community intervention in 14 non-disinfecting municipal water systems, we quantified sporadic acute gastrointestinal illness (AGI) attributable to groundwater. Ultraviolet (UV) disinfection was installed on all supply wells of intervention communities. In control communities, residents continued to drink non-disinfected groundwater. Intervention and control communities switched treatments by moving UV disinfection units at the study midpoint (crossover design). Study participants (n = 1,659) completed weekly health diaries during four 12-week surveillance periods. Water supply wells were analyzed monthly for enteric pathogenic viruses. Using the crossover design, groundwater-borne AGI was not observed. However, virus types and quantity in supply wells changed through the study, suggesting that exposure was not constant. Alternatively, we compared AGI incidence between intervention and control communities within the same surveillance period. During Period 1, norovirus contaminated wells and AGI attributable risk from well water was 19% (95% CI, -4%, 36%) for children <5 years and 15% (95% CI, -9%, 33%) for adults. During Period 3, echovirus 11 contaminated wells and UV disinfection slightly reduced AGI in adults. Estimates of AGI attributable risks from drinking non-disinfected groundwater were highly variable, but appeared greatest during times when supply wells were contaminated with specific AGI-etiologic viruses.

Wastewater-based epidemiology offers a time- and cost-effective way to monitor SARS-CoV-2 spread in communities and therefore represents a complement to clinical testing. WBE applicability has been demonstrated in a number of cases over short-term periods as a method for tracking the prevalence of SARS-CoV-2 and an early-warning tool for predicting outbreaks in the population. This study reports SARS-CoV-2 viral loads from wastewater treatment plants (WWTPs) and hospitals over a 6-month period (June to December 2020). Results show that the overall range of viral load in positive tested samples was between 1.2 × 10 3 and 3.5 × 10 6 gene copies/l, unveiling that secondary-treated wastewaters mirrored the viral load of influents. The interpretation suggests that the viral titers found in three out of four WWTPs were associated to clinical COVID-19 surveillance indicators preceding 2-7 days the rise of reported clinical cases. The median wastewater detection rate of SARS-CoV-2 was one out of 14,300 reported new cases. Preliminary model estimates of prevalence ranged from 0.02 to 4.6% for the studied period. This comprehensive statistical and epidemiological analysis demonstrates that the applied wastewater-based approach to COVID-19 surveillance is in general consistent and feasible, although there is room for improvements., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

A literature review was carried out to analyze the current status of microplastic research in Latin America and the Caribbean (LAC). Specifically, this work focused on publications pertaining to (1) occurrence and distribution of microplastics in the environment, including water, sediments, and soil and (2) the environmental impact of MPs, particularly their presence and effects on aquatic and terrestrial organisms. The review included peer-reviewed articles from Scopus, Science Direct, Web of Science, Google Scholar and two iberoamerican open access databases (Redalyc and SciELO). It was found that LAC has only contributed to 5% of the global scientific output on microplastics, and overall the highest contributor within the region was Brazil (52%), followed by Chile (16%) and Mexico (13%). An additional section analyzing the barriers to conducting microplastic research in LAC and their exacerbation by the current COVID-19 pandemic was included to provide additional context behind the relatively low scientific production and improve recommendations encouraging research in this region., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

We previously observed that exposure to a complex mixture of high molecular weight polycyclic aromatic hydrocarbons (PAHs) increased sensitivity of rainbow trout (Oncorhynchus mykiss) to subsequent challenge with Aeromonas salmonicida, the causative agent of furunculosis. In this study, we evaluate potential mechanisms associated with disease susceptibility from combined environmental factors of dietary PAH exposure and pathogen challenge. Rainbow trout were fed a mixture of ten high molecular weight PAHs at an environmentally relevant concentration (7.82μg PAH mixture/g fish/day) or control diet for 50 days. After 50 days of PAH exposure, fish were challenged with either Aeromonas salmonicida at a lethal concentration 30 (LC 30 ) or growth media without the pathogen (mock challenge). Head kidneys were collected 2, 4, 10 and 20 days after challenge and gene expression (q<0.05) was evaluated among treatments. In animals fed the PAH contaminated diet, we observed down-regulation of expression for innate immune system genes in pathways (p<0.05) for the terminal steps of the complement cascade (complement component C6) and other bacteriolytic processes (lysozyme type II) potentially underlying increased disease susceptibility after pathogen challenge. Increased expression of genes associated with hemorrhage/tissue remodeling/inflammation pathways (p<0.05) was likely related to more severe head kidney damage due to infection in PAH-fed compared to control-fed fish. This study is the first to evaluate transcriptional signatures associated with the impact of chronic exposure to an environmentally relevant mixture of PAHs in disease susceptibility and immunity., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: Groundwater supplies for drinking water are frequently contaminated with low levels of human enteric virus genomes, yet evidence for waterborne disease transmission is lacking., Objectives: We related quantitative polymerase chain reaction (qPCR)-measured enteric viruses in the tap water of 14 Wisconsin communities supplied by nondisinfected groundwater to acute gastrointestinal illness (AGI) incidence., Methods: AGI incidence was estimated from health diaries completed weekly by households within each study community during four 12-week periods. Water samples were collected monthly from five to eight households per community. Viruses were measured by qPCR, and infectivity assessed by cell culture. AGI incidence was related to virus measures using Poisson regression with random effects., Results: Communities and time periods with the highest virus measures had correspondingly high AGI incidence. This association was particularly strong for norovirus genogroup I (NoV-GI) and between adult AGI and enteroviruses when echovirus serotypes predominated. At mean concentrations of 1 and 0.8 genomic copies/L of NoV-GI and enteroviruses, respectively, the AGI incidence rate ratios (i.e., relative risk) increased by 30%. Adenoviruses were common, but tap-water concentrations were low and not positively associated with AGI. The estimated fraction of AGI attributable to tap-water-borne viruses was between 6% and 22%, depending on the virus exposure-AGI incidence model selected, and could have been as high as 63% among children < 5 years of age during the period when NoV-GI was abundant in drinking water., Conclusions: The majority of groundwater-source public water systems in the United States produce water without disinfection, and our findings suggest that populations served by such systems may be exposed to waterborne viruses and consequent health risks.

The health effects of the flame retardant polybrominated diphenyl ethers (PBDEs) in fish are not well understood. To determine the potential effects of this ubiquitous contaminant class on fish health, juvenile subyearling Chinook salmon (Oncorhynchus tshawytscha) were fed a diet that reflected the PBDE congeners found in the stomach contents of subyearling Chinook salmon collected from the highly urbanized and industrialized lower Willamette River in the Columbia River Basin of North America. The diet, consisting of five PBDE congeners (BDE-47, BDE-99, BDE-100, BDE-153 and BDE-154), was fed to the salmon at 2% of their body weight in food per day for 40 days. Two concentrations of the diet (1x and 10x PBDE) were fed to the salmon. The 1x PBDE diet reflected the concentration of PBDEs (190 ng PBDEs/g food) found in the stomach contents of juvenile subyearling Chinook salmon; the 10x diet was prepared at 10 times that concentration. The fish were then exposed to the marine bacterial pathogen Listonella anguillarum to assess susceptibility to infectious disease. Juvenile Chinook salmon fed the 1x PBDE diet were more susceptible to L. anguillarum than salmon fed the control diet. This suggests that juvenile salmonids in the lower Willamette River exposed to PBDEs may be at greater risk for disease than nonexposed juvenile salmonids. In contrast, salmon that consumed the 10x PBDE diet were not more susceptible to the pathogen than salmon fed the control diet. The mechanisms for the dichotomous results observed in disease susceptibility between salmon fed the 1x and 10x PBDE diets are currently not known but have also been observed in other species exposed to PBDEs with respect to immune function., (Published by Elsevier B.V.)

The transfer of genetic material among bacteria in the environment can occur both in the planktonic and attached state. Given the propensity of organisms to exist in sessile microbial communities in oligotrophic subsurface conditions, and that such conditions typify the subsurface, this study focuses on exploratory modeling of horizontal gene transfer among surface-associated Escherichiacoli in the subsurface. The mathematics so far used to describe the kinetics of conjugation in biofilms are developed largely from experimental observations of planktonic gene transfer, and are absent of lags or plasmid stability that appear experimentally. We develop a model and experimental system to quantify bacterial filtration and gene transfer in the attached state, on granular porous media. We include attachment kinetics described in Nelson et al. (2007) using the filtration theory approach of Nelson and Ginn (2001, 2005) with motility of E. coli described according to Biondi et al. (1998)., (Copyright 2009 Elsevier B.V. All rights reserved.)

Available filtration methods to concentrate waterborne viruses are either too costly for studies requiring large numbers of samples, limited to small sample volumes, or not very portable for routine field applications. Sodocalcic glass wool filtration is a cost-effective and easy-to-use method to retain viruses, but its efficiency and reliability are not adequately understood. This study evaluated glass wool filter performance to concentrate the four viruses on the U.S. Environmental Protection Agency contaminant candidate list, i.e., coxsackievirus, echovirus, norovirus, and adenovirus, as well as poliovirus. Total virus numbers recovered were measured by quantitative reverse transcription-PCR (qRT-PCR); infectious polioviruses were quantified by integrated cell culture (ICC)-qRT-PCR. Recovery efficiencies averaged 70% for poliovirus, 14% for coxsackievirus B5, 19% for echovirus 18, 21% for adenovirus 41, and 29% for norovirus. Virus strain and water matrix affected recovery, with significant interaction between the two variables. Optimal recovery was obtained at pH 6.5. No evidence was found that water volume, filtration rate, and number of viruses seeded influenced recovery. The method was successful in detecting indigenous viruses in municipal wells in Wisconsin. Long-term continuous filtration retained viruses sufficiently for their detection for up to 16 days after seeding for qRT-PCR and up to 30 days for ICC-qRT-PCR. Glass wool filtration is suitable for large-volume samples (1,000 liters) collected at high filtration rates (4 liters min(-1)), and its low cost makes it advantageous for studies requiring large numbers of samples.

Polyhydroxyalkanoate (PHA) production was achieved using tomato cannery waste coupled with a mixed microbial culture during wastewater treatment. The two-stage PHA production process comprised a sequencing batch reactor (SBR), operating under a periodic feast-famine regime, to accomplish simultaneously wastewater treatment and selection of PHA-accumulating microbes, followed by a batch reactor for the production of PHA-rich biomass. The SBRs were efficient at removing soluble carbon (84%), ammonia (100%), and phosphorus (76%). Meanwhile, PHA-accumulating microbes were enriched under the SBR operating conditions, and PHA content on a cell-weight basis was within the range 7 to 11% in nonfiltered wastewater and 2 to 8% in filtered wastewater. Subsequently, batch studies were implemented with varying loading rates, ranging from 0.4 to 3.2 food-to-microorganism ratios. A maximum 20% PHA content on a cell-weight basis was obtained. Based on the experimental results, a PHA biosynthesis-degradation kinetic model was developed to (1) aid in the design of a pilot- or full-scale PHA production process coupled with wastewater treatment and (2) determine optimal conditions for harvest of PHA-rich biomass.

Biologically derived polyesters known as polyhydroxyalkanoates (PHAs) represent a potentially "sustainable" replacement to fossil-fuel-based thermoplastics. However, current commercial practices that produce PHA with pure microbial cultures grown on renewable, but refined, feedstocks (i.e., glucose) under sterile conditions do not represent a sustainable commodity. Here, we report on PHA production with a mixed microbial consortium indigenous to an activated sludge process on carbon present in municipal wastewaters. Reactors operated under anaerobic/aerobic and aerobic-only mode and fed primary solids fermenter liquor maintained a mixed microbial consortium capable of synthesizing PHA at 10 to 25% (w/w), while reducing soluble COD by approximately 62 to 71%. More critically, an aerobic batch reactor seeded from the anaerobic/aerobic reactor and fed fermenter liquor achieved approximately 53% PHA (w/w). Results presented suggest that environmentally benign production of biodegradable polymers is feasible. We further used PHA-rich biomass to produce a natural fiber-reinforced thermoplastic composite that can be used to offset advanced wastewater treatment costs.

Direct current applied to a tin oxide anode submersed in water has the potential to generate hydroxyl radicals, a strong chemical oxidant. Tin oxide anode systems, which may represent a viable alternative disinfectant, were investigated for the disinfection of secondary effluents. Coliform bacteria in the effluent were effectively inactivated in a bench-scale tin oxide disinfection system. The number of anodes in the tin oxide disinfection system influenced the steady-state concentration of hydroxyl radicals and, consequently, the contact time necessary to achieve a specified dose. The life expectancy of the anodes was greater than 30 days and no appreciable loss of tin was observed over a 5-day period. A preliminary estimate of the capital and operating costs of a pilot- or full-scale tin oxide disinfection system designed to meet a discharge requirement of 23 most probable number/100 mL at a 3 785-m3/d (1-mgd) facility was comparable to UV and chlorination/dechlorination facilities. Based on this preliminary assessment, tin oxide disinfection systems are a promising alternative disinfectant for secondary effluents.

We describe the protocol for an inexpensive and nondestructive optical reflectance assay for the measurement of biofilm formation. Reflectance data are obtained using an Ocean Optics (Dunedin, Florida) USB 2000 spectrometer with a polychromatic light source. A fiber optic cable is used both for illumination and collection, and Ocean Optics OOIBase32 Platinum software is used for preliminary processing of the data. Differences in reflectance data collected at times ranging from 2 to 24 h distinguish between cell attachment and volume growth for two strains of Enterococci. Confocal scanning laser microscopy imaging is used to confirm these results. Phase contrast microscopy images are also obtained in conjunction with reflectance measurements for several different biofilm specimens. The experiments consider biofilm formation on glass and polystyrene substrata, but the method can be used for many other abiotic substrata of interest, both opaque and nonopaque.

We developed a DNA microarray suitable for simultaneous detection and discrimination between multiple bacterial species based on 16S ribosomal DNA (rDNA) polymorphisms using glass slides. Microarray probes (22- to 31-mer oligonucleotides) were spotted onto Teflon-masked, epoxy-silane-derivatized glass slides using a robotic arrayer. PCR products (ca. 199 bp) were generated using biotinylated, universal primer sequences, and these products were hybridized overnight (55 degrees C) to the microarray. Targets that annealed to microarray probes were detected using a combination of Tyramide Signal Amplification and Alexa Fluor 546. This methodology permitted 100% specificity for detection of 18 microbes, 15 of which were fish pathogens. With universal 16S rDNA PCR (limited to 28 cycles), detection sensitivity for purified control DNA was equivalent to <150 genomes (675 fg), and this sensitivity was not adversely impacted either by the presence of competing bacterial DNA (1.1 x 10(6) genomes; 5 ng) or by the addition of up to 500 ng of fish DNA. Consequently, coupling 16S rDNA PCR with a microarray detector appears suitable for diagnostic detection and surveillance for commercially important fish pathogens.

Polymerase chain reaction (PCR) was used to detect Cryptosporidium parvum oocysts in secondary effluent samples collected from activated-sludge facilities. Serial dilutions of the purified nucleic acid extracts from the samples were made and PCR was conducted to estimate the C. parvum oocyst concentration via a Poisson distribution-based most probable number (MPN). The degree of oocysts associated with wastewater particles was also evaluated. The sensitivity of the MPN-PCR assay was 20 oocysts/PCR unit. The detection limit of the concentration, extraction, and purification protocols in phosphate buffer saline spiked with a known concentration of oocysts ranged from 1.1 to 4.6 oocysts/L; the detection limit for the wastewater samples ranged from 11 to 4200 oocysts/L depending on the extent of inhibition in each sample. The recovery efficiency of the oocysts ranged from 48 to 59% in most samples. Oocysts were found in two out of seven samples with concentrations of 203 and 308 oocysts/L, as estimated by the MPN-PCR method. The oocysts were found only in the filtrate of the grab samples; particle-associated oocysts were not detected. Association of spiked C. parvum oocysts with particles in secondary effluent drawn from wastewater plants with varying operating conditions indicated a weak correlation between the degree of association and the mean cell residence time of the system.