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1. Reduction in urban water use leads to less wastewater and fewer emissions:analysis of three representative U.S. cities

   https://doi.org/10.1088/1748-9326/ab8dd8  

   Gursel, Aysegul Petek ; Chaudron, Camille ; Kavvada, Ioanna ; Horvath, Arpad ( July 2020 , Environmental Research Letters)

   Electricity consumption and greenhouse gas (GHG) emissions associated with wastewater flows from residential and commercial water use in three major cities of the United States are analyzed and compared for the period 2010–2018. Contributions of unit wastewater treatment processes and electricity sources to the overall emissions are considered. Tucson (Arizona), Denver (Colorado), and Washington, DC were chosen for their distinct locations, climatic conditions, raw water sources, wastewater treatment technologies, and electric power mixes. Denver experienced a 20% reduction in treated wastewater volumes per person despite a 16% increase in population. In Washington, DC, the reduction was 19%, corresponding to a 16% increase in population, and in Tucson 14% despite a population growth of 3%. The electricity intensity per volume of treated wastewater was higher in Tucson (1 kWh m⁻³) than in Washington, DC (0.7 kWh m⁻³) or Denver (0.5 kWh m⁻³). Tucson’s GHG emissions per person were about six times higher compared to Denver and four times higher compared to Washington, DC. Wastewater treatment facilities in Denver and Washington, DC generated a quarter to third of their electricity needs from onsite biogas and lowered their GHG emissions by offsetting purchases from the grid, including coal-generated electricity. The higher GHG emission intensity in Tucson is a reflection of coal majority in the electricity mix in the period, gradually replaced with natural gas, solar, and biogas. In 2018, the GHG reduction was 20% when the share of solar electricity increased to 14% from zero in 2016. In the analysis period, reduced wastewater volumes relative to the 2010 baseline saved Denver 44 000 MWh, Washington, DC 11 000 MWh and Tucson 7000 MWh of electricity. As a result, Washington, DC managed to forgo 21 000 metric tons of CO_2-eqand Denver 34 000 metric tons, while Tucson’s cumulative emissions increased by 22 000 metric tons of CO_2-eq. This study highlights the variability observed in water systems and the opportunities that exist with water savings to allow for wastewater generation reduction, recovering energy from onsite biogas, and using energy-efficient wastewater treatment technologies.

    

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2. UTEP–EPW university–utility partnership: Concentrate enhanced–recovery reverse osmosis process for high water recovery from silica‐saturated desalination concentrates

   https://doi.org/10.1002/wer.1176  

   Tarquin, Anthony ; Walker, William Shane ; Delgado, Guillermo ; Bustamante, Angel ( July 2019 , Water Environment Research)

   Since the 1970s, The University of Texas at El Paso and El Paso Water have had a synergistic university–utility partnership, and in 2002, we began a sequence of investigations of enhanced recovery of water from silica‐saturated reverse osmosis concentrate: (a) two‐pass nanofiltration (NF) and reverse osmosis (RO) treatment, (b) lime softening for silica removal, (c) vibratory shear enhanced processing (VSEP), (d) continuous‐flow seawater RO treatment of brackish RO concentrate, and finally (e) high‐recovery concentrate enhanced‐recovery reverse osmosis (CERRO) process. Studies funded by El Paso Water, Texas Water Development Board, U.S. Bureau of Reclamation, and WateReuse Research Foundation were conducted at the Kay Bailey Hutchison (KBH) Plant in El Paso and the Brackish Groundwater National Desalination Research Facility in Alamogordo, NM, and showed that as much as 88% of the water could be recovered from silica‐saturated KBH concentrate using the CERRO process. Full‐scale implementation of the CERRO process at well sites in El Paso has resulted in 70%–75% recovery of RO concentrate with a specific energy consumption of 1.23 kWh/m³(4.6 kWh/kgal) and total estimated cost of approximately $0.59/m³($2.25/kgal). Cost‐effective high‐recovery desalination technologies such as CERRO are essential for drought‐proof water supply in arid cities such as El Paso.

   This two‐decade UTEP‐EPW research partnership was sustained by a long‐term commitment to research and consistent financial support from EPW.

   Universities can collaborate to leverage utility funding toward larger external grant funding to advance research and development in a win–win partnership.

   The high‐recovery CERRO process was developed through multiple phases of concentrate management research, which would not have been possible without long‐term research commitment and risk tolerance from EPW.

   CERRO systems are being implemented at full scale in El Paso to recover water from silica‐saturated RO concentrate at an estimated specific energy consumption of 1.23 kWh/m³(4.6 kWh/kgal) and total amortized cost of $0.59/m³($2.25/kgal).

    

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3. Drinking water improvements and rates of urinary and gastrointestinal infections in Galápagos, Ecuador: Assessing household and community factors

   https://doi.org/10.1002/ajhb.23358  

   Houck, Kelly M. ; Terán, Enrique ; Ochoa, Juan ; Zapata, Gyssell N. ; Gomez, Ana M. ; Parra, Rafael ; Dvorquez, Denise ; Stewart, Jill R. ; Bentley, Margaret E. ; Thompson, Amanda L. ( November 2019 , American Journal of Human Biology)

   The Galápagos provides an important setting to investigate the health impacts of a new drinking water treatment plant (DWTP) in a limited resource environment. We examine how household perceptions and practices affect the relationship between water quality and infections before and after DWTP.

   Ethnographic data and self‐reported infections were collected from 121 mothers and 168 children ages 2 to 10 from Isla San Cristóbal. Household tap water samples were tested for levels of fecal contamination. Community level infection rates were estimated using discharge records from the Ministry of Public Health. The effects of the new DWTP and fecal contamination levels on infections were tested using logistic and Poisson models.

   Perceptions of water quality and household practices influenced exposures to contaminated tap water. We found minimal change in drinking water sources with 85% of mothers sampled before the DWTP and 83% sampled after using bottled water, while >85% from the pooled sample used tap water for cooking and hygiene practices. The DWTP opening was associated with lower odds of fecal contamination in tap water, reported urinary infections, and community level rates of urinary and gastrointestinal infections. The household practice of recently washing the cistern contributed to higher contamination levels after the DWTP opened.

   To ensure access to clean water, public health works need to consider how household perceptions and practices influence tap water use and quality, in addition to infrastructure improvements. Exposures to contaminated tap water contribute to the burden of infectious disease in environments with inadequate water infrastructure.

    

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4. Mass transport-enhanced electrodeposition of Ni–S–P–O films on nickel foam for electrochemical water splitting

   https://doi.org/10.1039/D0TA12097A  

   Marquez-Montes, Raul A. ; Kawashima, Kenta ; Son, Yoon Jun ; Weeks, Jason A. ; Sun, H. Hohyun ; Celio, Hugo ; Ramos-Sánchez, Víctor H. ; Mullins, C. Buddie ( March 2021 , Journal of Materials Chemistry A)

   null (Ed.)

   Electrochemical water splitting is one of the most promising approaches for sustainable energy conversion and storage toward a future hydrogen society. This demands durable and affordable electrocatalysts for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). In this study, we report the preparation of uniform Ni–P–O, Ni–S–O, and Ni–S–P–O electrocatalytic films on nickel foam (NF) substrates via flow cell-assisted electrodeposition. Remarkably, electrodeposition onto 12 cm 2 substrates was optimized by strategically varying critical parameters. The high quality and reproducibility of the materials is attributed to the use of a 3D-printed flow cell with a tailored design. Then, the as-fabricated electrodes were tested for overall water splitting in the same flow cell under alkaline conditions. The best-performing sample, NiSP/NF, required relatively low overpotentials of 93 mV for the HER and 259 mV for the OER to produce a current density of 10 mA cm −2 . Importantly, the electrodeposited films underwent oxidation into amorphous nickel (oxy)hydroxides and oxidized S and P species, improving both HER and OER performance. The superior electrocatalytic performance of the Ni–S–P–O films originates from the unique reconstruction process during the HER/OER. Furthermore, the overall water splitting test using the NiSP/NF couple required a low cell voltage of only 1.85 V to deliver a current density of 100 mA cm −2 . Overall, we demonstrate that high-quality electrocatalysts can be obtained using a simple and reproducible electrodeposition method in a robust 3D-printed flow cell. 

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5. Using Building Energy and Smart Thermostat Data to Evaluate Indoor Ultrafine Particle Source and Loss Processes in a Net-Zero Energy House

   https://doi.org/10.1021/acsestengg.1c00002  

   Jiang, Jinglin ; Jung, Nusrat ; Boor, Brandon E. ( January 2021 , ACS ES&T Engineering)

   null (Ed.)

   The integration of Internet of Things (IoT)-enabled sensors and building energy management systems (BEMS) into smart buildings offers a platform for real-time monitoring of myriad factors that shape indoor air quality. This study explores the application of building energy and smart thermostat data to evaluate indoor ultrafine particle dynamics (UFP, diameter ≤ 100 nm). A new framework is developed whereby a cloud-based BEMS and smart thermostats are integrated with real time UFP sensing and a material balance model to characterize UFP source and loss processes. The data-driven framework was evaluated through a field campaign conducted in an occupied net-zero energy building—the Purdue Retrofit Net-zero: Energy, Water, and Waste (ReNEWW) House. Indoor UFP source events were identified through time-resolved electrical kitchen appliance energy use profiles derived from BEMS data. This enabled determination of kitchen appliance-resolved UFP source rates and time-averaged concentrations and size distributions. BEMS and smart thermostat data were used to identify the operational mode and runtime profiles of the air handling unit and energy recovery ventilator, from which UFP source and loss rates were estimated for each mode. The framework demonstrates that equipment-level energy use data can be used to understand how occupant activities and building systems affect indoor air quality. 

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