This study calculated the energy and greenhouse gas life cycle and cost profiles of transitional aerobic membrane bioreactors (AeMBR) and anaerobic membrane bioreactors (AnMBR). Membrane bioreactors (MBR) represent a promising technology for decentralized wastewater treatment and can produce recycled water to displace potable water. Energy recovery is possible with methane generated from AnMBRs. Scenarios for these technologies were investigated for different scale systems serving various population densities under a number of climate conditions with multiple methane recovery options. When incorporating the displacement of drinking water, AeMBRs started to realize net energy benefits at the 1 million gallons per day (MGD) scale and mesophilic AnMBRs at the 5 MGD scale. For all scales, the psychrophilic AnMBR resulted in net energy benefits. This study provides insights into key performance characteristics needed before an informed decision can be made for a community to transition towards the adoption of MBR technologies.
The release of persistent per- and polyfluoroalkyl substances (PFAS) into
the environment is a major concern for the United States Environmental
Protection Agency (U.S. EPA). To complement its ongoing research efforts
addressing PFAS contamination, the U.S. EPA’s Office of Research and
Development (ORD) commissioned the PFAS Innovative Treatment Team (PITT) to
provide new perspectives on treatment and disposal of high priority
PFAS-containing wastes. During its six-month tenure, the team was charged with
identifying and developing promising solutions to destroy PFAS. The PITT
examined emerging technologies for PFAS waste treatment and selected four
technologies for further investigation. These technologies included
mechanochemical treatment, electrochemical oxidation, gasification and
pyrolysis, and supercritical water oxidation. This paper highlights these four
technologies and discusses their prospects and the development needed before
potentially becoming available solutions to address PFAS-contaminated waste.
When implementing anion exchange (AEX) for perand polyfluoroalkyl substances treatment, temporal drinking water quality changes from concurrent inorganic anion (IA) removal can create unintended consequences (e.g., corrosion control impacts). To understand potential effects, four drinking water-relevant IAs (bicarbonate, chloride, sulfate, and nitrate) and three gel-type, strong-base AEX resins were evaluated. Batch binary isotherm experiments provided estimates of IA selectivity with respect to chloride (K x/C ) for IA/resin combinations where bicarbonate < sulfate ≤ nitrate at studied conditions. A multi-IA batch experiment demonstrated that binary isotherm-determined K x/C values predicted competitive behavior. Subsequent column experiments with and without natural organic matter (NOM) allowed for the validation of a new ion exchange column model (IEX-CM; https://github.com/USEPA/Water_Treatment_Models). IA breakthrough was well-simulated using binary isotherm-determined K x/C values and was minimally impacted by NOM. Initial AEX effluent water quality changes with corrosion implications included increased chloride and decreased sulfate and bicarbonate concentrations, resulting in elevated chloride-to-sulfate mass ratios (CSMRs) and Larson ratios (LRs) and depressed pH until the complete breakthrough of the relevant IA(s). IEX-CM utility was further illustrated by simulating the treatment of low-IA source water and a change in the source water to understand the resulting duration of changes in IAs and water quality parameters.
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