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Environmental Life Cycle Assessment and Cost Analysis of Bath, NY Wastewater Treatment Plant: Potential Upgrade Implications
Citation:
Morelli, B., S. Cashman, Cissy Ma, J. Garland, D. Bless, AND J. Cashdollar. Environmental Life Cycle Assessment and Cost Analysis of Bath, NY Wastewater Treatment Plant: Potential Upgrade Implications. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-17/207, 2017.
Impact/Purpose:
Showcase the life cycle assessment and life cycle costing of a resource recovery hub from a community wastewater treatment.
Description:
Many communities across the U.S. are required to upgrade wastewater treatment plants (WWTP) to meet increasingly stringent nutrient effluent standards. However, increased capital, energy and chemical requirements of upgrades create potential trade-offs between eutrophication potential and other life cycle environmental and cost impacts. This study investigates these potential trade-offs within the context of a Southwestern New York Community considering upgrading a 1 million gallon per day conventional activated sludge system to incorporate advanced biological treatment and anaerobic digestion (AD), including co-digesting an increased quantity of the Community’s high strength organic waste. The life cycle assessment explores methods to upgrade the WWTP, while simultaneously transforming it to recover useful energy for heat and electricity, nutrients for compost, and water for irrigation. Plant operational data and engineering design documents were used to develop novel life cycle inventory for the legacy conventional activated sludge and the upgraded WWTPs. For both treatment systems, comparative results were calculated in eight environmental impact categories. Scenario analyses were employed to test the effect of co-digestion, AD operational performance, end-of-life emissions, composting methods, and landfill gas capture rate on impacts per cubic meter of wastewater treated. Low, medium, and high life cycle cost estimates were calculated for upgraded treatment system scenarios. Baseline results show that improvement in effluent quality comes at the expense of 20-30 percent increases in global warming, particulate matter formation, smog formation, fossil depletion, and acidification potential. Accepting additional organic waste and realizing peak AD performance can lead to net environmental benefits for most assessed impacts, and can result in a cost payback period less than the AD system lifespan. Such benefits are attributable to AD biogas recovery for energy generation and avoided fertilizer production from land application of compost. Global warming potential impacts were sensitive to the fraction of incoming carbon and nitrogen lost as greenhouse gases during end-of-life processing, which determines whether accepting supplemental organic waste yields a net benefit or burden. This research provides guidance for small communities around the country considering WWTP upgrades, and demonstrates the positive potential of resource recovery strategies to increase effluent quality while reducing other environmental impacts