Modeling National Wastewater Treatment Decarbonization

Abstract Submission: Wastewater treatment plants contribute to climate change through direct emissions of methane and nitrous oxide produced during biological treatment processes, as well as indirectly through energy and chemical requirements. With many potential pathways towards decarbonizing the wastewater sector, nationwide models can guide policy and improve understanding of total impact and tradeoffs associated with different approaches. We build on our previously developed nationwide inventory of emissions from wastewater treatment to identify promising opportunities for reducing both direct and indirect emissions. Specifically, our model includes over 15,000 wastewater treatment facilities in the United States and their associated energy requirements. We also identify treatment processes present at each facility that contribute to methane and nitrous oxide emissions. We evaluate strategies for reducing direct emissions, but accurately quantifying the impact of many of these approaches is limited by the lack of high-quality measurements necessary to both understand current emissions and the impact of mitigation strategies. Thus, we also identify novel methane and nitrous oxide sensing technologies, including aircraft- and satellite-based approaches, and assess potential applicability to the wastewater treatment sector. This contributes to efforts for a nationally representative measurement campaign, the results of which in turn will better inform emissions inventories and modeling decarbonization strategies.

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