Department of Civil & Environmental Engineering, Princeton University, Princeton, New Jersey08544, United States.
Now at Department of Earth Systems Science, Stanford University, Stanford, California94305, United States.
Environ Sci Technol. 2023 Mar 14;57(10):4082-4090. doi: 10.1021/acs.est.2c05373. Epub 2023 Feb 27.
An increasing percentage of US waste methane (CH) emissions come from wastewater treatment (10% in 1990 to 14% in 2019), although there are limited measurements across the sector, leading to large uncertainties in current inventories. We conducted the largest study of CH emissions from US wastewater treatment, measuring 63 plants with average daily flows ranging from 4.2 × 10 to 8.5 m s (<0.1 to 193 MGD), totaling 2% of the 62.5 billion gallons treated, nationally. We employed Bayesian inference to quantify facility-integrated emission rates with a mobile laboratory approach (1165 cross-plume transects). The median plant-averaged emission rate was 1.1 g CH s (0.1-21.6 g CH s; 10th/90th percentiles; mean 7.9 g CH s), and the median emission factor was 3.4 × 10 g CH (g influent 5 day biochemical oxygen demand; BOD) [0.6-9.9 × 10 g CH (g BOD); 10th/90th percentiles; mean 5.7 × 10 g CH (g BOD)]. Using a Monte Carlo-based scaling of measured emission factors, emissions from US centrally treated domestic wastewater are 1.9 (95% CI: 1.5-2.4) times greater than the current US EPA inventory (bias of 5.4 MMT CO-eq). With increasing urbanization and centralized treatment, efforts to identify and mitigate CH emissions are needed.
美国越来越多的废物甲烷（CH）排放来自污水处理（1990 年为 10%，2019 年为 14%），尽管该领域的测量有限，导致当前清单存在很大不确定性。我们对美国污水处理厂的 CH 排放进行了最大规模的研究，测量了 63 个平均日流量从 4.2×10 到 8.5 m s（<0.1 到 193 MGD）的工厂，占全国处理的 625 亿加仑的 2%。我们采用贝叶斯推断和移动实验室方法（1165 个交叉羽流横断面）来量化设施综合排放率。工厂平均排放率中位数为 1.1 g CH s（0.1-21.6 g CH s；10%/90%分位数；平均值为 7.9 g CH s），排放因子中位数为 3.4×10 g CH（g 五日生化需氧量；BOD）[0.6-9.9×10 g CH（g BOD）；10%/90%分位数；平均值为 5.7×10 g CH（g BOD）]。使用基于蒙特卡罗的测量排放因子缩放，美国集中处理的生活污水排放量比当前美国环保署清单高出 1.9 倍（95%置信区间：1.5-2.4）（偏差为 5.4 MMT CO-eq）。随着城市化和集中处理的增加，需要努力识别和减轻 CH 排放。
