Environmental Planning Institute, Seoul National University, Seoul, Republic of Korea; Climate Tech Center, Seoul National University, Republic of Korea.
Department of Environmental Planning, Graduate School of Environmental Studies, Seoul National University, Seoul, 08826, Republic of Korea; Climate Tech Center, Seoul National University, Republic of Korea.
Environ Pollut. 2024 Feb 1;342:123101. doi: 10.1016/j.envpol.2023.123101. Epub 2023 Dec 8.
Methane emissions from sewer networks are an important source of anthropogenic greenhouse gases (GHGs) but are not currently reflected in the national GHG inventory. We found significant CH emissions of approximately 573 [395-831] CH t y from sewer networks in the old residential and commercial areas of Seoul (Gwanak district) using an electric vehicle-based atmospheric GHG monitoring platform. The majority of ethane-to-methane ratios (<0.005) from the observations further suggest that distinctive CH emissions from sewer networks are likely related to microbial activity rather than to simple natural gas leakage. Because over 90% of the sewer network in Seoul is a gravity drain type of combined sewer network, where both wastewater and stormwater flow through the same pipes, resulting in the generation of methane emissions from the microbial activity and the manholes and rain gutters, which are directly connected to the combined sewer networks are major sources of atmospheric methane emissions. This study suggests that appropriate treatment of sewer networks can mitigate missing methane emissions in cities that were not originally included in GHG inventory of South Korea.
下水道网络中的甲烷排放是人为温室气体（GHG）的一个重要来源，但目前并未反映在国家温室气体清单中。我们使用基于电动汽车的大气温室气体监测平台，在首尔（冠岳区）老旧居民区和商业区的下水道网络中发现了约 573[395-831] CH t y 的大量 CH 排放。观测到的大多数乙烷-甲烷比（<0.005）进一步表明，下水道网络中独特的 CH 排放可能与微生物活动有关，而不是与简单的天然气泄漏有关。由于首尔超过 90%的下水道网络是重力排水式合流下水道网络，污水和雨水都通过同一管道流动，导致来自微生物活动以及与合流下水道网络直接相连的检查井和雨水沟的甲烷排放，这些是大气甲烷排放的主要来源。本研究表明，适当处理下水道网络可以减轻韩国温室气体清单中原本未包括的城市中缺失的甲烷排放。
