Optimization of wastewater treatment plant layout, siting, and environmental protection strategies based on odorous gas dispersion.

The emission of malodorous gases from wastewater treatment plants (WWTPs) poses significant environmental challenges, leading to odor nuisances and health risks for nearby communities. This study investigated odor pollution from a county-level WWTP in northern China, focusing on volatile sulfur compounds (VSCs) as key pollutants. On-site monitoring of VSCs emitted from the WWTP was conducted to simulate the dispersion behavior of VSCs in the atmosphere using the AERMOD dispersion model, and to quantitatively assess the olfactory impacts of VSCs on neighboring residents and evaluate the health risks associated with H2S. Findings indicate that the primary sedimentation tank (PST) and biological tanks were the main VSC sources, contributing 94.29 % of total emissions. Dimethyl disulfide (DMDS) and hydrogen sulfide (H2S) were the most prevalent, accounting for 43.29 % and 38.09 % of emissions, respectively. Source tracing identified the PST and biological tanks as primary contributors to odor and health risks in adjacent residential areas. The study proposed recommendations to optimize the WWTP layout, define olfactory and health protection zones, and enhance the site selection process to mitigate the adverse effects on the local environment and improve residents' quality of life.