Application of TAPM–AERMOD model system to assess pollution dispersion and propose odor control solutions at Dap Da landfill, Dong Thap province

Abstract

Domestic solid waste landfills are major sources of unpleasant odors that negatively affect the quality of life of nearby communities. In recent years, odor pollution has become a significant environmental concern in Viet Nam in general and in Dong Thap province in particular. This study aimed to assess the current status of odor pollution and to apply the integrated TAPM–AERMOD modeling system to simulate odor dispersion at the Dap Da landfill, thereby proposing appropriate solutions to mitigate odor impacts and protect the surrounding air environment. Emission loads of ammonia (NH₃), hydrogen sulfide (H₂S), and methyl mercaptan (CH₃SH) were estimated based on the emission factor method. Simulation results indicated that the highest 1-hour average concentration of NH₃ reached 1,000 µg/m³, with concentrations ranging from 200 to 500 µg/m³ and a maximum dispersion distance of approximately 2 km, primarily toward the northwest. The highest 1-hour average concentration of H₂S was 165 µg/m³, with values between 42 and 80 µg/m³ and a maximum dispersion distance of 2.1 km, mainly toward the northeast. For CH₃SH, the highest 1-hour average concentration was 71.8 µg/m³, with dispersion distances up to 623 m, predominantly in the northeast direction. Two future expansion scenarios of the landfill up to 2050 were also evaluated. The results showed that pollutant concentrations could increase by 1.5–2.0 times, while dispersion distances could increase by 1.3–1.5 times in scenario 1 and 3.2–4.0 times in scenario 2 compared to current conditions. Based on these findings, effective odor control and pollution reduction solutions were proposed for the Dap Da landfill.