Investigating Municipal Solid Waste Disposal Sites as Hotspots for Greenhouse Gas Emissions (Case Study: City of Karaj), Iran

Khazaei, Sayyed Hossein; Moeinaddini, Mazaher; Rafiee, Reza; Khorasani, Nematollah; Mollaei, Azad

doi:10.22113/jmst.2026.583368.2692

Investigating Municipal Solid Waste Disposal Sites as Hotspots for Greenhouse Gas Emissions (Case Study: City of Karaj), Iran

Articles in Press

Document Type : Original Manuscript

Authors

Sayyed Hossein Khazaei ¹^{, 2}

Mazaher Moeinaddini ²

Reza Rafiee ²

Nematollah Khorasani ²

Azad Mollaei ²

¹ Department of Environmental Sciences, Faculty of Marine Natural Resources, Khorramshahr University of Marine Science and Technology, Khorramshahr, Iran

² Department of Environmental Sciences, Faculty of Natural Resources, University of Tehran, Karaj, Iran.

10.22113/jmst.2026.583368.2692

Abstract

Landfills are the third-largest source of anthropogenic methane emissions, contributing significantly to greenhouse gas emissions. However, in Iran, due to the predominance of non-engineered landfills and the absence of gas extraction systems, the actual rates of methane emission and oxidation remain poorly understood. This study aimed to measure field-scale methane emission and oxidation at the Halgheh Dareh landfill in Karaj, identified as a critical hotspot for greenhouse gas emissions. Sampling was conducted using the static chamber method during summer and winter across three cells of different waste ages (1–2, 4–5, and 15 years), with a total of 141 sampling points. Results showed that the mean methane emission rate was 284 g/m²/day (equivalent to 104 kg/m²/year), and the mean oxidation rate was 25%, significantly higher than the IPCC default value of 10%. The highest emission rate was recorded in the young cell (1–2 years old): 529.63 g/m²/day in summer and 2462.61 g/m²/day in winter. In the 15-year-old cell, emissions dropped to below 120 g/m²/day, indicating that the landfill had entered the stabilization phase (Stage 5 of biogas production). The result indicated that the Karaj landfill is a significant source of greenhouse gas emissions.

Keywords

Methane emission

Landfill

Methane Oxidation

Greenhouse gases

Karaj

Subjects