Modeling Greenhouse Gas Emissions from Wastewater Sludge Biogas Systems in Tehran, Iran: A Review Study

Wastewater treatment protects public health. But it also hides a quiet story, one that’s often ignored. Inside its pipes and digesters, gases like methane (CH₄), nitrous oxide (N₂O) and carbon dioxide (CO₂) are released bit by bit into the air. They’re small in volume, but they matter a lot. This review looks at Tehran’s wastewater sludge biogas systems and ties local insight to global evidence. Drawing from recent works, it explores how emissions form, where they come from, and what can be done to reduce them. Results suggest that wastewater treatment contributes about ۱.۳% of global GHG emissions and maybe more than we think. Upgrading Tehran’s plants with gas-tight digesters, CHP units and thermal hydrolysis could cut those emissions by half or better while creating energy instead of losing it.

کلیدواژه ها:

Greenhouse gas ، Wastewater sludge ، Anaerobic digestion ، Life-cycle assessment ، Biogas recovery