7500 tons of municipal solid waste produced in Tehran city is land-filled in Kahrizak disposal
site. The leachate of the waste has created a lake with 180000m3 in volume. A plant is under construction to
treat the leachate. A significant amount of biogas can be produced in anaerobic digestion phase in the treatment plant reactor. The designing process of a power plant in accordance with the produced biogas has been discussed in the present study. In the present investigation the air pollution from power plant has also been modeled. The leachate organic load (BOD=34400 mg/L and COD=53900 mg/L) is considerably higher when compared with other countries due to higher amount of organics available in Tehran wastes. The results indicate that an amount of 33504 m3/d biogas can be produced in Tehran’s landfill that eventually would be sufficient to run a power plant of 3.4 MW capacities. The plant which is designed by Thermoflow software is consisted of two gas turbine units with 2 MW capacities so that the total capacity is 4MW. About 10% of the generated power is for in-plant consumption and the rest can be sold. The results of the air pollution modeling using Screen 3 software reveal that CO and PM amounts are in allowed range but N2O exceeds the standard limits. The high temperature of the outlet gases emitted from gas turbines makes it possible to warm up water and regulate the anaerobic reactors temperature.