The Feasibility of Building Two units Combined Heat and Power (CHP) With Biogas in Urban Wastewater Treatment Plant

Limitation of fossil fuel resources together with commitment to conservation of environments have caused the views to be focused on the use of renewable energy resources. Biogas is produced by the anaerobic decomposition of organic matter in WWTPs (wastewater treatment plants) and is considered to be a sustainable energy resource due to permanency of wastewater flow. This research focuses the process of biogas fuel engine implemented in Kashan WWTPs. This system can reduce the fuel consumption rate and use renewable energies in production of heat and electrical power reliable a part of processing consumption of WWTPs. Specifications of biogas production in Kashan WWTPs is taken as sample and the necessary elements for installation and construction of biogas fuel engine are described and then two cogeneration units are designed for producing 466 kW electricity and 556 kW heat.. Costs of installations and total capital investment required for this power plant is calculated about 270,000$, which can be returned in 4 years through sales of electricity and other by-products. Also using wastewater for producing biogas reduces greenhouse emission such as methane and carbon dioxide.