Economic Evaluation of Energy Production Potential from Municipal Wastewater: Case Study Khorramabad City

Global economic development requires increasing water demand for various purposes. Wastewater treatment in these processes leads to an increase in the volume of sewage sludge. However, a significant amount of renewable energy can be recovered from sludge from wastewater treatment. Biomass is one of the energy sources that has the potential of sustainable replacement for fossil fuels, a significant part of which consists of municipal and industrial wastewater. Anaerobic digestion is used as a strategy to generate energy and biogas from municipal waste and sewage. In this study, the energy production potential of wastewater treatment plants in Khorramabad city has been investigated and evaluated using preliminary data (including BOD) on wastewater treatment performance over one year (2021). The results show that annually 2261728 cubic meters of biogas can be produced using the anaerobic digestion method. Using the combined heat and power system can generate 24879008 MW of thermal energy and 476.34 kWh of electricity. Also, the economic evaluation of the system shows that the annual investment costs and operating costs will be 103251697000 and 14620633 Rials, respectively. On the other hand, the refinery can save 44689938600 Rials annually by saving natural gas consumption, selling fertilizer produced, and selling electricity generated to the network. The rate of return on economic capital for implementing this plan is calculated for 3 years and 6 months. In addition to economic justification, implementing this plan will be able to prevent greenhouse gas emissions significantly.