ENERGY, ECONOMIC AND ENVIRONMENTAL FEASIBILITY OF ENERGY RECOVERY FROM WASTEWATER TREATMENT PLANTS IN MOUNTAINOUS AREAS: A CASE STUDY OF GHARYAN CITY – LIBYA

Wastewater treatment facilities at high places can give chances for renewable and sustainable energy generationby putting hydroelectric turbines at the input and drain channels of wastewater treatment plants, and they canalso use the sludge generated during the treatment process to make biogas, which can be used to generatepower. Purified water is subsequently used to irrigate decorative plants along highways, in gardens,and in woods. The fermentation wastes are utilized as organic fertilizer to improve agricultural soil quality.At the Gharyan sewage station, a hybrid system consisting of a hydroelectric station and an electric generatorpowered by biogas is proposed in this research. This is because the city is distinguished by its high location, whichis approximately 713 m above sea level. The results showed that the proposed system would provide an electricpower of 490 kW, which is sufficient to cover 87.5% of the electrical energy consumption of the station.The amount of treated water is approximately 13,000 m3/day, and the amount of organic fertilizer is about 17 tons/day. The investment value is anticipated to be around $1,478,000, while the cost of producing a unitof electric energy is expected to be 2.83 ¢/kWh. This system's yearly net profit is predicted to be $307,765.The capital's recovery period is anticipated to be 3.44 years. The planned hybrid system will limit the dischargeof an estimated 1,886 tons of CO2 gas each year.