STP process was developed by adding up the individual unit processes such as primary settling, secondary treatment, secondary clarifier, sludge thickening, anaerobic digestion, sludge dewatering, and return sludge . Mechanical equipment such as pumps, thickener, aeration unit, and dewatering unit with energy consumptions were taken from the energy consumption calculations (Table ). The total energy consumption of STP was 303 kWh/1000 m 3 , after deducting the electricity generated from the biogas produced from anaerobic digestion (AD) process.