Evaluation of İznik and Yenisehir municipality wastewater treatment plants in terms of performance and energy efficiency

In this study, a comparison was made on the treatment efficiency of gray water, based on the İznik WWTP, which has a submerged membrane bioreactor (MBR) system, and the Yenişehir WWTP, which has advanced biological treatment. For this purpose, pollution parameters such as suspended solids (SS), chemical oxygen demand (COD), biological oxygen demand (BOD), total nitrogen (TN), total phosphorus (TP), as well as consumed energy, water consumption and flow data were used in the study. Among the facilities discussed in this study, Iznik WWTP purifies with a membrane unit immersed in the aeration tank and a microfiltration module with an average pore size of 0.4 μm, while Yenişehir WWTP has an activated sludge system with long aeration and purifies according to the A^2 O process. The average values for the removal efficiencies in the AKM, COD, BOD, TN and TP parameters are 97%, 93%, 97%, 86% and 81% for Iznik WWTP, respectively, while they are 95%, 93%, 98.9%, 95%, 93%, 98.9% and 81% for Yenişehir WWTP, respectively. It was determined as 90 and 90%. The results obtained during these studies have been met with the relevant standards in the regulation, and the values in the outlet water have been determined to meet the required standards. For all observed times, the required energy per COD for İznik and Yenişehir WWTP was determined as 4.04±0.61 and 1.81±0.5 kW.h/COD, respectively, and the energy consumption per cubic meter of treated wastewater was determined as 1.35±. 0.1 and 0.67±0.13 Kw.hour/m^3 for Yenişehir. While the highest water consumption in treatment plants occurs in sludge dewatering units, Iznik WWTP uses its own purified water for sludge dewatering with a decanter, while Yenişehir WWTP uses both drinking water and a serious water consumption of 5000 m^3/month with a belt filter press. In line with the parameters examined in this study, it is thought that focusing on the removal efficiencies of polluting nutrients in two separate treatment plants operated with completely different processes and comparing their energy efficiencies will provide guidance in choosing treatment systems.