EVALUATION OF DECENTRALIZED AND CENTRALIZED WASTEWATER TREATMENT PLANTS

In this study, it is aimed to find out which wastewater treatment plant (WWTP) is more economical by means of comparison of initial investment costs and operational costs of decentralized and centralized domestic wastewater treatment plants in and around Antalya which is located in Mediterranean Region. For this purpose, data of 14 decentralized and 5 centralized domestic wastewater treatment plants is evaluated. The design flowrates of decentralized and centralized WWTP are varying 120-900 m(3) day(-1) and 5000-22000 m(3) day(-1) respectively. As the flowrate capacity of WWTP increases, the initial investment cost and also operational cost for the treatment of per m 3 of wastewater decreases. The results show us that the mean cost of I in 3 wastewater treatment is about 0.17 $m(-3) in the decentralized wastewater treatment plants and 0.10 $m(-3) in the centralized wastewater treatment plants. This means that, collecting and transferring the wastewater to the central domestic wastewater treatment plants and making the treatment process in these plants are more economical than decentralized domestic wastewater treatment plants.