Reuse of treated domestic wastewater: Kaş case study

Coastal waters face with pollution problems due to urbanization, increasing population and various tourism activities. Domestic wastewaters of settlements located on the seaside are mostly discharged into the sea environment after the treatment. In this study, the necessity of reuse of wastewaters instead of dicharging them into the coastal waters after the treament has been investigated. Kaş District of Antalya located in the Western Mediterranean Basin of Turkey that is valuable location regarding coastal tourism has been chosen as the case study area. The wastewater treatment plant in the district is located in Çukurbağ Peninsula, which is very valuable for tourism activities. Considering the tourism potential of the district, possible future capacity increases in the wastewater treatment plant will not be possible due to the narrow topography of the land. The treated Kaş domestic wastewaters are discharged to the coastal waters of Kaş Bay by a sea outfall system. In order to understand the transport processes in the coastal waters of Kaş Bay, wind climate, wave climate and current climate have been analyzed using the HYDROTAM-3D numerical model and the far-field dilutions of pollutants discharged into the sea have been modeled. Modeling studies have shown that the pollution cloud can lead to water quality problems within the Bay in near future. The existence of agricultural lands in the region increases the importance of the reuse. Based on modeling studies, it is suggested that the waste water treatment plant be removed from Çukurbağ Peninsula and redesigned using advanced biological treatment methods. It should be ensured that wastewater treated with advanced treatment is reused for agricultural irrigation or urban irrigation. For all similar coastal cities in Turkey, reuse of treated wastewaters discharged into the sea should be included in the sustainable water management plans.