Full Scale Performance of Primary Settling Tanks

Abstract

The characteristics and the flowrate of municipal wastewater from the city of Doha, located in the Arabian Gulf have been studied to examine their effect on the performance of the primary settling tanks at the local sewage treatment plant. The wastweater is predominantly domestic and characterized by low suspended solids concentration but high total dissolved solids. The high temperature of the wastewater and long flowtime in the sewerage system turn it septic. The performance efficiency of the circular primary settling tanks in terms of total suspended solids and BOD removal was determined. Simple empirical models relating the suspended solids removal efficiency with various loading parameters like detention time, overflow rate and solids loading rate have been developed. The solids loading rate seems to be more significant than the overflow rate or the detention time in predicting settling performance. The results of the investigation are compared with published data.