The Optimum of Detention Time on Flocculation Unit Using A Laboratory Scale Prototype

. Water used to meet the daily needs of human has different characteristics depending on the quality and amount of substances found in it. Turbidity can performance the quality of the water. The raw water used in this research comes from Kalimalang River. Coagulation and flocculation are one of the most important processes to remove the substances in raw water. Detention time is the main parameter for the flocculation process. Objectives. This research aims to find out the optimum of detention time in the flocculation prototype unit. Methods and result. Designing and assembling the flocculator lab-scale prototype using 20 cm of pipe diameter. Running the prototype and analysis the effect of detention time to the clarified water turbidity in 30 minutes of 1 Liter imhoff cone with raw water range 41-60 NTU in a long dry season. The result is the optimum clarified water turbidity is found in the 19,7 minutes detention time appropriate to the 41-60 NTU raw water turbidity range. Conclusion. The result shows, that the optimum detention time was obtained in 19,7 minutes for 41-60 NTU raw water turbidity range.