A comparison of different pilot constructed clarifiers with the purpose of achieving the optimum condition in turbidity removal at water treatment plants in Tehran

摘要

Clarifying is one of the most crucial stages in water treatment at water treatment plants. Determining the type ofrnthe clarifier in water treatment plants and using it efficiently is necessary. In this study, a pilot is designed andrnconstructed in which the pulsator, the superpulsator and the accelerator are simulated. For each system, turbidityrnremoval efficiency for different influent turbidities and flow rates were studied and the optimum condition wasrnobtained. The results showed that the superpulsator has a superior performance compared to the pulsator, andrnthe pulsator has a superior performance compared to the accelerator and these differences are more sensible atrnhigher flow rates. Also, the best condition for achieving the highest efficiency for the pulsator and the superpulsatorrnis determined to be at flow rate 3 lit/min for an initial turbidity of 2,500 NTU with alum as the coagulant andrnthe highest efficiency for the accelerator is determined to be at flow rate 3 lit/min for an initial turbidity ofrn2,500 NTU with ferric chloride as the coagulant. Comparing the turbidity removal efficiency shows that forrn67% of the cases, ferric chloride has a better performance as the coagulant compared to alum and increasingrnthe influent turbidity leads to an increase in the removal efficiency. Furthermore, three water treatment plantsrnlocated in Tehran were studied and their characteristics were compared and suggestions were made to enhancerntheir qualities.