ABSTRACT
The trickling filter recirculation ratio may range from 0.5: 1 (a ratio of 0.5/1 = -5) to 5: 1 (a ratio of 5/1 = 5). However, the ratio is often found to be 1 : 1 or 2: 1.
In the treatment plant process, recirculation of mckling filter or fmal clarifier effluent may be used for various reasons such as reducing the trickling filter detention time, increasing the hydraulic loading rate, or decreasing the trickling filter influent strength, thereby improving the ability to receive shock loads. It is also used to keep the filter wet during periods of low flow.
