Experimental Study of Flow Characteristics in Filtering Element of Powdered Activated Carbon

Powdered activated carbon (PAC) is increasingly applied in industrial wastewater advanced treatment. Flow characteristics in filtering element of PAC play a major role in improving the wastewater treatment efficiency. In this paper the physical properties of microporous structure are measured for two kinds of PAC with different particle diameters. A vertical filtering section in pipe is designed to conduct experiment of flow through PAC porous filtering element. In the test, the working pressure in the filtering section is controlled by altering rotation speed of the pump. The thickness of the PAC filtering layers are ranged from 2mm to 8 mm. The correlations of head loss to flow discharge in PAC filtering layer is figured out according to experiment data. Based on the fitting correlations, a dimensionless formula of local head loss coefficient of PAC filtering layer with Reynolds number up to1337 for various relative thickness of activated carbon layer is obtained. It is shown by analysis that when Reynolds number becomes large, the local head loss coefficient of PAC filtering layer is descended. Big relative thickness of activated carbon layer corresponds to large local head loss coefficient of PAC filtering layer. For small relative thickness of activated carbon layer, the flow rate of filtration obviously increases with activated carbon particle diameter.