High-rate filtration with a synthetic compressible media

An innovative filter that uses a synthetic, porous filter media was tested for more than 2 years at the University of California at Davis. The filter is unusual in a number of ways: (1) the synthetic filter media is highly porous (89%), (2) filter media and bed properties can be modified because the media is compressible, (3) the fluid to be filtered flows both around and through the media instead of only flowing around the filtering media (as in granular media filters), (4) the fluid that is filtered is used to backwash the filler, (5) to backwash the filter, filter bad volume is increased mechanically, and (6) the filter operates at high filtration rates (e.g., 410 to 1230 L/m(2).min [10 to 30 gal/min/sq ft]). Performance of the filter, with respect to removal of turbidity and total suspended solids, is similar to the performance of other more conventional filters with the exception that filtration rate is more than 3 to 6 times the rate of other filters. Also, percent backwash water required is significantly less than that used in conventional filtration technologies (typically 2 to 3% versus 6 to 15%).