Patent ID: 7993532

Claim:
A method for treating water or wastewater by gravity using cloth filter media in a treatment basin having side walls and influent and effluent channels, including the steps of: introducing water or wastewater for filtration into the treatment basin; filtering the influent by gravity such that the influent flows through a stationary and substantially hollow cloth filter media support structure forming an effluent plenum which is positioned in the basin and to which is attached cloth filter media, said cloth filter media support structure having a length and two ends, one end being an open end mounted to and supported by a side wall of the treatment basin and in gravity flow fluid communication with an outlet of the treatment basin on a side wall of the treatment basin, and the other end supported by and mounted to an opposing side wall of the treatment basin, whereby the length of said support structure extends between opposing walls of the treatment basin and said support structure is fixed to and within said treatment basin; and, periodically cleaning said cloth filter media using a traversing backwash system including a self-aligning and linearly moving backwash assembly having backwash shoes external to said cloth filter media support structure for periodically cleaning said cloth filter media with suction, said self-aligning backwash assembly having a hinged rocker cage that is external to said cloth filter media support structure.