Tertiary filter

Abstract

A filter cloth of long pile fiber bundles is used as a tertiary filter in a wastewater processing method. The filter may be backwashed by a rotating suction head which does not touch the filter cloth. A combination of countercurrent and horizontal flow dislodges entrained solids from the filter cloth. Mounting of the filter media as modular components permits increased capacity within a single tank while avoiding down time in changeover of filter media.

1 - 21 . (canceled) 
     
     
         22 . A modular filter assembly comprising a peripheral frame, said peripheral frame defining an outlet for filtered wastewater at an upper end thereof;
 a first supporting backing plate attached to said peripheral frame to form a front face; and a second supporting backing plate attached to said peripheral frame to form a back face of said modular filter assembly;   said first backing plate forming said front frame being covered with a first filter media;   said second backing plate forming said rear frame being covered with a second filter media;   the first and second filter media; in combination with said peripheral frame defining an enclosed space into which filtered wastewater can accumulate;   said outlet being in fluid communication with said enclosed space into which filtered wastewater can accumulate.   
     
     
         23 . The modular filter of  claim 22 , wherein the first and second filter media each comprises a plurality of fiber bundles attached to a foraminous backing. 
     
     
         24 . The modular filter of  claim 22 , wherein the peripheral frame further comprises a track which is sized and shaped so as to be receivable by channels mounted in a tank for receiving wastewater. 
     
     
         25 . A tank for receiving wastewater comprising a modular filter according to  claim 22 . 
     
     
         26 . The tank of  claim 25 , comprising a plurality of the modular filter according to  claim 22 . 
     
     
         27 . A tank for receiving wastewater, the tank comprising a plurality of channels, said channels being sized and shaped to receive the modular filter according to  claim 22 . 
     
     
         28 . The tank of  claim 27 , wherein the channels are sized and shaped to permit the peripheral frame of the modular filter elements to be slidingly engaged by, and slidingly removed therefrom. 
     
     
         29 . The modular assembly of  claim 22 , wherein the peripheral frame further comprises tracks. 
     
     
         30 . The modular assembly of  claim 22 , wherein at least one of the first and second backing plates comprises a material selected from the group consisting of metal and plastic. 
     
     
         31 . The modular assembly of  claim 30 , wherein the backing plate comprises a grid. 
     
     
         32 . The modular assembly of  claim 31 , wherein the filter media is stretched over the grid and attached at points intermediate its periphery. 
     
     
         33 . The modular assembly of  claim 31 , wherein the filter comprises a plurality of fiber bundles attached to a fabric backing. 
     
     
         34 . The modular filter assembly of  claim 22 , further comprising a lifting hook attached to the peripheral frame.