Patent ID: 8778174

Claim:
An apparatus for treating water or wastewater comprising: a) a vessel having a floor and walls defining a cloth filter zone comprising one or more cloth filter cassettes positioned substantially vertically therein, at least one cassette removably positioned in respective vertical cassette guide members; and b) at least one cassette having associated therewith at least one backwash assembly fluidly connected to at least one backwash header positioned to one side of the cassettes, at least one backwash assembly comprising a backwash arm positioned adjacent at least one main filter surface of the one or more cloth filter cassette, the backwash arm slideable in respective backwash arm guide members and dimensioned to backwash substantially all of a main filter surface; wherein the backwash assembly is driven by a drive assembly, the drive assembly comprising a set of screw jacks, a first drive shaft connecting two screw jacks, and a second drive shaft connecting two other screw jacks, each drive shaft also connected to a first bevel gear, which in turn connects through a third drive shaft to a worm gear motor, the second drive shaft connected to a second bevel gear which in turn connects through a fourth drive shaft to the worm gear motor.