Air scour/backwash apparatus for celless traveling bridge filter

A filter system comprising a filter basin having a bed of filter media material therein;

• a filtrate channel proximate said basin;
• at least one tubular underdrain header in said bed and in fluid communication with said filtrate channel;
• a backwash pump having a backwash water supply conduit selectively engageable with said at least one underdrain header for supplying backwash liquid to said bed;
• a bridge movable along an upper end of said filter basin, said bridge carrying a backwash hood for movement along an upper surface of said bed;
• said hood having a backwash manifold therein in fluid communication with a second pump arranged to draw backwash waste water and debris out of said hood;
• and wherein said backwash water supply conduit includes means for aspirating air into said conduit at a location between said backwash pump and said bed.

A traveling bridge filtration apparatus including a tank having a pair of side walls, a pair of end walls and a floor defining a filter basin including a downflow filtration bed;

• a bridge adapted to travel across the top of the tank, said bridge supporting a backwash pump, a backwash hood and enclosed waste water removal manifold;
• a partition wall between said side walls forming a filtrate channel adjacent the filter basin for receiving filtered effluent from the tank and for supplying backwash liquid to said filtration bed via said backwash pump;
• an underdrain comprising a plurality of tubular headers extending in horizontally spaced relationship through said bed and in communication with said filtrate channel, each header being provided with a plurality of apertures along its length;
• and wherein said backwash pump is selectively engageable with each of said plurality of headers by means of a backwash supply conduit connected to a sealing shoe constructed to provide access to at least one of said headers, and further wherein said supply conduit incorporates a nozzle and an air supply port for aspirating air into the backwash liquid downstream of the backwash pump and upstream of said filtration bed.