Abstract: A filter apparatus in which a generally horizontal bed of filter material is supported in a tank on a porous support above the bottom of the tank and is divided by spaced partitions into individual filter cells above the support and individual filter compartments below the support, and a carriage is mounted for movement along the filter bed and has a collector hood that moves along the top of the bed to collect backwash effluent therefrom and a backwash head arranged to direct backwash fluid into the compartments below the porous support to sequentially backwash the filter cells. A cell scavenging head is mounted on the carriage for movement along the filter bed and arranged to sequentially withdraw fluid from each filter compartment and down-flow scavenge and rinse the associated filter cell subsequent to backwashing of each filter cell.

Abstract: A filter apparatus in which a generally horizontal bed of filter material is supported on a porous support and is divided by spaced partitions into individual filter cells above the support and individual filter compartments below the support, and a carriage is mounted for movement along the filter bed and has an waste water pump and collector hood that moves along the top of the bed to collect backwash effluent therefrom and direct it to a waste water trough, and a backwash pump and backwash head arranged to direct backwash fluid into the compartments below the porous support. A flow measuring weir is associated with the waste water trough and the backwash pump is arranged so that its output can be selectively delivered to the waste water trough whereby the flow measuring weir can be used to measure both backwash and waste water flow rates.