Abstract: A filter system having a filter bed for filtering water or wastewater, where the filter bed is periodically washed between service runs by directing washing liquid and washing gas upwardly through the filter bed. The filter system includes a filter bed and at least one flume. The flume is in fluid communication with the filter bed. Preferably, the flume is configured such that no washing liquid and washing gas interface is present in the flume. The flume may be configured such that during washing of the filter bed between service runs the flume receives a washing gas and directs the washing gas upwardly through the filter bed to assist in cleaning the filter bed between service runs. The flume may further be configured such that during washing the only liquid directed from the flume to the filter bed is residual liquid that may be present in the flume from a prior service run.

Abstract: A filter system having a filter bed for filtering water or wastewater, where the filter bed is periodically washed between service runs by directing washing liquid and washing gas upwardly through the filter bed. The filter system includes a filter bed and at least one flume. The flume is in fluid communication with the filter bed. Preferably, the flume is configured such that no washing liquid and washing gas interface is present in the flume. The flume may be configured such that during washing of the filter bed between service runs the flume receives a washing gas and directs the washing gas upwardly through the filter bed to assist in cleaning the filter bed between service runs. The flume may further be configured such that during washing the only liquid directed from the flume to the filter bed is residual liquid that may be present in the flume from a prior service run.

Abstract: A filter system having a filter bed for filtering water or wastewater, where the filter bed is periodically washed between service runs by directing washing liquid and washing gas upwardly through the filter bed. The filter system includes a filter bed and at least one flume. The flume is in fluid communication with the filter bed. Preferably, the flume is configured such that no washing liquid and washing gas interface is present in the flume. The flume may be configured such that during washing of the filter bed between service runs the flume receives a washing gas and directs the washing gas upwardly through the filter bed to assist in cleaning the filter bed between service runs. The flume may further be configured such that during washing the only liquid directed from the flume to the filter bed is residual liquid that may be present in the flume from a prior service run.

Abstract: A filter system for filtering water and/or wastewater which includes an underdrain system having a plurality of laterals that are anchored to the floor of a filter by a hold-down assembly. Preferably, the hold-down assembly does not rely on grout or other substance that is applied in a viscous or semi-viscous state and subsequently hardened as the primary means for connecting the underdrain laterals to the floor of the filter. Preferably, the hold-down assembly includes hold-down clips that can move relative to an anchor assembly and corresponding underdrain blocks so that the hold-down clips can cooperate with any desired portion of the corresponding underdrain blocks.