System and method for uniformly distributing a fluid through a filter bed in a filter

An apparatus for filtering water or wastewater, said apparatus comprising:

• (a) a fluid distribution chamber for receiving and distributing one or more fluids;
• (b) an underdrain operably associated with said fluid distribution chamber for directing a washing liquid from said fluid distribution chamber into a filter bed, said underdrain including a plurality of fluid passageways through which the washing liquid from said fluid distribution chamber passes in route to the filter bed;
• and,
• (c) a plurality of inserts, each of said inserts being configured to be inserted into at least a portion of one of said plurality of fluid passageways, each of said plurality of inserts having a control orifice through which the washing liquid from said fluid distribution chamber passes in route to the filter bed, at least one of said plurality of inserts has a control orifice of a size different from a control orifice of at least one other of said plurality of inserts to reduce maldistribution of the washing liquid during washing of the filter bed.

A method of reducing maldistribution of a fluid through a filter bed in a filter, said method including the steps of:

• (a) performing an analysis to determine where each of a plurality of distribution members should be located in an underdrain of a filter to reduce maldistribution of a fluid passing through a filter bed;
• (b) providing an identifying indicia scheme having a plurality of identifying indicia where each of the plurality of identifying indicia represents a characteristic of a given distribution member that can be used to determine where the given distribution member is to be positioned based on said performing step;
• and,
• (c) providing a plurality of distribution members with each of said plurality of distribution members having the identifying indicia operably associated therewith corresponding to the identifying indicia scheme so that an individual can readily determine where in a filter each of the plurality of distribution members are to be positioned in the filter based on said performing step.

An apparatus for filtering water or wastewater, said apparatus comprising:

• (a) an underdrain for supporting a granular media filter bed;
• (b) a first set of distribution members operably associated with said underdrain, said first set of distribution members including at least two distribution members, each of said distribution members in said first set of distribution members having a first hydraulic characteristic;
• (b) a second set of distribution members operably associated with said underdrain, said second set of distribution members including at least two distribution members, each of said distribution members in said second set of distribution members having a second hydraulic characteristic;
• and,
• (c) a plenum operably associated with said underdrain, said plenum being configured to direct a fluid into each of said distribution members in said first set of distribution members and said second set of distribution members, said second hydraulic characteristic being different from said first hydraulic characteristic to compensate for pressure differences in said plenum adjacent said first set of distribution members and said second set of distribution members.

A system for use with a filter having a filter bed that is periodically subjected to fluids including a liquid, a gas and/or a combination of liquid and gas;

• said system comprising:
• (a) a distribution chamber for receiving and distributing one or more fluids, said distribution chamber including an inlet for receiving one or more fluids;
• (b) an underdrain for supporting a filter bed having at least one layer of filter media, said underdrain including at least one opening for receiving one or more fluids from said distribution chamber;
• and,
• (c) a distribution member fixed relative to said underdrain such that said distribution member does not move relative to said underdrain, said distribution member being configured to vary a hydraulic characteristic of said opening in said underdrain to compensate for pressure variances in said distribution chamber.