Filtration Cycles

• Service.  Filters remove solids from water.  The water flows downward through the media and is clarified.  The solids accumulate in the media bed.
   

• Backwash.  When the filter begins to clog or when the head loss though the bed increases, flow rates are dramatically reduced and often solids “break through“ the filter and water quality deteriorates.  To clean the filter bed, the flow is reversed, fluidizing the media bed, and is directed to drain.  The flow required is specific to the media.   If too much flow is applied, the bed can be flushed from the tank and if too little flow is applied, the bed will not fluidize properly and will not be cleaned.  Improper cleaning leads to mud ball formation and channeling in the filter. The FRF, FMF, and FHF Series all use nozzle type backwash rate-of-flow controllers. Backwash is made possible by shifting the Task Master^ä or Task Master II^ä multiport valve so that it allows the water to enter the bottom of the filter tank and flow upward through the media bed, thus backwashing filtered solids to drain.
   

• Filter to Waste.  When a filter is returned to service after backwash, the initial effluent solids concentration from the filter is high.  The bed must be repacked and begin to remove some particulates before it can become effective.  Thus, the first few gallons of a filter run are usually wasted.   This part of the cycle is called filter to waste.