1. Field of the Invention
The present invention relates generally to the field of swimming pool filtration. More specifically, the invention comprises a method for reclaiming an reusing most of the water used to “backwash” a pool filter.
2. Description of the Related Art
Swimming pools generally include a filtration system for removing contaminants. The pool water is forced through such filters for a substantial part of each day. One common form of filter is a sand filter. A sand filter is formed by partially filling a pressure vessel with sand filtration media. Pool water is forced through the filtration media and the sand traps the unwanted contaminants.
As the filtration media becomes more saturated with contaminants, the pressure differential across the filter rises. The filter is in effect becoming clogged by the contaminants it is designed to remove. Water flow is progressively reduced by the clogging of the filtration media and the filter becomes progressively less efficient. The filtration also tends to aggregate resulting in the formation of water “tunnels” that allow flow to pass through the media without being effectively filtered. In order to eliminate this problem, a sand filter must periodically be “backwashed.”
“Back washing” generally refers to the process of reversing the flow through the filtration media in order to stir the media and remove the trapped contaminants. Air injection may be added during the backwashing process to lift the filter media off the bottom of the pressure vessel and promote agitation. The water carried through the filter during backwashing is dumped out of the recirculating pool filtration system through a “backwash line.” This water is often discharged onto a lawn area surrounding the pool. It may also be dumped into a sewer line. In any event, the dumped water contains undesirable contaminants. It contains the particles the sand filter is intended to remove. It also often contains chlorine and other potentially harmful pool chemicals.
There is an increasing recognition that backwash waste water should not be dumped into the area surrounding a pool nor into the sewer system serving the area. Some regulating authorities are now passing rules prohibiting such dumping. Thus, there is a need for a system which reduces the unwanted dumping of backwash waste water. The present invention proposes such a system.