A pre-filter is used to remove dirt, debris, and organic matter from the harvested water. This keeps the tank clean resulting in better water quality and less tank maintenance. The best way to filter the water is at the source. The better the filtration upstream, the less money/effort will be required for filtration downstream.
Most all filters work on an efficiency principle, which means that depending on flow rate, all or a portion of the water is filtered before entering the storage tank. Screen sizes can vary from 350 micron to 700 micron depending on actual filter. Larger units that collect water off a parking lot have larger screen openings and typically include a form of oil/water separation.
Some filters can be automatically cleaned (or flushed) by sending pressurized water from the pump station to a spray head located on the filter body. Flushes are initiated via a daily timer on the SkyHarvester control operator interface.
The above filters are two frequently used options in SkyHarvester systems. Each filter uses a stainless steel screen to prevent debris from entering the storage tank. These filters have a screen size of 350-700 micron and are self-cleaning / flushing units.
The above photo shows a complete SkyHarvester system installed at Coca-Cola Distribution in Lexington, Kentucky. Being a single-source supplier, our scope begins at the pre-filter upstream of the storage tank and ends the connection to the water distribution system. We integrate the pre-filter itself, storage tank(s), pump station, discharge and treatment, and the controls to operate the entire system seamlessly.
This close-up of pre-filtration at the University of Wisconsin, Milwaukee is located in a below-ground parking garage where water is filtered from seven stories above. It is then delivered to the below ground storage tank just on the other side of the concrete wall for landscape irrigation.