Pre-Coat Filter

Pre-coat filters use a filter aid medium, usually a diatomaceous earth (DE) slurry which is put on a coarser support medium and used (Figure 8) to remove very small particulate matter. DE filters can remove particles down to 5 microns and below, including some removal of protozoa and even bacteria. The medium must be changed frequently and presents a waste disposal problem. Pre-coat filters are most practical for limited volume applications and are common for swimming pools, beverage plants, and certain industrial applications.