Abstract

The method of cleaning porous ceramic filters with a backwashing apparatus comprising an accelerating circulation path and a unit for mixing accelerated water with high-pressure air can be implemented with compact equipment to achieve efficient cleaning. The pool water purifying apparatus and system that adopt this method of cleaning porous ceramic filters comprise a filtering system that uses the ceramic filters, a disinfecting unit and an adsorbing unit and, optionally, an ultrafiltration unit as an additional filtering unit, and are capable of removing not only bacteria but also viruses so that the water purified by this apparatus and system may be as clean as potable water. Such an extremely high efficiency of water purification achieved by the apparatus and system can be maintained over a prolonged period since both the filtering and adsorption means can be cleaned by backwashing. The purifying apparatus is compact but it can be made further compact and allows for simpler installation work if the individual units of purification are integrated into a unitary assembly. The purifying system permits the water in a plurality of pools having different water temperatures to be purified efficiently with a single unit of the purifying apparatus.