Abstract: A water treatment system with a backwashable precise prefilter unit includes a backwashable prefilter column installation and a five-channel ball valve. The five-channel ball valve connects the water supply with both ends of the backwashable prefilter column installation. The backwashable prefilter column installation may be composed of three filter columns arranged in series: the first packed with quartz sand, the second with Cu-Zn alloy, and the third with sintered microporous polyethylene. The five-channel ball valve has three different working positions, namely, a cleaning water position, a discharging water position, and a backwashing position. The useful life of this backwashable precise prefilter unit can be more than three years. This backwashable precise prefilter unit may be used for independent water cleaners, as well as the precise prefilter for different kinds of water treatment systems, such as reverse osmosis water treatment systems.

Abstract: A reverse osmosis drinking water treatment system with a backwashable precise prefilter unit includes a super precise filter, a pressure pump and its automatic control system, a reverse osmosis membrane (or a nano-filtration membrane), a pressure tank, a post filter, and a drinking water dispensing apparatus. In front of the super precise filter, there is an independent backwashable precise prefilter unit. This unit is composed of three filter columns: the first packed with quartz sand, the second with a Cu--Zn alloy of high purity, and the third with sintered microporous PE. A five channel ball valve connects the water supply with the backwashable precise prefilter unit, and then with the super precise filter. The five channel ball valve has three different working positions, namely, a cleaning water position, a discharging water position, and a backwashing position. The useful life of this backwashable precise prefilter unit can be more than three years.