Filtering and purifying system

摘要

In a filtering and purifying system, bacteria in raw water are sterilized efficiently with ultraviolet rays, chemicals and the like at a pretreating step. The number of microorganisms such as bacteria remaining in the treated water is reduced remarkably, and the residue of plankton and organic substances as nutrients for bacteria in treated water is reduced by a coagulating and filtering treatment. It is thus possible to solve a problem that the treated water is deteriorated with time due to propagation of the bacteria.