PURPOSE: To make the clogging of a filter membrane hard to generate even when river water is directly introduced and to miniaturize the whole of water purifying treatment equipment.
CONSTITUTION: Since a bacteria immobilized carrier 24 is provided in a circulation route, bacteria contained in raw water are immobilized on the surface of the carrier 24 and the inner surfaces of the pores thereof to be largely propagated thereon. Therefore, the concn. of bacteria in the circulated raw water becomes low and the clogging of a filter membrane caused by bacteria becomes hard to generate. Since suspended matter such as an org. substance is repeatedly passed through the bacteria immobilized carrier 24 during the circulation of raw water, it is gradually decomposed by bacteria on the carrier 24. Therefore, the clogging of the filter membrane 26 becomes hard to generate without performing pretreatment due to a large-scale biological contact tank and, as a result, even when raw water such as river water is filtered, the lowering of treatment efficiency is relatively reduced and equipment can be miniaturized.
KAMEI YUJI
YOSHIKAWA TAKASHI
