METHOD FOR PURIFYING SEAWATER USING IMMOBILIZED NITRIFYING BACTERIA

摘要

PURPOSE: A method for purifying seawater using immobilized nitrifying bacteria such as nitrosomonas and nitrobacter is provided to recycle seawater for use in an aquarium or a fish basin, thereby japanese restaurants preparing sliced raw-fish dishes in inland areas far away from coastal area can reduce maintenance costs required for replacing seawater of an aquarium or a fish basin. According to this invention, conventional nitrifying bacteria mainly used for the removal of ammonia in freshwater are immobilized by PVA-Boric acid method, and then accommodated to saline water environment. CONSTITUTION: The method comprises the steps of an immobilization step(20) in which immobilized nitrifying bacteria(60) are obtained by mixing saturated boric acid solution with an admixture comprising 30% of polyvinylalcohol and 4-5g/L of nitrifying bacteria concentrate at the volume ratio of 1 to 1; an activation recovery step(30) in which ammonia solution of 5 to 45mg/L flows into an air-lift bioreactor(4) that is packed with immobilized nitrifying bacteria by 10 to 20vol.% in stages for 18 to 20 days; a saline water accommodation step(40) in which ammonia solution of 8 to 12mg/L flows into an air-lift bioreactor(4) that is packed with immobilized nitrifying bacteria that are activated in the activation recovery step by 10 to 20vol.% in the condition of 11 to 13 hours of HRT(Hydraulic Retention Time) and 30 to 40 days of reaction time; a nitrifying step(50) in saline water in which saline water containing ammonia flows into an air-lift bioreactor that is packed with immobilized nitrifying bacteria that are accommodated to saline water by 10 to 20vol.% in the condition of 1 to 3 hours of HRT.