VARIATIONS OF PHOTOSYNTHETIC ACTIVITY AND GROWTH OF FRESH-WATER ALGAEACCORDING TO OZONE CONTACT TIME IN OZONE TREATMENT

The activity of freshwater algae in drinking water supply at various o zone contact times was investigated to evaluate ozonation used for ste rilization of algae. O-2 production rates of algae just after ozonatio n were severely retarded even by short ozone contact. The algal growth rate was also declined with increase of ozone contact time and comple tely inhibited by ozonation for 60 min. These results implied that the usual treatment time applied in conventional ozonation processes is n ot sufficient but at least 60 min of ozonation is required for a compl ete sterilization of freshwater algae in drinking water source.