Since July 1998 the Osaka Prefectural Government has been working to install an advanced water purification system at all of the purification plants it operates. The system eliminates the musty odor caused by eutrophication in Lake Biwa as well as preventing the inflow of domestic and industrial effluent to ensure safe, clean-tasting water for 41 cities, towns and villages in the prefecture. This advanced purification system supplements the standard water treatment processes of coagulation, sedimentation, sand-filtration and chlorination with three additional processes, namely biofilm treatment, ozone treatment and granular activated charcoal treatment. Advanced water purification systems may use ozone treatment alone or use a combination of two of the three above-mentioned treatment processes. Advanced water purification system Osaka Prefecture Microorganisms effectively eliminate ammonia nitrogen in water.
Ozone works to decompose trihalomethanes and substances that cause musty odors.
This system effectively eliminates trihalomethanes and substances that cause musty odors. Pollution levels monitored by the color of waste water Promoting the Hanshin Canal Project From general development to general conservation at Lake Biwa Wakayama City Wakayama City regulates liquid waste from the many dye works and chemical plants in the city by assessing the waste's color, turbidity, temperature and residual chlorine, a unique system for purifying public water supplies that is not used anywhere else in Japan. To measure color, for example, liquid waste is diluted with distilled water and compared with the distilled water until the two are indistinguishable in color. The color value is calculated according to how much the waste liquid has been diluted. This method has many advantages, including its ease of use, ability to be used with various types of waste, and ability to provide a numerical expression of the degree of color.