Effects of Installation of Water-saving Devices on the Performance of Johkasou

Abstract

 Effects of water-saving devices on domestic wastewater treatment facility, Johkasou were investigated. After installing all water-saving devices such as toilet bowl and washing machine, water consumption decreased by 22%, and increase in BOD concentration in domestic wastewater was observed. In connection with the changes of influent characteristics, effluent BOD concentration of Johkasou increased from 14.8 to 21.4 mg/L. However, effluent BOD load which was calculated by multiplying BOD concentration and water flow volume, showed no increase because of the decrease of water volume. In the range of water-saving efficiency up to 22%, it was found that treatment performance of Johkasou did not turn worse. Furthermore, effluent BOD load decreased by 24.8% when aerobic-anaerobic circulation was conducted in Johkasou.