CASE STUDY ON EVALUATION OF FUNCTION OF URBAN DRAINAGE TREATMENT FACILITY

Abstract

This study evaluated the function of a model treatment facility for drainage from an urban area.The facility, which is located in Kusatsu-city, Shiga Prefecture, is a multiple treatment facility for storm water runoff and consists of storage and sedimentation tank, contact aeration tank, vegetation bed, and soil penetration tank. The removal efficiency of pollutants in each of these four components of the facility was investigated quantitatively. Focusing on unit cost for pollutant load reduction in terms of T-COD, T-N and T-P, cost benefit analysis for sewerage works was undertaken to facilitate overall evaluation of the facility.