Field Study of Suspended Solid Discharge from Combined Sewerage System of a Highly Urbanized Area

Abstract

The sewage coverage rate in Tokyo Ward has reached 100 %. However, 80 % of this coverage are combined sewer systems built before 1980. Consequently, large quantities of organic suspended solids are discharged from rainwater outlets into rivers during heavy rainfalls. Suspended solid (SS) pollutants accumulate in downstream brackish-water regions, giving rise to water quality problems such as floating scum, foul odors, and cloudy water. In this study, SS runoff characteristics were investigated in the Nomi River drainage basin with a combined sewer system using MIKE URBAN software to calculates sewer runoff. First, the overflow water depth and SS were measured at two sections located in the sewer system during two storm events. The parameters for MIKE URBAN were adjusted so that the observation results were reproduced well. Next, the model was applied to all outlets in the entire catchment of the Nomi River. The estimated discharge was input into a one-dimensional unsteady river flow model. Calculations satisfactorily reproduced observational results of the water level and turbidity measurements at the upstream end of brackish-water region not only for the two storm events but also for three other storm events which occurred after the model parameter calibration was completed.

The Investigation on Mineral Wool Performance as a Potential Filter to Remove TSS in Cikapayang River, East Jawa, Indonesia

“…Therefore, the increasing TSS concentration leads to increased pollution. This topic has received significant attention worldwide, such as Citarum River (Marselina et al, 2022), Elemi River (Folorunso, 2018), Nomi River (Miura et al, 2019), Pará River (Carneiro et al, 2020), Hau River (Nguyen et al, 2020), and Nakdong River (Kwon et al, 2021). Many experiments had been carried out in the laboratory simulating TSS removal in water streams.…”