Characteristics of Pollution Loads from the Combined Sewer during Dry Season

We have examined the pollutant load of combined sewer in dry days. Two monitoring sites (C-1, C-2) were equipped with an flowmeter. Monitoring was conducted from September 2004 to April 2006 for 20 months during dry days. Flowrate and concentration of pollutants are lowest from 3 to 6 o`clock, and it is high at 9, 12 and 21 o`clock. Most of organic matters exist in the dissolved state. The results show that pollution loads in C-2 area were 4.5-7.2 times higher than in C-1. Pollutant loads were high on Saturdays. Pollutant loads (kg/ha/day) of C-2 were 1.1-3.1 times higher those of C-1. However there was no significant difference in winter. Analysis of correlation coefficient of water quality parameter indicates that besides of flowrate all items in C-1 site have tight relationship respectively (p