탄천하수처리장 유입수의 농도 증가 원인과 대책

Abstract

While Inflows into the Tan-cheon(River) Sewage Treatment Plant(STP) in 2001 were similar to those in 1999 and 2000, BOD concentration of the Tan-cheon STP in 2001 was increased from 103mg/L to 153mg/L and BOD loading to the plant in 2001 was enlarged from 90.1 t/day to 136.1 t/d. Both Weekly average and Sunday average were increased. Inflow during the first quarter of the 2001 was greater than those during 1999 and 2000. Possible reasons of the increase in BOD concentration in Tan-cheon STP can be represented as following aspects. First, recycling plant of food waste in Kangdong-Gu could cause a increase of BOD concentrations and loading rates. Because leachate from the recycling plant into Tan-cheon Interceptor sewer pipe cannot be collected, assessment was conducted on leachate into Nan-ji STP. As a results of assessment during April in 2001 and October in 2002, BOD concentration of the leachate was about 160,000mg/L. Because left bank of the Koduck-cheon(River) were suspected to discharge leachate of food waste, measurement of BOD concentration on the place was conducted. As a result of continuing measurement of BOD concentration for 24 hours on upward and downward 200m at left bank of Koduck-cheon BOD loading rate at those area in 2000. 6.28, 9.27, 12.20 were 3.2t/d, 6.2t/d, 8.4t/d, respectively. On the other side, BOD loading rate at the same place in 2001. 3.7, 6.8, 9.25, 12.12 were ranged from 21.9t/d to 49.8t/d. Second reason was separated sewer system of Daechi and Yangjae areas. population of these area were 84,527 and 50,894, respectively. calculated BOD loadings from those areas was 5.9t/d and it was 4.3% of the total BOD loading rate of the Tan-cheon STP, 136.1t/d. This result was determined by multiplying daily average municipal wastewater of 39,716m3/d by continually measured BOD concentration for 24 hours of 149.1mg/L.