서울시 하수처리장(물재생센터) 유입량 감소원인 분석

Abstract

influent of 4 sewage treatment plants(STPs) located in Seoul decreased by 864×103㎥/day during last 7 years(1998~2004). Among these plants, the influent in Jungnang STP showed the largest decline by 564×103㎥/day; 41, 119, and 140×103㎥/day in Tancheon, Seonam and Nanji STP, respectively. To analyze the causes of decreasing influent, investigation was conducted on the tap water consumption rate, groundwater consumption rate, groundwater flow produced from subway station, and infiltration/inflow(I/I). As a result, I/I was the main factor of reduction of influent to STPs. The rehabilitation of public and private sewers caused the reduction in infiltration and inflow of Jungnang, Tancheon, Seonam and Nanji subareas by 90, 20, 67 and 45×103㎥/day during last 7 years. These reduced amount in each subarea corresponded to 16.5%, 42.2%, 39.8% and 36.5% of totally reduced I/I. The interceptors of Jungnang, Tancheon, Seonam and Nanji subarea had been extended by 24.8㎞, 8.8㎞, 1.8㎞, 2.5㎞, respectively. The construction extending the interceptors in Jungnang subarea was implemented 2.8 times to 13.8 times as much as it was in 3 other subareas. It was concluded that the rehabilitation of the interceptors makes the most impact on the reduction in I/I.