상향류 다층 생물반응조(UMBR)와 생물막(토양피복접촉산화법)의 이중슬러지(Dual sludge) 공법을 이용한 고도처리 개선
= Case Study on the Full-Scale Retrofit BNR system with UMBR(upflow multi-Layer bioreactor) and Aerobic Bio Film(Existing Contact Oxidation Facility Covered with Top-Soil) Using Dual Sludge