오존(O3)․입상활성탄(GAC) 공정을 이용한 맛․냄새 유발물질과 유기물질의 제거특성 평가

Abstract

This study assessed the removal characteristics of taste and odor causing compounds (2-methylisoborneol and geosmin) and organic matters, using a pilot-scale ozone/granular activated carbon (O3/GAC) process treating surface water of Pal-dang reservoir in the Han river over a 3-month period. Experiments were conducted to verify the removal efficiency of O3/GAC process which has two different empty bed contact time (EBCT) (O3/GAC column 1 : 10 min and 2 : 15.1 min) with 10.86 min contact time of ozonation at 1.0 mg/L O3. Spiking test using geosmin and 2-MIB was also conducted systematically to mimic the conditions when the algae appears, specifically at the levels similar to the concentrations experienced (geosmin: 250 ng/L) in the winter of 2011. In single ozonation process, organic materials, disinfection by-products (DBPs) and their precursors were disassembled but not removed completely. Meanwhile, it was verified that organic matters, taste and odor causing compounds, and DBPs were well removed when sequentially passing through the GAC process. The pilot results also showed that GAC column with larger EBCT achieved higher removal efficiency. Specifically, in spiking tests, single O3 process showed approximately 89% removal efficiency of geosmin and 2-MIB. O3/GAC combined process demonstrated excellent removal of geosmin and 2-MIB, which are higher than 95%.