장기운영을 통한 친환경 수처리 기술의 하천수 수질개선 효율 평가

Abstract

Eco-friendly water treatment technology is emerging as a countermeasure to improve the quality of river water and source water. Among various eco-friendly water treatment technologies such as subsurface flow (SSF) and surface flow (SF) wetlands, vertical flow constructed wetland (VFCW) which is one of the SSF wetland is being used in the Netherlands as post-treatment for decentralized sewage treatment plants due to greater cold tolerance than general SF wetlands. In addition, SSF wetlands are less affected by seasonal water temperature fluctuations than SF wetlands, so they have the advantage of providing stable water treatment. In this study, an eco-friendly water treatment test-bed was installed for evaluation of applicability on river water (Yeongsan river water) at near Seung-chon weir and was operated for more than one year. A VFCW with 0.4 m/d showed excellent treatment efficiency of 83.8% turbidity 83.8%, SS 95.6%, BOD 93.6%, and T-P 73.7% and showed low treatment efficiency of 33.8% TOC and 31.0% T-N. At 1m/day, the treatment efficiency was similar to 0.4m/day. However, in the case of 2m/day or more, the treatment efficiency tended to decrease somewhat as the filtration speed increased. In the seasonal evaluation, there was little change in treatment efficiency by season in most of the water quality items except for T-N. As a result of organic material characterization, the proportion of non-degradable organic matter in both accounted for most of 74.4~81.4%, resulting in a low treatment efficiency of about 5.7%.