Effects of Plant on Pollutant Removal Rate n Surface-flow Constructed Wetlands

Abstract

Three different types of wetlands (unplanted wetland, reed planted wetland, cattail planted wetland) were constructed at the mouth of Seokmoon reservoir with 910 m 2 each to examine the effects of wetland plant on pollutant removal rate in constructed wetland, and operated for 9 years (2002～2010). Water depth of the wetland was maintained at 0.3～0.5 m, flow rate was about 40～200 m 3 /day, and retention time was managed at about 1～5 days. There was no difference in removal rate of SS, TN, and TP between reed wetland and cattail wetland. Removal rate of SS and TN in planted wetland with reed and cattail were higher than unplanted wetland, whereas removal rate of TP in unplanted wetland was higher then planted wetland. The monthly variation of removal rate in planted wetlands was high compared with unplanted wetland. From the long term monitoring results, SS and TN removal rates of period3 (2008～2010) were higher than period1 (2002～2004) in planted wetland, whereas TP removal rate was decreased as time goes on. Overall, pollutant removal rate in constructed wetland was more influenced by existence of plants than by plant species. Although constructed wetland is operated long term period, SS, TN, and TP removal rate (SS 90 %, TN 60 %, TP 40 %) can be maintained high values.