Constructed Wetland System for Wastewater Treatment in Korean Rural Community

Abstract A field experiment of wetland system was performed from August 1996 to August 1997 to treat the domestic wastewater in Chon-Ahn, Korea. The wetland was a subsurface flow type and was consisted of sand and reeds. The theoretical retention time was 2.33 days and the flow was continuous. The performance of BOD, COD, SS, and T-P removal was satisfactory and consistent. The effluent concentrations of BOD and SS met the effluent water quality standards set in Korea for the treatment plant size of interest. However, the performance of T-N was not satisfactory and average removal rate was about 12%. Further research is recommended to reduce nutrients in the effluent. The variation of removal rates with flow distance showed that treatment zone of the first few meters from inlet were more active in reducing concentrations, and removal rates increased gradually thereafter. It implies that series of moderate size of treatment basins might perform better than a long treatment basin. The hydraulic loading rates affected the performance of BOD and COD, but SS was less affected. The effects of pollutant loading rates was not significant for the normal range of domestic wastewater treatment. The effluent concentrations of BOD, COD, and SS did not show much fluctuation while input loading rates varied significantly, which implies that buffer capacity of the wetland system can keep the effluent quality quite stable for normal situation. Overall, the results of the experimental wetland system was encouraging, and it can be considered as one of the practical alternatives for rural domestic wastewater treatment in Korea.