Investigation of Treatment of Domestic Wastewater by Constructed Subsurface Wetlands

The purpose of this study is the use of subsurface flow constructed wetlands to treat domestic wastewater near Kuei-tzu-keng stream. Biofilm decompose on the surface is the primary removal mechanism. The gravel bed subsurface constructed wetland was used to investigate the removal efficiencies of SS, NH4+-N, BOD5, and PO43-.
Results showed the removal efficiency is optimum when HRT were 1day. The averages of removal rate of SS, NH4+-N, BOD5, and PO43- were 57.4﹪, 13.7﹪,29.8%, and 1.6﹪respectively. There was a significant correlation between removal efficiency and inflow concentration of SS, NH4+-N, and BOD5. However removal efficiency significant increase as the concentration was below 20mg/L in SS and 5.5mg/L in BOD5. Removal efficiency of phosphorus in this experiment is insignificant. To avoid clogging and anaerobic, the wetlands should dry after 120days treatment and lead to aeration for treatment.