Three plans(induction of water flow, supply of oxygen into water, control of fish causing resuspension of
solids) proposed to improve the pollutant removal efficiency of Sihwa Constructed Wetland(CW) were estimated by
considering the their efficiency and application to the wetland. After construction of facility for induction of water
flow in lower part(W 122m×L 103m) of the wetland, the mean removal efficiencies of BOD, SS, TN and TP were
in range of 12.8~37.4% and BOD was showing the highest efficiency. This result indicates that water flows is one
of very important factors in the pollutant removal of wetland, especially near the outlet of a large scale wetland
such as Sihwa CW. Dissolved oxygen(DO) concentrations after operation of two oxygen supply systems such as Air
Bubble Diffuser and Surface Aeration System increased 15.5% and 27.2%, respectively. For maintaining effective
DO concentration in Sihwa CW, the operation of oxygen supply system may be desirable during midnight to dawn
in the location in which DO concentration is not enough, for instance less than 2 mg/L in CW. In experiments of
the fish removal from Sihwa CW, the mean turbidity was lower in test site(6.2 NTU) than control site(10.6). The
removal efficiency of thurbidity by th fish removal from the wetland was 41.5%. Therefore, a relevant fish
management through a periodical monitoring of fish and turbidity is needed.
Keywords : Constructed wetland, removal efficiency, improvement plans, case study