Abstract:This paper aims to construct a composite vertical flow constructed wetland, with the optimal operation conditions for the system operation to be obtained by single factor and multi-factor orthogonal experiments. Under the optimal operation conditions (optimal operation condition of micro-dynamic aeration is that the aeration position is 60 cm down flow wetland, with 3.5 h the aeration time, 600 ml / min the aeration amount, the aeration mode being continuous aeration for 0.5 h and shutdown for 1.0 h.), an investigation has been made of the influence of the system on DO, pH, COD, NH4+-N, TN concentration in the system, as well as the operation effect of the composite vertical flow constructed wetland system. The results show that under the optimal operating conditions, the DO concentration of the effluent is 7.89 mg/L, the pH value 7.26, and the removal rates of COD, NH4+-N and TN reaching more than 90%. The effluent concentration of NH4+-N meets class I standard of the surface water, and the effluent concentration of TN meets class II standard of the surface water. The removal rates of NH4+-N, TN and COD in micro-polluted water by the wetland system CW1 are over 90%, significantly higher than that of the wetland system CW1 and CW2 in the blank control group. Through micro-dynamic aeration, the denitrification effect of compound vertical flow constructed wetlands on micro-polluted water sources can be significantly enhanced, with the removal rates of COD, NH4+-N and TN in the wetland system greatly improved.