| In order to study the Chemical Oxygen Demand（CODMn） removal regularity in the wetland, indoor three stages, two stages and one stage downward flow simulated wetlands treating water of Qinghe River in Beijing were discussed. The results showed that the two stages planted system had the highest removal rate under the hydraulic load of 0.2 m3·m-2·d-1, and hydraulic retention time of 1.72 d, the average removal rate in operation period was 59.71%, with the average effluent concentration below the value of grade-Ⅱ standard of surface water. The stages of series connection had a superior effect on CODMn removal, the one stage systems and the multistage systems had significant difference in the CODMn removal efficiency（P<0.05）, but no obvious difference was observed for the multistage systems（P>0.05）. The plants had a significant effect on CODMn removal, the unplanted-planted corresponding systems had significant difference in the CODMn removal efficiency（P<0.05）, the planted systems and the column in flow pathway of multistage systems had a better CODMn removal efficiency in operation period. Considering the removal efficiency and the actual cost, we recommended the planted two stages series connection system. |
