Influence of alternate operation on clogging in a vertical-flow constructed wetland
轮休措施对堵塞型垂直潜流人工湿地的影响

The improvement of filtration in vertical-flow constructed wetlands by alternate operation was analyzed quantitatively. The effects of the alternate operation on pollutant removal, as well as the influence on plant growth, were studied. The research findings indicate that alternate operation is effective in resolving clogging in the vertical-flow constructed wetlands. The content of unfilterable material in the substrates is reduced by using alternate operation measures. The reduction in both unfilterable organic and inorganic materials is very obvious by using long term alternate operation measures. However, the amount of reduced unfilterable inorganic material is basically unchanged if a short alternation period (1d or 2d) is used. By using short term alternate operation measures, the removal rate of COD, TP and TN will be reduced and the removal rate of ammonia will be increased. To ensure that the alternate operation measures do not hinder plant growth in the vertical-flow constructed wetlands, the cycle time and methods of alternate operation should be taken into consideration according to the types of substrates treated and plants present.