Research on the Improving Effect of Adding Earthworm to Vertical Flow Constructed Wetland for Rural Sewage Treatment

摘要

A vertical flow constructed wetland was built by adding Eisenia foetida.Pollutants removal characters of the earthworm constructed wetland were compared with the control of constructed wetland.Also,spatial distribution of microbial biomass and improvement of the anti-clogging characters after adding Eiseniafoetida were discussed.The research results showed that the earthworm constructed wetland could improve the removal effect of the pollutants.Comparing with the control of constructed wetland,COD,NH4+-N,TN and TP removal rates of the earthworm constructed wetland were increased by 15.8％,21.4％,19.7％ and 16.2％,respectively.Adding Eiseniafoetida could increase the biomass in each layer of the wetland.In the surface layer,in which the Eiseniafoetida were active,the total number of bacteria,nitrite bacteria,nitrate bacteria and denitrifying bacteria were 2.3,2.9,2.0 and 2.1 times of the control group.Clogging problem could be eased at the same time.