Wetland model study of plant rhizosphere microorganism in the treatment of sanitary wastewater

The degradation effect of adding rhizosphere microorganism artificially on the COD of sanitary wastewater based on wetland models was studied in the experiment. Two rhizosphere bacteria isolated from the constructed wetland were mixed with a certain proportion of wastewater and injected into the wetland model. The COD degradation of wastewater was examined at 12h, 24h, 36h, and 48h respectively. The experiment lasted for two months in the spring, in which the changes of bacteria number and clogging status of the wetland substrate were investigated. The COD degradation ratio of the bacteria model was significantly higher than that of the control model (P<0.05), and the difference was even greater along with the time. The 48h COD degradation ratio for sanitary wastewater in the control model and the two bacteria models (hereafter model 1 and model 2) was 50.6%, 73.0% and 75.3% respectively. Moreover, the result of substrate permeability experiment showed that the infiltration duration of the control model is 28% longer than that of the bacteria model. The above experiment results implied that adding rhizosphere microorganism artificially may improve the COD degradation ratio of sanitary wastewater in wetland, and alleviate the wetland clogging significantly. Based on these experiment results, further work should be oriented to exploit the technology.