[Treatment Effects of Earthworm Constructed Wetlands in Different Working Conditions]

The feasibility of a new sludge treatment technology of earthworm constructed wetlands was tested by adding earthworm into the traditional sludge dying reed beds. The dewatering and stabilization effects of the upper layer sludge were tested under different sludge loading rates of 48, 65, 80 kg·(m²·a)^-1, different earthworm stocking densities of 0, 0.43, 0.54, 0.65 kg·m^-2 and different sludge loading frequencies. The results indicated that it was feasible to provide a shelter for earthworm during the loading period by setting a damper with a buried depth of 10 mm. The addition of earthworm could effectively improve the dewatering and stabilization effects of earthworm constructed wetlands, by lowering the DHA and decreasing the moisture content and VS of sludge by 15% and 10% respectively. The stabilization effects of earthworm constructed wetlands reached the best under the stocking density of 0.65 kg·m^-2. With the increase of sludge loading rate and decrease of loading frequency, the running efficiency of earthworm constructed wetlands would be worse.