[Factor optimization for municipal domestic wastes treatment by earthworms and its concentration of heavy metals]

Simulated experiments, plot tests and applied stuties were conducted to determine the effects of the composition of municipal domestic wastes, their softening and culturing methods, and circumstance temperature on the treatment of municipal domestic wastes (MDW) by earthworms. The results showed that the decomposition rate of MDW and the multiplication rate of earthworms could be elevated by enhancing the C/N ratio of MDW, softening it with earthworms excrements, and culturing with indoor layer at 20 degrees C. Meanwhile, the treatment of MDW was also improved by the hybridization of tamed Chongqing Aisenia foetida and Caliginsoa. The concentration coefficient of heavy metals had no correlation with intenerating method, but were depended upon the types of heavy metals and the culturing method. Arsenic and cadmium were the most easily concentrated, while mercury oppositely. The concentration element in ridge culture was more easily than that in layer culture, and the concentration element in outdoors culture was more easily than that in indoors culturing.