Based on the actual situation of our country, this research focused on a new sewage treatment system (Two-stage Earthworm Rapid Infiltration Treatment System) which has some advantages in efficiency, economy and ecology. The contens of this study include: filter mediums' pollutants removement and its suitable combinations; the feasibility and the function of earthworms in the system; the system's treatment performance both for sewage and sludge; factors that affect the treatment efficiencies; the sy...