STUDY ON HYBRID SOIL PACKING VERMIFILTRATION FOR TREATMENT OF DOMESTIC SEWAGE

The experiment adopted a dual-stage hybrid soil packing vermifiltration to evaluate the removal efficiencies of various pollutants in wastewater． The results demonstrated that when the vermifiltration operated for 90 days continuously，the removal efficiency of multistage earthworm ecofilter on COD，TP，NH3 － N，TN and SS was 78. 7%，93. 4%，74. 9%， 60. 4% and 87. 5% respectively． And the effluent quality met the level Ⅱ standards of“Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant”( GB 18918—2002) ． The design of vermifiltration with secondary structure improved the stability of sewage treatment and the quality of final effluent． The earthworms adapted the vermifiltration well at the early stage． The quantity and average weight of the earthworms increased obviously，indicating that the earthworms had good adaptability，growth and reproduction in vermifiltration，which could ensure the stability of vermifiltration． This technology has advantages of simple process，good treatment efficiency，environment friendly，low investment and flexible scale，thus possessing good application prospect．