Résumé
A combined process of multi-layer bio-filter and constructed wetland has been used to treat the rural sewage in eastern China, The capacity of the system was 60m(3)/d, the hydraulic loading rate (HLR) of the bio-filter and the constructed wetland was 4.0 m(3)/(m(3).d) and 0.50 m(3)/ (m(3).d), respectively. The system has been operated automatically for 2 years. The results showed that the average concentrations of COD, NH4+-N, TN and TP in the effluent were 58.2, 8.1, 12.1 and 0.9 mg/L with the removal efficiency of 79.2%, 62.8%, 55.1% and 77.1% respectively, which could meet the first grade of Chinese national pollutants discharge standard for municipal wastewater treatment plant (GB 18918-2002). The track studies showed that the organic pollutants were mainly removed in the first 4 layers and the ammonia was mainly removed in the 4(th) similar to 6(th) layers of the filter. It was observed that the COD removal efficiency in the whole system decreased from 84.6% to 73.3% following the sequences of summer, autumn, spring and winter. Comparing with traditional techniques, the combined process could provide a higher nitrogen and phosphorus removal capacity.