Old landfill leachate treatment and bacterial community analysis

摘要

Aged refuse reactors were constructed to simulate landfill leachate degradation process in the lab at different hydraulic loadings and temperatures. The results showed that aged refuse biofilter could remove CODcr, BOD5, NH4＋-N, TN and TP of leachate effectively at hydraulic loading of 20 L/m3.d. The pollutant removal rate was low when hydraulic loading doubled. The average removal rate decreased sharply when temperature changed from 20°C to 10°C. Effluent recirculation could alleviate temperature effect on pollutant removal, which suggested that the recirculation of landfill leachate through aged refuse bioreactor is an effective strategy to decontaminated pollutants in winter. Pilot scale experiment showed that combined aged refuse biofilter and slag biofilter could treat mature landfill leachate efficiently. The bacterial community analyzed by pyrosequencing technique indicated that bacteria from Pseudomonas, Lysobacter, Bacillus and δ-proteobacter, Flexibacteraceae were dominated in the samples. Diversity, evenness and equitability were higher in the high hydraulic loading reactor. The Shannon index decreased at lower temperature, while evenness and equitability increased slightly in reactor with recirculation. Filter medium and temperature were main factors for shaping bacterial community structure.