Study On Treatment Of The Landfill Leachate With Complex Microorganisms

Because the landfill leachate’s composition is complicated, it’s volume unable to control and easy to cause secondary pollution, conventional biochemical processes is difficult to fit the national discharge standard. Being a new efficient process and the unique superiority, complex microbial technology has a very broad prospects in the leachate treatment.Exploratory experiments were carried out to treat leachate of Nanjing Lishui County sanitary landfill leachate site by complex microorganisms, using the biological diversity and combined effect as the indexes. Factors as the landfill leachate’s pH, reaction time, aeration time and dosage were changed to analyze and study the influence of complex microorganisms, taking concentrations of the organic matter, NH3-N, TP and COD as the evaluation index. Orthogonal test was designed to optimize reaction conditions of complex microorganisms. Single flora was screened from complex microorganisms, and their effects on landfill leachate were analyzed. Mixed complex microorganisms and single flora were used to treat landfill leachate, analyzing the effects of changing the proportion of single flora in mixed treatments. The experiment will provide the basis for complex microorganisms’ optimization. Using different concentrations of waste water the feasibility of treatment by complex microorganisms was studied.Single-factor experimental results showed that the optimum dosage range of Vbacteria/Vwater was1/5000to1/2000, the optimal reaction time range was48h to60h, the optimum aeration time range was36h to48h, and the optimum pH range was7.5to8.5. Through orthogonal experiments, the optimum reaction conditions were determined as following: dosage Vbacteria/Vwater1/2000, reaction time48h, aeration time36h, pH8. According to analysis of variance, the influence of factors, which affected NH3-N, should be in following order:aeration time> reaction time>pH> dosage; to TP:aeration time> reaction time> dosage>pH; to COD:aeration time> reaction time>pH> dosage; to complex microorganisms BM:aeration time> reaction time> pH> dosage.The result of single flora tests showed that photosynthetic bacteria and actinomycetes could remove organic matter, total phosphorus and ammonia nitrogen of the landfill leachate. Lactic acid bacteria have a certain effect on the removal of organic matter. Yeast had no effects on the organic matter removal, total phosphorus and ammonia nitrogen.The result of mixed tests showed that the maximum removal rate of COD was68.92%when the landfill leachate was treated by complex microorganisms, photosynthetic bacteria, actinomyces and lactic acid bacteria. The maximum removal rate of NH3-N and TP were89.06%and89.47%, respectively, when the landfill leachate was treated by complex microorganisms, photosynthetic bacteria and actinomyces. When the lactic acid bacteria proportion was increased in complex microorganisms, the removal abilities of complex microorganisms on NH3-N and TP were inhibited. When the yeast proportion was increased in complex microorganisms, it will inhibit the removal abilities of complex microorganisms on NH3-N, TP and COD were inhibited. Therefore the increments of proper proportion of photosynthetic bacteria and actinomycetes could improve the removal ability of COD.Complex microorganisms has a good process ability to treat different concentrations of sewage.