Exploration Of Rapid Start-up And Operation Strategy And Pilot-scale Application Of Anaerobic Ammonia Oxidation For Leachate Treatment

Aiming at the problems of slow start-up and low denitrification efficiency of Anammox process in landfill leachate,the strategy of rapid start-up and steady operation of Anammox process in treating landfill leachate with high ammonia nitrogen and low C/N ratio was investigated.First,the effect of different sludge inoculation strategies on Anammox initiation was investigated to select the optimal sludge inoculation strategy.Subsequently,Comparison of the effects of different concentrations of N₂H₄on denitrification of Anammox in landfill leachate,combine the optimal sludge inoculation strategy with suitable N₂H₄concentrations to achieve rapid start-up and long-term stable operation of Anammox process in treating landfill leachate.The results of the small-scale research was further verified by studying the start-up characteristics of the pilot PN/DN-Anammox system when the optimum sludge inoculation strategies and suitable N₂H₄concentrations was applied to the pilot-scale work.At the same time,the engineering parameters of the pilot PN/DN-Anammox system were optimized for better denitrification performance.The results from the study aimed to provide rapid start-up and stable operation of the Anammox process,and to provide scientific technical support for future practical engineering applications.The main findings of this study are as follows:（1）The Anammox reactor was started with different inoculation sludge for100 d.It was found that inoculation of 10%Anammox granular sludge could rapid start-up Anammox reactor.The results showed that the Anammox process inoculated with denitrifying sludge:Anammox granular sludge=9:1 had the optimal start-up effect,and the TN removal rate could reach 75.1%at 100 d.（2）The appropriate amount of N₂H₄could weaken the adverse effects of high concentration of influent substrate and landfill leachate on Anammox,enhance denitrification of Anammox while inhibiting the activity of heterotrophic denitrifying,and to have a positive promotion effect on SAA and EPS secretion and Anammox bacteria reproduction,with the best promotion effect at 6 mg-L^-1N₂H₄concentration.And the average TN removal rate of the reactor dosed with 6 mg·L^-1of N₂H₄in landfill leachate was 90.6%,which was 28.9%higher than that of the reactor without N₂H₄addition,and It’s SAA was 0.143 kg-N（kg·d）^-1.EPS increased from 12.8 mg·g^-1to 33.9 mg·g^-1and Candidatus Kuenenia relative abundance increased from 0.2%to10.6%.（3）The Anammox pilot reactor was successfully started up with a sludge inoculation strategy of denitrification sludge:Anammox granular sludge=9:1 in 211d.Average removal rate of NH₄⁺-N NO₂^--N and TN reached 95.9%,78.0%and66.0%,respectively.Subsequently,Anammox activity inhibited by landfill leachate was restored by addition of 6 mg·L^-1N₂H₄,and NH₄⁺-N and TN removal rates were restored from 36.1%and 18.6%to 97.5%and 64.6%,respectively,The contribution of Anammox to nitrogen removal was 93.3%when Anammox pilot reactor was in stable operation.The microbial data showed that the volcanic rock filler was more effective in enriching Anammox bacteria,and the relative abundance of SM1A02 in the biofilm increased from 0.1%to 5.6%.