Study On The Performance Of Short-cut Nitrification Combined With Different Anaerobic Ammonium Oxidation Systems For Treatment Of Mature Landfill Leachate

The landfill leachate produced by sanitary landfill is an organic wastewater which has high ammonia nitrogen and is complex with a large change in water quality.The commonly way to treat landfill leachate is unstable and cost high.The autotrophic biological denitrification system-short-range nitrification combined anaerobic ammonia oxidation（anammox） has the characteristics of low energy consumption,no need for external carbon source,and low sludge production,which can make up for the deficiency of traditional treatment methods.In this study,the mature landfill leachate was used as the research object,and short-range nitrification was combined with anammox ASBR system and anammox biofilter system respectively to treat landfill leachate,exploring the performance of two combined processes on system’s start-up,combined process treatment of landfill leachate and the microbial combination in anammox system.So the performance of the two combined processes was investigated in three aspects:the start-up time of each system,the treatment effect of different combined processes on landfill leachate,and the composition of strains in different stages of each system.The main findings are as follows:（1）The short-range nitrification system inoculated the domesticated sludge stored at low-temperature for long time,could quickly recover the activity within 7 days’ operation,and achieved semi-short-length nitrification by controlling the aeration time of 4⁶h and dissolved oxygen 0.3mg·L^-1.The anammox system is inoculated the sludge from the secondary sedimentation tank of the municipal sewage treatment plant.The start of the ASBR system took135 days.After 241 days of operation,the total nitrogen volume removal load of the system reached 0.147kgN·（m³·d）^-1;the biofilter system started for 114 days,after 215 days of operation,the total nitrogen volume removal load reached 0.570 kgN·（m³·d）^-1.Biofilter starts up faster and can quickly increase processing load by reducing hydraulic retention time.（2）During the combination of short-cut nitrification system and different anammox systems,the three systems can adapt to the leachate water quality in a short time.The total nitrogen volume load of the short-range nitrification and ASBR anammox system is 0.280kgN·（m³·d）^-1,and the total nitrogen volume load of the combined system with biofilter anammox can reach 0.550 kgN·（m³·d）^-1,so the load of biofilter treatment is higher and could adapt the fluctuating water quality.（3）The result of fluorescence quantitative PCR show that the proportion of anammox bacteria in the system became larger as the operating time increased;and the number of anammox bacteria was the biggest at 30 cm from the entrance.The result of high-throughput sequencing technology show that the started-up anammox systems had lot Planctomycetes,the dominant phylum,the functional strains of two anammox systems were Candidatus Kuenenia and Candidatus Anammoxoglobus,and a small amount of Candidatus Brocadia was also detected in the biofilter.After long-term treatment of leachate,Candidatus Anammoxoglobus and Candidatus Brocadia were eliminated,and Candidatus Kuenenia is more suitable for mature leachate treatment.This study aims to select an anaerobic ammonium oxidation system that is more suitable for the combined process by comparing the performance of the two combined systems,and provide a theoretical basis for the combined process to treat the aged landfill leachate for practical engineering.