Experimental Study On The Treatment Of Landfill Leachate By Improved MBBR Partial Nitrification And UASB Anaerobic Ammonium Oxidation Process

At present,the excessive leachate produced by burying and incineration of garbage is a serious problem that plagues the environment.Biological method is still considered to be the most common method of disposal of landfill leachate due to its high treatment efficiency and relatively low operation and maintenance costs.And will not cause secondary pollution of sludge,and is favored by landfills and incinerators in various countries.Anaerobic ammonia oxidation（ANAMMOX）has attracted much attention as a research focus in recent years.Because it does not require an external carbon source and has a low sludge output,it has become the future direction of biological treatment.However,the water inlet conditions are harsh and the cultivation period is long.At the same time,the emergence of partial nitrification provides a stable feedwater matrix for anammox.Based on this,this thesis studies a MBBR（moving bed biofilm reactor）and UASB（upflow anaerobic sludge bed reaction）.The combined two-stage partial nitrosation-anaerobic ammonia oxidation process is used as a treatment plan for landfill leachate.And explore the application of the improved MBBR under a new packing layout scheme in the experimental stage,and realize the combined operation of MBBR partial nitrosation and UASB anaerobic ammonia oxidation by controlling various parameters.The improved MBBR adopts reasonable arrangement of K3 fillers and combined fillers to achieve partial nitrosation in a short period of time（39d）,the nitrite accumulation rate（NAR）reached 84%,and the contribution rate of K3 fillers to the ammonia oxidation rate（AOR）during the stable film formation period Above 70%,the nitrogen load（NLR）is maintained at（0.33±0.01）kg/(m³·d^-1).Adjust the stop-exposure ratio of MBBR to 1:1,1:2and change to continuous aeration.The analysis of EPS shows that PN and PN/PS first increase and then decrease during intermittent aeration,and the sludge settlement performance becomes worse,so stop the exposure.When the ratio is 1:1,the nitrate oxidation rate（SNOR）is lower than that of the nitrate oxidation rate（SNOR）.The PN/PS value of continuous low oxygen aeration can reach 1.76,which is more beneficial to the formation of granular sludge.UASB inoculation starts anaerobic ammonia oxidation,the sludge inoculation rate is10%,NLR can reach（0.86±0.01）kg/(m³·d^-1)after 147 days,and the removal rates of NH₄⁺and NO₂^-also exceed 83%and 99,respectively.The 150-day unit is operated in combination,and the initial TN removal rate is maintained at 72%.The UASB reactor under high nitrogen load cultivation can have a certain adaptability to irregular NO₂^-/NH₄⁺inflow.This adaptability will gradually weaken in the short term.Long-term unstable water intake will cause anammox instability.After adjusting the NO₂^-/NH₄⁺value of UASB influent for 30days,the TN removal rate recovered to 69%,and the nitrogen removal load（NRR）increased to 0.22 kg/(m³·d^-1).The nitrosation state of long-running equipment deteriorates,and the increase of biofilm thickness leads to the growth of anammox bacteria.Controlling temperature,p H and restarting of traditional MBBR inhibits anammox bacteria from recovering part of the nitrosation.The results show that the single control temperature The NAR can be increased to24.8%at（30±0.5）℃,and the partial nitrosation is further restored under the control of multiple factors.The p H is about 8.1.The K3 filler is stirred by the electronic stirring device from the air lift type,and the NAR is restored to 35.9%,which deteriorates.After the partial nitrosation can’t be restored to the start state.