The Study On Landfill Leachate Treament By CANON Process Based On Tourmaline Strengthening

Landfill leachate is characterized by high ammonia nitrogen,low C/N,complex organic components,and easily changeable water quality with landfill time,making traditional biological treatment methods difficult to operate for a long period of time.Partial nitrification and annamox techonology(completely autotrophic nitrogen removal over nitrite,CANON)is a new type of autotrophic denitrification process that eliminates the need for additional carbon sources,saves energy,and reduces excess sludge and greenhouse gas emissions.However,anammox sludge is easy to lose,causing instability of the system.The biofilm carrier can effectively retain the sludge and enhance the impact resistance of the reactor.In this study,the tourmaline anaerobic ammonia oxidation biofilm adapted to the high ammonia nitrogen load was cultivated and the tourmaline strengthening CANON process system was successfully started in SBR.Landfill leachate was used as the treatment object and leachate treatment was completed without additional carbon source.Firstly,an anammox system with granular sludge and tourmaline biofilm fillers was established in UASB reactor.After 100 days of acclimation,the influent NH4+-N was increased from 30 mg/L to 420 mg/L,and the volumetric nitrogen load was increased from 0.08 kg·N/(m3·d)to 3.39 kg·N/(m3·d).The anaerobic ammonia oxidation activity in the reactor was good.The average removal of ?(NO2--N)/?(NH4+-N)and ?(NO2--N)/?(NH4+-N)was 1.14 and 0.22,it is close to the theoretical value.The organic nitrogen impact resistance of tourmaline filler was evaluated.Under the same matrix culture and film hanging time,the membrane speed and nitrogen removal efficiency of tourmaline carrier were better than that of ordinary sponge carrier.The average value of ?(NO2--N)/?(NH4+-N)at 30 d,45 d,and 70 d was 1.37 and 1.43,and the autotrophic level of tourmaline biofilm was higher,indicating that the activity of anammox could be promoted.The study investigated the resistance of the tourmaline biofilm to the impact of organic matter.Under the initial nitrite concentration of 125 mg/L and COD below 200 mg/L,two systems of anammox activity was not inhibited,but was promoted.However,when the concentration of COD was more than 300 mg/L,the reaction was significantly inhibited.Compared with carriers,the same quality of granular sludge showed bette r resistance to organic impact.The start-up of the tourmaline strengthening CANON reactor coexisting with shortcut nitrification floc and anammox tourmaline biofilm underwent partial nitrification stage and CANON stage.In the partial nitrification stage,p H monitoring of the "Ammonia Valley Point" was used to control aeration stoppage.After 65 days,the nitrous acid accumulation rate in the system was stable at more than 95%.Continuous integration of low-oxygen aeration and intermittent aeration was used to start CANON stage.After 192 days,the stirring reaction time stabilized at 18 hours.The effluent NH+4-N and COD concentrations were 9.13 mg/L and 476 mg/L.Total nitrogen removal load was 0.104 kg·N/(m3·d)and total nitrogen removal was 98%.Finally,in order to optimize the nitrogen removal efficiency of the process,the effects of dissolved oxygen concentration and different aeration and anoxic time allocation on the denitrification efficiency of the flocs and granules coexisted system were investigated.The results indicated that when the concentration of DO was less than 0.4 mg/L,the nitrogen removal rate increased with the increase of DO concentration.When DO concentration was 0.6 mg/L,the autotrophic process of the system was restrained.The system autotrophic process caused certain inhibition.The experimental aeration anoxic stirring time was 30 min/30 min,30 min/ 60 min and 10 min/30 min respectively.The results indicated that the greater the ratio of oxygen stirring time to total stirring time,the better nitrogen removal effect of the system.The nitrogen removal efficiency of the system was better if there were more time of aerobic alternating.Under the experimental conditions,the optimum DO concentration of the system is 0.40 mg/L,and the intermittent aeration mode is aeration 10 min/ hypoxia 30 min.