Experimental Study On Start Up And Influencing Factors Of Anammox Biofilter

Increasingly along with the social progress,more and more production of natural wild for human life behavior of nitrogen intermediate in the nature of a large number of accumulation,make the nitrogen cycle in the nature out of balance,causing serious pollution to the environment,in recent years,the widely advocated the concept of sustainable development of reasonable utilization of resources at home and abroad,compared the traditional biological denitrification technology,Anaerobic ammonia oxidation（ANAMMOX）,a new biological nitrogen removal technology,has more advantages.If this process can be applied in urban sewage treatment,the nitrogen removal efficiency can be significantly improved,which is of great significance for the protection of resources and environment in China.In this paper,a biological filter reactor was used for the test.The process was divided into two stages.The first stage was the start-up test of the anaerobic ammonium oxidation biological filter,and two groups of parallel tests were carried out to start the filter.In one group of tests,denitrifying sludge in anoxic section was used as inoculation sludge,and in the other group,UASB granular sludge was used as inoculation sludge.The second stage is to investigate the influence of environmental factors on the denitrification performance of the biological filter after the stable operation of the filter.The anaerobic phase denitrifying activated sludge successfully started the reactor in only 100 days,10 days before the inoculation with UASB granular sludge.The results indicate that denitrifying activated sludge in the anoxic section is more suitable for enriching and improving the activity of anaerobic ammonia oxidation bacteria（AOB）.After stable operation of the two biofilter reactors,the NLR and NRR are 0.112kg TN·m^-3·d^-1and 0.079kg TN·m^-3·d^-1,respectively.The total nitrogen removal rate reached 74%and 72.2%,respectively.The total nitrogen removal rate is affected by the formation of nitrate nitrogen in the reactor.By shortening the hydraulic retention time and increasing the volumetric load,it is an effective method to accelerate the enrichment of ANAMMOX bacteria in ANAMMOX biological filter.With the increasing concentration of nitrite nitrogen and ammonia nitrogen,the reaction rate in the anaerobic ammonium oxidation biological filter can be divided into two processes.In the first stage,the reaction rate of anaerobic ammonium oxidation increases with the increasing concentration of nitrite nitrogen and ammonia nitrogen.When the concentration of nitrite nitrogen is 90mg/L and the concentration of ammonia nitrogen is 68mg/L,The maximum reaction rate of ANAMMOX was4.37mmol·L^-1·d^-1,and the total nitrogen removal rate was 81%.In the second stage,the anaerobic ammonium oxidation bacteria（AOB）showed obvious inhibition after the concentration of nitrite and ammonia nitrogen was 110mg/L and 85mg/L,respectively.The total nitrogen removal rate decreased continuously.When the nitrite nitrogen concentration was greater than 230mg/L,the reaction rate of ANAMMOX was less than 1mmol·L^-1·d^-1,and the total nitrogen removal rate was less than 10%.pH has a direct impact on the process of anaerobic ammonium oxidation（ANAMMOX）.When pH=7.75,the reaction rate is the fastest.When pH is less than6.5,the activity of anaerobic ammonium oxidation bacteria（AOB）is basically lost,seriously affecting the ANAMMOX reaction.When the temperature is between 30℃and 35℃,the volumetric removal load of total nitrogen is high,and the anaerobic ammonium oxidation biological filter has the best denitrification performance.The maximum TN volumetric removal load can reach 0.126/kg·m^-3·d^-1.However,with the decrease of temperature,the volumetric removal load of total nitrogen decreases,from 20℃to 15℃.The denitrification performance of ANAMMOX biological filter began to decline greatly,and the total nitrogen volume removal load decreased to 0.024/kg·m^-3·d^-1.When the ratio of carbon to ammonia-nitrogen is 3～4.5,the anaerobic ammonia oxidation biological filter has the best nitrogen removal performance,with the highest TN removal rate of 91.5%and the average TN removal rate of 88.3%.When the ratio of carbon to ammonia nitrogen is 6.0,the TN removal rate drops to 50%,and when the ratio of carbon to ammonia nitrogen is 7.0,the TN removal rate drops to 15.1%.