Study On External Carbon Source Enhanced Deep Denitrification By Anaerobic Ammonia Oxidation

The ANAMMOX denitrification has the advantages of low sludge yield and no need of additional carbon source,which can improve the efficiency of sewage denitrification.At present,the removal rate of TN in laboratory stage reaches 70%⁸0%and can not completely denitrify.This experiment studied the start-up of anaerobic ammonia oxidation reactor,the influencing factors of isoaerobic denitrification,high-throughput sequencing technology to analyze microbial flora structure changes,using sodium acetate,sodium propionate,glucose,sucrose,lactose,starch,valeric acid and hexanoic acid as eight organic carbon sources to carry out batch experiments,and selected three better carbon sources to join UASB reactor for continuous experiments to study anaerobic.The effects of different C/N ratios and carbon sources entering the reactor on anaerobic ammonia oxidation and denitrification depth denitrification were studied,so as to provide scientific basis for practical application.The main conclusions are as follows:the start-up of anaerobic ammonia oxidation reactor needs three stages,namely,sludge adaptation stage,sludge growth stage and sludge maturity stage.The denitrification performance of sludge is better than anaerobic ammonia oxidation,the removal rate of TN is only 8.16%,while the removal rate of TN is 36.97%during the sludge growth period,and AAOB activity is enhanced,which gradually adapts to the water quality environment.The concentration of NH₄⁺-N and NO₂^--N in sludge maturation period were lower than 15 mg/L,and the removal rate of TN was 80.90%.AAOB became the dominant bacteria.By high throughput sequencing,Candidatus Brocadia fulgida and Candidtus Brocadia caroliniensis were the main anaerobic ammonia oxidizing bacteria in the system.The research on the effect of denitrification shows that the larger the sludge dosage is,the faster the nitrification of NO₃^--N is,and the ability of denitrification depends only on the amount of bacteria;the larger the sludge size is,the stronger the resistance to environmental and substrate concentration shocks is,but the smaller the particle size is,the less adaptable it is to environmental conditions and substrate concentration shocks,but under suitable conditions,the activity is stronger.Relatively higher.Sodium propionate,sodium acetate and glucose with better denitrification performance were selected for deep denitrification experiments.The results showed that sodium acetate was more conducive to the coupling of anaerobic ammonia oxidation and denitrification.AAOB was enhanced at 8days and the average TN removal rate was 85.11%at the end of the reaction.The C/N ratio of seed played a positive role in deep denitrification.The best removal efficiency was 87.75%when the C/N ratio of sodium acetate was 3.6:1.The denitrification performance is 3.6:1>1.8:1>2.7:1 in turn;the deep denitrification effect of sodium acetate C/N is the best when it is put into the reactor from the reactor,and the removal rate of TN reaches 90.23%.The reason is that both anaerobic ammonia oxidation and denitrification react simultaneously in the middle of the reactor,and the NO₂^--N produced by denitrification can rapidly react with NH₄⁺-N to produce N₂ to provide an electronic acceptor for anaerobic ammonia oxidation.