Colonizing Methods And Ammonia Removal Performance Of Immobilized Nitrifying Sludge

With the increasingly pressing water pollution problems,people’s requirements on the effluent water quality gradually increased.In this article,with the combination of the biological immobilization technology and functional microbes,the problem of low growth rates of autotrophic nitrifying bacteria and biomass loss caused by the external environment was solved.The effects of immobilization methods and parameters on the nitrogen removal effic iency of nitrifying bacteria were studied.Colonization efficiency and microbial community structure of the SBR reactor were studied using bioaugmentation technology of immobilized nitrifying bacteria to treat high ammonia nitrogen wastewater.This study is of great significance to further bioaugmentation technology of immobilized nitrifying bacteria and provide theoretical support for future process application.By optimizing the immobilization parameters for different carriers,the optimum reaction conditions of SA(sodium alginate)carrier were as follows: the concentration of SA was 5%,the concentration of CaC l2 was 1%,the crosslinking time was 24 hours,and the amount of nitrifying sludge was 1.5 g;the optimum reaction condit ions of PVA(polyvinyl alcohol)carrier were as follows: the concentration of PVA was 13%,the crosslinking time was 22 hours,and the amount of nitrifying sludge was 1 g;the optimum reaction condit ions of SA carrier were as follows: the optimum reaction conditions of chitosan carrier were chitosan concentration of 2.5%,NaOH concentration of 1.25 mol/L,the amount of nitrifying sludge was 1.5 g;the best reaction conditions for mycelia l pellet carrier immobilization was immobilizing for 48 hours,and the amount of nitrifying sludge was 1 g.It can be concluded that according to the comparison of the morphology and performance of the carriers before and after immobilization,SA and PVA are ideal immobilized carrier materials.The removal rate of ammonia nitrogen in SBR reactor was increased by SA and PVA immobilized nitrifying bacteria.After immobilized with SA carrier,removal rate of ammonia nitrogen reached 87.7%,which was increased by 4.2%,comparing with the direct inoculation group.As with PVA carrier,the removal rate of ammonia nitrogen was 100%,which was increased by 16.5%,comparing with the direct inoculation group.The microbial community structure of the sludge sample s and the carrier samples in the SBR reactor were analyzed using Illumina high throughput sequencing.The relative abundance of nitrifying bacteria biomass increased after addition of immobilized activated sludge in the reaction system.The content of N itrosomonas in the community structure of PVA was larger,indicating that the bio-immobilization can help the nitr ifying bacteria to become dominant flora,which was beneficial to nitrification,and solved the problem of biomass loss successfully.The existence of denitrifying bacteria in SA and PVA was also proved.After the process of biological immobilization,the system was dominated by nitrifying bacteria,which enhanced the nitrogen removal efficiency.