沼液二级生化出水铁硫协同同步硝化-自养反硝化深度脱氮OACSTPCD

Aiming at the problems of high concentration of nitrate nitrogen(NO3--N)and ammonia nitrogen in the secondary biochemical effluent of biogas slurry,the influencing factors of iron-sulfur synergistic enhanced simultaneous nitrification-autotrophic denitrification were studied.The results showed that under the conditions of no external carbon source,iron-sulfur synergy could enhance the simultaneous nitrification-denitrification and effectively improve the removal rate of TN,NO3--N and ammonia nitrogen.Then,the results showed that the optimal S/N was 2.0,and the removal rates of TN,NO3--N and ammonia nitrogen under this condition were 51.25％,83.63％and 67.33％,respectively.Further,the optimal S/N conditions were selected to study the nitrogen removal kinetics of the process,and the results showed that the TN removal pattern conformed to the first-order reaction kinetics within 0～15 h,and its reaction rate constant(0.051 0 h-1)was higher than that of the control with no addition of iron scraps and sodium thiosulfate(0.035 5 h-1).The microbial community evolution under the optimal S/N condition revealed that the addition of ironscraps and sodium thiosulfate increased the richness and decreased the diversity of microbial communities.The addition of iron scraps and sodium thiosulfate significantly increased the abundance of autotrophic denitrifying bacteria(Thiobacillus,Ferribacterium)and heterotrophic denitrifying bacteria(Defluviicoccus,Candidatus_Competibacter,Thauera).