The Study Of Embedding Immobilization Aerobic Denitrifying Bacteria And New Bioreactor

As a new type of wastewater denitrification technology,aerobic denitrification technology is able to reach the simultaneous nitrification and denitrification,which simplify the conventional denitrification process,and is brought into focus.But in the practical application,the aerobic denitrifier has a limitation of erosion and is hard to become a dominant fungi strains.In this paper,we immobilized the aerobic denitrifying bacteria into the embedding immobilized microorganism bead(IMB),inspected its aerobic denitrification performance and explored the suitable process parameters of IMB aerobic denitrification reaction.In addition,a new type of coupled multistage gas-lift internal circulating three-phase fluidized bed reactor was designed for IMB aerobic denitrification reaction,and the feasibility of the reactor was investigated.Two strains with high efficiency heterotrophic nitrification-aerobic denitrification were successfully isolated from the activated sludge samples of Tianjin Dagang biological pool,which named as AD-2 and AD-5 respectively.Accroding to the analysis and identification of 16 SrDNA sequence,the strain AD-2 is pseudomonas schlieren,and the strain AD-5 is pseudomonas MLB.Both AD-2 and AD-5 had an excellent ability of aerobic denitrification and heterotrophic nitrification.Their aerobic biodegradation rate of nitrate nitrogen were above 95%,and the accumulation of nitrite-nitrogen were 0.013 mg/L and 0.0 mg/L respectively.Both AD-2 and AD-5 had more than 50% degradation rate of ammonia nitrogen,the accumulation of nitrite-nitrogen were close to zero,and the accumulation of nitrate nitrogen were relatively low.IMB also characterized good denitrification performance against nitrate nitrogen.But under the same aerobic denitrifying bacteria additive quantity,the aerobic denitrification performance of IMB was significantly weaker than bacteria in suspended state,and there were also part of the nitrite-nitrogen accumulation.In the aerobic denitrification reaction of IMB,the suitable technology conditions were: C/N for 9,sodium succinate and sucrose as carbon source,the initial nitrate nitrogen concentration of 300 mg/L,and solid-liquid ratio as 0.1.In this paper,a new coupled multistage gas-lift internal circulating three-phase fluidized bed reactor was designed,which combines the advantages of biologicalfluidized bed reactor and bioreactor.The feasibility of stable operation of the new reactor is proved by the preliminary operation test.