| For traditional nitrification and denitrification denitrification, Denitrification process cannot effectively when C/N<3 if no plus organic carbon sources,So, The traditional biological denitrification cannot satisfy the requirements of low carbon and high ammonia nitrogen wastewater treatment, Looking for a suitable for low carbon and high ammonia nitrogen wastewater treatment process is imperative. Autotrophic nitrogen removal process could realize the conversion of ammonium to denitrogen gas by autotrophic bacteria, and it particularly suitable to treat high Ammonium and low C/N ratio wastewaters. At present, Most researches of autotrophic nitrogen removal process on condition of inorganicwastewater,but it is not exist in practical wastewater,It need to research the adaptability and stability of autotrophic nitrogen removal process on condition of organic wastes. This study adopts autotrophic nitrogen removal process treatment low carbon and high ammonia nitrogen wastewater, On the basis of one-stage completely autotrophic nitrogen removal process which is established by our group early, With low C/N wastewater as matrix.This paper studied DO&C/N impact on the performance of system denitrification during the start-up process system;it also studied microbial activity and microbial community structure of the different sludge forms in the system during stable operation stage. Main conclusions are as follows:Using two biofilm SBR reactor (A and B) to startup autotrophic nitrogen systems for low C/N ratio and high ammonia nitrogen wastewater,Inflow water quality and exercise macro-control condition of the two reactor are conformity.Domestication the sludge by gradually improve the concentration of COD and NH4+-N in the process of start, Eventually COD and NH4+-N concentration of inflow water are 240~255mg/L and 245~295mg/L, start-up process go through 91d. control condition of initial stage(1~24d) are pH:7.8～8.5,water temperature:30±2℃,DO:2.0～2.5(aeration)/0.2～0.4(not aeration), TN removing rate is 60% in system,and NO3--N concentration of effluent water is high. At 25d, Reduce the concentration of DO to 1.4～1.7(aeration)/0.2～0.4(not aeration), Other conditions remain unchanged, nitrogen removal in system is greatly improved and NO3--N concentration is reduced after a period of time, TN removal rate reached more than 90% in both of A and B system at the startup end. With the increase of the inlet C/N ,Theoretical calculation that autotrophic nitrogen removal pathway by 90% decline to 60% and traditional nitrification and denitrification pathway by 10% to 40%, autotrophic nitrogen removal pathway is still dominant.Taking the suspended sludge and biofilm in autotrophic nitrogen removal system as the research objects, Results showed that nitrosification activity, nitrification activity, ANAMMOX activity and denitrification activity of suspended sludge were 0.07gN/g VSS·d,.043gN/gVSS·d,0.17gN/gVSS·d and 0.015gN/gVSS·d, nitrosification activity, nitrification activity, ANAMMOX activity and denitrification activity of biofilm were0.112gN/ gVSS·d,077g N/gVSS·d, 0.15gN/g VSS·d and 0.19gN/gVSS·d, Microbial activity of biofilm is higher than suspended sludge, especially ANAMMOX activity and denitrification activity, which for the suspended sludge were 9 times and 13 times. which indicate that biofilm is more beneficial for the formation of aerobic-anaerobic micro-environment to make nitrification and ANAMMOX reaction perform well, and biofilm played dominant parts in autotrophic nitrogen removal system. Both of the suspended sludge and biofilm showing the denitrification activity and ANAMMOX activity,which proof that traditional nitrification and denitrification pathway and autotrophic nitrogen removal pathway existence in the system at the same time.Using PCR-DGGE to study total microbial community structure and functional bacteria community structure (AOB and ANAMMOX) in A,B and C system, Experimental results that AOB community structure of suspended sludge and biofilm are basically the same,but The number and variety of the total microbial community structure and ANAMMOX community structure in biofilm are more than in suspended sludge, Compared with microbial community structure of the system which With inorganic wastewater as matrix, After joining the organic carbon source, Besides the community structure of AOB not changed,the total microbial community is more complex, The variety of ANAMMOX have great change.The research results of this topic could provide reference and theoretical basis for autotrophic nitrogen removal process applied to practical engineering.
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