| The anaerobic ammonium oxidation(Anammox) process has advantages of carbon and energy savings as well as low sludge production and is one of the most important progresses in wastewater biological nitrogen removal, especially wastewater with high ammonia content and low organic matter content. N2H4 and NO are the important intermediates of Anammox. The appropriate addition of N2H4 weakens the inhibitory effect of NO2- on anaerobic ammonium oxidation bacteria(An AOB) activity. Therefore, further studyfor the effect of trace N2H4 addtion on Anammox, the stoichiometry and kinetics of anaerobic ammonium oxidation(Anammox) with trace hydrazine addition, NO removal by Fe(II)EDTA absorption-Anammox reduction and the realization of anoxic ferric ammonium oxidation(Feammox) base on Anammox were investigated in this thesis. The achievements would provide important theoretical basis for the engineering application of Anammox. The results were given as follows:① A sequencing batch reactor(SBR) performing Anammox could run stably during long-term addition of micro-amount of N2H4. The nitrogen removal rate and efficiency of the SBR with micro-amount N2H4 addition were higher than the SBR without N2H4 addition. The molar ratio of NO3- production to NH4+ removal(MRNN) decreased to 0.12, significantly lower than the expected stoichiometry of Anammox. The NO emission decreased by more than 15%. The addition of micro-amount N2H4 could weaken the inhibition of NO2- to the activity of anaerobic ammonium oxidation bacteria(An AOB).There was a significant loss of intermediates(N2H4 and NO) in Anammox.The effective concentration of N2H4 addition in short time was approximately 4.86mg/L.② The stoichiometry was established based on the electron balance of Anammox process with trace N2H4 addition. The stoichiometric coefficients were determined by the proton consumption and the changes in substrates and products. It was found that trace N2H4 addition can increase the yield of Anammox bacteria(An AOB) and reduce NO3- yield, which enhances the Anammox. Kinetic model of Anammox with trace N2H4 addition was developed, and the parameters of the anaerobic degradation model of N2H4 were obtained for the first time. The maximum specific substrate utilization rate, half-saturation constant and inhibition constant of N2H4 were 25.09 mg N/g VSS/d, 10.42 mg N/L and 1393.88 mg N/L, respectively.③The effect and the affecting factors of NO removal by Fe(II)EDTA absorption-Anammox reduction was investigated by batch tests. The removal efficiency and removal rate of NO was enhanced by the Fe(II)EDTA addition. The removal efficiency and removal rate of NO improved from 2.9%~11.1%, 0.23~0.56 before addition to 74.5%~85.4%, 1.62~15.48μmol NO/(g VSS?h) after addition, respectively.The NO removal efficiency and rate first increased then decreased with the increase of temperature from 25℃ to 45℃, and the suitable temperature was range from 30-35℃. The NO removal efficiency and rate appeared the same variations characteristics with p H increased from 6.5 to 8.0, and the appropriate p H was 7.0-7.5. The results indicated that Fe(II)EDTA concentration had significant effect on NO removal efficiency, and is the key factor for increasing the NO removal efficiency. NO concentration and gas velocity had significant effects on NO removal rate.The maximum specific substrate utilization rate and half-saturation constant of NO were 0.09 mmol N/(g VSS?h) and 1.338 m M, respectively.④ MLVSS of the Anammox SBR decreased gradually during the 35 d operation was only 52.95% of the initial period. The NO removal efficiency and removal rate also decreased. The diversity and abundance of the bacteria decreased. Sequences related to Planctomycetes decreased 91.3%. The structure and the population quantity of bacteria stability cannot keep stable under 500 ppm NO. These results indicated that it was not possible to maintain the long-term stability removal of NO only by Fe(II)EDTA absorption-Anammox reduction.⑤ The realization of Feammox base on Anammox was investigated. Enrichment cultures of Anammox sludge can mediate anaerobically nitrate-dependent ferrous iron oxidation and Feammox. Fe(III)NTA can oxidize NH4+ while Fe(III)EDTA cannot. It was microorganism mediate Feammox rather than chemicalreaction and metabolites of microorganism. Microbes mediating Feammox could exist in Anammox sludge. 200mg/L chloramphenicol or 10 m M methanol can partly inhibit Feammox, and the coexistence of them could completely inhibit Feammox. The TN removal rate of Anammox can be enhanced by 0.09~1.07 m M Fe2+, Fe3+ or Fe(III)NTA addition. The maximum TN removal rates, which were 1.46, 1.40 and 1.39 times that of the rates with no Fe addition, were observed in the 0.09 m M Fe2+, Fe3+ or Fe(III)NTA addition test, respectively.⑥ The maximum Feammox rate, which was 75.19 mg N/(g VSS?d), was observed in the 0.09 m M Fe(III)NTA addition test. The Feammox rate decreased above a Fe(III)NTA concentration of 0.09 m M. The Feammox rate and TN removal rate of the SBR, which were 55.54% and 142.23% higher than the beginning, increased to 117.12 and 142.89 mg N/(g VSS?d) after 60 d operation, respectively.The accumulation of NO2-decreased gradually after day 28. Some phyla of bacteria were co-exist in Anammox sludge which was aim to achieve Feammox. Most of the An AOB was Kuenenia. The bacterium develops a community that features simplification. The functionalmicroorganisms need to be quantitative in the follow-up cultivation. |
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