The Effect Of COD/NH 4 + -N And Temperature On Anaerobic Ammonium Oxidation And Denitrification Coupled With Nitrogen And Carbon Removal

An anaerobic sequencing batch reactor?ASBR? was operated to investigate the effect of COD/NH₄⁺-N on nitrogen removal via anaerobic ammonium oxidation and denitrification by gradually increasing the concentration of ammonia in influent. The results showed that when COD and NO2--N was 300 and 145 mg/L, respectively. COD/NH₄⁺-N was the main factor affecting the nitrogen removal contribution made by anammox process. However, the ratio of COD/NH₄⁺-N had no significant effect on nitrite remove efficiency. When COD/NH₄⁺-N was 1³.25, the contribution rates made by anammox process to nitrogen removal were kept steady on 73.03%. When COD/NH₄⁺-N was 3.75, the contribution made by anammox process to nitrogen removal began to decline from 71.76% to 55%. When COD/NH₄⁺-N was 4.25⁵.25, anammox and denitrification played equal role in nitrogen removal. When COD/NH₄⁺-N was 6.5¹2.5, the contribution rates made by denitrification process were kept being increased from 51.69% to 79.62% with the rising of COD/NH₄⁺-N.There are three forms of granular sludge existing in ANAMMOX and denitrifcation coupled reactor: the ANAMMOX granular sludge, the deniftrifying granular sludge and the granular sludge containing anammox bacteria that was wrapped up with denitrifying bacteria. Granulation of activated sludge became stronger and stronger with the reactor operating, and the granular diameter was mainly between 0.6¹.5 mm. MLSS increased from 11.2 g/L to 19.4 g/L, and SV% rised from 19.5% to 24.1%, and SVI fell from 17.4mL/g to 12.4mL/g. The settling performance of sludge was good.An anaerobic sequencing batch reactor?ASBR? was operated to investigate the short effects of temperature on nitrogen removal via anaerobic ammonium oxidation and denitrification process by regulating water bath temperature. The results showed that the activation energy of the coupled reaction contained anammox and denitrification process was lower than the single reactor only contained anammox process. The coupled reaction could balance the negative effects of low temperature. Decrease in temperature had more severe effects on anammox process than denitrification process. The relationship between temperature and the maximum specific nitrogen removal rate could accord with Arrhenius equation. The activation energy of coupled reaction was 49.56 kJ/mol which was lower than 66.18 kJ/mol calculated by anammox reaction at 25³5? and anammox was the dominated reaction in the reactor whose contribution rates to nitrogen removal were 61.29%. The activation energy of coupled reaction was 74.91 kJ/mol which was lower than 106.40 kJ/mol calculated by anammox reaction at 9²5?. The contribution rates made by denitrification to nitrogen removal were increased with the decreasing of temperature. Denitrification became the dominated reaction when the temperature dropped to 9?, and its contribution rate to nitrogen removal was 75.10%. The results also showed that the volume of nitrogen removal rate?NRR? would be influenced by temperature when temperature was lower than 25?.