Study On The Treatment Of Vitamin Production Wastewater By Anaerobic Ammonium Oxidation

In this study,an upflow fixed bed reactor was used to inoculate sludge from a gravity concentration tank of a sewage treatment plant in Zhengzhou City.The sludge was greatly enriched by the filamentous filler,so that the anaerobic ammonia oxidation reactor was quickly started.Water quality was analyzed during the start-up process.Moreover,the denitrification capacity and the adaptability of anaerobic ammonium oxidizing bacteria to a pharmaceutical wastewater producing vitamin B2 were explored,which provided a reference for the engineering application of anaerobic ammonium oxidation process in vitamin production wastewater.The results show:?1?In the upflow fixed bed reactor,the filamentous filler was used to inoculate the sludge of the gravity concentration tank of the sewage plant,and the dissolved oxygen in the reactor was controlled to be 0.5 mg/L,the temperature was 37±1°C,the shading was controlled,and the NH₄⁺and NO₂^-loads were controlled respectively 0.050kg/?m³·d?and 0.066kg/?m³·d?,and anaerobic ammonium oxidation was achieved after72 days of continuous operation under this load.After the start-up stabilization,the removal rates of ammonia nitrogen and nitrite nitrogen reached 100%,and the removing velocity were 49.0 mg/?L·d?and 64.9 mg/?L·d?respectively;the effluent nitrate nitrogen was 3.27 times than influent;total nitrogen removal rate was 60.57%,total nitrogen removal rate was 76.05 mg/?L·d?.The pH value of the start-up process changed regularly,and the pH value can be used as an indicator parameter in the anaerobic oxidation initiation process.The ratio of the three nitrogen changes in the steady state was?NH₄⁺:?NO₂^-:?NO₃^-=1:1.33:0.33,which was close to the theoretical value of 1:1.32:0.26.After start-up,anaerobic ammonium oxidation played a major role in the system.After the start-up,the surface sludge on the outermost layer of the filler was red,and the inner sludge adjacent to the filler was tawny,and the distribution of anaerobic ammonium oxidizing bacteria was not uniform,and the filler near the water inlet was dark red.Anaerobic ammonium oxidizing bacteria was assembled obviously.?2?The actual wastewater treatment was carried out by using the anaerobic ammonia oxidation reactor that has been successfully started,under the same environmental conditions.The test was divided into four phases:buffer phase,phase I,phase II,and phase III.In the buffer phase,the degradable glucose was added to adapt the sludge to the environment in which the organic matter exists.In phase I,the diluted actual wastewater,COD,NH₄⁺,NO₂^-,and TN removal rates are 74.03%,95.55%,90.05%,and 70.6%,respectively.In phase II,the load was increased.At this stage,the anaerobic ammonium oxidation reactor reached the maximum pollutant load that it could withstand.And the removal rates of COD,NH₄⁺,NO₂^-,and TN were 74.12%,95.01%,88.98%,and 75.66%,respectively.The removing velocity of TN reached a maximum of 0.25kg/?m³·d?,and the nitrogen removal performance and bacterial activity at this stage were improved compared with the previous stage.In phase III,with the load further improved,the activity of the Anammox bacteria was deteriorated,the denitrification performance was drastically decreased,and the denitrification effect of the Anammox bacteria was almost eliminated.The ratios of NO₂^-/NH₄⁺in the four stages of influent were:1.32,1.32,1.11,1.35,and the ratios of?NO₂^-/?NH₄⁺were:1.27,1.24,1.04,0.04.In the first three stages,the activity of bacteria and denitrification performance were better.The ratio of?NO₂^-/?NH₄⁺also fluctuated with the change of NO₂^-/NH₄⁺ratio of influent water,and the change range was slight.In phase III,the anaerobic ammonium oxidizing bacteria activity and the denitrification performance of the reactor were significantly deteriorated.After the test,the sludge attached to the outermost layer of the filler showed a deep mulberry color,and the inner sludge showed a dark brown color.Compared with the sludge after the start-up test,except the change in color,anaerobic ammonium oxidizing bacteria not only appeared on some of the filler adjacent to the water inlet,but were more evenly distributed on the surface of the filler.After the treatment test on actual wastewater,the sludge MLSS decreased to 6984 mg/L,and MLVSS/MLVSS was 0.53.The sludge concentration decreased significantly,and MLSS/VSS showed that the sludge activity was weakened after process of start-up and actual wastewater treatment.