Regularity For Change Of Enzyme In Wastewater Treatment With A/O Process

A laboratory-scale reactor for the A/O process was fed with simulating municipal living wastewater.In the course of sludge acclimation,stablization,deteriorating and debugging process,the urease,catalase,dehydrogenase,acid phosphatase activities and their correlations with the process parameters were studied as well as the microorganisms.In the period of sludge acclimation it was found that the four enzymes activties achieve the pinnacle accompanying the success of sludge acclimation while the CODCr removal rate reach the high level,corresponding appropriate biological phase of removing CODCr basically.During the stable sludge operation,urease activity was positively correlated with the CODCr removal as well as the TN removal.CODCr removal rate is positively correlated with dehydrogenase activity as well as catalase,while it was confirmed that the enzyme activty was the highest when SV30=(2 5±3)%through studying the relationship between urease,catalase and SV30.It is considered that DO in 3-4 mg/L is more suitable for inter-system operation.When the influent CODCr concentration was at 480 mg/L,the water quality parameters and enzyme activities reached a maximum value;urease,catalase,dehydrogenase and acid phosphatase activity in aerobic zone reached 15.12 U/g,368.00 U/g,28.28 U/g,46.79 U/g separately.The urease,catalase,dehydrogenase,acid phosphatase activities of aerobic zone reached 15.70 U/g,370.12 U/g,29.22 U/g,47.08 U/g when the inlet flow rate was controled as 11 mL/min(HRT was 4.8,8 h in anaerobic zone and aerobic zone separately).By mesuring sludge activity in the process of sludge deterioration,it was showed that sludge index(SVI)was changed by rising which was beyond the normal finally.In this process,dehydrogenase and catalase showed significant positive correlation with CODCr and ammonia nitrogen removal rate respectively.In another hand,catalase and dehydrogenase could also reflect the trend of sludge disintegration.moreover,urease activity was associated with the TN removal and acid phosphatase activity was associated with TP removal.The connections of enyzme actities,quality parameter and biological phase were disgussed after the reactor was re-commissioned,it was indicated that the propeties in this system was simliar with domestication process,verifying the sludge can be characterized by enzyme activity of the sludge.