Regularity for Change of Urease and Catalase in Wastewater Treatment with Activated Sludge Process

A laboratory-scale reactor for the activated sludge process was fed with simulating municipal living wastewater. In the course of operation, the urease and catalase activities and their correlations with the process parameters and microorganisms were studied. The results showed that during the sludge acclimation process, the activities of two enzymes were closely related to the microorganisms and SV
₃₀
value. Enzymatic activities reached the maximum when SV
₃₀
value was at (25±3)%. As the SV
₃₀
value continued to increase, there were significant negative correlations between the SV
₃₀
value and enzyme activities with r values of -0.902 and -0.911 respectively. The sludge enzymatic activities could maintain a high standard and stability within 14 d. Besides, during the stable operation period, the CODCr removal rates were positively correlated to activities of urease and catalase with r values of 0.756 and 0.793 respectively. Those suggested that the operational status of the activated sludge system and the sludge activity could be well characterized by urease and catalase activities.