[Study on the biological activity of activated sludge using a rapid biological activity tester]

Based on a Rapid Biological Activity Tester (RBAT), a study was taken on the sludge activity which is one of the most important parameters in the operation of aerated biological treating unit in WWTP to measure the effect of the external environmental conditions on the sludge activity, such as acidity and alkalinity, temperature, toxicity, etc. It is observed that the variety of the activity parameters is limited in 20% for a long time. While pH is deviated from the normal value, the biological activity drops to some degree, and furthermore, the ability of the microorganism to endure the acerbic environment is much higher than that to endure the alkaline environment. Temperature increase can result in the enhancement of the biological activity, and if the temperature is higher than 42.5 degrees C, the biological activity is greatly inhibite, but the endogenous respiring rate is less influenced by high temperature. Toxicity can greatly inhibit the biological activity of the activated sludge, and the inhibition is probably selective. Finally, the biological activity of the activated sludge from a real wastewater treatment plant was tested, and the standard deviation of the result is less than 20%. The results indicate that the RBAT is a promising method to measure biological activity, and the characteristics of activated sludge can be well expressed.