ACTIVATED SLUDGE ACTIVITY IN THE TREATMENT OF ANAEROBIC SLUDGE DIGESTER SUPERNATANT

摘要

The objective of the study was to examine the effect of the food/microorganisms (F/M) ratio on the respirometry of activated sludge treating anaerobic sludge digester supernatant at low oxygen concentration (DO) of 0.7 mg O_2/dm~3. Exogenous respiration rate (SOUR_1), endogenous respiration rate (SOUR_3) and the rate of oxygen uptake for nitrification (SOUR_2) were evaluated. Taking into consideration that BOD_5/COD in anaerobic digester supernatant was 0.53, it may be supposed that weak activity of heterotrophic bacteria (low SOUR_1) resulted from low DO concentration in the reactor, and not from limited accessibility of biodegradable substrate. At the F/M ratio of 0.05-0.26 g COD/(g TSS·d), SOUR_2 was from 2.1-fold to 20.6-fold higher than SOUR_1 Further increase in the F/M ratio induced a decline in SOUR_2 but the efficiency of nitrification enhanced.