FORMATION AND CHARACTERISTICS OF AEROBIC GRANULAR SLUDGE CULTIVATED UNDER LOW TEMPERATURE IN THE SEQUENCING BATCH REACTOR

Both biological activities and microorganism species of the granular sludge could be influenced by low temperature. To investigate the possibility of applying aerobic granular sludge technology in winter, a sequencing batch reactor (SBR) was developed to study the formation and characteristics of the aerobic granular sludge cultivated under low temperature. Results indicated that in the SBR inoculated with flocculent sludge, aerobic granules could appear within 3 days under water temperature of 6.0-8.0 degrees C. Moreover, the flocculent sludge could completely convert into granular sludge within 15 days, which was much more efficient than previous results. Furthermore, the granular sludge was characterized with average diameter of 6.0 mm, settling velocity of 90 m h(-1), water content of about 92%, adsorption capacity of 100 mg Pb(2+)mg(-1) MLSS-1 and dominated by filamentous bacteria all along, as well as efficient biochemistry activities of simultaneously removing COD, NH4+-N, TN and TP in a solely aerobic condition.