Cultivation and Characteristics Analysis of Nitrifying Granules in Sequencing Batch Reactor
LI Ling yun,PENG Yong zhen,WU Lei,WANG Shu ying and MA Yong
DOI:10.11835/j.issn.1674-4764.2010.03.021
Received September 10, 2009,Revised , Accepted , Available online July 01, 2015
Volume ,2010,Pages 119-123
- Abstract
A SBR inoculated with conventional activated sludge was employed to cultivate aerobic granular sludge.Under the selective pressure of settling time, the formation of nitrifying granules enriched with the ammonia oxidizing bacteria (AOB) was achieved by increasing the nitrogen loading rate (NLR).The nitrifying granule was shaped like a sphere or a ellipsoid with an equivalent diameter of approximate 1.1 mm, an average settling velocity of 1.9 cm·s-1and the sludge volume index of 18.2～31.4 mL·g-1.As the aerobic granular system was operated stably, the NLR reached a value of 0.045 5 kgNH4+ N· (kg MLSS·d)-1 with ammonia removal efficiency above 95% and nitrite accumulation ratio in the range of 80%～90%.The NLR was 4.55 times higher than that of the start up period.The enrichment of the nitrifying bacteria was quantified by FISH analysis which indicated that AOB was 14.9% of the total bacteria and nitrite oxidizing bacteria (NOB) was 0.89%.It is concluded that the associated inhibition of FA at the start of the reaction and FNA at the end of the reaction would be the key factors to start up and maintain the stable nitritation.