[Cultivation of Aerobic Granular Sludge with Real Low Concentration Domestic Wastewater and Its Denitrification Performances Under the Continuous Flow]

The COD, ammonia and total nitrogen removal efficiency, as well as the physical properties of aerobic granular sludge (AGS) and its denitrification kinetics were studied in the continuous flow reactor. The experimental results showed that the AGS was successfully cultivated in the continuous flow system within 40 days. The nitrogen and carbon removal efficiencies were gradually improved with the improvement of sludge granulation. In the running stage of 41 - 60 days, the COD, ammonia and TN removal efficiency could reach 85. 54% , 95. 5% and 65. 56%, respectively. And the nitrate and nitrite nitrogen accumulation was not high in the reaction process. Mature AGS had more void structure and a large number of extracellular polymeric substances. It had significant advantages compared with the seed sludge in the aspects of moisture content, wet density, sedimentation rate, mechanical strength, and SVI values. The simultaneous nitrification and denitrification efficiency was 81. 69% , the nitrification rate and denitrification rate were 5.78 mg . (L.h) -1 and 4. 90 mg . (L.h) -1, respectively.