[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.

[Process Optimization of Aerobic Granular Sludge Continuous-Flow System for the Treatment of Low COD/N Ratio Sewage].

The mature aerobic granular sludge (AGS) was inoculated in a continuous-flow joint constructor reactor to treat low chemical oxygen demand/nitrogen (COD/N) ratio sewage. The effects of aeration intensity and hydraulic retention time (HRT) on the denitrification and phosphorus removal efficiencies and the granular sludge stabilization were investigated. When the aeration intensity was 300 mL x min(-1) (superficial air upflow velocity of 1.2 cm x s(-1)) and the HRT was 7.5 h, the average removal efficiencies of COD, TN and TP were 76.34%, 51.23% and 53.70%, respectively. The mixed liquor suspended solids (MLSS) was only about 2 000 mg x L(-1), the sludge volume index ( SVI) was below 50 mL x g(-1), and the AGS exhibited complete forms and good settling performances. Additionally, the low COD/N ratios sewage could promote the production of extracellular polymeric substances (EPS) of AGS, and the PN proteins in EPS played a pivotal role in the maintenance of AGS stabilization.