Formation and Characteristics of Aerobic Granular Sludge for Simultaneous Phosphorus and Nitrogen Removal in a SBR
With inoculum sludge from a conventional activated sludge wastewater treatment plant, formation of aerobic granular sludge for simultaneous phosphorus and nitrogen removal was realized in a sequencing batch reactor by the selective pressure as a driving force. Selective pressure created by means of decreasing sedimentation time and increasing substrate loading enhanced the formation of aerobic granular sludge, which followed four consecutive stages: acclimation, granulation, growth and maturation. Under the condition that the substrate loading were increased to 500mg COD/(L•d) and 48mg NH4 +-N/(L•d), the granules were the dominant sludge forms with most of diameter about 0.5–2.0 mm, a minimal settling velocity of 0.55 cm/s and a MLSS of 6800 mg/L after 120 days operation. The granules were composed of filamentous species with varying degrees of rod- and coccal-type bacteria. Microscopic examination revealed that granules microecosystem was more stable and should be less vulnerable to the changes of mixed liquor condition.
Hexing Li, Qunjie Xu and Daquan Zhang
G. J. Yang et al., "Formation and Characteristics of Aerobic Granular Sludge for Simultaneous Phosphorus and Nitrogen Removal in a SBR", Advanced Materials Research, Vols. 356-360, pp. 1630-1636, 2012