Influence of Seed Sludge on Granulation in SBR for Biological Phosphorous Removal

Using flocculent sludge with/without filamentous bacteria as seed sludge,granular sludge with phosphorus removal capability was cultivated in SBR.The results show that the sludge granulation starts on the 10th day for sludge with filamentous bacteria and on the 43rd day for sludge without filamentous bacteria,and is complete on the 20th and 82nd days,respectively.For both kinds of flocculent sludge,the diameter of the formed granular sludge is 0.5 to 1 mm and SVI is 30 mL/g,but the differences in the sludge morphology and activity are significant.In addition,the concentrations of water and metal elements in the granular sludge obviously decrease during sludge granulation.