ABSTRACT
In the SBR reactor, the mixed traditional activated sludge and aerobic granules were used as seed sludge to cultivate aerobic granular sludge. The whole research can be divided into two phases. In the first stage, different proportions of aerobic granules (ten, fifteen and twenty percent) were added to three SBR reactors, respectively. In the second stage, aerobic granules of different sizes (unscreened, smaller than or equal to 1 mm in diameter, larger than 1 mm in diameter) were added to three SBR reactors with the proportion of twenty percent, respectively. During the cultivation, the morphological change of the sludge, variation of particle size, maturity time and removal rate of pollutants were studied. The mechanism of fast cultivation was also discussed. The results showed that the reactor with twenty percent aerobic granules had the shortest maturity time of 24 days in the first stage and the reactor with unscreened aerobic granules had the shortest maturity time of 30 days in the second stage. All the cultivated aerobic granules had a good settling property and detergency performance, with the SVI distinctly below 40 mL x g(-1) and the COD removal rate staying above 90%. The formation of aerobic granules could be divided into two stages: the accelerated disintegration stage and the disintegration and rapid forming stage.
