The effect of organic loading rate (OLR) on aerobic granulation was studied by adopting three column-shaped, sequential aerobic sludge blanket reactors (SASBR). The reactors had been fed with laboratory prepared, synthetic dextrose-nutrient broth substrate. Experimental results showed clearly that the formation, characteristics and stability of aerobic granules had a close relationship with the strength of OLR applied. Aerobic granules appeared firstly under the OLR of 4 kg COD×(m3·day)−1. The system stabilization was demonstrated by its little-changed amount and morphology of granules. The characteristics of the stabilized granules were: 5.4 mm in mean diameter, 1.29 in roundness, 118 mg O2·(mg VSS·hr)−1 in SPOUR. The respective biomass SVI was 50 mL·(g MLVSS)−1 and the averaged COD removal rate was 95%. Under the OLR of 8 kg COD·(m3·day)−1, granules appeared two days later than those for 4 kg COD·(m3·day)-1 and they always coexisted with flocs. The formed granule bed was not as compact as that under 4 kg COD·(m3·day)−1. There were no granules formed under the OLR of 1 kg COD·(m3·day)−1. Instead, flocs with rather loose structure dominated reactor mixed-liquor. The respective SVI's were 65 and 138 mL·(g MLVSS)−1 under OLR of 8 and 1 kg COD·(m3·day)−1. It was proposed that the growth and maintenance of aerobic granules follow the shear force balance theory. Under the OLR of 4 kg COD·(m3·day)−1, a balance was reached between the aeration shear force and organic loading rate. Under this favored condition aerobic granules formed quickly and, became stabilized with the experimental parameters remained unchanged.
The effect of organic loading rate on the aerobic granulation: the development of shear force theory
J.-H. Tay, S. Pan, S.T.L. Tay, V. Ivanov, Y. Liu; The effect of organic loading rate on the aerobic granulation: the development of shear force theory. Water Sci Technol 1 June 2003; 47 (11): 235–240. doi: https://doi.org/10.2166/wst.2003.0610
Download citation file:
Impact Factor 1.915
CiteScore 3.3 • Q2
First Decision in 30 days