| Abstract |
| This study investigated the sludge characteristics of activated sludge(AS) and granular activated sludge(GAS) withdrawn from the bench scale bioreactor. Granular sludge shows much better settling properties than activated sludge because of their larger size and density. The settling velocity of the GAS was much higher than the settling velocity of AS, and then the settling velocity was decreased with sludge concentrations. The specific settling velocity of GAS and AS were 11.8 m/g·h and 0.65m/g·h at MLSS of 2650㎎/L, respectively. The oxygen uptake rate of GAS was much better 0.39 ㎏ O₂/㎏ MLSS·d than 0.15 ㎏ O₂/㎏ MLSS·d of AS. The particle size of the granular sludge was larger than activated sludge. The median diameter of GAS was 0.47mm while the diameter was 0.076㎜ for the AS. The elemental composition of granular sludge was investigated by energy dispersive X-ray spectroscopy. The GAS had a high sulfur content of 13.1%, calcium 18.5%, ferrous 11.2% of the sludge volume. This study shows that aerobic granules have a excellent settleability, large size, and high activity as compared to conventional activated sludge flocs. |
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| Key Words |
| Granular sludge, Settling velocity, Oxygen uptake rate, Size distribution, Aerobic granules |
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