3. Results and discussion
3.1. Formation mechanism of aerobic granular sludge at different high temperatures and morphology observation
This study presents the findings regarding the effect of high temperature on granule formation and morphology as summarized in Table 2. At the beginning of the experiments, the fresh sludge appeared as irregular, fluffy and having loose-structure morphology with the presence of filamentous microorganisms. Towards the end of the experiments, the sludge color slowly turned from dark brown to yellowish brown. The loose flocs-like sludge was apparently broken up into small size particles during early experimental period (first week) under vigorous shaking conditions.