Effects of cycling time on the performance of granular sludge in sequencing batch reactors (SBR) were evaluated. Two reactors, reactor 1 (R1) and reactor 2 (R2) was introduced to industrial wastewater with varying chemical oxygen demand (COD) loadings from as low as 0.01 to 0.28 kgCOD/m3/d. However granules in R1 utilizes cycling time of 24 hours whilst R2 utilizes cycling time of 4 hours. The overall performance for both reactors were excellent, where COD removal efficiency was kept at about 78 % to 98 % removal. Although higher COD removal was observed for both reactors, granulation did not occur in R1 when applying cycling time of 24 hours. In contrast to R2, decrement of cycling time to 4 hours promotes the growth of dense and structured sludge granules.
