[Cultivation of aerobic granules by a method of alternative feed loading]

The formation process and morphological and physicochemical properties of aerobic granules were examined in a SBR system by a method of alternative feed loading. The results showed that the aerobic granules could be quickly and effectively cultivated using the alternative feeding COD 400, 800, 1200 mg/L [feed loading 0.96, 1.92 and 3.84 kg/(m3 x d)] when other conditions were fixed. The developed granules of the reactor were maintained in MLSS 20-22 g/L and SVI 14-16 mL/g. The average size of completely granular particles was 613.6 microm in diameter. The cocci occupied mainly in outer layer of granules, and both cocci and rods existed in inner layer of particles. The granules reached 95% COD removal and 97% NH4+ -N-removal simultaneously. The analysis of FISH showed AOB was distributed in outer surface of aerobic granules, and NOB existed in outer and inner layer small amounts of aerobic granules.