| Aerobic granular sludge technology is a new type of waste-water treatment technology developed in recent years, which is based on the research of anaerobic sludge granulation. Granular sludge is a granular microorganism which is formed in the water treatment system. It is formed by the self-aggregation of microorganisms. It can effectively remove the COD, ammonia nitrogen, heavy metals, refractory organic matter and so on. Compared with traditional activated sludge, it is not easy to sludge bulking, with good settling performance, the effluent separation purification is simple, the efficient microbial retention in the reactor, and does not need to set the secondary sedimentation tank and sludge recirculation equipment, low construction cost and operation cost, good biological activity, biomass, with good resistance to shock loading capacity, can effectively solve the problem of flocculent sludge in water treatment. In recent years, the formation mechanism, influencing factors and cultivation conditions of aerobic granular sludge have become a hot research topic at home and abroad. This topic in the SBR reactor seeded with flocculent activated sludge, the use of simulated domestic waste-water aerobic granular sludge cultivation, influencing factors on the cultivation of aerobic granular sludge, such as water COD load, surface rising gas velocity, hydraulic retention time(HRT) etc., and to study the treatment effect of sewage.During the SBR operation, when the in fluent COD load is 3.84~4.08 kg/(m3·d), the surface rising gas flow rate is 2.0~2.39cm/s, the hydraulic retention time is 4h, the aerobic granular sludge is cultivated. In the experiment, the method of increasing the COD loading and hydraulic shear stress of the in fluent, and gradually reducing the settling time of the sludge to cultivate the aerobic granular sludge. In the course of culture, COD was measured every 2 days, the removal rate of COD was calculated, and the in fluent COD concentration was increased when the removal rate was above 90%. SVI, particle size and MLSS were measured every 5 days. Appearance morphology was observed every 10 days. The mature aerobic granular sludge is yellow, the shape is round or oval, and there are filamentous bacteria around the particles. The particle size of 2~6mm was SVI in 55ml/g, MLSS was 4600mg/L, and the average settling velocity was 35m/h. The simulated waste-water was treated by aerobic granular sludge. The COD of simulated waste-water is 1800mg/L, NH3-N is 90mg/L, the operation period is 4h,and the removal rate of aerobic granular sludge to COD, NH3-N is 90.8% and 94.6%, respectively. |
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