投加沸石粉活性污泥搅拌参数优化及其对离子交换速率的影响研究
Optimization of stirring factors of activated sludge with zeolite additionand its effect on velocity of ion exchange
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摘要: 在0.3 m×0.3 m×0.36 m方形搅拌槽中初步探讨了不同的搅拌器类型、安装高度以及曝气强度对投加了沸石粉的高浓度活性污泥悬浮状态的影响，并根据固液悬浮理论确定了最佳的搅拌参数。同时，进行了不同搅拌速率下沸石对污水中氨氮的离子交换动力学研究。结果表明在无曝气的情况下，选用三叶推进式搅拌器，搅拌器离底高度为1/3搅拌器直径时所需要的临界搅拌速率最低。曝气有助于反应池中污泥的悬浮，对于30 g/L的污泥，当曝气强度由10 m3/(m2·h)增大1倍时，临界搅拌速率降低了50%。搅拌速率为120 r/min时，沸石对污水中氨氮的离子交换速率受膜扩散过程控制，当其增大为180 r/min时，其控制步骤为粒内扩散，沸石粉活性污泥达到完全均匀悬浮的临界搅拌速率不足以满足传质的要求，需增大一定程度。Abstract: The effects of different types of agitator, the fixing height and the intensity of aeration on the sludge of high concentration that adding zeolite in a square stirred tank (0.3 m×0.3 m×0.36 m)were studied in order to ascertain the optimum stirring factors. And according to the correlative theory, the optimum factors of stirring were ascertained .Meanwhile, the kinetics of the ammonium removal on the zeolite under different stirring speed was studied. It demonstrated that without aeration the best type of agitator is three-blade impeller and the height is 1/3 diameter of impeller. Aeration can improve the suspension of sludge. Taking the activated sludge with concentration of 30 g/L for an example, the critical rotating speed was reduced 50% when the aeration intensity increased by one time. The experiments also showed that the velocity of ion exchange under 120 r/min was controlled by film diffusion, which was changed into intraparticle diffusion control when the stirring speed was enlarged to 180 r/min. The critical rotating speed should increase in order to meet the activated sludge with zeolite addition mass transfer.
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