基于微粒子辅助过滤原理,提出了一种新型膜污染控制方法,通过在膜表面形成一层疏松滤饼层控制膜污染.通过向原水中加入硅藻土颗粒,使其在膜表面形成一层疏松滤饼层,防止污染物直接在膜表面形成致密性滤饼层导致膜通量急剧衰减,从而达到缓解、控制膜污染的目标;进行周期性气一液混合清洗后,膜与硅藻土颗粒同时得到清洗再生.实验通过加入不同量、不同粒度硅藻土粒子验证膜污染控制效果.结果表明:硅藻土助滤剂对超滤过程膜污染控制效果与助滤剂粒径大小以及投加量有关.加入适量较大粒径助滤剂可有效降低过滤阻力,提高膜通量.而助滤剂粒径过小或投加量过多反而会增大过滤阻力,加剧通量衰减.投加2.0g/L粒径为35肚m的硅藻土助滤剂为实验最佳条件,可使相对膜通量和通量恢复率分别提高99/6和8%.
A novel process was constructed on the basis of micro-particle auxiliary filtration principle.Diatomite was added into the feed solution and a loose cake layer was tormed on membrane surtace, WhiCh could prevent contaminant from adhering on the membrane surface directly and forming a dense cake layer. Both of the membrane and diatomite particles could be regenerated by periodic gas-liquid mixed cleaning with the aim to limit membrane fouling. The effects of the size and dosage of the diatomite on the performance of the process were studied. The results show that the particle size and dosage of the diatomite play an important role in the the filter-aid function to reduce membrane fouling during UF process. The addition of the proper amount diatomite with bigger particle could decrease the filtration resistance and 2. 0 g/L diatomite with the size of 35 tan is the optimum value for this experiment. The relative flux increased 9% and the flux recovery rate enhanced 8% compared with UF process without diatomite.