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为了考察混凝/浸没式超滤膜工艺处理微污染地表水时影响跨膜压差增长的因素和对污染物的去除能力,采用实验室小试装置进行试验研究,保持工艺系统出水水量基本不变,观察不同运行工况下跨膜压差的变化,分析混凝剂投加量、混凝反应水箱水力停留时间、曝气强度对膜污染的影响,并考察采用低浓度碱液对膜进行在线清洗的效果,以及混凝/浸没式超滤工艺对污染物的去除效果。结果表明:混凝反应水箱的水力停留时间对膜污染影响较小,停留时间分别为10 min和0 min下运行,跨膜压差增长值接近;混凝剂投加量对膜污染影响较大,硫酸铝(以Al3+计)4 mg/L的投加量对膜污染改善比较好,继续增加投加量对膜污染的改善效果没有明显提高;曝气强度在20 m3/(m2.h)以下时,曝气量越大,对膜污染的改善越好;利用低浓度NaOH溶液进行在线化学清洗可以使跨膜压差得到有效的降低;该工艺的出水浊度保持在0.1 NTU以下,对CODMn和UV254的去除率分别能达到47%和54%。
In order to investigate the coagulation / submerged ultrafiltration membrane process of micro-polluted surface water, the factors that affect the growth of transmembrane pressure drop and the removal of pollutants, the use of laboratory small test device for experimental study to maintain the process of the basic water system does not The changes of transmembrane pressure drop under different operating conditions were observed. The effects of coagulant dosage, hydraulic retention time of coagulation reaction tank and aeration intensity on membrane fouling were analyzed. The membrane was treated with low concentration of alkali solution The effect of online cleaning, and the removal of contaminants by the coagulation / immersion ultrafiltration process. The results show that the hydraulic retention time of the coagulation reaction tank has little effect on the membrane fouling, and the residence time runs at 10 min and 0 min, respectively. The increase of the transmembrane pressure difference is close. The coagulant dosage has a great influence on the membrane fouling , Aluminum sulfate (calculated as Al3 +) 4 mg / L dosage is better to improve the membrane fouling, continue to increase the dosage of membrane fouling to improve the effect did not improve significantly; aeration intensity at 20 m3 / (m2.h) The higher the aeration rate, the better the improvement of membrane fouling; using low concentration of NaOH solution for online chemical cleaning can make the transmembrane pressure drop is effectively reduced; the water turbidity of the process is maintained below 0.1 NTU, for The removal rates of CODMn and UV254 can reach 47% and 54% respectively.