The feasibility and economy of hollow fiber ( HF) membrane for ultrafiltration treatment of drinking water is highly dependent on the fouling behavior and corresponding cleaning operation. Pilot scale experiments with immersed HF membrane were conducted to investigate the effect of operating conditions of physical cleaning and chemical cleaning on the elimination of membrane fouling. The results showed; as compared with individual air bubbling or water backwashing, the combination of air and water cleaning could substantially improve the cleaning efficiency, as demonstrated by the increase of permeability restoration coefficient from 80% to 90%. To achieve the same cleaning effect (84. 3% permeability restoration) , 39% of the water consumption could also be reduced by the combined air bubbling at 22. 5 mV(m2 · h) and water backwashing at 140 L/( m2 · h) , when compared with individual water backwashing at 140 L/( m2 · h). The optimized cleaning condition was determined as water backwashing at 40 L/( m2 · h) combined with air bubbling at 45 m3/ (m2 · h) for 120 ~ 180 s. Under this condition, the permeability could be recovered to 93% of the initial value, with the water production rate higher than 94% . Furthermore, in the experiments, both HC1 (pH≈2) and NaClO (150 ～250 mg/L) cleaning were shown to be a-ble to remove the membrane foulants effectively; while NaOH was proved to be less efficient in the restoration of membrane permeability. An approximate logarithmic relationship was observed between the chemical cleaning efficiency and the soaking time of immersed HF membrane in the chemical solution.%中空纤维超滤膜的污染和清洗影响膜处理饮用水工艺的经济性及可运行性.在中试规模下研究了膜组件物理清洗和化学清洗操作条件对超滤膜污染去除效果的影响.试验表明,气水合洗与单独气、水洗方式相比,渗透率恢复系数由80％左右提高至90％以上；渗透率恢复系数同为84.3％时,合洗方式[水洗140L/(m2 · h)；气洗22.5 m3/(m2·h)]比单独水洗[140L/( m2·h)]减少了39％的自耗水量.得到本装置在运行工况下的优化清洗参数为:水洗强度80 L/(m2·h),气洗强度45 m3/(m2·h),合洗120 ～ 180 s,渗透率恢复到初始的93％,产水率大于94％.化学清洗采用pH值约为2的HCI溶液或150 ～ 250 mg/L的NaClO溶液,去除膜污染效果较好,NaOH清洗不佳；药洗后的渗透率恢复比与浸泡时间近似成对数关系.
展开▼
