摘要
搭建了以微砂为载体的加载絮凝(BF)与超滤(UF)联用工艺的小试装置,结合微砂投量对膜滤效能和膜污染的影响,考察了采用柠檬酸、NaOH和NaClO溶液单独清洗时受污染膜的通量衰减、污染可逆性和通量恢复率等特征。结果表明,BF阶段投入适量微砂,可在超滤膜上形成一层具有特殊结构且透水性能良好的滤饼层,有利于UF过程中提高膜比通量、减缓水洗后膜污染及优化膜滤出水水质,但无法有效抑制不可逆膜污染的累积;选用不同类型和浓度的药剂对受污染膜进行单独化学清洗后,碱洗效果优于氧化剂清洗,而酸洗在3种化学清洗方法中表现最差,究其原因是酸、碱及氧化剂去除不同种类污染物的能力各异,致使不可逆污染清除程度存在显著差别。此外,还初步解析了不同化学清洗条件减缓膜污染的作用机理,并指出在实际操作过程中需同时兼顾化学清洗剂的种类及浓度,以实现清洗效果的最优化。
A lab-scale experimental device was established for the combined process of ballasted flocculation(BF)and ultrafiltration(UF)using microsand as the carrier.The effect of the microsand dosage on the ultrafiltration efficiency and membrane fouling was analyzed,and the flux attenuation,fouling reversibility and flux recovery rate of the contaminated membrane were investigated when citric acid,NaOH and NaClO solutions were used for separate cleaning.A cake layer with special structure and good water permeability was formed on the UF membrane by adding appropriate amount of microsand in the BF process,which was conducive to improving the membrane specific flux,slowing down the membrane fouling after washing and improving the effluent quality during the UF process.However,it could not effectively inhibit the accumulation of the irreversible membrane fouling.Different types and concentrations of agents were selected for separate chemical cleaning of the contaminated membranes.The performance of alkali cleaning was better than that of the oxidant cleaning,while the acid cleaning had the worst cleaning performance among the three types of chemical cleaning.The reason was that the ability to remove various kinds of pollutants for each cleaning agent was quite different,leading to a significant difference in the degree of irreversible fouling removal.In addition,the mitigation mechanisms of the membrane fouling under different chemical cleaning conditions were preliminarily revealed,and it was pointed out that the type and concentration of the chemical cleaning agent should be taken into account in the actual operation to optimize the cleaning performance.
作者
贺维鹏
屈梦军
施周
郑飒
吴慧英
李波
HE Wei-peng;QU Meng-jun;SHI Zhou;ZHENG Sa;WU Hui-ying;LI Bo(Key Laboratory of Building Safety and Energy Efficiency<Ministry of Education>,Hunan University,Changsha 410082,China;College of Civil Engineering,Hunan University,Changsha 410082,China;Changsha Planning&Design Institute Co.Ltd.,Changsha 410007,China)
出处
《中国给水排水》
CAS
CSCD
北大核心
2021年第19期33-39,共7页
China Water & Wastewater
基金
湖南创新型省份建设专项经费资助项目(2019SK2281)
国家自然科学基金资助项目(51308199)。
关键词
加载絮凝
超滤
膜污染
化学清洗
微砂
ballasted flocculation
ultrafiltration
membrane fouling
chemical cleaning
microsand
