混凝沉淀/MBR组合工艺中膜污染清洗方法的研究

针对混凝沉淀预处理/膜生物反应器组合工艺,采用能谱分析和傅里叶红外光谱对膜表面的污染物进行分析,并对不同清洗剂的清洗效果进行了探讨。结果表明,酸性清洗剂对膜的清洗效果较好,膜表面的无机污染物基本被去除,但不能完全有效地去除膜表面的有机污染物;NaOH和NaClO的清洗效果不佳。从酸碱交替清洗效果来看,先酸洗后碱洗过程的膜恢复率比先碱洗后酸洗过程的高8%。对膜污染过程进行推测,胞外聚合物(EPS)和残留的絮凝颗粒一并沉积并吸附在膜表面,形成以有机物为主体、粘结性很强的凝胶层(内层);在混凝沉淀预处理长期运行条件下,凝胶层由内向外又不断吸附了无机盐类物质,凝胶层(外层)逐渐过渡为以无机污染为主,期间还存在无机物和有机物的络合,导致单纯采用碱和氧化剂的清洗效果不佳。

Membrane Fouling Cleaning in Coagulation Sedimentation/Membrane Bioreactor Process

SEM-EDS and FTIR were applied to analyze membrane foulants in coagulation sedimentation/membrane bioreactor process,and the cleaning effects of different clearing agents were investigated.The results showed that the acid cleaning agents achieved superior membrane cleaning effects,removing most of inorganic foulants,but not organic foulants.The cleaning effects of NaOH and NaClO were poor.In the alternating acid-alkali cleaning experiment,the membrane recovery ratio of acid-alkali cleaning was 8% higher than that of alkali-acid cleaning.The results arrived at a fouling mechanism in which EPS and flocculated particles were first accumulated on the membrane and formed inside the organic gelatin layer.Then,inorganic materials were adsorbed by the gelatin layer to form an outside inorganic foulant layer due to the complexing effect.Therefore,alkali and oxidant cleaning did not play a good role in foulant removal.