印染废水污染膜的组合清洗技术研究

Study on the composite cleaning technology of the membrane fouled by dyeing textile wastewater

不同进水水质及运行管理水平下,污水处理膜生物反应器(membrane bioreactor,MBR)的膜污染速度、膜面污染层组成及特性不同,污染膜的清洗方法亦不同.本研究针对实际印染废水处理工程中的污染膜,开展清洗剂用量及组合清洗技术研究,综合评价清洗前后膜性能参数的变化,以期获得可用于实际废水处理工程的最优清洗方案.结果表明,质量分数0.5%次氯酸钠在20L/m2时清洗效果最好,质量分数3%柠檬酸在40L/m2时清洗效果最好;超声与柠檬酸的清洗作用相似,均为提高膜污染层的孔隙率;最优清洗方案为先超声1h,然后质量分数0.5%次氯酸钠清洗3h,最后3%柠檬酸清洗3h;清洗后的膜孔隙率、平均孔径及最大孔径等特征参数与新膜相比未发生明显变化;X射线能谱(Energy Dispersive X-Ray Spectroscopy,EDX)分析表明,印染废水污染膜表面以有机物污染为主,兼有少量无机污染,清洗后膜表面以C和F元素居多,未见O元素和金属元素峰,表明有机物和无机物(含金属氧化物)均得到很好去除,清洗效果良好.

Under different types of wastewater and operational management,membrane fouling rate,the composition of fouling layer and its property as well as the cleaning method are variable.Targeting at fouled membranes treating dyeing textile wastewater,the dosage of cleaning agent and suitable combined cleaning technology were explored,and the properties of cleaned membrane were evaluated.It would be helpful to obtain the optimal cleaning solution for practical wastewater treatment plant.The results showed that 0.5%sodium hypochlorite with a dosage of 20L/m2 and 3%citric acid with a dosage of 40L/m2 were optimal.The mechanisms of ultrasonic and citric acid cleaning were similar,which were to improve the porosity of fouling layer.The optimal cleaning strategy was to ultrasonically clean for 1h,immerse fouled membranes in 0.5% sodium hypochlorite solution for 3hand finally in 3% citric acid solution for 3 h.The membrane after cleaning exhibited similar appearances and properties as new membrane.Energy dispersive X-ray spectroscopy（EDX）analysis showed that the foulants on/in the surface of the fouled membrane were mainly organic matters with a small amount of inorganics.The main elements on/in the surface of the cleaned membrane were cabron and fluorine elements,and oxygen and metal elements were totally removed.It showed an excellent cleaning efficiency.