膜分离技术处理茶叶废水的研究

Study on the treatment of tea wasterwater using membrane separating technology

从茶叶中提取茶多酚后所产生的废水中有机物含量高,难以直接用生化法处理。首先采用超滤技术对茶叶废水进行浓缩,以除去胶体等大分子物质,滤液再经反渗透处理可除去小分子溶质。分别考察了操作时间以及膜污染清洗对超滤膜和反渗透膜水通量的影响,并对各阶段浓缩液及滤液的理化性质进行了比较分析。结果表明,经超滤及反渗透处理后,废水的COD由54642.32mg/L降到了96.80mg/L,COD去除率为99.82%,处理后的水质可直接排放或回收利用到茶叶提取工序,浓缩液可分别制成茶多糖及茶饮料产品,变废为宝,综合利用。

The tea wastewater from extracting polyphenols in tea contains high concentration of organic compounds, so it is difficult to treat them biochemically. In this research, the wastewater was firstly condensed by UF to separate the organic compounds with big molecular weight, such as the colloids. Secondly, the small molecule solvent was separated by RO. The influence of operation time and membrane cleaning on the water permeation capacity of UF and RO membrane were investigated. The physiochemical qualities of the water from different phases were analyzed. The results showed that the effluent COD was reduced to 96.80mg/L from 54642.32mg/L, and the removal efficiency reached 99.82%. The treated water could discharge directly or be reused for extracting tea polyphenols. The concentrated liquids from the UF and RO membrane could be made for tea amylose and tea beverage products, making use of the wastes that from tea industry.