Abstract:

The treatment process of coking wastewater often uses membrane technology to improve the quality of the effluent, meet the recycling standards, and achieve near-zero emissions. However, membrane fouling often leads to problems such as reduced membrane flux and damaged membrane components, thus increasing the cost of membrane process operation and maintenance. In order to deeply understand the membrane fouling in coking plant in Wuhai City, Inner Mongolia Autonomous Region, this study explored the water quality of the inlet and outlet water of the membrane treatment process and the composition of the membrane fouling layer. The results found that the membrane fouling was mainly caused by inorganic pollution, organic pollution and the combined pollution, and accompanied by biological pollution. The biofilm formed in the early stage had a high potential. The inorganic pollution was mainly composed of calcium sulfate, calcium fluoride and silicon scale. The organic pollution contained aromatic organic matter and humic acid as the main contributor. The formation of organic-inorganic pollution mainly involved cationic electrostatic shielding effect, the bridge effect of calcium ion and aluminum ion, hydrogen bonding between silica and humic acid. Finally, this study put forward targeted suggestions, which had guiding significance for the stable operation of the coking wastewater membrane process and the reduction of maintenance costs.

Key words: coking, wastewater, membrane fouling, fouling mechanism, mitigation measures

摘要：

焦化废水深度处理中常利用膜处理工艺提升排水水质，达到循环利用标准，实现近零排放。但膜污染常导致膜通量降低、膜元件受损等问题，因此增加膜工艺运营与维护费用。为深入了解内蒙古自治区乌海市某焦化厂膜处理工艺中膜污染情况，本文分别对膜处理工艺进出水水质和膜污染层组成进行了探究，综合分析发现该焦化厂膜污染主要由无机、有机以及两者耦合的复合污染为主，同时伴随生物污染，初期形成的生物膜具有较高的生物污染潜势。无机污染以硫酸钙、氟化钙、硅垢为主，有机污染含有芳烃类有机物，腐殖酸为主要贡献者。有机-无机复合污染的形成涉及阳离子静电屏蔽效应、钙离子、铝离子“桥梁”作用、二氧化硅与腐殖酸之间氢键作用等机制。本文结合以上情况，提出针对性建议，对焦化废水中膜处理工艺稳定运行、降低维护成本具有指导意义。

关键词: 焦化, 废水, 膜污染, 污染机制, 缓解措施