中国不但水的供应有问题，水的污染是将来生存的关键。水的污染有两类：一类是自然污染，另一类是人为污染，而后者是主要的。人为污染是人类的生活和生产活动中产生的污水对水资源的污染，包括生活污水、工业废水和农田排水等。
Not only is there a problem with water supply in China, but water pollution is the key to survival in the future. There are two kinds of water pollution: one is natural pollution, the other is man-made pollution, and the latter is the main one. Man-made pollution is the pollution of water resources by sewage produced in human life and production activities, including domestic sewage, industrial wastewater and farmland drainage.
其中，又以工业废水带来的污染为最甚。化工废水排放总量占全国工业废水排放总量的19%，居各行业之首。而目前化工行业工业废水排放达标率只有52.9%。化工废水的基本特征为极高的COD、高盐度、对微生物有毒性，是典型的难生物降解废水，化工废水经过处理才能排放已成为人们的共识。
Among them, the pollution caused by industrial wastewater is the most serious. The total discharge of chemical wastewater accounts for 19% of the total discharge of industrial wastewater in China, ranking first in all industries. At present, the discharge rate of industrial wastewater in chemical industry is only 52.9%. The basic characteristics of chemical wastewater are high COD, high salinity and toxicity to microorganisms. It is a typical refractory wastewater. It has become a common understanding that chemical wastewater can be discharged only after treatment.