Case study on wastewater treatment technology of coal chemical industry in China

Coal chemical energy industry has developed rapidly due to the primary position of coal in energy reserves in China. At the same time, coal chemical industry is also a high-water consumption industry. What’s more, coal chemical wastewater contains high concentration of phenols, NH3-N, and toxic and harmful substances. In the study, an all-round investigation on wastewater treatment technologies was conducted in projects of the coal chemical industry. These data were analyzed in detail from the aspects of coal-to-gas project, coal-to-oil project, and coal-to-olefin project. In pretreatment, phenol ammonia recovery device is the key section. At present, the process of first de-ammonia with gas stripping method and then de-phenolization with extraction method is mostly adopted in China. In microbiological treatment system, serious odor is diffused around the sewage treatment facilities. Thus, negative pressure extraction measures should be adopted in the microbiological treatment system. In addition, there is no suitable method for the treatment of concentrated brine and crystal salt, so it needs further study. Finally, this research can provide references for the problems of wastewater environment restriction existing in the long-term development of coal chemical industry.