At present, the domestic technology for treating coal chemical wastewater mainly uses biochemical methods. The biochemical methods have a good removal effect on phenols and benzene substances in wastewater, but some quinolines, indoles, pyridines, carbazoles, etc. The poor treatment effect of refractory organics makes it difficult for the CODcr of the coal chemical industry to meet the first-class standard.
At the same time, the coal chemical wastewater has the characteristics of high color and turbidity after biochemical treatment (because it contains organic substances of various chromophores and auxiliary chromophores, such as 3-methyl-1,3,6heptatriene, 5 -Norbornene-2-carboxylic acid, 2-chloro-2-norbornene, 2-hydroxy-benzofuran, phenol, 1-methanesulfonyl-4-methylbenzene, 3-methylbenzothiophene, Naphthalene-1,8-diamine, etc.).
Therefore, to treat such coal gasification wastewater to achieve reuse or discharge standards, mainly to further reduce CODcr, ammonia nitrogen, color and turbidity and other indicators.