Research On Migration And Transformation Of Specific Organic Pollutants And Reduction Of Toxicity Of Typical Coal Chemical Industry Wastewater

As the fundamental industry in China,coal chemical industry brings a lot of ecological and environmental issues along with the rapid development.Among these issues,the production of wastewater,which is complex,toxic and usually with high concentration,is the most severe and not only restricts the development of coal chemical industry,but also does harm to the environment.Therefore,it is important to build an appropriate analytical method for understanding the composition,remove characteristics and the potential impact to environment,thus making significance to wastewater treatment design and optimization.In this study,the pollutants production characters and transformation of pollutants in wastewater and toxic reduction are studied,main conclusions are as follows:(1)Different technologies of coal handling and coal characteristics had great influence on pollutants production in wastewater.Coal chemical wastewater from different processes showed great differences,while still have phenols,polycyclic aromatic hydrocarbons and nitrogen-containing compounds as main pollutants in common.It was also found that lots of pollutants were adsorbed on sewage sludge,showing that the adsorption was a potential way for pollutants migration.(2)Dissolved organic matters analysis of coking wastewater shows that there are large amount of aromatic compounds,and some of them are difficult to degrade in biology treatment.Humic-like substances,fulvic-like acid,proteinoids were also detected in coking wastewater,and most of these substances could be removed effectively by wastewater treatment process.As one of the most efficient treatment stages,aerobic treatment also produces large amount of soluble microbial substances which could contribute the increase of DOM.(3)High concentration of PAHs are detected in Lurgi coal gasification wastewater,and 4-5 rings PAHs are dominant PAHs.Most PAHs were removed efficiently in wastewater treatment process,however,analysis of sewage sludge shows that large amount of PAHs were absorbed on the sludge.Hydrophobicity and molecular size are the main factors of absorption.(4)Wastewater treatment process shows good capability for reducing acute toxicity to luminescent bacteria,COD,NH4+-N,phenols and PAHs could be the key toxic substances.Inhibition of wastewater to activated sludge is determined by the ratio of easily degradable substances and hard degradable substances.