Study Of Treatment Technology Of Refractory Organic Pollutants In Coking Wastewater

Coking wastewater is a kind of typical refractory organic wastewater. The componets of coking wastewater with high concentration of organic pollutants, color, and toxics are very complex, such as high content of phenol, ammonia nitrogen, cyanide, benzene, pyridine, indoles and so on.Currently coking wastewater in most coking plants is treated by biochemical method. After biological treatment, phenol and other pollutants are basicly removed, but the removal rate of chroma and COD is not favorable. Some heterocyclic or polycyclic organic pollutants are still in the water, so the COD is difficult to meet the national emisssion standards. Therefore developing a new process of coking wastewater treatment with low-cost, high COD removal efficiency is very significant.Firstly, chelation technique was used to degrade the coking wastewater. And the removal efficiency of COD and chroma was researched and the composition change in coking wastewater before and after treatment was analyzed by GC/MS. Research showed that organic matter in coking wastewater reduced from59to18species by chelation technology, particularly those containing lone pair electrons of N, S, P, As, etc have significantly reduced. And the removal efficiency of COD and chroma was obviously better than ordinary oxidation method.Secondly, electrochemical catalytic technology with activated carbon basket as the anode was used to degrade the coking wastewater. And the facts of reaction time, plate spacing, current density, additive on the effect of COD removal efficiency were studied. Then the composition change in coking wastewater before and after treatment was analyzed by GC/MS. The results showed that the optimal reaction conditions for the COD removal efficiency of90%was obtained in80min at pH5and300mA current density, having to meet emission standards at the national level. Finally small-scale electrochemical experiments using activated carbon basket as anode were carried out to deal with coking wastewater continuously, and a good degradation effect for larger flow coking wastewater was achieved with a stable COD and chroma removal rate. The apparatus with low operating cost can be service the industry in future and can achieve economic value.