Study On Utilizing Ozone Treatment Of Coking Wastewater

Coking waste water is one of the comparatively popular industrial waste water with serious harmfully. It is difficult to treat due to its pollutant composition is complicated, its concentration and toxicity is high, its character is stable, and the current treatment methods have some limitation. Hence, it is quite necessary to investigate a new way to treat the coking waste water.This paper has a further study of the coking waster water of chemical plant in An Gang, adopting the technology of ozone oxidation, putting forward the theory of ozone oxidation, and investigating the following factor: the rate of ozone flow, reaction time and the original pH of waste water, which will be affected of the removal rate of COD, ammonia-nitrogen, volatile phenol, and chroma of coking waster water.The research shows: using ozone is effective to the removing of COD, volatile phenol and chroma of coking waster water. The removal rate can respectively amount to more than 91%, 99%, 98%. In a considerate sphere, with the increasing of the rate of ozone flow, the prolongation of reaction time, the removal rate of COD, ammonia-nitrogen, volatile phenol, and chroma of coking waster water will be increased. The original pH of waste water have a comparatively important effect to the ozone oxidation, when the pH is 10, the removal rate of COD can amount to 97.32%. The more the original pH of waste water, the higher the removal rate of ammonia-nitrogen. The effect of removing volatile phenol and chroma is not so obvious with the change of the original pH, however, it is also effective to remove. Under the optimum test conditions, using ozone oxidation treats the distilled ammonia waste water. COD reduces from 4610 mg/L to 123.6 mg/L, reaching the national secondary emission standards. Volatile phenol can reduce from 680 mg/L to 0.3 mg/L, reaching the national first discharge standard. Chroma can reduce from 780 times to 5 times, reaching the national first discharge standard. To know through gas chromatography characterized wastewater of pre and post reaction, ozone is a kind of strong oxidant, which can remove effectively the most organic compounds of coking wastewater. The investigation also shows: the single ozone oxidation cannot make ammonia-nitrogen well degrade, but we can consider connecting other ways (e.g.: chemic deposition method) to dispose. In a word, ozone oxidation is more effective to protect the environment as a new way to dispose of coking waster water .