The Exploration Of Deep Treatment Technology Of Coking Wastewater And Wastewater Containing Phenol

Coking wastewater is a kind of typical refractory organic wastewater, and contains high content of phenol, ammonia nitrogen, cyanide, benzene, pyridine, indoles and so on, with dark color, high toxicity, and stability.Currently in most of the coking plants coking wastewater was treated by biochemical method. After biological treatment, basic nitrogen and other pollutants are removed, but some heterocyclic or polycyclic organic pollutants are still in the water, and its COD value200-400mg/L is much higher than the national emisssion Standards. Deep treatment is one of the most important stage in coking wastewater treatment.How to greatly reduce the COD value of the coking wastewater is critical for the treatmentto reach the country-level. Therefore developing a new process of coking wastewater treatment with low-cost, high COD removal efficiency is more significant.First, using copperized-iron inner electrolysis technique, the decolorization of methyl orange simulated dye waste water had been investigated. The influences of pH value, dose of copperized iron, reaction time and initial concentration on the decolorization of methyl orange had been examined. And the process of the degradation of methyl orange was also monitored by means of in-situ cyclic voltamimetry. The results showed that:the optimum degradation could be obtained at pH value2to4,400g/L copperized iron dose and100min reaction time; the decolorization rate of methyl orange was with over96.0%. In-situ cyclic voltammetry ammetry showed that the oxidation-reduction reactions of methyl orange had occurred on the degradation process of methyl orange and it resulted in oxidation and reduction products.Second p-nitrophenol simulated wastewater was prepared and the degradation of it by copperized-scrap iron in constant current mode was researched. The dynamic potential scanning research showed that the copperized-iron as potential electrode has obviously catalytic oxidation for p-nitrophenol. This is helpful to get better decolorization effect than the pure copperized-iron inner mini-cell system. The degradation process conforms to pseudo-first-order reaction kinetics equation. The effect of current for degradation efficiency is relatively greater, and with the increase of the current density, the removal of p-nitrophenol increases also.At last, copperized-iron was used as electrode for advanced treatment of coking wastewater in different controlled condition to explore the optimal treatment scheme. The contrast experiment of internal electrolysis, constant current mode, constant potential mode and pulse current mode showed that in the pulse current mode, power consumption for the unit COD removal was much less than in the constant current and constant potential mode. And at the same time, the linear correlation between COD removal and treatment time of pulse current mode was the best. Therefore, pulse current mode is considered to be more operable in actual operation process. Adding oxidant to the solution at the pulse currents mode can further improve the degradation. After1h, the COD reaches43mg/L with removal of84%, and the efficiency of decolorization reaches91%, showing that the quality of output water has reached the1Grade discharge standards of water pollutants.Small-scale experiments by using the joint technology of pulsed electro-catalytic oxidation and micro-electrolysis to deal with the coking wastewater was performed, and a good decolorization effect of larger flow coking wastewater was achieved with a stable COD removal rate.