Experimental Study On The Treatment Of The Secondary Sewage Of Refinery Wastewater By Micro-electrolysis-fenton Technology

Yellow River has beared a huge pressure with large population,resource and environment. The water environment is aggravating. The excessive use of Yellow River and the wanton discharge of waste water have made our mother river scarred and overwhelmed. The oil refinery located on the side of Yellow River has outstanding resource strategic position, making great contribution to our country,but at the same time,it causes damage to Yellow River.The actual turbidity, CODC4and electrical conductivity of effluent water of the refinery have a large fluctuation range.The CODCr of secondary effluent is about130mg/L.It will produce a serious impact if the water is emissioned directly,and threaten the security of drinking water and the yield of industry and agriculture seriously.In addition,the secondary effluent has a large displacement,it will be a great pity if the water is emissioned directly. So,this paper focuses oc the reuse of this water,and is expected to reduce the total amount of pollutants in yellow river,lessening the pollution contribution of this plant,and then improving the utilization efficiency of water resource constantly.Micro-electrolysis and Fenton oxidation which are used to treat waste water are convenient to operate and easy to manage, with advantages of low operating cost and small footprint. Biodegradability of waste water treated by micro-electrolysis and Fenton oxidation always has a Significantly improvement. The packing of micro-electrolysis is the old scrap iron or iron shavings,and the activated carbon also can de replaced by coke or flyash ect. Materials used in the process are easy to get, which conform to the principle of using waste to treat waste.With the above-mentioned reasons,this paper focuses on the mechanism, characteristics and application in waste water treatment arear of micro-electrolysis and Fenton oxidation. Also the paper determines the degree of primary and secondary of influence factors by orthogonal test, and then determined the best parameters of each influence factor by single factor experiment.Then,this paper combines these two processes based on orthogonal test and single factor experiment,carries out the connection experiment of micro-electrolysis+Fenton and couplles experiment of micro-electrolysis+Fenton. By the analysis of contrast, this paper selects a relatively optimal combination process and then carries out a laboratory dynamic experiment, to make a further study of the running stability of the process.Single micro-electrolysis experiment suggests that:when the weight ratio of iron versus carbon is3/2, the dosage of Fe is150g/L,reaction time is2.5hours, pH value is3, Particle size of Fe is about2-3mm and the aeration amount is5L/min, and the removal efficiency of CODCr will reach the highest leval,about74%; Single Fenton oxidation experiment suggests that:when the dosages of30%H2O2and FeSO4·7H2O are0.4mL/L and0.5mL/L respectively, pH value is4, reaction time is2hours, the removal efficiency of CODCr will be about72.7%; the connection experiment of micro-electrolysis+Fenton shows that:when pH value is3, the weight ratio of iron versus carbon is3/2, the dosage of Fe is150g/L, reaction time is2.5hours, Particle size of Fe is about2～3mm and the aeration amount is5L/min of micro-electrolysis unit,and the dosage of30%H2O2is0.4mL/L, reaction time is1hour of Fenton oxidation unit, the effect of connection experiment will be the best.The coupling experiment of micro-electrolysis+Fenton shows that:when pH value is3, the weight ratio of iron versus carbon is3/2, the dosage of Fe is150g/L, Particle size of Fe is about2-3mm and the aeration amount is5L/min the dosage of30%H2O2is0.3mL/L and reaction time is90min,it will have a best treatment effect. Through the analysis and comparison,and selecting, the coupling process of micro-electrolysis+Fenton to carry out the laboratory dynamic experiment,the result shows that using coupling process to treat the secondary effluent of wastewater of refinery and chemical enterprises will receive a good removal effect of CODC4, and the removal efficiency of CODCr is about79%.During the experiment, quality of effluent water and the operational stability are good,thus we can use this process to treat the the secondary effluent of wastewater of refinery and chemical enterprises for reclamation and reuse of waste water.In addition,this paper tests the indirect producing rate of-OH with1,10-Phenanthroline-Fe2+spectrophotometry during the single Fenton oxidation experiment,and finds out that the removal of COD in waste water can be reflected by the indirect producing rate of·OH.