| China's printing and dyeing industry has many problems,such as large production of waste water and serious consumption of water resource s.With the development of the industry and wastewater treatment technology,the amount and proportion of recycling water in the printing and dyeing industry is gradually increasing,and the reverse osmosis membrane system is more and more widely used in the recycle water treatment of the printing and dyeing industry.However,the COD concentration of the concentrated water produced by the reverse osmosis membrane system is high and the chroma is high,so it is difficult to discharge up to standard without effective treatment.In this paper,reverse osmosis concentrated water was used in a printing and dyeing factory in zhejiang province,experimental study on the treatment of reverse osmosis concentrated water in printing and dyeing by electrocatalytic oxidation were done.The static sequential batch test was set up,stainless steel is used as cathode material,three anode materials were compared and selected,which are(1)stainless steel,(2)titanium-based lead dioxide coating and(3)titanium-based ruthenium and iridium coating.On this basis,the experiment device is designed and operated,the best electrode spacing is determined,and also the experimental study of target wastewater treatment is carried out within a certain range of parameters.Combined the experiment data,the pilot test equipment is constructed,and the key process parameters were optimized,and also the stability of continuous operation is verified.Meanwhile,according to the experimental results,process design and economic benefit analysis were carried out.It lays a good foundation for the final implementation of the p roject,and the data base is provided for the engineering application of electrocatalytic oxidation technology.The main conclusions are as follows:Static sequential batch experimental study shows that,while treating the reverse osmosis concentrated water by electrocatalytic oxidation,the treatment effect of titanium-based lead oxide coating was superior to stainless steel anode and titanium-based ruthenium-iridium coating anode.The COD removal rate was33.1%after 60 min,and it have higher processing efficiency.Meanwhile,the temperature increase of the treated wastewater is the least,and it is more suitable for practical engineering application.Electrode spacing comparison study findings that,the electrode spacing had no significant effect on COD removal.However,the electrode spacing is positively correlated with the power consumption.Based on practical application and technical requirements,the optimal electrode spacing is determined to be 25mm.Studies have shown that,the COD removal efficiency is positive correlationand with power consumption and current density,and it is negatively correlated with electrode surface load.Within the parameter setting range of the study,there is a risk of being above standard only under high electrode surface load-low current density conditions.In the pilot test,comprehensive consideration of wastewater treatment effect and energy consumption and other factors,the best parameter combination is determined to be current density of 100 A/m~2?electrode surface loadto of 128.8L/m~2·h to treating the reverse osmosis concentrated water with the upflow electrocatalytic oxidation device.Under these conditions,COD concentration of effluent was between 155 mg/L and 185 mg/L,the removal rate of CO D was between 32%and 39%,power consumption ranges from 3.2 kw·h/m~3 to 3.4kw·h/m~3.It can meet the actual needs of the project.Finally,the continuous flow test was carried out to verify the process stability.On this basis,engineering design and economic benefit analysis are carried out.The comprehensive treatment cost of the treatment of reverse osmosis concentrated water in printing and dyeing by electrocatalytic oxidation was 4.92 yuan per cubic meter.Energy consumption is a major component of the cost,accounting for about 67.6%. |
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