Study On Pretreatment Of Dyeing Wastewater By Ozonated Internal Electrolysis Process

Dyeing wastewater contains a large amount of dyes and various additives,which generally have problems of high color and poor biodegradability.If the biological method is used to treat dyeing wastewater directly,the effluent is easy to exceed the standard's requirement.In this regard,in order to effectively improve the biodegradability of wastewater by reducing color and toxic substances of the water,the wastewater was pretreated before biochemical treatment.Therefore,this study compared and analyzed the treatment efficiency of three processes?OIE,IE,O₃?on two kinds of simulated dyeing wastewater.The effects of different factors in ozonated internal electrolysis?OIE?process on simulated wastewater treatment were researched by single factor experiment.The optimal operation parameters of OIE process for real wastewater treatment were obtained by orthogonal test and single factor experiment.In order to investigate the effect of the process on the treatment of the real wastewater under the condition of dynamic continuous operation,the experiments of filler reuse and continuous operation of the OIE process were carried out on the basis of the previous experiments.The study found that the internal electrolysis?IE?and ozonation?O₃?processes were not as effective as the OIE process in the treatment of the two simulated dyeing wastewaters.OIE process can effectively reduce the COD,color and aniline of eriochrome red B?ERB?and remazol brilliant blue R?RBBR?simulated wastewater,furthermore improve its B/C ratios.The COD removal efficiencies of ERB wastewater and RBBR wastewater by OIE process can reach 69.10%and 42.13%respectively.The color removal efficiencies of ERB wastewater and RBBR wastewater by OIE process can reach 97.67%and89.90%respectively.The aniline removal efficiencies of ERB wastewater and RBBR wastewater by OIE process can reach 87.96%and 64.66%respectively.The decrease of the initial dye concentration,the increase of the amount of fillers and ozone,the increase of the initial p H will make the OIE process treatment of simulated wastewater better.The influence of each factor on the removal of dye concentration in ERB wastewater was small,and the influence on RBBR wastewater was greater.The optimal operating parameters of OIE process in intermittent operation were as follows:p H=11,gas flow was 0.6 L/min,the amount of filler was 750 g/L,ozone gas concentration was 4.94 mg/L.Under this conditions,the B/C ratio of the real wastewater can be increased from 0.12 to about 0.60,the color and COD removal efficiencies can reach more than 98%and 50%,respectively.In addition reuse of fillers can maintain removal efficiencies.When the OIE process is used to treat real wastewater in a continuous operating state,the color removal rate can be stabilized at about 84%,and the B/C ratio of the effluent can be maintained above 0.4.In summary,OIE process as a pretreatment process for dyeing wastewater can effectively remove the color of the wastewater,improve the biodegradability of the wastewater,as well as have an ideal treatment effect in the continuous operation process.This process has a good treatment effect on dyeing wastewater which have high color and toxicity,but low COD and SS.This process is worthy of popularization and application in the treatment of dyeing wastewater.