Study On The Treatment Of High Concentration Unsaturated Polyester Resin Wastewater

Unsaturated polyester resin has excellent mechanical properties and flexible process performance.It is widely used in many production industries.Unsaturated polyester resin wastewater,as a typical high concentration organic wastewater,has high toxicity and is extremely difficult to degrade.If direct discharge is harmful to the environment,it will be very harmful.The development of China's resin industry is seriously restricted.This paper in order to solve these problems,the technology of distillation,cooling and ozone is applied to treat unsaturated polyester resin wastewater,which reduces the concentration of organic matter and inorganic substance in wastewater,reduces the toxicity of wastewater,and improves its biochemical properties.By comparing the three sets of experiments of distillation,cooling,distillation and cooling,it was found that there was no obvious effect on distilling or cooling treatment of unsaturated polyester resin wastewater.However,after the combination of distillation and cooling,the conductivity of wastewater decreased by 27.7%,TDS decreased by 58.4%,CODcr dropped 25.4%,pH increased from 2.23 to 4.03,BOD5 decreased 30.9%.The cis-butenedioic anhydride,one of the raw materials for the production of unsaturated polyester-resins,will precipitate out in the form of a large amount of white flocs,while the pungent odor of the wastewater is significantly reduced.The physical method of distillation-cooling is simple,effective,pollution-free,and can also reduce production costs.Ozone oxidation method was used to further treat unsaturated polyester resin wastewater after distillation and cooling treatment.The effects of ozone concentration,reaction time and initial pH of wastewater on ozone treatment were investigated.Ozone's best reaction conditions were as follows:ozone concentration was 70 mg/L,treatment time was 60 min,and initial pH of wastewater was 9.However,the TDS and CODcr of the wastewater can be effectively reduced by 66.4%and 53.5%,respectively.The ozonation reaction accords with the first orderkinetic equation under the best reaction conditions,and the rate constant K=0.00875.In order to further enhance the effect of ozone on the treatment of unsaturated polyester resin wastewater,a small electrolysis cell with electrocatalytic ozonation was designed.The small test cell was analyzed by numerical simulation.When the number of pores on the intake pipe of the electrolyzer is 11,ozone can enter the electrolyzer more evenly,increasing the gas concentration on the surface of the plate,and making the flow field in the electrolytic cell circulate.At the same time,there is no dead zone in the flow field of the electrolyzer.The strong oxidizing substances generated by electrocatalytic ozonation can be mixed evenly with the wastewater.