Evaporation-Ozone Oxidation Coupling Technology To Treat High Salinity And High Concentration Organic Wasterwater

High-salinity and high-concentration organic wastewater has two important characteristics:high salt content and high COD,so conventional treatment methods can not work.In this paper,the idea of combination of evaporation and ozone oxidation is first proposed for the treatment of high-salinity and high-concentration organic wastewater.Based on this idea,a set of feasible treatment methods is designed:Evaporation–Ozone oxidation coupling technology to treat high salinity and high concentration organic wastewater.This method,as a pretreatment method,is designed to remove inorganic salts and organic matter in wastewater through the combination of evaporation and ozone oxidation.This method can improve the biodegradability of wastewater to meet the requirements of biochemical treatment.In this process,the effects of ozone dosage,evaporation rate,initial pH,gas residence time,activated carbon usage,activated carbon particle size,activated carbon addition mode and activated carbon reutilization on wastewater treatment were investigated.It is effective to use this method to treat high salinity and high concentration aniline compound wastewater.The experimental results show that the use of ozone and COD removal rate is positively correlated within a certain range,that is,COD removal rate increased with the increase of ozone usage.However,the COD removal tends to be steady when ozone usage exceeds a certain value.Evaporation rate had a significant effect on COD removal rate and BOD₅/COD value of wastewater,COD removal rate and BOD₅/COD value reached 72.9%and 0.107 respectively at the maximum evaporation rate（evaporation time:60min）.The gas residence time mainly determines the reaction time of the mixed gas.Within a certain range,the COD removal rate and BOD₅/COD value increase with the residence time of the gas,exceeding the optimum residence time 14.13s,COD removal rate and BOD₅/COD Value can`t increasing.The way of ozone access affects the wastewater treatment effect mainly through its utilization rate.The higher the ozone utilization efficiency,the better the treatment effect,but other factors are also taken into consideration.In this method,activated carbon still has the function of catalyzing ozone decomposition to produce·OH,and the better the wastewater treatment effect is as the amount of activated carbon increases,but the treatment effect decreases when the amount of activated carbon exceeds the optimum value.The best pH in this experiment was 11.0.Activated carbon is still a good catalyst after repeated use.It is effective to use this method to treat high salt and high concentration of pesticides production wastewater.The experimental results show that COD removal rate increases with the increase of ozone consumption within a certain range.However,the COD removal rate tends to be stable when the amount of ozone used exceeds a certain value,and the optimum amount of ozone is set to 7.78g/L in consideration of the cost and the treatment effect.Under alkaline conditions the treatment effect is better than acidic conditions,the best wastewater treatment pH of 9.0.Evaporation rate has a significant effect on COD removal rate and BOD₅/COD value of wastewater,COD removal rate reaches 77.5%at the maximum evaporation rate（2.14mL/min）.The residence time of gas determines the reaction time of the mixed gas.Within a certain range,the COD removal rate and BOD₅/COD value increase as the gas residence time increases.When the time exceeds the optimum residence time continues to increase,COD removal and BOD₅/COD values are not increasing.Activated carbon has the function of catalyzing ozonolysis,which is mainly caused by different specific surface area.With the increase of activated carbon,COD removal rate and BOD₅/COD of wastewater increased.However,when the amount of activated carbon exceeded the optimum value,the treatment effect decreased.The best dosage of activated carbon in this experiment was3g.The smaller the activated carbon particle size,the more conducive to catalysis,but the particle size is too small to be easily recovered,so the optimal particle size range is set to 1-1.5 mm.The catalytic effect of alkaline modification of activated carbon is better than that of acidic modification,which is due to the increase of groups on the surface of activated carbon which are favorable for catalytic ozone decomposition after basic modification.Activated carbon is still a good catalyst after repeated use.