Study On The Treatment Of Waste Emulsion By Combined Process

Waste emulsion is a national hazardous waste with high oil and organic content and poor biochemical properties,which can cause serious pollution to the environment if not treated properly,and is a difficult problem for industrial wastewater treatment.In this study,a combined process of Fenton oxidation and sequential batch reactor was used to treat waste emulsions.Based on the single-factor experiment,the chemical oxygen demand（COD）removal rate was used as the index,and the response surface method was used to optimize its reaction conditions.The effects of four factors,namely initial p H,ferrous sulfate dosage,n（H₂O₂）:（Fe SO₄·7H₂O）and reaction time,on the Fenton reaction were investigated to determine the optimal process conditions for Fenton oxidation treatment of emulsion.The SBR system was used to treat the Fenton effluent,and the reactor start-up process was investigated to examine the effects of different operating conditions on COD removal by SBR.The main conclusions are as follows.A significant quadratic regression model was obtained to predict the optimal reaction conditions.The fitted experimental data model statistics showed that the F value was 50.77,P<0.0001,and the order of influence of single factors on COD removal was:initial p H>n（H₂O₂）:（Fe SO₄·7H₂O）>ferrous sulfate dosage>reaction time,and among the compound factors,the interaction effect of n（H₂O₂）:（Fe SO₄·7H₂O）and ferrous sulfate dosage was the strongest.The response surface optimization predicted the best reaction conditions as follows:p H value of 2.83,ferrous sulfate dosage of 5.74g/L,n（H₂O₂）:（Fe SO₄·7H₂O）of 22.31,and reaction time of 45.09min.The theoretical COD removal rate under this condition was 75.74%,and the actual COD removal rate was 76.14%,with little deviation.The domesticated activated sludge was able to adapt to the waste emulsion feed water with good degradation effect.Based on the culture domestication,the optimum operating conditions of the SBR reactor for waste emulsion treatment were determined:the sludge concentration was2800 mg/L,the initial concentration of waste emulsion was 5000 mg/L,and milk was used as an additional carbon source with a dosage of 5 m L/L.The COD removal rate of the SBR reactor under this condition was 92.60%,and the effluent value was 211 mg/L.The combined Fenton-SBR process has good degradation effect on waste emulsion,and after pretreatment by Fenton method can improve the biochemical properties of wastewater,the biological treatment efficiency is improved,and the effluent can reach the tertiary standard in the Comprehensive Wastewater Discharge Standard（GB8978-1996）.The study lays a certain foundation for the further expansion and practical application of the process.