| The main subject of the article was committed to a simulating lab test on wastewater treatment technology of MDF industry.After a comprehensive analysis of wastewater samples,coagulation method,activated carbon adsorption method and Fenton oxidation method were used to pretreat the wastewater to explore the best pretreatment method and its optimization condition.Then,according to the water quality of the wastewater after pretreatment,the ultrafiltration separation technology and Fenton oxidation technology were used to form a combined process to conduct deep treatment to wastewater of MDF industry.At the same time,cleaning tests were carried out aiming at the problem of ultrafiltration membrane fouling,and the comprehensive benefit of the Fenton-Ultrafiltration combined process was analyzed.Through the experimental study and analysis,the main conclusions are as follows.(1)The wastewater of MDF was mainly derived from the process of wood chips washing and grinding.The test results showed that this kind of wastewater was seriously polluted,which compared with the national sewage comprehensive emission standard,the COD exceeded 280 times,SS exceeded 140?170 times,Chroma exceeded 20?40 times and NH3-N exceeded 20?27 times.(2)Fenton oxidation method was the best by comparising the actual effect of pretreatment methods of coagulation,activated carbon adsorption and Fenton oxidation,which showed strong decontamination ability,less timeness and high efficiency.Its optimum reaction conditions were as follows:the initial reaction pH was 5,the dosage of FeSO4 ·7H2O was 0.03mol·L-1,the[H2O2]/[Fe2+]molar ratio was 6:1 and the reaction time was 120min.Under the optimized conditions,the Fenton oxidation method was used to pretreat thewastewater of MDF industry,and the COD and Chroma removal rate were 78%and 80%respectively.(3)Fenton oxidation technology could be combined with ultrafiltration separation technology to form a combined wastewater treatment process,which was suitable for the wastewater of MDF industry with high content of organic pollutants.The test results showed that the kinds of organic substance in the effluent after the combined treatment was about 70%lower than that of the origional water simple,and the removal rate of the alcohol,ketone,aldehyde and carbohydrate in the wastewater was 100%,the removal rate of phenol,ester and acid pollutants was up to 90%,and COD,SS,NH3-N and Chroma could be reduced more than 98%.The water from the exit could meet the national water quality standards(GJ/T48-1999)and could be reused for production,with pH 7.0?7.8,COD<50,SS<10,NH3-N<10 and Choma<20.(4)During the Fenton-Ultrafiltration combination process,the ultrafiltration membrane would be covered with contaminants,making the membrane flux dropped significantly.The cleaning method with 0.5%citric acid + 1%sodium hypochlorite + ultrasonic vibration could effectively remove the contaminants adhered to the membrane surface and membrane holes,and the membrane recovery rate reached 350%after cleaning.(5)With the Fenton-Ultrafiltration combination process,The treatment costs of MDF wastewater was 2.356 yuan per ton.Compaired with traditional wastewater treating technology of MDF industry,the Fenton-Ultrafiltration combination process studied in this paper showed lots of advantages,such as strong decontamination ability,good treatment effect,low construction investment,small land occupation,high degree of automation,easy operation and low running cost,and could be expected to find its use in practical production. |
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