Research On Treatment Of Machining Cutting Fluid Wsatwater

Machining cutting fluid wastewater has such characteristics as high COD,complicated ingredients and non biodegradable. It has become a real problem inwater treatment. In recent years, cutting fluid wastewater emissions have beenincreased and it become more difficult of the treatment of this kind of water, theenvironmental pollution is getting worse. So finding a feasible method to treatcutting fluid wastewater is very important and emergency. UV-Fenton system hasstrong oxidizing property and wide application range. It has been widely used andstudied in high concentration wastewater treatment. This paper mainly discussedusing UV-Fenton system as the main method to deal with different kinds of cuttingfluid wastewater and optimized the experimental conditions.Using Coagulation-UV-Fenton system to deal with cutting fluid wastewater,the most optimum conditions of the coagulation process were: initial pH was6.6;the dosage of PAC was7g/L, the dosage of PAM （mass fraction0.1%） was1.5mL/L; After the coagulation process, the removal ratio of COD was more than70%.Using different kind of technology to deal with the water after the coagulationprocess, we found that UV-FeSO₄-H₂O₂> UV-H₂O₂> FeSO₄-H₂O₂. Setting thereaction time to3h, the results showed that the most optimum conditions were:initial pH was3; the dosage of hydrogen peroxide was2.2mol/L, the way to addhydrogen peroxide was steady adding; the dosage of ferrous sulphate was10.79mmol/L. Then the COD of the water after UV-Fenton system was about3000mg/L, and its biodeqradability was good and meet the requirements of biochemicaltreatment. If the wastewater factory does not have the biochemical treatmentfacilities, it should be thoroughly degradated and then to be discharged.Let thewater be thoroughly degradated, the results showed that: the other conditionsremain unchanged, the dosage of hydrogen peroxide was3.3mol/L, and when thereaction time was5h, the removal ratio of COD relative to intake water can bereached98.06%, relative to raw water can be reached99.40%, and the COD was361mg/L, meet theⅡ-class criteria of Integrated Wastewater Discharge Standard（GB8978-1996）.In the UV-Fenton process, we found that the ammonia nitrogen value of thewater is very high, so we used ammonia stripping method to deal with the water.The most optimum conditions of ammonia stripping method were: pH was11; thetemperature of stripping was65℃; time of stripping was1.5h.After the strippingsystem, the removal ratio of the ammonia nitrogen can be reached95.22%. Using Acid-UV-Fenton system to deal with the other kind of cutting fluidwastewater. The result of the acid out experiment showed that the best pH of acidout was3. The most optimum conditions of UV-Fenton system were: the initial pHwas2.5; the dosage of ferrous sulphate was1.1g/L, the dosage of hydrogenperoxide was1.1mol/L, the way to add hydrogen peroxide was steady adding.Depending on the above optimal single factor conditions, we had some verificationexperiment. The result showed it has good reproducibility and the COD of the waterwas205mg/L, meet the Ⅱ-class criteria of Integrated Wastewater DischargeStandard （GB8978-1996）.