Study On Treatment Of Machining Cutting Fluid Wastewater With Macroporous Resin Andbiological Fixed Bed

Cutting fluid is a kind of oil(or liquid) used in machining process,it was used for cooling,lubricating,cleaning,antirusting and so on. Currently, most domestic machinery industry uses emulsified oil as metal cutting fluid. The mainly harmful components of metal cutting waste are mineral oil and chemical additives like surfactant,the most widely used treatment is the flocculation method combines with biochemical process both at home and abroad. The practice has proved that there are some drawbacks of the currently widely use of inorganic and organic flocculants, such as the treatment effect is not ideal, there exists secondary pollution to the environment, the residue has " carcinogenic,teratogenic,mutagenic" effects. Therefore, we consider to omit the flocculation process during the process of cutting liquid waste treatment, use the biological contact oxidation method to treat waste water directly.The COD concentration of the original metal cutting fluid used in the experiment is about 1.40×105mg/L. The waste water is milky white, a small amount of gray and black oil slick floating on the surface, its emulsified state is stable. We dilute original cutting fluid with sewage which COD concentration is 2.00×102mg/L. Then use single-stage biological contact oxidation unit to treat the dilution,determine the upper limit of COD concentration of cutting fluid wastewater that treated by biological contact oxidation method is no more than 1.00×104mg/L,and the best COD concentration of incoming water is 6.00×103mg/L, the optimum pH is 8; then we use four-stage biological contact oxidation units to treat cutting fluid waste which COD concentration is 6.00×103mg/L,determine the best HRT as 4d, the optimum concentration of DO as 4mg/L; wastewater treatment in conditions of the COD concentration is 6.00×103mg/L, HRT is 4d, DO concentration is 4mg/L, pH is 8, the result shows that in the case of test conditions are at their best, the COD removal percentage of the dilution processing system can reach more than 96%, SS is almost undetectable after the treatment. We infrare spectroscopy on both the incoming water and treated water, the result shows that almost all the oils in waste water are removed, the composition of the treated water is close to common water.The biological phase analysis of activated sludge in the treatment system shows that sludge contains a large number of ciliates and vorticellas,microorganisms active vigorously.According to the experimental parameters,we give an engineering design of a cutting fluid waste treatment project which treatment scale is 1m3/h.