The Laboratory Tests About Oily Wastewater Useing Loess Soil To Treat

Loess in Lanzhou and the wastewater from a chemical factory in XiGu was selectedas research objects, basing on the chemical composition and physical propertiesanalyzing of the soil sample and water sample, Laboratory experiments of theoily wastewater treatment by theloess. Wass tudiedFirstly, by studying the adsorption capacity of loess for mineral oils,the adsorptionmode of the loess for the oily wastewater pollutants was identified and the influence oftemperature, pHvalues, and organic matter contents sand salt contents on the adsorptionwere investigated by laboratory static experiments. Then, the indigenous bacteria inloess were activated to reduce oil by supplementing nutrients and changing otherecological conditions to study the treatment effect of oil pollutant to oily wastewater inthe Loess. The influencing factors such as nutrient substance, temperature, oxidizer andpH were researched, and the optimal ecological condition was determined throughorthogonal experiment.Finally, the use of dynamic experiments to simulate the effect ofloess under dynamic conditions ofoily waste water treatment.The treatment effect of petroleum degradation bacteria on oily wastewater wasdetermined and the experiment provides theoretical basis for the feasibility that loess isutilized to treat oily wastewater. The following conclusions were draw through sortingout and analyzing the test results:（1） The static adsorption experiments indicate that Malan loess in Lanzhou region ofoily waste water treatment effect is quite good. Through the static adsorption of malanloess experiments can be concluded that the unit of oily wastewater in loess oil naturaladsorption quantity can reach1086.07mg/kg, The adsorption of oils on loess conformsto Langmuir isotherm;（2） The influencing factors experiments indicate that the adsorptive capacity dropsfrom1020.49mg/kg to1104.51mg/kg with the temperature elevating from20℃to45℃process; with the pH value elevating from13to3, the adsorptive capacity drops from1178.28mg/kg to998.95mg/kg; Adsorption tends to increase with the decrease ofdiameter of soil particles; There is a positive linear correlation between the adsorptionand the organic matter content or salt contents. With the organic matter content and saltcontent increasing, the adsorption increase.（3） The loess simulation experiments indicate that the loess-microorganismsystem has buffer effect and self adjusting function; adequate nutrients andantioxidants can improve the microbial loess processing efficiency; the best ecological conditions of Loess are as follows: nutrient proportion （C:N:P） is500:6:1, temperature is30℃, the accumulation dosage of H₂O₂is13mg/L, and pHis7.（4） The use of Malan loess to treat oily wastewater had a certain effect showed inthe dynamic experiments.（5） In the dynamic experiments, the surface Malan loess had a better treatmenteffect for the oily waste water, which indicated that petroleum-degrading bacteriain the Malan loess was mostly aerobic microorganisms, and contained a small partof the anaerobic microorganisms.