Biological Stacking Method Ectopic Repair High Concentration Of Petroleum Contaminated Soil Engineering Parameters

Taking saline-alkali soil of oil region in Dongying island as the research object, studied theengineering parameters of biopiling method, which was used to remend the soil contaminatedhigh concentration of petroleum by heterotopic. First, the basic physicochemical properties ofsaline-alkali soil based on island area of Dongying were analyzed, and made up highconcentration of oil-contaminated soil to simulate. Then, through single factor experiment,orthogonal experiments and simulated field experiments to reseach the influence of oilconcentration, temperature, soil moisture, organic matter contents, C/N and ventilationconditions for the capacity of efficient oil-degrading bacteria on the oil under laboratoryconditions. Finally, through dynamic monitoring the accuracy and feasibility of the projectparameters in simulated field experiments, and eventually, determined the optimumengineering parameters of biopiling method to degrade the soil contained high concentrationsof petroleum. Further more, provided data reference for the application of biopilingtechnology in the real field, and ultimately achieve large-scale application. The mainconclusions were as follows.Univariate results showed that:(1) The suited concentration of petroleum contaminated soil to use biopiling technologywas about2%. And the dgradation abilities of oil degrading bacteria were reduced with oilconcentration increased. When the concentration of oil was1%, the degradation rate was69.04%, and when the concentration of oil was2%, the degradation rate reached65.04%.Howerer, when the concentration of oil was more than4%, the degradation ability ofoil-degrading bacteria was weak, the degradation rate was only21.38%.(2) The optimal concentration of oil-degrading bacteria was5×109cfu/kg, while thedegradation rate was65.29%. In unvaccinated oil-degrading bacteria and microbial inoculumconcentration was1×109cfu/kg, the degradation rate of petroleum hydrocarbon in soil was33.51%and53.80%, respectively. However, when microbial inoculum at a concentration of1×1010cfu/kg, the degradation rate of petroleum hydrocarbon in soil didn’t rise but drop to44.63%.(3) The oil-degrading bacteria had stronger degradation capacity, when piled body’stemperature was25℃,35℃, the degradation rate of petroleum hydrocarbon were65.30%and65.91%, respectively. The activity of oil-degrading bacteria was inhibited,when thetemperature reached45℃, the degradation rate of petroleum hydrocarbon was only50.42%.(4) The degradation rate of oil-degrading bacteria on petroleum hydrocarbon reached 65.26%, the highest, when oil moisture content was60%. When soil moisture content were30%,40%and50%, the degradation rate of oil were54.13%,51.42%,52.50%, respectively,no great difference. But, the degradation rate decreased to50.34%when soil moisture contentraised to70%.(5) The degradation rate of oil-degrading bacteria was66.67%, the highest, when theaddition of straw was5%. While the addition of straw was zero,1%, and2%, the degradationrates of petroleum hydrocarbon were65.36%,65.47%, and65.91%, respectively.(6) The C/N ratio in soil was preferably10:1, the degradation rate could reach67.34%,which increased by about2.11percentage points, compared to adding no urea. Meanwhile,when the C/N ratio in soil was20:1, the degradation rate was65.77%.(7) The degradation rate of oil-degrading bacteria was the highest, reaching65.60%,when ventilation frequency was once every five days. Meanwhile, when ventilation frequency wasnever, per one day, every three days, and every seven days, the degradation rates of petroleumhydrocarbon were39.16%,65.36%,65.22%, and57.76%, respectively.The results of orthogonal optimization experiments showed that: when oil concentrationwas2%, microbial inoculum concentration was5×109cfu/kg, the temperature was set to25℃,soil water content was60%of field moisture capacity, organic matter content(cornstalks) was5%, soil C/N ratio was10:1, the ventilation frequency was every five days, the total time ofdegradation was lasting to40days, the biopiling method could achieve the most desirableoutcome. By setting the best engineering parameters all above, the degradation rate ofpetroleum hydrocarbon in pile body could reach68.65%.The results of simulated field test showed that: The best engineering parameters gotfrom orthogonal optimization experiments were more accurate. And the moisture content ofpile body reached to38g/kg in15th days, the maximum. When the number of days was in26,the frequency of water replenishing, two or three days was OK. After26days, the frequencyof water replenishing, every five days was OK. Futhermore, in practical engineeringapplication process, water replenishing of the pile body could be done in the ninth days, andreplenishment quantity of water shoule be controlled within125g/kg.