Field tests and mathematical model study of bioremediation of oil-contaminated soil and water.

摘要

Two bioremediation field tests were conduced in this study. The first one is a bioremediation of a Bunker C oil contaminated soil in a fire-wall area. This fire-wall area was separated into 18 plots by dirt dikes to test 6 bioremediation methods with three triple tests of each method. The six treatment methods were: (1) Aeration with basic nutrients and indigenous organisms, (BNIO); (2) Aeration with basic nutrients and inoculation from a refinery wastewater treatment facility, (BNFINA); (3) Aeration with an oleophilic fertilizer and indigenous organisms, (INIPOL); (4) Aeration with basic nutrients and biosurfactant organisms (EPA Seal Beach consortia), (EPA); (5) Aeration with proprietary nutrients and organisms, (PRO); and (6) Aeration only for active control, (CONTROL). This field test was conducted for ninety-one days. In general the oil contents in 18 plots were reduced though the results showed significant fluctuations. A statistical method was used to examine if the oil reductions of six methods were the results from the random error of sampling and sample analysis or biodegradation. The results of the statistical analysis showed that oil reduction was concluded from all but the plots of PRO. A mathematical model was developed to describe this biodegradation processes. From the data analysis and the simulation results, it may be concluded that the oil reduction rate in these studies is controlled by oil transfer from soil into the aqueous solution. An example of calculation was used to illustrate this conclusion.; The second field test is a bioremediation of water in an open ditch which was contaminated by machine oil. Three compartments were built to test the effects of nutrient and nutrient/aeration. Field test results indicated the nutrient/aeration has a significant effect while nutrient only has no effect on the oil biodegradation rate. A mathematical modeling was developed to describe the field test data from compartment of nutrient/aeration.; A modified treatment system was suggested to enhance the oil transfer rate with soil tilling in an aqueous system. A new oxygen supply system instead of the old soaker hoses dispersion system was developed to make the operation of tilling easy. The mathematical model for this treatment system was developed and applied to EPA plot #12 (in the first field test). The model results indicate that the oil reduction rate in this bioremediation system can be controlled by the tilling frequency, the DO concentration at the outlet of the aeration tank, and the water pumping rate.