ARCHIVED REPORTS XR0001496 - Laserfiche WebLink

Home Browse Search

i microbial activity was such that we felt that, with the addition of the horse manure compost, a sufficient rate of detoxification could be achieved and eventual breakdown of diesel material would be obtained For some time, there has been knowledge that many common soil bacteria possess the ability to metabolically shift to take advantage of fuel hydrocarbons as food when encountered in soil Frequently, the bacteria involved include many different species of r pseudomonas Some more recent work has indicated the probability that many types of fungi are extremely active in the bio-degradation process and may actually present dominant roles in mineralizing fuel hydrocarbons There was no attempt made in this investigation to determine what the particular strains of microorganisms were. Although many organisms have been identified as active in the degradation of petroleum hydrocarbons, most of them are known as opportunistic utilizers. The opportunistic utilizer is sunply an organism which is able to use more than one type of food and has the aWity to shift its diet to whatever food source is most prevalent, 1'e, a carbon source. In this case, the organisms of interest were those adapted to utilizing petroleum hydrocarbons as a primary food (carbon) source. In some situations, an , inoculum may prove to be beneficial; however, the addition of a foreign source of 4u organisms may:irilnivit the rate of degradation by promoting competition for resources witht the native or indigenous population." Thein could also be a public relations problems associated with using an additional inoculums or microorganism in the soil, as there may be A fear that this added microorganism might be uncontrollable. In most cases, the native population and character of microorganisms is sufficient using the bioremediation method under discussion. In the case under discussion, no exotic inoculum or preparation was involved. The native soil was found to contain a sufficient population of the desired microorganisms. Thus bioremediation process operates by accelerating a naturally occurring process which is always taking place in the soil, however, if the natural process were allowed to continue unaided, many years would be required to break down the diesel. Alteration of the soil environment is necessary to provide the conditions necessary for the maximum mineralization of the contaminants. We found that the soil to be treated was literally loaded with microorganisms. The crux of successful bioremediation is to promote the welfare of the mixed inhabitants of the soil, the microorganisms present m the ecosystem as a whole. Providing an ideal growth environment produces the rapid-rate bio- degradation necessary to economically remediate diesel-contaminated soil This particular operation utilized the organisms in the soil which exist in a natural state of equilibrium. This equilibrium hinges upon the presence of different food sources, the availability of nutrients, the presence of oxygen and moisture, and other factors Certain of these factors are always in short supply, thereby,keeping a check on the populations of the microorganisms. We enhanced the utilization of the organisms by aligning the eating habits of the microorganism populations to include fuel hydrocarbons and by using the horse manure compost additive as a supporting nutrient In so doing, limiting factors •