Bioventing Scale-up Factor

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Properties contaminated with petroleum hydrocarbons continue to get the attention of society and government agencies. One reason is the need to remediate these contaminated sites in order to mitigate possible adverse health issues. The other reason is the major cost liability to remediate all these sites, which globally ranges from US $12-$35 billion. Bioventing has the potential to be a cost effective remediation technology, provided the optimum nutrients and water are added to the soil to stimulate the native microbial population to degrade the petroleum hydrocarbons. Unfortunately, many of the laboratory studies completed to assess if biodegradation is feasible and to determine the associated degradation rate have been done with less than 500 g of soil. Furthermore, many of these studies are done on laboratory contaminated soil and not aged contamination from actual field sites, making it difficult to transfer the findings to the field site. Accordingly, biodegradation studies will be done using 100 kg reactors to obtain degradation rates and evaluate the scale-up factor. Parameters to be studied include aging of the contamination, oxygen consumption, amount of microbial growth, water content, pH and impact of soil properties. Soil heterogeneity is an important component and will be incorporated. The degradation rates obtained from the larger scale experiments will be used to refine the overall degradation correlation previously determined and compared with previously completed 4 kg studies to further develop the scale-up factor. The overall goal is to identify the important site characteristics needed in lab studies to establish the scale-up factor so that bioventing performance in the field can be better estimated. Doing so will provide a cost effective means of restoring petroleum contaminated sites in Canada and the world, providing many jobs. Work will also continue on converting an existing 3D SVE model to a bioventing model that will incorporate the developed degradation model and the scale-up factor. This model will give consultants a tool by which they can predict effectiveness of bioventing for a given site and estimate the time needed to attain closure, a question site owners and government officials continue to ask. The end result being, improved bioventing technology that will contribute to sustainability and create job opportunities.