Modelling biofilm-induced formation damage and biocide treatment in subsurface geosystems.
Bottom Line: Persisters describe small subpopulation of cells which are tolerant to biocide treatment.Biofilm tolerance to biocide treatment is regulated by persister cells and includes 'innate' and 'biocide-induced' factors.Also, a successful application of biological permeability conformance treatment involving geologic layers with flow communication is more complicated than simply engineering the attachment of biofilm-forming cells at desired sites.
Affiliation: Department of Chemical and Petroleum Engineering, Schulich School of Engineering, University of Calgary, Calgary, Alberta, Canada. email@example.comShow MeSH
Related in: MedlinePlus
Mentions: As shown in Fig. 8, the nutrient front in a layered network exhibits a dominant finger after 0.19 h of simulated time. However, the whole network eventually becomes saturated with nutrient. Figure 8 shows nutrient concentration and biofilm occupancies for case L1 (i.e. biocide injection commencing after 2.5 h) while Fig. 8 shows results for case L2 (i.e. biocide injection commencing after 6 days). In cases L1 and L2, biofilm is seeded in both the top and bottom layers. The results show that the biofilm enlarges and clogs the upstream region of both layers, causing nutrient-limited growth in the downstream region of each layer. The effect is preferential growth towards the nutrient supply which increases bioclogging towards the inlet of each layer. Biofilm accumulation however occurs at a faster rate within the higher permeability bottom layer. Results here indicate that for conformance problems where the aim of the process is to reduce flow from the high permeability bottom layer (as may be desirable during waterflooding in oil fields or bioremediation by bioclogging to minimize the transport rate of underground contaminants), then permeability damage of the bottom layer will be considered an improvement in process productivity (i.e. water is channelled to the lower permeability layer). However, permeability damage of the top layer for such a case will represents a decline in productivity and can be described as formation damage.
Affiliation: Department of Chemical and Petroleum Engineering, Schulich School of Engineering, University of Calgary, Calgary, Alberta, Canada. firstname.lastname@example.org