Abstract: A method of killing microorganisms which form a biofilm on a tissue or implant surfaces in a patient, and which are refractory to a biocide at a dose which is effective to kill the microorganism in planktonic form. The effect of the biocide is potentiated, to an effective killing level, by applying an electric field across the surface containing the biofilm.

Abstract: A microbial system is provided for selective plugging of permeable regions of a subterranean formation, for use in conjunction with injection of surfactant-containing foams. Bacteria indigenous to the target formation are isolated, and selected for ability to degrade the surfactant of interest. Small, non-adherent ultramicrobacteria, or UMB, are prepared from the selected culture by starvation. The UMB and the surfactant-containing foam are then injected into the target formation. The surfactant allows the foam to penetrate into the formation. The UMB then revive to their vegetative state, degrade the surfactant and produce exopolymer, thus plugging the formation.

Abstract: A method is provided for removing biofilm from a surface submerged in water. The method includes cooling the biofilm to below the freezing point of water to thereby generate large, sharp-edged ice crystals in the biofilm. The frozen biofilm is then thawed and removed from the surface by, for instance, flowing a liquid across the surface.