Dennis Owens
Sustainable Water Technology, Canada
Title: In-situ regeneration of carbon based injectants with endemic biofilms
Biography
Biography: Dennis Owens
Abstract
Background Statement: Activated carbon (AC) has long been used to remove organic impurities from liquids and air. Generally, in the environmental field, we store AC inside vessels and then pump groundwater or air, contaminated with volatile organics, through the carbon vessel. This process injects AC into the contaminated mass itself to remediate the contaminants in-situ. AC has an affinity for organic chemicals, such as petroleum hydrocarbons, and organic chemicals will physically bond (absorb) to the micropores of the AC through Van der Waals forces. Once the chemicals are adsorbed to the carbon’s surface, the process generally can be reversed only by heating the carbon to very high temperatures, by use of a solvent, or through microbial processes. AC has been found to remain stable under extreme environmental conditions for long periods of time. The purpose of this study is to evaluate methods to stimulate biofilm formation to regenerate in-situ AC.
Methodology: Laboratory contaminated soil columns are injected with AC and various additives to stimulate biofilm formation throughout the AC. Each different soil type was then evaluated for types of microorganisms forming the biofilm and their effectiveness in regenerating the AC.
Findings: Different soil types produced the same basic biofilms composed of the same four basic organisms predominating with various subcultures specific to the area and soil type. All biofilms could regenerate the AC in-situ.
Conclusion: Biofilms can be formed in-situ within the AC area and in the process of biofilm formation the AC is regenerated for continuous remediation in-situ. Cost implications are significant for this remedial tool.