Aerobic cometabolism of TCE may be limited by the potential microbial toxicity of by products or by product metabolic repression. An independent comparison of induced cometabolism using soluble methane and CL-Out bioaugmentation showed that CL-Out bioaugmentation removed more TCE. The TCE removal rate by CL-Out when supplemented with an oxygen source was a steady rate that continued past apparent limits of induced cometabolism. The significant difference may be in that the population of beneficial microbes that can be added is much higher than the population level that may be achieved through biostimulation. For a brief summary of the study follow this link Overcoming TCE Metabolic Limits.
When a source of ground water contamination or contaminant vapors is present under a building, efforts to mitigate the spread of contamination may continue indefinitely with mounting costs. Bioremediation may be used to remove the source of vapors or ground water contamination without damage to the building or interrupting operations.
There are many examples of this approach in the case studies on this site. You can call us to find whether this approach is applicable to your site and the potential cost savings.
Petrox bioremediation of surface spills and TPH accumulation in drainage ditches and maintenance areas is simple. Using a simple manual sprayer, the Petrox is applied to the soil surface. The Petrox microbes begin bioremediation immediately to enhance natural digestion of the petroleum, like probiotics for petroleum destruction. Unlike detergents that was the visible oil away, Petrox microbes destroy the all of the oil.
The following chart and table show the results of the application of Petrox to petroleum-contaminated soil in a drainage ditch. After about 60 days, the TPH concentration was reduced by 67% in one location and over 90% in three locations. A second application to the 30 ft. north area reduced the concentration even more.
The problem was solved for a total Petrox cost of $600.
Petrox EC is a product that combines a surfactant with petroleum-degrading microbes to improve separate phase oil recovery and bioremediation of residual oil. The combined approach improves the rate of oil removal from soil and other subsurface media and establishes a beneficial petroleum-degrading microbial population that will treat tightly bound or deeply penetrated oil.
Petrox EC has been used in combination with periodic LNAPL extraction by pumping or bailing. In field applications the surfactant effect has increased the LNAPL recovery rate by more than 10 fold.
Petrox EC has also been used to improve the efficiency of air sparging by flushing oil from the sediment surface for sparging and vapor phase recovery.
Cometabolism is considered the indirect beneficial destruction of a contaminant compound by a microorganism that is growing on another substrate. While the benefit may be fortuitous, cometabolism can be directed and controlled to improve the environmental benefit.
CL Solutions has used cometabolism in three ways for bioremediation of different types of compounds.
• CL-Out® is a consortium of microbes that cometabolize chlorinated solvents under aerobic to anoxic conditions. The microbes metabolize dextrose as a primary substrate and constituatively produce dioxygenase enzymes that convert PCE, TCE and other chlorinated aliphatic compounds into organic acids that are metabolized.
• CL-Out® has been used to remove perchlorate from soil and ground water while growing on a substrate and using perchlorate for respiration. The substrate provides a carbon source and the perchlorate reduced by respiration. This approach can also be used for denitrification.
• In a novel approach, a simple sugar can be used as a substrate to support microbial growth when the concentrations of the target contaminant are too low to support an effective population density. This approach was used for pesticide bioremediation when the ground water concentrations were less than 0.1 µg/L and the remediation goal was 0.002 µg/L.