The practice of adding a carbon substrate to the subsurface is an attempt to bring into balance electron donors and electron acceptors within a system. Since the carbon substrate acts as an electron donor  more...

The practice of adding a carbon substrate to the subsurface is an attempt to bring into balance electron donors and electron acceptors within a system. Since the carbon substrate acts as an electron donor, any electron acceptor identified as a “contaminant” can usually be treated with this method.

As an example, if oxygen were considered a contaminant at a site, adding a carbon source would provide the indigenous microbial populations an electron donor which can be metabolized using the oxygen as an electron acceptor. The same can be said for any materials or “contaminants” that can be used as an electron acceptor.

This leaves open a wide range of materials that can theoretically be metabolized, and therefore “remediated” by adding a carbon substrate to a system. To move down the oxidation-reduction potential (ORP) “ladder”, the most common electron acceptors are oxygen, nitrate, iron, manganese, and sulfate. less...

The metabolism of chlorinated solvents, most notably the chloroethenes, chloroethanes, and the chloroebenzenes degrade through the process of halorspiration or reductive  more...

The metabolism of chlorinated solvents, most notably the chloroethenes, chloroethanes, and the chloroebenzenes degrade through the process of halorspiration or reductive dechlorination with the substrate being fermented to produce hydrogen. Halorespiration can also be an important mechanism for contaminants such as chlorinated pesticides and herbicides. less...

The process of biologically treating metals uses the differences in solubilities of each metal under various oxidative states. Iron is typically insoluble under aerobic conditions but becomes soluble under reducing conditions.  more...

The process of biologically treating metals uses the differences in solubilities of each metal under various oxidative states. Iron is typically insoluble under aerobic conditions but becomes soluble under reducing conditions. A system can be further driven anaerobic producing sulfides that can react with the metals forming insoluble or less soluble metal sulfides.

The following is a short list of contaminants that can be bioremediated through the introduction of a carbon substrate:

Perchloroethene;
Trichloroethene;
Dichlorethene;
Vinyl Chloride;
1,1,1-Trichlorethane;
1,2-Dichloroethane;
Carbon tetrachloride;
Chloroform;
Chlorobenzenes;
Chlorinated pesticides (e.g., chlordane), polychlorinated biphenyls (PCBs), and chlorinated cyclic hydrocarbons (e.g., pentachlorophenol);
oxidizers such as perchlorate and chlorate;
explosive and ordnance compounds;
dissolved metals (e.g., hexavalent chromium); and nitrate and sulfate*.

*Principles and Practices of Enhanced Anaerobic Bioremediation of Chlorinated Solvents, Air Force Center for Environmental Excellence, Brooks City-Base, Texas and Naval Facilities Engineering Service Center, Port Hueneme, California, August 2004, AFCEE, Contract F41624-00-D-8024 and NFESC, Contract N47408-98-D-7527.

Information on the potential to degrade various materials either aerobically or anaerobically through biological means can be found in the Handbook of Environmental Degradation Rates (Phillip Howard, et. al., Heather Taub Printup Editor, Lewis Publishers, 1991).

JRW provides information regarding our products as a service to our clients. JRW is not a consultant and does not provide professional services. Every site is unique and care must be excercised by the practitioner to fully understand their own circumstances. less...