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FAQ
Q. How do I engage the services of GBI? A. Go to our Confidential Contact section. Fill out the form and describe in detail your technical problem or concern. A GBI representative will reply quickly with his/her recommending action. Q. For the remediation application, do you find butane-utilizers in most soil and groundwater conditions? A. Butane-utilizers do seem to be ubiquitous. However, a simple laboratory bench-scale test can be conducted to confirm or deny the presence of butane-utilizing organisms in a soil or groundwater sample. Q. Can the Butane Bioventing™ and Butane Biosparging™ technologies be applied concurrently at a Site to remediate contaminated soil and groundwater and to control contaminant fugitive emissions? A. Most definitely. The technologies were developed to operate concurrently at a Site and to expand butane biotreatment from the groundwater to the soil. Q. Does GBI sell butane injection equipment? A. No. GBI provides the Butane Injector 2000™ for a specified time at a given project under a technology use agreement. Q. How is butane used to degrade pollution in soil and groundwater? A. Bioremediation has historically been shown to be an effective in-situ remedial method. The availability of oxygen as well as the low cell densities of indigenous microbial populations limits the process of natural attenuation. Enhancing the process of natural attenuation with an active bioremediation system accelerates contaminant destruction in a cost-efficient and timely manner. The patented Butane Biosparging™ and Butane Bioventing™ processes enhance and accelerate natural attenuation by inducing the naturally occurring bacterial populations to express the requisite enzymes that degrade a wide range of environmental pollutants including chlorinated solvents, BTEX and MTBE. Natural attenuation is enhanced with the addition of butane, an easily metabolized microbial food source, and oxygen, an electron acceptor. The contaminants are degraded through direct metabolism (petroleum hydrocarbons) or cometabolism (chlorinated compounds and MTBE) of the contamination under aerobic conditions. Contamination is degraded directly to carbon dioxide and water. No hazardous intermediate breakdown products are created. The greatest benefit with an in-situ technology is that no waste stream is produced that needs to be managed and treated. The Butane Bioventing™ system allows for vapor control while reducing the overall operation and maintenance costs by eliminating the need for carbon replacement or regeneration and by recycling the butane gas back into the butane biotreatment zone. This process is more efficient than other technologies that add only oxygen (an electron acceptor) because biodegradation is greatly increased when the natural microbial populations are also provided access to an easily metabolized food source (butane). Q. Does the process employ inoculation methods? A. No. Butane Biostimulation Technologies™ enhance natural attenuation processes. This approach relies on the ability of many different indigenous bacteria to cooxidize chlorinated solvents, BTEX and MTBE, as well as a variety of other pollutants while growing at the expense of butane. Inoculation methods are difficult to implement at any site due to the problems related to mixing the foreign microbes into the subsurface in the area of a release and ensuring their survival once they are released into the environment. Butane Biostimulation Technologies™ are designed to enhance the growth of microbes that are already acclimated to site conditions. Q. How is the butane added to the subsurface? A. Oxygen is supplied to the subsurface through a series of injection wells connected to an air compressor. Butane gas is mixed with the airflow stream using a specially designed gas delivery system (Butane Injector 2000™) that can control the amount of butane gas added to the injection wells. The injection wells are installed with a drill rig and constructed with standard off-the-shelf PVC and steel piping. Q. Is butane toxic? A. Butane is considered a non-toxic substance. Butane is a general purpose food additive and is used in the food processing industry to extract vital oils and flavors from a variety of food sources. It is also used as an aerosol propellant for health care products that contact the skin. At very high concentrations (>10,000 ppm) it is an asphyxiant and may demonstrate narcotic effects. Concentrations generated in the subsurface with the butane injector are less than 0.01% of this concentration. Unlike other remedial technologies that require handling large quantities of dangerous oxidants, this technology uses a remedial additive that is safe to use and handle. Q. Is it possible for an explosive condition to be created in the subsurface when using butane? A. No. The Lower Explosive Limit for butane is greater than 10,000 ppm. After the butane gas is mixed with the air-flow stream supplied by the air compressor the butane gas is diluted to such an extent that concentrations generated in the subsurface with the butane injector are less than 0.01% of the LEL. In addition, the Butane Injector 2000™ is manufactured by the Whitmor Company / Omni-Trol Industries Inc., a firm specializing in custom engineering and design applications. The equipment is UL Listed, Coast Guard approved and complies with all federal, state and local laws and regulations pertaining to compressed gas storage and usage. The Butane Injector 2000™ is also equipped with a fire suppression system: the Fireboy Clean Agent FE241 Automatic Fire Extinguisher is designed to automatically discharge the agent FE241, chlorotetrafluoroethane, an Environmental Protection Agency approved alternate to Halon, when heat from a fire melts a lead wick on a discharge actuator at 175 degrees Fahrenheit. The butane system is safer that a barbeque grill or a home heating system (natural gas). Q. Can Butane Biostimulation Technologies™ be used as a barrier technology or for source area treatment? A. Yes. The number and placement of the injection wells is dependent on the areal and vertical extent of the contaminant plume, contaminant concentrations, and subsurface lithologies. The injection wells can be installed at any depth and have been used to control the migration of large contaminant plumes at a fraction of the costs associated with conventional barrier technologies. In addition, Butane Biostimulation Technologies™ have been used to treat the source area portions of much larger contaminant plumes. Q. Are any undesirable residuals left in the subsurface once the remediation project is complete? A. No. Butane Biostimulation Technologies™ stimulate the growth of naturally occurring microbes using butane as a food source and oxygen as an electron acceptor. Once the project is complete and butane is no longer being added to the subsurface the microbes are no longer being provided with an easily metabolized food source and their numbers decrease and return to their natural levels. Q. Is the operation and maintenance of the Butane Biostimulation Technologies™ treatment system labor intensive? A. One of the most attractive features of this technology is that the butane injection equipment has been engineered to be simple and effective. Once the equipment has been installed, the operation and maintenance of the system is related to replacing empty butane and nitrogen cylinders. In general, it takes approximately 15 minutes to replace a cylinder. At most sites O&M visits are usually scheduled monthly. This is unlike labor-intensive remedial additive technologies that involve handling large amounts of hazardous chemicals and adding them to the subsurface over numerous addition events. Q. What benefit does the butane technology have when being used to treat low permeability soils? A. Butane is the most soluble of the gaseous alkanes. It has more than four times the solubility of methane and twice that of propane. Butane is highly soluble in water. High solubility results in increased microbial access or bioavailability, which in turn results in high cell densities in both the soil and groundwater. The butane and air is mixed into the subsurface in the vapor phase using a series of injection points. The use of a vapor-phase remedial additive increases the ability of the butane and air to become a dissolved phase component of the groundwater and to become bioavailable to indigenous microbial populations. This process is more effective in low permeability soils than remedial technologies such as in-situ oxidation or bioaugmentation due to the difficulties in mixing a liquid into the saturated zone of an aquifer and ensuring that the remedial additive is able to migrate into areas of the subsurface where the contamination is located. Q. How long does the treatment process take? A. Butane Biostimulation Technologies™ enhance natural attenuation. The period of operation could range from 6 to 18 months, or longer, depending on the areal and vertical extent of contaminant plume, contaminant concentrations and subsurface lithologies. Remediation times of less than 4 months have also been documented using butane injection. Q. How much of a cost savings do the Butane Biostimulation Technologies™ provide? A. Butane Biosparging™ and Butane Bioventing™ technologies require minimal O&M and do not produce a waste stream. These technologies greatly shorten remediation time, are easy to manage, and reduce costs by up to 50% compared to conventional technologies (i.e. pump and treat, air sparging, soil vapor extraction with activated carbon, etc.) |
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