For successful remediation of hydrocarbons (in an aerobic environment), three things are needed at a given site; Intrinsic bacteria capable of metabolizing the carbon (contaminant); available and sufficient nutrient source (macro and micro nutrients) and adequate, usable oxygen. BRT focuses on these three main areas, determines what is lacking, then we manipulate these factors to achieve efficient bioremediation of the contaminants.
Dissolved oxygen (DO) is the most thermodynamically favored electron acceptor used in the biodegradation of fuel hydrocarbons. Biodegradation of hydrocarbons typically require 3.5 pounds of oxygen per pound of contaminant. Oxygen is considered by many to be the primary growth-limiting factor for hydrocarbon degrading bacteria, and it is normally depleted in zones that have been contaminated with hydrocarbons.
As a result, BRT designs and manufactures oxygen systems to spur the natural occurring bacteria. BRT’s Biological Oxygen Supply System (BOSS) is the main technique used for oxygen addition. The BOSS forces oxygen into water at a rate >45 mg/L. Leading to far greater usable oxygen than other technologies like sparging, chemical oxidation and aeration techniques. The technology behind the oxygen dissolution using the BOSS ensures that it will not come out of solution once injected into the subsurface. Once in the subsurface, the oxygenated water will follow the same pathways as the contaminants leading to greater and more efficient distribution. Lastly, the oxygenated water acts as a delivery mechanism for the site specific nutrients BRT formulates. There are multiple options for on-site applications.
The most efficient and cost effective BOSS is a semi-permanent system. This system can be retrofitted to fit any size site or remedial approach. The unit can be installed to fit an existing remediation shed / trailer or be housed in a stand-alone trailer. This option comes equipped with 24-hour telemetry so real time data can be analyzed from BRT offices. Multiple injection points, along with flows, can be manipulated without setting foot on site to ensure effective delivery to the treatment zone.
Another option for the BOSS is a mobile approach. The equipment is capable of being housed in a small pickup truck or van that can be easily transported. A water source can be used on site or potable water from off site can be brought in for sites with no infrastructure. Mobile applications use the same technology of the semi-permanent system except requires supervision while operating. Mobile injections are ideal for sites that have a little contaminant remaining to achieve attainment and doesn’t need a lot of money and infrastructure to meet remedial goals. Another positive feature of the mobile approach is that it can be utilized on multiple sites in a given month providing a cost savings to the client.
A standard site will see two injections per month with 1,000 gallons of oxygenated water, along with nutrients when applicable. BRT can perform these activities with our experienced field technicians or can lease BOSS units for clients to use at their discretion. The lease option allows for consultants / clients to utilize the BOSS at multiple site for the same one month leasing price.
All biological systems require a balanced blend of macro- and micro-nutrients as metabolic stimulants and growth enhancers, and can fail to produce the intended results if this nutritional ratio is improperly balanced. Thus, nutrient concentrations are a growth limiting factor. BRT specially formulates a nutrient blend of macro- and micro- elements to enhance the bioremediation process. The nutrient formula incorporates a specific ratio of elements to target a specific group of organisms that will enhance growth and increase hydrocarbon degradation at a given site. It is important to note that not all bacteria require the same nutrients nor can any one utilize all kinds. Thus, the proprietary, site specific, blend of nutrients are key for efficient degradation of contaminants.
Site specific nutrients are added on a monthly schedule. Nutrients can be injected in aqueous form (in conjunction with oxygen addition events) with proprietary nutrient concentrations less than drinking water standards. Nutrients will be injected through the same pathways as the oxygen.
Another option for nutrient addition is through BRT’s Smart Nutrient, a slow release, hydrophobic and oleophilic formulation. This allows for the nutrient compounds to be released when and where they are needed. Slow release enables the bacteria to have access to nutrients over a period of time and are desgined to target only the beneficial bacteria. Being hydrophobic and oleophilic ensures that the nutrient will not decompose in water and will activate when in contact with hydrocarbons. Smart nutrients are ideal for open cavities and tanks, soil excavations and soil piles.
BRT’s main focus is the isolation and development of the site’s native microbial population to treat soil, groundwater and other contaminated media. Without the natural occuring bacteria’s ability to adapt the contaminant of concern, BRT is unable to affect a site biologically, however, certain measures can be taken to enhance the biological population.
When a site is found to have low biological activity, BRT will develop culture consisting of a consortium of naturally occurring, site specific, contaminant-degrading bacteria for site injection. This “biological seeding” is used to increase the amount of beneficial bacteria found at the site. The microbial population of this biological seeding is greater than 1.0E+06 colony forming units (CFU) /mL.
BRT can develop aerobic or anaerobic bacteria for individual or multiple contaminants. This culture addition will enhance the biodegradation process by seeding the system with additional, indigenous, contaminant degraders. Indigenous microbes are desired for the following reasons:
Indigenous microbes are already adapted to a site’s unique chemical properties, conditions and concentrations, therefore survival rates of introduced culture (inoculum) is much higher than that of generic, non-indigenous culture.
Because no foreign organisms are used, there is less regulatory and/or public concern regarding the re-introduction of native organisms.