DEZORB-IT is applied to the subsurface through permanently installed injection wells or direct push injection.
DEZORB-IT is a proprietary rhamnolipid/synthetic blend biosurfactant utilized to address petroleum hydrocarbons that are trapped (i.e. free product) and/or sorbed to smear-zone and vadose-zone soils. DEZORB-IT is manufactured by blending a non-ionic surfactant with natural rhamnolipids that are produced using bacterial cultures. Because the surfactant is non-ionic, it has no ionic constituents or groupings, and is part of the largest single group of surface-active agents. This allows the surfactant to a have a wide range of chemical characteristics and applications (ex. In situ surfactant flushing, in situ surfactant-enhanced bioremediation, pump and treat (i.e. DPE, MPE, etc.) system enhancement, in situ surfactant-enhanced chemical oxidation). The rhamnolipids blended with the non-ionic surfactant have been purified from Pseudomonas aeruginosa and contain a mixture of rhamnolipids with fatty acids of varying tail lengths. These rhamnolipids are highly biodegradable and non-toxic and will provide good detergency/foaming/wetting, stable microemulsion formations, and are soluble under high alkalinity conditions. The surfactant and emulsion properties of the rhamnolipid biosurfactant blend will include reducing the surface tension of the water to 25 to 40 millinewtons per meter (mN/m), having a critical micelle concentration (CMC) of 5 to 380 milligrams per liter (mg/L), and decreasing the interfacial tension of oil and water to <1 dyne per centimeter (dyne/cm). DEZORB-IT is easily biodegradable with a very low toxicity because of its higher EC50 values, it’s effectiveness is not affected by temperature, pH, or salinity, and it is highly sustainable.
How it works
DEZORB-IT is applied to the subsurface through permanently installed injection wells or direct push injection or applied to the ground surface to percolate through the unsaturated zone soils. When using the product for enhanced bioremediation or one of the other applications mentioned previously, it is highly recommended that groundwater is recovered from nearby monitoring wells to create hydraulic gradients to ensure contact is made throughout the impacted areas. Emphasis on balancing the volume of groundwater extracted and injected will maximize the effectiveness of the product. However, this product can just be injected without groundwater recirculation.
Volumetric calculations should be utilized to determine the mass applied at a project. Mass balance is not an appropriate measure of surfactant volume. A pore volume approach is the recommended method to determine the amount of surfactant used in a specified area. The focus should be on contact with as much pore space as possible in the treated area. Distribution methodologies in the focus area will be key to success of the product as physical properties such as lithology, transmissivity, and hydraulic gradient, either natural or induced, influence the distribution.
Varying surfactant concentrations are recommended for use with different remedial implementations. Enhanced bioremediation is recommended to have less than 1% surfactant solution (less than 1 gallon per 100 gallons injected). Surfactant flushing is recommended to have surfactant percentages ranging from 3% to 10%, with lower percentages used with lighter fuels (gasoline) and higher percentages used with heavier fuels (crude oil). When surfactant is used as an enhancement for dual phase extraction or multiphase extraction, a 1% to 3% solution is recommended with the surfactant pulsed into the system, not continuously injected.