Low Cost In Situ Technique for Mercury RemovalEPA Contract Number: 68D00235
Title: Low Cost In Situ Technique for Mercury Removal
Investigators: Rainer, Norman B.
Small Business: Dynaphore Inc.
EPA Contact: Manager, SBIR Program
Project Period: September 1, 2000 through March 1, 2001
Project Amount: $64,500
RFA: Small Business Innovation Research (SBIR) - Phase I (2000) RFA Text | Recipients Lists
Research Category: SBIR - Waste , Hazardous Waste/Remediation , Small Business Innovation Research (SBIR)
Description:Techniques earlier employed for the removal of trace levels of mercury from water have included: (1) the use of a precipitating agent and associated filtration step, (2) immobilization treatments wherein precipitating agents are merely applied to soil or groundwater, (3) ion-exchange technology, (4) selective absorbents, (5) membrane separation processes, and (6) electrolytic methods. Each technique has certain shortcomings, and none are amenable to in situ or passive remediations.
The FORAGER? sponge was developed in 1992 as a result of studies directed toward finding a chelation-type selective ion-exchange material, which can be deployed in an absorption bed having little impedance to water flow. In one embodiment, the sponge consists of ?-inch cubes of an open-celled cellulosic sponge impregnated with a polymer having amine and iminodiacetic acid groups. The cubes are confined easily within fishnet-type tubular enclosures that can be emplaced to treat gravity-flow water in passive or in situ installations for the remediation of groundwater, stormwater, landfill leachate, and industrial discharges.
The effectiveness of the sponge in selectively removing trace heavy metals such as Pb, Cd, and Cu from groundwater was proved in a Superfund evaluation conducted in 1994 (EPA/540/R-94/522). In other tests, conducted on EPA-submitted samples of groundwater, the sponge reduced mercury from 40 ppb to nondetect levels in gravity flow columns, but contact times of 10 minutes were required.
Currently, the sponge is being manufactured in a pilot plant operation by Dynaphore, Inc., in Richmond, VA. A Web site (www.dynaphore.com) provides an overview of targeted areas of use. The limited sales thus far achieved are accounted for primarily by nonpoint source polluters who either cannot afford or cannot justify the capital expense required for traditional remediation techniques.
Recent research at Dynaphore, Inc., has provided insight into mechanisms for altering the functionality of the polymer. The Phase I objective is to optimize the functionality for mercury absorption with emphasis on improved kinetics. The research methodology would initially involve column absorption studies using the polymer in granular form, thereby measuring the length of absorption bands produced at a standard flow rate. Sponge products will be produced from the optimized polymer and studied in columns of 8 to 12 inches I.D. to correlate efficiency of mercury removal versus residence time and impedance to flow.