What is an in-situ methods to remediate a plume of chlorinated solvent contaminated groundwater in sandy soils? (process, different streams, disposal of byproducts, reagents used, equipment used, permit requirements, cost comparison, and factors that affect the selection process.)© BrainMass Inc. brainmass.com October 3, 2022, 1:48 am ad1c9bdddf
SOLUTION This solution is FREE courtesy of BrainMass!
There are basically two methods of in-situ treatment of chlorinated solvent in groundwater: physical/chemical treatment methods, or biological methods. In situ solidification/stabilization detoxifies contaminants in the sediment by separating them from the environment, or by changing them into a chemically-unavailable form. Air sparging, directional wells, dual phase extraction, and fluid/vapor extraction are separation techniques. They are generally effective and relatively fast, compared to bioremediation. However, physical methods are generally not used to treat organics due to their tendency to become more unstable degrade, so would not be appropriate in this situation.
Biological methods, or bioredmiation, have become increasingly popular as science improves our understanding of the process. A number of microorganisms use chlorinated solvents as electron receptors, effectively rendering them harmless. The use of these bacteria has a number of benefits: it's cost-effective and causes limited disturbance of the environment. Passive bioremedation implies a simple injection of biological agents into the contaminated area. Active bioredmediation involves a means of recycling the biological agent back into the ground. This can greatly increase the expense of the operation.
One disadvantage of bioremediation is the high biological oxygen demand (BOD) seen in most sediments can limit biological or chemical treatment (Bokuniewicz et al, 1997). Few states have permit requirements pertaining specifically to the injection of bacteria into the subsurface. The specific type of permit required is largely dependent on the type of project undertaken, but all would require some sort of Underground Injection Control (UIC) permit.
Bokuniewicz, Henry J., et al. 1997. Contaminated Sediments in Ports and Waterways - Cleanup Strategies and Technologies. National Research Council prepared by Committee on Contaminated Marine Sediments, National Academy Press, Washington, D.C.