How many sites have you remediated using this technology?
SMA has closed 11 sites using ERH.
What is the best application?
Remediation of volatile organics such as chlorinated solvents or petroleum products in low permeability soils (e.g. clay) where Soil Vapor Extraction will not work, and Dense Non-Aqueous Phase Liquid (DNAPL) below the water table.
What size project is appropriate for use of this technology and what are the costs?
If your site contains over 5,000 cubic yards of soil requiring remediation a reasonable estimate is $80 to $100 yd3, and less if the site is over 20,000 yd3. Due to the high costs of power control installation it is reasonable to assume a minimal cost of $300,000.
Will you do firm fixed-price remediations?
Yes, we will be happy to give you a firm quote as long as we have characterized the site or we have confidence in the characterization performed by others.
Is the technology applicable to remediation of sand?
Yes, if DNAPL needs to be remediated below the water table. If only sand above the water table is impacted SVE can probably perform the remediation at a lower cost.
When is the technology not applicable?
The technology does not work for the remediation of metals in soil and/or groundwater. It has limited application for the enhancement of remediation of PCBs and coal tars.
Can the electrodes be installed under concrete in an active workspace?
Yes.
Is building stability an issue if electrodes are installed in, or near, a building?
No. Surveys of buildings at numerous sites have shown that this is not a concern.
Is vapor recovery required?
It is dependent on Federal, State and/or local requirements. When vapor recovery is required we typically use activated carbon, but thermal destruction has also been used.
Is vapor migration inside a building a problem?
No. The treatment area must be covered (typically by asphalt or concrete). Vapors are removed by the vapor control system that operates under a vacuum. Typically, if there is a concern, indoor air quality can be monitored by use of SUMMA canisters.
How long does it take to complete the remediation?
Generally, approximately four months on a small project and a year for a large project though it is also dependent upon the remediation goals and the size of the impacted area.
How do you determine when remediation is complete?
Documentation of remediation goals (e,g, percent mass removal or maximum constituent concentrations) is done by confirmatory sampling. Initial confirmatory sampling is typically conducted after the design energy has been put in the subsurface, the mass evolution of the constituents of concern have dropped significantly and the subsurface temperatures are over about 80 degrees Celsius. Typically there may be a portion of the site that will require some small amount of additional heating.
What procedures are used to ensure safety?
Monitoring of stray current is conducted throughout the startup and the remediation. Security fences are provided to prevent unauthorized entry.