Posts Tagged ‘Electrical Resistance Heating’

Small Site Electrical Resistance Heating BTEX/Chlorinated Solvents

May 8th, 2014

Small Site Electrical Resistance Heating

Small Site Electrical Resistance Heating Mobile Trailer

Small site contaminated with BTEX and/or chlorinated solvents


The purpose of this report is to discuss a new, and economically viable, clean-up solution for small sites contaminated with BTEX and/or chlorinated solvents.

GRS is offering a Small Sites version of electrical resistance heating (ERH) as a remediation option for small, persistently impacted sites in the Pacific Northwest.

Three Target ERH Applications

Recalcitrant Sites: Properties where a number of remediation technologies have been applied without achieving a pathway to site closure. Typically, soil matrix issues are causing contaminant rebound. Often, site owners would like to expedite clean-up to facilitate a property transfer.

New Sites with Tight Lithology: Smaller sites with tight glacial tills where clean-up activity has not started. These sites become ERH candidates when viewed on the basis of life cycle costs to achieving site closure. This is especially true for owners who want to shorten typical clean-up timelines and eliminate the risks of rebound Small Site Electrical Resistance Heating.

Source Area Treatment: Often, over 50% of on-site contaminant mass is found in small source areas. ERH can be used to effectively eliminate this mass while other technologies are deployed to treat the larger low-concentrating contaminant plume. Often, Small Site Electrical Resistance Heating can enhance the clean-up rate and effectiveness of other remediation technologies.

Proven Technology, Rapid Clean-Up, and No Rebound

A Proven Technology: ERH was developed by Battelle NW Laboratories and has been commercialized for about 15 years. ERH clients include: Department of Defense; US EPA; State Regulatory Agencies; Fortune 100 companies; and regional industries.

Over 200 ERH projects have been completed in North America with contaminant reductions typically reaching 99.9+%. The target market for ERH is large, highly contaminated, industrial, and Superfund Sites.

A New Approach: GRS is redefining ERH to address the requirements of small sites. We are building Power Delivery Systems designed and sized specifically for smaller clean-ups. Downsizing power delivery systems allows the entire ERH process to be scaled to smaller sites. At some sites, portable ERH systems ca n be plugged into existing facility power supply.

Timeline: Even using portable power delivery systems, small sites can be cleaned within 6 to 8 months with about 60-90 days of heating. Heating is sufficient to remove the contaminant sources responsible for rebound.

Rebound: Rebound is an issue for all in situ remediation technologies except ERH. Caused by the non-uniform dispersion of treatment throughout the soil matrix. Technologies that rely on the movement of oxidants, or air, through saturated glacial tills are particularly prone to rebound.

Alternatively, ERH relies only on the flow of electrical current to simultaneously clean soil and groundwater. Because current flow is not affected by soil type, ERH produces uniform performance throughout the treatment volume, eliminating the risk of rebound after heating.

Competitive Pricing for Small Site Electrical Resistance Heating

GRS recognizes that most small sites have limited funding for clean-up and often significant resources have already been spent on prior remediation efforts. Competitive pricing is a key component of our efforts to adapt ERH for the clean-up of small sites impacted with BTEX and chlorinated solvents.

GRS’ approach to pricing is based on reducing the costs under our control; spreading capital costs over multiple sites; and creating owner value through shortening remediation timelines and reducing risk.

  • Capital Cost: GRS power delivery systems are designed and built in-house, removing all markups.
  • Energy Efficiency: Advanced GRS designs are 10-15% more energy efficient than conventional ERH power delivery systems.
  • 480 volts: Where possible, GRS operates its small power systems at standard voltages to reduce the costs of power drops and electrical connections.
  • Mobile Systems: Housed in custom made 20-foot equipment trailers, GRS systems can be driven directly to Pacific Northwest project sites.
  • Local Support: The size and diversity of our Pacific Northwest resources gives GRS access to large pools of specialty equipment, skilled and flexible staffing, and shared overhead and administration costs.
  • Capital utilization: Provide clients who sign multiple site packages reductions on equipment rent as GRS allocates capital costs across the package sites.
  • Heat management: GRS deploys direct heating only for the period required to achieve the desired results in the heated zone and then re-uses that heat a second time for enhancing supplemental treatment such as bioremediation and ISCO.

Typical Small Site Costs

Costs for gas station and dry cleaner clean-ups involving impacted groundwater range from $400,000 to $800,000 with timelines of 4 – 10 years. Sites with the potential for significant rebound issues can consume these budgets and still fall well short of achieving No Further Action Letters.

GRS Small Site Electrical Resistance Heating Costs

GRS’ Small Site Program targets this same budget range, with remediation time frames of approximately 6 – 9 months and the elimination of the risk of rebound.

Pricing Quotes

Obtain free budget bids.

Michael Dodson


How does Electrical Resistance Heating Work?

April 1st, 2014


Electrical resistance heating is accomplished by passing an electrical current through the volume of subsurface soil requiring treatment. The process is equally effective in vadose and saturated zones. As the subsurface resists this flow of electricity, it is heated to the boiling point of the water/contaminant mixture present, regardless if the water source is soil moisture or a flowing aquifer. Following Dalton’s and Raoult’s laws, the temperature at which subsurface boiling occurs is dependent upon depth below the groundwater table, the type of contaminants present, and the ratio of contaminant concentrations. Increasing depth below the groundwater table and the presence of less volatile contaminants produces higher boiling points requiring increasing levels of energy consumption to reach remedial goals.


3-Phase ERH Diagram

The temperatures created by Electrical Resistance Heating-ERH is sufficient to evaporate targeted contaminants and produce an in situ steam source by boiling soil moisture and groundwater. This steam than strips contaminates from the soil matrix and carries them to vapor recovery (VR) wells that may be co- located with the electrodes.

ERH brings the subsurface to boiling in a smooth and controlled manner. Because Electrical Resistance Heating-ERH  needs soil moisture to remain above 5% to be successful, the technology cannot desiccate soil or cause subsidence. ERH electrodes do not become significantly hotter than surrounding soil and no excess energy is stored in the subsurface in the form of temperatures above boiling. If ERH application ceases for any reason, such as a site-wide power failure, steam generation in the subsurface stops quickly. For this reason, backup generators for vapor recovery and treatment systems are not a requirement for  Electrical Resistance Heating-ERH remediation projects.

Once heating at an ERH site starts, pure contaminants boil first, then groundwater with high levels of dissolved phase contaminants, and finally clean groundwater. Thus, ERH specifically targets the most impacted sections of the subsurface, including non-aqueous phase liquids (NAPLs) and contaminants adhering to the soil matrix. Additionally, ERH cleans saturated soil without having to dewater it, eliminating the need for groundwater extraction, treatment, and disposal systems.

Electrical Resistance Heating Contaminants

The type of contaminants and desired cleanup goals affect the energy, time, and cost to clean a given treatment volume. The two most important factors in evaluating the performance of ERH at a site are the level of total organic carbon (TOC) in soil and the presence of SVOCs such as heavy fuel hydrocarbons. Both of these substances hold CVOCs in the subsurface, making them more time consuming and expensive to remove regardless of the remediation technology deployed.

EPA-In Situ Technologies for Contaminated Soils

Dry Cleaner Remediation (ERH) – White Paper

July 9th, 2013

Electrical Resistance Heating  Small Site RemediationDry Cleaner Remediation

Electrical Resistance Heating (ERH) is an aggressive in situ remediation technology that can simultaneously remove chlorinated solvents from vadose and saturated soil. It can treat pools of dense nonaqueous phase liquids (DNAPL) found deep below the groundwater table and clean flowing aquifers. ERH systems have quickly cleaned acre sized source areas to depths of over 100-feet below grade. The technology is robust enough to return highly contaminated groundwater to drinking water quality.
Developed for US Department of Energy sites, a large ERH system applies high voltage utility-line power to electrodes placed in a grid pattern across an impacted site. As the subsurface resists this flow of electricity it is heated to the boiling point of water producing steam and contaminant vapors. These vapors are then collected just above the heated zone and treated.

Dry Cleaner Remediation

However, not all chlorinated hydrocarbon impacted properties are multi-acre Superfund sites. Many are former dry cleaner sites with small, but persistent, source areas.  They require Dry Cleaner Remediation.  Currently, no In Situ Thermal Remediation (ISTR) vendors configure their technologies specifically for the treatment of these dry cleaner remediation sites.

Global Remediation Solutions (GRS) is a national provider of ERH ISTR technology and services. We manufacture our own custom ERH equipment and can match it to any site configuration. We have developed a Small Sites Program specifically for the remediation of small chlorinated and fuel hydrocarbon source areas. Our program is based upon the following key concepts:

  • Competitive pricing based on a project life cycle costing.
  • Safe, green remediation technology providing no rebound.
  • Fast and complete remediation.  Clean-up goals met in months, with NFA letter 12 months later.
  • Mobile, customized compact ERH delivery systems requiring 440/480 electrical service.
  • Drilling and electrode designs and applications to maximize access, minimize cost, and provide full commercial use of properties during clean-up..

GRS would be happy to review any size project for the use of ERH for your Dry Cleaner Remediation.

ERH-Fast and complete chlorinated solvent clean-up.

June 15th, 2013

GRS Trailer 038 smallIn Situ Electrical Resistance Heating (ERH) is the most effective and efficient technology for the complete remediation of chlorinated solvents. Reaching clean-up goals in months, ERH addresses contaminated soil and groundwater with no rebound. ERH applications include both industrial and commercial sites, from large source areas to small dry cleaners.

Chlorinated solvents, such as PCE, TCE and their degradation products, persist in the subsurface because of their unique chemical and transport properties. After decades of operation, groundwater pump and systems have produced few, if any, site closures for these compounds. This leaves site owners with both persistently impaired property and on-going operation and maintenance costs.

ERH provides property owners a proven, fast, and complete remediation option that enables them to sell impacted property at full value or return it to productive use. The value produced by a quick and certain clean-up can be substantial for many properties.

GRS technical professionals can help you determine if ERH is a viable solution for your next remediation project. Because site conditions and contaminant parameters vary for every project, it’s best to start a dialogue early in the RI/FS process to determine if ERH is a fit for your site. We can also work with your staff to evaluate heat-enhanced bioremediation and heat-enhanced in situ chemical oxidization (ICSO).

Need a Quick Estimate? Have a site or project in mind with general details on the treatment volume, soil type, depth to groundwater, and contaminants of concern? Go to our quote formal request form and follow the easy to use bid request process.

Or contact:          Michael Dodson, , (360) 423-2245

All information provided through our bid request process will remain confidential. Project and site data are used only to perform a technology assessment and to develop accurate pricing.

To learn more about GRS and ERH, visit us our home page.

Global Remediation Solutions (GRS) is an environmental remediation technology company focused on the design and construction of in situ thermal remediation (ISTR) systems. GRS is part of the PNE Corporation family of companies. The size and diversity of the PNE companies, coupled with our highly respected environmental industry professionals, allows GRS to pursue major remediation projects on a national basis.

Electrical Resistance Heating (ERH) White Paper

June 9th, 2013

When chlorinated hydrocarbons, such as dry cleaning fluids and industrial solvents, are released into the environment, they migrate downward until they reach groundwater. Because they are heavier than water, they continue sinking through the aquifer until they find a layer of tight soil where they form pools of pure product. As these solvent pools slowly dissolve into the groundwater, they feed large contaminant plumes capable of impacting human health and the environment well down gradient of the impacted site.

These solvent pools are often found at depths of over 30-feet below ground surface and 20-feet below the water table, making them impossible to access using conventional remediation technologies. For example, the shoring and dewatering requirements for soil excavation and disposal at these depths represent insurmountable safety, engineering, and cost challenges. grs-3Phase-Diagram

Electrical Resistance Heating (ERH) is an aggressive in situ remediation technology that can simultaneously treat the solvents found in saturated and unsaturated soil, groundwater, and pools deep below the groundwater table. ERH is often used to clean sites where other technologies have had limited success. Using ERH, even large sites can be remediated quickly and completely. The technology is so robust that it can return highly contaminated groundwater to drinking water quality.

Developed for the US Department of Energy, ERH takes power from standard utility lines and applies it to electrodes placed in a grid pattern across an impacted site. As the subsurface resists this application of electricity it is heated to the boiling point of water producing steam and contaminant vapors. Installed to the maximum depth of contamination, ERH systems can heat to over 100-feet below grade.

During ERH, pools of solvents located below the water table are boiled first and this large contaminant mass is quickly removed from the subsurface. Next, steam formed in the subsurface starts driving contaminants out of soil and groundwater. As steam tries to escape from the subsurface, it sweeps contaminants to the recovery wells where they are collected and carried to the surface for treatment.
At the surface, steam and contaminant vapors are condensed into water, liquid contaminants, and cool contaminate vapors. Liquid contaminants are collected for recycling while condensate water and contaminant vapors are treated prior to release to the local sewer system and the atmosphere.

ERH can be applied in flowing gravel aquifers, heterogeneous glacial tills, and tight clays. It can treat fuel hydrocarbons, chlorinated solvents (dry cleaners), and polycyclic aromatic hydrocarbons (PAHs) such as creosote and coal tar. It can be safely used under roads, parking lots, and occupied buildings without disruption of traffic or occupancy. GRS would be happy to review any site for the use of ERH, and an easy to use site evaluation tool can be found on our web site.