TRS offers the following two broad categories of contracting options for Electrical Resistance Heating (ERH) remediation:
Standard Fixed Price Remediation (SFPR) provides the lowest cost option, and Guaranteed Fixed Price Remediation (GFPR) is usually applied after a firm clean-up goal has been negotiated with regulators. Regardless of which method of contracting is used, TRS highly recommends checking references from previous projects. Details of each contracting option are provided below.
Standard Fixed Price Remediation
Using Standard Fixed Price Remediation contracting, TRS bills a fixed price for the completion of a set series of project tasks. Typically, these tasks are design, system installation and start-up, system operations, and demobilization and final reporting. SFPR is also the price basis for most of our preliminary budget estimates. For each remediation, TRS develops an estimate of the amount of electrical energy, in kilowatt-hours, that will be required to reach the remedial goal. This estimate is referred to as the “Design Remediation Energy.” The Design Remediation Energy is most strongly influenced by:
- The remediation volume (usually measured in cubic yards),
- The target VOC (boiling temperature and water solubility),
- The percentage VOC reduction desired (whether measured using soil samples or groundwater samples or both),
- The soil total organic carbon content (TOC), and
- The presence of low volatility hydrocarbons such as oil or grease.
Perhaps surprisingly, the Design Remediation Energy is relatively unaffected by the type of soil (gravel, clay or bedrock), the state of water saturation, the soil electrical conductivity, or the presence of DNAPL.
Under an SFPR contract, TRS will continue operation until the remedial goal is reached or until TRS has input the Design Remediation Energy, whichever occurs first. Based on previous experience, TRS estimates that about 85% of remediation projects reach the remedial goal prior to inputting the Design Remediation Energy. Under a SFPR contract, TRS is highly motivated to try to finish the remediation early. The client also wins because less electricity is used and fewer ancillary costs such as project management, sampling, and reporting costs accrue.
SFPR contracting protects the client from cost over-runs and change orders unless the original scope of work is increased. TRS charges no additional cost in the event its equipment malfunctions or if TRS is otherwise slow to complete its work due to factors within its control. For these reasons, change orders are very rare for TRS projects.
Guaranteed Fixed Price Remediation
GFPR contracting is usually most applicable when a specific numerical clean-up goal has already been negotiated with regulators. This goal is normally site-specific and has a risk-based component stipulating that no further remediation will be required upon achieving the goal for the site.
Because GFPR transfers risk from the property owner to TRS, these contracts result in higher project pricing. The exact amount of price increase over a SFPR contract depends on a myriad of site-specific details. However, the average price increase is about 15-20% of the total project cost. The guarantee is usually enforced by a large retainage (20-30%), which is payable only when the contracted clean-up goal is achieved.
In order to provide a GFPR, the parameters that impact the TRS Design Remediation Energy (bulleted items above) must be well-documented. Also, the performance measurement methods, the locations and the number of samples must be determined in advance. Either soil or groundwater samples can be used to measure guaranteed performance.
Regardless of how thorough the site assessment, there is always a possibility of undetected contamination just outside the treatment region along one of the remediation boundaries. To guard against possible flux of contamination into the treated region, TRS prefers that confirmatory soil samples be collected from locations that are at least 8 feet from a remedial boundary. Similarly, confirmatory groundwater samples should be collected from locations at least 15 feet from a remedial boundary, and perhaps farther in highly permeable soils or sites with high groundwater flow rates.
The price increase to provide a GFPR also depends on whether a statistical analysis is applied to data interpretation, especially if variable soil sampling is used to determine remediation success. The three principal data interpretation possibilities are:
- Sample average must be below the remedial goal - least difficult to achieve
- Sample upper confidence limit (UCL, e.g. 90% UCL) must be below the remedial goal - moderate difficulty
- All samples must be below the remedial goal – most difficult to achieve
For example, the following scenarios have similar difficulty:
- The average TCE concentration in soil must be less than 1 mg/kg.
- The 90% UCL TCE concentration in soil must be less than 2 mg/kg.
- All soil samples must have less than 20 mg/kg TCE.
If soil samples are used to determine if the remedial goal has been met, TRS will usually recommend several rounds of sampling. For example, the first round of soil sampling might indicate that 80% of the soil samples have VOC concentrations low enough to meet the remedial goal. TRS would then shut off 80% of the ERH system and concentrate efforts on the region that still requires remediation. The second round of soil sampling would include the 20% of locations that did not meet the goal in the first round and it is likely that all but one or two locations would pass in the second round. The third round of soil sampling might include just a boring or two.