Find Out How to Best Manage Your Site By Asking Yourself One Simple Question
The Industrial Revolution began over 250 years ago. In the Information Age the advantages and efficiencies of deploying equipment and automation to replace labour are affecting every facet of our lives, and at an ever increasing rate.
Most often the question is not whether a tool is available (it likely is); instead we seek to uncover the best tool for the job.
Subsurface contamination can be effectively managed using automated equipment to intercept and recover contaminant mass around the clock. These systems are designed to contain or shrink contaminant plumes, and prevent contaminants from reaching off-site or on-site receptors of concern.
But which type of system is best for the job?
Here’s the one question to ask when considering a treatment system:
“What is the physical nature and distribution of the contaminants we are attempting to remove from the subsurface?”
For example, are contaminants dissolved in groundwater only? If so, a pump and treat (P&T) system to contain a plume or dewater an excavation may be best.
If contaminants are volatile in nature and have not yet reached the water table, a soil vapour extraction (SVE) system should be considered.
But if contaminants exist in multiple forms, i.e. dissolved in the groundwater, as volatile compounds above the water table, and/or free phase product, it may be time to consider a multi-phase extraction (MPE) system.
Technologies can be layered to enhance deliverables to your client. For example, an effective dewatering and treatment system leads to efficient source area excavation. Or a strategically designed in-situ extraction system dramatically reduces contaminant mass to more readily achieve Risk Assessment goals.
Some sample projects to illustrate these concepts:
- Vertex recently completed a P&T project in Ottawa. A total volume of 1.75 million litres of water was recovered from an excavation over a 2 week period. An off-site disposal approach would have required dozens of vacuum trucks – an uneconomical and impractical alternative.
Therefore, the water was treated on-site to remove suspended solids and dissolved phase petroleum hydrocarbons prior to sewer discharge. The client realized savings of approximately $425,000 over the alternative solution.
- An SVE system has been operating at the facilities of an organic solvent and specialty chemical distributor since 2013. Vertex designed and installed the system to remove subsurface contaminant mass and to intercept the vapour plume, preventing off-site migration. From only five strategically placed extraction wells, a total of 1,500 kg of contaminant mass has been extracted from the subsurface and treated above ground via granular activated carbon.
- Vertex has been operating an MPE system in the GTA since 2009. The system was designed for the continuous removal of free phase petroleum hydrocarbons and to contain the dissolved phase plume, “pulling it back” from downgradient receptors. To date, in excess of 200,000 L of free product and 4 million litres of impacted groundwater have been recovered by this automated extraction system.
Properly designed SVE and MPE systems run continuously, 24/7, with very little on-going labour requirements for operation and maintenance. The result is uninterrupted operation of the impacted facilities while effectively addressing their environmental liabilities.
A note of caution: a permit is generally required to discharge treated groundwater directly to the environment or to municipal sewer systems. Permits are also required for process equipment (activated carbon or catalytic oxidation) discharging effluent to the atmosphere.
Permits must of course match the treatment technology. Once the contaminant mass is identified, consideration of the physical nature and partitioning of the contaminant mix will then lead to selection of the most appropriate system for contaminant mass management.
And with a treatment system on the job around the clock, it may just help you sleep like a baby.