Bench-Scale Testing
In Bench Testing we assess a proposed treatment technology on a small scale, typically using soil and/or groundwater samples from the site in question.
We test & analyze the treatment processes, compare results and use the data to optimize remedial designs.
At Vertex we complete bench-scale testing in-house. We determine the relative effectiveness and optimal dosing of various additives and how effective they are on the contaminant mix present in site specific soil and groundwater samples. This testing is routinely done to develop a refined remedial design to for a given site. A major benefit is improved accuracy of cost estimates and expected time-frames to complete the on site remediation work.
We recommend Bench Scale testing on most sites. The larger and more complex a site is, the more important bench testing becomes. High variability in soil types, contaminant concentrations, and contaminant types types creates more unknowns and assumptions. Bench Scale testing improves clarity and confidence in the treatment approach.
On the contrary. Some tests we conduct come with minimal expense (costs are hundreds of dollars). Some tests are a little more involved.
The important thing to note is that Bench Scale testing leads to savings from improved design and much more efficient application of technologies at the field scale. A relatively small investment upfront, often prevents costly mistakes when later implementing technologies at the larger scale.
For small, simple, or routine projects, Bench Testing may not be recommended. Vertex staff can help you assess whether Bench Scale testing makes sense for your site.
Types of Testing
We employ a variety of techniques to assess treatment of your soil and groundwater samples at the Bench Scale. Each has its own use, benefits, advantages, and disadvantages.
Natural Oxidant Demand Testing
Vertex offers NOD testing for various oxidants, such as sodium and potassium permanganate, sodium persulphate, hydrogen peroxide, etc.
In-situ Chemical Oxidation (ISCO) is often highly subject to the Natural Oxidant Demand (NOD) of the soil, bedrock and/or groundwater. Just as chemical oxidants react with contaminants of concern, they also react with organic and inorganic constituents present in the subsurface formation.
In some cases the NOD of the subsurface formation is much higher than that of the contamination that is present. This NOD must be “overcome” by the oxidants before the contaminants can be remediated. Therefore, it is often important to understand the NOD of the soils at a site.
Oxidant Testing
Vertex offers in-house oxidant testing, usually conducted on groundwater samples collected from a site, to analyze and monitor the concentration of oxidants in the sample over time.
All oxidants degrade in the subsurface over time as they react with the subsurface formation and the contaminants that are present. In many cases, more than one application of oxidants is required to meet remedial objectives. The length of time that the oxidants will remain active in the subsurface is site specific and difficult to predict.
Testing at the Bench Scale allows remediation programs to be completed in a more timely manner by minimizing “downtime” (i.e., we can predict when the oxidants have been used up) via scheduling subsequent applications of oxidant with more accuracy.
Custom-Designed Testing
Vertex also offers custom-designed testing for in-situ remediation programs.
These tests can involve assessing the effectiveness of different treatment trains. For example, we may wish to assess a switch in remediation method from chemical oxidation to aerobic bioremediation to determine if efficiencies are gained.
We also conduct completely customized testing, designed around the needs of the project.
For example, Vertex recently completed testing on the effect on consolidation of highly organic soil resulting from the injection of a strong solution of sodium persulphate.
Vertex has also designed customized tests that can be completed in the field. Some examples: we have developed small scale tests to confirm Zero-Valent Iron (ZVI) content during direct placement; another test we developed confirms the presence and relative quantity of mobile and non-mobile free-phased product in soil.
Benefits of Bench-Scale Testing
- Cost: Ensuring your design will produce the desired results in the lab. If not, by simply changing any processes at the bench-scale level we can avoid improperly spending tens if not hundreds of thousands of dollars at full-scale.
- Time: Ensure the plan matches the expected time-frame and budget to avoid unwanted scheduling errors.
- Scale: It’s far less painful (costly) to make corrections at a small scale. Adjustments at the small scale will lead to savings at the large scale.
Read more about the value of bench-scale testing with this article.
