- ELIOT COOPER
Pilot tests and design optimization tests (DOT) are intended to optimize remediation project design and reduce costs, but often they’re treated as an unnecessary delay and cost before real work begins. Many consultants question the utility of these smaller scale remediations, but they’re an important step in evaluating if the full-scale design will meet clean-up expectations at the cost estimated. In this blog post, I’ll explain how these tests improve the design, implementation, and results of injection remedies.
Next week, I’ll be doing a deep dive into how injection of emulsified zero valent iron (EZVI) can be used to treat chlorinated solvents. Register for the webinar, Struggling with CVOC Source Zone Treatment? Learn How NASA Figured It Out, and submit your questions ahead of time for a chance to win a $50 UberEats gift card.
There are many reasons to consider pilot testing, and they almost always outweigh the inconvenience of performing them. Some of those reasons include:
There are times, however, that the data gleaned from pilot testing has limited utility. Based on our experience, extrapolating that data to predict overall full-scale remediation performance is often hindered by…
Many of us are familiar with pilot testing but less so with DOT. Pilot tests are usually performed to decide to move forward with a remedy, while DOTs are performed to optimize the remedy/options chosen. DOT can save consultants a lot of headaches (and unnecessary expenditures) if properly conducted. Some of the reasons to consider conducting a DOT include:
Based on past experience, DOTs are usually successful in lowering full scale costs, as well as avoiding increased costs associated with unexpected conditions or slower performance in the field.
A DOT can often be conducting during the initial days of the project (depending on the full-scale project that require optimization), assuming no change in equipment mobilized will be required or would be readily available if needed.
During a pilot test and/or DOT, some of the variables that can be optimized are:
There’s risk involved in mobilizing to a site where injection hasn’t been conducted before. There’s also risk in adopting a new amendment or delivery approach. Either scenario can result in significant cost overruns and less effective remediation outcomes.
That’s why testing is so important. While it may seem like a cost saving measure to skip testing, it typically results in increased life cycle costs. These costs arise from unscheduled injection events or having to change the overall remediation approach.
It may not always be possible to reach a definite conclusion that remediation goals can be met—site heterogeneity and logistics can play too large a role to predict outcomes with certainty. In these instances, the pilot test will be able to provide confirmation of adequate amendment distribution, contact, residence time, and temporary reduction of the dissolved phase contaminants. Where matrix diffusion at heterogeneous sites is an issue, extrapolation based on additional soil sampling reductions will be required to estimate the overall number of events that will be required.
Moving into full scale remediation without testing is like building a chemical process plant without a startup/shakedown period: you may have a completed structure, but it will almost certainly require costly modifications along the way to ensure it can accomplish your goals.
Looking at a pilot test as just another check box that is needed to satisfy regulators will not help you manage full-scale risks or optimize costs. Designing the test and having realistic expectations of how the results will help optimize your full-scale remedy is critical in achieving project success.
If you’d like to learn more about how to successfully achieve your remediation goals via injection, join me for next week’s webinar, Struggling with CVOC Source Zone Treatment? Learn How NASA Figured It Out. If you’re unable to make it, register anyway and we’ll send you a link to the recording so you can watch at a more convenient time.