The summary
- Biological in-situ technologies allow companies to address ESG goals by repairing/restoring the environment without disrupting operations.
- Incremental Sampling Methodology outperforms standard Phase II Environmental Site Assessments by mapping hydrocarbon plumes, reducing false positives and providing more robust estimates of hydrocarbon concentrations.
- Natural Source Zone Depletion (NSZD) is a key management technique allowing companies to improve decision making and focus resource spend on actions that make a difference.
- The Soil Sense allows organizations to adopt regenerative business practices and confidently deal with legacy sites by using Natural Source Zone Depletion.
The Genesis of the Soil Sense
In-situ technologies can clean up contaminated sites, while allowing above and below ground infrastructure to operate. So, you could operate a retail store, pipeline, or gasoline station and remediate the environment simultaneously. With no disruptions to operations, businesses can go beyond remediation and achieve environmental restoration. However, the real benefit of these technologies is their early detection capabilities enabling a proactive approach by detecting contamination leaks before they become an environmental or costly problem. In essence, In-situ builds an insurance policy with mother nature (watch out for that deductible!).To solve any problem, you need to understand the problem in detail and this principal is no different when remediating or restoring soil. To truly tailor a site-specific remediation strategy, you must “see” the soil first. While seeing the surface of the soil is the easy part, it’s gaining a visual of sub-5 meters in the soil bed that is the challenge but is essential. “Seeing” the soil bed is met with balancing the need to maximize the collection of data while minimizing the cost and it’s at the perfect point of balance between this data challenge and the cost challenge that the Soil Sense was developed.
The Data Challenge
For example, an average contaminated site is about two Olympic swimming pools full of soil (about 5,000 m3 for the number-philes out there). The type, amount, and extent of contamination is investigated through government-regulated studies known as Phase II Environmental Site Assessments (ESAs). In these ESAs, researchers will collect 5 different tablespoons of data, and then measure how much pollutant is in the tablespoon. An intensive investigation might collect up to 10 tablespoons of soil every two years. This limited sample size provides no where near the quantity or quality of data that is needed to determine how contaminated a site is and even the very best scientists and engineers in the world would struggle to understand and plan based on such little data.
From the start we planned for data scarcity challenges forcing us to think outside the box and apply the excellent Incremental Sampling Methodology (ISM) work by the Interstate Technology Research Council (ITRC) to hydrocarbons in clay soils. The premise of ISM is to collect a bunch of small samples to make one big sample1.
In applying the ISM method to our challenge, we noted it strongly outperformed the standard Phase II Environmental Site Assessments in the following three areas:
1. Mapping hydrocarbon plumes (where we know how far the contaminant spread out),
2. Fewer false positives (detecting contaminants when they weren’t there),
3. Accurate estimates of hydrocarbon concentrations (how much is there), compared to a Phase II ESA.
The Cost Challenge
The application of ISM solved the tablespoon problem, but the cost problem remained, the costs associated with repeatedly drilling sites and the disruption to site operations were significant.
As we began to build a business model linked to remediation, on-going drilling costs presented a large barrier to the project. An average site will cost between $10,000 to $20,000 per year for groundwater monitoring while collecting and analyzing soil cores (or tablespoons of soil) can cost around $4,000 per core. The cost for even a handful of cores at a site can add up quickly, so somehow, we needed to be able to estimate how a site was responding to new technologies without breaking the bank.
Focusing on the Solution
We were not alone in this. Others had recognized, as early as 1999 that there was a need to collect more robust estimates of hydrocarbon dynamics in the soil. In the early 2000’s, a large group of environmental professionals developed an approach called Natural Source Zone Depletion (NSZD) which represented the natural decay of hydrocarbons into carbon dioxide and methane. Many studies were used to demonstrate the scientific foundations of NSZD. Guidance documents on how to measure NSZD were developed by the ITRC and the Commonwealth Scientific and Industrial Research Organisation (CSIRO). The core foundation of NSZD is that methane is generated as hydrocarbons degrade near the water table. The methane moves towards the surface, where it is converted to carbon dioxide.If we measure carbon dioxide emissions at a contaminated site, we can then estimate how much hydrocarbon is being depleted in the soil. Around 70% of hydrocarbon degradation occurs near the water table (termed the vadose zone and/or capillary fringe by soil scientists). Consequently, NSZD was a compelling data-point for teams managing contaminated sites.One of the methods to gauge NSZD is to measure gas concentrations in the soil profile. During our time researching soil in the Arctic, we had used something very similar to measure greenhouse gas concentrations in soils, but the system was heavy, cumbersome, and expensive2. We needed a cheap reliable way to measure the key NSZD gasses produced during hydrocarbon depletion.
Fast-forward a few years and more than a few trials and errors, and the Soil Sense was born.
By combining next generation (read: cutting edge) sensor technology, EMS could measure soil gas profiles of not only NSZD indicators, but also hydrocarbon concentrations and soil parameters continuously. We partnered that with a new communication technology called LoRa (low-power wide-area) network modulation. In so doing, we can monitor the Soil Senses from the comfort of our office chairs, with new data every 30 minutes on NSZD markers, soil properties, and hydrocarbon content.
Wait a sec, this could be really valuable!
We always saw the Soil Sense as a helpful tool to rapidly prove/disprove remediation approaches. But our partners and customers, quickly realized that the Soil Sense would be even more valuable for applications where there is uncertainty around starting or stopping remediation. The ability to detect and quantify hydrocarbons in the soil, and to move installed Soil Senses and around to key areas within a contaminated site, allows our customers to map out complex sites, make decisions and then respond as the data comes in.
The development of the Soil Sense put us on the path to building a valuable system that would allow companies to track progress on remediation and fulfill its ESG reporting requirements, with a real emphasis on the E, Environment.