By Tomas Will, Sr. Environmental Scientist
How can you be sure that the remediation option selected for your site is the right fit? Even once a technically sound remediation technology has been selected, there are still important questions that remain to be answered regarding design and implementation. At Directional Technologies, we understand that no two sites are the same and there is no one-size-fits-all approach that will work effectively for every project. In this article, we review two projects of drastically different scales to demonstrate how horizontal wells solved challenges for both the consultants and their clients and provided cost-effective solutions. Using an approach that can be scaled to fit the project size, Directional Technologies helps consultants implement successful remediation strategies that provide superior results.
Case Study 1 – Former Drycleaner
Chlorinated solvent contamination was present in the soil and groundwater at the location of a former drycleaner in the western US. The site had recently been redeveloped and the new building owner was not eager to have vertical wells installed inside their new building. Additionally, there were concerns regarding disturbances to the new building tenants and the impression that might be created by any highly visible remediation activities. The consultant proposed a horizontal remediation system to their client in order to solve these problems.
The consultant selected Directional Technologies due to their experience designing site-specific horizontal wells. It was determined that the goals of the project could be achieved using only a single soil vapor extraction (SVE) horizontal well. Directional Technologies installed a SVE well totaling 160 feet in length with 90 feet of screen in the vadose zone. The 3-inch well was installed to a depth of 7 feet below ground surface. To minimize the potential for concerns from the tenants, the installation was conducted from a discrete location and was quickly executed in only two days. The horizontal well was able to be installed discretely from the back of the building without disturbing the building tenants and without any damage to new building. The horizontal well also provides far more well screen in contact with contaminated zones compared to a vertical well alternative, allowing for improved performance.
Case Study 2 – Bulk Fuel Terminal
A broad LNAPL plume was present at a bulk fuel terminal facility located in the southeastern US. The plume extended beneath a tank storage area, an office building, a warehouse building, and a nearby highway. The subsurface at the site contained multiple underground utilities as well as several large oil transportation pipelines. With operations at the facility running 24 hours a day, 7 days a week, the consultant’s client was in search of a solution that would minimize the impact to their busy operations. The consultant recognized that horizontal remediation wells would allow them to both drastically reduce the total number of wells needed, as well as eliminate the need for shutting down operations while remedial construction was underway. Directional Technologies was brought in to design a targeted approach that would safely manage the many subsurface utilities and also provide their expertise during the horizontal well layout and site-specific well screen design process.
Directional Technologies installed seven horizontal biosparge wells totaling over 3,500 feet in length. The 3-inch horizontal wells were installed to an average depth of 35 feet below ground surface and contained over 2,800 feet of screen in contact with the contaminant plume. The horizontal wells were completed using a “blind” installation technique that allows the wellbore to terminate in the subsurface at the end of the horizontal screen without the need for an exit point. The seven horizontal wells were installed from a common starting point to both minimize the footprint of the remedial construction as well as to reduce the costs of connecting the wells to the air sparge system. The entire installation was able to be completed without any impediment to facility operations and allowed for future operations and maintenance activities to be completed without causing business interruptions.
Conclusions
The advantages provided by horizontal wells are applicable to a wide range of projects and a diverse array of challenges. Whether you are worried about business disruption, concerned about complex site conditions, need to keep the project below the radar, or even just wonder if there might be a better way, horizontal remediation can be a great option. Additionally, there’s nothing quite like experience when tackling a problem that you may have not encountered before or when designing a creative solution to address a challenging set of objectives. Directional Technologies has designed and installed more than 1,000 horizontal remediation wells over the last 30 years, and they bring that experience to bear to help consultants every day.
We will help you evaluate a horizontal well solution and determine if it will be a great fit for your project. Call our horizontal remediation well experts at 1-877-788-4479 to discuss your current project needs or visit more on our website to reach out with questions, review case studies, and learn more.