By Tomas Will, Sr. Environmental Scientist

From an owner’s perspective, an environmental consultant who can effectively address their client’s business concerns while resolving their environmental problem stands out among the crowd. In addition to the obvious up-front costs, remediation activity can also carry costs associated with downtime and/or lost productivity at busy facilities. Therefore, when commercial and industrial companies select an environmental consultant to help them address their soil and groundwater contamination needs, they look for someone who has the expertise to both achieve remediation goals and help minimize costs to their business during remedial construction and subsequent O&M. In the case of one consultant’s commercial remediation project; they were able to effectively treat indoor air vapor intrusion while eliminating disruptions to the facility by using horizontal SVE wells.

Background and Setting:

An industrial facility had used in-ground degreaser pits as part of their longstanding operations, which resulted in significant TCE and PCE impacted soil and groundwater. The contaminant plume was located beneath a portion of a large manufacturing building. Based on various environmental investigations, vapor intrusion posed severe indoor air quality issues for workers and had to be dealt with; however, the interior layout of the facility was filled with machining equipment that was operated around the clock.

Problem:

The consultant was tasked with finding a way to effectively address indoor air concerns while also looking for ways to limit or avoid interruptions to the business operations within the facility. They began exploring designs for a traditional SVE system but were faced with costly challenges related to implementation due to the nature of the facility. Installation of an SVE system through traditional means would require moving large pieces of equipment and shutting down a portion of their operations for multiple days. Furthermore, some vertical SVE wells would not be able to be placed in the areas necessary to achieve ideal system performance due to unmovable equipment and the specific layout of the facility.

Solution:

The consultant had encountered similar challenges on previous projects and had used horizontal remediation wells to overcome them. Therefore, they reached out to Directional Technologies to assess potential designs for a horizontal SVE system. After reviewing several possible designs with DTI’s engineering team, they selected an approach to install blind (single-entry) horizontal wells from the facility exterior that could effectively access the contaminated vadose zone beneath the building slab in the center of the building.

Based on that collaborative design, three horizontal SVE wells were installed to depths between 6-9 feet beneath the building floor. The 3-inch diameter wells were installed with screens ranging in length between 150-300 feet. The entry points for the wellheads were installed anywhere from 10-70 feet away from the building exterior to avoid interference with exterior operations, specifically loading areas.

Using horizontal wells, the consultant found they could:

  • Eliminate impacts on ongoing industrial activity during remedial construction and future O&M, which saved their client money.
  • Reduce the total number of SVE wells required.
  • Access critical portions of the plume beneath the facility.
  • Allow significantly more screens to be placed in contact with the most highly concentrated portions of the plume, allowing for more effective remediation performance.

Conclusions:

Horizontal wells and a collaborative design process are an effective approach to win over your commercial and industrial clients by helping them save money and avoid interruptions to their facilities. With the proper equipment, techniques, and experience provided by Directional Technologies, horizontal remediation wells can be successfully implemented at sites with many restrictions that might otherwise make remediation technically or economically difficult or impossible.

Do your clients have business needs that they don’t want to have impacted by remediation activity?  Call our horizontal remediation well experts at 1-877-788-4479 to discuss your current project needs.