Lessons from East Palestine in Horizontal Treatability

By Tomas Will, Sr. Environmental Scientist

 

The chemical release associated with the train derailment that occurred on February 3rd has garnered nationwide attention and there are some lessons from East Palestine in horizontal treatability. The incident has raised concerns over air quality and water quality in the surrounding areas of Ohio and Pennsylvania. While a Preliminary Remedial Action Work Plan has been prepared, at the time of this article, the activities being performed by environmental professionals are still focused on emergency response. As the response to this release incident progresses and more is known about the potential soil and groundwater contamination, the continued assessment and potential remediation of this site will become increasingly important. While the overwhelming majority of release incidents do not typically receive the same level of attention that we are seeing in East Palestine, they too have critical needs for assessment and remediation. Below we will look at various ways that horizontal wells have been used as an integral tool in treating contaminated soil and groundwater at sites with chemical releases.

 

Challenges to Soil and Groundwater Remediation

In East Palestine, we see many challenges to soil and groundwater remediation that are shared across many other sites. The release occurred in an urban setting where various areas have limited access for equipment, several businesses and residences containing occupied structures are present in the area, multiple surface water bodies are in the vicinity, and the dimensions of the groundwater plume are likely to be relatively large. Horizontal remediation wells are often used to address these site conditions, among others. When faced with these types of challenges, horizontal remediation wells are often used for the following reasons:

• Horizontal wells allow significantly more screen to be placed within the contaminant plume, allowing for more efficient in-situ remediation performance.
• Horizontal wells would significantly improve the radius of influence produced by the remediation system.
• Horizontal wells provide more precise targeting of hot zones without being limited by access limitations at the surface.
• Horizontal wells prevent interruptions to business operations during horizontal well installation and subsequent operations and maintenance.
• Horizontal wells significantly reduce the total number of remediation wells required to be operated at once.

Horizontal wells offer the versatility to implement a wide range of in-situ remediation techniques to address contamination detected in soil and groundwater. While there are various technologies that are well suited to dealing with contamination found at the ground surface, once contamination enters the soil and groundwater, there are a number of strategies that have been used with horizontal wells to accelerate the achievement of remediation goals. In the case of chemical releases similar to what has been observed in East Palestine, horizontal remediation wells have been implemented to:

• Use air sparging techniques to volatilize VOCs and SVOCs in the groundwater.
• Use SVE techniques to capture vapors in the soil and prevent vapor intrusion into occupied structures.
• Use pump-and-treat groundwater extraction techniques to install a barrier well perpendicular to the groundwater gradient in order to control migration of contaminated groundwater towards sensitive receptors through hydraulic control methods.
• Use injection techniques to deliver the appropriate chemical amendments or microbial cultures to areas of contaminated soil and groundwater.
• And many more techniques which would apply to sites with different contaminants of concern.

 

Assessment

Horizontal wells can be used in various ways to help delineate contaminant plumes and quantify contaminant concentrations. Many sites present a number of challenges for assessment that are difficult to solve using traditional vertical drilling methods. These challenges include buildings and infrastructure preventing access for drilling equipment, surface water bodies preventing access for drilling equipment, and an inability to get drilling equipment within close proximity to the source area due to emergency response activities and/or imminent health hazards to remedial construction crews. Horizontal wells can be used to collect soil and groundwater samples in critical areas that can’t be easily accessed by any other means.

 

Do your projects face challenges that traditional technologies can’t easily remedy? Call our horizontal remediation well experts at 1-877-788-4479 to discuss your current project needs.