Choosing the best groundwater remediation method for your community

Groundwater is an essential source of drinking water and irrigation. Contamination occurs when chemicals seep into the soil from petroleum products, landfill waste, fertilizers, pesticides, leaking underground storage tanks and other sources. Groundwater contamination is often hard to detect and over time can cause severe consequences, including lead poisoning, cancer, ecosystem damage, water shortages and crop damage or loss.

After the source of contamination has been identified and eliminated, there are several mechanisms to treat the groundwater. It can be treated in place (in-situ) using one or more remediation methods. They might also pump it above ground (ex-situ) for treatment before disposal or returning it to the aquifer. In some cases, physical barriers can be installed to stop contaminants from spreading. Or teams can monitor the natural attenuation of contaminants once the source has been eliminated.

This blog post describes the most common groundwater remediation methods and offers guidance on determining the best option for your site.

Types of groundwater remediation methods
Air sparging	Air sparging is an effective method for treating groundwater contaminated with semi-volatile and volatile organic compounds. Injecting – or sparging – air into the aquifer generates turbulence in the contaminated groundwater zone, which facilitates the volatilization of contaminants. Air sparging also increases the oxygen content in groundwater, which can improve the aerobic degradation of contaminants.
Pump-and-treat	The pump-and-treat method is a widely used and relatively low-cost groundwater remediation technique. It involves pumping groundwater from wells into an above-ground system, then filtering and treating it to remove contaminants like fuel oils, dissolved chemicals, metals and industrial solvents. The treated water is then reintroduced or disposed of off-site.
Bioaugmentation/biostimulation/bioventing/biosparging	Bioaugmentation is an effective and relatively low-cost method highly adaptable to site-specific conditions. It employs microorganisms to metabolize organic contaminants present in ex-situ or in-situ environments. The biostimulation technique can further stimulate or enhance microbial activity by adding amendments like nutrients, air, organic substrates, electron donors/acceptors and other compounds. Adding air and oxygen flow, which is known as bioventing, stimulates the natural in-situ biodegradation of hydrocarbon derivatives. Injecting air under pressure (biosparging) increases the oxygen concentration, which accelerates the rate of degradation of contaminants.
Carbon absorption	Carbon absorption is an in-situ, short-term and low-cost groundwater remediation method. It involves absorbing contaminants with activated carbon, which has a high absorption capacity for contaminants like petroleum hydrocarbons, fertilizers, pesticides and chlorinated solvents. Contaminants are then degraded through reactive chemical or biological amendments.
Ion exchange	The ion exchange method is effective for treating perchlorate-contaminated groundwater. It uses a resin bed of functional ionic groups that capture perchlorate anions in contaminated water and release harmless chloride ions. The cost-efficiency of this technique varies depending on variables like the volume of water, contaminant concentration and more.
Containment	The containment method is commonly used at Superfund sites. It involves installing vertical, impermeable barriers below ground to prevent contaminated groundwater plumes from migrating to wetlands, streams and drinking-water wells.
Institutional controls	Administrative and legal controls are used to establish restrictions to minimize the potential exposure of groundwater contaminants at redevelopment sites. This technique can be cost-effective when engineers include them in the initial site design. Examples of institutional controls include well-drilling prohibitions, building and excavation permits, zoning restrictions, easements and covenants.
Alternative water supply	This method involves using alternative water supplies like bottled water and individual treatment units to avoid contaminated water. It’s typically a temporary measure used while cleaning up contaminated groundwater, though permanent alternatives may be used when cleaning up the original source proves too expensive or difficult.

Determining the right groundwater remediation method for a site

Choosing the appropriate groundwater remediation technique for a site depends on situation-specific factors like the type of contaminants, the permeability and porosity of the soil, local hydrogeological conditions, area of impact, cleanup goals and more. It requires a thorough economic evaluation of all viable remediation techniques. Factors influencing the right groundwater remediation technique include:

Site investigation cost.
Preliminary and feasibility study costs.
Planning and engineering.
Construction costs.
Reactive material costs.
Monitoring requirements.
Operations and maintenance.

How Fehr Graham can help your community with groundwater remediation

Fehr Graham is committed to ensuring communities across the U.S. have access to safe, reliable drinking water. We have a well-established success with numerous groundwater remediation methods. We're proud of our ability to meet the needs of our clients and provide ongoing support during every phase of a remediation project. One of our past projects involved an Environmental Site Assessment that led to the Dixon Iron & Metal cleanup. We have expertise in water engineering and brownfield remediation. Our team of licensed engineers and environmental experts will help you with groundwater remediation projects. We can even help secure funding.

To learn about how Fehr Graham can help you with groundwater remediation, contact us or call 920.453.0700.

Dillon Plamann is a Project Hydrogeologist who helps with soil and groundwater investigations, remedial activities, due diligence and building material assessments. He also works on reports, work plans, proposals, budgets, and Phase I and II Environmental Site Assessments. Reach him at This email address is being protected from spambots. You need JavaScript enabled to view it..