Keller is a recognized leader in environmental remediation. Projects have been completed under RCRA, CERCLA, and TSCA regulations and with agencies such as the EPA, FERC, USACE, and hundreds of state and local entities. Our environmental remediation solutions help owners support safe redevelopment, infrastructure improvements, and regulatory compliance across a wide range of sites.
What is environmental remediation?
Environmental remediation involves treating, containing, or removing contaminated soil, groundwater, or vapor to reduce risk to human health and the environment. Remediation solutions are commonly required at industrial, commercial, infrastructure, and brownfield sites to address contamination, meet regulatory standards, or enable site reuse.
When is environmental remediation used?
Environmental remediation may be required when:
- Soil or groundwater contamination exceeds regulatory limits
- Redevelopment of brownfields or previously industrial sites is planned
- Construction activities risk mobilizing contaminants
- Sites require mitigation of vapor intrusion or groundwater migration
- Environmental controls are needed to protect adjacent properties or ecosystems
Environmental remediation may include ground improvement, groundwater control, or the installation of containment systems. While these solutions can also be used for purely geotechnical purposes, environmental remediation solutions are distinguished by their focus on regulatory compliance, contaminant management, and long‑term environmental performance.
Environmental remediation applications
Keller can help with redevelopment efforts of brownfields or landfills using geotechnical methods such as soil mixing, jet grouting, slurry walls, and water treatment systems.
Excavation and removal remain a leading method for remediating contaminated sites. Keller performs highly surgical and mass removal of impacted media, including soils, sediments, and chemical residuals. Moretrench Industrial, a Keller company, has specialty earthwork capabilities in materials other than typical soil. Many of our projects include a shoring system to ensure safety. Additional methods safely remove contamination adjacent to buildings, under power lines, and near active plant operations.
Stabilization can reduce the mobility of hazardous substances and contaminants in the environment through physical and chemical means. We use a unique blend of reagents to trap or immobilize contaminants within the contaminated soil or sludge.
The “CCR rule” requires the closure of all fly ash ponds by excavation and removal, regrading and capping, or a combination of a “hybrid” closure approach.
Keller has worked on over 30 ash pond closure projects and understands that fly ash is highly problematic, unstable, and sensitive to vibration when saturated. This can make excavation, handling, and disposal of this material challenging.
Keller uses various techniques at these facilities, including:
- Dewatering of ash
- Treatment of ash pore water
- Soil mixing and grouting methods for geostructural improvements in ash
- Environmental barrier/cutoff walls at the site perimeter
- Instrumentation and monitoring programs for construction safety and permanent site features
- Anchors, sheet piles, soldier piles and lagging for earth retention in ash
Challenges associated with the disposal and containment of mine tailings and waste can be addressed by solutions such as:
- Wick drains for tailings consolidation
- Seismic stabilization of perimeter embankments and dikes
- Cutoff walls for groundwater control and contaminant migration
- Water treatment
- Drainage and dewatering of tailings
Subsurface slurry trenches are installed using various equipment, including hydraulic / long-reach excavators, hydraulic and mechanical clams, trenching machines, and custom buckets. These cutoff walls can consist of soil-bentonite, soil-cement-bentonite, soil attapulgite, soil-cement and attapulgite, cement-bentonite, and concrete.
Passive treatment systems permit groundwater to flow through specific treatment media. Groundwater contaminants react with the installed treatment medium and are degraded, precipitated, or absorbed in situ, depending on the contaminant type and treatment system.
Passive treatment systems use naturally occurring environmental processes, chemical and biological, to cleanse contaminated waters. Some passive treatment systems we maintain include iron filing walls, funnel-and-gate systems, passive biotrenches, permeable reactive barrier walls, and built-in filtration systems.
Recovery treatment systems remove contaminants in groundwater, such as solvents, metals, fuel oils, or other regulated substances. Groundwater is pumped from extraction wells within the polluted groundwater plume to an above-ground treatment system. Some of the treatment system components then address contaminants using the following methods:
- Soil vapor extraction
- Oil-water separators
- Air stripping towers
- Granular activated carbon
- Thermal oxidizers
- Pumping systems
Soil treatment
Soil can be treated in place by mechanically blending natural soil with a binder to encapsulate constituents of concern. This is typically done using soil mixing techniques and is referred to as In Situ Stabilization (ISS).
Various reagents and reducers stabilize or oxidize contaminated soil, including triple superphosphate, buffering agents, cement, potassium permanganate, hydrogen peroxide, sodium percarbonate ZVI, and ferric sulfate. Each technique requires a mechanical mechanism to complete the treatment, using deep soil mixing rigs and traditional construction equipment to introduce the reagents.
Bioremediation projects are completed using in situ and ex situ techniques. In situ bioremediation, or bioventing, involves stimulating indigenous subsurface microbial populations to biodegrade organic contaminants. Ex situ techniques, including windrowing, are coupled with added nutrients to enhance the remediation of the media.
Why choose Keller for environmental remediation?
Keller brings environmental remediation experience together with geotechnical and construction capability to deliver solutions that work. We support projects that require careful coordination of remediation, earthwork, containment, and water management that help owners meet regulatory requirements and advance redevelopment or operational goals with an integrated approach.
Common uses
- Support redevelopment of brownfields and industrial property
- Control and treat contaminated water
- Prevent migration of contaminants through containment systems
- Consolidation of mine tailings
- Waste encapsulation and solidification
- Enable construction in environmentally sensitive areas
Related projects
Industrial and manufacturing
Bayway Refinery
Installation of a 600-foot long, permanent biopolymer collection trench and barrier curtain wall for environmental remediation at the Bayway Refinery.
Power
Four Corners CCR Impoundment
Four Corners Generating Station needed to increase the capacity of its CCR impoundment for a number of reasons. Keller installed wick drains to provide the necessary drainage for the project.
