Soil and Groundwater Remediation Services  

General Overview

HEA has experience with scores of soil and groundwater investigations and remediations. Our group is comprised of hydrogeologists, geologists, environmental scientists, engineers and project managers whose goals are to reduce data from assessment projects and when necessary, design, construct, operate and maintain remediation systems until closure of the project.

The first position in reviewing a potential remediation project is to develop the goals of the project: Is remediation necessary? Are there “no action” alternatives which can meet a state or federal cleanup guideline while serving all concerned parties and significantly controlling capital expenditures? Project endpoints can sometimes be met without implementing a costly remediation.

When remediation is necessary, it is the goal of the project manager to select the proper team from the group of remediation specialists. Organizing a strong project team is crucial for the success of the project. Together, the remediation team has the responsibility of supplying its customers with “no further action” strategies, or full remedial design and implementation services until project closure.

Remedial designs

Remedial designs which may be implemented by the remediation team include:

·        Pure Oxygen Injection Systems

·        Air Sparging and Soil Ventilation Systems

·        Dual Phase Extraction Systems

·        Bioremediation Processes: in situ and ex situ

·        Groundwater Removal and Treatment

·        Chemical Neutralization and Stabilization

·        Dual Pump LNAPL Recovery Systems

·        Off-gas Treatment, Catalytic Oxidation

·        Soil Containment: Slurry Walls, Caps

·        Construction Management: Excavation and Disposal, Treatment Cell Construction    

The Remediation Process

The remediation process is actually part of a much larger planning event that involves understanding the potential regulatory, technical, and political forces that may affect a project. The ultimate goal is to develop a written project strategy between the customer and environmental consultant/contractor that defines the short and long-term goals of the project.

STEP 1: Identifying the driving forces behind the need for any action

Regulatory Driving Forces

·         soil/groundwater/air cleanup goals (local, state, federal)

·         site background conditions

·         environmental actions to date

·         sensitive receptors, long term exposure scenarios

·         health risk considerations

·         interim remedial actions

·         past acceptable remedial action measures

·         reimbursement potential

·         knowledge of the regulators

Technical Driving Forces

·         hydrogeologic/geologic environment

·         potential contaminants involved

·         transport mechanisms

·         health and safety

·         interaction of mixed wastes

Political Driving Force s

·         third party impact by contaminants

·         legal obligations

·         budgetary and time constraints

·         media exposure/community relations

·         real estate strategy; sell/buy

·         ongoing operation of facility

·         future liabilities

STEP 2: Remedial Investigation- Definition of the Release

The goal is to collect the maximum amount of information with the smallest amount of expenditure. This is usually called the site investigation or assessment. A site investigation will tell us:

·         Soil Type,  Hydrogeology       

·         Contaminant Distribution     

·         Contaminant Mass, Transport Pathways

·         Conceptual suitability for remediation techniques

·         Sensitive Receptors

STEP 3: Development of Remedial Goals

The idea is to develop a clean-up strategy based on correct information. This strategy incorporates the real or perceived hazards related to the release; the impacts to sensitive receptors that have or will occur; the risk to human health and the environment; and finally determining the closure process.

Closure is our goal and is a negotiated set of targets worked out with the State/Federal regulators that will lead to a “clean bill of health”. The closure process may have stipulations that certain levels of chemicals can remain in soil and groundwater based on little or no risks to human health and the environment.

STEP 4: Remedial Technology Selection and Implementation

This is typically the creation of a corrective action plan(CAP) that stipulates the technology being used, why, how much it will cost, how long it will take. The CAP includes a full engineering design and implementation schedule.

STEP 5: Operation, Optimization, and Closure Sampling of the Remedy

This step accounts for keeping the remedial system operating, monitoring key parameters, adjusting the system to changing conditions, and planning the closure. Many times the closure process will include using natural-occurring mechanisms such as:

·         natural attenuation

·         natural biodegradation processes

It is essential that the closure strategy is kept as the ultimate goal of the project, and be continually re-evaluated under state or federal regulations, as additional data becomes available.