Environmental Restoration: Part 6 - Engineered Remediation

In Environmental Restoration: Part 6 - Engineered Remediation, you'll learn ...

• Understand how data collected during the various parts of the investigation program are used to support an assessment of the health related risks posed by the site
• The approach to developing viable engineering remedial alternatives to improve existing conditions
• Recognize the important distinction between identifying levels of contamination and identifying a risk to human health
• How to use the field data to identify the contaminants of concern

Overview

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Credit: 4 PDH

Length: 67 pages

This course, Part 6, is the sixth in a series of six sequential courses, Parts 1 through 6, that present the history and steps taken to remediate the environmental hazards created by the land disposal of chemical and radioactive wastes on the campus of a research institute.

The practice of shallow land burial of hazardous wastes was widely used throughout the US between the 1960s and the 1980s. However, since the late 1980s both federal and state legislations were promulgated requiring the environmental regulatory agencies throughout the US to investigate operating, decommissioned and abandoned landfills of all types having in mind the ultimate goal of mitigating the impacts these waste disposal sites have on the natural environment. This series of courses, are written from the perspective of a Manager who leads a team charged with the implementation of an environmental Remedial Investigation (RI), Feasibility Study (FS) and Engineered Remediation (ER) of a hazardous waste disposal site. The courses draw from numerous environmental investigations managed by the author across the US. As such, the scenarios that are presented are similar to those a professional environmental engineering practitioner faces in real life. The case that is developed here is used as an example and a vehicle to present and discuss concepts and project implementation strategies gained through years of experience. This information is not usually found or taught in traditional or standard academic courses dealing with environmental issues or investigations. In their entity this series of courses can be considered an implementation guide for conducting environmental investigations at hazardous waste disposal sites.

The environmental problems in the example scenario are those encountered at a decommissioned hazardous and low-level radioactive waste disposal site owned by a research institute. The presentations are sequenced in the order in which investigations would be conducted by an environmental consulting firm contracted to perform and supervise the work that would be done in order to assess the magnitude of the problem and develop appropriate mitigation strategies for the rehabilitation of the site. This course, Part 6: Engineered Remediation, briefly reviews the key points of the previous courses in the sequence (Parts 1 through 5), and presents the results of the risk assessment and feasibility study. This phase of work started with the performance of a risk assessment to determine if an emergency situation exists that would require immediate attention, and the development of a set of corrective action objectives to guide the engineering feasibility study. The engineering feasibility study starts by evaluating the "No Action" alternative. This assessment is required by the Environmental Protection Agency (EPA), and includes addressing what may happen if nothing is done at the site. The "No Action" alternative is considered the baseline against which the other remediation options are compared.

The following step considered the nature and extent of existing institutional control measures to assess their adequacy to protect humans from inadvertently contacting the waste, or the plume of contaminants. Institutional controls also include ensuring that records of the site contents, spatial distribution of trenches and boundaries of the waste disposal area exist in several state and federal government repositories. These steps are taken to ensure that no one "forgets" that there is hazardous and radioactive waste buried in this area. The next stage involved the identification of a universe of appropriate engineering options for the remediation of the waste disposal area and the down-gradient plume of contaminated groundwater. The technical and regulatory feasibility of the proposed options are first evaluated to determine their relative effectiveness in mitigating existing conditions. Then, based on an assessment of overall appropriateness and cost effectiveness, a preferred engineered option is selected for inclusion in the Corrective Action Plan that is submitted for regulatory review and approval prior to implementation. The process is somewhat more complex because engineering alternatives are considered both individually and in combination and by the inclusion of auxiliary measures that could enhance the overall performance of the selected engineered remediation option.

Following regulatory review and approval, the proposed measures are cleared for implementation. The final design drawings are then prepared and construction can proceed in accordance with the established specifications. Following completion of the the construction, effectiveness of the engineered remediation measures is ascertained and documented through the results of the ongoing monitoring program. The monitoring program is usually continued for a period of at least five years following the implementation of the corrective measures to ascertain that the contaminant levels have dropped to below the applicable regulatory limits.

Specific Knowledge or Skill Obtained

This course teaches the following specific knowledge and skills:

• Understand how data collected during the various parts of the investigation program are used to support an assessment of the health related risks posed by the site
• The approach to developing viable engineering remedial alternatives to improve existing conditions
• Recognize the important distinction between identifying levels of contamination and identifying a risk to human health
• How to use the field data to identify the contaminants of concern
• How to assess the toxicity of the contaminants of concern
• Performing an exposure pathway assessment
• Characterizing the risk to human health
• How to determine if an emergency situation exists
• How to develop corrective action objectives
• How to use the corrective action objectives to guide the Feasibility Study
• Evaluation of the technologies for plume control and source control
• How to develop a Corrective Action Plan
• How to obtain the necessary Regulatory approvals
• How to proceed to the design and construction phase of the project
• Evaluating the effectiveness of the remedial measures that were implemented
• Understand why there is no "one size fits all" approach to dealing with the remediation of old hazardous and radioactive waste disposal sites

Certificate of Completion

You will be able to immediately print a certificate of completion after passing a multiple-choice quiz consisting of 26 questions. PDH credits are not awarded until the course is completed and quiz is passed.