Combined Remedies for Cost-Effective & Holistic Site Remediation

The effective remediation of complex sites often requires the use and integration of multiple remedy components. For example, many sites require a combination of in-situ treatment, excavation/earthworks, and or groundwater pumping and treatment to achieve the desired outcome. The cost-effective integration and sequencing of combined remedies requires a holistic approach grounded in a well-defined site conceptual model and thorough up-front planning. The planning must consider not only the technical challenges, expected effectiveness and interrelationships of various remedial components, but must also address cash flow, site logistics/constraints, safety, risk management, and schedule drivers. 

While there are many issues one must account for when managing combined remedy solutions, here are three of the top factors that may influence the strategy and timeline of your project. 

Balancing source remedy and plume management concerns 

Many projects require both source remedy and plume management components, which may involve different treatment sequencing or implementation durations and require access to different areas of a site. In addition, the design basis for the plume management component is often reliant on the approach and effectiveness of the source remedy. Depending on the site conditions and risk management/receptor considerations, it may be advantageous to implement and establish the effectiveness of a source remedy prior to addressing downgradient issues, or in other cases it may be necessary to establish plume containment prior to implementing a source remedy. In addition, certain combinations of technologies may require sequential implementation by design if varying redox or other geochemical conditions need to be established for technology effectiveness. For example, a source area in-situ chemical oxidation remedy must consider the potential impacts of associated geochemical conditions on a plume bioremediation remedy.

Challenging site logistics 

Site logistics may also drive decisions on the best combination of technologies or on the optimal sequence and duration of remedy implementation. At active facilities consideration must be given first and foremost to the safety of site and project personnel, and the ability to run day-to-day operations without interruption. Spatial constraints often require sequencing of activities simply because sufficient space is not available for simultaneous activities. Alternatively, site re-development is often the schedule driver and the various remedy components either need to be optimally sequenced in advance of construction activities or integrated into the construction program itself.  

Cash Flow 

Timing of the most capital-intensive remedy components is a key consideration from a cash flow perspective. In some circumstances, it may be feasible to defer large capital cost items such as high-volume soil excavation and disposal until later in the program. This requires consideration of other factors from a risk management perspective, to ensure the timing does not impede the technical effectiveness of other remedy components or increase life cycle costs.

Developing the right strategy for implementation of successful, cost-effective multi-remedy projects requires a precise balance of technical expertise, pragmatic decision making, and effective project management. Our understanding of the deployment and integration of remedial technologies coupled with our ability to customize robust site conceptual models with a holistic management approach, allows us to develop smart cost-effective remediation strategies for large, complex sites. Please reach out to me at if you want to discuss combined remedy strategies for your project.

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