The Remedial Action Operation (RA-O) phase involves operation and maintenance (O&M) of the remedy, along with remedy performance assessments and monitoring. Remedy performance should be evaluated routinely and optimized to achieve the Response Complete (RC) milestone in a cost-effective manner. Sites may also transition to the long-term management (LTMgt) phase where conditions do not allow for unrestricted use.
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For remedies requiring O&M, the site transitions to the RA-O phase after completion of Remedial Action-Construction (RA-C). The RA-O phase involves O&M, monitoring actions, and continual optimization of the remediation system and conceptual site model (CSM).
During the RA-O phase, the remediation system is operated and/or chemical or biological processes are occurring leading to the cleanup objective identified in the Record of Decision (ROD)/Decision Document (DD). The RA-O may include active remediation that requires an extended operational timeframe to reduce contaminants to cleanup goals or passive remediation technologies such as monitored natural attenuation (MNA). As part of a treatment train approach, the remedy may also transition over time from active to passive technologies. Depending on the flexibility of the existing ROD/DD, implementing remedy changes and/or transitioning technologies during the RA-O phase requires a memo to file, an Explanation of Significant Differences (ESD), or a ROD amendment.
NAVFAC has several policies and guidance documents that guide the RA-O phase including the DON Policy for Optimizing Remedial and Removal Actions at All DON Environmental Restoration Program Sites. This policy provides for a systematic approach with an emphasis on continual evaluation of remedy performance, lifecycle cost, and trend analysis. It also endorses the use of green and sustainable remediation (GSR) metrics for tracking and reducing the overall environmental footprint during the RA-O phase including energy, material, resource, and fuel usage. The NAVFAC Guidance for Optimizing Remedial Action Operation presents a step-wise process for optimizing RA-O projects.
Monitoring conducted during RA-O should focus on collecting performance data to compare to the exit strategy and to assess remedy protectiveness. Exit strategies are means of determining when it is time to stop, modify, or change a particular technology, or terminate all remediation actions, based on the achievement of previously established performance objectives. A Monitoring Plan must be developed to clearly state the performance objectives of the RA-O and what specific data will be collected to satisfy those objectives. Further detail is provided in the Environmental Protection Agency’s (EPA’s) Guidance for Monitoring at Hazardous Waste Sites: Framework for Monitoring Plan Development and Implementation (OSWER 9355.4-28). The NAVFAC Management and Monitoring Approach (MMA) may be used for the preparation of well-written annual reports during the RA-O phase. DON Guidance for Planning and Optimizing Monitoring Strategies should be consulted to ensure monitoring programs are periodically optimized to cost-effectively support their monitoring goals without compromising program and data quality.
The management and maintenance of land use controls (LUCs) may also occur during this phase. For sites where remedial action objectives are not yet achieved, LUCs and Five-Year Reviews may also be required during the RA-O phase. Additional information on applicable policies and guidance can be found on the Five-Year Review Web page.
The RA-O phase is complete when cleanup goals specified in the ROD are met. Formal concurrence that the site has achieved the Response Complete (RC) milestone is essential to ensure that DON and regulatory agencies agree that cleanup goals have been achieved at the site. The Remedial Action Completion Report (RACR) formally documents the achievement of cleanup objectives. Site Closeout (SC) is achieved if the site obtains unlimited use/unrestricted exposure (UU/UE) at the RC milestone, otherwise LTMgt is needed. Additional information on tools applicable to long-term monitoring and other related activities can be found on the LTMgt Web page.
For more information, Chapter 10 of the DON Environmental Restoration Program Manual details RA-O considerations.