Senior Vice President, Environmental Engineer,
Tamzen Macbeth is a Senior Vice President and Remediation Practice Leader at CDM Smith. Tamzen with an interdisciplinary academic and research background in microbiology and engineering. She specializes in the development, demonstration and application of innovative, cost-effective technologies for contaminated groundwater. Specifically, she is experienced in all aspects of remedies from characterization to remediation for DNAPLs, PFAS, dissolved organic, inorganic, and radioactive contaminants under CERCLA and RCRA regulatory processes. She has expertise in a variety of chemical, biological, thermal, extraction and solidification/stabilization remediation techniques as well as natural attenuation. Her current work focuses developing combined technology approaches, and innovative characterization techniques such as high-resolution site characterization, mass flux and mass discharge metrics. Since 2004, Tamzen has contributed to the ITRC as a team member and instructor for 8 ITRC teams, including the recent Optimizing In Situ Remediation Performance and Injection Strategies.
State of the Practice: Optimized Amendment Injection Strategies for In Situ Groundwater Treatment
Restoration of contaminated aquifers using in situ remedial technologies, such as in situ bioremediation, in situ chemical reduction and in situ chemical oxidation, rely on effective amendment injection. To achieve successful treatment, delivering amendments and contacting contaminants is critical. Complex site conditions, such as geologic heterogeneity, hydrogeology and geochemistry affect contaminant distribution and transport and amendment injection technologies that do not adequately account for these phenomena often fail to achieve remedial objectives. The state of the practice for in situ injection includes many options for successfully delivering amendments under a variety of aquifer conditions. Central to this strategy is development of a conceptual site model (CSM) at an appropriate resolution to guide in situ remedial design – amendment selection, delivery approach, and the performance monitoring program. Innovations in the state of the practice and lessons learned from sites will be discussed and how these advances are used to improve cleanup and remedy decision making for in situ remedies.