Review of Amendment Delivery and Distribution Methods, and Relevance to Potential In Situ Source Area Treatment at the Hanford Site
The U.S. Department of Energy’s Hanford Site in southeastern Washington State is a complex of multiple facilities where historical release events in the Central Plateau area have resulted in subsurface contamination of the vadose zone, a perched-water zone, and underlying aquifer. Although some contaminants have already migrated through the vadose zone into the groundwater, contaminants remaining in the unsaturated zone are a potential long-term risk as a source for further groundwater contamination. Moreover, a perched-water zone located in the 200-DV-1 Operable Unit at Hanford creates further remediation difficulties. Remediation options are limited for contaminants located in the vadose and perched-water zones within the Central Plateau due to considerable depth, co-located contaminants, and complexities associated with physical and biogeochemical heterogeneities. Existing comprehensive reviews discuss potential remedial technologies relevant to Hanford Site conditions (e.g., deep vadose zone and perched water) and provide treatment technology recommendations. Many of the recommended in situ remediation technologies rely on introduction of amendments into the subsurface to achieve remedial goals. However, there are currently few review or guidance documents that provide a comprehensive look at mechanisms and considerations related to amendment delivery and distribution. This document summarizes amendment types, delivery techniques, subsurface access methods, and the applicability of delivery methods and amendments for specific subsurface target zones, including in the context of Hanford Central Plateau applications. Guidance on the appropriateness of a remedial technology for a specific site and contaminant is not included within this document. Rather, this document is intended to be used when considering remediation technologies and the associated amendments. An overview of amendment types (i.e., liquid, gas, and solids) and access/distribution methods used in subsurface remediation is provided, along with discussion of the maturity level (low, medium, or high), advantages, and limitations that relate to the potential effectiveness of each approach in the context of site-specific factors (subsurface geology, geochemistry, contaminant properties, etc.). There are many Hanford Site-specific factors that influence the suitability and appropriateness of amendment delivery strategies. Excluding amendment delivery approaches that are unsuitable for the Hanford context, each approach was assessed for applicability to the following target zones: unsaturated high permeability, unsaturated low permeability, perched water, saturated high permeability, and saturated low permeability zones. This compilation and discussion related to amendment delivery mechanisms provides a useful resource for evaluating remedial alternatives for source area contamination in the Hanford Central Plateau.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1684619
- Report Number(s):
- PNNL-29198; DVZ-RPT-0023-Rev.0.0; TRN: US2204454
- Country of Publication:
- United States
- Language:
- English
Similar Records
FEASIBILITY STUDY REPORT FOR THE 200-ZP-1 GROUNDWATER OPERABLE UNIT
Initial Site-wide Groundwater remediation Strategy of the Hanford Site, WA: Its Application, Lessons Learned and Future Path forward