Vince R. Vermeul

Contaminants of Potential Concern in the 300-FF-5 Operable Unit: Expanded Annual Groundwater Report for Fiscal Year 2004

This report satisfies requirements in the Operations and Maintenance Plan for the 300-FF-5 Operable Unit (DOE/RL-95-73, Rev. 1) to provide detailed information, beyond that provided in the regular annual groundwater report (e.g., PNNL-15070), on groundwater conditions. The purpose is to characterize current conditions; provide a basis for changes to the monitoring schedules; and provide technical information to support the second 5-year review of the record-of-decision for the operable unit. Key topics include historical trends in the levels of various contaminants; updating the list of contaminants of potential concern; conceptual site models for uranium (300 Area) and tritium (618-11 waste site sub-region); performance of the interim actions under the current record-of-decision; and analysis of the applicability of Monitored Natural Attenuation as a remedial action alternative.

Treatability Study of In Situ Technologies for Remediation of Hexavalent Chromium in Groundwater at the Puchack Well Field Superfund Site, New Jersey

This treatability study was conducted by Pacific Northwest National Laboratory (PNNL), at the request of the U. S. Environmental Protection Agency (EPA) Region 2, to evaluate the feasibility of using in situ treatment technologies for chromate reduction and immobilization at the Puchack Well Field Superfund Site in Pennsauken Township, New Jersey. In addition to in situ reductive treatments, which included the evaluation of both abiotic and biotic reduction of Puchack aquifer sediments, natural attenuation mechanisms were evaluated (i.e., chromate adsorption and reduction). Chromate exhibited typical anionic adsorption behavior, with greater adsorption at lower pH, at lower chromate concentration, and at lower concentrations of other competing anions. In particular, sulfate (at 50 mg/L) suppressed chromate adsorption by up to 50%. Chromate adsorption was not influenced by inorganic colloids.

Drilling Specifications: Well Installations in the 300 Area to Support PNNL’s Integrated Field-Scale Subsurface Research Challenge (IFC) Project

Part of the 300 Area Integrated Field-Scale Subsurface Research Challenge (IFC) will be installation of a network of high density borings and wells to monitor migration of fluids and contaminants (uranium), both in groundwater and vadose zone, away from an surface infiltration plot (Figure A-1). The infiltration plot will be located over an area of suspected contamination at the former 300 Area South Process Pond (SPP). The SPP is located in the southeastern portion of the Hanford Site, within the 300-FF-5 Operable Unit. Pacific Northwest National Laboratory (PNNL) with the support of FH shall stake the well locations prior to the start of drilling. Final locations will be based on accessibility and will avoid any surface or underground structures or hazards as well as surface contamination.

Site Characterization Plan: Uranium Stabilization through Polyphosphate Injection

An initial feasibility study of options to treat the uranium plume at the 300-FF-5 Operable Unit considered hydraulic containment, slurry wall containment, and groundwater extraction as potential remedial action technologies. None were selected for interim action, and reduction of contamination levels by natural processes was considered a viable alternative while source removal actions continued. Subsequent planning for a Phase III feasibility study focused on methods that would reduce the concentration of uranium in the aquifer, including multiple methods to immobilize uranium using chemical-based technologies. Based on an initial technology screening, the polyphosphate technology was identified as the best candidate to treat the for further evaluation and selected for treatability testing. The overall objective of the polyphosphate treatability test is to evaluate the efficacy of using polyphosphate injections to treat uranium contaminated groundwater in situ. The objective of the work elements included in this site characterization plan is to collect site-specific characterization data that will be needed to design and implement a field-scale demonstration of the technology.

Treatability Test Plan for an In Situ Biostimulation Reducing Barrier

This treatability test plan supports a new, integrated strategy to accelerate cleanup of chromium in the Hanford 100 Areas. This plan includes performing a field-scale treatability test for bioreduction of chromate, nitrate, and dissolved oxygen. In addition to remediating a portion of the plume and demonstrating reduction of electron acceptors in the plume, the data from this test will be valuable for designing a full-scale bioremediation system to apply at this and other chromium plumes at Hanford.

Project Work Plan: Hanford 100-D Area Treatability Demonstration - In Situ Biostimulation for Reducing Barrier

This work plan supports a new, integrated approach to accelerate cleanup of chromium in the Hanford 100 Areas. This new approach will provide supplemental treatment upgradient of the ISRM barrier by directly treating chromium and other oxidizing species in groundwater (i.e., nitrate and dissolved oxygen), thereby increasing the longevity of the ISRM barrier and protecting the ecological receptors and human health at the river boundary.