Summary review of the chemical characterization of liquid and sludge contained in the Old Hydrofracture tanks, Oak Ridge National Laboratory, Oak Ridge, Tennessee

This report presents analytical data developed from samples collected from the five inactive tanks located at the Old Hydrofracture Facility (OHF) at the Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee. The samples were collected during December 1995 and January 1996. The purpose of the sampling and analysis project was (1) to determine whether the tank contents meet ORNL waste acceptance criteria, as specified in the Oak Ridge National Laboratory, Liquid Waste Treatment Systems, Waste Evaluation Criteria; (2) to determine various physical properties of the tank contents that would affect the design of a sludge mobilization system; and (3) to gather information to support a baseline risk assessment. The report focuses on the analytical results used to evaluate the tank contents with regard to nuclear criticality safety requirements and to regulatory waste characterization

FY 1995 remedial investigation work plan for Waste Area Grouping 2 at Oak Ridge National Laboratory, Oak Ridge, Tennessee

Field activities to support the remedial investigation (RI) of Waste Area Grouping (WAG) 2 at Oak Ridge National Laboratory (ORNL) include characterization of the nature and extent of contamination in WAG 2, specifically to support risk-based remediation decisions. WAG 2 is the major drainage system downgradient of other WAGs containing significant sources of contamination at ORNL. The RI of WAG 2 is developed in three phases: Phase 1, initial scoping characterization to determine the need for early action; Phase 2, interim activities during remediation of upgradient WAGs to evaluate potential changes in the contamination status of WAG 2 that would necessitate reevaluation of the need for early action; and Phase 3, completion of the RI process following remediation of upslope WAGs. Specifically, Phase 2 activities are required to track key areas to determine if changes have occurred in WAG 2 that would require (1) interim remedial action to protect human health and the environment or (2) changes in remedial action plans and schedules for WAG2 because of changing contaminant release patterns in upslope WAGs or because of the effects of interim remedial or removal actions in other WAGs. This report defines activities to be conducted in FY 1995 for completion of the Phase 1 RI and initiation of limited Phase 2 field work

A total-recycle expanded-bed bioreactor design which allows direct headspace sampling of volatile chlorinated aliphatic compounds

Summary A two-phase column system was developed, allowing direct headspace sampling of volatile chlorinated aliphatic compounds, including trichloroethylene, cis-and trans-l,2-dichloroethylene and vinyl chloride. Propane, methane and CO 2 were sampled in the same fashion. A comparison of two solid support matrices (crushed glass and anthracite coal) was performed. > 97 _+ 2070 of the trichloroethylene added to control reactors was still present following 12 days of operation. The bioreactor consisted of an expanded-bed column containing 70 g of 60/80-mesh substratum. The liquid phase was recirculated through the expandedbed column into a gas-recharge column fitted with a headspace sampling port which allowed direct sampling and subsequent quantification by gas-chromatography techniques

Biodegradation of Trichloroethylene in Continuous-Recycle Expanded-Bed Bioreactors

Experimental bioreactors operated as recirculated closed systems were inoculated with bacterial cultures that utilized methane, propane, and tryptone-yeast extract as aerobic carbon and energy sources and degraded trichloroethylene (TCE). Up to 95% removal of TCE was observed after 5 days of incubation. Uninoculated bioreactors inhibited with 0.5% Formalin and 0.2% sodium azide retained greater than 95% of their TCE after 20 days. Each bioreactor consisted of an expanded-bed column through which the liquid phase was recirculated and a gas recharge column which allowed direct headspace sampling. Pulses of TCE (20 mg/liter) were added to bioreactors, and gas chromatography was used to monitor TCE, propane, methane, and carbon dioxide. Pulsed feeding of methane and propane with air resulted in 1 mol of TCE degraded per 55 mol of substrate utilized. Perturbation studies revealed that pH shifts from 7.2 to 7.5 decreased TCE degradation by 85%. The bioreactors recovered to baseline activities within 1 day after the pH returned to neutrality

Cometabolic bioreactor demonstration at the Oak Ridge K-25 Site: Final report

The Oak Ridge National Laboratory (ORNL) conducted a demonstration of cometabolic technology for bioremediation of groundwater contaminated with trichloroethylene (TCE) and other chlorinated solvents. The technology demonstration was located at a seep from the K-1070-C/D Classified Burial Ground at the Oak Ridge K-25 Site. The technology demonstration was designed to evaluate the performance of two different types of cometabolic processes. In both cases, the TCE is cometabolized in the sense that utilization of a different primary substrate is necessary to obtain the simultaneous cometabolism of TCE. Trichloroethylene alone is unable to support growth and maintenance of the microorganisms. Methanotrophic (methane-utilizing) technology was demonstrated first; aromatic-utilizing microorganisms were demonstrated later. The demonstration was based on scaleup of laboratory and bench-scale prototype equipment that was used to establish the technical feasibility of the processes.This report documents the operation of the methanotrophic bioreactor system to treat the seep water at the demonstration site. The initial objectives were to demonstrate stable operation of the bioreactors and associated equipment, including the pretreatment and effluent polishing steps; and evaluate the biodegradation of TCE and other organics in the seep water for the three operating modes--air oxidation pretreatment, steam-stripping pretreatment, and no pretreatment