Four T&M Abstracts Selected for Battelle’s Chlorinated Conference

March 31, 2022

T&M is proud to be selected to present three posters and one platform presentation at Battelle’s International Conference on Remediation of Chlorinated and Recalcitrant Compounds in Palm Springs, California.

Battelle’s Chlorinated Conference is recognized as the signature forum for the environmental remediation industry. The conference is the premier gathering of environmental professionals researching and applying innovative technologies and approaches for characterization, monitoring, cleanup and management of complex sites contaminated with the most challenging classes of chemicals.

Attendance is expected to be 1,500-1,700 environmental professionals from approximately 30 countries.

Summary of T&M Presentations at Battelle:

Evaluating Permeability and Treatment Enhancements to a Zerovalent Iron Permeable Reactive Barrier
Platform Presentation: Presented by Jim Peeples, T&M Associates

A zerovalent iron (ZVI) permeable reactive barrier (PRB) was installed to treat groundwater impacted with trichloroethene (TCE) and daughter products, with combined chlorinated ethenes (CE) concentrations in excess of 1.0 mM. Over the 15 years since installation, progressive permeability loss at the upgradient face of the PRB has been observed, leading to a 2- to 3-foot head differential across the front face. In-situ and ex-situ testing of front face samples failed to identify a clear, single cause for permeability loss; mineral precipitation, biomass accumulation and gas formation are potential contributing factors. Despite reduced groundwater flow through the PRB, partial groundwater treatment has continued to the present. The objective of the work described here was to test enhancements to the PRB that would allow long-term, effective treatment with the PRB.

Web-based Application for Recording Depth to Water Measurements in Monitoring Wells and Well Inspection Documentation
Poster Presentation: Presented by Scott Blanchard, T&M Associates

A groundwater plume of trichloroethene and daughter products, approximately one-half mile in length, was identified at an industrial facility (site). Remedial investigation, pilot testing, and remediation activities resulted in more than 600 groundwater monitoring, injection, pumping, and recovery wells being installed at the site. Potentiometric data collection events are extremely important at this site for understanding groundwater flow as it relates to individual source zones, overall plume geometry, and optimization of remedial alternatives. Quarterly potentiometric events are performed across the site using most of the wells in the network. A web-based application was created, allowing real-time tracking of the field event from the office. Water level data can be entered through voice or typed input, and the application can read back, after a time delay, the entered depth to water measurement for a measurement check. Entered values that are outside the range of historical data measurements at a well are flagged prompting the user to remeasure the well. Historic water elevation data, including time series plots of previously recorded values, can be accessed while at the well. The real-time upload of data from the application to the project directory ensures that data are not kept solely on the field tablet but are also archived on the company’s project servers as the monitoring event is occurring. The resultant savings in time for data capture, management, and use has elimination of three person-days for each event, while improving data quality.

High-Resolution Site Characterization of a Trichloroethene (TCE) DNAPL Source Zone with a Mobile Laboratory
Poster Presentation: Presented by Daniel Kekacs, T&M Associates

A release of trichloroethene (TCE) from underground piping at an industrial facility resulted in dense non-aqueous phase liquid (DNAPL) migration through surficial soils to a silty-sand aquifer and through the aquifer until the DNAPL reached an aquitard at approximately 60 feet below ground surface (bgs). The DNAPL TCE spread horizontally as it migrated to the aquitard, due in part to clayey sand lenses present in the silty-sand aquifer. The area of DNAPL spread was generally known based on the width of the dissolved-phase TCE groundwater plume that developed downgradient of the source area. However, the vertical and horizontal extents of the DNAPL source area could not be accurately determined from the downgradient plume or the limited number of borings and wells that had been installed within the source area/zone and estimates were needed for cost comparisons of potential remedial technologies.

A variety of high-resolution site characterization (HRSC) tools were considered to meet the objectives, and soil borings completed with Rotosonic drilling with sample analysis by EPA SW-846 Method 8265 by an on-site laboratory was selected. The soil borings were completed in a grid within the known source area, with soil samples obtained at 3-foot vertical intervals and continuous logging of the borings. The use of the onsite analytical method allowed for real-time decision making to minimize the number of borings while maximizing the data collected to support remedial alternative cost estimates, selection, and design. A large number of soil samples were processed per day (a maximum of 80 samples per day for this work) and the rapid return of data allowed real-time decision making in terms of expansion of the grid and sampling between grid points to provide a detailed delineation of the vertical and horizontal extents of DNAPL in this source zone.

Comparison of High-Resolution Site Characterization Tools for Evaluating Aquifer Characteristics and Extent of Contamination in Groundwater
Poster Presentation: Presented by Scott Blanchard, T&M Associates

A chlorinated ethene plume approximately one-half mile in length was identified at an industrial facility (site). A remedial investigation/ feasibility study (RI/FS) was conducted at the site, including soil borings and monitoring wells installed at discrete intervals. The initial remedial design and remedial actions relied on data collected during the RI, augmented with additional targeted investigations to support specific remedial design objectives. The resolution of the RI was not sufficient to support required additional remedial action and differentiation of comingled plumes at the site.

Three HRSC tools were used to refine the CSM and support remedy selection and design: (1) MiHPT borings coupled with a second direct push rig to conduct discrete interval soil and groundwater sampling; (2) Waterloo profiler borings installed in groundwater sampling fences; and (3) fences of shallow and deep temporary wells, fully screened across the sand intervals sampled in discrete intervals using an in-well packer system. The use of these HRSC tools at this site is compared and contrasted.