Former Paint and Pigments Plant
Slatington, Pennsylvania
Roux Associates was retained by a major paint and pigments manufacturer to manage all environmental assessment, remedial action and reporting activities at a former chromium hydrate and chromium oxide pigments manufacturing facility in Slatington, Pennsylvania. Remediation activities included the closure of lagoons, demolition of structures, excavation/disposal of soil from hot-spot areas, in situ treatment of hexavalent chromium via chemical reduction, and vegetative capping of the former lagoon and production areas. The remediation of this site was completed in cooperation with the Pennsylvania Department of Environmental Protection (PADEP), as part of its Voluntary Cleanup Program.
Roux Associates completed the project in three phases. The first phase included the performance of remedial investigation of overburden and bedrock groundwater, remedial design and construction oversight activities for the closure of four on-site wastewater treatment lagoons containing over 500,000 gallons of chrome-impacted wastewater associated with the chrome pigments operation. Roux Associates completed the work as a design/construct project on time and on budget.
The second phase of on-site remedial activities included preparation of contract specifications and drawings for construction of a 3.5-acre soil cap to provide dermal contact protection against residual chrome present in surface and subsurface soils at the site. Management and oversight responsibilities included: ensuring compliance with health and safety plan; installation of soil erosion and sedimentation controls; excavation and load-out of chrome impacted soil; demolition of site buildings and existing asphalt cap; site restoration; and installation of a vegetated cap.
In a third phase of work, Roux Associates conducted in situ treatment of a saturated soil and groundwater source area containing high concentrations of hexavalent chromium. This source area was located beneath the former location of the primary chemical reaction tanks. Roux Associates first conducted an options analysis to determine the most cost-effective treatment for this local source area. A number of chemical and biological in situ chromium reduction technologies were considered as well as more conventional technologies such as excavation and pumping/in situ flushing. Based on the results of bench scale testing, Roux Associates selected direct in situ chemical reduction via injection of sodium metabisulfite solution. The technical approach was reviewed and approved by both the PADEP and USEPA Region 3. An inexpensive field pilot test was conducted to establish potential reagent injection rates into the generally low-yielding formation. Remediation of the entire source area was then conducted, incorporating injection of sodium metabisulfite into a gallery of 18 injection points in a staged manner.
Roux Associates prepared a Remedial Action Report detailing site history, construction activities and analytical test results, and a Release of Liability was received for the site from PADEP for attainment of statewide health standards. The site is expected to be beneficially re-used for recreational purposes.