First Environment conducted a remediation of this chemical plant site which specialized in the manufacturing of specialty chemical products for the textile, paper products and graphic arts industries. Chlorinated organic compounds, including PCE, occurred in fractured bedrock and overlying weathered bedrock at the site. The geology made contamination migration routes difficult to predict and remediation a challenge; the facility’s ongoing operations added to this difficulty. First Environment approached the project by identifying potential risks and liabilities and addressing these risks in phases.
Due to the contamination, nearby residents were placed on city or bottled water, and First Environment delineated the groundwater contamination to determine the extent and identify potential sources. We implemented several remediation pilot systems including bio remediation and chemical oxidation. Specifically, the project team conducted detailed geophysical logging of four “open hole” crystalline bedrock wells utilizing gamma, spontaneous potential, resistivity, and caliper tests, as well as digital optical televiewer imaging to define dominant fracture trends. First Environment also installed and sampled 22 crystalline bedrock aquifer monitoring wells and installed 17 soil borings to collect soil samples at suspected potential chlorinated VOC source areas. Over the course of the project we collected and analyzed more than 2,000 soil and groundwater samples for VOCs, semi VOCs, metals and PCBs; we also oversaw the excavation of trenches to investigate magnetic anomalies potentially related to buried waste.
Remedial efforts involved implementing a combination of remedial technologies so as to intercept and halt the plume of organic contaminants in primary migration pathways and/or areas of higher risk of off-site migration. We also focused on stabilizing other locations to allow natural attenuation.
As a prelude to completing a Remedial Alternatives Analysis and Feasibility Study at the site, First Environment piloted two in situ groundwater cleanup technologies: enhanced in situ bio-remediation (EISB) and in situ chemical oxidation (ISCO). In situ methods were favored at the site due to the lack of suitable waste disposal options for ex situ treatment technologies and the limitations of the active facility. Both methods were found to be effective.
During the alternative evaluation, First Environment presented the ISCO technology as the preferred alternative since it was shown to be more cost effective. South Carolina DHEC approved the Final Feasibility Study in March 2007 and system design commenced immediately, with the Remedial Design Work Plan approved in early 2008. System construction was completed and started in October 2008. The system was immediately effective in reducing the chlorinated VOC plume concentrations by over 80 percent by early 2010. The system was expanded in 2010 to address areas of recalcitrant VOCs near the source area. While early results indicated the system expansion was successful, the site changed ownership, and the project was handed off to the owner’s consultant team in 2012. The system was expected to reach remediation objectives and be closed in 2013.