First Environment is supporting Route 21 Associates by investigating and remediating very high levels of chlorinated organic compounds within the overburden and bedrock aquifer systems both on- and off-site for the redevelopment of the former Walter Kidde site. The site is being addressed under a Brownfields agreement with the New Jersey Department of Environmental Protection (NJDEP). It was initially constructed and utilized by the Defense Plant Corporation in 1940 to manufacture fire-extinguishing systems and other goods needed for the World War II war effort. In 1947 the Defense Plant Corporation sold the property to Walter Kidde & Company.
Site Scoping, Characterization and Preliminary Assessment
To gain a thorough understanding of prior site operations which led to the contamination at the site, as well as the local and regional geologic framework, First Environment performed detailed initial site characterization activities that began with a comprehensive review of available documents and preliminary assessment of site-specific manufacturing activities as well as the development of a Conceptual Site Model (CSM). Based on our review of state and local records, it became apparent that details of the historical operations at the site were poorly documented and there were no detailed project files from the Defense Plant Corporation or Water Kidde regarding past operations. Accordingly, we completed project scoping activities and developed comprehensive site and remedial investigation work plans to accurately characterize the subsurface in terms of chlorinated organic compounds migration, fate and transport both in soil and groundwater.
First Environment installed numerous soil borings and collected samples for laboratory analyses to evaluate potential source areas for the contamination. The results revealed the prior degreasing operations were the primary contributor to the identified impacts. To fully characterize the horizontal and vertical extent of impacted groundwater, nested monitoring wells including shallow overburden, deep overburden, shallow bedrock and deep bedrock were installed to complete the horizontal and vertical delineation of contaminants both on- and off-site. We used packer testing to delineate the vertical extent of impact within the bedrock aquifer. The packer test results revealed impacts that extended to depth of over 400 feet. Groundwater both on- and off-site had been impacted with significant levels (>50,000 parts per billion) of chlorinated organic compounds. First Environment characterized and remediated soil at the site so that No Further Action was required with respect to site soil.
Based on the fact that the site is being remediated pursuant to a Brownfields agreement and the Township was an interested party to the matter, First Environment has attended public and town hall meetings to address the status of the remediation and overall site redevelopment. We also interfaced with town officials and redevelopers as well as other interested stakeholders to bring the site back to productive use.
Given the levels of contamination identified and the potential for vapor intrusion (VI) impacts, First Environment performed a thorough evaluation of VI issues to determine if the VI pathway was complete and whether potential receptors were at risk. As part of the investigative phase, we conducted VI testing to assess potential impacts to nearby residential and commercial structures. To complete this evaluation, we collected and analyzed near slab, sub slab and indoor air samples for TO-15 parameters in accordance with VI guidance protocols. Based on the results of the indoor air sampling, no additional VI work was required given the results of the testing and background inventories.
Evaluation of Remedial Alternatives
Once groundwater was fully characterized, First Environment conducted a thorough evaluation of remedial alternatives. The evaluation took into account the remedial action objectives, ability to implement, short and long term effectiveness, protection of human health and the environment, potential migration pathways, potential impacts to receptors, the site specific geologic framework, and the implementation costs. The alternatives screened included: dual phase extraction, air sparging/soil vapor extraction, groundwater recovery and treatment, in-situ chemical oxidation using activated persulfate, enhanced bio-augmentation using KB-1 Plus culture and thermal remediation. Based on the screening of remedial alternatives, First Environment selected dual phase extraction and enhanced bio-augmentation for further evaluation. We conducted this evaluation through the completion of treatability tests to further determine the efficacy and costs of each alternative.
Subsequent to the remedial alternative screening process, First Environment completed treatability studies for the dual phase extraction as well as enhanced bio-augmentation remedies to further evaluate these technologies. The study for the dual phase alternative included the installation of specifically designed extraction wells and the performance of an in-field pilot test using a high vacuum pump. The pilot testing results revealed the overburden aquifer yielded very little water whereas the deep overburden yielded substantial volumes, which precluded the use of this technology. The treatability testing of the enhanced bio-augmentation alternative included microcosm testing to determine whether or not the selected culture could achieve the RAOs. The results of the microcosm testing yielded favorable reductions of chlorinated compounds. Accordingly, First Environment implemented in-field pilot testing using emulsified soybean oil as an electron donor and KB-1 Plus culture as the microbial amendment. KB-1 Plus consists of a blend of dehalococcoides and dehalobacter strains which are capable of reducing chlorinated organics including 1,1,1-TCA. The results of the in-field pilot test revealed a greater than 80 percent reduction of chlorinated organic compounds from the pre-injection baseline.
Remedial Action Work Plan Development and Full Scale Implementation
Given the results, First Environment developed a comprehensive Remedial Action Work Plan, which subsequently received NJDEP approval. With the receipt of approval, we completed a full scale remedial design to effectively treat the approximately 150-foot by 300-foot source area. We also worked with the regulatory authority to obtain the necessary permits for a discharge to groundwater application of microbes and donor. We are currently proceeding with the full scale application of electron donor and KB-1 Plus culture.