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8751353 
Meetings & Symposia 
Optimization of in situ injection and bioremediation design at a Brownfield site 
Nichols Iii, HF; Lazar, BJ; Rabah, NM; Lippencott, RJ; Hicks, P; Carlson, B 
2009 
English 
The challenges associated with optimizing design, delivery and assessment of in situ bioremediation are becoming more evident as the field matures. Radius of influence and uniform distribution of amendment materials are critical parameters for cost-effective and timely design, implementation and assessment of in situ remedial actions. Enhanced in situ bioremediation was implemented at a chlorinated ethene-impacted Brownfield site in Passaic County, New Jersey. We report our strategy, design, and progress at this site, which should prove informative and useful to other sites that are either utilizing or proposing in situ bioremediation approaches. An innovative patented technology known as the Hornet Environmental Tool was evaluated to assess the tool's ability of enhancing radius of influence and amendment distribution. A pilot-scale study was designed to compare the distribution of an emulsified oil substrate (EOS®) via conventional hydraulic injection versus enhanced injection with the Hornet Environmental Tool. An electrical conductivity survey was implemented track EOS® distribution and the extent of influence. It was observed that zones where EOS® was effectively distributed resulted in increased electrical conductivity presumably due to the presence of sodium lactate, a component of EOS®, which was considered a tracer for the EC profiling. The Direct Image® EC System from Geoprobe® was employed to assess pre-injection and post-injection electrical conductivity at defined radial distances from the respective injection points. Analysis of the EC data proved to be a valuable tool for the assessment of the radius of influence, and the Hornet and conventional injection techniques. Full-scale biostimulation with EOS® was completed based on the design parameters defined in the pilot tests. This optimized injection scheme and design resulted in more than 40% saving in remediation costs. Amendments were observed in treatment monitoring wells by visual observation, geochemical parameter measurements, and/or TOC analysis. Significant reductions in site contaminants were observed in post-injection sampling events. Favorable geochemical conditions, presence of amendment, and reduction of contaminants coupled with the detection of Dehalococcoides further support biological reductive dechlorination at this site. The EOS® treatment program resulted in greater than 98% mass removal in the shallow source zone. Additionally, treatment in the upper zone has resulted in evident treatment of portions of the less-permeable lower glacial till unit.