Optimization of In Situ Injection and Bioremediation Designat a Brownfield Site

摘要

The challenges associated with optimizing design, delivery and assessmentof in situ bioremediation are becoming more evident as the field matures. Radius ofinfluence and uniform distribution of amendment materials are critical parameters forcost-effective and timely design, implementation and assessment of in situ remedialactions. Enhanced in situ bioremediation was implemented at a chlorinated etheneimpactedBrownfield 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 areeither utilizing or proposing in situ bioremediation approaches.An innovative patented technology known as the Hornet Environmental Tool wasevaluated to assess the tool's ability of enhancing radius of influence and amendmentdistribution. A pilot-scale study was designed to compare the distribution of an emulsifiedoil substrate (EOS.) via conventional hydraulic injection versus enhanced injection withthe Hornet Environmental Tool. An electrical conductivity survey was implemented trackEOS. Distribution and the extent of influence. It was observed that zones where EOS.Was effectively distributed resulted in increased electrical conductivity presumably due tothe presence of sodium lactate, a component of EOS., which was considered a tracer forthe EC profiling. The Direct Image. EC System from Geoprobe. Was employed to assesspre-injection and post-injection electrical conductivity at defined radial distances fromthe respective injection points. Analysis of the EC data proved to be a valuable tool forthe assessment of the radius of influence, and the Hornet and conventional injectiontechniques.Full-scale biostimulation with EOS. Was completed based on the design parametersdefined in the pilot tests. This optimized injection scheme and design resulted in morethan 40% saving in remediation costs. Amendments were observed in treatmentmonitoring wells by visual observation, geochemical parameter measurements, and/orTOC analysis. Significant reductions in site contaminants were observed in post-injectionsampling events. Favorable geochemical conditions, presence of amendment, andreduction of contaminants coupled with the detection of Dehalococcoides further supportbiological reductive dechlorination at this site. The EOS. Treatment program resulted ingreater than 98% mass removal in the shallow source zone. Additionally, treatment in theupper zone has resulted in evident treatment of portions of the less-permeable lowerglacial till unit.