Automated ISCO Injection of EN Rx Reagent to Target Both Vadose Soil and Groundwater Contamination at a Bulk Oil Facility
Sultan Anjum, P.E., M.ASCE, D.WRE, Senior Engineer, Atlas
Difficult sites often require unique treatment approaches. This is the case at a Florida Bulk Oil Facility which had two challenging characteristics: vadose soil contamination and the groundwater plumes proximity to the four closed in place 10,000-gallon underground storage tanks (USTs) located under the above ground storage tank equipment storage building. These difficulties were overcome utilizing an automated injection system and a low concentration stabilized long-lasting oxidant. The remedial action plan (RAP) was designed to treat BTEX, MTBE, TRPH, Naphthalene’s and BAPs for vadose soil and groundwater impacts across the site. The in-situ chemical oxidation approach required a way to saturate the vadose zone continually and provide targeted groundwater zone treatment, to combat adsorption and back diffusion from less accessible soils around the USTs. Thus, the injections utilized a combination of EN Rx Reagent, a stabilized hydrogen peroxide, and an automated injection system known as FOCIS™ (Feedback Optimized Continuous Injection System). Utilizing a combination of vertical and horizontal trenched injection wells the system delivered 4000 lbs of oxidant per month. Baseline groundwater concentrations with the greatest impacts (approximately 18,000 ppb BTEX) were reported in monitor well MW-1. Over the course of the RAP implementation, areas of desorption were evident, and the longevity of oxidant was observed based on groundwater sampling field parameters. Laboratory analytical soil (September 21, 2021) and groundwater analytical results (May 19, 2022) indicate that no contaminants of concern exceeded any of their respective FDEP Soil Cleanup Target Levels SCTLs) and Groundwater Cleanup Target Levels (GCTLs). This includes the reduction of BAPs (to non-detect) in soil and a greater than 99.9% reduction of BTEX groundwater concentrations in MW-1. A review of the remedial design, implementation, performance, and analytical test results will be discussed in more detail as part of the presentation.
Mr. Anjum is a Senior Engineer in the Atlas Tampa, Florida office. His key responsibilities include performing soil and groundwater assessments, conduct pilot test studies; preparing Remedial Action Plans, SPCC Plans and SWPP Plans, and Stormwater Inspection and Permitting. Mr. Anjum areas of expertise include environmental consulting, geotechnical engineering and air quality management and is also involved in business development activities. He has been in the Environmental Industry for over 29 years.