Pilot-Scale Demonstration of Surfactant-Enhanced PCE Solubilization at the Bachman Road Site. 1. Site Characterization and Test Design

Abstract

A pilot-scale demonstration of surfactant-enhanced aquifer remediation (SEAR) was conducted to recover dense nonaqueous phase liquid (DNAPL) tetrachloroethene (PCE) from a sandy glacial outwash aquifer underlying a former dry cleaning facility at the Bachman Road site in Oscoda, MI. Part one of this two-part paper describes site characterization efforts and a comprehensive approach to SEAR test design, effectively integrating laboratory and modeling studies. Aquifer coring and drive point sampling suggested the presence of PCE-DNAPL in a zone beneath an occupied building. A narrow PCE plume emanating from the vicinity of this building discharges into Lake Huron. The shallow unconfined aquifer, characterized by relatively homogeneous fine-medium sand deposits, an underlying clay layer, and the absence of significant PCE transformation products, was judged suitable for the demonstration of SEAR. Tween 80 was selected for application based upon its favorable solubilization performance in batch and two-dimensional sand tank treatability studies, biodegradation potential, and regulatory acceptance. Three-dimensional flow and transport models were employed to develop a robust design for surfactant delivery and recovery. Physical and fiscal constraints led to an unusual hydraulic design, in which surfactant was flushed across the regional groundwater gradient, facilitating the delivery of concentrations of Tween 80 exceeding 1% (wt) throughout the treatment zone. The potential influence of small-scale heterogeneity on PCE-DNAPL distribution and SEAR performance was assessed through numerical simulations incorporating geostatistical permeability fields based upon available core data. For the examined conditions simulated PCE recoveries ranged from 94to 99%. The effluent treatment system design consisted of low-profile air strippers coupled with carbon adsorption to trap off-gas PCE and discharge of treated aqueous effluent to a local wastewater treatment plant. The systematic and comprehensive design methodology described herein may serve as a template for application at other DNAPL sites.

Surfactant-enhanced remediation of organic contaminated soil and water

“…Although there are many laboratory scale studies are available but there are only a limited field studies are available on SER [45,104,[274][275][276][277][278]. Mostly the field studies are in-situ [104,[274][275][276][277][278] rather than ex-situ [45].…”

“…Mostly the field studies are in-situ [104,[274][275][276][277][278] rather than ex-situ [45]. Lee et al [278] have reported surfactant enhanced pilot-scale in-situ flushing of nonionic surfactant sorbitan monooleate (POE 20) to remediate the site contaminated with diesel, kerosene, and lubricating oil at Pusan, Korea.…”

Simulation of the subsurface mobility of carbon nanoparticles at the field scale

“…In this study the mobility of carbon based nanoparticles is investigated using aquifer statistics derived from a field site in Oscoda, MI [21,22,31,33,1,7]. The field site is comprised of relatively homogeneous glacial outwash sands 8 m in depth and is underlain by a thick clay layer.…”

“…Twelve vertical and directional cores were obtained and divided into 167 subsamples for further grain size distribution and hydraulic conductivity analysis. This information was then used to develop 16 non-uniform permeability fields using conditional sequential Gaussian simulation (SGS) [21,22,33,1,7]. With the exception of the homogeneous case simulation, the mobility of the carbon based nanoparticles was assessed using all 16 permeability fields for all cases presented.…”

Retention of Nanoparticles: From Laboratory Cores to Outcrop Scale

“…For example, the values of retention constants (irreversible and reversible) and the desorption constant in a two-site model obtained by history matching several coreflood effluent concentration data by Zhang [19] are in the range of 10 −2 -10 −4 1/s. However, using these parameter values to perform a field scale simulation would suggest complete retention of NPs in the pore space, which is physically inconsistent with the observations in a pilot-scale injection of NPs [36,[63][64][65][66][67]. As mentioned earlier, there is no theoretical or empirical basis that could be used to estimate these parameters; however, we can use an analogous relationship for the deposition rate constant from colloid filtration theory that has been rigorously tested and applied to model NP retention [19,39,68,69].…”