Highvacuum Soil Vapor Extraction System

In September 1994, the NMSHTD retained a second consultant, Daniel B. Stephens & Associates, Inc. (DBS& A) to design and implement a corrective action system at the Artesia Patrol Yard. Sections 3.1 and 3.2 outline DBS& A's rationale for and design of the high-vacuum SVE system for the Artesia Yard. The techniques used to enhance the recovery of petroleum vapors from the vadose zone are described in Sections 3.3 and 3.4. These techniques extended the operation of the high-vacuum SVE...

Air Pressure

Unsaturated-zone air pressure and temperature were measured using four unvented Geokon, Inc. model 4500LP vibrating-wire pressure transducers with a range of 0-10 psi (0-70,000 N m2). All the transducers are accurate to 0.1 of full scale, corresponding to 0.01 psi for the model 4500LP. Measurements were collected at several depths ranging from 0.33 m to 1.68 m (Table 1). The transducers were attached to standard AW-threaded drill rods and installed at the bottom of separate 7-cm diameter...

Experimental Methods

Detailed experimental procedures have been previously reported (Ko, 1998 Ko et al., 1998a,b) therefore, they are only briefly described here. Phenanthrene (Aldrich, 99.5+ ), naphthalene (Aldrich, 99+ ), SDS (Sigma, 99.5+ ), and Tween 80 (Aldrich, no purity reported) were used as received selected physicochemical properties for these compounds are shown in Table 1. Kaolinite, a nonswelling 1 1 layer phyllosilicate clay and common constituent of many subsurface environments, was used as received...

Previous Research On Barometric Pumping

Atmospheric pressure near land surface is constantly changing, due both to short-term diurnal temperature and gravitational fluctuations as well as longer-term cycles due to the passage of high-and-low pressure weather systems (Figure 1). Analysis of data taken by the National Oceanographic and Atmospheric Administration (NOAA) in 1998 at the Newark International Airport in Newark, NJ show pressure fluctuations that vary from the mean by 250 N m2 (2.5 mbar) during 73 of the observations, with...

Electrochemical and Biogeochemical Interactions under dc Electric Fields

ALSHAWABKEH1 and KRISHNANAND MAILLACHERUVU2 'Department of Civil and Environmental Engineering, Northeastern University, Boston, MA 2Department of Civil Engineering and Construction, Bradley University, Peoria, IL 61625 Key words electrostimulation, electrokinetic, electrochemical, bioremediation Abstract Direct electric currents generate electrochemical and biochemical changes that impact the subsurface environment and can be engineered for transporting and mixing contaminants,...

TCE and Chemical Analysis

In order to determine the initial TCE concentrations prior to initiation of EO, samples of the contaminated slurry were collected at the same time they were loaded into individual EC. A 5 g slurry sample was loaded into a previously weighed, teflon-capped borosilicate vial. After reweighing to obtain the actual sample weight, the vial was opened and reagent grade methanol added to the top of the vial and the teflon cap replaced without headspace in the vial. The vial was again re-weighed to...

Pilot Test of a Surfactant Modified Zeolite Permeable Barrier for Groundwater Remediation

Pilot Test Sve Diagram

BOWMAN1, ZHAOHUI LI1, STEPHEN J. ROY1, TODD BURT1, TIMOTHY L. JOHNSON2, and RICHARD L. JOHNSON2 'Department of Earth and Environmental Science, New Mexico Institute of Mining and Technology, Socorro, NM 87801 2Department ofEnvironmental Science and Engineering, Oregon Graduate Institute of Science and Technology, Beaverton, OR 97006 Key words chromate, perchloroethylene, sorption, transport Abstract Two pilot-scale tests of surfactant-modified zeolite (SMZ) permeable barriers were...

Bibliography

B. and Alshawabkeh, A. (1993) Principles of Electrokinetic Remediation, Environmental Science and & Technology, 27(13), pp. 2638-2647. Acar Y. B. and Alshawabkeh A. (1996) Electrokinetic Remediation I. Pilot-scale Tests with Lead Spiked Kaolinite, Journal of Geotechnical Engineering, ASCE, 122(3), pp. 173185. Acar, Y. B., Li, H., and Gale, R. J. (1992). Phenol Removal from Kaolinite by Electrokinetics, Journal of Geotechnical Engineering, ASCE, 118(11), pp. 1837-1852. Acar, Y. B.,...

Electroosmosis Cell EC

Electroosmosis soil column is a 29 cm long acrylic tubes (5.8 cm i.d.) with tight fitting screw caps at the top. Each column contained 18 cm of undisturbed soil core. All ECs were assembled as shown in Figure 1. Adsorption of TCE to the surface of column was checked at a concentration used in the experiments and was found non-detect (< 0.10 g g). A total of thirteen ECs were prepared. Four ECs were used as controls, i.e., no electrical current was applied. One column was designed so that...

Surfactant Gradient Effects

To understand the effects that surfactants have on the gradient driving the desorption of hydrophobic organic contaminants in soil water systems, it is necessary to know how surfactant molecules distribute themselves among the different portions of the soil and the aqueous phase. Surfactant molecules may sorb to the different fractions of the soil. For example, surfactant molecules may sorb to and form aggregates at a soil's mineral surface. In addition, a fraction of the sorbed surfactant is...

Chemical Analyses

Samples from the 40-mL VOA vials were split for chromate and PCE analyses and typically analyzed within 48 hours of collection. Chromate concentration was determined via an HPLC method using a Gilson Model 116 UV detector set at 365 nm and a 2- by 150-mm Waters Nova-Pak CI8 60A HPLC column packed with 4- m particles. The mobile phase consisted of 5-mM tert-butylammonium hydrogen sulfate buffered to pH 4.4 with NaOH with 10 acetonitrile (v v) as a modifier. The eluent flow rate was 0.8 mL min-1...

Determining Eacn Of Unknown Napls

Having stated that NAPL EACN (hydrophobicity) is critical to designing successful surfactant systems, a method is needed to determine the EACN of hydrophobic NAPLs. The EACN concept was introduced by Wade and Schecter and co-workers in the 1970s for understanding and correlating surfactants for enhanced oil recovery (Salager et. al. 1979, Bourrel and Schecter 1988) and later found to be of great value in understanding and evaluating surfactant enhanced subsurface remediation of chlorocarbons...

Phase Behavior

Hydrophilic PCE (EACN 2.9) was mixed with an equal volume of the hydrophilic surfactant system Aerosol-MA, isopropyl alcohol, and NaCl (AMA IPA NaCl) (Figure 3). With increasing salinity, a classical Winsor phase progression was observed from type I to type II, with type III in-between. When this same surfactant system was applied to dodecane, with an EACN of 12, the classical Winsor type I< > III< > II phase progression did not occur, and while a middle phase was achieved (data not...

CFSTR Methodology

A continuous-flow stirred tank reactor (CFSTR) apparatus was used to study the effect of several surfactants on the kinetic desorption of TCE from soil to water (Deitsch and Smith 1995). Individual CFSTRs consisted of a cylindrical glass reactor (1.0 cm i.d. X 15 cm) with Teflon end fittings and stainless-steel screens. The fittings were secured and formed airtight seals at the ends of the glass reactor. Omnifit two-way valves were connected to the inflow and outflow fittings of the CFSTR with...

Conclusions

Reductive dechlorination of chlorinated solvents in the ZVI system is a surface-mediated process. Adsorption of the chlorinated compounds takes place prior to the reduction, but the overall rate of reduction is limited by the electron transfer from the surface to the chlorinated compounds. The adsorption can occur on either reactive or nonreactive sites, while the reduction rate is directly proportional to the amount adsorbed onto the reactive sites. The proportion adsorbed onto reactive sites...

Contributors

Ahlfeld University of Massachusetts Amherst, MA Aysegul Aksoy University of Virginia Charlottesville, VA Akram N. Alshawabkeh Northeastern University Boston, MA New Mexico Institute of Mining amp New Mexico Institute of Mining amp Jeffrey D. Childs University of Oklahoma Norman, OK Jee-Won Choi University of Virginia Charlottesville, VA Teresa B. Culver University of Virginia Charlottesville, VA University of Kentucky Lexington, KY Kirn F. Hayes University of Michigan Ann Arbor, MI...