Zero Valent Iron Activated Persulfate Oxidation of Trichloroethylene
Chenju Liang, D.Eng., Dept. of Environmental Engineering, National Chung Hsing University
Ming-Chun Lai, Dept. of Environmental Engineering, National Chung Hsing University

Fenton-like Oxidation of Pentachlorophenol in Iron-Rich Sandy Soil at Neutral pH
Student Presenter
Roger J. Matta, Laboratoire Chimie Provence
Serge Chiron, Laboratoire Chimie Provence
Khalil Hanna, Laboratoire de Chimie Physique et Microbiologie pour l’Environnement

Ex-Situ ChemOX Remediation of Petroleum Contaminated Soils
Richard T. Cartwright, MECX LP SDVOSB
Isaac M. Aboulafia, MECX LP SDVOSB

Combining Chemical Oxidation with Aerobic Bioremediation – A Dual Prong Approach
Philip A. Block, PhD, FMC Corporation

Comparison of ISCO and Bio Technologies for Reduction of TCE for Source and Plume Management
Ian T. Osgerby, PhD PE, USACE
Duane Root, PhD, Shaw Environmental Inc.
Douglas Jerger, PhD, Shaw Environmental Inc.

Zero Valent Iron Activated Persulfate Oxidation of Trichloroethylene
Chenju Liang, D.Eng., Dept. of Environmental Engineering, National Chung Hsing University, 250 Kuo-Kuang Rd., Taichung, Taiwan, Tel: 886-4-22856610, Fax: 886-4-22862587, Email: Cliang@dragon.nchu.edu.tw
Ming-Chun Lai, Dept. of Environmental Engineering, National Chung Hsing University, 250 Kuo-Kuang Rd., Taichung,  Taiwan, Email: miko910417kimo@hotmail.com

The present study describes the use of zero valent iron (Fe⁰) as a source for ferrous ion activated persulfate (PS) oxidation of trichloroethylene (TCE).  The experimental results indicated that in the absence of TCE there was a lag time for persulfate decomposition when the reaction was activated by Fe⁰.  An initial pH drop in the Fe⁰/PS system to acidic conditions was accompanied by the persulfate decomposition and a decrease in oxidation-reduction potential (ORP) values.  Furthermore, in the TCE/Fe⁰/PS system, the rapid TCE degradation was accompanied by the rapid persulfate decomposition and chloride ion formation as evidence of TCE mineralization.  SEM images of Fe⁰ before and after persulfate oxidation exhibited significant corrosions of Fe⁰.  Acicular aggregate formation in the absence of TCE and coarse aggregate formation in the presence of TCE were observed.  Moreover, the XRD spectrum revealed the formation of magnetite over the surface of Fe⁰ after contact with persulfate.  Thus, Fe⁰ activated persulfate oxidation offers a fast and effective way for remediation of TCE contamination.

Fenton-like Oxidation of Pentachlorophenol in Iron-Rich Sandy Soil at Neutral pH
Student Presenter
Roger J. Matta, Laboratoire Chimie Provence UMR6264, Place Victor Hugo 13331 Marseille cedex 3, France , Tel: (33) 066786575, E-mail: roger_matta@hotmail.com
Serge Chiron, Laboratoire Chimie Provence UMR6264, Place Victor Hugo 13331 Marseille cedex 3, France , Tel: (33) 0491108525, E-mail: serge.Chiron@univ-provence.fr
Khalil Hanna, Laboratoire de Chimie Physique et Microbiologie pour l’Environnement UMR7564 405, rue de Vandoeuvre, F-54600 Villers-les Nancy , France , Tel: (33) 03 83685242, Fax: (33) 03 83275444, E-mail: khalil.hanna@lcpme.cnrs-nancy.fr

Pentachlorophenol (PCP) is a widespread environmental contaminant due to its use as a pesticide for wood preservation. PCP contamination can be found in surface, ground waters and in soils, in the vicinities of past wood-treating facilities and is classified in the priority list of the organic pollutants by the U.S. Environmental Protection Agency.

Heterogeneous Fenton reaction (hydrogen peroxide/iron minerals) can effectively oxidize contaminants at circumneutral pH, which could be a promising technology for the application of the in situ chemical oxidation (ISCO) of contaminated soils and groundwaters.

In this study, the adsorption and oxidation of pentachlorophenol (PCP) in iron-rich sandy soil system have been investigated under static and dynamic conditions. Iron-bearing materials were synthesized and characterized by XRD, Mössbauer spectroscopy, BET surface area, particle size and chemical analyses. Batch and leaching column experiments were performed to evaluate the concentration evolution of H2O2, pollutant, dissolved iron, total organic carbon over contact time, and to determine the major oxidation by-products. The kinetic of oxidation by Fenton-like process was studied under various H2O2/Fe ratios and correlated with the adsorption behavior in the dark at neutral pH. Fourier transform infrared spectroscopic (FTIR) analysis showed that the electrostatic effects between ionizable organic compounds and surface functional groups of oxide surface play a role in determining the oxidation rate of organic compounds in mineral oxide/H2O2 system. Other parameters such as material’s iron content, iron oxidation state, specific surface area, H2O2/Fe ratio showed to be key parameters in the oxidation of the pollutant.  A model of surface oxidation by Fe is presented in which degradation of pollutant at the surface is proposed. This study allowed us to better understand the kinetic of adsorption/oxidation in heterogeneous Fenton reaction, which may be considered to be a promising way of remediation of contaminated soils and groundwater.

Ex-Situ ChemOX Remediation of Petroleum Contaminated Soils
Richard T. Cartwright, MECX LP SDVOSB, 8096 Clarherst Drive, East Amherst , NY 14051 , USA , Tel: 713-412-9697, Fax: 713-585-7049, Email: Richard.Cartwright@mecx.net
Isaac M. Aboulafia, MECX LP SDVOSB, 3203 Audley Street, Houston , Texas   77098 , USA , Tel: 713-585-7008, Fax: 713-585-7049, Email: isaac.aboulafia@mecx.net

Innovative ex-situ soil and sediment treatment process has successfully been applied to safely and economically reduce total contaminant mass of petroleum hydrocarbon in saturated silty clay soil at a Brownfield Redevelopment Site. This process incorporates a sequential dry chemical application program in treatment cells to allow full distribution of chemical oxidation chemicals prior to soil hydration. This process uses controlled exothermic oxidation reactions to effectively oxidize contaminants in the dissolved phase.

Treatment process presented is an enhancement of the proven Activated Sodium Persulfate (ASP) and Catalyzed Hydrogen Peroxide (CHP) processes. This treatment train process has been successfully implemented at several non-aqueous phase liquid (NAPL) sites. Using this approach, the properties of each oxidant are optimized. CHP oxidation properties are optimized to effectively desorb mass from the soil while dissolving NAPL mass. The sodium persulfate process is optimized by persistence in oxidizing dissolved mass.

This dry chemical process uses the combination of sodium percarbonate (PCS) and sodium persulfate at an elevated pH with an iron catalyst. The exothermic CHP generated by the hydration of the sodium percarbonate and surfactant effect of the high pH reaction enhances desorption of the contaminant allowing for very efficient and effective oxidation.

A case history will be presented describing the use of this treatment train approach whereby using preferential chemical distribution with an innovative and environmentally friendly oxidation program which is designed to provide for effective and efficient dissolution and desorption of the high concentration hydrocarbons will indeed achieve sufficient contaminant reductions to allow for on-site disposal and/or soil reuse. 

Combining Chemical Oxidation with Aerobic Bioremediation – A Dual Prong Approach
Philip A. Block, PhD, FMC Corporation, 1735 Market St, Philadelphia, PA  19103, USA,  Tel: 215-299-6645, Email: philip.block@fmc.com

There is no silver bullet technology that is guaranteed to remediate every contaminated site to MCL targets.  It has been increasing recognized that combining different remediation approaches for treatment greatly increases the probability of success in achieving site clean-up goals.  Over the past several years, activated persulfate has been demonstrated as a viable in situ chemical oxidation technology to treat a broad range of recalcitrant compounds, particularly in source and hot spot zones.  However, at site where NAPL may be present or there is significant heterogeneity in the subsurface, multiple applications must be employed to address issues of rebound and desorbtion-rate limited contamination.  In addition, chemical oxidation may be cost prohibitive in treating down range, diffuse contaminant plumes.  Coupling persulfate chemical oxidation to bioremediation allows for a strong, oxidative treatment of source zones in conjunction with a longer term bioremediation stage that can serve as a polishing step and subsequent treatment of down gradient contamination.  A new product that couples persulfate and a slow release oxygen source will be discussed, and its impact will be demonstrated via a field pilot at a site in Canada contaminated with BTEX and fuel constituents.  Contaminant destruction efficacy and impact on the biological population will be discussed.

Comparison of ISCO and Bio Technologies for Reduction of TCE for Source and Plume Management
Ian T. Osgerby, PhD PE, USACE, 696 Virginia Rd. Concord , MA 01742 , Tel: 978-318-8631, Fax: 978-318-8614, Email: ian.t.osgerby@usace.army.mil
Duane Root, PhD, Shaw Environmental Inc., Technology Development Laboratory, 304 Directors Dr. , Knoxville , TN 37923 , Tel: 865-694-7360, Fax: 865-694-9573, Email: Duane.Root@shawgrp.com
Douglas Jerger, PhD, Shaw Environmental Inc., Technology Development Laboratory, 304 Directors Dr. , Knoxville , TN 37923 , Tel: 865-694-7360, Fax: 865-694-9573, Email: Douglas.Jerger@shawgrp.com

A technology evaluation study was carried out in a series of bench tests at Shaw Environmental Laboratories in Knoxville , TN.   The studies were oriented at proposed remediation of a source area and a down gradient plume.  The site is a FUDS site, the former Raritan Arsenal, located in Middlesex County , New Jersey , on the banks of the Raritan River , approximately 20 miles southwest of Lower Manhattan and proximate to Edison/Woodbridge NJ.  It is bordered to the north and west by Woodbridge Ave. and to the southwest by Mill Rd. and the Industrial land Reclamation Landfill.  It was used by the U.S. Army from 1917 to 1963.

The technologies evaluated comprised two ISCO variants: permanganate and persulfate and comprised acid demand, SOD studies and contaminant destruction efficiency, and two microbial variants comprising an evaluation of bio-stimulation and bio-augmentation, and a co-metabolic study using methane and propane.

The bench studies determined that SOD was too high for cost effective ISCO in the source area but that ISCO was preferable in the plume location where the SOD was unusually low, favoring a permanganate application.  The biostimulation was ineffective but combined with bioaugmentation using Shaw’s home-brewed SDC-9 dehalogenation culture was very effective in achieving contaminant elimination.  Both plume and source applications were successful in eliminating the chlorinated solvents although sequenced daughter product results were inconclusive.  Molar balancing with ethane as the end product with satisfactory intermediate compounds was not demonstrated.  No stalling was experienced with the bioaugmented option.

The results are presented and the selection process/conclusions outlined with recommendations for pilot testing to be carried out later this year.