SPECIAL REPORT 97-18

Site Remediation via Dispersion by

Chemical Reaction (DCR)

Giles M. Marion, James R. Payne, and Gurdarshan S. Brar August 1997
Abstract: The DCR (Dispersion by Chemical Reaction) technologies are a group of patented waste treatment processes using CaO (quicklime) for the immobilization of heavily oiled sludges, oil-contaminated

soils, acid-tars, and heavy metals in Ca(OH)2 and

CaCO3 matrices. The objectives of this project were to

1) evaluate the DCR process for remediating soils

contaminated with pesticides, petroleum hydrocarbons (oils and fuels), and heavy metals in cold

regions and 2) evaluate DCR-treated oil-contaminated soil as a non-frost-susceptible (NFS) construction

material. Three major studies evaluated the DCR process to remediate 1) hydrocarbons at Eareckson Air

Force Station on Shemya in the Aleutians, 2) pestiHow to get copies of CRREL technical publications:

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cide-contaminated soils from Rocky Mt. Arsenal, and

3) heavy-metal contaminated soils from a former zinc

smelter site at Palmerton, Pennsylvania. The DCR process was successful in stabilizing liquid organics and

heavy metals in contaminated soils. The chemical

properties of soils contaminated by solid organics

(asphalt tar and pesticides) were not generally improved by the DCR process, but even in these cases,

the physical properties were improved for potential

reuse as construction materials. Following laboratory

verification for a specific waste, we can recommend

the DCR process for the field remediation of liquid

organics and heavy-metal-contaminated materials.
Special Report 97-18

Site Remediation via Dispersion by

Chemical Reaction (DCR)

Giles M. Marion, James R. Payne, and Gurdarshan S. Brar August 1997

Prepared for

OFFICE OF THE CHIEF OF ENGINEERS

Approved for public release; distribution is unlimited.

US Army Corps

of Engineers®

Cold Regions Research &

Engineering Laboratory
PREFACE

This report was prepared by Dr. Giles M. Marion, Research Physical Scientist,

Geochemical Sciences Division, Research and Engineering Directorate, U.S. Army Cold

Regions Research and Engineering Laboratory; James R. Payne of SOUND/Epic (formerly Sound Environmental Services); and Dr. Gurdarshan S. Brar, formerly of CRREL.

This work was funded through U.S. Army Corps of Engineers CPAR (Construction Productivity Advancement Research) Project AC910260, Site Remediation via Dispersion by

Chemical Reaction (DCR), to evaluate DCR technologies for handling different types of

contaminants at DOD facilities.

The authors thank Dr. Paul Miyares and Dr. Mike Reynolds for technically reviewing

this manuscript, and Jeffrey Bauman, John Bayliss, Tim Cary, Edward Cronick, Steven

Fitzhugh, Debra Pelton, Michael Stanka, and Patricia Striebich for assistance with field,

greenhouse, and laboratory analyses.

The contents of this report are not to be used for advertising or promotional purposes.

Citation of brand names does not constitute an official endorsement or approval of the

use of such commercial products.

ii
iii

CONTENTS

Preface ........................................................................................................................................... ii

Executive Summary .................................................................................................................... v

Introduction.................................................................................................................................. 1

Lime-based technologies ....................................................................................................... 1

DCR technologies ................................................................................................................... 3

Methods and materials ............................................................................................................... 3

Shemya study .......................................................................................................................... 3

Rocky Mt. Arsenal study ....................................................................................................... 5

Palmerton zinc smelter study ............................................................................................... 7

Results and discussion ............................................................................................................... 8

Shemya study .......................................................................................................................... 8

Rocky Mt. Arsenal study ....................................................................................................... 12

Palmerton zinc smelter study ............................................................................................... 13

Conclusions .................................................................................................................................. 17

Recommendations ....................................................................................................................... 19

Commercialization/Technology transfer ................................................................................ 19

List of presentations, publications, and videos ...................................................................... 18

Literature cited ............................................................................................................................. 19

Abstract ......................................................................................................................................... 21

ILLUSTRATIONS

Figure

1. Transportable treatment unit used on the Shemya study ............................................. 4

2. Water content of untreated soil-asphalt tar and laboratory and field DCR-treated

material ........................................................................................................................... 8

3. Changes in air, stockpiled, untreated, and DCR-treated material temperatures ...... 9

4. Leachate pH as affected by soil treatment, plant species, and time ............................ 15

5. Leachate Zn concentration as affected by soil treatment, plant species, and

time .................................................................................................................................. 16

6. Plant biomass/tube as affected by soil treatment and plant species ........................... 17

7. Plant Zn concentrations as affected by soil treatment and plant species ................... 18

8. Plant Zn contents/tube as affected by soil treatment and plant species .................... 19

TABLES

Table

1. Characteristics of major lime, limestone products, and by-products used in waste

treatment ........................................................................................................................ 1

2. Descriptive chemical characterization of RMS Basin F liquid ...................................... 6

3. Changes in hydraulic conductivity after one freeze–thaw cycle ................................. 8

4. Total extractable concentrations of TPH and volatile organics in asphalt–tar

samples ........................................................................................................................... 9
iv

Table

5. Total extractable concentrations of TPH and volatile organics in TCLP extracts

of asphalt–tar samples.................................................................................................. 10

6. Total extractable concentrations of TPH and BTEX constituents in organiccontaminated soils ........................................................................................................ 11

7. Total extractable concentrations of TPH and BTEX constituents in TCLP extracts

of organic-contaminated soils ..................................................................................... 11

8. Summary of selected constituent analyses of RMA Basin F soil sample no. 24216

at different levels of DCR reagent addition with and without compaction ........ 12

9. Summary of TCLP leachable constituent analyses on RMA Basin F soil sample

no. 24216 before and after DCR treatment ................................................................ 13

10. A summary of the soil analyses for the Palmerton zinc smelter study ....................... 14
v

EXECUTIVE SUMMARY

The DCR (Dispersion by Chemical Reaction)

technologies are a group of patented waste treatment processes using CaO (quicklime) for the immobilization of heavily oiled sludges, oil-contaminated soils, acid-tars, and heavy metals in

Ca(OH)2 and CaCO3 matrices. The objectives of

this project were to 1) evaluate the DCR process

for remediating soils contaminated with pesticides, petroleum hydrocarbons (oils and fuels),

and heavy metals in cold regions and 2) evaluate

DCR-treated oil-contaminated soil as a non-frostsusceptible (NFS) construction material. Three

major studies evaluated the DCR process to remediate 1) hydrocarbons at Eareckson Air Force Station on Shemya in the Aleutians, 2) pesticide-contaminated soils from Rocky Mt. Arsenal, and 3)

heavy-metal contaminated soils from a former

zinc smelter site at Palmerton, Pennsylvania.

The DCR process was originally developed for

the immobilization of liquid hydrocarbons. The

laboratory-scale tests on Shemya wastes were a

test of the efficacy of the DCR process to immobilize liquid hydrocarbons. The DCR process caused

a major decrease in TCLP-extractable hydrocarbons. Both volatilization and Ca(OH)2 encapsulation may have played a role in the disappearance

of these organic constituents. The results were,

however, not consistent between wastes, indicating that the specific nature of the wastes will play

a major role in the efficacy of the DCR process to

remediate the wastes.

We also examined two organic wastes that were

solids at the prevailing temperature. One was the

asphalt tar from Shemya, and the other was the

pesticides from Rocky Mt. Arsenal. In neither case

was there a significant overall improvement in

chemical properties due to the DCR treatment.

It would appear that unless the hydrophobic CaO

can readily disperse into the organic phase,

the DCR process is not effective immobilizing

organics.

On the other hand, the DCR process is strongly

dehydrating. Application of the DCR process to

the solid asphalt tar from Shemya produced a

drier, more soil-like, material with hydrophobic

properties. This would improve the physical

properties for potential reuse as road subgrade or

landfill covers.

The DCR treatment greatly reduced the mobility of Zn through greenhouse soil columns. Neutralization of acidity, and adsorption onto and precipitation as hydroxides and carbonates probably

were responsible for reduced Zn mobility. Judging

by the Zn concentrations in plant tissue and biomass production, the DCR treatment improved

plant growth in the Zn-contaminated soil.

The DCR process was successful in stabilizing

liquid organics and heavy metals in contaminated

soils. The chemical properties of soils contaminated by solid organics (asphalt tar and pesticides)

were not generally improved by the DCR process,

but even in these cases, the physical properties

were improved for potential reuse as construction

materials. Following laboratory verification for a

specific waste, we can recommend the DCR process for the field remediation of liquid organics

and heavy-metal-contaminated materials.
INTRODUCTION

Lime-based technologies

Lime (CaO) is one of the oldest chemicals used

on Earth (Wray 1991). Although history does not

record its discovery, lime is mentioned in the

Bible and in documents from ancient China as

well as Egypt, dating back about 6000 years. Lime

and its by-products used in the waste treatment

industry are summarized in Table 1. Many lime

products and by-products behave differently.

Chemically these by-products are poorly defined,

and their use in place of lime requires extensive

analysis to determine the equivalent quantity of

lime. Most common forms of lime used in waste

treatment are quicklime or unslaked lime (CaO)

and hydrated or slaked lime [Ca(OH)2]. In 1989,

more than 1.54 × 1010 kg (34 billion lb) of lime

were produced in the United States (Chemical and

Engineering News, 18 June 1990).

Lime is often used in water treatment to precipitate potentially toxic metals and neutralize

acids (Lewis and Boynton 1976, Boynton 1980).

Lime application for metal precipitation requires

pH adjustment to produce lowest solubility. Most

potentially toxic metals (e.g., cadmium, chromium, lead and nickel) are amphoteric, a process

where metal hydroxides show increased solubility at very low and high pH values. Weeter and

Jones (1987) concluded that a lime/fly ash additive significantly reduced the chromium (Cr) concentration of industrial sludge high in copper

(Cu), nickel (Ni), and Cr. The concentrations of

Cu and Ni were reduced by solidification. Furthermore, they stated that a lime/fly ash admixture is more cost effective than other agents such

as portland cement, lime, or sodium silicate. On

the other hand, Malone et al. (1987) found that the

fly ash/lime additive produced a product which

lowered the overall hydraulic conductivity of the

leachate but did not significantly lower the losses

Site Remediation via Dispersion By Chemical Reaction (DCR)

GILES M. MARION, JAMES R. PAYNE, AND GURDARSHAN S. BRAR

Table 1. Characteristics of major lime, limestone products, and

by-products used in waste treatment (Malone and May 1991).

Formula Bulk density

Reagent or composition (kg m–3) pH

High calcium quicklime CaO 769–1121 10.5–12.4

Dolomitic quicklime CaO–MgO 790–1400 9.0

High calcium hydrate Ca(OH)2 400–641 10.5–12.4

Normal dolomitic hydrate Ca(OH)2.Mg(OH)2 400–560 9.0

Dolomitic pressure hydrate Ca(OH)2.Mg(OH)2 480–640 9.0

High calcium limestone CaCO3 — 6.5

Dolomitic limestone CaCO3.MgCO3 — —*

Lime kiln dust 10–15% lime — ~ 12.4

Cement kiln dust Lime varies — ~ 12.4

Fly ash† Lime varies — ~ 12.4

Waste lime Lime varies — ~ 12.4

* Nonreactive.

† High calcium fly ash may have up to 2.4% uncombined CaO.
of heavy metals. The process using soluble silicate and cement additives gave the best containment of the heavy metals.

Crawley et al. (1984) outlined techniques for

using hydrated, high calcium lime to treat acidic

sludges. Remedial action using hydrated lime injection proved very effective in preventing

groundwater pollution under and around acid

waste pits. Morgan et al. (1984) developed and

tested a variety of lime and by-product mixtures

in treating oil refinery sludges. Blacklock et al.

(1982, 1984) described a technique for injecting a

lime/fly ash grout into landfills. Francis (1984)

reported an interesting application of hydrated

lime and limestone (oyster shell) to a landfill cap

to maintain alkaline conditions inside an industrial waste landfill.

In 1971, EIF (Ecology of France) developed

lime based fixation technology to detoxify wastes

rich in organic content (Separation and Recovery

Systems 1987). The examples of organic wastes

treated with the technology include crude oil,

refinery intermediate or final products, halogenated chemicals (e.g., PCBs), pesticides, sludges,

tars, painting wastes, and acid sludges. The permeability of the treated and compacted refinery

impoundment sludge waste was less than 1.0 ×

10–12 cm s–1.

In Dallas, Texas, Morgan et al. (1984) used several solidification agents to treat 19 million liters

of 30-year-old refinery oil sludge. The best solidifying agent found was fresh and stale cement

kiln dust. Furthermore, the kiln dust was also

tested in combination with small amounts of sulfur, cement and lime. Excellent solidification was

observed with cement and lime. Sulfur did not increase the strength significantly. The solidification process is simple, economical, and potentially applicable to other waste-disposal sites.

Zenobia and Turco (1985) studied the limebased stabilization technique to remediate hazardous waste site containing basins of inorganic

sludges, incineration residues, and spent biomass. They found that fly ash in combination

with lime and lime kiln dust were the best stabilizing agents. In France, Such and Roux (1981)

treated oil spills with quicklime and hydrophobic

lime (Boelsing reagent, see DCR Technologies).

They reported that the chemical reaction of dehydration occurred immediately in quicklime and

relatively delayed with hydrophobic lime.

Koper et al. (1993) reported that CaO is an

effective solid reagent for destruction of chlorocarbons (CCln). Furthermore, in a editorial note,

Rittenhouse (1993) wrote about CaO as an effective reagent for the destruction of CCl4. He discussed the work of O. Koper, Y.-Xi Li, and K.J.

Klabunde at Kansas State University.

Soundararajan (1991) found a strong interaction between high calcium–fly ash and polychlorinated biphenyls (PCBs) resulting in the total destruction of PCBs. Although he concluded that a

catalyst was probably responsible for the PCB destruction, the specific catalyst responsible is unknown. Einhaus et al. (1991) reported that PCBcontaminated soil treated with quicklime and

water significantly reduced (60 to 80%) PCB concentrations after five hours of treatment. However, they concluded that use of reactive quicklime as an in-situ treatment may be counterproductive due to the potential for migration of PCBs

as vapor or airborne particulates. Sediak et al.

(1991) attributed most PCB losses to volatilization due to the high heat of reaction for the CaO

hydration reaction. They concluded that the

“quicklime” treatment, per se, was not an effective treatment for PCB-contaminated soil.

Lime and lime products are useful in the engineered disposal of nonhazardous and hazardous

wastes. In some cases lime can be used to convert

hazardous waste to nonhazardous waste. Malone

(1984) reported that lime has great potential as a

neutralizing and cementing agent in waste management. Furthermore, he suggested that application of lime in hazardous waste reduction processes should increase because new ideas of its

use in liners, lime/fly ash grout injection, and

enhancement of methane production have been

evaluated and found safe and useful. Lime stimulates activity of anaerobic methane generating

bacteria responsible for the decay of refuse. Methanogenic bacteria function best in the pH ranges

of 6.4 to 7.4; however, some methane producers

can operate at high pHs of 9.0 (Klass 1984). Lime

in the form of quicklime is also used in drying

semisolid wastes. The hydration reaction of

quicklime eliminates water from the system and

produces a dry product which is easy to handle.

Malone and May (1991) found that the porosity and permeability of lime-amended soil

were greatly reduced by precipitation of contaminants in intergranular spaces in the soil. Initially

the amended soil had a permeability of 3.5 × 10–6

cm s–1; after 20 pore volumes of an acidic waste

had passed the column, the permeability

decreased to 4.0 × 10–8 cm s–1. In contrast, the permeability of the untreated soil ranged from 4.0 ×

10–6 cm s–1 to 1.0 × 10–6 cm s–1 after contact with

2
24 volumes of acidic waste. The lime-amended

soil decreased the permeability, reduced the

amount of leachate passing through the liner, and

reduced the total dissolved solvent content, trace

metal, and radionuclide concentrations in the

waste that moved through the liner. The limeamended liner was considered to be a very successful method for reducing the discharge of pollutants from acid waste piles.

Quicklime mixed with clay soils has been used

to produce hard, impervious soil liners in stock

ponds, small earth dams and irrigation channels

(Gutschick 1978). A compacted lime liner was

constructed by BASF Corp. for a hazardous waste

landfill on the Island of Flotzgrun near Speyer,

Germany (BASF 1983).

DCR technologies

The Dispersion by Chemical Reaction (DCR)

technologies are a group of patented waste treatment processes developed by F. Boelsing (University of Hannover, Germany) over 18 years ago in

Europe for the immobilization of heavily oiled

sludges, water-in-oil emulsions, oil contaminated

soil, industrial wastes such as acid-tars and heavy

metals (Boelsing 1988, 1995, Payne et al. 1992).

Hydrophobized CaO is used in the DCR process

to remediate organic-contaminated materials.

Calcium oxide, in its pure state, is hydrophilic.

Hydrophobic and oleophilic lime is prepared by

treating CaO with natural fatty acids. This process delays the hydration step and allows the

fatty acid-coated CaO reagent to preferentially

adsorb oils during a mixing step. The delayed

hydration then produces calcium hydroxide

[Ca(OH)2], which is fractured into submicron

sized particles (eq 1). This hydration reaction is

highly exothermic. Hydrate particles are homogeneously charged throughout their internal and

external cavities with the oil phase. The finely

dispersed Ca(OH)2 then slowly reacts with natural CO2 to generate relatively insoluble CaCO3

(eq 2):

CaO + H2O → Ca(OH)2 + energy↑ (1)

Ca(OH)2 + CO2 → CaCO3 + H2O. (2)

Thus, the oil components are immobilized in a

CaCO3 matrix to levels passing EPA Toxic Characteristic Leaching Procedure (TCLP) requirements. Other physical properties of the DCR

product that facilitate lower chemical leaching

are the compactibility of the soil-like product,

which lowers the hydraulic conductivity, and the

hydrophobicity of the product, which resists absorption of water. During the initial mixing step,

other reagents can be added for specific reactions.

For example, a hydrophobized nucleophilic reagent has been used for dehalogenation of PCBs

(Payne et al. 1992). Remediation of heavy metals

relies upon the formation of insoluble heavy

metal hydroxides and carbonates; when used to

remediate heavy metals, hydrophilic CaO is used

as the primary reagent (Marion et al., in prep.).

The objectives of this project were to 1) evaluate

the DCR process for remediating soils contaminated with pesticides, petroleum hydrocarbons

(oils and fuels), and heavy metals in cold regions

and 2) evaluate DCR-treated oil-contaminated

soil as a non-frost-susceptible (NFS) construction

material. These objectives were met with three

major studies. We evaluated the DCR process to

remediate 1) hydrocarbons at Eareckson AFS on

Shemya in the Aleutians, 2) pesticide-contaminated soils from Rocky Mt. Arsenal, and 3)

heavy-metal-contaminated soils from a former

zinc smelter site at Palmerton, Pennsylvania.

METHODS AND MATERIALS

This final CPAR report will focus on the highlights of the three studies at Shemya, Rocky Mt.

Arsenal, and the Palmerton zinc smelter site, with

primary focus on the chemistry. Other physical

and chemical testing beyond that described below and in the Results and Discussion were done at

all these sites. For a complete description of the

experimental work, refer to the following publications: Payne et al. (1994), Brar and Marion

(1995), Marion et al. (1997), Payne and Marion (in

press), Marion et al. (in prep.).

Shemya study

Shemya Island (5.6 × 2.4 km) is located at the

western tip of the Aleutian Archipelago, 2400 km

southwest of Anchorage. Historically Shemya

has been uninhabited. The earliest written records of human activity were by Russians who introduced blue foxes on Shemya for the purposes

of fur farming in 1775. In 1943, the U.S. Army’s

4th Infantry and 18th Engineering Regiments

developed Shemya and constructed a runway

and aircraft hangers, which were used during

World War II. Today, the U.S. Air Force occupies

the entire island; the primary mission of the

Eareckson Air Force Station is to monitor space

and missile activities.

3
Shemya Island is dominated by a persistent

low pressure system known as the “Aleutian

Low.” Frequent storms track across the north

Pacific into the Aleutian Islands. The Aleutian

low pressure cells are responsible for the relatively mild maritime climate of the Aleutian Islands.

Summer fogs are severe and preclude any flying

as often as one day in four. The persistent wind,

fog, and salt spray are responsible for the highly

corrosive and harsh conditions.

The mean annual temperature is 3.6°C. The

minimum and maximum recorded temperatures

are –13.9 and 17.2°C, respectively. The diurnal

temperature variation rarely exceeds 6°C. Measurable winds are recorded 363 days yr–1 with a

mean annual wind velocity of 32 km hr–1. Wind

direction is evenly distributed without any true

prevailing wind direction. Precipitation occurs

more than 330 days yr–1. Average annual precipitation is 79.5 cm. The average annual snowfall is

178 cm. Drifting snow and driving rain are common in winter because of strong wind velocities

(CH2M Hill 1990).

Eareckson AFS has several types of soil contamination problems which are the result of historic and ongoing USAF operations. The primary

focus of this study was on a site identified as the

PS-9 Asphalt Tar Drum Storage Area. This site is

contaminated as a result of leaked asphalt tar

stored in 55-gal. drums. In addition, we examined, at the laboratory scale, the efficacy of the

DCR process to remediate organic-contaminated

soil from three sites identified as 1) Oil/Water

Separator Pond Sediment, which is contaminated

with oils and greases; 2) Cell 21 Oiled Peat, which

is contaminated with JP–4 and other volatile

fuels; and 3) Fire Training Pit, which is contaminated with diesel residuals that were not volatilized or burned during fire training exercises.

SOUND Environmental Services (now known

as SOUND/epic), Anchorage, Alaska, under contract with the U.S. Army Cold Regions Research

and Engineering Laboratory (CRREL), demonstrated the DCR technology at Eareckson AFS,

Shemya. To treat the asphalt tar waste, SOUND

used a skid-mounted transportable treatment

unit (Fig. 1). The transportable treatment unit

consists of a control panel, mixer, lime-feed apparatus, water container, and conveyer assemblies.

Asphalt tar was excavated with a Link-Belt excavator and stockpiled on the site. The excavated

asphalt tar material and accompanying soil were

added to the pug-mill mixer on a volumetric basis.

Lime was metered into the mixer on a timed basis

dependent on the volume of waste addition.

Occasionally water was also added to the mixture

at the discretion of the mixing overseer.

Two bulk soil samples (18 kg each) for laboratory physical tests were collected by mixing different batches of DCR-treated asphalt material in

the field. These samples were air-freighted to

CRREL without any special provisions for preservation. Three soil samples were used in the physical tests. Samples 1 and 2 were from the two separate buckets, and sample 3 was a composite

sample from the two buckets.

ASTM Method D 5084–90 was used to determine the saturated hydraulic conductivity (permeability) of DCR-treated asphalt tar materials

before and after one freeze–thaw cycle. Rocks

4

Figure 1. Transportable treatment unit used on the Shemya study.

Water

Lime-feed

Apparatus

Mixer

Conveyor

Control Panel

↓ ↓

↓
greater than 1.0 cm were excluded from the test

samples. Four sets of hydraulic conductivity

measurements were made on each sample. The

test measures one-dimensional laminar flow of

water within saturated porous materials. This

test assumes hydraulic conductivity is unaffected

by hydraulic gradient. The following procedures

were used to freeze the samples. The compacted

soil samples used to determine the hydraulic conductivity of unfrozen soil were placed in a coldroom. Two cold plates, one at the bottom and

another at the top of the test sample, were positioned. Vermiculite was used as insulating material around the test sample. Temperatures of the

test samples were kept at 3°C for one night. Temperatures of 0° and –6.1°C were maintained for

the next 18 hr at the bottom and top of the sample,

respectively. Then temperatures at the bottom

and top of the specimen were maintained at 0°C

and –10°C for an additional 5 hours. These temperatures at the bottom and top of the sample

were further lowered to –3°C and –12°C, respectively, for an additional 24 hours. For thawing the

samples, temperatures were raised to 3°C and

4°C at the bottom and top of the cell for 24 hours.

The gravimetric water content of DCR-treated

asphalt tar samples was determined by heating at

105°C for 24 hours (ASTM Method D2216–90).

These tests were performed in a field laboratory

at the treatment site. Three soil samples were

drawn from the untreated asphalt tar material,

and four samples were drawn from different

batches of field DCR-treated asphalt tar material.

In addition, three replicate samples were taken

from the laboratory DCR-treated batches.

Temperatures of the DCR-treated asphalt tar

material were measured in the field with copperconstantan thermocouples that were fabricated

and tested at CRREL. Four thermocouples, each

separated by 30 cm, were attached to a wooden

stick. Two wooden sticks with eight thermocouples were embedded horizontally into an untreated asphalt tar pile or a DCR-treated pile. Air

temperatures were measured at a 2-m height

above the ground with unshielded thermocouples. Data were logged every minute with a datalogger (model CR–10, Campbell Scientific).

Asphalt tar-soil samples for chemical analyses

were collected in quality certified (QC) glass jars

and stored outdoors (–5° to –1°C) until ready for

shipment. Five untreated samples were collected

around the excavated tar pile on 27 January 1994.

Five treated samples were collected during the

DCR operation on 27–28 January. These chemical

samples were air-freighted on “blue ice” in Igloo

coolers from Shemya to Anchorage on 28 January,

stored in a freezer overnight, and then shipped

on 29 January via Federal Express to the U.S.

Army Corps of Engineers Environmental Laboratory in Hubbardston, Massachusetts (henceforth

to be called the Environmental Lab), where they

arrived on 31 January. Total petroleum hydrocarbons (THP) (as diesel) was determined using EPA

Methods 3550/8015M (USEPA 1992). Toxic Characteristic Leaching Procedure (TCLP) extracts for

TPH were done using EPA Methods 1311/8015M.

Volatile organics were determined using EPA

Method 8260. TCLP extracts for volatile organics

were done using EPA Methods 1311/8260.

Samples from the Oil-Water Separator Pond

Sediment, the Cell 21 Oiled Peat, and the Fire

Training Pit were collected, DCR-treated in the

portable field laboratory using an Eirich mixer,

and analyzed by Commercial Testing & Engineering Company in Anchorage, Alaska. TPH (as diesel) was analyzed using EPA Methods 3510/

3550/8100M; vapor phase hydrocarbons were

analyzed using EPA Methods 5030/8015M/8020;

and BTEX constituents (benzene, toluene, ethylbenzene, and xylenes) were analyzed using EPA

Method 8020. TCLP extracts (EPA Method 1311)

were used to measure the leachability of TPH and

BTEX constituents.

Rocky Mt. Arsenal study

Four separate 15-gal. (56.7-L) drums containing representative soil samples were transported

under full chain of custody to SOUND/epic.

Upon initial receipt, each sample was further

homogenized and examined to assess handling

and physical characteristics. An aliquot of each

was removed for hexane extraction and gravimetric determinations of oil and grease and total

petroleum hydrocarbons (TPH). The extracts

were then further characterized by flame ionization detector (FID) gas chromatography (GC) to

determine total resolved hydrocarbons and the

approximate molecular weight range (distillate

cut fraction) of any petroleum-type constituents

in the sample. Electron capture detector (ECD)

GC was then used to screen for pesticides.

 Based on the chromatograms of the four samples, we selected the most contaminated soil

(“soil-amended Basin F sludge”) for all subsequent work (Payne and Marion, in press). It was

known that the majority of the contamination

originated in the Basin F Liquid (Table 2), and for

this reason as well, this sample was selected. In

5
addition to significant levels of pesticides, the

Basin F Liquid (later mixed with clean soil to yield

the “soil-amended Basin F sludge”) contained

very high concentrations of inorganic salts [e.g.,

NaCl, NH4Cl, and (NH4)2SO4] as well as 14% urea

(Table 2).

It was determined that the high levels of sulfate

(and possibly urea) in the waste (Table 2) were

interfering with the CaO hydration inherent to the

DCR process. As a result, uneconomically high

levels of CaO reagent were required to obtain an

acceptable product. To circumvent this problem,

additional tests were undertaken to see if the waste

could be pretreated with lime milk [hydrated

Ca(OH)2] to tie up the sulfate (for example as gypsum, CaSO4

.

2H2O) and also remove the urea.

These tests were very successful, and it was found

that addition of 30% lime milk slurry in H2O

[Ca(OH)2 at approximately 10–13% of contaminated soil weight] was sufficient to tie up all the sulfate as gypsum. Then with subsequent addition of

dry CaO for the DCR reaction, it proceeded without delay and at economically feasible reagent

addition levels. The lime milk pretreatment also

proved to be an excellent way to remove ammonia

by volatilizing any ammonium originally present

as ammonium sulfate and catalyzing the hydrolysis of urea to CO2 and ammonia. In field applications, this approach could be used to release and

reclaim ammonia through a specially designed

emissions control capture system on the transportable treatment unit prior to DCR processing.

The DCR process (unlike other pozzolan-based

stabilization approaches) achieves its greatest

technological advantage with wastes containing

very high (> 10–30%) levels of organics (e.g., diesel oil residuals and waste oils) because such materials facilitate transfer of the contaminants of

concern onto the hydrophobic CaO reagent before the dispersion by chemical reaction takes

place. It was apparent that there would not be

sufficient free organic (oily) phase in the sludge/

soil matrix for optimum DCR processing. It was

determined in a wettability study that addition of

a benign food additive (Archer Daniels Midland

[ADM] regular soy oil soap stock) at 10% of soil

weight significantly improved the water repellency of the resultant product, so its addition was

implemented as a standard procedure for all further tests.

Following the initial scoping studies completed

in the first week after sample receipt, 0.7-kg scale

batch preparations were undertaken to generate

sufficient DCR-treated material for independent,

third-party laboratory testing. The initial DCR

product prepared for outside laboratory analyses

was generated from 55% CaO addition to limemilk pretreated soil plus 10% ADM soy oil. The

total CaO reagent requirement (including that

used to generate the lime milk slurry) for this

sample was 64.7%. This material and a sample of

the raw untreated waste soil were packaged for

shipment and transferred under chain of custody

to the Environmental Lab. The following analyses were performed: FID GC (Diesel Range Total

Petroleum Hydrocarbon Screening, EPA Method

8015M), ECD GC (EPA Method 8081, Pesticide and

PCB Analyses), GC/MS (EPA Method 8270, Total

Waste Analyses), TCLP (EPA Method 1311 Extraction for Pesticides, EPA Method 8081).

Subsequent to sample shipment, several additional larger-scale (1.5 kg) scoping experiments

were completed with SOUND/epic’s high intensity Eirich Mixer. Through these later determinations, it was found that at the larger batch size

and with more aggressive mixing, an acceptable

product could be obtained with only a 23% CaO

addition to lime-milk pretreated soil (total CaO

addition, including preparation of lime milk was

27.4%). Because the 27.4% CaO addition is more

representative of what might be utilized in field

applications, samples of this DCR-treated material were compacted into a Proctor cylinder for

physical testing. A portion of this compacted cylinder was allowed to cure and was set aside for

additional chemical analyses to assess the effects

of lower DCR reagent utilization and sample

6

Table 2. Descriptive chemical characterization of RMA Basin F liquid*

(highest historical data).

Constituent mg/L

Water 620,000

Major metals

Sodium (Na) 65,000

Copper (Cu) 5,860

Potassium (K) 2,900

Major inorganics

Chloride (Cl–) 159,000

Ammonia (NH3) 60,900

Sulfate (SO4

=) 27,000

Total phosphorus 16,200

Nitrate (NO3

–) 1,300

Additional components

Urea 143,000

Dimethylmethylphosphonate 2,000

* From R.F. Weston Document 1212WG.APA

(12/17/90).
compaction on pesticide sequestering and leachability. This compacted cylinder sample was

shipped via Federal Express under chain of custody to the Environmental Lab. The same suite of

analyses used for the raw untreated soil sample

and loose (uncompacted) 64.7% DCR-treated

material was requested, with the proviso that the

cylinder be crushed to the minimum extent necessary to pass through the 9.5-mm sieve (specified in the TCLP test) before leaching.

Palmerton zinc smelter study

Palmerton is in Carbon County, Pennsylvania,

just north of the Lehigh Water Gap. Current vegetation on the Blue Mountain site is depauperate

with many areas completely barren; common

species on these sites include Sassafras albidum,

Nyssa sylvatica, and Arenaria patula (Buchauer

1973). The soils on top of Blue Mountain are Dekalb very stony loams, formed on periglacially

worked, acid, gray sandstone (Fisher et al. 1962).

The soil is classified as a loamy-skeletal, mixed,

mesic Typic Dystrochrept. These soils are strongly acidic, well drained, and contain many stones.

The contaminated soil was collected in plastic

bags at the Palmerton site about midslope on the

north aspect of Blue Mountain and shipped in

metal drums to CRREL. The “clean” soil was a

Charlton silty sand and was collected locally.

These soil samples were air-dried on large tarps

and sieved to pass a 2-mm screen.

The air-dried and sieved soils were DCR-treated at the SOUND/epic laboratory in Carlsbad,

California, in August 1995. Contaminated soil

and CaO (10% w/w) were mixed in an Eirich

mixer with sufficient water to assure proper hydration (eq 1). The resultant product was a dry,

dusty, soil-like material.

Total, TCLP extractable, and water soluble

heavy metals were measured by the Environmental Lab. Total soil analyses for Ag, Be, Cd, Cr, Cu,

Ni, Sb, and Zn were done using EPA Methods

3051 (digestion) and 6010 (ICP); for As, Methods

3051 and 7060 (AA) were used; for Pb, Methods

3051 and 7421 (AA) were used; for Se and Tl,

Methods 3051 and 7740 were used; and for Hg,

Method 7471 (AA) was used (USEPA 1992). TCLP

extractions and analyses for Ag, Be, Cd, Cr, Co,

Ni, Sb, Zn, As, Pb, and Se were done using EPA

Methods 1311 (extraction) and 6010 (ICP); TCLP

extractions and analyses for Hg were done using

EPA Methods 1311 and 7470 (AA) (USEPA 1992).

The TCLP tests used acetic acid extraction fluid

no. 2 (USEPA 1992) for all samples because of the

alkalinity of the DCR-treated soils. The water soluble tests were identical to the TCLP tests except

that water was used as the extraction fluid.

The CRREL greenhouse column experiments

were designed to assess the efficacy of the DCR

process to stabilize heavy metals against leaching

losses and plant uptake. The clear acrylic columns were 60 cm in length and 5 cm in inside

diameter. These columns were split longitudinally

to facilitate root sampling at the conclusion of the

study. The tubes were placed in a dark box with

each tube inclined 15° from the vertical to facilitate root growth observations. Each tube was divided into three sections. On the bottom was a 14-

cm sand zone; on top of this layer was a 20-cm

experimental soil zone; and the surface 25-cm

zone consisted of a clean (i.e., uncontaminated)

soil.

The four experimental soils were 1) a Charlton

silty sand (clean soil), 2) a Palmerton silt (contaminated soil), 3) a DCR-treated Palmerton soil, and

4) a compacted DCR-treated Palmerton soil. The

compacted treatment was designed to assess

whether plant roots would grow around the

DCR-treated soil if given an opportunity. The

compacted samples were 4.0 cm in diameter and

20 cm in length and were prepared by dropping a

weight 10 times on the soil encased in a plastic

tube. The final density of these cores was 2.02

± 0.05 g cm–3. The core was then placed in the center of the column and clean soil was filled in

around the core.

The two plant species were Pennfine perennial

ryegrass (Lolium perenne) and Pixie tall fescue

(Festuca arundinacea). These two grasses were

chosen because tall fescue shows promise for

heavy metal tolerance, while perennial ryegrass

has little tolerance for heavy metals (Chaney

1993). There were four replicates of each treatment for a total of 32 columns (4 soils × 2 plant

species × 4 replicates).

The experimental columns were prepared on 7

December 1995. Unfortunately the greenhouse

heating system broke down shortly thereafter,

which caused the columns to freeze. Problems

with the heating system and other factors delayed planting with tall fescue and perennial

ryegrass until 19 January 1996. Seeds were germinated on filter paper, planted 1.0 cm deep in the

tubes, and after emergence and early growth,

thinned to four plants/tube. Plants were watered

as needed with half-strength, pH-neutral Hoagland’s nutrient solution (minus Zn) (Johnson et

al. 1957). Every third watering was with distilled

7
water to reduce salt accumulation. Ten times during the experiments leachates were collected and

analyzed for pH and heavy metals. The plants

were harvested on 23 April 1996, rinsed in deionized water, and separated into shoots, crowns,

and three root samples from the three soil zones.

The plant material was frozen until ready for

analyses.

Leachates were analyzed for Zn, Pb, Cu, Cd,

and pH. Samples were refrigerated after sampling, but were not filtered. There was no visual

evidence for any significant movement of suspended material or organics as judged by settling

out of suspension or discolored solutions. Working standards for heavy metals were prepared

from 1000-ppm Fisher primary standards. A

Perkin-Elmer Model 5000 atomic absorption

spectrophotometer (AAS) was used for the heavy

metal analyses. The pH meter was calibrated

with Fisher standards at pH = 10.00 ±0.02 and pH

= 7.00 ±0.01.

The plant material was dried in an oven at

80°C, then ground in a stainless steel Wiley mill to

pass a 20-mesh screen. Subsequent plant processing for heavy metal analyses closely followed the

procedures used by Brown et al. (1994). Briefly,

plants were ashed at 480°C for 16 hours, digested

with 5 mL of concentrated HNO3, evaporated to

dryness, taken up in 5 mL of 3 M HCl, and then

diluted to volume (25 mL) with 1 M HCl. Blanks

were carried through the identical process. These

solutions were analyzed on a Perkin-Elmer

model 5000 AAS. Working standards were prepared from primary standards (Fisher, 1000 mg

L–1) and contained the same HCl concentrations

as the samples to assure a similar sample matrix.

RESULTS AND DISCUSSION

Shemya study

This study involved more physical testing of

the treated material than the subsequent studies,

because there was interest in possibly using this

material for either road subgrade or in a landfill

cover in an area subject to freeze-thaw cycles.

The water content of untreated asphalt tar was

around 30% by weight; both laboratory and field

DCR-treated asphalt tar material contained significantly less moisture (Fig. 2). This dehydration

of the treated material is partly due to formation

of Ca(OH)2 and partly due to release of steam in

the exothermic reaction (eq 1). The laboratory

treated material contained significantly higher

water compared to field treated material.

The hydraulic conductivity was determined

on three DCR-treated asphalt tar samples subjected to a single freeze-thaw cycle. Although the

hydraulic conductivity increased with a single

freeze thaw cycle, the difference was not significant (Table 3). Because of the high levels of sand

and gravel in the raw waste, the DCR-treated tar

material was coarse-textured. As a consequence,

the hydraulic conductivity was high (Table 3).

Reduction of hydraulic conductivity to a regulatory limit of 1.0 × 10–5 cm s–1 for some applications (e.g., landfill covers) will necessitate mixing

of the treated material with finer-textured silts

and clays. A single freeze-thaw cycle increased

the hydraulic conductivity by 37% (Table 3),

which agrees with Chamberlain (1994) who

found that the hydraulic conductivity of most

compacted clays increased significantly after

freezing and thawing. Chamberlain (1994) reported that freeze-thaw cycles are the major problem affecting the design and performance of

landfill containment structures and surface impoundment systems in cold regions. The coarse

texture and high hydraulic conductivity of this

DCR-treated tar-soil mixture may limit potential

reuse.

8

Figure 2. Water content of untreated soil-asphalt tar

and laboratory and field DCR-treated material.

Table 3. Changes in hydraulic conductivity

after one freeze–thaw cycle.

Dry

Sample density Hydraulic conductivity (cm sec–1)

no. (g cm–3) 0 1 Ratio

1 1.41 1.03×10–3 1.12×10–3 1.09

2 1.36 5.76×10–4 9.85×10–4 1.71

3 1.37 2.06×10–4 2.67×10–4 1.30

Mean 1.38 6.04×10–4 7.91×10–4 1.37
Fifteen peaks of elevated temperatures for various DCR-treated batches were recorded on 26–27

January 1994 (Fig. 3). Sharp temperature peaks

were the result of placing the probes in a batch for

short periods. Plateaus and steady declines in

temperature were the result of leaving the probes

in a given batch for extended periods. The temperature of treated material increased to between

35° and 95°C. The temperature of untreated material was close to 0°C, and no change was observed on either sampling day. On 26 January, air

temperatures started increasing after 1130 hours

and reached a maximum of 6°C in an unshielded

position.

The DCR reaction was both highly exothermic

and dehydrating. The high temperatures (> 90°C,

Fig. 3) could potentially have an adverse effect on

soil microorganisms. On the other hand, the dehydration produced a drier soil material, which

should facilitate its reuse. The original tar-soil

mixture was very dark and consisted of many

large tar masses, some weighing 2–5 kg. The endproduct was more soil-like, drier, with only a few

small (0.5-kg) tar balls. The DCR process, overall,

improved the physical properties of this asphalt

tar material for reuse.

Many of the volatile organics in the asphalt tarsoil were below the limits of detection (Brar and

Marion 1995). Statistically significant differences

between untreated and DCR-treated soils were

only found for acetone, 2-butanone, 4-methyl–2-

pentanone, and total xylenes (Table 4). With the

9

Table 4. Total extractable concentrations of TPH and volatile organics in asphalt-tar samples (mean ±1 SE).

Minimum

detectable

Compound Units limit Untreated Treated

Acetone* μg kg–1 — 66 ± 14a 466 ± 14b

2–Butanone μg kg–1 2.3 11 ± 5a 226 ± 12b

Benzene μg kg–1 1.0 0.5 ± 0.0a 3.9 ± 2.1a

4–Methyl–2–pentanone μg kg–1 2.3 1.2 ± 0.0a 21 ± 2b

Toluene μg kg–1 0.58 7.1 ± 1.8a 4.8 ± 1.6a

2–Hexanone μg kg–1 1.9 30 ± 23a 49 ± 13a

Ethylbenzene μg kg–1 0.56 6.7 ± 1.4a 6.5 ± 1.5a

Total xylenes μg kg–1 1.1 64 ± 13a 31 ± 3b

TPH mg kg–1 — 2602 ± 621a 2160 ± 254a

* Also detected in method blanks run with with samples.

Statistically significant differences are designated by different lower-case letters.

Figure 3. Changes in air, stockpiled untreated, and DCR-treated material temperatures.
exception of total xylenes, volatile organic concentrations were higher in treated than in untreated samples. Elevated levels of ketones may

be the result of in-situ oxidation of corresponding

alcohols present, but not analyzed for, in the

starting material.

Increasing organic concentrations runs

counter to the basic principle of the DCR process

that is designed to encapsulate organics rendering them less available. We believe that this outcome was caused by two factors. One, the mixing

process broke up the tar masses greatly increasing contact surface areas for the extracting solutions. Two, the hydrophobic CaO never properly

dispersed into the asphalt tar because at the prevailing field temperatures (< 0°C), the asphalt tar

was a solid. The heat of mixing was insufficient

for a proper CaO dispersion into the organic

phase prior to the hydration reaction. Under cold

climates, heating the asphalt tar prior to mixing

would probably lead to a better DCR product.

Most constituents were either not detected in

the TCLP extracts or were present at levels that

were just above the detection limits (Table 5).

There was no leachable benzene detected; when

other leachable aromatics were detected, they

were four orders of magnitude below applicable

drinking water standards. The most water-soluble constituents, notably acetone and 2-butanone,

were generally only present at low ppb levels,

three to four orders of magnitude below the regulatory limit for 2-butanone, the only ketone for

which limits exist.

The TPH in the solid raw and DCR-treated tar

samples is quite variable, and no doubt reflects

differing amounts of small tar flakes in the soil/

tar samples (Table 4). Because of the variability,

there is no statistically significant difference in the

samples before and after treatment. Conversely,

when the TCLP results are examined, there is a

slight increase in the total leachable TPH in the

samples after treatment (Table 5). Here again, the

increase in leachability is believed to be due to the

increase in surface area associated with the finely

dispersed DCR product compared to the hard

and almost intractable obsidian-like tar lumps in

the starting material. This leachability would be

significantly lower in hard compacted DCR soil

bodies, as in subgrade for parking areas or road

construction, compared to the loose, fine product

subjected to TCLP testing in the laboratory.

In contrast to the solid asphalt tar, the other

contaminants evaluated at the laboratory scale

generally led to large decreases in organic concentrations following DCR treatment (Tables 6

and 7). There were at least two reasons for this

contrast. One, the other organics were present in

the liquid state (e.g., oils, greases, JP–4, diesel) at

these sites which facilitates proper adsorption of

the organic phase onto the hydrophobic CaO before the DCR reaction. Two, the other organics

were present at much higher concentrations initially for these three sites (Tables 6 and 7) compared to the asphalt tar site (Tables 4 and 5).

There was a dramatic reduction in the extractable TPH after DCR treatment for the Oil/Water

Separator Pond Sediments, and this presumably

reflects a combination of volatilization and

Ca(OH)2 encapsulation of intermediate- and higher-molecular-weight hydrocarbons associated

with the oils and greases released to the pond

(Table 6). The total lower-molecular-weight (gaso10

Table 5. Total extractable concentrations of TPH and volatile organics in

TCLP extracts of asphalt-tar samples (mean±1 SE).

Minimum Alaska or

detectable Federal

Compound Units limit Untreated Treated standard

Acetone* μg L–1 — 23 ± 14a 156 ± 111a n.a.†

2–Butanone μg L–1 1.6 1.4 ± 0.4a 6.4 ± 1.1b 200,000

Benzene μg L–1 0.63 0.3 ± 0.0a 0.3 ± 0.0a 5

4–Methyl–2–pentanone μg L–1 1.5 1.3 ± 0.2a 2.2 ± 0.4a n.a.

Toluene μg L–1 0.58 0.37 ± 0.08a 0.40 ± 0.11a 1,000

2–Hexanone μg L–1 1.2 0.6 ± 0.0a 1.7 ± 0.1b n.a.

Ethylbenzene μg L–1 0.56 0.28 ± 0.00a 0.56 ± 0.18a 700

Total xylenes μg L–1 1.1 1.2 ± 0.1a 2.4 ± 0.4b 10,000

TPH mg L–1 — 0.73 ± 0.02a 1.24 ± 0.07b n.a.

* Also detected in method blanks run with these samples.

† n.a. = no applicable State or Federal standard is set.

Statistically significant differences are designated by different lower-case letters.
11

Table 7. Total extractable concentrations of TPH and BTEX constituents in TCLP

extracts of organic-contaminated soils.

Oil/water sep. pond Cell 21 oiled peat Fire training pit

Compound Units Untreated Treated Untreated Treated Untreated Treated

Benzene μg L–1 n.d.(1) † n.d.(1) n.d.(1) n.d.(1) 110 n.d.(1)

Toluene μg L–1 3.6 4.9 5.6 11 97 6.2

Ethylbenzene μg L–1 n.d.(1) n.d.(1) 64 8.3 33 n.d.(1)

Total xylenes μg L–1 n.d.(1) n.d.(1) 308 54 183 1.7

Total volatile

 hydrocarbons mg L–1 0.183 0.026 1.93 0.446 1.00 0.169

TPH mg L–1 2.93 1.06 0.718 2.72 1.92 1.93

* n.d. = not detected at the stated minimum laboratory reported level in parentheses.

Table 6. Total extractable concentrations of TPH and BTEX constituents in organiccontaminated soils.

Oil/water sep. pond Cell 21 oiled peat Fire training pit

Compound Units Untreated Treated Untreated Treated Untreated Treated

Benzene μg kg–1 n.d.(20)* n.d.(20) 7030 n.d.(54) 621 n.d.(25)

Toluene μg kg–1 43 115 121,000 713 8040 25

Ethylbenzene μg kg–1 39 27 138,000 2,290 7010 n.d.(25)

Total xylenes μg kg–1 185 360 584,000 11,500 29,500 62

Total volatile

 hydrocarbons mg kg–1 8.25 6.66 10,600 164 518 2.8

TPH mg kg–1 39,600 4,870 111,000 39,000 35,500 38,700

* n.d. = not detected at the stated minimum laboratory reported level in parentheses.

line and diesel range) volatile hydrocarbons in

these samples were not present at very high concentrations to begin with (those constituents

would have long since been lost from the soil/

water separator pond), and as such, there was not

a large reduction in the total volatiles for these

samples. As shown by the BTEX values, there is

no benzene either before or after DCR treatment,

and it appears that the toluene and total xylenes

may have been slightly liberated by the increased

surface area of the dry, finely dispersed product

compared to the wet pond sludge that originally

made up the sample. TPH in TCLP extracts was

reduced by a factor of three, and total volatile

hydrocarbons were reduced by a factor of six

(Table 7). The individual BTEX constituents were

either not detected or just at the limit of detection,

both before and after DCR treatment.

The Cell 21 oiled peat was heavily contaminated with JP–4 and other volatile fuels. There was

a dramatic reduction in both the extractable TPH

and total volatile hydrocarbons after DCR treatment (Table 6). Benzene and toluene were reduced by over two orders of magnitude, and the

other volatile constituents were reduced by a factor of 50 to 60. The TCLP data for these samples

were somewhat more variable (Table 7). TPH in

TCLP extracts appeared to increase slightly; this

is presumably due to the increased surface area of

the dry, finely dispersed product compared to the

wet peat sample, which would be more difficult

to leach. The leachable total volatile hydrocarbons were reduced as were ethylbenzene and

total xylenes (Table 7).

For the Fire Training Pit samples, the majority

(>98 %) of the hydrocarbon contamination would

come from higher-molecular-weight diesel residuals which had not been volatilized or burned off

during fire training exercises. Therefore, the total

extractable TPH constituents remaining in the

soil/tar would not be expected to be altered significantly by the DCR process (Table 6). The DCR

process is designed to convert liquid (mobile)

hydrocarbons into a solid nonmobile phase,

which will resist all natural forms of migration

(i.e., surface runoff and groundwater), but not

necessarily extraction by organic solvents such as

methylene chloride. Therefore, it is not surprising

to see the high extractable TPH values both before and after treatment in this instance. Those

volatiles that were still present in the sample at

518 ppm were reduced to less than 3 ppm during

the exothermic reaction; this was also reflected in

the significant reductions of BTEX constituents to

nearly nondetectable levels. For these Fire Training Pit samples, there was essentially no change
in the leachable TPH (Table 7), a very significant

reduction was observed in the total volatile hydrocarbons, and one to two orders of magnitude

reductions were observed for the individual

BTEX constituents.

Both volatilization and Ca(OH)2 encapsulation

may have played a role in the disappearance of

organic constituents. Lower-molecular-weight

volatile constituents such as BTEX are no doubt

lost to volatilization; however, intermediate- and

higher-molecular-weight petroleum hydrocarbons are probably largely sequestered into the

newly formed Ca(OH)2 matrix.

Comparison of TCLP extract organic concentrations to Federal Drinking Water Standards (Table 5) helps place these concentrations in perspective. The benzene concentration from the Fire

Training Pit before DCR treatment (Table 7) was

the only case where a measured concentration

(110 μg L–1) exceeded the Federal Drinking Water

Standard (5 μg L–1); after DCR treatment, benzene was not detectable. In all other cases, the organic concentrations were well below drinking

water standards and therefore pose minimal pollution danger for surface or groundwaters.

Rocky Mt. Arsenal study

Two basic analytical approaches are currently

utilized by the U.S. EPA to evaluate reduction in

contaminant mobility and total constituent concentrations. These are Total Waste Analyses

(organic solvent extraction followed by GC or

GC/MS analyses) and leachability usually by the

TCLP test. The volatile lower molecular weight

alkylated- and chlorinated-benzenes in the RMA

soil sample were essentially eliminated during

the DCR Process. This is due to volatilization or

steam stripping during the exothermic hydration

of CaO to Ca(OH)2, and in field implementation

these constituents can be captured using transportable treatment units equipped with modular

emissions control systems. Their removal is important in that they constitute the more watersoluble constituents, which can contribute to

leachate or groundwater contamination if not

otherwise controlled.

With regard to the pesticides and semivolatile

organics in the RMA soils, it should be emphasized again that the DCR Process is not a destructive technology. Any liquid (or solubilized) organic

wastes treated by the DCR process are homogeneously dispersed into very fine (submicron

sized), hydrophobic particles. Since the pesticides

present in the RMA soil samples are for the most

part solids under ambient-temperature conditions, the ADM soy oils were added in an effort to

partially “solubilize” them and facilitate transfer

to the CaO before hydration. Therefore, the slight

increase in the gravimetric oil and grease value

(Table 8) for the 64.7% reagent addition is no

doubt due to the addition of the ADM soy oil.

This increase is partially offset by oil sequestration/adsorption (even against organic solvent

extraction) into the voids, cracks, and fissures of

the newly formed Ca(OH)2 generated during the

DCR Process. More importantly, there is a significant decrease in the total resolved pesticides in

the 64.7% reagent addition as measured by ECD

GC at SOUND/epic, and this is also reflected in

the individual pesticides reported by the Environmental Lab. These reductions in total and

individual pesticide concentrations are believed

to be due primarily to simple dilution from DCR

reagent addition. Similar reductions are noted for

12

Table 8. Summary of selected constituent analyses of RMA Basin F soil sample no.

24216 at different levels of DCR reagent addition with and without compaction.

64.7% DCR 27.4% DCR 27.4% DCR

Raw waste reagent reagent reagent

before addition addition addition

Waste constituent treatment (loose) (loose) (compacted)

Gravimetric oil & grease1 (mg/kg dry wt) 10,700 12,900 41,800 15,200

Total resolved pesticides1

ECD GC (mg/kg dry wt.) 3,270 2,150 2,110 1,110

Aldrin (ng/g dry wt.) 390,000 270,000 N.A. 350,000

Dieldrin (ng/g dry wt.) 260,000 180,000 N.A. 220,000

Endrin (ng/g dry wt.) 140,000 100,000 N.A. 120,000

1,2,4-Trichlorobenzene (ng/g dry wt.) 210 120 N.A. < 16

Hexachlorobutadiene (ng/g dry wt.) 6,900 630 N.A. 750

Analyses denoted by superscript one (1) completed by SOUND/epic, all others by U.S. Army Corps of

Engineers Environmental Laboratory, Hubbardston, Massachusetts.

N.A. – Not analyzed.
most of the semivolatile constituents with an order of magnitude decrease in hexachlorobutadiene (presumably from volatilization).

In the low-reagent case (27.4%), the gravimetric oil and grease concentration increased more

than was the case for the high-reagent addition

(Table 8). This is particularly true with the loose

27.4% product before compaction, and reflects

the fact that less CaO was added, so there would

be less sequestering of the soy oil against organic

solvent extraction. With subsequent compaction,

however, it is more difficult to extract the “oil and

grease” with organic solvents, and a concomitant

decrease in gravimetric oil and grease content is

observed. As noted with the higher DCR reagent

additions, significant reductions in total resolved

pesticides by ECD GC are observed, and this reduction is further improved with compaction. No

individual pesticide data are available for the

loose 27.4% DCR-treated product, but with the

compacted product, individual constituent concentrations are reduced, as expected, to an intermediate value between those observed in the raw

soil and the 64.7% DCR-treated material (Table 8).

The reductions of aldrin, dieldrin, and endrin can

be accounted for by a simple dilution with reagent CaO. The reduction of total resolved pesticides in the compacted sample, however, cannot

be due entirely to dilution and implies some

sequestration against solvent extraction due to

either microencapsulation or macroencapsulation.

The TCLP test is carried out using an acidic

leaching solution to mimic an acidic landfill environment. Table 9 presents the results obtained on

the “soil-amended Basin F sludge” sample before

and after DCR treatment. These are worst-case

data, in that all TCLP testing on treated waste

13

material was performed on the powdered DCR

product in a noncompacted state. There were no

volatile constituents identified in the leachate of

the DCR-treated soil. The TCLP leachable pesticide data show an even more significant improvement with DCR-treated sample compaction. Significant reductions in leachable aldrin,

dieldrin, and endrin were observed after the initial DCR treatment at 64.7% reagent addition (Table

9). When the reagent addition was dropped to

27.4% and the sample was compacted, even further

reductions in leachable pesticides were observed.

In contrast to the 64.7% reagent addition, these

reductions at the low reagent addition cannot be

attributed solely to reagent dilution of the soil.

Because of the interest in pesticide leachabililty,

these later tests were run in duplicate, and in one

case, the leachable endrin was measured right at

the RCRA limit of 20 ppb. In the other replicate,

endrin was just slightly higher at 28 ppb.

Palmerton zinc smelter study

Table 10 summarizes the total, TCLP-extractable, and water-extractable heavy metal concentrations for the clean soil, the contaminated Palmerton soil, and the DCR-treated Palmerton soil.

The clean soil was, in fact, much cleaner with respect to total heavy metals than the Palmerton

soil. Normal metal ranges for uncontaminated

soils are as follows: Zn = 10–300 μg g–1, Pb = 2–

200 μg g–1, Cu = 2–100 μg g–1, and Cd = 0.01 to

0.70 μg g–1 (Lindsay 1979). By these standards,

the clean soil is a normal uncontaminated soil,

and the Palmerton soil is grossly contaminated.

There were no differences in total heavy metals

between the Palmerton soil and the DCR-treated

Palmerton soil. This is because the DCR treatTable 9. Summary of TCLP leachable constituent analyses on RMA Basin F

soil sample no. 24216 before and after DCR treatment.

64.7% DCR 27.4% DCR 27.4% DCR

Raw waste reagent reagent reagent CA STLC

before addition addition addition regulatory

treatment (loose) (loose) (compacted) limit

Waste constituent (μg/L) (μg/L) (μg/L) (μg/L) (μg/L)

Rep. 1 Rep. 2

Aldrin 52 30 4.0 4.8 n.a. 140

Dieldrin 90 51 31 42 n.a. 800

Endrin 74 44 20 28 20 20

1,2,4-Trichlorobenzene < 1.9 < 1.9 N.A. n.a. n.a.

Hexachlorobutadiene 3.4 J < 1.8 N.A. 500 n.a.

CA STLC – State of California soluble threshold limit concentration.

J – Estimated value; less than the practical quantitation limit.

n.a. – Not applicable.

N.A. – Not analyzed.
ment immobilizes heavy metals but does not physically remove them from the soil. The average total

Zn, Pb, and Cd concentrations in the Palmerton

soil of 29,000 1900, and 160 μg g–1 are somewhat

lower than those cited by Sopper (1989) of 31,000,

5200, and 1250 μg g–1, respectively. Distance from

the smelter and specific location on Blue Mountain

are both critical factors with respect to soil contamination at Palmerton (Buchauer 1973, Sopper

1989).

For the TCLP extracts, the Palmerton soil had

higher concentrations of Zn, Pb, Cu, Cd, Ni, and Se

than either the clean soil or the DCR-treated

Palmerton soil. The Palmerton soil exceeded TCLP

regulatory limits for Pb (5.0 μg mL–1), Cd (1.0 μg

mL–1), and Se (5.0 μg mL–1); this soil passed regulatory limits for Ag (5.0 μg mL–1), As (5.0 μg mL–1),

Cr (5.0 μg mL–1), and Hg (0.2 μg mL–1); regulatory

levels have not been established for Zn, Cu, Be, Ni,

Sb, and Tl (Federal Register, 29 March 1990). The

DCR treatment lowered TCLP concentrations of

Zn, Pb, Cu, Cd, and Se; in all cases, the DCR-treated soil passed TCLP standard for regulated heavy

metals (Pb, Cd, Ag, As, Cr, Hg, and Se).

The Palmerton soil had higher levels of water

soluble Zn and Cd than the DCR-treated Palmerton soil (Table 10). On the other hand, water-soluble Pb and Cu concentrations were higher in the

DCR-treated Palmerton soil than in the contaminated Palmerton soil. The DCR extracts had comparable levels of heavy metals in the TCLP and

water extracts (Table 10). This suggests that the alkalinity of the DCR treatment neutralized the acetic acid used in the TCLP test. During laboratory

TCLP tests, it was clear that the aromatic bite of

acetic acid was missing from the DCR-treatments.

The real comparison between the TCLP and the

water extractions for the DCR-treated soil is probably between a calcium acetate extraction and a

water extraction, which apparently extract similar

quantities of heavy metals.

Because Zn is the dominant heavy metal in

these soils (Table 10), the following discussion will

focus on Zn chemistry. In another report, we also

discuss Cu, Pb, and Cd chemistry in leachates and

plants (Marion et al., in prep.).

The DCR-treatment leachates were alkaline

from the beginning of the experiments, and became progressively more alkaline with time,

reaching pHs in the 11–12 range by the conclusion

of the experiments (Fig. 4). The compacted core

was slower in reaching high pH, indicating some

vertical movement of water around the core. The

clean soil and the Palmerton soil had similar pHs,

in the range 6.2–7.4, until day 61 when the Palmerton soil became more acidic (pH < 6.0).

Zinc concentrations also showed a sharp increase for all treatments on day 61 (Fig. 5). This

was most striking for the Palmerton soil, which

reached 200 mg L–1. In contrast, the levels in the

other treatments were always less than 1 mg L–1.

The DCR treatments were effective in immobilizing Zn in the Palmerton soil.

There were no apparent differences between

plant species with respect to pH (Fig. 4) or Zn (Fig.

5). The responses of perennial ryegrass and tall

fescue were quite similar. Plant roots reached the

experimental soil level by day 50 in all treatments,

approximately 30 days after planting. Shortly

thereafter, there was a sharp drop in pH in the

Palmerton soil (Fig. 4) and a sharp increase in Zn

leaching in all the treatments (Fig. 5). The plant

roots probably acidified the soil increasing the mobility of Zn, especially in the contaminated

Table 10. A summary of the soil analyses for the Palmerton zinc smelter study (mean ± 1 SD; n = 4).

Total metals (μg/g) TCLP extracts (μg/mL) Water extracts (μg/mL)

Element Clean* Contam. DCR Clean Contam. DCR Clean Contam. DCR

Zinc 31 ± 1 29000 ± 816 29500 ± 577 0.21 ± 0.11 588 ± 29 1.9 ± 0.8 0.066 ± 0.014 16 ± 2 1.2 ± 0.8

Lead 5.6 ± 0.1 1850 ± 58 1900 ± 82 <0.31 8.0 ± 0.6 2.2 ± 0.3 <0.30 <0.30 2.4 ± 0.7

Copper 16 ± 1 248 ± 10 252 ± 10 <0.012 0.72 ± 0.04 0.26 ± 0.07 0.014 ± 0.017 <0.012 0.54 ± 0.08

Cadmium <0.51 155 ± 6 160 ± 0 <0.0042 4.0 ± 0.2 <0.0041 <0.0041 0.29 ± 0.03 <0.0041

Silver <1.7 7.0 ± 1.5 6.4 ± 0.1 <0.014 <0.014 <0.014 <0.014 <0.014 <0.014

Arsenic 5.2 ± 0.4 78 ± 5 85 ± 4 <0.45 <0.45 <0.45 <0.45 <0.45 <0.45

Beryllium 0.22 ± 0.01 1.01 ± 0.06 0.94 ± 0.03 <0.00045 0.00053 ± 0.00005 0.00098 ± 0.00015 <0.00045 <0.00045 <0.00045

Chromium 13 ± 1 24 ± 3 21 ± 2 <0.015 <0.015 <0.015 <0.015 <0.015 <0.015

Mercury 0.015 ± 0.006 1.5 ± 0.1 1.5 ± 0.1 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002 <0.0002

Nickel 14 ± 0 29 ± 1 26 ± 1 <0.017 0.12 ± 0.01 <0.017 <0.017 <0.017 <0.017

Antimony <34 <36 <37 <0.30 <0.30 <0.30 <0.30 <0.30 <0.30

Selenium <0.95 8.6 ± 0.4 9.2 ± 0.4 <0.90 7.0 ± 0.4 <0.90 <0.90 <0.90 <0.90

Thallium <0.38 0.42 ± 0.06 0.52 ± 0.06 n.a.† n.a. n.a. n.a. n.a. n.a.

* The soils analyzed were a Charlton silty sand (the clean soil), the Palmerton site soil (contaminated), and the DCR-treated Palmerton site soil.

† Not analyzed.

14
15

Figure 4. Leachate pH as affected by soil treatment, plant species, and time.

Figure 5. Leachate Zn concentration as affected by soil

treatment, plant species, and time.

Palmerton soil. The alkalinity of the DCR treatments neutralized this acidity greatly reducing

the mobility of Zn.

The plant root and shoot properties were analyzed using a two factorial experimental design

with soil treatment (clean, Palmerton, DCR,

DCR-compacted) and plant species (perennial

ryegrass and tall fescue) as the main factors. In

these analyses, the soil treatment-plant species

interaction term was never statistically significant. Therefore, results of these analyses will be

presented by comparisons of the main factors.

Plant shoot, crown, root, and total biomass/

tube were never statistically different among soil

treatments or between plant species (Fig. 6). Despite this lack of statistical significance, there

were clear patterns in both the soil treatments

and plant species. The Palmerton treatment (contaminated) always produced the lowest biomass

with respect to the other three soil treatments.
Figure 6. Plant biomass/tube as affected by soil treatment and plant species. A different lower-case letter within the four soil treatments or the two plant species implies a

statistically significant difference within soil treatments or plant species, respectively.

With the exception of shoot weight, the perennial

ryegrass had higher biomass than tall fescue.

Because of the consistent patterns among soil

treatments (Fig. 6), we also evaluated these treatment means using “contrasts” (Steel and Torrie

1980). For example, we tested the following

hypotheses:

Hypothesis 1

H0: (T1 + T3 + T4)/3 – T2 = 0 (3)

Hypothesis 2

H0: (T3 + T4)/2 – T2 = 0 (4)

where T1 is the clean treatment mean, T2 is the

Palmerton mean, T3 is the DCR mean, and T4 is the

compacted DCR mean.

Hypothesis 1 is a test of whether the Palmerton

mean is significantly different from the other treatment means. For crown weight, we rejected the

null hypothesis at the 5% level of a Type I error.

Relaxing the standard to the 10% level, then Hypothesis 1 would be rejected for all tested plant

properties (Fig. 6). The contaminated Palmerton

treatment was significantly worst than the average

of the other treatments.

Hypothesis 2 is a test of whether the DCR treat16

ments are significantly different from the Palmerton treatment. For this hypothesis, none of the

biomass categories were significant at the 5 %

level. If the statistical criterion is relaxed to the

20% level, then all null hypotheses are rejected for

all four plant properties (Fig. 6).

Overall there were distinct patterns for plant

growth. The perennial ryegrass grew better than

the tall fescue. Growth of plants in the contaminated Palmerton treatment was poorest, and

growth of plants was improved in the DCRtreated Palmerton soil.

Zn concentrations in plant shoots, crowns, and

roots were always highest in the Palmerton soil

and lowest in the clean soil; the DCR treatments

fell between the latter two treatments (Fig. 7).

There were no significant differences in Zn concentrations attributable to plant species. For Zn,

there was a trend in relative concentrations that

fell in the following order: roots > crowns >

shoots.

Element contents in plant compartments (uptake) are a product of biomass and element concentration. For Zn, there were no significant differences in Zn uptake attributable either to soil

treatment or plant species (Fig. 8). Treatments

that were high in Zn concentrations, such as the
17

Palmerton soil (Fig. 7), were low in biomass (Fig.

6). Conversely, the clean soil was high in biomass

but low in Zn concentrations. The consequence of

this inverse relationship between biomass and Zn

concentrations are Zn uptakes that are independent of soil treatment or plant species.

CONCLUSIONS

The DCR process was originally developed for

the immobilization of heavily oiled sludges,

water-in-oil emulsions, oil-contaminated wastes,

and industrial wastes such as acid-tars (Boelsing

1988, 1995). All of these wastes contain liquid

hydrocarbons. Only the three laboratory-scale

tests on Shemya wastes were tests of the efficacy

of the DCR process to stabilize liquid hydrocarbons. The DCR process caused a major decrease

in many monitored hydrocarbons (Table 6). Both

volatilization and Ca(OH)2 encapsulation may

have played a role in the disappearance of these

organic constituents. Lower-molecular-weight

volatile constituents, such as BTEX, are no doubt

lost to volatilization; however, intermediate- and

higher-molecular-weight petroleum hydrocarbons are probably largely sequestered into the

newly formed Ca(OH)2 matrix. The results were,

however, not consistent between wastes, indicating that the specific nature of the wastes will play

a major role in the efficacy of the DCR process to

remediate the wastes.

We also examined two organic wastes that

were solids at the prevailing temperature. One

was the asphalt tar from Shemya, and the other

was the pesticides from Rocky Mt. Arsenal. In

neither case was there a significant overall improvement in chemical properties due to the DCR

treatment (Tables 4, 5, 8, 9). In some cases, there

were actual increases in organic concentrations;

in other cases, reductions in organic concentrations could be accounted for primarily as a dilution effect. It would appear that unless the hydroFigure 7. Plant Zn concentrations as affected by soil

treatment and plant species. A different lower-case

letter within the four soil treatments or the two plant

species implies a statistically significant difference

within soil treatments or plant species, respectively.
Figure 8. Plant Zn contents/tube as affected by soil treatment and plant species. A different lower-case letter within the four soil treatments or the two plant species implies a

statistically significant difference within soil treatments or plant species, respectively.

phobic CaO can readily disperse into the organic

phase, the DCR process is not effective in stabilization of organics.

On the other hand, the DCR process is strongly

dehydrating. Application of the DCR process to

the solid asphalt tar from Shemya produced a

drier, more soil-like, material with hydrophobic

properties. This improved the physical properties

for potential reuse as road subgrade or landfill

covers.

Heavy metal immobilization would seem a

natural application of the DCR technology because many heavy metals form insoluble hydroxides and carbonates (Lindsay 1979). In fact, the

DCR treatment greatly reduced the mobility of

Zn through greenhouse soil columns (Fig. 5). The

acidification of the soil presumably due to root

growth was neutralized by the alkaline DCR

treatment, which greatly reduced Zn mobility.

Adsorption of Zn onto the Ca(OH)2 and CaCO3

and precipitation of Zn hydroxides and carbonates may also have played a role in immobilizing

Zn.

Zn concentrations in plant shoots, crowns, and

roots were always highest in the contaminated

Palmerton soil and lowest in the clean soil; the

DCR treatments fell between the latter two treatments (Fig. 6). No significant differences were apparent in Zn concentrations attributable to plant

species. For Zn, there was a trend in relative concentrations that fell in the following order: roots >

crowns > shoots. Distinct patterns for plant

growth (biomass production) were present in the

heavy metal experiments. The perennial ryegrass

produced more biomass than the tall fescue.

Growth of plants in the contaminated Palmerton

treatment was poorest, and growth of plants was

improved in the DCR-treated Palmerton soil.

Judging by the Zn concentrations in plant tissue

and biomass production, we consider that the

DCR treatment improved plant growth.

RECOMMENDATIONS

Overall the DCR process was successful in stabilizing liquid organics and heavy metals but not

solid-phase organics. Stabilization of liquid organics and heavy metals have been demonstrated

but not under the rigorous experimental design

and statistical testing that were used in our studies. There was an inconsistency between wastes

in the efficacy of the DCR process. This, however,

should not be a serious impediment for the utilization of the DCR process because the efficacy of

18
the DCR process for a specific waste is always ascertained at the laboratory scale prior to field implementation. If the DCR process is ineffective in

remediating a specific waste at the laboratory

scale, then field implementation should not be undertaken.

This work also demonstrated a favorable influence on plant growth of the DCR treatment of

heavy metal contaminated soil. The high alkalinity of the DCR product helped neutralize the heavy

metal mobility, which led to improved plant

growth. This work demonstrated that the DCR

product is compatible with revegetation of contaminated sites and can be used for the remediation of severely contaminated soils, where several

technologies may be necessary to fully remediate a

site.

Following laboratory verification for a specific

waste, we can recommend the DCR process for the

field remediation of liquid organics and heavy

metal contaminated materials.

COMMERCIALIZATION/TECHNOLOGY

TRANSFER

The DCR technologies are patented processes.

SOUND/epic has an exclusive license to market

the DCR technology in the United States. Companies or agencies interested in using this technology should contact Richard W. McManus, Executive

Vice President, at SOUND/epic (214–393–6965).

Our approach in this CPAR project has been to

rigorously test the efficacy of these technologies

and to publicize our results through presentations,

publications, and a video. Below is a list of these

products emanating from the CPAR project. Copies of the publications and the video are available

from Giles M. Marion (603–646–4676). The video

demonstrates a small-scale field implementation

of the DCR process. Although this particular demonstration was not successful because of the solid

state of the contaminant, it does demonstrate how

contaminated soils are processed in the field. Two

presentations of this project (1994 and 1997) were

made at the annual Hazardous Toxic and Radioactive Waste (HTRW) Innovative Technology

Transfer Workshops. These workshops are designed to introduce innovative technologies for

environmental clean-up within the U.S. Army

Corps of Engineers. The presentation at the 1994

Soil Science Society of America meeting and the

ASA Special Publication resulting from this meeting are especially noteworthy for DOD. This was a

Symposium on DOD Cleanup of Contaminated

Sites organized by Dr. C.R. Lee of the Waterways

Experiment Station. This publication should receive

wide circulation within DOD at all management

levels dealing with cleanup of contaminated sites.

Typically DCR stabilization involves either a

direct mixing of reagents and contaminated soil

in-situ (landfarming) or an ex-situ treatment followed by return of the DCR product to the field,

covering with topsoil, and finally, revegetation.

The latter was the process that we simulated in the

greenhouse heavy metal study. The USACE guidance specifications most relevant to the DCR process are Bioremediation using Landfarming Systems

(CEGS–02287) and Solidification/Stabilization of

Contaminated Material (CEGS–02445). However,

neither of these guidance documents speaks

directly to the way in which the DCR process is

generally implemented. Nevertheless, the bioremediation guidance requires that the pH be

maintained in the range from 5.0 to 8.0. This specification may preclude direct landfarming because

of the high alkalinity of the DCR product and

leachate (Fig. 4). The alternative, ex-situ treatment

and covering with topsoil, was compatible with

plant growth (Fig. 6) and presumably microbial

activity. Other than pH, the DCR process is compatible with USACE guidance specifications.

LIST OF PRESENTATIONS, PUBLICATIONS,

AND VIDEOS

Presentations

Dispersion by chemical reaction treatment of asphalt

tar. Contributed paper, Fourth HTRW Innovative

Technology Transfer Workshop. Omaha, Nebraska.

July 1994.

Dispersion by chemical reaction treatment of asphalt

tar, Eareckson Air Force Station, Shemya, Alaska.

Contributed paper, Soil Science Society of America annual meeting, Seattle, Washington. November 1994.

Site remediation via dispersion by chemical reaction

(DCR). Contributed paper, Seventh HTRW Innovative Technology Transfer Workshop. Las Vegas,

Nevada. March 1997.

Heavy metal remediation via the dispersion by chemical reaction process. Contributed paper, Fourth

International Conference on the Biochemistry of

Trace Elements. Berkeley, California. June 1997.

Publications

Brar, G.S., and G.M. Marion (1995) Dispersion by

chemical reaction technology to stabilize asphalt

tar, Eareckson Air Force Station, Shemya, Alaska.

19
USA Cold Regions Research and Engineering Laboratory, Special Report 95–11.

Marion, G.M., G.S. Brar, J.R. Payne, and M.A. Stanka

(1997) Dispersion by chemical reaction technology

to stabilize organic-contaminated soils, Shemya,

Alaska. ASA Special Publication.

Marion, G.M., G.S. Brar, D.K. Pelton, A.J. Palazzo,

and J.R. Payne (in preparation) Heavy metal remediation via the dispersion by chemical reaction

process. Journal of Environmental Quality.

Marion, G.M., J.R. Payne, and G.S. Brar (1997) Site

remediation via dispersion by chemical reaction

(DCR). USA Cold Regions Research and Engineering Laboratory, Special Report 97-18.

Payne, J.R., E.C. Cronick, J.P. Bowman, S.K. Fitzhugh, and J. Bayliss (1994) Dispersion by chemical

reaction (DCR) treatment of asphalt tar: Results of

pilot-scale demonstrations at Eareckson Air Force

Station, Shemya, Alaska. USA Cold Regions Research and Engineering Laboratory, Internal Report No. 1148.

Payne, J.R., and G.M. Marion (1997) Dispersion by

chemical reaction testing of Rocky Mountain Arsenal Basin F waste soils. USA Cold Regions Research and Engineering Laboratory, Special Report

97-3.

Video

 DCR Technology in the Aleutians. 11 minutes. USA

Cold Regions Research and Engineering Laboratory.

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21
August 1997

Site Remediation via Dispersion by Chemical Reaction (DCR) CPAR Project AC910260

Giles M. Marion, James R. Payne, and Gurdarshan S. Brar

U.S. Army Cold Regions Research and Engineering Laboratory

72 Lyme Road Special Report 97-18

Hanover, New Hampshire 03755-1290

Office of the Chief of Engineers

Washington, DC 20314-1000

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The DCR (Dispersion by Chemical Reaction) technologies are a group of patented waste treatment processes

using CaO (quicklime) for the immobilization of heavily oiled sludges, oil-contaminated soils, acid-tars, and

heavy metals in Ca(OH)2 and CaCO3 matrices. The objectives of this project were to 1) evaluate the DCR process for remediating soils contaminated with pesticides, petroleum hydrocarbons (oils and fuels), and heavy

metals in cold regions and 2) evaluate DCR-treated oil-contaminated soil as a non-frost-susceptible (NFS) construction material. Three major studies evaluated the DCR process to remediate 1) hydrocarbons at Eareckson

Air Force Station on Shemya in the Aleutians, 2) pesticide-contaminated soils from Rocky Mt. Arsenal, and 3)

heavy-metal contaminated soils from a former zinc smelter site at Palmerton, Pennsylvania. The DCR process

was successful in stabilizing liquid organics and heavy metals in contaminated soils. The chemical properties

of soils contaminated by solid organics (asphalt tar and pesticides) were not generally improved by the DCR

process, but even in these cases, the physical properties were improved for potential reuse as construction

materials. Following laboratory verification for a specific waste, we can recommend the DCR process for the

field remediation of liquid organics and heavy-metal-contaminated materials.

Chemical stabilization

Contaminated soils

DCR technology

Site remediation