EPA/600/9-85/025
                                                   September 1985
            INTERNATIONAL CONFERENCE

                       ON

  NEW FRONTIERS FOR HAZARDOUS WASTE MANAGEMENT




                   Proceeding

             September 15-18, 1985
                 Pittsburgh, PA




                  Sponsored By
Hazardous Waste Engineering Research Laboratory
       Office of Research and Development
      U.S. Environmental Protection Agency
                NUS Corporation
                 Pittsburgh, PA
           National  Science Foundation
                Washington, D.C.
  American Academy of Environmental  Engineers
                 Annapolis, MD
HAZARDOUS WASTE ENGINEERING RESEARCH LABORATORY
       OFFICE OF RESEARCH AND DEVELOPMENT
      U.S. ENVIRONMENTAL PROTECTION AGENCY
             CINCINNATI, OH  45268

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                                DISCLAIMER
     These proceedings have been reviewed in accordance with  the  U.S.
Environmental  Protection Agency's peer and administrative  review  policies
and approval  for presentation and publication.   Mention of trade  names  or
commercial products does not constitute endorsement or recommendation for
use.

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                                  FOREWORD
     Today's  rapidly developing and changing technologies and  industrial
products and  practices frequently carry  with them the increased  generation of
sol i d and: .hazardous': wastes . ,;- These. mate.ri^lSr:;i f'iniproperly ^ dea-1 th  w th,  can
threaten both"' putfl i c ; heal €lv aYfdrfchev epvTrpnmentvIVe MantiQneo.nfe^t"f1^r
h av e i mp o r tan t ,e nv-.i ro nme ntal ?, and; pub 1 ;i c- :he.a.l t h . g jnp] i cadtiiP ns^ • ; The H a^ar dQ.u s; . ;• :
Waste.. Engnneeringi Research tabo;ratory£assistiS.;ifi:,p;rpyi^ing:\an.;auth0nfeati
and defensible engineering basis for assessing and solyfijig, ithese prob^msxj^nr
Its products  support the policies, programs, and  regulations of  the Environ-
mental Pmtec ti on Agency , ', the permi tti ng- aad oth.eti nesp'ons'i M 1 ^ ti,es:, of. State
and local o governments, and ^tbe-., needs ^ -of  both Jarge alid smalll businesses.--!" n.r^,;:
handl ing-. their wastes responsib.ly an:d.:econ:omlcal'ly. :'.
                   ''
     This  Proceeding- presents the papers  and abstracts* of- presentation's .made .••
at the  International; Conferencer.of.-New' .Froatiar,s;.f.or Hazardous  Waste i  ..-i/H ; t.
Management..  "The.- U:.S. EPA^ NUS' Corporation, c.Nattonal SciancerFoundatioriy'  . '. :
and American Academy of Environmental  Engineers co-sponsored  this conference
in order- to ^summarize important new  technological, developments: and concepts
with broad international application.  ./;.-: ,-.,> •.,.:.   , * ,i;-^-.t>t«,..;) ,:;?./  •)•&  bjinsc:.;-;
                                       David G.  Stephan, Director
                            Hazardous  Waste Engineering Research Laboratory
                                         vni

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                                 ABSTRACT
     The InternationalConference on NewFrontiers for Hazardous Waste
[Management was held In Pittsburgh, Pennsylvania,' September 15-18, 1985.
The purpose of this conference was to examine the state of technology for
the disposal of hazardous waste.  Emphasis was placed on papers that
summarized important new technological developments and concepts with broad
international application.

     Sessions were held in the areas of: (1) Quantification of Health
Hazards, and Definition of Risks,  (2) Land Disposal,  (3) International
Approaches to and Issues Regarding Hazardous Waste Management,  (4) New
Technologies, (5) International Technological Advances,  (6) Extractive
Industries,  (7) Thermal Destruction,  (8) Waste Stabilization,
(9) Nuclear Waste,  (10) Chemical and Biological Treatment Processes,
(11) State/Federal/Institutional Approaches to Hazardous Waste Management.

     This proceedings is a compilation of speakers, papers or abstracts
presented at the conference.  The conference was sponsored by the
U.S. Environmental Protection Agency, NUS Corporation, National Science
Foundation, and the American Academy of Environmental Engineers.
                                    IV

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                            ACKNOWLEDGEMENTS

                            Organizing Board
Allen Cywin
NUS Corporation
Arlington, Virginia
Dr. Raul A. Deju
IT Corporation
Pittsburgh, Pennsylvania
Ronald D. Hill
U.S. Environmental
Agency
Cincinnati, Ohio

Clyde J. Dial
U.S. Environmental
Agency
Cincinnati, Ohio
Protection
Protection
                          Dr. K. T. Thirumalai
                      National Science Foundation
                            Washington, D.C.
                          Organizing Committee
Debra M. Wroblewski
Executive Director
NUS Corporation
Pittsburgh, Pennsylvania
Lynne M. Casper
Assistant Director
NUS Corporation
Pittsburgh, Pennsylvania
                          Supporting Committee

                          Mr. Wi11i am An derson
                          American  Academy of
                        Environmental Engineers
                          Annapolis, Maryland
Joan Berkowitz
A.D. Little, Inc.
Cambridge, Massachusetts

Watson Gin
California Air Resources Board
Sacramento, California

Arata Ichikawa
University of Tokyo
Tokyo, Japan

Dr. Edward S. Kempa
Wydzial Inzynierii Sanitarnej
Wroclaw, Poland

Dr. Michael D. LaGrega
Bucknell University
Lewisburg, Pennsylvania
Andrew F. McClure
NUS Corporation
Pittsburgh, Pennsylvania

Gilbert J. Meyer
NUS Corporation
Pittsburgh, Pennsylvania
David MUler
Geraphty & Miller,
Syosett, New York
Inc.
J.P. Sanstedt
At-Sea Incineration, Inc.
Port Newark, New Jersey

Dr. Joe Touhill
Michael Baker Jr., Inc.
Beaver, Pennsylvania

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                                CONTENTS
                                                                          Page

   SESSION 1 - QUALIFICATION OF HEALTH HAZARDS AND DEFINITION  OF  RISKS


Development in Assessing Risks at Hazardous Waste Sites
     Glenn E. Schweitzer, University of Nevada .....  	    1
Hazardous Waste Risk Analysis:   A New Approach Based On  User-
Interactive Algorithms
     P. Suresh and Aaron A. Jennings, University of Notre Dame ......    7

Subsurface Environmental Emergencies:  Managerial  Requirements
for Excellence
     H. Dan Harman, Jr., and Thomas N. Sargent, Engineering
     Science, Inc.	   15

                       SESSION  2 - LAND DISPOSAL

Restrictions for Land Disposed  Wastes:  Can The Industry Readily Comply?
     Suellen W. Pi rages, Institute of Chemical Waste Management	27

Laboratory Scale Test Simulating Codisposal Landfills
     Artur Mennerieh, Technical University of Braunschweig 	   37

Rapid Appraisal of Relative Risk by Soil Applied Chemicals for
Groundwater Contamination
     Tammo S. Steenhuis and Lewis M. Naylor, Cornell  University  	   46

Physical and Chemical Attenuation Properties of Tidal Marsh Soils
at Three Municipal Landfill Sites
     Steven E. Panter, Richard  Barbour, and Angelo Tagliacozzo,
     Gibbs & Hill, Inc	   57

Land Disposal of Wastes Containing Polynuclear Aromatic  Compounds
     Ronald C. Sims, Utah State University   	  .......   64

      SESSION 3 - INTERNATIONAL APPROACHES TO AND ISSUES REGARDING
                  HAZARDOUS WASTE MANAGEMENT


A New Venture in International  Waste Management
     John Bultin, John A. Bultin Ltd.  .	   72

The United States/Mexico Environmental Agreement of 1983 Bi-National
Hazardous Materials & Waste Management
     Lauren Volpini, U.S. Environmental Protection Agency  ........   73

                                     vii

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Management of Hazardous Wastes Generated by Chemical  Industries
in India
     O.K. Biswas, R.R. Khan and D. De, Department of Environment,
     New Delhi	81

The Bavarian System for Special Waste Management - 15 Years
Experience in Collection, Treatment, Disposal  and Control
     Franz Defregger, Bavarian State Ministry for
     Regional Development and Environmental Affairs,
     Munich, Federal Republic of Germany ..... 	  .  	  82

Hazardous Waste Collecting and Treatment in Austria
     Willibald Lutz and Friedrich Hub!, Consulting Bureau
     for Life, Environment and Recycling, Vienna, Austria   ........  92

Policy Trends in Hazardous Waste Management in Asia and the
Pacific Region
     Nay Htun, The United Nations Environment Programme,
     Bangkok, Thailand 	  100


                      SESSION 4 - NEW TECHNOLOGIES


The Determination of Fixation Treatment Method Limits for
Hazardous Liquids and Industrial Sludges from Disparate Sources
     E. Dennis Escher and John W. Newton, NUS Corporation   	  108

Development and Application of On-Site Treatment Technologies
for Sludge Filled Lagoons
     D.S. Kosson, R.C. Ahlert, J.D.  Boyer,  E.A. Dienemann  and
     J.F. Magee II, Rutgers University	  118

Potential Use of Artificial Ground Freezing for Contaminant
Immobilization
     I.K. Iskandar, T.F. Jenkins, U.S. Army Cold Regions Research
     and Engineering Laboratory	128

Waste Disposal by Hydrofracture and Application of the Technology
to the Management of Hazardous Wastes
     Stephen H.  Stow, C. Stephen Haase, and Herman 0. Weeren,
     Oak Ridge National  Laboratory	138

Design and Installation of a Ground Water Interceptor/Collection
Trench and Treatment System
     Frank J. Vernese, Andrew P. Schechter and Thor Helgason,
     Dames & Moore   	145
                                     vim*

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     SESSION 5 - INTERNATIONAL TECHNOLOGICAL ADVANCES:   AN OVERVIEW


Microbial Detoxification of Cyanide From Wastewater
     N. Shivaraman and N.M. Parhad, National Environmental
     Engineering Research Institute, Nehru Marg,  Nagpur,  India   	  155


Review of Current Practices for Removal  and Disposal  of Arsenic
and Its Compounds in Japan
     H. Kawashima, D.M. Mi sic and M. Suzuki,
     University of Tokyo 	  163

A Decision Model Resulting From the Classification of Hazardous
Waste
     Edward S. Kempa and Ryszard Szpadt, The Technical  University
     of Wroclaw, Wroclaw, Poland 	  171

Hazardous Waste Management Techology in  Italy
     Carlo Merli, University of "La Sapienza",  Rome,  Italy 	  179

Management of Hazardous Wastes in Egypt, An Overview
     Dr. Samia G. Saad and Dr. Hosny K.  Khordagui, High Institute
     of Public Health, Alexandria, Egypt 	  184

                   SESSION 6 - EXTRACTIVE INDUSTRIES


Natural Geochemical Attenuation of Contaminants Contained in
Acidic Seepage
     Jim V. Rouse, J.H. Kleinnfelder and Associates,  and
     Dr. Roman Z. Pyrih, Roman Z. Pyrih  and Associates, Inc	  192

Petroleum Refinery Solid Wastes:  What Will We  Do With  Them?
     Dr. Wayne C. Smith,  Kellogg Corporation  	  200

Ultimate Containment of Residual Hazardous Waste in Salt Formations
     Roger Blair and Fritz Crotogino, PB-KBB, Inc. 	  206

Laboratory and Pilot Plant Assessment of the Acid Production
Potential of Mining Waste Materials
     A. Bruynesteyn and Associates, Mineral Leaching  Consultants	215
     North Vancouver, British Columbia,  Canada

                    SESSION 7 - THERMAL  DESTRUCTION


An Overview of Pi lot-Scale Research in Hazardous Waste  Thermal
Destruction
     Dr. Chun Cheng Lee and George L. Huffman,  U.S. Environmental
     Protection Agency 	  216
                                      IX

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Experiences with Special Waste Reception, Intermediate Storage
and  Incineration ,at the Hazardous Waste Incineration Plant at
Biebesheim
     Gunter Erbach, Hessische Industriemull  GmbH,
     Biebesheim, West Germany	233

Development of Predictive Models for the Assessment of Pollutant
Emissions From Incinerators
     Selim M. Senkan, Illinois Institute of Technology   	  241

Reaction Mechanism of Oxidation of Chlorinated Methanes
     D.L. Miller, M. Frenklach and R.A. Matula,
     Louisiana State University  	  249

Tier 4 Dioxin Test Program Status
     A.J. Miles, R.M. Parks, J. Souther!and, Radian Corporation,
     and D. Oberacker, U.S. Environmental Protection Agency  . 	  250

Thermal Cleaning of Soil Contaminated with Cyanide Wastes from
Former Coal Gasification Plants
     Ed W.B. de Leer, Marian Baas, Corrie Erkelens,
     Daan A. Hoogwater, Jan W. de Leeuw, and P.J. Wijnand Schuyl,
     Delft University of Technology, The Netherlands 	  258

                       SESSION 8 - LAND DISPOSAL


Clay Liners: Where Do We Go From Here?
     David E. Daniel, The University of Texas	  .  266

Thermal Contraction and Crack Formation Potential in Soil
Landfill Covers
     Orlando B. Andersland and Hassan M. Al-Moussawi,
     Michigan State University 	  274

Synthetic Liner Selection and Application To Groundwater Protection
     John D. VanderVoort, Schlegel Lining Technology, Inc	  282

Slurry Wall Materials Evaluation to Prevent Groundwater Contamination
from Organic Constituents
     Ken E. Davis, Marvin C. Herring and J.  Tom Hosea,
     Ken E. Davis Associates	289

Advanced Secure Landfill Design
     Randolph W. Rakoczynski, Waste Resource Associates, Inc	303

De-Gasification of Existing Landfills
    Paul C. Rizzo, Paul  C.  Rizzo Associates, Inc. and
    Carl M. Rizzo, R & R Petroleum, Inc.	312

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                    SESSION 9 - WASTE STABILIZATION


Factors Affecting Stabilization/Solidification of Hazardous Waste
     Jerry N. Jones, R. Mark Bricka» Tommy E.  Myers,  and
     Douglas W. Thompson, U.S. Army Engineer Waterways
     Experiment Station  	 ....... 	  320

A Procedure for Characterizing Interactions of Organics With
Cement:  Effects of Organics on Solidification/Stabilization
     M.E. Tittlebaum, F.K. Cart!edge, D.  Chalasani,
     H. Eaton and M. Walsh, Louisiana State University 	  328

The Rational Use of Cement-Based Stabilization Techniques for
the Disposal of Hazardous Wastes
     All stair I. Clark, Chi S. Poon, Roger Perry, Imperial
     College, London, United Kingdom 	 .......  339

Sorbent Assisted Solidification of a Hazardous Waste
     Tommy E. Myers, Norman R. Francingues, Jr.,  Douglas W. Thompson,
     USAE Waterways Experiment Station, and Donald 0. Hill,
     Mississippi State University  	  348

The Effect of Particle Size on the Leaching of Heavy  Metals
from Stabilized/Solidified Wastes
     Todd M. Brown and Paul L. Bishop, University of
     New Hampshire		356

Development of a Method for Measuring the Freeze-Thaw Resistance
of Solidified/Stabilized Wastes
     P. Hannak and A.J. Li em, Alberta Environmental Centre,
     Alberta, Canada	364

                     SESSION 10 - NEW TECHNOLOGIES


Partitioning Analysis of Chemical Substances as a Tool  for
Managing Hazardous Waste Studies
     Surya S. Prasad and James S. Whang,  AEPCO, Inc.  ...........  377

Recycling and Cleaner Technology as a Means of Hazardous Waste
Management
    Dr. Klaus Muller, National Agency of Environmental  Protection,
    Copenhagen, Denmark  	  .  386

Dewatering of Hazardous Wastes Using Reversible Gel Absorption
     W.J. Maier and E.L. Cussler, University of Minnesota  	  395
                                      XI

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                                                                          Page

Studies on the Biodegradation of Organopollutants by a
White Rot Fungus
     John A. Bumpus and Steven D. Aust, Michigan State
     University	404

Environmental Vault - A New Concept in Land Storage
     William B. Philipbar, Rollins Environmental Services, Inc	411

In Situ Treatment Technologies and Superfund
     Michael Amdurer, Robert Fell man and Sal ah Abdelhamid,
     Ebasco Services, Inc	  415

                       SESSION 11 - NUCLEAR WASTE

Pumping Toxic and Radioactive Fluids with Air Lifts
     Nigel N. Clark, West Virginia University	426

Greater-Confinement Disposal  of Low-Level Radioactive Wastes
     LaVerne E. Trevorrow, Thomas L. Gilbert, Charles Luner,
     Pamela A. Merry-Libby, Natalia K. Meshkov, and Charley Yu,
     Argonne National Laboratory 	  433

Design of Radioactive Tailings Disposal Sites to Last 1,000 Years
     Christopher M. Timm, Jacobs Engineering Group, Inc	  441

A Novel Type of Nuclear Reactor - The Hydro Reactor
     Ge Andlauer, Ener Plan,  Mundelheim, France  	  450

        SESSION 12 - CHEMICAL AND BIOLOGICAL TREATMENT PROCESSES

Extraction of Pesticides from Process Streams Using High
Volatility Solvents
    Stan L. Reynolds, S-CUBED	451

Biological Removal  of Mercury from Toxic Waste
     Jeffrey W. Williams, Conly L.  Hansen and Anish Jantrania,
     The Ohio State University	459

Combined Powdered Carbon/Biological ("PACT") Treatment to Destroy
Organics in Industrial Wastewater
     Harry W. Heath, Jr.,  E. I. du Pont de Nemours & Co., Inc	467

Supercritical Extraction of PCB Contaminated Soils
     B.O. Brady, R.P. Gambrell, K.M. Dooley and F.C. Knopf,
     Louisiana State University  	  479

Microbial Degradation of Polychlorinated Biphenyls
     Ronald Unterman, Donna L. Bedard, Lawrence H. Bopp.,
     Michael J. Brennan, Carl Johnson, and Marie L. Haberl,
     General Electric Company  	  481

                                      xi i

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Radiolytic Dechl on" nation of Polychlorinated Biphenyls
     Ajlt Singh,  Walter Kreraers and Graham S. Bennett,
     Atomic Energy of Canada Limited Research Company
     Pinawa, Manitoba, Canada    	  489

    SESSION 13 - STATE FEDERAL/INSTITUTIONAL APPROACHES TO HAZARDOUS
                 WASTE MANAGEMENT

U.S. Department of Defense Management of Hazardous Waste
     Yearn H. Choi, University of the District of Columbia   	  494

Charting the Course to Enhanced Source Reduction
     Dr. Robert B. Pojasek, Chas. T. Main, Inc	502

Hazardous Waste Management Strategy in Illinois:   Government's Role
     Michael J. Barcelona and Stanley A. Charignon, Jr.,
     Illinois Department of Energy and Natural Resources 	  510

Emerging Toxic Issues for the Electric Utility Industry
     Dr. Ralph Y. Komai, Electric Power Research Institute ...  	  521

The EPA Hazardous Waste Engineering Research Laboratory's
Research Program in Support of Superfund
     Ronald D. Hill, U.S. Environmental Protection Agency  	  523

                    SESSION 14 - THERMAL DESTRUCTION


Surrogate Compounds as Indicators of Hazardous Waste Incineration
Performance
     Robert E, Mournighan and Robert A. Olexsey,   U.S.  Environmental
     Protection Agency 	 ........  	  526

Evaluation of Qn-Site Incineration for Cleanup of Dioxin-Contaminated
Materials
     F. Freestone, U.S. Environmental Protection Agency and
     R. Miller and C. Pfrommer, IT Corporation	531

Hazardous Waste Incineration in Industrial Processes:   Cement
and Lime Kilns
     Robert E. Mournighan and Harry Freeman, U.S. Environmental
     Protection Agency . 	 ................  533

Combustion Fundamental Studies for Hazardous Waste Incineration
     Kun-chieh Lee, Wei-yeong Wang, and Joe E. Neff,
     Union Carbide Corporation 	  ....  550

Fate of Polynuclear Aromatic Compounds During Sewage Sludge
Incineration
     T.R. Bridle, P.J. Crescuolo, and M.J. Bumbaco, Environmental
     Protection Service, Ontario, Canada 	 ...........  560
                                     xm

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           DEVELOPMENTS IN ASSESSING RISKS AT HAZARDOUS WASTE SITES
                             Glenn E.  Schweitzer
                        Envi ronmental  Research Center
                       University of Nevada,  Las Vegas
                           Las Vegas,  Nevada   89114

                                   ABSTRACT

     A number of recent reports by EPA and other organizations  document
available techniques for assessing the risks  associated with  human exposure
to toxic chemicals.  These reports are intended to provide  a  conceptual
framework for risk assessments both at the national  level and in  site-
specific situations.  They are very helpful in considering  general toxi-
cological, epidemiologies!,  and exposure  issues, but they provide very
limited guidance for addressing the types of  situations encountered  at
hazardous waste sites.

     Data limitations severely reduce the usefulness of the formalized
toxicity and exposure assessment procedures advocated in these  reports.
Consequently, the use of action levels expressed as concentration ranges
of pollutants in soil  and ground water and the use of comparisons of chem-
ical concentrations in contaminated and control  areas offer more  practical
approaches as a basis for action.  A review of the risk assessment aspects
of remedial action decisions  at 30 Superfund  sites highlights the difficulty
in standardizing risk assessment procedures.
Trendsin Chemical  Risk Assessment

     Recent studies by the National
Academy of Sciences, the Office of
Science and Technology Policy, and
the National Science Foundation re-
flect the increasing sophistication
that is being advocated for charac-
terizing chemical risk assessments
undertaken in support of regulatory
activities (1,2,3).  Perhaps of
greater significance is the series of
more detailed assessment guidelines
for risk assessments published by EPA
(4).  Also of considerable importance
are the many consent decrees and
judicial decisions directed to reduc-
ing risks under a number of existing
envi ronmental statutes at both the
Federal and State levels.

     The strengths and weaknesses in
using animal studies to predict
health effects are better understood
and more widely recognized than ever
before.  The toxicity differences
among isomers of the same chemicals
are finally being acknowledged.   The
possibilities of chemical trans-
formations of pollutants before  and
after they contact people are in-
creasingly documented.   At long  last
a common lexicon for frequently  used
terms is evolving.  For example,
"exposure" is now recognized to  be
the pollutant concentration at the
body surface where chemical absorp-
tion may occur while "dose" is
differentiated as the concentration
in a critical organ or tissue (5).
Finally, the concept of total in-
tegrated human exposure, including
indoor exposure, is generally
accepted as the basis for estimating
likely health effects.

     Still many aspects of risk
assessment remain elusive.  For
example, the synergistic and antag-
onistic aspects of mixtures remain
but vague concepts.  The significance
of high short-term exposures as   .

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contrasted to low sustained exposures
is not well understood.  An inability
to reconstruct historical exposures
plagues litigation efforts.  Perhaps
most discouragingly even our best
toxicity and exposure models can
never be fully utilized given the
shortage of sound data for such
models.

     Only in a very few cases can we
be reasonably certain of the accuracy
of risk assessments.  The models
being used are helpful in structuring
analyses but rapidly give way to
scientific and non-scientific judge-
ments in providing definitive guid-
ance on corrective actions.

Risk Assessment and Risk Management

     For more than a decade there
have been extensive efforts within
and outside the Government to sepa-
rate the scientific and policy
aspects in determining regulatory
responses to environmental  risks.
Most recently EPA has advocated two
discrete decision processes — risk
assessment and risk management (6).
While such a dual emphasis should
help distinguish scientific facts
from social and economic judgements,
seldom is there a clear distinction
between these two aspects.

     A scientific consensus is lack-
ing on many key points affecting risk
calculations (7).  The details of in-
terpreting data from animal experi-
ments, in particular,  are a constant
source of scientific disputes.  Alter-
native techniques for extrapolating
dose-response curves to low exposure
levels, for example, can result in
risk estimates varying by three
orders of magnitude (8).  Thus, the
choice of the scientific technique
is, in effect, a risk  management
decision.   Similarly,  selections of
other controversial  scientific ap-
proaches which are central  to quanti-
tative  risk assessment should be
considered risk management decisions.

     The establishment of an action
level of 1 ppb for dioxin in soil,
originally to be used at Times Beach
and then used at many other sites,
was clearly a risk management decision
(9).  Its portrayal as a scientific
determination has been very misleading.
There were many uncertainties in the
calculations supporting this number,
and other numbers also could have
been generated from the same scien-
tific data base.  However, the most
important aspect was the disregard of
cost implications in setting this
action  level, since costs are at
the very heart of risk management
decision making.

Uncertainties in Risk Assessments

     Environmental decision makers
are usually reluctant to face up to
the many uncertainties inherent in
risk assessments.  The lawyers warn
that acknowledgements of such un-
certainties can be used by opponents
in efforts to overturn decisions.
Perhaps more importantly, explicitly
displaying uncertainties greatly
complicates the value judgements that
must be made.

     Two of the most common and
largest types of uncertainties are
introduced in toxicological  assess-
ments.  First, as noted above the
type of dose-response extrapolation
that is used dramatically influences
the quantitative estimate.  Secondly,
safety factors are routinely used in
such assessments, as indicated in
Figure 1, and these factors are often
referred to as uncertainty factors
(10).  These types of uncertainties
usually reflect "orders of magnitude"
uncertainties yet they are seldom
highlighted in presenting what appear
to be definitive quantitative esti-
mates of risk.

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    Use a 10-fold factor when ex-
    trapolating from studies on
    prolonged ingestion by man.
    Use a 100-fold factor when ex-
    trapolating from long-term
    feeding studies on experimental
    animals.
    Use a 1000-fold factor when
    extrapolating from less than
    chronic results in experimental
    animals.
    Use an additional factor of 1
    to 10 when deriving an Allow-
    able Daily Intake from a Lowest
    Observed Adverse Effect Level.
Figure 1.  Guidelines for Use of
           Uncertainty (Safety)
           Factors (10).
     With regard to exposure esti-
mates, the greatest uncertainties
are usually associated with popula-
tion activity patterns since personal
dosimetry programs for the general
public do not exist.  Activity pattern
determinations on a retrospective or
prospective basis are always very
crude.  Drinking water and dietary
intake patterns are reasonably well
known, but regulatory efforts seldom
address other types of exposure with
any degree of certainty.

     Also frequenty ignored are the
difficulties in relating exposure to
dose.  The pharmacokinetic data for
determining such relationships seldom
exist.

     The most highly publicized un-
certainty estimates are those asso-
ciated with environmental measure-
ments, uncertainties which are almost
always small in comparison to those
described above.  However, even with
regard to measurement errors, the
focus is frequently misdirected.
Usually, measurement errors center on
errors introduced in the analytical
laboratory, errors commonly in the
range from 10 to 100 percent.   Far
larger errors can easily be intro-
duced through inappropriate designs
of sampling programs or faulty sam-
pling and sample handling procedures.

     The recent EPA guidelines on ex-
posure assessment address some aspects
of uncertainity in very general terms
(11).  While the statistical  tests
that are suggested to address limited
numbers of samples, small  affected
populations, and sparse data for
modelling efforts reflect long over-
due attention to these problems, the
guidance is of limited relevance to
the practical problems of hazardous
waste site assessment.

Action Levels for Soiland Ground Water

     Previous studies have documented
the inadequacy of the traditional
approach of coupling estimates of
human exposure to individual  chemi-
cals with laboratory studies  of the
toxicity of the chemicals as  the
basis for quantitative assessments
of risk when considering problems
near hazardous waste sites (12).  The
inevitable inadequacy of data and the
uncertainties associated with  the
environmental behavior and effects
of chemical mixtures and with  con-
tainment are simply too large.

     A review of 30 Superfund  cleanup
decisions underscores the need for
programmatic and simple indicators
of risk situations (13).  In  not one
case was classical  risk assessment
feasible.  Specifically, action lev-
els for cleaning up soil  and  ground-
water contamination are the key missing
ingredients.  However, in view of the
enormous financial  implications, in
addition to the health and environ-
mental aspects, these action  levels
must be carefully determined.

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     The methodology  for establishing
 an  action level of 1  ppb for dioxin
 in  soil should not be repeated.
 Determination of an action level is a
 risk management decision.  Therefore,
 an  appropriate action  level should
 vary from site to site, and generic
 action levels for individual chemicals
 should be expressed as action ranges.
 For example, the dioxin action range
 might more  appropriately be .1 to 10
 ppb depending on the  type of soil
 which influences dose calculations,
 the location of the site, the likeli-
 hood of child exposure at the site,
 and the cost of cleanup.

     With regard to ground-water con-
 taminants which are already regulated
 under the Safe Drinking Water Act,
 ground-water action levels should
 probably not be the same as the drink-
 ing water standards.   While the stand-
 ards take into account "feasibility"
 considerations, they  are based on the
 feasibility of operating a water
 supply system in a manner that will
 attain the prescribed levels.   Ground-
 water cleanup is a different matter,
 and therefore, different feasibility
 criteria should obtain.  Again an
 action range from a minimum level of
 the drinking water standard to a
 maximum level of perhaps an-order-of-
 magnitude higher might be appropriate.
 The level to be used in a particular
 case would be based on a site-specific
 risk management determination.

 Monitoring Data and Risk Management
 Decisions'

     Since there is little likeli-
 hood that materials balances,  path-
way analysis, or modelling approaches
 will alone provide authoritative in-
 formation concerning exposure  levels
 near waste sites,  monitoring data
 play a central role in risk manage-
ment decisions.   Such  data are used
 in  different ways —  for example,
to determine contaminant levels  of
individual  chemicals or groups  of
chemicals as the basis for "absolute"
risk judgements or to compare con-
taminant levels near sites with
levels in control  areas in deter-
mining "relative"  risks.

     Two types of  "controls"  seem
appropriate.  A control area  with
characteristics similar to the  area
of environmental concern is highly
desirable.   Of special  interest would
be a control area  near the waste
site — but insulated by geographic
features from the  direct influence
of the site.  This area would be
impacted by all of the industrial
emissions and effluents that  permeate
the region as well as other common
sources of contamination such as
agricultural chemicals.  Thus,  in
comparing the contamination near the
site with the contamination in  the
control area, it should be possible
to attribute any higher levels  found
near the site to the influence  of the
site itself and not to the background
characteristics of the region.   A
second type of control can be pro-
vided by national  or regional base-
line data.   Such data indicating
the levels of ambient or background
contamination usually encountered
in different types of demographic
settings can help  clarify the sig-
nificance of environmental  measure-
ments near a hazardous waste  site.

     Obviously, risk assessment data
requirements should be a principal
factor in investigating a waste site.
A combination of assessing absolute
risks associated with selected  chemi-
cals found near the site together
with comparing general  contamination
near the site with contamination in
control areas appears to be the most
feasible approach.  For large or
complicated areas, the sampling plan
should be tied to  a geographic  grid
to facilitate analyses of all con-
tributing sources  and pathways.

-------
     Given the importance of monitor-
ing data, care is needed in imple-
menting monitoring programs.  Figure
2 sets forth a general framework that
should avoid many common pitfalls.
    Objectives must be defined by
    data users at outset.
    Program should be deliberately
    oriented to identifying hot-
    spots and/or assessing long-
    term habitability.
    All monitoring opportunities,
    and particularly pollutant
    pathways, should be examined
    at the outset.
    Statisticians and photo inter-
    preters should assist in de-
    signing program.
    Before any sampling, an over-
    all sampling plan should be
    developed with provisions for
    mid-course corrections.
    20-30 percent of sampling
    should be for preliminary and
    confirmatory sampling.
    Sampling plan should explic-
    itly address previous contro-
    versial findings.
    Alternative sampling sites
    should be pre-selected in
    event of access problems.
    Geophysical investigations can
    help target soil and ground-
    water sampling sites.
    Field and laboratory QA pro-
    grams may account for 15 to 20
    percent of monitoring costs.
    Sample holding times must be
    minimized.
    Since sample contamination is
    frequent, suspect data should
    be revalidated or discarded.
    Approach to data formatting and
    presentation should be jointly
    determined with data users.
    Data quality should be clearly
    differentiated from data
    interpretation.
REFERENCES

 1.  Risk Assessment in the Federal
     Government:  Managing the Proc-
     ess, National  Research Council,
     National  Academy Press, Washing-
     ton, DC,  1983.

 2.  "Chemical  Carcinogens; Review of
     the Science and Its Associated
     Principles, May 1984," Office of
     Science and Technology Policy,
     Federal Register,  Vol. 49,  No.
     100, May  22, 1984.

 3.  Unpublished Documents Presented
     at NSF Meeting of  Experts on
     Risk Assessment, Palo Alto,
     California, July 19-20, 1984.

 4.  See, for  example,  Federal
     Register,  Vol. 49, No. 227,
     November  23, 1984, Pages 46294
     to 46321.

 5.  Wilkins,  J. R., "Exposure As-
     sessment  in Studies of Environ-
     mental  Hazards, An Epidemiologic
     Perspective,"  Toxic Substances
     Journal,  Vol.  5, No.  2, 1984.

 6.  "Risk Assessment and  Management:
     Framework  for  Decision Making,"
     Environmental  Protection Agency,
     EPA 600/9-85-002,  December 1984.

 7.  Davies, Clarence J.,  "Coping
     with Toxic Substances," Issues
     in Science and Technology,
     Winter 1985.

 8.  op.  cit. Wilkins.

 9. "Health  Risk Estimates  for 2,3,
     7,8-Tetrachlorodibenzodioxi n i n
     Soil,"  Morbidity  and  Mortality
     Weekly  Report,  Centers for Dis-
     ease Control,  Vol.  33, No. 3,
     January 27,  1984.
 Figure 2.   Implementing a Monitoring
            Program  (12).

-------
10.  Dourson, M. L. and J. F. Stara,
     "Regulatory History and Experi-
     mental Support of Uncertainty
     (Safety) Factors,"  Regulatory
     toxicology and Pharmacology, 3,
11.
     224-238
        )gy_ and
        (198317
"Proposed Guidelines for Expo-
sure Assessment; Request for
Comments," Environmental Protec-
tion Agency, Federal Register,
Vol. 49, No. 227, November 23,
1984.
12.  Schweitzer, G. E., "Risk Assess-
     ment Near Uncontrolled Hazardous
     Waste Sites:  Role of Monitoring
     Data,"  Environmental Monitoring
     arid Assessment, 2, (T982).

13.  Unpublished Documents of EPA,
     Office of Emergency and Remedial
     Response, 1983-84.
                 Disclaimer

   The work described in this paper was
   not funded by the U.S. Environmental
   Protection Agency.  The contents do
   not necessarily reflect the views of
   the Agency and no official endorse-
   ment should be inferred.

-------
                        HAZARDOUS WASTE RISK ANALYSIS:
             A NEW APPROACH BASED ON USER-INTERACTIVE ALGORITHMS
                       P. Suresh and Aaron A. Jennings
                       Department of Civil Engineering
                           University of Notre Dame
                          Notre Dame, Indiana  46556

                                   ABSTRACT

   The quantification and management of risk is very prominent among the new
concepts in hazardous waste disposal. Risk quantification is an essential
ingredient to wise, long-term waste management. New analytical techniques can
now extract valuable information from an area  that was  once considered to be
too elusive and subjective to measure. Once risks can be quantified, manage-
ment techniques can be implemented to minimize unavoidable dangers, and to
guarantee that risks are equally distributed.

     In this paper we will describe a family of microcomputer-based, user-
interactive risk analysis algorithms based on the Decision Alternative Ratio
Evaluation (DARE)  technique.  It is demonstrated that when the required
pairwise comparisons of technology alternatives are treated as known, a
unique cardinal scale risk rating is produced.  It is also demonstrated that
the procedure may accomodate uncertainty to yield a probabilistic evaluation.
All of the algorithms presented  have been designed for implementation in a
user-friendly programming style. Experience has shown that this helps to
reduce user-intimidation and thereby enhances implementation. This allows
users to come  from a  wide variety of backgrounds  (e.g.,the general  public,
engineers, environmentalists,  politicians,  industrial representatives etc.),
Often, this can provide the positive, constructive involvement required for
innovative waste iranageraent solutions.
INTRODUCTION

The analysis and control of risk  is
one of the most challenging problems
of modern hazardous waste management.
Our past experiences have dramatical-
ly illustrated the consequences of
ignoring risk. Experience has also
demonstrated that new waste manage-
ment  plans  will not be  successful
(i.e.  will not survive  public inspec-
tion), unless the issues of risk are
given serious attention. However,
technological risks  can be very diff-
icult to  assess  given  the vast mech-
anistic and operational differences
between competing hazardous waste
technologies. Risk analysis becomes
even  more elusive when one considers
that  it is  often the "social percep-
tion" of these risks (rather than the
actual risks  themselves)  that
constrain the possible outcomes.

In this paper, methods will be pre-
sented for quantifying the relative
risks of alternative  technologies.
Although these may be used in detail-
ed technical calculations to process
site  specific physical  and chemical
information, they also generalise to
completely subjective "opinionated
preference" analysis.  Therefore,  the
methodology may be used to generate
greater positive  public  involvement
in the issue of risk management.
With this particular application in
mind, the algorithms presented here
have been designed specifically for
user-friendly, user-interactive
microcomputer implementation.

-------
PURPOSE

The risk analyses discussed here can
best be  appreciated in the context
of the specific 'role they are  intend-
ed to play in management  planning.
Jennings  and Sholar(l)  have recently
demonstrated that the mathematical
form of  the  "regional hazardous waste
management problem" subsumes  a trans-
portation  routing optimization. By
this analogy, the "flow" of hazard-
ous materials  is treated as a con-
strained  (forced) mass transfer
through  a network of generation
sources,  processing and storage nodes,
and ultimate disposal  sinks. This
network  concept  is  illustrated
schematically  in fig 1. Note that
links do not necessarily imply sig-
nificant distances. All network acti-
vities could (for example) occur
on-site  at a single industry.
Obviously, the network could also
model the aggregate management
activities of a  large region or
state.
  UULTIPU TTPI
  WASTI CEHEIATIOH
ct
DIRIC1
DISPOSE
\
ULT1PLE
OCISS
LTIUATE
SJX1SAL
ifrsi
.....
t
, WASTI
ASU
KL PROCESS
SPKC1HC
LINKS
WTJ . r

EATMIST |— — i

4. 1 If.
• • T * Si
1
l
y
UNDERFLOW 1
DISPOSAL 1
MULTIPLE
rv PEOCESS
3T8JLATUEJCT
OR
srosAai
    FIGURE 1-Schematic Flow Diagram
    of the Hazardous Waste Management
    Planning Network "Flow" Concept.
Disposal of hazardous materials
requires the undesired movement of
mass  through  this  network (undesired
in  the  sense  that  zero generation
would be the  ideal  solution).  There-
fore, the problem  must be cast in the
form  of a minimization  to reduce the
.total undesired impact.   It has also
been  demonstrated (1)  that these
impacts may be expressed  as  any set
of  penalty functions defined  on
either  the cost or  risk of all
network activities.
One of the substantial complications
in this  network approach is that,  for
general  planning purposes, it  is  de-
sirable  to consider  a wide variety of
waste types  and potential management
technologies. This allows one to iden-
tify  the most valuable treatment and
disposal alternatives and  to generate
sound operating strategies before  mo-
ving  to  detailed implementation plan-
ning. However,  this  requires  that the
potential  network penalties  (costs or
risks) be  evaluated  for  a  wide
variety  of conditions.  This  is  no
easy  task  for either penalty,  but  the
results of several  recent  studies
are now  available to provide  guide-
lines for cost  functions (2,3,4,5).

 It is far more difficult to  identify
risk  analysis procedures  that are
successful in crossing the conceptual
barriers between distinct chemical
waste types  or disposal  technologies.
Procedures can  be  found  (6,7,8,9)  to
rank  (or rate)  the  dangers innate  to
specific chemical groups  (i.e. chlori-
nated organics), or general process
modifications  (i.e.  types of  high
temperature  incineration). Few offer
the flexibility required during
framework planning stages.

The risk analysis procedures  describ-
ed here  are intended to fill  this
void.  They have been designed  speci-
fically  to generate  risk penalty
functions for framework management
planning. They yield cardinal scale
risk  ratings (in arbitrary units of
relative risk)that preserve all the
relative information of  cost  func-
tions. These  methods  also acknowledge
that risk analysis is innately less
accurate than cost analysis. There-
                                      8

-------
fore, the procedures have been de-
signed to account for uncertainty
(imprecision)  and also to yield
information on the confidence that
should be associated with any risk
rating.
APPROACH

 User-interactive methods to extract
 analysis information for risk have
 been constructed from modifications
 of the Decision Alternative Ratio
 Evaluation (DARE)  algorithm of
 Klee(10).  Both RISK1 (a  determinist-
 ic model)  and RISK2 involve a series
 of pairwise comparison of disposal
 alternatives against a set of poten-
 tial consequences to human health -
 and environment as the criteria.
 Klee(10) has  also  demonstrated how
 successive pairwise comparison of
 alternatives yields a cardinal scale
 of relative ratings while keeping the
 number of comparisons to a minimum.

  Briefly,  the DARE algorithm can be
 characterized by  the  following 4
 steps:

 STEP 1:  Selection of M potential con-
 sequences as the criteria for which
 the alternative technologies are to
 be evaluated.

 STEP 2:  Assigning weights for each of
 the M criteria to specify their rela-
 tive importance to the overall analy-
 sis.  These weights may be arbitrarily
 assigned or computed by a DARE analy-
 sis  of potential  consequences.

 STEP 3:  Selection of N hazardous was-
 te management alternatives to be rat-
 ed.

 STEP 4:  Conduction of (N-l) pairwise
 comparisons of  the N management tech-
 nologies (for each of the M conse-
 quences)  to construct a preference
 heirarchy.
Steps 2 and/or 4 may be treated as
being precise (deterministic) or im-
precise due to user uncertainty or
imprecision.

 1.  THE  DETERMINISTIC APPROACH:

 The mathematical formulation to yield
 a deterministic, cardinal  scale risk
 rating  is  as  follows:

 Let W be a Mxl  constrained vector
 containing the  weights of  the M selec-
 ted consequences such that  £ W^ =1.0.
 Let U be a NxM  matrix  storing the
 user -supplied evaluations  such that:

 UNj =1.0  V j=l,M

 Uij 7^0.0  V i=l,N-l; j=l,M.

 A risk  heirarchy matrix H  may then
 be  computed as  follows:
      N
 Hij=
     k=i

 H may then be normalized to yield
 the final rating matrix F.
              V i=l,N; j=l,M
 The final cardinal scale risk rating
 for each alternative may  then be  com-
 puted from H and the weight vector W.
      M
  Ri= E Fijwj   V 1=1,N
 2. THE STOCHASTIC APPROACH:

   The  fundamental techniques  in-
 volved in this  approach  are similar
 to those described  above. However,
 one or more quantities in this ana-
lysis  are considered  to  be fuzzy .
 This leads to a more complicated
 problem structure because  a distri-
 bution of values must now replace

-------
what had earlier been single-valued
elements. To  resolve this problem,
one must select possible values
from each distribution such that
they result in the true upper and
lower bounds  for the  risk values.
By assigning a probability to this
selection, bounds can be calculated
for different  levels of  confidence.
This  procedure is defined as follows:

Let W be a Mxl vector containing
fuzzy weights of the M potential
consequences such that

Wjmin < Wj < Wjmax  v J=1'M-

One must also impose the constraint
that

 M „
It is also necessary to prescribe a
distribution for Wj values between
      and
                           work'
has been assumed  that these are
normally distributed, and contain
the true value of
lity of 0.99.
                   W-; with a probabi
                    J
Now let U be a (NxM) matrix of user
supplied evaluations (Similar to the
deterministic approach).

UNj =1.0  V j=l,M

Uj^j /0.0  V i=l,N-l; j=l,M

Elements of U  may now be any
number  contained by known  bounds.
u
               u
   mn .           max

V  i=l,N-l; j=l,M

Let F be a NxM matrix of final norm-
alized  risk evaluations. The problem
may  now be solved by picking those
                                        values of U^j for each alternative
                                        that result _ in the upper and lower
                                        bounds  of ?i-i.

                                         The selection procedure for U^
                                        values is as follows.
                                        To  obtain    Fiimax' select
                                        (for all i=l,N)  J
                                        uij= i~
                                                      V k=
                                                jmin
                                                      v k=
To   obtain     F
 (for all  i=l,N)
                                                              select
                                        Uij=
                                             'ukjmin
                                              U
                                               kjmax
                                        Using these values of U^^,
                                        the risk heirarchy matn-k H  may be
                                        computed  as before.
                                        Hij=
                                            k=i
                                                       =lrN-l;  j=l,M
It  should  be  noted that this risk
heirarchy matrix must now be calcu-
lated twice (once to calculate
Fijmax  and once to calculate Fijmin),

 The values of these extremes are
computed using the corresponding risk
heirarchy  values:
                                              H;
                                                   V  i=l,N;  j=l,M.
The structure of F and W are
illustrated in figure 2.

Ihe  final  cardinal scale risk rating
R^ for each  alternative can then be
obtained (as before) using the rela-
tion:
  =  1
                                                      V  i=l,N.
                                      10

-------
                   POTENTIAL    CONSEQUENCE
                               i
                                 maz
                                            M
POTENTIAL CONSEQUENCE
                                                            M
                                                                WEIGHT
                                                                    < Wj
           FIGURE 2 - Structure of the fuzzy matrices F and W
In this case however, one must cal-
culate the upper and lower bounds
for RI  using   combinations of
upper and  lower bounds from F^
and W-i.

At a  first glance it would appear
that using all upper bounds
of Wj and F|J would yield an upper

bound on Rj_  while using lower

bounds  would  yield the lower   bound.
However, closer scrutiny reveals that
in sjach a case the weight constraint
£  Wj=1.0 would be violated.

Therefore, in order to select the
combination of weights to yield the
true upper and lower bound on R^_
while satisfying the weight con-
straint, the following procedure is
proposed.
Let
               and
                              be
vectors of extreme F values for the 1th
management alternative written in
decreasing order of magnitude for a
specified degree of confidence (C).  Let
      ^ and W(min)^ be the appro-
                                         priately reordered vectors of minimum
                                         weights for this same degree of
                                         confidence. Also, let us define:

                                         A W j  = {Wj(max)-W.j{min)} V j=l,M

                                           Rem(max)  = E ML (max)  - 1.0
                                                      J  J
                                           Rem(min)  =  1.0 - I W.; (min) .
                                                             j  J
                                         The elements of Aw must also be
                                         reordered to yield AW (max) ^
                                            in)£.  Given these,  the extreme
                                         rankings  may be computed as follows:

                                          R|(max)  = {F(C,max)iTlW(max)i +

                                                                 ]}  V i= 1,N
                                                  = {P(C,min)
                                                                     V i=
                                         where:  W(max)^ is obtained as
                                         follows.
                                    11

-------
       Rem(max)

    j ^AWjOnaxJi => Wj(max)ii=

                         AW.: (max) ^

Renij < iWj(max)^ => Wj (max) ^ = Renu
       ~ Rem-j ~ W^ (max)
Remj+1 < 0.0 => Wj(max)ii = 0.0

                V i=l,N; j=l,M
Next, W(min)ii is obtained as
follows:
   ^ = Rem(min)

Remk >_ iwtminJi => wk(min)ii =

                         ^ (min) i
                 =>
Remk_1 < 0.0 => Wk(min)i;i =0.0

                V k =M,1; i=l,N.

This represents the completion of
one pass of the algorithm. The first
pass values are assumed to represent
the 99% confidence limits. Additional
confidence interval results are prod-
uced by reducing the bounds on the
weight and rating values to represent
different degrees of  confidence.


MICROCOMPUTER IMPLEMENTATION

The algorithm  described above has
been programmed  in FORTRAN 77 for
the IBM Personal Computer. The prog-
ram's user-friendly nature provides
a non-intimidating  atmosphere for
even a first-time  user. It also
helps any user to implement what can
be a  tedious  series  of calculations.
The session starts with the user
selecting the potential consequences
to be  considered  in the  analysis.
This may be  accomplished simply by
making selections  from  the program's
internal menu or by  adding user-
defined consequences. Consequence
weighting  is then accomplished by
either simply assigning weights
or by  conducting  a DARE analysis
on  the consequences themselves.

The next major step is to select
waste  treatment/disposal alternat-
ives to be rated.  Here again the
user is encouraged  to select from
the program's internal menu. The
user may also add  management al-
ternatives. The user is then re-
quired to rate the alternatives
(taken in pairs)  against  all the
consequences  considered.

The program  has been designed to in-
struct the user at every step in the
session.  It has also been protected
(by internal logic)  from non-sequitur
input.  At the end of the analysis
session,  an option is available for
conducting a consistency  check  by re-
ordering all the alternatives and
repeating the rating process.

Results are  printed out at
each  strategic point  in  the session.
A typical risk analysis session
would  last about 15-30 minutes depen-
ding on user familiarity with the
program.  Currently,  efforts are
being made to add an on-line tutorial
session to increase  user awareness
of process operating  modes and poten-
tial failure scenarios.

  The RISK2  source code requires
about 40K bytes of memory. The execu-
table form occupies about  95K bytes.
Results of an example risk analysis
session are presented below.
                                    12

-------
RUN TITLE: EXAMPLE RUN
                                                       THE FINAL RESULTS OF YOUR RISK ANALYSIS ARE f£ FOLLOWS:
A SUMMARY OP THE POTENTIAL CONSEQUENCES
SELECTED IS AS FOLLOWS:

5 CONSEQUENCES WERE SELECTED FROM THE INTERNAL .MENU.
0 CONSEQUENCES WERE ADDED SY THE USER.
THESE RESULTS INDICATE THE LOWER AND UPPER BOUNDS
PREDICTED FOR THE RISK VALUES KITH 99% CONFIDENCE.
NO.
1
2
3
4
5
POTENTIAL CONSEQUENCES SELECTED
SITE WORKER OCCUPATIONAL HAZARD
OFF-SITE ACUTE HUMAN HEALTH HAZARD
OFF-SITE CHRONIC HUMAN HEALTH HAZARD
ACUTE ENVIRONMENTAL DAMAGE POTENTIAL
CHRONIC ENVIRONMENTAL DAMAGE POTENTIAL
MANAGEMENT
OPTION NO.
1
2
3
4
5
6
7
RISK
LOWER BOUND
.063
.072
.093
.114
.187
.172
.136
VALUES
UPPER BOUND
.119
.119
.139
.148
.234
.222
.239
A SUMMARY OF THE WEIGHTING FACTORS FOR THE
CONSEQUENCES IS AS FOLLOWS:
                                                       THESE RESULTS INDICATE THE LOWER AND UPPER BOUNDS
                                                       PREDICTED FOR THE RISK VALUES WITH 95% CONFIDENCE.
CONSEQUENCE
SO.
1
2
3
4
5

LOWER BOUND
.142500
. 180000
.291003
. 170000
.142500
WEIGHT
MEAN
. 150000
.200000
.300000
.200000
.150000

UPPER BOUND
.157500
.220000
.309000
.230000
.157500
MANAGEMENT
OPTION NO.
1
2
3
4
5
6
7
RISK
LOWER BOUND
.374
.081
.102
,121
.197
.181
.149
VALUES
UPPER BOUND
.135
.107
.128
.139
.223
.209
.190
A SUMMARY OF THE TREATMENT/DISPOSAL ALTERNATIVE
SELECTION IS AS FOLLOWS:

7 ALTERNATIVES WERE SELECTED FROM THE INTERNAL MENU.
0 ALTERNATIVES WERE ADDED SY THE USER.
THESE RESULTS INDICATE THE LOWER AND UPPER BOUNDS
PREDICTED FOR THE RISK VALUES WITH 50% CONFIDENCE.
  NO.
        TREATMENT/DISPOSAL MANAGEMENT ALTERNATIVE
        ROTARY KILN INCINERATION
        LIQUID INJECTION INCINERATION
        OCEAN INCINERATION
        SECURE LANDFILL
        LAND TREATMENT
        DEEP WELL INJECTION
        SOLVENT RECOVERY BY REDISTILLATION
MANAGEMENT
OPTION NO.
1
2
3
4
5
6
7
RISK
LOWER BOUND
.083
.090
.111
.127
.205
.190
.162
VALUES
UPPER BOUND
.094
.099
.119
.133
.214
.220
.176
THESE RESULTS INDICATE THE LOWER AND UPPER BOUNDS
PREDICTED FOR THE RISK VALUES WITH 0% CONFIDENCE.
A SUMMARY OF THE USER SUPPLIED PAIRWISE RISK
EVALUATIONS IS AS FOLLOWS:
MANAGEMENT
OPTION MO.
1
2
3
4
5
6
7

1
CONSEQUENCE
2
.85 1.00
.60 .60
1.35
.73
1.20
.50
.00
1.20
.30
1.50
.50
.00
INDEX
3
1.00
1.00
.30
.40
1.00
2.00
.00
NUMBER
4
.90
.85
1.50
1.00
1.00
1.00
.00

5
1.00
1.00
.50
.70
1.38
2.50
.00
MANAGEMENT
OPTION NO.
1
2
3
4
5
6
7
RISK
LOWER BOUND
.089
.094
.115
.130
.209
.195
.168
VALUES
UPPER BOUND
.059
.094
.115
.130
.209
.195
.168
                                                  13

-------
SUMMARY AND CONCLUSIONS

The problem of effective management
of hazardous wastes can be  expres-
sed conveniently as a transportation
"routing" optimization problem. How-
ever,  the penalty functions associ-
ated with the minimization problem
are difficult to evaluate in terms
of intangibles  like risk.  Public
participation in such an evaluation
is recognized to be extremely impor-
tant if management  programs are to be
successfully implemented. Therefore,
a risk analysis procedure (based on
microcomputer technology) has been
developed. This is designed to ex-
tract  quantitative  risk  "opinion"
information from the wide spectrum of
pooplo who must cooperate  in a haz-
ardous waste problem solution.

The information generated  from these
analyses  can also be  used  in deter-
mining the uniqueness of risk values
for a  particular  alternative. This
can  help define the most desirable
hazardous waste management plan; one
which is acceptable from a technical
viewpoint while satisfying con-
straints on actual and public opinion
of  the levels of risk.

REFERENCES

1. Jennings,  A.A. and Sholar, R.L.,
   "Hazardous Waste Disposal Net-
   work Analvsis," J. of Env. Eng.,
   110(2), 325-342,  1984.

2. A.D.Little,Inc.,  "A Plan for Deve-
   lopment of Hazardous Waste Manage-
   ment Facilities  in the New England
   Region, Vol.l,ll, Sept.,  1979.

3. EPA, "Treatability Manual Volume IV
   Cost Estimating," EPA-600/8-80-042d
   July, 1980.
 4. GCA Corporation,  Industrial Waste
   Management Alternatives Assessment
   for the State of  Illinois. Vols.I
   to IV, Nov., 1980.

 5. Jennings, A.A.,  "Profiling Hazard-
   ous Waste Generation for  Manage-
   ment  Planning,"  J.of Haz.  Mat.,
   Vol.(8),69-83,  1983.

 6. Pavoni,  J.L.,  Hagerty,  J.D.,  and
   Lee,  R.E.,  "Environmental Impact
   Evaluation  of  Hazardous Waste
   Disposal in Land," Water  Res.
   Bull.  8(6),  1091-1107,  1972.

 7. Jones,  C.J.,  "The Ranking of  Haz-
   ardous  Materials by Means of  Haz-
   ard  Indices,"  J.of Haz. Mat.,
   Vol.2,  363-389,  1977/78.

 8. Luckritz,  R.T.  and Schneider, A.L.
    "Decision Making in Hazardous
   Material Transportation," J.of Haz.
   Mat.,  Vol.4,129-143,1980.

 9. Wu,J.S.,and Hilger,H.M./'Evalu-
   ation of EPA1s Hazard Ranking
   Syste-n," J.  of Env.Eng. ,110 (4) ,
    797-807,  1984.

10. Klee,  A.J.,  "The Role of  Decision
   Models  in  Evaluation of Environ-
   mental  Health  Alternatives,"
   Management  Science., 13(2),
   B52-B67,  1971.
                   Disclaimer

     The work described  in  this paper was
     not funded by the U.S.  Environmental
     Protection Agency.   The contents do
     not necessarily  reflect the views of
     the Agency and no official endorse-
     ment should be inferred.
                                    14

-------
                   SUBSURFACE ENVIRONMENTAL EMERGENCIES:
                  MANAGERIAL REQUIREMENTS FOR EXCELLENCE

           H. Dan Harman, Jr., P.G. and Thomas N. Sargent, P.E.
                         Engineering-Science, Inc.
                          Atlanta, Georgia 30329
                                 ABSTRACT

    A subsurface environmental emergency such as an underground tank leak,
an underground pipeline leak or an infiltrating chemical surface spill can
be an  incident of grave  concern for industrial or  governmental facility
managers.  No longer is the old cliche "out of sight; out of mind" accept-
able.   A subsurface  environmental emergency  (SEE)  requires  managers  to
literally "see" below the ground surface into what is to many managers, as
well as their corporate or command supervisors, a mysterious environment.

    The first  managerial  problem during  a SEE is  to provide  the  proper
response.  Solutions to this problem rest  in  a manager's  knowledge  of the
specific subsurface problem and who can best respond to solve the problem.
With today's technology, solving an acute ground-water contamination prob-
lem can be as quickly accomplished as solving  an acute  surface water con-
tamination problem.  Therefore the managerial  requirements  are to provide
excellence in  responding  to  site-specific  hydrogeologic conditions  and
excellence in ground-water contamination identification and remediation.

    The other managerial  problem during a SEE  is  to provide satisfactory
performance.  Solutions rest in a manager's knowledge of the specifics for
a SEE investigation.  Satisfactory performance  deals not  only with  how an
investigation is accomplished, but also with the cost-effectiveness of the
investigation techniques.   Investigation  methodologies  such  as  employee
interviews, review  of  site history,  immediately available  data  acquisi-
tion, and use of appropriate investigation techniques are essential for a
manager to understand.   A manager should  also  understand the  cost-
effectiveness of one technique  versus  another.  An example would  be  how
cost-effective a remote sensing  technique might be  versus  an exploratory
drilling program.  Therefore a manager must assure  not  only excellence  in
investigative methodology and data  acquisition  techniques but  also  in
controlling expenditures.

    An essential part of  the successful performance  of  a  task is  assuring
that an understandable  report is prepared which  results  in  corporate  or
command acceptance of  the report.   A  report should address  the  critical
items of the SEE in the proper perspectives.
                                    15

-------
     This paper  presents  managerial requirements  for  excellence during  a
 subsurface  environmental  emergency.   Since  a  SEE response  requires  a
 timely reaction,  prior knowledge  of  methodologies and  techniques and  a
 standard operating protocol are essential for managerial excellence.   This
 paper specifically outlines for the manager procedures  for  SEE  responses,
 performance and  reporting.  In addition specific  examples of excellence in
 understanding subsurface  and  contaminant migration  characteristics are
 cited.
 INTRODUCTION AND PURPOSE

     A   subsurface    environmental
 emergency such  as  an  underground
 tank leak,  an underground pipeline
 leak or  an infiltrating  chemical
 surface spill can  be an  incident
 of grave concern for  industrial or
 governmental facility managers.  A
 subsurface  environmental   emergency
 (SEE)  requires managers to  liter-
 ally   "see"   below  the   ground
 surface  into  what  is   to  many
 managers  as well as  their  corpo-
 rate  or  command  supervisors   a
 mysterious  environment.   Since  a
 SEE response  requires  a  timely
 reaction,    prior   knowledge    of
 methodologies  and techniques and a
 standard  operating procedure   are
 essential  for  managerial  excel-
 lence.   The  purpose of  this paper
 is   to  outline  for  the  manager
 procedures   for  a  SEE  response,
 performance   and  report.      The
 generalized    procedural   outline
 discussion  is  followed  by a dis-
 cussion of  specific  examples of
problems  and  solutions   in under-
 standing  subsurface  and  contami-
nant migration characteristics.

GENERALIZED PROCEDURAL OUTLINE

    As  a  facility  manager  plans
his  or her program dealing with
subsurface   environmental   emer-
gencies,  there  are  three  major
areas   with   which   the   manager
should  be concerned.  These three
areas are the response to the SEE,
the   performance   of   the   SEE
investigation   and   the   report
following the SEE.  The managerial
requirements  for  excellence begin
with  the  necessity to  plan ahead
in    establishing   a    standard
operating   procedure    (SOP)   for
subsurface  environmental  emergen-
cies .  For  best results an  SOP is
essential during each of the three
areas of concern.

    The  critical   elements   which
should be addressed within  an SOP
for a SEE response ares

    Facility
       Waste Handling and/or
         Storage Areas
       Petroleum,  Oils & Lubri-
         cants (POL)  Areas
       Underground Utilities

    Federal  Regulations
       Resource Conservation &
         Recovery  Act
       Toxic Substances  Control
         Act
       Conservation and  Environ-
        mental Resource Control  &
         Liability Act
       Safe  Water  Drinking Act
       Leaking Underground Storage
         Tank Regulations
         (Proposed)

    State  Environmental
       Regulations
                                   16

-------
    Local Environmental
       Regulations

    Geological Characteristics
       Regional
       Vicinity
       Facility
    Ground-water Characteristics
       Regional
       Vicinity
       Facility

    Investigation Methodologies
       General Knowledge
       Availability of Specialists
       Specialists in Specific
         Fields
          Geology
          Ground Water
          Geophysics
          Remedial Actions

    Response Time

    Public Relations

    Corporate or Command
      Involvement

    The  critical  elements  which
should be addressed within an SOP
for the  performance of  the  SEE
investigation are:

    Timely Reaction
       Mobilization
       Efficiency
       Daily Reports

    Employee interviews
       Insights to Cause and
         Effect Relationships
       Potential Sources of SEE
       Confirming Data

    Facility History
       Past Activities
       Past and Present Activity
         Relationships
       Land Use Characteristics
    Analysis of Available Data

    Investigation Methodologies
       Specific Techniques
         Applicability
         Confidence in  Technique
         Confidence in
           Specialist
         Assurance of Performance
         Cost Effectiveness
         Budget

    The  critical  elements  which
should be  addressed  within an SOP
for a SEE report are:

    Interim Reports
       Daily
       Constant Re-evaluation
       Recommendations

    Draft Report
       Concise
       Executive Summary for
         Corporate or Command
         Reviewers
       Specifics for Regulatory
         Reviewers
       Recommendations

    Final Report
       Appropriate perspectives
       Precise
       Inclusion of Unanswered
         Questions
       Recommendations

SPECIFIC EXAMPLES

Environmental Consultants

    Within above  generalized out-
line a manager will  probably have
the most problems  with geological
and  ground-water  characteristics
as well as investigative methodol-
ogies .    Geological  and  ground-
water  characteristics  can  normally
be    understood    by    reviewing
                                   17

-------
 federal,  state and  local hydro-
 geological  reports.    Investigative
 methodologies    are     generally
 described  in  appropriate   textbooks
 and professional journals,  but the
 application of  these methods  may
 or may  not be  effective  in  all
 facility SEE investigations.   For
 a manager to effectively manage a
 SEE  investigation   the    manager
 should   consult  professionals  in
 specific   fields   of    interest.
 These may include -

     Hydrogeology
     Geophysics
     Monitoring Well Drilling
     Remedial  Actions

 A consultant  which offers  services
 in all of  the  above professions
 may be the  most  cost-effective  for
 the facility  manager.     Then  a
 problem arises  when the  manager
 learns that many consultants offer
 all  of   these  services.     The
 managerial     requirement     for
 excellence then becomes  one not
 only  of  judgements of  investiga-
 tive methodologies  but  also and
 perhaps  more importantly  one of
 judgements of individuals.  Indiv-
 iduals   comprise   a   consulting
 company  and  individuals will per-
 form  the   investigation   at  the
 facility.   Therefore, knowing the
most about individuals  and their
application  of  professionalism  and
investigative  methodologies  offers
the  facility  manager the  highest
degree of excellence in the  re-
sponse,  performance and  reporting
of  a particular SEE.  Knowledge
about individuals can be  obtained
by evaluating:

    Resumes

    Professional Affiliations
     Meetings
        First  Impressions  .
        In-Depth Conversations
        Senario Presentations

     References
        Personal
        Previous Day-to-Day
          Contacts with Other
          Facility Managers

 Electrical Resistivity

     Electrical resistivity (ER> is
 one  of  the   most  cost-effective
 investigative   methodologies  that
 can  be  applied during a  SEE.   One
 technique of   ER which  has  proven
 to  be   very   helpful   and  quite
 revealing in SEE investigations is
 the   "Modified  Wenner   Array."
 Figure   1  illustrates  the  metal
 probe or electrode  set-up in  this
 array.   An electrical current from
 batteries is conducted through the
 ground  via the outer  probes  and
 the resulting voltage potential is
 measured  via the inner  probes.  In
 the  "modified  Wenner  Array"  the
 inner  probe distance  across  the
 ground  surface has  been  found  to
 be  very  close  to  the  depth  of
 investigation  below  the  ground.
 Therefore,  a  manager   may  "see"
 within  the subsurface through  the
 eyes, experience and knowledge  of
 a  trained user of  ER.   Figures  2
 and 3 are two  examples of  how  well
 ER corresponds  to  actual subsur-
 face  conditions.    Note  how  in
 Figure  2  the ER interpretation  of
 the depth to   the top of  consol-
idated  rock   is similar  to   the
ac tua1 depth.

    In Figure  3 note how  the  sand
zone between  52 and 58  feet  is
depicted by ER and how similar  the
ER and  actual  top  of rock depths
                                  18

-------
 are   illustrated.      The   cost-
 effectiveness   of   ER  can   be
 realized by the proper  application
 of ER to  specific hydrogeological
 conditions.       An    exploratory
 drilling   program   designed   to
 gather  the  same  amount of subsur-
 face   data   would  be   far  more
 expense than  properly   interpreting
 many  ER measurements with  only a
 minimum number of test  borings.

    ER  can   be   used  to  detect
 ground-water  contamination  as  veil
 as to depict  hydrogeological con-
 ditions .  Figures 4 and 5 are two
 examples of how ER can  be used to
 detect  ground-water  contamination.
 Figure 4 illustrates the detection
 of a  localized  area  of contam-
 ination where as  Figure  5  illus-
 trates  the detection  of ground-
 water  contamination  over a  broad
 area.

 Monitoring Well Construction

    Within  the performance  of a
 SEE  investigation  monitoring  wells
 will  more  than likely  be needed.
 Wells should be located upgradient
 and downgradient of  the suspected
 source  of   contamination.     As
 stated earlier ER is  an excellent
technique    to  utilize  in   the
placement   of  select   monitoring
wells.  Placement  of wells as well
as  their   construction  are  very
critical elements in a  SEE inves-
 tigation.   The design requirements
of a well  are factors such as -

    Drilling Logs
    Hydrogeological
      Classifications
       of  Strata
    Well Materials
    Seals
 The above factors are  illustrated
 in Figure 6.   A well written  dril-
 ling  log  is  simple  to  understand
 and easy  to visualize.   The hydro-
 geological   classifications    are
 normally  straight-forward as  seen
 in Figure 6.   Well  materials  are
 based  on  the contaminant charac-
 teristics  and  the  depth  of  the
 well.  In  the illustrated case,
 metal    contamination    in    the
 confined  aquifer was  of concern.
 Polyvinyl  chloride   casing   and
 screen    was    selected   because
 organics   were  not   of  concern;
 four-inch  diameter  was  selected
 because of  its  ease  of development
 and because  the  client preferred
 to use   a  submersible  pump   for
 purging and sampling.   Well seals
 of bentonite, cement grout  and a
 locking  cap  insure  the integrity
 of,the well.

 CONCLUSION AND  SUMMARY

    Subsurface  Environmental   Emer-
 gencies are  of grave concern to
 industrial and  governmental  facil-
 ity managers.   Managers must "see"
 below their  facilities  into the
 subsurface to insure excellence in
 responding,  performing  and  report-
 ing   of    subsurface   problems.
 Numerous factors may contribute to
 the   effectiveness   of   a   SEE
 investigation,  but  very few are
 effective  without prior  planning
 and an  established standard oper-
 ating protocol.

    The    two    most    important
 requirements for a manager to meet
 during a SEE are  (1)  to understand
 those  who  respond,   perform  and
 report  to him  or her and  (2) to
 realize     that    cost-effective
 techniques  such  as   electrical
resistivity  can  be  applied  to
yield critical data in the highest
                                   19

-------
expectations    of   investigative
excellence.

REFERENCES

1»  Carrington,  T.J.  and  D.  A.
    Watson,   Preliminary  Evaluation
    of   an   Alternate   Electrode
    Array  for  Use   in   Shallow-
    Subsurface  Electrical  Resis-
    tivity Studies:  Ground  Water
    - January - February,    1981,
    Vol. 10,  No. 1, 1981.
               Disclaimer

 The work described in this paper was
 not funded by the U.S. Environmental
 Protection Agency.  The contents do
 not necessarily reflect the views of
 the Agency and no official endorse-
 ment should be inferred.
                                  20

-------
Formula for Apparent Resistivity FIGURE 1
._/n_^r 1 1 "MODIFIED WENNER" ARRAY
p v*.nrU ^
///////,
SOURCE: Carrlngtoi
/r - 1/r - 1/rg+ 1/r UIAUHAM Uh bLhU I HUUh 5PAUINU
Current Meter Battery
®l ih
II
Volt Meter
C P P' C'
///////////// / ////////////////// 7 T / ////
	 	 	 fe. ^ 1» , ,, 	 .,,!.*.«
1 ^ »2
! 1
^ •• w. -• »• 	 	 ^1
^ «3 * * r4 *
i & Watson, 1981

-------
   10 --
   20 --
   30 --
                  APPARENT RESISTIVITY  (ohm-ft.  x 10)
                   150  200  250  300  350  400  450  500
                      CLAY,SIL
                         & SANE
          7.5 ft. WATER TABLE
                  DRY (INTERPRETATION)
    !WATER TABLE 8 ft.
    \CINTERPRETATION)
                  CONSOLIDATED ROCK
                (INTERPRETATION)^
                                                   CLAY, SILT
                                                     & SAND
                              30.3 ft. CONSOLIDATED
                                          ROCK
o
§50 +
Q_

Q_
   60 --
  70--
  80 --
  90--
                         FIGURE 2
                     GLACIAL TILL
       VERTICAL ELECTRICAL SOUNDING
APPARENT
RESISTIVITY
GRAPH
                                           NOTE:
CUMULATIVE
RESISTIVITY
GRAPH
                                    TEST BORING IS
                                    218 FEET WEST
                                    OF SOUNDING.
 100 -L
     0    50   100   150  200   250   300   350   400
              CUMULATIVE RESISTIVITY (Ohm-ft.  x 102)
                                         450   5CC
                                22

-------
120--
140 --


160 —


180--


200 --
  •  0
              APPARENT RESISTIVITY (ohm-ft. x 10)
          100     200    300    400    500
                                               CLAY
                                    WATER TABLE SILT
                             lg (INTERPRETATION) SAND
                                               	42 f
                                           FINE SANDY SIL
                              54 ft.
                              58 ft.
                                             WEATHERED
                                               ROCK
  FRACTURES
(INTERPRETATION)
                                     TOP OF HORNBLEND
                 CONSOLIDATED
                     ROCK  86 ft
                    BIOTITE SCHIST
                            MODERATE WATER LOSS
               (INTERPRETATION)
                              TEST BORINc IS 16c
                              FEET NORTHEAST OF
                              SOUNDING.
                              FIGURE 3
              CRYSTALLINE ROCK  OVERBURDEN
              VERTICAL ELECTRICAL SOUNDING
             APPARENT
             RESISTIVITY
             GRAPH
                CUMULATIVE
                RESISTIVITY
                GRAPH
        200   400   600   800  1000  12.00  1400  1600  18CI  ZOOC
             CUMULATIVE RESISTIVITY (ohm-ft. x 102)
                               23

-------
                  APPARENT RESISTIVITY (OHM-FEET)
           N
           o
           o
  O
  O
O)
O
O
O3
O
O
O
O
o
to
o
o
o
o
en
o
o
o
o
o
o
o
7
TJ
M

3
o
>-«

a
                     Apparent

                     Resistivity

                     Graph
        Cumulative

        Resistivity

        Sraph
                            FIGURE 4

                        DETECTION OF

                       CONTAMINATED

                       GROUND-WATER

                     ZONE BY VERTICAL

                          ELECTRICAL

                           SOUNDING
                       50 feet
                              SILTY SAND

                            (interpretation)

                               60 feet
              contaminated zone

               (55 to- 60 feet)
   CD
   O
   (O
   o
   g
        NOTE:
Well is 130 Feet North of

Resistivity Sounding.
          c
          o
               c
               c
               c,
      ro
      K*

      a
    ro
    CD
    o
    o
    c
    en
    c
    o
    a
                     o
                     a
                     G
         (O
         c
         c
         c
         Ul
         O)
         o
         a
         c
         03
         CO
         o
         c
         c
         c
         c
                 CUMULATIVE RESISTIVITY (OHM-FEET)
                             24

-------
   \       FIGURE 5
APPARENT RESISTIVITY
    \ PROFILE MAP
   (ELECTRODE SPACING
       OF 60 FEET)
                In ahin-fwrf
                froffl* Slatiw met
                Profll* Stfttmr mtt v«u
                <300
   25

-------
                             FIGURE 6
                           TYPICAL
   MONITORING WELL  CONSTRUCTION
      STEEL CAP

       LOCK.

   8* PVC CAP


6" STEEL CASING



  ,« pvC CASING



7 7/8" BOREHOLE




 CEMENT GROUT
2,5' BENTONITE SEAL
     GRAVEL PACK
   *« PVC SCREEN
   SLOT SIZE e.OIS'
  1" PVC BACK-WASH
  VALVE
 V BENTONITE SEAL

    DRILL CUTTING
    BACKFILL
   TOTAL DEPTH
,^S

LE 	
fT i •

L 	

K 	
H

L-* 	 '

!=«



^

***£
i
it
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| 	 ____

                            tAND
                            .W.L.
                              u
                                 35.
                               0
                               z
                                 US-
                               s
                               o
                                           DRILLING LOG    CLASS"CATIONS
                                    CLAY, MULTICOLORED, WHITE. RED.
                                    BROWN
                                    SAND, MED. TO COARSE GRAIN,   U%Cr>
                                    BROWN TO YELLOW; MICA       AC."
                                    CLAY. SANDY. YELLOW-RED
                                     FINE TO MED. GRAIN.
                                SILTY, YELLOW-WHITE, MICA;
                                DARK MINERAL SPECKS
                                                          ACl. ==3
                                CLAY. SILTY, BROWN-REO WITH CRAr
                                STREAKS; SAND, FINE GRAIN, SILTY
                                BROWN (SOW
                                    CLAY, GREEN-GRAY WITH BROWN
                                    STREAKS; VERY LITTLE SILT OR
                                    SAND; VERY DENSE AND HARD
                                 26

-------
                   RESTRICTIONS  FOR LAND DISPOSED WASTES:
                      CAN THE  INDUSTRY READILY COMPLY?
                             Suellen W, Pirages
                   Institute  of  Chemical Waste Management
                          Washington, D.C.  20036

                                 ABSTRACT

     Congressional  legislation now  mandates the restriction of certain
hazardous  wastes  from land disposal.   Although government  officials and  the
public have  assumed  that such restrictions  can  be implemented, the capability
for rapid  implementation has not been  evaluated.  According  to EPA  data, most
of the annual  volume of  hazardous waste generated  already receives some
treatment.   Only 20 percent of this annual  volume is disposed in the land  and
very little  actually is placed in landfills (only 1 percent of the total
volume).  Current commercial capacity is limited,  representing only  one
percent of the total  unused capacity throughout the  country.

     A broad  range of technologies  exist now that can completely destroy  or,
at least,  reduce hazards  associated with industrial  wastes.  New technological
developments  make  it possible to  treat effectively mixtures  of organic  and
inorganic  wastes  and to  degrade  previously recalcitrant constituents.   Rapid
commercial development  of these alternatives  to land disposal,  however,   is
hampered by certain  barriers.   Currently,  there is  considerable difficulty in
siting new treatment facilities.   Regulatory  standards  are  not  available  by
which the  effectiveness and efficiencies of new developments can  be evaluated.
As the goal of waste minimization is  achieved,  there will be uncertainties in
the size and composition  of  future markets.   Finally,  the  current  oace  and
priorities of the federal  and  state  permitting process  delays  expeditious
commercial development.   Until more  efficient  institutional  mechanisms  are
developed  to reduce  these barriers,   commercial  capacities  to  manage  land-
restricted wastes may not  be sufficient.
INTRODUCTION

     The  goal of the federal  hazardous
waste management program  is  to  reduce
dependence  on  land  disposal   as  a
predominant  management option.   Thus,
the  Hazardous   and  Solid   Waste
Amendments (HSWA)  of 1984  include the
mandate  that the U.S.  Environmental
Protection Agency  (EPA) must evaluate
all  hazardous waste streams and
determine which should be  restricted
from land disposal.   The Amendments
establish  deadlines   (one-third  by
1988,  a  second-third by 1989 and all
by 1990) for such  restrictions;  if
these  are   missed,  automatic
prohibition of hazardous wastes  in any
land disposal  facility will  results.
There is  some concern about the  timing
of these schedules  and  the  ability of
EPA to make  timely  decisions about
specific  wastes.  Of  major  concern is
not whether  alternative  technology
exists,   but  whether commercial
facilities are available  to handle
these  wastes.

    This  paper reviews generation and
disposal   data,   identifies  and
discusses the  capacity of available
commercial   facilities.     New
technologies   are  reviewed  noting
implementation  barriers.
                                    27

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Generation  and Management  Data

     In the 1981 survey of hazardous
waste  generators and waste  service
facilities  prepared for  EPA,  it  is
estimated that 265 million metric tons
of  hazardous  waste  are  generated
annually.(9)  Although 84 percent of
all  generators  use  the  commercial
waste  service industry for treatment
and  disposal  of their wastes, most
hazardous  wastes (96 percent of  the
annual  volume) are managed at the site
of generation or in generator-owned
facilities.  According to EPA data,
the  total  number  of   commercial
facilities (including  treatment,
storage incineration and  disposal)  is
326.   EPA defines commercial as those
facilities  that  receive more  than  5n
percent of the wastes from other firms
and are privately owned and operated.

     This survey also indicates  that
most wastes are treated in some manner
(66 percent  of the  total  volume).   In
addition,   EPA  found that only  20
percent  of all   hazardous waste  is
placed  in  land  disposal  facilities.
EPA defines  land disposal  very broadly
and  includes  underground  injection
wells,  surface  impoundments, land
treatment,  waste  piles, and landfills.
Of  these  types  of  land  disposal,
injection wells are most commonly used
and surface impoundments  second most
common.  Only 1  percent of the total
volume of hazardous waste  is placed in
the 199 landfills found throughout  the
United  States.

Commercially Available  Alternatives.

     There  are five  major types of
treatment alternatives practiced  in
the hazardous  waste service industry
today.   These   include   physical,
chemical,  biological, thermal  and
stabilization/solidification treatment
processes.   The acutal application  of
any one, or any combination of these
five,  depends on characteristics  and
properties  of the  waste  (i.e.,  is  it
solid,  liquid,   concentrated  or
dilutes?).
      Physical treatments only separate
 various phases  of the waste  (e.g.,
 liguids from  solids) and,  in general,
 concentrate hazardous  constituents in
 solid   or  sludge  phases.    By
 concentrating  the  consitituents ,
 further treatment processes or perhaps
 direct  disposal  can  be  done  more
 conveniently.   Chemical  treatments
 involve advanced chemical reactions
 that  will either render the waste non-
 hazardous,    e.g.,   through
 neutralization,  or completely destroy
 the hazardous compounds, e.g., through
 hydration.   Likewise,  biological
 treatments can  destroy or,  at  a
 minimum,   reduce  the  hazardous
 concentrations  within  the waste.
 Thermal  destructions usually involve
 combustion of organic  material into
 carbon,  oxygen,  and water.    It must
 be  emphasized  that all  of  these
 treatment processes generate  a residue
 that  may be of  lesser,  or  greater,
 hazard potential and may be in volumes
 greater than  the  original  waste.
 These  residues  can only  be^ 1 and
 disposed.

     A review conducted by Mackie  and
 Niesen  indicates  that there  is  a
 diverse  range of treatment  options
 commercially available.(5)   Table   1
 illustrates  some  typical applications.
 Within the  area  of physical treatment
 there are magnetic processes, liquid-
 solids  separation,  and membrane
 separation  techniques such as reverse
 osmosis and electrodialysis.

     Chemical treatment alternatives
are  not  new.  The technical ability to
chemically  neutralize or  change
industrial  waste  has  been  availabale
for many years.   Innovation focuses
primarily on new applications and on
the  development of more efficient, uses
of chemical  reactions.   Commercial
applications  include  oxidation-
reduction reactions  to  degrade  trace
organics,   photolysis  to  destroy
cyanide and  dioxin  wastes,  and
precipitation  of  various  metals.
Major considerations  in the use of
these  types of treatment processes  are
                                    28

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TABLE 1.  EXAMPLES OF COMMERCIALLY AVAILABLE TREATMENTS
Physical

  Centrifugatlon
  Filter Presses
  Distillation
  Carbon Absorption
  Reverse Osmosis

Chemical
  Precipitation
  Oxidation
  Reduction-dechlorination
  Photolysis

Biological

  Aerobic/Anaerobic
  Land Treatment

Thermal
  Liquid Injection
  Rotary kiln

Stabi1ization/Solidlfication

  Sorption
                              Typical Applications
separates liquids and solids
removes moisture from solids, sludges
solvent purification
removes organics
removes metals and organics
removes metals
destroys organics
reduces chlorine content of hydrocarbons
destroys dioxin and cyanide
removes metals and organics
degradation of organic sludges
destroys organics in liquid wastes
destroys organics in sludges and solids
  Pozzolanic Reactions
uses variety of material to solidify
inorganic liquids  (e.g.,  fly  ash, lime,
clays and carbon)

uses lime-fly ash or portland cement to
solidify inorganic wastes.
                                29

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the potentially low solubility of some
metals,  Impurities in the waste that
can inhibit  reaction,  and potentials
for generating equally hazardous  by-
products.

     Biological  processes  have been
used in public  wastewater treatment
systems  for  sometime.  The limitation
of  these  treatment  applications,
however,   is  the  presence   of
biodegradable constituents in  a waste
stream.   Biological  reactions  are
quite sensitive to the  presence  of
toxic   elements,   either  non-
biodegradable organic compounds  or
metals.   Land  treatment  is a  form of
degradation used  commercially for some
hazardous waste, primarily refinery
sludges.  However, using  this process,
the potential  exists  for incomplete
degradation  by natural microorganisms
and migration  of   hazardous
constituents from the treatment site
to groundwater sources.

     Conventional thermal treatment
processes (traditional  incineration)
are  useful  primarily  for  organic
compounds.    These   treatment
alternatives can be quite  efficient,
but also very expensive by comparison
with physical, chemical or biological
processes.   There are limitations  in
the  fuel  value  of a waste   and  in
operational conditions  required for
maximum  destruction efficiency.


     Stabilization/solidification
processes are alterntives used  for
wastes  containing inorganic elements.
In contrast  with chemical, biological
and thermal treatments, there is no
change  in the toxic property  of the
hazardous  constituent.   However,  the
potential   mobility   of   these
constituents  often   is  reduce
dramatically.    Although  these
treatment  processes are  commercially
available, new applications are being
investigated.   For example,  a  joint.
research effort is underway  between
Canada  and  the  United States.(6)  The
purpose is  to  evaluate  the range  of
stabilization/solidification processes
and the  integrity of  these for  a
diverse range of wastes.

New Te c h n o 1o g i c a 1 Ap p1 i c a t i on s

    No  one  questions the  technical
ability to attain the goal of the 1984
HSWA--to reduce dependence  on  land
disposal.   Wastes  containing  organic
compounds will  be  treated,  resulting
in near-complete destruction of the
hazardous constituents.   Inorganic
wastes can  be  solidified to  produce
environmentally   safe treatment
residues.     Current   technical
difficulties in applying treatment
technologies  are   most   often
encountered   for  those   wastes
containing  mixtures of  organics and
inorganics.

    New  technology development is an
ongoing  process.   Some  new  or
innovative applications have arisen in
response to needs of the  Superfund
program,  others more directly related
to  needs   of   industrial   waste
management.  A  recent  study  by the
Congressional  Office of Technology
Assessment  identifies  several
promising,  but  not yet   commercially
available,  technologies.(1)  A recent
review   by  The   Hazardous  Waste
C.£H s.iiH5.IIl identifies  several
innovative  technologies.(3)    As
illustrated   in  Table  2,  some of these
have advanced  beyond the laboratory
stage and are  considered  ready for
pilot or commercial development.

Barriers  to  Compliance

     A    major   difficulty   in
implementing the Congressional mandate
to restrict  land disposal of wastes is
the lack of commercial  capacity for
                                    30

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TABLE 2.  EXAMPLES OF NEW TECHNOLOGICAL DEVELOPMENTS
Enzyme Destruction
UV Photolysis
Pyroplasma Processes
Plasmadust Process
Plama Arc
Circulating Bed
Incineration
High-temperature Fluid
Wall Reactor
Biological destruction of organics; does
not  involve  living  organisms;   can  be
maintained in immobolized systems  or applied
directly to wastes or contaminated material.

Used to detoxify  liquids  containing dioxin,
being  developed   for  application  on
contaminated  solids;  dioxin  mobilized  by
surfactants and subjected to  UV  photolysis;
can reduce concentrations by 90 to 99%.

Break-down  of waste  fluids  to  elemental
constituents; being  developed as  a mobile
unit; tested  for  destruction  of  chlorinated
organics;   low power consumption  and  rapid
start-stop mode.

Recovery of metals  from  iron  and steel  mill
baghouse  dust;  reduces  metal  oxide  to
elemental   forms;  iron removed with molten
slag; zinc  and  lead removed  as  gas;  tests
resulted in yields of 96% for iron, zinc, and
lead.

Destruction  of  PCBs  and PCB-contaminated
equipment; destruction and removal efficiency
of 99.9999%;  possibility  for  metal recovery
from molten slag

High  heat-transfer and  turbulence  allow
operation   at  temperatures   lower than
traditional incinerators; accommodates solid
and  liquid  wastes;  complete destruction  of
organics at  relatively low  temperatures;  no
need for  scrubber  system  to  remove  acid
gases;  particularly  cost-efficient  for
homogeneous wastes from oil  and petrochemical
processes.

Most suitable for  contaminated soil;  liquid
wastes require a  carrier; pyrolyze organics
to  carbon,  carbon  monoxide  and   hydrogen;
equipment   not  attacked  by   inorganic
components; mobile  units possible; reaches
destruction efficiencies  of 99.9999%.
                                31

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Penberthy Pyro-
Converter  .
Pyrolyzing Rotary
Rollins Rotary Reactor
Supercritical Water
Oxidation
Wet Oxidation
Vertical-tube Reactor
Glass-melting furnace technology adapted  for
destruction  of  organics;  suitable  for
liquids,  vapors,  solids  and sludges;  solid
residues  (inorganics) incorporated into glass
matrix; current use for production of HC1 and
destruction   of   chlorinated   organics,
therefore RCRA regulations not applicable.

Operates  in oxygen-free environment and at
lower  temperatures  than  conventional  kiln;
produces  gas suitable for energy recovery or
further   treated  to  recover   condensed
hydrocarbons;  recovery  of  metals  possible
without volatilization; reduced need for  air
pollution control; need to verify destruction
efficiencies of hazardous constituents.

Suitable  for viscous and  high-solids content
wastes;  no  need  for  supplemental   fuel;
reduced   gas  scrubbing   requirements;
high-transfer  efficiencies  may  increase
destruction   efficiencies   at   lower
temperatures.

Oxidize  organics  to  carbon  dioxide  and
water; high pressure steam or electricity
produced;  inorganic  salts  precipitated;
especially efficient with highly concentrated
organic wastes;  for water  containing   10%
organics, destruction efficiency greater than
99.99%; suitable for chlorinated solvents and
PCBs.

Suitable  for dilute aqueous waste that  cannot
be  incinerated or  biologically  treated;
destruction efficiencies  expected in range of
99%  to  99.99%;   oxidizes  organics  and
inorganics; not appropriate for halogenated
aromatics.

Adaptation of wet exidation into 1-mile deep
well system; operates at  lower  pressure than
conventional process;  currently applied  to
municipal wastewater.
Source:  The Hazardous Waste Consultant, "A Guide to Innovative
         Hazardous Waste Treatment Processes, "January/February, 1985,
         pp. 4-1  through 4-32.
                                32

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          TABLE 3.  DISTRIBUTION OF COMMERCIAL FACILITIES
          STATE
TREATMENT    INCINERATION*
Alabama
Arkansas
California
Connecticut
Florida
Georgia
Illinois
Idaho
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maryland
Massachusetts
Michigan
New Jersey
New York
North Carolina
Ohio
Oklahoma
Oregon
Pennsylvania
South Carolina
Tennessee
Texas
Utah
Virginia
Washington
1
1
7
5
0
1
6
1
3
1
0
1
4
1
1
9
6
6
0
11
2
1
8
3
2
6
1
0
3
1
1
1
1
1
0
2
0
0
0
1
2
1
1
2
0
2
3
3
3
0
0
0
1
0
1
0
2
0
* Many of these facilities have restrictions on concentrations and BTU
value; includes cement kilns.
Source:   The Hazardous Waste Consultant, "The Outlook for Commercial
          Hazardous Waste Management Facilities:   A Nationwide
          Perspective," March/April, 1985, pp. 4-1 through 4-49.
                                33

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treatment  and  incineration. The EPA
1981 survey emphasized that commercial
capacity accounted for only 1  percent
of  the  nationa^ total  for  these
alternatives.  As illustrated in Table
3, the number of  available commercial
facilities  is  limited  and  not
uniformly distributed  throughout  the
country.    While   total  unused
commercial  capacity  was estimated by
EPA to be less  than  1  percent of the
national  total,  the  cumulative
capacity  utilization  of current
facilities  is estimated to be only 35
percent.

     Although it is quite obvious that
there is a diverse range of current
and new alternatives to land disposal
of  wastes,  several  uncertainties
inhibit  new capacity development:
siting problems,  market availability,
regulatory  requirements,  expeditious
permitting.

Siting

     The  ability  to  site  a  new
facility  is  perhaps   the   major
impediment.  The prevalent attitude by
potential host communities is that any
waste service facility is  undesirable.
Unfortunately the public has not been
willing to acknowledge  both the need
for alternatives  to land disposal  and
differences    in    health  and
environmental risks associated  with an
incinerator  or  treatment  facility as
compared to land  disposal  facilities.
In the last two years, there have been
nearly  15  major attempts  at  new
facility development throughout the
country.(4)     None  have  been
successful.

Market Availability

     Future  markets  obviously impact
commercial  development.  Three factors
contribute  to  uncertainties  about
potential  hazardous  waste markets.
The first is the  continual attempt by
states and communities to restrict the
free transport  of hazardous  waste
across  state  and  county borders.   In
planning a new commercial facility,
there must be some certainty about the
volume  of waste  that  can  be expected
at  the  facility   over   time.
Restrictions  on  movement of  waste
across  regions, often  is accomplished
through  imposition of high tax rates
on out-of-state wastes.

    Second,  many states  further
inhibit  commercial  development  by
imposing differential tax rates for
wastes  managed  at  commercial  and
generator-owned  facilities.
Imposition  of high  taxes  only  at
commerial  treatment  facilities plus
the  cost   of   installing  new
technologies  places these facilities
at a competitive  disadvantage  with
land disposal.   Also, the greatest
potential   for  "new"  technology
development  on  a large-scale rests
with the commercial  industry.   High-
cap i to!  investment  is  needed.
Generator   development  may  be
discouraged  because of limited rates
of return  on such investment.   By
imposing a high tax on only commercial
facilities,  a ,further competitive
disadvantage   results  between
commercial  and  generator-owned
facilities  thus,  impeding   future
commercial developments.

    Finally, the 1984 HSWA mandate
minimization  of wastes by  generators,
resulting in some uncertainty as to
the size  of future markets as  well  as
the composition  of  these  wastes.
Although  minimization is desirable, it
does  have  a direct  impact  on
commercial  development of innovative
technologies.  Until manufacturing
processes have been identified  and the
volume   and  the  composition  of
hazardous  waste  have  been estimated,
analysis of future market potential
will be highly  speculative.  New
investments  are  not  likely  until
future  trends  can  be  identified with
some certainty.
                                   34

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Regulatory Impact

     Another uncertainty of particular
importance  to  the  development  of
innovative  alternatives  to  land
disposal  lies  with   potential
regulatory requirements.  Currently
there are no  standards for treatment
processes other than incineration.  As
EPA  begins   the  evaluation   for
restricting wastes  in  land  disposal,
health-based  thresholds  will  be
developed.  These  thresholds  will  be
used as standards by  which to judge
the effectiveness and efficiency of
alternative  treatments,   those
currently available  as well  as
innovative developments.

     If new technologies  are going to
be developed,  the capital  investment
for scale-up and  construction will be
very high.   Thus, uncertainty about
the acceptance of such technologies
within  the  regulatory  arena can delay
necessary commitments  to  these
investments.

     Additional  uncertainties about
potential technical adjustments needed
to  meet regulatory  requirements
discourages  acceptance  of   the
innovative  alternatives.   The  Agency
must  begin  to  evaluate  new
technologies,   indicating  criteria for
acceptance   in  the   Resource
Conservation  and  Recovery Act  (RCRA)
and Superfund programs.  Executives of
treatment companies recently reported
to Congress that delays by the Agency
in evaluating new technology are major
factors in failures  to  implement them
on a commercial scale.(2)

Permitting Process

     Finally,  a  major  impediment to
development rests with the slow pace
and  established  priorities  of  tne
permitting process.    Before  any
treatment facility owner  or operator,
whether employing traditional  or  new
technology,  can engage in hazardous
waste  service  activities,  it  is
necessary to  obtain a permit granted
under the RCRA program.   The  record
to-date  for  permitting  is  very
poor.(8)   Of the facilities  classified
by   EPA   as   storage/treatment
facilities,  only 353 of an expected
2327  facilities have received permits.
The majority of these  are for storage
of hazardous waste rather than  for
actual treatment.   Only 18 of the  219
potential incineration facilities have
received permits; few of  these  are
commercially owned.

     Compounding the  situation  is  the
permitting schedules  mandated  by  the
1984  Amendments.   These  schedules
require that EPA first give  attention
to  permits  for  land   disposal
facilities,  next   incineration
facilities,   and  finally,  to give
attention  to  existing  treatment
facilities.   The  new  National Permits
Strategy attempts  to redress this
problem  by placing higher  priorities
on   commercial  treatment   and
incineration capacity development.(7)
EPA  has recognized  the  need   to
expedite  permits   for  existing
commercial incinerators, for expansion
of   treatment   and   incineration
capacity, as well as  for  research  and
demonstration projects.  However,  the
permitting process for the  latter will
be dependent somewhat on  concomittent
development of regulatory standards
for new  technologies.

Conclusion

     If the industrial sector of our
nation  is   to  implement   the
congressional  mandate  for  reduced
dependence on land disposal, a greater
commitment  is  needed  for   rapid
development  of  new  treatment  and
incineration  facilities.    The
commercial  waste  service  industry is
eager  to invest in expansion  of
                                   35

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current  capacities and development  of
new innovative  technologies.   Federal
and state officials,  the  public,  and
industry must be dedicated to reducing
the   barriers- to  commercial
development.

     Siting problems must  be resolved;
regulatory  standards  identified,  and
permits  processed expeditiously.   We
do not  have  the luxury  of waiting
several  years  to develop  appropriate
institutional mechanisms  to address
these   problems.    If  we  are   to
implement treatment alternatives  to
the fullest extent possible,   it  is
necessay for  the government  agencies
to commit  sufficient resources for
resolving  these   implementation
barriers.

     The country cannot  affort  to
continue the  current slow  pace  in
attending  to   waste  management
problems.  The legislative clock  is
ticking; like it or not,  all wastes
may be  restricted from land  disposal
in 5  years.  That leaves very little
time  to expand  current  commercial
capacities and  to  invest  in  newer
treatment alternatives.

References

1. Congressional   Office of Technology
    Assessment,  .$Mj}e_lf__u n.cl.
     Strategy,  "Chapter 6.   Cleanup
     Technologies",  OTA-ITE-252,
     (Government  Printing Office:
     Washington,  D.C.,  1985),    pp.
     171-220.
  .    .
    ^'Environmental  Laws,  Policies
     Impede Use of  Waste Treatment
     Technologies,  Panel Told," Vol.
     16(2):  pp.  44-45, 1985

3. The Hazardous Waste Consultant,  "A
     Guide to  Innovative Hazardous
     Waste  Treatment  Processes,"
     January/February, 1985,  pp. 4-1
     through 4-32.
4. .Ibid_j_  "The  Outlook  for  Commercial
     Hazardous   Waste  Management
     Facilities:    A  Nationwide
     Perspective,"  March/April,  1985,
     pp. 4-1 through 4-49.

5. Mackie,   J.A.   and  K.   Niesen,
     "Hazardous Waste Management:   The
     Alternatives,"  Ch e m j.c_a.l
     Engineering,  Vol.  19ll6j:  50-64,
     1984.

6. Porter-Cathcart,     N.,
     "Solidification  Testing
     Protocols,"  presented at  the  6th
     National  Conference  on  Waste
     Management in  Canada,  Vancouver,
     B.C. November 7-9, 1984.

7. U.S.  Environmental  Protection
     Agency, Permits and State Program
     Division, "Draft Revised  National
     Permits    Stategy   for
     Implementation of the Resource
     Conservation an Recovery Act,"
     April 1985.

8. Weddle,  B.  "Summary Report on  RCRA
     Activities-March,  1985,"  U.S.
     Environmental  Protection Agency,
     Office of Solid Wastes,   Permits
     and State Program  Division, April
     25, 1985.

9. Westat,  Inc.,  National  Survey of
     Hazardous Waste Generators and
     Treatment, Storage,  and  Disposal
     Facilities Regulated under  RCRA
     in  1981,  prepared  for  U.S.
     Environmental  Protection Agency,
     Office  of  Solid  Wastes  and
     Emergency Response, April 1984.
                Disclaimer

   The work described in this paper was
   not funded by the U.S. Environmental
   Protection Agency.  The contents do
   not necessarily reflect the views of
   the Agency and no official endorse-
   ment should be inferred.
                                   36

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          LABORATORY SCALE TEST SIMULATING CODISPOSAL LANDFILLS

                             Artur Mennerich
                  Technical University of Braunschweig
                            3300 Braunschweig
                                W.-Germany

                                ABSTRACT
     In West-Germany in most cases special facilities are used for the
handling of industrial wastes. Because of the extensive measures to avoid
environmental pollution, this kind of waste treatment is very costly. Con-
sequently, from the economical point of view, codisposal would be advan-
tageous. Before a certain waste is codisposed, negative effects on the
landfill behaviour must be excluded. Because of the complex reactions
taking place within sanitary landfills, the prediction in the individual
case as to whether or not these conditions can be fulfilled, is very
difficult.
     For this purpose at the Technical University of Braunschweig, a
laboratory scale container test has been developed simulating the condi-
tions within a landfill. With the container 'test, codisposal of the
following industrial wastes has been investigated: electroplating sludge,
cyanide wastes, mercury sludge, acid sludge,, chlorinated hydrocarbons,
plant protective agents.
INTRODUCTION

     According to the German law on
waste disposal the handling of
special wastes requires special
measures to avoid environmental
pollution. This means that, in
present practice these wastes have
to be treated in special waste
incineration plants or disposed of
in special waste landfills. Oper-
ating of these facilities is very
costly because of the extensive
technical installations necessary
to prevent environmental hazards.
Furthermore, in West-Germany it is
very difficult to find new indu-
strial waste landfill sites. Hence
prolonging the running time of the
existing plants is an important pro-
position .

   One possibility to achieve this
is codisposal. Surely there are a lot
of special wastes that may be codis-
posed. Of particular interest are
industrial wastes arising in large
amounts but containing only low
concentrations of hazardous sub-
stances. The main criteria to be
fulfilled before codisposal is
carried out are:

- To render the long-term integration
  of the landfill into the biocycle,
  the biochemical degradation pro-
                                     37

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  cesses within the landfill must not
  be affected.

- Toxic substances not removable
  during leachate treatment or dis-
  turbing the leachate treatment
  process itself must be prevented
  from getting into the leachate.

- The buildup of volatile hazardous
  substances reaching the atmosphere
  with the landfill gas must be
  avoided.

If a substance having adverse effects
on the landfill is codisposed, the
subsequent sanitation will be - if
at all possible - very costly. This
means, before codisposal is done, an
exact prediction of the consequences
is recommended. This is very diffi-
cult, however, on account of the
complex physical, chemical and bio-
chemical processes taking place
within a landfill. These uncertain-
ties are the main reason that
codisposal in West Germany is quite
unusual at present time.

One possible method to predict the
behaviour of special wastes after
their disposal are leaching tests.
With regard to codisposal, there are
some serious drawbacks, because
neither reciprocations between bio-
logical degradation processes and
constituents of the special waste nor
the adsorption capacity of the
municipal solid waste (MSW) are con-
sidered. Therefore, one can say that
leaching tests in most cases are not
sufficient to decide for codisposal.

PURPOSE

   At the Technical University of
Braunschweig,a research project
sponsored by the Federal Ministry of
Research and Technology (BMFT) has
been performed to develop a test
procedure simulating codisposal
landfills. On one hand, this test
procedure should be well reprodu-
cible and require only little time
and money. On the other hand, it
should simulate a landfill inclu-
ding movement of water and gas as
well as the sorption capacity of
the MSW. In particular, within the
test, the steps of the decomposi-
tion of the refuse including ini-
tial aerobic processes, the acidic
phase and the methanogenic phase
should be run through gradually.

APPROACH

After several preliminary trials, a
commercial 120 1 polyethylene refuse
container was chosen as the base
of the test setup. For the test, it
is provided with a gas tight PVC
cover and installations for gas
withdrawal and water exchange.
Furthermore, an equipment for
leachate recirculation is installed
consisting of a leachate collecting
tank with a submerged pump and a
leachate distributor on top of the
test container. Fig. 1 shows the
test equipment. It is a closed
system providing the possibility to
capture all flow of gaseous,liquid
and solid matter. One test series
usually comprises several containers
standing in a room constantly heated
to 30 C to get good conditions for
the anaerobic processes. To start a
test, the containers are filled with
a mixture of 2 parts crude MSW and
1 part composted MSW, both shredded
to a particle size of less than 5cm
and brought to a water content of
65 %. The total weight of the refuse
within a container may vary between
60 and 90 kg. One container recei-
ves no additional substances serving
as a control, while the other ones
receive various amounts of the con-
cerned special waste added as a
                                     38

-------
      PVC - cover
    8

    7

    6

    5

 30000


 20000


 10000
                                              pH  [-]
                                              COO, BODS [mg/l
                                                                coo
                                                                BODS
                                              gas composition[Vol-% ] cumulated gas[ I ]
                                                                           iOOO
                                                                  150     200
                                                                  time  [ d
Figure 1. Schematic view of the
          test container

layer within the upper third of  the
MSW, After filling, the containers
are sealed. During the test period,
leachate is pumped back 8 times  a
day to the top of the container.
Once a week, 3.5 1 of leachate are
withdrawn for analysis and replaced
with an equal amount of tap water,
simulating precipitation and leach-
ate generation. In addition, once a
week a sample of the produced bio-
gas, which is quantitatively
collected over the whole test, is
taken and analyzed by gas chromato-
graphy.

 - Pig. 2 contains the pattern of
some leachate and gas data typi-
cally observed during a container
test.
Figure 2. Typical pattern of
          leachate and gas  data
          during a container test

The acidic phase lasts about 40 days
indicated by rising organic pollu-
tion (COD, BODg) and falling pH of
the leachate due to hydrolysis  and
acidification of organic constitu-
ents of the refuse. During  this
time very little gas is produced.
The gradual rising of methane  (CH.)
content indicates the beginning  of
methane buildup from the organic
fraction of the leachate. During the
period of maximum gas production
(i.e. maximum methanogenic  activity)
gas is characterized by a CH. con-
tent of about 50 %. The volatile
fatty acids  (VFA) are converted into
CH. and CO,, causing a sharp drop of
the organic
                                    39

-------
pollution and a rising pH of the
leachate. After 80-100 days, the
end of intensive anaerobic degra-
dation is indicated by diminishing
gas production -and methane content
rising to 60 - 70 % in the produced
gas. Note, that at this time
leachate concentrations have sunk
below 500 mg/1 BODg and 3000 mg/1
COD. In a landfill, this period
might be called "stabilized methan-
ogenic phase".

   In general, a test is terminated
if:

- the leachate concentrations have
  reached concentrations below
  50 mg/1 BOD5 and 500 mg/1 COD,

— the gas production has dropped
  below 1-2 I/day.

This being the case, one may say
that anaerobic decomposition of the
refuse is nearly completed and a
stable state is reached. In general,
this takes about 150 - 200 days
provided no toxic effects of the
added special waste delay the decom-
position process.

RESULTS

Testseries with electroplating
sludge

   The first special waste inves-
tigated in the container test was an
electroplating sludge with conside-
rable amounts of copper, chromium
and nickel. Table 1 shows the
contents of the various test con-
tainers.  The MSW was brought to a
water content of 65%, as mentioned
above. Water content of the electro-
plating sludge was 23%.
Container  MSW
No.
Electroplating
    sludge
                   kg
       % of MSW
1
2
3
4
5
80
79.2
76.0
72.0
63.8
0
0.8
4.0
8.0
21.25
0
1.0
5.3
11.1
33.3
Table 1. Contents of the electro-
         plating sludge test series

The higher the portion of electropla-
ting sludge, the smaller the amount
of MSW (i.e. of organic substances)
present in a container. Therefore,
the initial production of VFA was
lower with high portions of the
industrial waste. Moreover, the
addition of electroplating sludge
led to a better buffer capacity of
the leachate. These facts had advan-
tegous effects on the anaerobic
decomposition processes, as can be
seen in Pig. 3.
Compared to the control, the con-
tainers with electroplating sludge
showed the tendency to produce lower
concentrated leachate with a higher
pH. As a result, the methane produc-
tion began first within the containers
which had the highest amounts of
electroplating sludge. That is, the
industrial waste addition had no
adverse effects on the anaerobic
degradation processes within the
refuse. Note, this was the case even
at an addition ratio as high as 33%.
In practice, the amount applied to
container 2 would be more realistic.
So one can say, codisposal of this
sludge would enhance, but by no means
inhibit the anaerobic processes within
a landfill.
                                    40

-------
     gas yield [I/kg VS 1
                                          Cu  [mg/l
     pH[-l
30000


20000


 10000


    0
20000

15000

10000

 5000

    0
     COD[rng/l]
BODS [mg/l]
        electroplating sludge
        addition
  0 %

  1,0%
                         5,3%

                         11,1%

                         33", 3%
            50
               100
150     200
 time [d]
  Figure 3. Leachate and gas data of
            the  test series with
            electroplating sludge

     More  interesting than this,
  however, are the effects of codis-
  posal on the leachate quality. In
  Fig. 4,  average  metal contents of
  the leachates  produced are presented
  as a function  of the addition of
  electroplating sludge. There are
  two curves  for each metal, one for
  the initial acidic phase and another
  for the  methanogenic phase. As can
  be seen, differences between these
  two phases  are considerable. Nickel
                                             0,1
                                            0,01
                                           0,005
                                                                acidic phase
                                                               me thanagenic phase
                                                Cr [mg/lI
                0,1



               0,01

                100

                 10

                  1
                                       0,1
                                      0,05
                                                               acidic phase
                                                          tBefhanogenic phase
                                           Ni  [mg/l]
                                                          acidic phase
                                                               enic phase
                 '  0     10    20     30     40     50
                          electroplating sludge addition [%]
                                     Figure  4.  Leachate metal  contents vs.
                                                ratio of electroplating
                                                sludge added

                                     concentrations dropped by 2 orders
                                     of magnitude, once a neutral pH-
                                     value of the leachate was esta-
                                     blished. As to the elements Cu and
                                     Cr,  the influence of rising pH-values
                                     at the  beginning of the methane pro-
                                     duction also was observable. As -a
                                     whole,  data presented in  Fig. 4
                                     clearly show that in a landfill
                                     during  the acidic phase,  a leachate
                                     containing high metal contents will
                                     arise,  even if codisposal is not
                                     carried out. On the other hand,
                                     influence of electroplating sludge
                                     codisposed is very strong during the
                                      41

-------
acidic phase. This is true above  all
for nickel. Therefore, codisposal
should not be carried out during  the
acidic phase.
In addition, Fig. 4 shows the  influ-
ence of the amount of industrial
sludge codisposed. For copper  and
nickel, this influence was greater
during the acidic phase than during
the methanogenic phase. However,
electroplating sludge addition also
affected leachate concentrations  in
the raethanogenic phase. Ni-concen-
trations rose from 0.1(control) to
0.3 and 0.7 mg/1 at 1% and 5.3%
electroplating sludge addition, res-
pectively. At higher ratios, Ni-
content remained stable. In opposi-
tion to this, Cu- and Cr-concentra-
tions gradually rose over the  whole
extent of addition ratios. However,
leachate loadings didn't rise  pro-
portionally with the amount of the
industrial sludge.
In general, the load of metals washed
out per 1 kg total solids of the
electroplating sludge decreased as
the addition ratio was raised.
Table 2 shows this tendency.
Container
No. Cu
2 2.23
3 0.805
4 0.251
5 0.283
Cr
0.776
0.740
0.081
0.068
Ni
14.5
6.95
2.19
1.25
microorganisms present in the  re-
fuse. Although an increasing metal
loading of the leachate was observed,
the MSW was shown to have the  capaci-
ty to retain a large part of the Ni,
Cu and Cr during the methanogenic
phase. Therefore, in principle
codisposal of this special waste
could be a convenient and adequate
technique, provided that a proper
landfill operation is guaranteed.

Results of tests with additional
special wastes

   Two additional test series  were
arranged to investigate the
behaviour of various special wastes
and some pure substances as codis-
posed. In this case, it not only
was the question of codisposal. We
also tried to find out in what way
matter getting from non point  sources
(household, allotments, etc.)  into
the refuse affects the landfill
behaviour.
Table 2: Leachate output of metals
         related to the amount of
         electroplating sludge within
         the containers (rag/kg)  during
         the methanogenic phase
As a result of this series it can be
concluded, that the addition of  the
electroplating sludge causes no
toxic effects on the anaerobic
   Gas
   AOO

   300

   200

   100
Yield [I/kg VS ]
1
1
•I
I
I
I
I
I
1
, — ,




n
r—.


r—i




\ 	 \
1 	 1






r~i
                                                \\\\°~\\\\\\
                                                 \V-A  *'
              *>  - %
                   C-
                        \\\\
Figure 5.  Gas yields of containers
          with different special
          wastes
                                    42

-------
In Fig. 5, gas yields per kg volatile
solids (VS) of the MSW within the
containers are presented serving as
a first indication of the influence
on the anaerobic processes within
the refuse. Tab. 3 contains data of
the special wastes added and the
appearance of hazardous substances
in the leachates.
The wastes containing hydrocarbons
acted quite differently within the
refuse. The anaerobic degradation
processes were not markedly influ-
enced by the coke plant residue.
Gas yield of the tar container
however, was very low, although
the methane content was as high
as 50 %. This indicates
container no.
special waste
4
coke plant
residue
5
tar
6
Berlin blue
sludge
7
mercury sludge
8
chlorinated
hydrocarbons
9
plant protective
agents
10
hardening salt
11
acid sludge
amount of
special w.
(%) Of MSK
8.2
8.2
8.2
8.2
1.3
1.1
3.6
3.6
main specific
substances
benzene
xylene
naphthaline
pyridine
benzene
xylene
naphthaline
pyridine
cyanides
mercury
d ichlorome thane
trichloroethane
trichloroethene
tetrachloroethene
Atrazine
Oxydeme ton -me thy 1
Methaben zoth iaauron
barium
cyanides
sulfates
sulfites
maximum leachate
concentration
(in parenthesis: control)
(mg/1) (mg/l»
3.10 (0.114)
0.539 (0.580)
0.561 (0.431)
2.80 (0.210)
0.349 (0.114)
0.500 (0.580)
2.20 (0.431)
38.0 (0.210)
9.4 (<0.01)
0.78 (0.006)
329.0 (0.020)
22.0 (0.012)
19.0 (0.013)
6.6 (0.012)
15.60 (<0.01)
4.80 (<0.01)
4.24 (<0.01)
2.8 ( 1.7 )
1130 «0.01)
2150 ( 225)
815 ( 88)
Table 3. Leachate concentrations of the test series with various
         special wastes
                                    43

-------
an inhibition of the anaerobic degra-
dation not in the methanogenic phase,
but already occurring during waste
acidification. Pyridine is supposed
to be the reason for this, because
its concentrations were extremely
high in the leachate of the tar con-
tainer  (Tab. 3).

   Two wastes containing cyanides
were investigated:

A sludge arising from the "Berlin-
blue" production and a hardening
salt. Within the "Berlin-blue"
sludge, however, the cyanide content
(25 g/kg) was almost completely
fixed in complexes. Therefore,
addition of this sludge didn't lead
to an inhibition of the anaerobic
processes within the MSW. This was
not the case with the hardening salt,
which in addition had a higher CN
content (163g/kg). It caused the pH
of the leachate to rise up to 10.0
and to remain stable at that level
during the first 170 days of the
test run. The biochemical degrada-
tion didn't start before the CN
content of the leachate had dropped
below 30 mg/1 and a neutral pH value
was established.

   The high content of mercury
(93 g/kg)  within the sludge added to
container 7 did not lead to any
delay of the decomposition pro-
cesses. This could be explained by
the fact that the buffer capacity
of the leachate was raised from 660
(controls)  to 1070 mg/1 as CaCO3
by the addition of the mercury
sludge, which in turn enhanced
methane production. The Hg concen-
tration was increased by 2 orders
of magnitude. However, the leachate
load during the test only repre-
sented 0.03 % of the mercury added
to the container. That is, MSW can
even retain Hg in large amounts. In
practice, this sludge with its high
Hg content should not be codisposed
On  the other hand this test
shows, that small amounts of Hg
present within a landfill will not
lead to any trouble.

    Of each volatile chlorinated
hydrocarbon (VCH), 125 ml were added
to  container 8. These amounts led to
a total inhibition of the anaerobic
processes. Evaluation of that test
run is difficult, because VCH
proved to migrate trough the poly-
ethylene walls of the container in
gaseous form. Moreover, leachate
concentrations changed by chance
over a wide range. As a result,
codisposal is surely not a method
suited for wastes containing VCH,
because they would move uncon-
trolled in gaseous and liquid form.
Furthermore, anaerobic processes
would seriously be affected.

    The plant protective agents
(PPA)  didn't affect the degradation
processes. In addition, only 0,2 %
of  the amount of PPA added were
found in the leachate. That is, the
PPA have been anaerobically degraded
to  a great deal.

    The acid sludge added to con-
tainer 11 had a low pH and contained
large amounts of sulfates and sulfi-
tes. All this is suspected to inhi-
bit methane producing bacteria. PH
of  the leachate remained at about
5 from the beginning and no biolo-
gical activity could be observed.
Even an artificial raising of the
pH  achieved by lime addition to the
refuse surface after 250 and 275
days was not able to encourage
methane production.  This indicates
the high sulfur content present in
the container is the main reason
for the inhibition of anaerobic
degradation processes.
                                     44

-------
CONCLUSION
   Results of the test series show
that the container test makes it
possible to run through the processes
taking place within landfills in a
fairly short time. Therefore, the
container test is a suitable method
to predict the effects of codisposal
on landfill behaviour.
 added chlorinated hydrocarbons and
 the acid sludge. These results give
 some indications of the problems
 that might be caused by the tested
 substances getting into domestic
 refuse. To obtain more detailed
 and reliable data, however, at
 least 3 containers with various
 amounts of one special waste should
 be used for the test.
   The addition of various amounts
of an electroplating sludge con-
taining Cu, Ni and Cr caused no
adverse effects on the anaerobic
processes within the refuse. Metal
contents in the leachate were
raised, but overall only small
portions of the metals present in
the containers appeared in the
leachate. The results of this test
series show that, once a land-
fill has reached the. methane phase,
codisposal of the electroplating
sludge would cause only slightly
increased metal concentrations in
the leachate. Hence, codisposal
might be applied in this case pro-
vided that a tight base liner and
a well functioning leachate drai-
nage exist.

   In additional test runs,
various industrial wastes and
hazardous substances proved to act
very differently. No effects on gas
production were observed after
addition of; a mercury sludge, plant
protective agents, Berlin Blue
sludge containing cyanides or a
coke plant residue. Anaerobic acti-
vity was markedly impaired both by
the addition of the hardening salt
and by the tar; almost no gas pro-
duction could be observed with the
 REFERENCES
 1. Cheyney, A.C., Experience with
    the codisposal of hazardous waste
    with domestic refuse, Chemistry
    and Industry, 3. Sept. 1984,
    609-615


 2. Mennerich, A., Untersuchungen
    fiber das Verhalten von produk-
    tionsspezifischen Abfallen mit
   •toxischen Inhaltsstoffen bei
    der Ablagerung mit Hausmiill
    Report, unpublished, July 1984


 3. Mennerich, A., Stegmann, R.,
    Entwicklung eines Testverfahrens
    zur gemeinsamen Ablagerung von
    kommunalen und industriellen
    Abfallen  Report, unpublished,
    May 1983
 4. Stegmann, R., Criteria for the
    codisposal of municipal and
    industrial solid wastes, Proc.
    ISWA Symposium, Munich, 1981,
    751-771
              Disclaimer

The work described in this paper was
not funded by the U.S. Environmental
Protection Agency.  The contents do
not necessarily reflect the views of
the Agency and no official endorse-
ment should be inferred.
                                    45

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        RAPID APPRAISAL OF RELATIVE RISK BY SOIL APPLIED CHEMICALS
                      FOR GROUNDWATER CONTAMINATION

                  Tammo S. Steenhuis and Lewis M. Naylor
                            Cornell University
                            Ithaca, NY  11853
                                 ABSTRACT

    A  simple  mathematical screening model  is  presented that  can  aid in
evaluating  the  relative  risk  to  groundwater  from  applying  non-polar
synthetic  organic chemicals  to  soil.    The  basic premise  is  that  the
magnitude  of  the quotient of  the chemical concentration  in  the ground-
water  and  the maximum allowable concentration  (as  established  by  EPA or
Health Departments) represents the health risk of a chemical.   The closed
form  screening model is  based on  conservative,  simplifying  assumptions
and requires only readily available  data  such  as:   basic soil properties
(organic matter  and  saturated hydraulic  conductivity),  organic chemical
properties (octanol-water partition coefficient and degradation rate) and
environmental factors (recharge rate and depth to groundwater).

     The methodology  was  applied  to assess the  relative risk of organic
chemicals  in   municipal   sewage   sludge   and  pesticides   applied   to
agricultural land.  The results were realistic.
Introduction

     Application of organic wastes
to land  can provide  benefits for
both  the  generator and  the  user,
but  questions  have  been  raised
regarding the potential for pollu-
tion of  groundwater  from constit-
uents  of  the  waste  as  a  conse-
quence  of  this  practice.    Syn-
thetic organics are one  class  of
constituents   that   may  be   of
concern.        Municipal    sewage
sludges,  one   group   of  organic
wastes applied  to land,  are  known
to   contain  synthetic   organics
(19).  The presence of these chem-
icals  in  groundwater  represents a
health  risk to  consumers.    How-
ever, evaluation  of  that risk has
been  difficult  to  assess.    This
paper  will  consider  the  relative
risk  to  groundwater  of  synthetic
organics  from   municipal   sewage
sludge, commonly applied to land.

     The   fact   of   groundwater
contamination by  synthetic  organ-
ics  from municipal   and  agricul-
tural   sources    has   been   well
documented (11,13).  While a great
deal  may  be  learned  about  the
movement  of   synthetic   organics
through  soil  from  the  detailed
study  of  such examples,  research-
ing  the  movement  of  each  of  the
millions of  synthetic organics in
the  thousands of  soil types would
be   prohibitively  expensive  and
enormously  time   consuming.    One
                                   46

-------
approach to  the solution  of  this
problem  is  to   develop  simple,
though  fundamental  relationships
which   describe   the   important
soil-synthetic  organics  interac-
tions as they  relate  to transport
mechanisms.     For  many  of   the
synthetic  organics  identified  in
sludge   in   important  concentra-
tions, data on the necessary chem-
ical properties are available.

Purpose

     The purpose of this paper is
to  describe  a model  that  can aid
evaluation of the relative risk of
movement of  synthetic organics to
groundwater.    The  screening model
will  be used   to  identify  those
chemicals  in  a  particular  waste
that  pose  the  greatest potential
for  exceeding  maximum  tolerable
concentrations   in   groundwater.
While identification  of the abso-
lute  risk  of  a  specific chemical
for  all soils and  environmental
conditions will  not  be attempted
in  this  paper,  assessing relative
risk  of  chemicals using  a single
set  of  very conservative  assump-
tions for soil and  water interac-
tions  is  straightforward.     In
addition, such assumptions provide
a "worst case"  example  so that in
other settings public health risks
from   groundwater   contamination
will likely be much lower.

     Modelling   in   detail   the
leaching of  chemicals  applied  to
soil may be  based on  a three-step
approach.  The first  step identi-
fies, based on a readily available
data,  chemicals whose  concentra-
tions  in  groundwater  will  pose
the  greatest  health  risk.    The
second step models the actual time
series  of  the  chemical concentra-
tion in water during the year.  It
requires   a    more   sophisticated
model   and   also   requires   more
detailed  input  data.   The  third
step   determines   the   remedial
action.  For example, (for recycl-
ing sludge to the land) the timing
and  application  rate  is  designed
suoh  that  the  concentration  of
chemicals of  the  greatest  poten-
tial   risk    remains   below   the
standard.

     This  paper  deals  with  the
methodology  for  the  first  step.
Models, like  Behavior  Assessment
Model for Trace  Organics  in Soils
(6)  or   Model  for   Underground
Solute Evaluation (15) may be used
for steps 2 and 3.

Modelling Philosophy

     A  rapid  appraisal of  poten-
tial risk of many chemicals over a
broad range of  environmental con-
ditions must  necessarily  be based
on readily available  data.   These
data describe basic  chemical  and
physical  properties  of  soil  and
synthetic organics  and  are  appro-
priate  for  rapid  screening  tech-
niques.    The  assessment  metho-
dology  therefore  is  developed  in
such  a  way   that  only  generally
available  data  are  required  for
input.   The  following simplifying
assumptions are made:

   Soil  consists  of  a root  zone
   (with  organic  matter)  and  a
   subsoil.       Each   layer   is
   homogeneous.
•  Steady-state movement  has been
   established as a consequence of
   regular land applications.
   Chemical has  a  linear  adsorp-
   tion  isotherm  and  has a  first
   order degradation rate.

     In order not to underestimate
the hazard,  a worst case situation
is simulated.  Therefore,  the fol-
lowing   additional   conservative
                                   47

-------
assumptions are made.

•  No  plant  uptake of  the  chem-
   ical occurs.
*  No volatilization of  low molec-
   ular   weight   chemicals   takes
   place  since   the   chemical   is
   considered to  be incorporated.
•  No significant adsorption below
   the root zone  occurs  because of
   the lack of organic matter.
«  Groundwater  directly below  the
   application  site  is  withdrawn
   for drinking purposes.

     Thus,  all   of the  chemical
applied  to  the  soil   and/or  its
degradation  products  are   consid-
ered  to be  potentially leaehable
to  groundwater that   may  be  used
directly as drinking water.

The Model

     The basic premise is  that  the
relative health risk of  a  chemical
that  enters  the  groundwater   is
represented by the  relative  magni-
tude  of  the  ratio  of  the  concen-
tration  of  the  chemical   in  the
groundwater to  the  allowable  con-
centration  of  non-carcinogens  as
established  by the U.S.  Environ-
mental   Protection   Agency   (EPA)
(14,20).   For chemicals which  are
known  carcinogens,  the  most  con-
servative  concentration  is  used
which   represents  an   additional
cancer  risk  of   1  in  10,000,000.
This risk is  approximately equiva-
lent to that  of smoking  0.14 ciga-
rettes in a lifetime.

     For  the  development   of  the
model it  is  important to  note,  as
an example, that  the water flowing
into  a  well  consists  of a compos-
ite of  the water surrounding  the
well screen.  As  these screens  are
usually  several  feet   in   length,
the  groundwater  quality  entering
the  well  through  the  well  screen
will  not  reflect  any   localized
high    chemical    concentrations
occurring during  the  year.   As  an
example, under  dynamic  conditions
the  chemical is  assumed  to move
through the soil  as a  band  of high
chemical   concentration   in  the
groundwater  (Figure  1).   As this
band  of  high  chemical  concentra-
tion  water  moves  down  past the
well  screen,  water  entering the
well  contains  a  chemical  concen-
tration   representative   of  the
average  of  that  for   all   water
entering the well.   Under  steady-
state  conditions  assumed  by this
model  a  uniform  chemical  concen-
tration would  move past the well
screen.  Therefore it  is  consider-
ed  that  groundwater chemical con-
centrations  averaged  over  a year
provide  an  acceptable  indication
of   probable   quality   in  this
initial screening model.
        well
                    water table
                 )  steady-state conditions
                     dynamic conditions  -
          ehemicBl concentration 	»-


 Figure 1. Chemical concentration 01 o function of depth In
       grounduioter relatiue to the well screen length,

     The   concentration   of   the
chemical  in the  groundwater  is a
function of  the amount of  chemical
applied,  the  amount  of  water  in
which it  is dissolved,  the  degra-
dation  rate,  and  the   time   the
chemical is  in the soil.   The  time
available for degradation  is equal
to the travel time of the  chemical
                                   48

-------
from  the  soil   surface   to  the
well.    For  non-polar  chemicals
which   are   adsorbed   mainly   to
organic  matter,   the  travel  time
can  be   expressed,  based  on  the
assumptions  made before,  as  for
the zone with organic matter as
tp =
     Z (k
             I)
          R
                          (1)
for the unsaturated zone below the
zone with organic matter as:
     (GWD - Z) 6
          _
                          (2)
The total travel through the unsat
urated zone  is  obtained by adding
both  travel  times in  equations 1
and 2, viz:
t =
    Z * p * kj- GWD * 8
             R
                          (3)
where:

t   is

tr  is
tu  is
P
k
is

is
is
GWD is
e   is
    is
travel time in vadose
zone,  days
travel time in zone with
organic matter, days
travel time in remaining
part of unsaturated zone,
days
depth of zone with
organic matter, m
density of soil, g/cm3
adsorption partition
coefficient, emVg
depth to groundwater, m
average moisture content
in subsoil above water
table, cm3/cm3
average rate of recharge,
m/day
                              tion partition coefficient and the
                              amount of recharge.   Each will be
                              discussed.

                                   The  moisture  content  in  the
                              unsaturated zone is  a function of
                              the yearly amount  of recharge  and
                              the  hydraulic  conductivity  (15)
                              and may be expressed as
                                                        R
                                              [ -1 in ( iL. ) + 1 ]
                                            13
                                       where:
Ks   is the saturated hydraulic
     conductivity in m/day.

     The  advantage  of  using  the
saturated  hydraulic  conductivity
(Ks)  rather   than  the  moisture
content  is  that Ks  is  a  function
of  the  soil properties.   Average
saturated conductivities are known
for a wide range of soils.

     The    adsorption    partition
coefficient may  be  found  from the
octanol/water   partition   coeffi-
cient  and the  amount   of  organic
matter in the soil as follows (2):
                                                (0.52 log,0 kow
                                                              0.62)
                                           OM*10
                                                                  (5)
                                       where:
kow is the octanol water partition
    coefficient, crnVg
OM  is the organic matter content
    in the root zone, g/g

The octanol-water  partition coef-
ficient is known  or  may be calcu-
lated (7) for most chemicals.
     Three variables in equation 3
are   not   directly   measurable.
These are  the  moisture content in
the unsaturated  zone,  the adsorp-
                                        Recharge  is  the  amount  of
                                   water  that  annually  reaches  the
                                   groundwater.    The  most  accurate
                                   value  for  the  recharge  may  be
                                   49

-------
obtained   from   long-term  field
measurements.  For  Long  Island  a
value of  60  cm per year was found
(16) and  for the midwest  3 to 10
cm  per  year  is  generally  assumed
(12).   However,  the measurements
are  generally scarce.   There also
are  various  ways  to estimate this
parameter such as the Thornthwaite
Mather   procedure  (17).     Also
models  such  as MOUSE  (15) may be
used to estimate this parameter.

     The  average  concentration of
the  chemical  in  the  groundwater
may  be  estimated from  equation  3
using  a  first order  degradation
rate in the  unsaturated  zone  and
neglecting the degradation of  the
chemical in the groundwater.
  * (Z * p * k + GWD * e)]

where:
(6)
Cw   is the concentration of the
     chemical in the groundwater,
     mg/S,
M    is the amount of chemical
     applied to the soil per year,
     expressed in kg/day
     is the half-life of the
     chemical in the soil, days
 '1/2
     Equations 3 and 6 give a sur-
prising insight  in  the concentra-
tion of the chemical that might be
expected in the  groundwater under
steady state  conditions  where the
chemical  is   applied   regularly.
For  example,   for  non-degradable
chemicals   that   have   variable
strengths  of  adsorption  to  the
soil,  the  ultimate  concentration
in  the  groundwater  will  be  the
same  irrespective  of  the  adsorp-
tion  partition coefficient.   The
only difference  will be  the  time
of  arrival  such  that  the  most
strongly  adsorbed  chemical  will
arrive  much later  than  the  more
weakly adsorbed chemical.

     For  chemicals  with  the  same
half-life,  and  different  adsorp-
tion  partition  coefficients,  the
chemical  with  the  higher  adsorp-
tion coefficient will have a lower
concentration  in the  groundwater
because  its travel time  to  the
well is longer.

     Thus,  the  general  assumption
that  the  more  strongly  adsorbed
chemicals   do   not   cause  ground
water problems must now be recon-
sidered.     As  an  example,   in
Minnesota  arsenates used  to  con-
trol a grasshopper outbreak in the
1930's  were first  discovered  38
years later (5).

     Finally,  a  ranking  of  the
hazard  of  the  chemical  may  be
obtained  by dividing the  concen-
tration  of chemical  in  the  well
water by the health criteria stan-
dard (14,20).
         where:

         h is the health risk index
         H is the health criteria,  mg/8,

              For a specific  material  con-
         taining synthetic organics applied
         to  soil,  the  chemical  with  the
         highest  risk  index  is   of   the
         greatest potential  concern.   How-
         ever,  the  chemicals  with a  risk
         index less  than  1 are not  likely
         to leach to  groundwater  in concen-
         trations in  excess  of the  health
         standard a,nd will not likely  pose
                                   50

-------
a potential health  risk.   Further
analysis  (step  2  and 3)  would  be
required  to  quantify the  risk  of
those  chemicals  having   a   risk
index greater than 1,

InputData

     The  input  data  for  the  model
are listed  in  Table 1.   Soil  and
hydrologic  input  parameters  are
site specific such as the depth of
the layer with organic matter,  the
organic matter  content,  the  depth
to  groundwater  and  the  saturated
conductivity  of  the  unsaturated
zone.    The  amount   of  water  re-
charged depends on  the  cover crop
and  the   amount  of  precipitation
received by the area.

     Chemical   input   data    are
dependent on the specific chemical
and  its   source.    The  amount  of
chemical  applied is  a  function of
the use  of  the chemical  (e.g.,  a
pesticide)  or   its   source  (e.g.,
sewage  sludge   applied  to  land).
Pesticide applications are common-
ly  0.5  to  3  kg/ha  annually  (1).
Naylor and Loehr  (8,9)  have  esti-
mated amounts of synthetic organic
chemicals  potentially  applied  to
land  through  recycling  sludge  to
soil.   The octanol-water partition
coefficient,  the  half-life,  and
the health  standard are  specific
to the chemical.

Results

     To  test  the  model  for  its
usefulness   and    its    realism,
several   chemicals   known to   be
present in sludge,  as well as pes-
ticides,  some of which  are  known
to  leaeh  to   groundwater,   were
screened  for   Long  Island   (New
York) and the  midwest  environmen-
tal conditions.   Long  Island  was
selected because it is representa-
tive of  many soil  and precipita-
tion conditions along the Atlantic
Coast and  because  of  our previous
extensive  research with  soil  and
water  interactions  in  that  area
(15).    Midwest  conditions  were
studied  because  of  large  scale
agricultural production.

     The    specific    conditions
assumed for Long Island  were:   1)
sandy soil  with a  hydraulic  con-
ductivity  of  10  m/day;  2)   low
organic matter content (0.5?)  to a
depth  of  0.3  m;  3)   a   depth  to
groundwater of  two meters;  and ^)
an  annual  recharge  of  0.60  m/
year.  A  second set of conditions
were assumed  for  a  midwest  loamy
soil (Table 1).

     Table 2 lists a number of the
organic  chemicals   found  commonly
in  municipal   sewage   sludge  in
important concentrations for which
the  risk  was  calculated.    The
application  rate  of   the  organic
chemical presented  in  Table  2 was
projected  from  the  concentration
of the chemical in combined sewage
sludges  considered to  be applied
to  soil  at rates  to  provide  100
kg/ha of available nitrogen.   The
application  rate   shown   is   the
median  value  of  the  13  sludges
evaluated (8,9).

     To  provide   a  perspective,
several pesticides  known  to  leach
to  groundwater  in   Long  Island
soils were also evaluated  (Table
3).

     The results of the screening
model are shown in Table 4.  Chem-
icals  found  commonly  in  sludge
having a risk index greater than 1
when applied  to a  sandy  soil  are
the small  halogenated  short  chain
hydrocarbons; chloroform, dichlor-
omethane,    trichloroethane    and
                                  51

-------
            TABLE 1.  SPECIFIC DATA FOR INPUT IN THE PROGRAM.

                                                          Input values
-
amount of chemical applied per year
per unit ar*ea ...........
half— life of chemical . . 	
depth to groundwater ........
depth of zone with organic matter . .
yearly average recharge 	
saturated hydraulic conductivity
K octanol— water ...........
organic matter content of root zone .
health criterion by EPA 	


(kg/ha/yr )
(day)
(m)
(m)
(m/yr )
(m/day)
(cmVg)
(g/g)
(mg/1)

Sandy
soil3

Table
2
0.3
0.6
10
Table
0.005
Table

Loamy
soilb

2
3
0.6
0.2
3
2
0.05
2

aLong Island.  bMidwest.
              TABLE 2.  EXAMPLE CHEMICALS PRESENT IN SLUDGE.


Chemical
dichloromethane
polynuclear
hydrocarbon6
(kg/ha)
Application
Rate3
0.022

0.39
(day)
Half-life
of Chemical15
110

44
(cmVg)
Log10
k b
Kow
1.25

5.52
(mg/£)
Health
Standard0
	

	
(mg/O
Carcinogen
risked
1.9x10~s

2.8x10~7
1,4-dichloro-
  benzene           0.016         3.0        3.39     0.40
chloroform          0.0008        93         1.97     	
ethylbenzene        0.062         0.62       3.15     1.4
benzene             0.0038        2.1        2.04     	
phenol              0.026         4          1.46     3.5
di-n-
  butylphtalate     0.046         5          5.2     34
toluene             0.15         -0.62       2.69    14.3
bis-2-ethyl-
  hexylphtalate     1.2           30         5.3     15
1,1,2-trichloro-
  ethane            0.034       1000         2.17
trichloroethylene   0.0125      4 & 321       2.29     	
1.9x10~s

6.6x10~s
  6x10-s
2.7x10-"
aHef. 8, 9.  bRef. 3, 18.  GRef. 14, 20.  ^Protection of human
health from potential carcinogenic effects through Ingestion of contami-
nated (surface) water and contaminated aquatic organisms, with an
increased cancer risk of 1  in 10,000,000.  eTotal polynuclear aromatic
hydrocarbon includes phenanthrene, anthracene, dibenzo (a, h) anthracene,
naphthalene, pyrene, chrysene, and fluoranthene.
                                   52

-------
        TABLE 3.   EXAMPLE PESTICIDES USED COMMONLY IN AGRICULTURE.


Chemical
Aldicarb
Carbaryl
(Sevin)
2,4-D
Atrazine
aRef. 1.
bRef. 6, 18.
°Ref. 1i«.
(kg/ha)
Application
Rate3
3
2

0.5
2



(day)
Half-life
of Chemical13
21, 100
23

15
71




Loglc
kowb
1.15
2.35

1.3
2.2



(mg/£)
Health
Standard0
0.007
0.57

0.10
0.15



  TABLE 1».   HEALTH RISK INDEX OF SOME SYNTHETIC ORGANICS AND PESTICIDES
            APPLIED TO LAND.
Groundwater Health Risk Index
Chemical Sandy Soila
triehloroethylene t / = H (oxidation)
tj/a = 321 (hydrolysis)
diehloromethane
polynuclear hydrocarbon
1,1, 2-tri chlor oethane
1 , ^l-dlchlorobenzene
chloroform
ethylbenzene
benzene
phenol
di-n~butylphthalate
toluene
bis-2-ethylhexylphthalate
aldicarb t / =21 days
t / =100 days
earbaryl
atrazine
2,J<-D
=0
1.2
i»7.6
=0
78.5
«o
1.1
=0
=0
=0
»0
«0
*0
0.05
15.6
»o
0.16
=0
Loamy Soil^
=0
0.0002
O.OOOiJ
=0
9.1
=0
=0
=0
=0
=0
=0
=0
=0
=0
0.0001
=0
=0
*0
aLong Island.  ^Midwest.
                                   53

-------
trichloroethylene.    These  chemi-
cals have  a  relatively long half-
life coupled with a low adsorption
coefficient.   While  the  presence
of  these  chemicals is  well docu-
mented  (11), they  tend to volati-
lize  and  are   unlikely to  leach
into  groundwater  where sludge  is
not  immediately incorporated into
the  soil   (10).   In  an extensive
study   of   groundwater   quality
beneath  a  Michigan   sandy  soil
sludge  application  site,  none  of
the  synthetic  organic  chemicals
were present at detectable concen-
trations  (%).    Thus,  results  of
the model  indicate that monitoring
efforts should  focus  on the short
chain halogenated  compounds.   The
larger,  bulky   molecules  such  as
phthalates  and  other  ring  com-
pounds  appear   to  present  little
risk  to groundwater  contamination
from surface application.

     Of  the  pesticides  reviewed,
only aldicarb was  found to  have a
health  risk  index  greater  than  1,
and then only  for  sandy soil with
little  organic  matter.   Aldicarb
contamination  of  groundwater  has
been  reported  under  such  treated
soils in New York, Wisconsin,  and
Florida.  For the other pesticides
tested in the model,  there appears
little risk to groundwater contam-
ination where  the pesticides  are
used at recommended rates.

Conclusions

     The mathematical model  devel-
oped in this paper  appears  useful
for the rapid  appraisal  of rela-
tive  health  risks  of  synthetic
organic   chemicals   applied   to
soil.    The model  was  based  on
fundamental    relationships    of
soil-water    interactions    with
synthetic    organic    chemicals.
Assumptions  incorporated  into  the
model  were  very  conservative  so
that potential hazards are greatly
overestimated.  Thus, risks should
be  viewed  only  as   an  index  of
potential  groundwater  contamina-
tion.

     The  model  has  been  demon-
strated  to be  useful to  rapidly
assess   which   synthetic   organic
chemicals  pose  the  greatest  risk
to  groundwater.    Using  the  risk
index as a guide,  management prac-
tices  or monitoring  programs  can
be designed to minimize such risks
or  provide a special  emphasis  on
those chemicals having the great-
est risk.

Acknowledgement

     Marjolijn  van  der  Marel  is
thanked  for her  assistance  with
the computer analysis.

References

1.   Anonymous:     1982.    Cornell
     Recommends for   Field  Crops.
     1981   New  York  State College
     of   Agriculture   and   Life
     Sciences.    State  University
     of  New York.   Cornell  Univ-
     ersity, Ithaca, NY.

2.   Briggs,  G.  G.    1973.     A
     simple  relationship   between
     soil  adsorption  of   organic
     chemicals and  their  octanol/
     water  partition coefficient.
     Proceedings   of   the    7th
     British    Insecticide    and
     Fungicide   Conference.    pp.
     83-86.

3.   Callahan,  M.  et  al.    1979.
     Water-related   environmental
     fate  of  129  priority pollu-
     tants.  Vol.  II.   EPA-100/4-
     79-029b.    Office of  Water
                                   54

-------
PIarm i ng    an d    S tan dar ds.
U.S. Environmental Protection
Agency, Washington, D.C.

Demirjian,   Y.   A.,   T.   R.
Westman,  A.  M.  Joshi,  D.  J.
Hop,  R.   V.  Buhl  and W.  R.
Clark.  198*1.  Land treatment
of  contaminated sludge  with
wastewater  irrigation.    J.
Water   Pollution    Control.
Fed. 56:370-377.

Josephson, J.  1976.  Quality
assurance   for   groundwater.
Environ.  Sci.  Technol.  10:
226-227.

Jury,  W.  A.,  W.   F.  Spencer
and W. J.  Farmer.  1983.  Use
of models for assessing rela-
tive   volatility,   mobility,
and persistence of pesticides
and  other trace organ!cs  in
soil systems.   pp.  2-43.   In
J.   Saxena   (Ed).      Hazard
Assessment    of    Chemicals.
Current Developments.    Vol.
2.    Academic  Press.    New
York.

Lyman, W.  J., W. F. Reehl and
D.   H.  Rosenblatt.     1982.
Handbook  of  Chemical  Prop-
erty    Estimation    Methods.
McGraw-Hill   Book   Co.,   New
York.

Naylor,   L.   M.  and   R.   C.
Loehr.     July/August  1982.
Priority pollutants in munic-
ipal sewage sludge.  BioCycle
23:18-22.

Naylor,   L.   M.  and   R.   C.
Loehr.      November/December
1982.  Priority pollutants in
municipal   sewage   sludges.
Part II.  BioCycle 23:37-42.
10.   Overcash,   M.    R.      1983.
     Specific  organic  compounds.
     p. 212.   In A.  L.  Page  et.
     al.   (Eds.)  Utilization   of
     Municipal   Wastewater    and
     Sludge  on  Land.    University
     of California,  Riverside,  CA.

11.   Pye,  V.  I., R.  Patrick  and
     J. Quarles.   1983.   Ground-
     water  Contamination  in  the
     United  States.   University of
     Pennsylvania  Press,   Phila-
     delphia,  PA.

12.   Rehm, B. W., S.  R.  Moran  and
     G.  H.   Graenewold.     1982.
     Natural  groundwater recharge
     in an upland area  of central
     North  Dakota,    U.S.A.     J.
     Hydrol. 59:293-314.

13.   Sawhney,   B. L.   and  R.   P.
     Kozloski.  1984.   Organics in
     leachates    from    landfill
     sites.     J. Environ.  Qual.
     13:349-352.

14..   Sittig, M.   1981.   Handbook
     of Toxic and Hazardous  Chem-
     icals.    Noyes  Publications.
     Park  Ridge,  NJ.

15.   Steenhuis,  T. S.,  M.  van  der
     Marel and S. Pacenka.   1984.
     A pragmatic model  for   diag-
     nosing     and     forecasting
     groundwater    contamination.
     Proc.  Practical   Application
     of    Groundwater     Models.
     August  1984.  National  Water
     Well  Association.

16.   Steenhuis,  T. S., C. Jackson,
     S. K.   J.   Rung  and  W.   H.
     Brutsaert.    1985.    Measure-
     ment  of  groundwater  recharge
     on Eastern  Long  Island.   J.
     Hydrology.   In  Press.
                              55

-------
 17.  Thornthwaite,   C.   W.   and
     J.    R.    Mather.       1957.
     Instructions  and  tables  for
     computing-  potential  evapo-
     transpiration  and  the water
     balance.      Publ.  Climatol.
     Lab.  Climatol.  Drexel Inst.
     Technol. 10:185-311.

 18.  Trabalka,  J.  R.   and  C.  T.
     Garten,  Jr.   1982.  Develop-
     ment  of  predictive models for
     xenobiotic bioaccumulation in
     terrestrial        ecosystems.
     Final  Report,  Contract  No.
     @-7H05-eng-26.     Oak  Ridge
     National  Laboratory.   Envi-
     ronmental    Sciences    Div.
     Publication  No.  2037.   Oak
     Ridge TN. 256 pp.

 19.  U.  S.  Environmental  Protec-
     tion  Agency.   1982.    Fate of
     priority  pollutants in  pub-
     licly  owned  treatment works.
     EPA HHO/1-82/303.      Efflu-
     ent    Guidelines    Division.
     WH-552.  Washington, D.C.

 20.  U.  S.  Environmental  Protec-
     tion  Agency.   1980.   Water
     Quality  Criteria  Documents.
     Federal    Register    *)5:321:
     79318-79379.
              Di sclaimer

The work described in this paper was
not funded by the U.S. Environmental
Protection Agency.  The contents do
not necessarily reflect the views of
the Agency and no official endorse-
ment should be inferred.
                                    56

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PHYSICAL AND CHEMICAL ATTENUATION PROPERTIES OF TIDAL MARSH SOILS
                AT THREE MUNICIPAL LANDFILL SITES

      Steven E. Panter, Richard Harbour, Angelo Tagliacozzo
                       Gibbs & Hill, Inc.
                          11 Penn Plaza
                      New York, N.Y.  10001

                            ABSTRACT

    The  hydraulic  conductivity,  (K), cation exchange capacity,
(CEC), and total organic carbon, (TOC),   of  soils  composed  of
clays  and  silts  are thought to make them effective barriers to
contaminants in groundwater, and media capable of  sorbing  heavy
metals and organic compounds.  Tidal marsh deposits consisting of
silts and clays and underlying sands at three municipal landfills
were  tested  for pH, CEC, TOC and K.  Results were compared with
heavy metal  and  organic  compound  concentrations  measured  in
groundwater  samples  above  and' below the tidal marsh deposits.
Evaluation indicated that the tidal  marsh  desposits  were  less
effective  in  removing  heavy  metals  than  expected,  but were
effective in  preventing  migration  of  organic  compounds  into
underlying  sand  deposits.   Total volatile organics, (TVO), and
total halogenated volatile organics, (TVHO),  were  reduced  from
72,440 ug/1  to  27 ug/1, and 867 ug/1 to <10 ug/1 in some cases.
Organic carbon content in the tidal marsh deposits averaged 2.2%.
Decomposition of the organic fraction yielded acids which reduced
pH to as low as 3.3 Consequently, the tidal marsh  deposits  were
ineffective  in  removing heavy metals, but remained effective as
an  hydraulic  barrier.   Our  studies  showed  that  the   soils
effectiveness  to  mitigate  groundwater  degradation  from heavy
metals and organics  can  be  gauged  by  evaluating  the  soil's
chemical and physical properties.
INTRODUCTION AND PURPOSE

     Tidal marsh deposits
consisting of organic silt
and clay are generally con-
sidered effective hydraulic
barriers to ground water
flow and having the adsorp-
tive capacity to retain dis-
solved heavy metals and or-
ganics.  However, natural
factors may alter, negate
or reduce these properties.
Such factors include:

• Soil pH,  cation exchange
  capacity, and total organic
  carbon

• Inclusions in the deposits
  (pockets of sand and/or shell
  fragments)

• Discontinuities within the
  silt and clay deposit
                               57

-------
• Hydraulic conductivity of
  deposits

     This paper addresses our
findings on soil pH, CEC, and
TOC and their effects on the
adsorptive capacity of tidal
marsh deposits.

     Gibbs & Hill completed a
hydrogeologic study at three
municipal landfills located
in the New York Metropolitan
area.  The investigation aimed
at assessing the impacts of
landfill-generated leachate
on local aquifers and bay
waters.

     At each landfill, the
stratigraphic sequence
consisted of the following
(see Figure 1):
               Figure 1

         LANOFHX STHATK3FIAPHIC SEQUENCE
            Upper Glacial Sand
       Sea Level
« Municipal waste: 30' to 120'
» Tidal marsh deposits: 5'-12'
* Hydraulic fill: 5f
• Wisconsin-Age glacial out-
  wash sediments  (Upper Glacial
  sand aquifer) to 150'
• Other Pleistocene and Cret-
  aceous Sediments
» Pre-Cambrian crystalline
  bedrock

    The aquifers  underlying
each site are:
 • Water Table Aquifer:
   (Leachate Mound)
 * Confined Aquifers: Upper
   Glacial, Jameco, Magothy,
   and Lloyd (top to bottom)

   Of these aquifers, the study
   focused on the Upper Glacial.

     Ground water level measur-
 ments within the aquifers varied
 as follows:

 • Leachate mound: 8' to 11"
   MSL (Mean Sea Level)
 • Upper Glacial Aquifer: -2 to
   -6' MSL

      The difference between
 piezometric heads caused a down-
 ward driving force, which
 resulted in leakage of ground
 water and landfill leachate
 from the leachate mound into
 the Upper Glacial Aquifer,
 through the tidal marsh deposit.

    Chemical soil testing was
performed on samples from the
tidal marsh deposits and the
Upper Glacial sands.  The tidal
marsh deposits consisted primarily
of silt and clay with occasional
lenses of fine sand and shells.
Organic content included humic
materials and layers of peat. The
Upper Glacial sands were composed
mainly of sand and gravel.

     Municipal refuse makes up
the bulk of the material disposed
at the landfills.  Daily disposal
rates run as high as 9,500 tons
at the largest landfill, 297
acres. Waste oil was applied to
landfill roads in earlier years
to control road dust.  Illegal
dumping of hazardous wastes
occurred at all three sites; and
5,000 fifty-five gallon drums
containing wastes of paint pig-
ments and solvents, were recently
unearthed at one location and
                                 58

-------
waste oil laced with PCB's
at another.
Aquifer between -110 and -140
feet below mean sea level.
APPROACH

     Fifteen soil samples were
obtained during the install-
ation of ground water
monitoring wells.  Samples
were collected using a
steel split-spoon sampler
and undisturbed samples
were retrieved using a
brass thin wall "shelby"
tube.

     Samples were sent to the
lab and analyzed for:

•  pH
*  Cation Exchange Capacity
     (CEC)
•  Total Organic Carbon (TOC)
•  Hydraulic conductivity (K)
•  Grain size distribution and
     identification.

     Well water samples from
above (U wells), and below (S
wells),  the tidal marsh depo-
sits were compared for heavy
metals and organics.  The
results were then examined
against soil sample test
results, and the physical
character of the tidal marsh
deposits-  We gauged the
effectiveness of the tidal
marsh deposits to filter
heavy metals and organics
based on these comparisons.

      A total of 65 wells
were used in this study.
Wells above the tidal marsh
deposits numbered 32 and were
located between +1.0 and -7.0
mean sea level - just above
the deposits.  The 23 S wells
were placed between -30 and-40
feet below mean sea level in
the Upper Glacial Aquifer.
The remaining 10 wells were
placed in the Upper Glacial
EVALUATION FACTORS/PROBLEMS

     A number of factors are
extremely important to consider
when assessing the potential of
the deposits to mitigate wastes.
First, the information obtained
may be used to obtain a relative
measure of effectiveness against
chemical migration.  Second, in
order to properly evaluate the
soil chemical data, it is essen-
tial to get an accurate picture
of the deposits.

     Large voids, windows or sig-
nificant layers of coarse materials
allow ready movement of leachate
from one layer to another. If these
are not recognized and their
dimensions and character known,
even favorable CEC, pH and TOC
data may yield erroneous inter-
pretations.  In addition, undis-
turbed samples should be examined
to see what portions are the most
frequently occurring, and which
portions show the outside range
of variability in the samples.
Third, it is important to test CEC
at ambient pH in addition to pH 7.
This is important because the soils
should be evaluated under in-situ
conditions, conditions unlikely to
change in the near future.

     One problem we had was the
lack of leachate extraction analy-
ses on the soil samples.  This
information would have given a
better account of where the metals
and organics were moving and how
much was being sorbed.

RESULTS
Cation ExchangeCapacity

     The tidal marsh deposits
samples had CEC values of 7.0 to
237 milliequivalents (me)/100g
soil, with most values falling
                               59

-------
between 39  and 184 me/lOOg,
These values  are relatively
high and were attributed to
humus content of the  soil.

      CEC values in the Upper
Glacial sand  ranged from 0.6
to 59 me/lOOg,  with an average
CEC  of 22 me/lOOg.

Overall,  CEC  values in the
tidal marsh deposits were one
order of magnitude greater
than in the Upper Glacial sands
(See Table 1).
             TABU; IA
          TIDAL KMtSH DEPOSITS
        SOILS CUX!U*niY> pH, TOC, CEC
*«Bpl«
Put*


Will Ha,
F»

TOC, l»«y

etc.
Be ^/ 1009
• p* 7

Material
Typ«





B



L.r.JflU 1 1 Undfill 2


urioia
1,6

27,100



|1««
I


drill


14,900



237

IKL-1 |H£.-2
1 1
1
I
HF2Q1 IHJ203U
3.S 5. 5

1.60O 20,800



24 175
1
SH-SC JHt-Ct.
1


HE202S
3,5

7,580



39

CL

Landfill 3


1
1
HE203S IHE203S
t
4.S

1,01



7

ML-3

13,3
1
Q 125,500
1
1
1
( ISO
1
(ML-*
1
H*K*rial Typo:
tb-li
IU.-2
SJt"SC;

tC-CLi
Cl*f

Ht-Jl

m*4t
Soft 9C*y wilt, sowe clay, trace shell fragments
ioft srey alls, little clay, trace p«at.
Olive brcvn nediu£l aanei, aotsB «llt grueling to we
9tad«d tt»nd with tr«c« silt, clay and gravel.
lilt and Clay with an elqht inch layer of shell
Clay with Now* silt, traco fine sand, grading to
••nd and little allt.
Silt with little clay and shell frft^acnta, trace
{in* saml.
lilt atul clay.


11

fragments.
fino

very


             TM3LE IB
        UPPER GLACIAL SANDS AQUIFER
        SOILS CHEMISTRYi pH, TOC, CCC
X&*|3l*
P*«»

I.nndfUl

I
Will va, IHTIO:D-
1
f»
toe, «»/«

etc.
B*O/10O»
• pH 7
H*t*CI«l
3.S
ISO



20
M-l
!«>• I


urns

6.6
410



19
SX-2




tmois

6.0
7SO



1S2'»
St-SH
Lindflll 2


W201

5,9
600



O.6
SW-SP
t


HP203

6.1
420



1
SM



HP204

6.S
960



13
»S-3

landfill 3
1
I
HE202S JHE204S
1
3,0 1 8.3
320 | 780
1
I
1
47 1 4
i
S«-4 (SH-SW
1
 Above Tidal Harsh (Deposits - Hot part of Upper Glacial Sands


'* feasible saapie eontanination

 K*l«n*l Typ«[

 SK*lt irevn Cine ED nediun tand, dense, little ailt.
 •LH*2t If own nedlun to coarse atnd, noderately dense, little ailt,
 SF-W: Orey iMdiiMt to coarse sand, slightly dense with trace silt
    and ssae gravel,
 •W-SFi Crey sMdiuiK to coarse sand, slightly dense, trace silt and
    fine gravel,
 94:  Fine to coscse sand with trace silt and fine gravel.
 *H*3t Olive brovn »ediu» to coarse sand, loose, with trace silt
    and brick Crageents.
 S*f»4! Fine/ to (tedium aand with soao silt.
 SK*fiW; Fine to coarse sand with trace silt.
                                          Soil pH

                                               Low  values for soil pH
                                          (acid conditions)  indicated in-
                                          creased potential  for mobility
                                          of metallic ions.

                                               Tidal  marsh deposits samples
                                          exhibited soil pH  values of 3.3 to
                                          5.5,  with most of  the samples  being
                                          extremely acid (pH <4.5) (USDA,
                                          1951).   pH  in the  Upper Glacial
                                          sands ranged from  extremely acid to
                                          moderately  alkaline (pH 3.0-8.3),
                                          but most  samples were in the
                                          medium to slightly acid range
                                          (pH 5.6 to  6.6).

                                               Lower  pH values  in the
                                           tidal marsh deposits were  attri-
                                           buted to acids produced from
                                           decomposing organic  matter.

                                               The  pH in groundwater  samples
                                          above the tidal marsh deposits
                                          ranged between 6.3  and 7.8.  Below
                                          these deposits they ranged  between
                                          6.2 and 7.4.
                                         Soil  Organic  Carbon

                                               The organic carbon content
                                         affects a soil's potential to
                                         remove contaminants by provid-
                                         ing sites for ion exchange
                                         and adsorption,  as well as en-
                                         hancing its capacity  to filter
                                         out suspended particles,  such
                                         as PCB's (Weber et al,  1983).
                                              TOG content of the  tidal
                                        marsh deposits ranged between
                                        0.10  to 2.7%,  with a average of
                                        approximately  2.2%.
                                              The TOC  of the Upper
                                        Glacial sands was much lower,
                                        ranging between 0.03  and 0.16%,
                                        with  an average of 0.07%.
                                  60

-------
Relationship betweenpH, TOG and
CEC
     A balance exists in the soil
between the pH, CEC and organic
matter content.  The two compo-
nents of CEC are:

• pH-independent CEC:

     This component is deter-
mined by the cations which are
fixed in the soil mineral
during formation.

• pH-dependent CEC:

     This component is related
primarily to the organic fraction
of the soil, particularly organic
functional groups associated
with the humus.  As the pH
increases above 5, these groups
increase their ability to adsorb
metallic ions.

     ..The tidal marsh deposits in
our study included both CEC com-
ponents.  Four samples with TOC
content greater than 1% had high
CEC values of 175 to 237 me/lOOg.
Three samples with less than 1%
TOC content had CEC's of 7.0 to
39 me/lOOg.

     The Upper Glacial sands had
little or no organic matter
content, and low CEC values.  TOC
ranged from 0.03 to 0.1% and CEC
values ranged from 0.6 to 59.
me/lOOg.  Consequently, CEC values
in the Upper Glacial sand layers
were mostly pH-independent.

Soil Attenuation Potential

      Soil attenuation potential
results from a combination of
chemical and physical factors.
Due to the large differences in
pH, CEC, TOC and physical charac-
teristics, attenuation in the
tidal marsh deposits and Upper
Glacial sands in our study
differed as discussed below.
Tidal Marsh Deposits

      Attenuation potential

appeared to be limited. Despite
thickness (5* to 12') and
relatively high TOC >1%), the
water quality data did not show
any consistent reduction of heavy
metals attributable to this layer,
as evidenced by a comparison of
heavy metal concentrations between
water samples from above and below
the tidal marsh deposits.

     At landfill 1, Ni concen-
trations at 102U were 50 ug/1 and
276 ug/1 at 102S.  In well 104U,
Cr concentration was 38 ug/1,
while at 104S it was 32 ug/1.  At
landfill 2, Sb concentrations in
101U were 540 ug/1 and 500 ug/1
at 101S.  At 103U Cd was 28 ug/1
and 38 ug/1 at 103S (See Table 2).

     Heavy metal concentrations in
groundwater samples were generally
one order of magnitude greater
than background bay water samples
taken near the bay center and in-
let.  Background bay water sam-
ples taken near the landfill were
generally close in heavy metal
content to the groundwater samples.
Tidal fluctuations, which bring
bay water through the Upper
Glacial sands toward the land-
fills, may explain why some wells
show concentrations of heavy
metals which are greater below
the tidal marsh deposits than
above.  It is also possible that
very low pH levels are causing
a release of metals at some
locations.

     Measurements taken  at moni-
toring wells above the tidal marsh
deposits showed the effect of
tidal fluctuations on the leachate
mound to be negligible.  Below
the tidal marsh deposits ground
water levels ranged between 0.95
and 2.57 feet.
                               61

-------
          TABLE 2

1S84 CROUNOWATCR QUALITY, (ug/l and pH In units)

         LANDFILL 1
Reduction and  subsequent in-
creased mobility  of  cations
caused by saturated  (anerobic)
Mil.
Hfl
101 U
191 >
102 U
101 *
10) U
10] S
10
(40)
140
40
120
100
220
60
120
120
180
MDFIL
Po
(40)
100
L
80
80
80
60
260

100
L
nit
— .c-
Hg
(0.2)
L
L
L
L
L
L
L
L
L
L 2
Hg
(0.2)
2
L
1
L
1
1
1 L
L
L
L
L
4
L 3
Hg
(0.2)
L
L

HI
(40)
94
92
50
276
L
210
160
274
198
198
HI
1(40)
112
1
1 94
1
48
1 56
110
224
188
60
90
HI
(40)
-


L
L
L
52
50
240
1
L
L 1 -
1
So
(2)
L
L
L
L
L
L
L
L
L
L
1
So
1(2)
L
L
L
L
L
L
L
L
L
So
(2)
-


L
L
L

-
-
Ag
(40)
L
L
L
L
L
L
L
L
L
L
1 Ag
1(40)
!
L
L
L
L
L
L
L
L
L
(48)
-


L
L
L

-
Th
(100)
220
120
340
L
240
Th
(100)
L
L
L
L
L
140
L
L
L
Th
(100)
-


L
L
340

Zn
^
48
30
!
521
1
681
H
3581
521
78
43
1
IZn
72
46
28
62
66
104
56
96
56
Zn
pH conditions.
7.8
6.6 • Physical gaps and inclusions of
6-8 more permeable sediments in the
^•7 tidal marsh deposits allow
I'l leachate to percolate directly
7!5 into the Upper Glacial sands.
7.0
7-7 Large differences in concen-
trations of total volatile or-
! H ganics were found in water above
and below tidal marsh deposits.
6.7 It appeared that the relatively
7-2 high TOG content of the tidal
7-2 marsh deposits caused this reduc-
7]0 tion; a result of the affinity of
6.7 organic material in the deposits
7.4 for hydrophobic compounds contain
6-2 ed in leachate (See Table 3).
7.0
7.0
TABLE 3
TOTAL VOLATILE ORGANICS (TVO)
66 7.5 TOTAL VOLATILE HALOGENATED
» 5-7 ORGANICS (TVHO)
70 6.3
« *'l Land- TVO TVHO
72 7.. fill Well (10) (10)
1401 6.9
m 7-3 3 3 N S 246 L
'" !'7 3 3 N U L L
- uo4 7^4 3 101 U 49,083 31,775
3 101 S 3,390 2,549
3 103 U L L
	 , 3 103 S 181 L
removal by the tidal marsh de-
posits is  believed to be due to:

•  High acidity in  the tidal
  marsh deposits which lowers
  the effective CEC.

•  High concentrations of Na,
  Al and Mn present  in the  bay
  water,  and released from  soil
  at low pH, compete  for
  adsorption sites.
                                       ™
                                  2
                                  2
      201 U
      201 S
72,440
27
867
L
                                 L  = Less than Detection  Limit
                                 ()  = Detection Limit
                                 U  = Well in Leachate Mound
                                 S  = Well in Upper Glacial  Sand
                                 Values in ug/l
                          62

-------
Upper Glacial Sand

     The Upper Glacial  sand layer
has a very low potential  for-
attenuating the passage of  con-
taminants because of:

• Large particles size  (low clay
  content) and low CEC
 Weber, W.J., Jr., Voice,  T.C.
 Pirbazari, M., Hung
 G.E., Ulanoff, D.M.,  1983
 Sorption of Hydrophobic
 Compounds by Sediments,
 Soils and Suspended  Soils
 II, Water Resources,  Vol.
 No. 10, pp. 1443-1452.
• Low organic matter  content

    These factors  result  in a medium
which has little or no  capacity
to attenuate wastes.
SUMMARY

    Overall attenuation  potential
in the tidal marsh deposits was
low. Unfavorable pH, high con-
centrations of competing ions,
and anerobic conditions  resul-
ted in deposits which  have a low
capacity to attenuate  heavy metals
in leachate. The tidal marsh
deposits apparently  accomplished
some removal of dissolved organic
compounds, but the most  signifi-
cant effect was the  physical
restriction of the vertical flow
of leachate from the landfill to
Upper Glacial sand.

ACKNOWLEDGEMENTS

    The authors would  like to
thank Mr. Joseph Turcotte of
Gibbs & Hill, Inc. for his
comments and direction.
            Disclaimer

The work described in this paper was
not funded by the U.S. Environmental
Protection Agency.  The contents do
not necessarily reflect the views of
the Agency and no official endorse-
ment should be inferred.
REFERENCES

United States Department of
Agriculture Soil Conservation
Service, Soil Survey Hand-
book, No. 18, 1951
                               63

-------
    LAND DISPOSAL OF WASTES CONTAINING  POLYNUCLEAR AROMATIC COMPOUNDS

                              Ronald  C.  Sims
                      Utah Water  Research Laboratory
                           Utah State University
                             Logan, UT   84322
                                 ABSTRACT
     This research  project  investigated the  treatment  potential  of  soil
systems  for  polynuclear  aromatic  compounds  (PAHs)  identified  in  wastes
from  industrial  and  municipal  sources.   A  protocol for  obtaining  the
soil  assimilative  capacities  of  PAH compounds,  including  transformation
of mutagenic characteristics was  developed.   The protocol  included:   (1)
incubation,   (2)  characterization/identification,  and  (3)   determination
of mutagenic  potential..   The protocol  involved  interfacing  high  perform-
ance  liquid  chromatography  (HPLC)  for  compound  and  metabolite  character-
ization with the Ames Salmonella typhimurium mammalian microsome mutageni-
city  assay for  determination  of  genotoxic  potential  of PNA  compounds  and
transformation products in  single constituent systems and in complex
waste:soil mixtures.

     Kinetics of transformation were related to  PAH  structure.  The range
of  half-lives  was similar for  low  and  high  soil loadings   (19-190 days)
while the initial  soil  concentration varied over  a  range of 0.07  to  147
ppm.  The initial  rate of degradation varied by a factor of  2000.   Results
of engineering management options suggest  that it may be possible  to
influence the  degradation rates  of PAH constituents  with   pH  amendment,
analog  enrichment,  complex  substrate  amendment, and  moisture  control.
Results for  mutagenicity testing  indicate  that  the  polar  class  fraction
of  PAH  metabolites may  be mutagenic,  and may  leach  through  soil  under
saturated conditions,  but proceeds through  a pathway  of  detoxification  and
degradation  which  can  be controlled  and managed.   Results of  studies
obtained thus far  indicate that,  with a better understanding of  soil:waste
processes,  it  will  be possible to  accomplish  safe  ultimate  disposal  and
ensure  the  protection of  public  health  at reasonable cost to  society.


INTRODUCTION                           concept of land treatment. Hazardous
                                      waste land  treatment  (HWLT)  can  be
     Land disposal  was  defined  and   considered as the  intimate mixing or
approached  in  this  study under the   dispersion of  wastes  into the upper
                                    64

-------
zone of the  soil-pi ant  system  with
the objective of microbial  stabili-
zation,   detoxication,   immobiliza-
tion, or  plant  treatment.  HWLT,
with proper  design  and  management,
must  lead to  an  environmentally
acceptable assimilation of the waste
which  ensures  protection  of the
public health.

     Polynuclear  aromatic  hydrocar-
bons  (PAH) include  a group of or-
ganic priority  pollutants  of criti-
cal environmental and health concern
due  to  the  following  characteris-
tics:   (1)  chronic  health  effects
(carcinogenicity),  (2)  microbial
recalcitrance,  (3) high bioaccumula-
tion potential, and  (4)  low removal
efficiencies  in  traditional  waste-
water treatment processes  (2).  PAH
compounds  have  been  identified and
summarized for  a  variety of domestic
and  industrial  liquid  wastes and
solid residues  (5,7,9).   Based  on  a
comprehensive review  of  the litera-
ture  and  laboratory treatability
studies,   Sims  and  Overcash (8)
summarized the  behavior  and  fate of
PAH compounds in soil systems.  The
potential   for  effective  treatment
and  safe  ultimate  disposal  of PAH
compounds  is  significant with regard
to land  treatment.

     Recently promulgated  hazardous
waste  land  treatment  regulations
established by  the U.S. Environment-
al Protection Agency  (40 CFR section
264) requires a permit to  operate  a
HWLT facility.  Requirements specify
that hazardous  constituents contain-
ed  in  a waste to  be land treated
must be  degraded,  transformed,
and/or immobilized in  the soil
treatment  zone.  A  treatment demon-
stration must be conducted  in  order
to  specify  design  and  management
requirements  including:    (1)  waste
application rate, (2) waste applica-
tion frequency,  (3)  waste  applica-
tion method,  (4)  measures to control
soil pH,  (5) measures  to  increase
microbial  activity,  (6)  measures  to
increase chemical reaction,  and  (7)
measures to  control  soil  moisture.
PURPOSE
     Research  is needed to  provide
engineering  design  and  management
information  for  land treatment
systems receiving wastes containing
PAH constituents.   Because  of  the
diverse  inputs  of  site  character-
istics,  waste constituents, soil
reactions,  and assimilation  capaci-
ties,  development of  a methodology
for using  information concerning
the behavior  and  fate of PAH con-
stituents in land treatment  systems
is required.
     For this research  effort,  in-
formation was  obtained  concerning:
(1) waste loading rates,  (2)  rates
of  degradation,  (3) measures  to
increase microbial  activity,  and
(4)  mutagenic   characteristics
transformation  for  soil  incubated
priority  pollutant  PNA  compounds.
A  protocol  for obtaining  this
information  was developed   and
evaluated.   The three-step protocol
included:  (1)  incubation,  -(2)
characterization/  identification,
and (3)  determination of  mutagenic
potential.    The  protocol  involved
interfacing  high  performance  liquid
chromatography  (HPLC) for  compound
and metabolite characterization with
the  Ames  Salmonella  typhimurium
mammalian  microsome  mutagenicity
assay for determination of genotoxic
potential of  PNA  compounds  and
transformation  products  in soil.
                                    65

-------
APPROACH

Incubation

     PNA  compounds  were  incubated,
singly  or in  a complex  waste,
in  an  environmentally controlled
chamber   in  glass  soil  reactors.
Environmental  parameters  that  were
controlled  included  temperature
(25°C),   light  exposure  (dark to
prevent  possible  photodegradation,
or  light  to encourage photodegrada-
tion),  and soil  moisture  as  percent
field capacity.

Chemical  Characterization
with HPLC

     Procedures  for  extraction  and
analysis  of  PAH compounds were
based on the high performance liquid
chromatography  procedure  for
analysis   of PAH  compounds in  water
samples  (4).    HPLC was  used with
acetonitrile-water  as  the  mobile
phase,  and  a C-18 Perk in Elmer
reverse phase  column was used as  the
stationary phase.   PAH  compounds
and  metabolites  were characterized
with  a  UV  detector at   a  wave
length  of 254  nm.

     A  subset  of soil  extracts  was
fractionated   using  a C-8 prepara-
tive Lobar size-A prepacked  column.
Polarity classes   of  degradation
products   were  collected  in   aceto-
nitrile-water, evaporated, and
redissolved in dimethylsulfoxide  for
the Ames  assay.

Mutagenicity Evaluation

    The Ames Salmonella typhimurium/
mammalian  microsomemutagenicity
assay (6) was  used  to determine  the
genotoxic potential  of complex
extracts  (unfractionated)  as  well as
parent  compounds and biodegradation
products  obtained with the fraction-
ation  procedure described  above.
Enhancement  of Microbial Activity
     Potential  engineering  manage-
ment options for stimulating  micro-
bial activity include analog enrich-
ment,  complex  substrate  enrich-
ment, nutrient  addition,  surfactant
addition,  pH   adjustment,  and
moisture  adjustment.   The  options
may  provide tools  for increasing
the  rate  of biodegradation of PAH
constituents and  therefore  increas-
ing  the  soil  assimilative  capacity
for  these constituents.   Phenan-
threne was used as an analog enrich-
ment,  at  a concentration of 1000
mg/kg soil.  Raw manure addition to
soil reactors  was the  complex sub-
strate enrichment and was calculated
based on nutrient content.   Nutrient
addition   including nitrogen  and
phosphorus was added  as  the salt
solution recommended by Hoagland and
Arnon  (3).   To investigate  the
effect  of  surfactant addition  on the
soil assimilative  capacity for PNA
constituents, Triton-100  surfactant
was  used  at 2  ml/200 gm soil dry-
weight.    For  pH adjustment, CaC03
was  used  to neutralize  a Norfolk
fine sandy loam  (pH  = 6.1); soil pH
was adjusted to  7.0.  The  effect of
soil moisture  on  PNA  assimilation
capacity was investigated  with two
soil moisture  ranges,  20-40 percent
field  capacity and  60-80 percent
field capacity.
     Chemical  and mutagenic  data
were  subjected  to  analysis  of
variance,  and when  significant
differences  at  the 5  percent  level
were  found,  Duncan's  New  Multiple
Range Test was  employed to  separate
means.   The  statistical  procedures
were  performed  using  standard
package  programs  of  Statistical
Analysis  Systems-76 (1).
                                   66

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PROBLEMS ENCOUNTERED

     One  problem concerned the type
of  soil  reactor/sampling  approach
used.   Because  of the difficulty of
achieving  completely homogeneous
mixtures  of soil  and  waste  or soil
and  PNA  compound,  accurate  repro-
ducibility  for  results  of subs amp-
ling  soil  from one reactor  is
difficult  to achieve.   Therefore,
the entire  contents  of  each  glass
soil  reactor  was  used  for each
sampling  event;  replicate soil
reactors  were prepared  in  order  to
obtain   samples  through  time.
Triplicate  reactors  were used  for
each sampling event.
RESULTS

     Based on a comprehensive review
of the  literature and on  labora-
tory treatability  studies,  initial
rates  of transformation  of  PNA
compounds  in  soil  as  a function of
initial  soil  concentration  based
on first  order kinetics are  pre-
sented  in Figure 1.   These  data
were  corrected for  variation  in
temperature  using  an  Arrhenius
equation with coefficients developed
from PNA  data  to  a  temperature of
20"C.   Rates  were  normalized  to
micrograms PNA  transformed per gram
soil  dry-weight  per  hour.   The
general  trends shown in  Figure 1 can
be summarized as follows:  (1) for a
given PNA  compound, the  initial rate
of  degradation  increases with  in-
creasing initial soil concentration,
and  (2) within the  class  of  PNA
compounds  the initial rate  of
degradation  decreases  with  in-
creasing  number of  fused  benzene
rings (or  molecular weight).

     Results  for  PNA  degradation
kinetics  from laboratory  studies
and from  the  literature  indicate
that most PNAs  have reasonable,
finite  half-lives in  soil systems at
the  concentrations evaluated.
Kinetics  of degradation  were  found
to  be  related  to  PNA  structure.
Arranging  PNAs by number  of  rings
indicates  that  there  are  distinct
statistically  different  groups  of
PNA compounds.   The  range  of  half-
lives  is  similar for  low  and  high
soil loadings   (19-190 days)  while
the initial  soil  concentration
varies  over a  range  of 0.07  to 147
ppm  (2000  fold).    However  the
initial  rate  of degradation  varies
by a factor of  2500.


    Results   of  experiments  with
engineering  management  options
suggest  that  it may  be possible to
influence  the  degradation   rates
of  PNA  compounds.   The effect  of
several  amendments on the  degrada-
tion of benz(a)pyrene is presented
in  Table  1.    The  degradation  of
B(a)P,   a  five  ring  PNA  compound
which  is considered to be cometabo-
lized,  i.e.,  cannot serve  as  a
source  of  carbon and  energy for the
growth  of  microorganisms, appears to
be  influenced  by pH   adjustment and
analog  enrichment.    Statistical
analysis  of  the data  indicated
significant  differences  among  the
treatments, as shown in  Table 1.

    The  effects  of  simultaneous
addition  of   a  complex  substrate
amendment, raw manure,  and  pH
adjustment on   degradation  kinetics
for a complex  waste  containing PAH
compounds  is  presented in  Table 2.
Manure provided an  inoculum  of
microorganisms and degradable
organic  carbon sources  for  soil
microorganisms.   pH   of  the  waste:
soil mixture was adjusted  from 6.1
to  7.5.   Results are  presented for
                                  67

-------
                                 10'
                                 10°
                                                    •— OI8ENZ {•. j) ACR101KE

                                                    •*	 DlBENZd.h) AHfKRACCNE

                                                    •— OIBENZOfUBAH

                                                    a— oteEHZormopHENE

                                                    «— FLUOflCNC

                                                    V	 FLUORAHtHENE

                                                    •	 NAPHTHALENE

                                                    -	 PHCHAHTHAEHE

                                                    •	 PTKEHE
                                  10-'   10°   10'   IO1    103   10'   I0>

                                    INITIAL CONCENTRATION (o5/g-Jr/ -!.)
  Figure  1.    Rates of  Transformation  of PNA Compounds in  Soil  as  a
                  of  Initial  Soil  concentrations.
                                                                                function
                    10-

                     9-
                  CE

                  o
                  2
       TIME JO C«S     J
       • 221 aEVE3TiNTS/
-------
PAH compounds identified and quanti-
fied in waste:soil  mixtures without
and  with  the  amendment  described.

     Results presented in Table  2
indicate  that  degradation of all
PAH  compounds  was  affected by the
amendments.   PAH  half-lives were
greatly  reduced  compared  with
half-lives  in  unamended  soil.
Table 1.   Effect  of  amendments on
          benz(a)pyrene degradation.
Treatment
None
Nutrients
pH Adjustment
(5.2 to 7.4)
Surfactant
Analog enrichment
with phenanthrene
Half-life
(days)
90 Aa
81 A
64 B
87 A
64 B
aValues  are  means  of three  repli-
cates.   Means followed  by same  let-
ter are  not significant  at the  0.05
level.
                                          The effects of moisture amend-
                                     ment  on the  degradation  of  pure
                                     PAH compounds applied to soil  batch
                                     reactors is  presented  in Table  3.
                                     For  all  three  PAH  compounds evalu-
                                     ated.,  degradation  rates were  im-
                                     proved  by  adjustment of  soil  mois-
                                     ture  from  20-40 percent of  field
                                     capacity to 60-80  percent.   Thus
                                     results  for  amendment  additions  to
                                     PAH compounds present as individual
                                     constituents or in  complex  waste in
                                     soil   indicate that  management
                                     techniques   are  available for  opti-
                                     mizing degradation kinetics.

                                          Intermediate products formed in
                                     the  degradation of PAH compounds
                                     in soil systems, as  a class, proceed
                                     through  a  cycle of  generation  and
                                     degradation  which   complements  the
                                     parent  compound  cycle  in soil.
                                     Intermediate  degradation  products
                                     are generally more polar than parent
                                     PAH compounds (8), and thus are more
                                     readily  transported   (leached)
                                     through soil systems than parent PAH
                                     compounds.    Optimization of treat-
                                     ment  of PAH  compounds,  therefore,
                                                   degradation in a corn-
Table 2.   Effect of manure  and pH  amendments on PAH
          pi ex waste incorporated  into soil.

                                   Half-Life in Waste:Soil Mixture (days)
PAH Compound
Acenaphthylene
Acenaphthene
Fluorene
Phenanthrene
Anthracene
Fluoranthene
Pyrene
Benz(a)anthracene
Chrysene
Benzo(b)f luoranthene
Benzo ( k ) f 1 uorant hene
Benzo(a)pyrene
Benzo (ghi)perylene
Di benz( a, h) anthracene
Indeno(l,2,3-cd)pyrene
Without amendments
78
96
64
69
28
104
73
123
70
85
143
91
74
179
57
With amendments
14
45
39
23
17
29
27
52
42
65
74
69
42
70
42
                                   69

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Table 3.   Effect  of  soil  moisture
          on  PAH degradation (re-
          sults  presented  as  half-
          life in days).

Moisture
20-40%
field
capacity
60-80%
field
capacity
Anthra-
cene
43


37


Phenan-
threne
61


54


Fluroan-
thene
559


231


also requires  optimizing treatment
of PAH  degradation products.

     The Ames  assay  was used  to
determine the mutagenic potential of
PAH  degradation  products  in soil.
Figure 2   presents  results  of
laboratory  studies with the  PAH
compound  B(a)P  and  soil  metabolites
of B(a)P.  It is obvious  from Figure
2 that the  mutagenicity of polar
degradation  products  increases  and
then decreases with incubation time,
or treatment time, in soil.   Results
also indicate  that the  mutagenic
potential  of degradation products,
as  a class  of polar  metabolites,
is  much less  than  the parent  com-
pound.   A  detoxication  pathway  is
indicated  for  soil biodegradation
(Figure 2).

     The Ames assay was also  used to
evaluate  potential   mutagenicity
of  leachates  produced in glass
column leaching  experiments  con-
ducted  with  complex wastes contain-
ing PAH compounds.  Results for the
Ames  testing  of  leachates  are
summarized in Table 4.   Results for
the control  leachate collected  from
columns  without  waste addition
demonstrate  a  negative response
Table 4.   Results   for  Ames  assay
          testing of leachates. (Re-
          sults  expressed  in terms
          of  mutagenic ratio.  Neg-
          ative  response   indicated
          by mutagenic ratio  of less
          than 2.0).
Treat-
ment
Control a
Waste: Soil
Mixture
Treatment Time
0 61
1.50 1.75
1.25 4.05
(days)
91
1.50
1.85
                                     aControl  indicates
                                     waste  addition).
                    soil  only (no
(mutagenic  ratio  is  less than 2.0),
and therefore the leach ate from soil
with  no complex waste addition
is not mutagenic.

     Results  for  leachate generated
at  the  beginning  of  the study
for  the wastersoil  mixture  also
demonstrated  no  mutagenicity.  This
result is expected since the parent
PAH  compounds  are  not   highly
soluble  in  water.   PAH compounds
also  demonstrate high partitioning
into  soil  organic matter  (8),  and
the  soil  used  in  the  laboratory
study had a relatively high  organic
carbon content of 1.0 percent.
Also  very  few  PAH  degradation
products would  be expected   immedi-
ately after waste incorporation into
soil.

     Results  for  leachate generated
at  61  and 91  days  after  initial
waste  incorporation   into soil
indicate  increased  mutagenicity
(intoxication) followed by decreased
mutagenicity  (detoxication) compared
with the initial  waste incorporated
soil.    Thus  polar metabolites
resulting  from  PAH  degradation  in
                                  70

-------
soil  are  mutagenic  and  may  be
transported  through  soil  under
saturated conditions.   More  research
is  required  to  characterize  the
mobility and toxicity of biodegrada-
tion products  of  PAH compounds  in
soil systems.


ACKNOWLEDGMENTS

     The  analytical  and  bioassay
services  and  assistance  received
from North  Carolina  State Univer-
sity, Department  of  Biological  and
Agricultural   Engineering,   Research
Triangle   Institute,  Chemistry
and Life Sciences Division,  and Utah
State  University,  Utah  Water
Research Laboratory are appreciated.


REFERENCES

1.   Barr,   A.J.,  J.H.  Goodnight,
     J.P.  Sail,  and J.T.  Helwig,
     1976, A User's Guide to SAS-76,
     SAS  Institute,   Inc.,   Raleigh,
     NC, 329 p.

2.   Herbes, S.E.,  G.R.  Southworth,
     and  C.W.  Gehrs,  1976, Organic
     Constituents in  Aqueous Coal
     Conversion Effluents:   Environ-
     mental  Consequences   and  Re-
     search  Priorities,  In:   Trace
     Substances  in  Environmental
     Health-X.   A Symposium.   D.D.
     Hemphill  (ed.), Univ.  Missouri,
     Columbia, MO.

3.   Hoagland, D.R., and D.I.  Arnon,
     1950,  The Water-Culture  Method
     for Growing Plants   Without
     Soil,  Univ.  of  California
     Agricultural Experiment Station
     Circular  No. 347, 32 p.
Longbottom,  J.E.,  and J.J.
Lichtenberg, 1982, Test Methods
for Organic  Chemical  Analysis
of  Municipal   and  Industrial
Wastewater,  Method  610:  Poly-
nuclear  Aromatic  Hydrocarbons,
EPA-600/4-82-057,  U.S. EPA
Environmental  Monitoring and
Support  Laboratory,  Cincinnati,
OH.

Mahmood,  R.J., and  R.C.  Sims,
1985,  Modeling the  Behavior of
Polynuclear  Aromatic  Compounds
in Soil  Systems,  In:   Proceed-
ings,  1985 National  Conference
on  Environmental  Engineering,
ASCE  Specialty Conference,
June,  Boston,  MA.

Maron,  D.M.,   and  B.N.  Ames,
1983,  Revised  Methods  for the
Salmonella  Mutagenicity  Test,
Mutation Res.,  Vol.  113, pp.
173-215.

Sims,  R.C., 1982, Land  Treat-
ment of  Polynuclear Aromatic
Compounds,  Ph.D.  Dissertation,
Dept.   Biol.  Agric.  Eng.,
North Carolina  State  Univ.,
Raleigh,  NC, 387 p.

Sims,  R.C.,  and M.R.  Overcash,
1983,  Fate   of  Polynuclear
Aromatic Compounds  (PNAs) in
Soil-Plant  Systems,  Residue
Reviews,  Vol. 88,  pp.  1-68.

Umfleet, D.A.,  1985,  In Situ
Treatment of Polynuclear
Aromatic Compounds  Present in
Industrial Wastes, M.S. Thesis,
Dept.  Civil Environ.  Eng., Utah
State  Univ., Logan,  UT.
                                   Disclaimer

   The work described in this paper was  not funded by the U.S. Environmental
   Protection Agency.  The contents do not necessarily reflect the views of the
   Agency and no official endorsement should be inferred.
                                 71

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               A  NEW VENTURE IN INTERNATIONAL WASTE MANAGEMENT

                                John Bui tin
                            John A. Bui tin Ltd.
                            Manchester, England
                                    and
                             Brown Bui tin Ltd.
                              Virginia, U.S.A.
                                  ABSTRACT

    The paper  discusses developments  in  waste management possibilities,
technologies,  services and institutions that are  opened  up by international
transfer.   It is  demonstrated  that,   under  careful  management,   the
international  transfer either  of wastes or experience can benefit the United
States both in the short and  long term in its continuing  search for radically
improved hazardous waste management.
                                 Disclaimer

                    The work described in this paper was
                    not funded by the U.S. Environmental
                    Protection Agency.  The contents do
                    not necessarily reflect the views of
                    the Agency and no official endorse-
                    ment  should be inferred.
                                      72

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    THE UNITED STATES/MEXICO ENVIRONMENTAL AGREEMENT OF 1983
        BI-NATIONAL HAZARDOUS MATERIALS & WASTE MANAGMENT

                          Lauren Volpini
          United States Environmental Protection Agency
                    San Francisco, California
                             ABSTRACT

    The Agreement between the United States of America and the
United Mexican States on Cooperation Cor the Protection and
Improvement of the Environment in the Border Area was signed by
Presidents Reagan and de la Madrid in La Paz, Mexico on August
14, 1983.  It reaffirms, through political will, the great im-
portance each nation places on a healthful common environment
and demonstrates a commitment to cooperatively solve environ-
mental problems of mutual concern in the border area.  The
Agreement also requires that each nation facilitate the pre-
vention, reduction, and elimination of sources of pollution
within its purview which may affect the neighboring country.

    The US Environmental Protection Agency (EPA) and Mexico's
Subsecretariat de Desarrollo Urbano y Ecologia (SEDUE) were
designated as National Coordinators to implement the Agreement,
The National Coordinators established three bi-national technical
teams - one focusing on air pollution, one on water pollution
and one which is the subject of this paper, the US/Mexican
Hazardous Materials and Waste Management Workgroup.  The Work-
group was charged with identifying and addressing actual or po-
tential hazardous material and waste management problems of
mutual concern to the border area.

    The Workgroup identified 7 areas for priority action and
developed specific short and long term objectives to address each
problem area.  These areas are:  the transboundary movement of
hazardous materials, joint inland contingency response planning,
training, agricultural chemicals, in-bond companies, municipal
and hazardous waste facilities, and ocean incineration.

    Workgroup efforts to prevent, eliminate and reduce border
pollution problems involving hazardous materials and waste can
best be accomplished when primary bi-national relations are
harmonious, where cooperation and responsiveness distiguish local
as well as federal interactions and where there is a sufficient
commitment of staff and resources.  The cooperation of the gen-
erators, transporters and disposers of hazardous materials and
waste through compliance with EPA and SEDUE regulations and
policies is essential.

INTRODUCTION AND PURPOSE           dents Reagan and de la Madrid
                                   signed the "Agreement between
    On August 14, 1983 Presi-      the United States of America


                               73

-------
         *
       V/ US/MEXICAN BORDER
     AREA OF ENVIRONMENTAL CONCERN
CAUFORNIA
                              NUEVO LEON


                                  TAMAULIPAS .

-------
and the United Mexican States
for the Protection and Improve-
ment of the Environment in the
Border Area." The Agreement
established a 200 km wide zone
of mutual interest along the
border, covered all environ-
mental media and designated
the United States Environmen-
tal Protection Agency (EPA)
and the United Mexican States'
Subsecretatiat de Desarollo
Urbano y Ecologia (SEDUE)  as
the National Coordinators
to implement the Agreement.
On March 8-9, 1984 EPA and
SEDUE delegates convened in
Tijuana, Mexico and San Diego,
CA to discuss common interests
and concerns in the areas of
air, water, and soil pollution
(issues involving toxic sub-
stances and hazardous waste
management were initially
included within the category
of "soil pollution").  To
initiate cooperative measures
within the framework of the
Agreement, the delegations
established three bi-national
technical workgroups: air,
water, and soil.

    This paper chronicles the
developments of the technical
workgroup on soil now called
the US/Mexican Hazardous Ma-
terials and Waste Managment
Workgroup, and discusses the
current status and future
expectations of US/Mexican
hazardous materials and waste
management.

    It is hoped that the sub-
ject information will inform
those parties in the public,
private and academic sectors
with interests particular to
OS/Mexican hazardous materials
and waste management.
US/MEXICAN BORDER ENVIRONMENT

    The US/Mexican border is
approximately 1900 miles long,
of which 1230 miles is largely
the Rio Grande River.  The
Border begins and ends with
the Pacific Ocean on the west
and the Gulf of Mexico on the
East.  Several surface water-
ways transect the border: the
Tijuana, Alamo, New, Colorado,
Santa Cruz, and San Pedro
Rivers.  The Salton Sea,
Laguna Salada,Greenbrush Draw,
Nogales Wash and the Gulf of
California are significant
water basin features either
partially or fully located
within the border area.

    Land and water uses in the
border area include some of
the most productive agricult-
ural and ranching lands in the
US and Mexico, commerical
fishing, mining and minerals
processing, nuclear power gen-
eration and increasing indust-
rialization and associated
urbanization.

    Documented environmental
issues in the border area
include air quality, water
quantity and quality, marine
pollution, soil contamination,
and wildlife habitat destruc-
tion.

WORKGROUP ORGANIZATION

    There are four states on
the US side of the border:
two in EPA Region 9 - Cali-
fornia and Arizona and, two
in EPA Region 6 New Mexico
and Texas.

    The US Workgroup delega-
tion chaired by the Director
of the Toxics & Waste Manage-
ment Division, EPA Region 9
                               75

-------
and consists of  four EPA
officials from Regions  6 and
9 and the Office of Interna-
tional Activities  (OIA)
and one US Embassy official.

    There are six states on
the Mexican side of the border:
Baja California, Sonora, Chi-
huahua, Nuevo Leon, and Tamau-
lipas.  The Mexican Workgroup
delegation, chaired by  the
SEDUE Director of the Preven-
tion and Control of Environ-
mental Contamination, consists
of four SEDUE officials and
is based in Mexico City.

WORKGROUP GOALS AND OBJECTIVES

    To best clarify the problem
field of the Workgroup  - haz-
ardous materials and waste -
the Workgroup first proposed
that its name be changed to
the Hazardous Materials and
Waste Management Workgroup.
The original name, the Soils
Workgroup, was determined to
be inappropriate because it
implied that the Group was
concerned with one of the
pathways of contamination
(soil) instead of proper
management of the substances
of contamination.

    The longterm goal of the
Work group is to identify and
address as appropriate, actual
or potential hazardous mater-
ial and waste management prob-
lems of mutual concern along
the US/Mexican border.

    7 problem areas of mutual
concern were identified as
requiring priority action
and subdivided into primary
and secondary issues:
Primary Priority Issues

The Transboundary Movement of
  Hazardous Materials

Joint Inland Contingency
  Planning

Training  (Note:  To high-
light the importance of this
primary priority area, a
specific objective of the
Workgroup's long term goal
is the professional develop-
ment of individuals to enhance
the capability to address
hazardous material and waste
management issues.)

Secondary Prority Issues

Agricultural Chemicals

In-Bond Companies

Municipal and Hazardous Waste
  Facilities

Ocean Incineration
THE TRANSBOUNDARY MOVEMENT OF
    HAZARDOUS MATERIALS

    Current US and Mexican
efforts have been inadequate
to prevent the indiscriminate
and uncontrolled transborder
movement of hazardous mater-
ials.

    US legislation that
addresses hazardous waste
exports is contained within
Section 245 of the Resource
Conservation and Recovery Act
(RCRA) ammended in November,
1984.

    Currently, even those ex-
porters of "RCRA regulated"
hazardous waste are only re-
quired to notify* OIA with 30
                              76

-------
days anticipation of their
first export of the year, so
that OIA may notify the recip-
ient country's government.  Ap-
proval from the foreign gov-
ernment is not requested.  How-
ever, commencing in November,
1986, RCRA will require that no
person may export hazardous
unless:  1) they have filed a
notification with EPA's OIA
and, 2) the receiving country
has agreed in writing to accept
the waste and, 3) a copy of the
acceptance is attached tothe
manifest.

Additionally, an annual report**
must be filed with OIA for each
preceeding calendar year's acti-
vities.

    RCRA does not fully regu-
late exports of material claimed
to be "product" or for reuse,
nor of low volume waste ship-
ments.  If the exporters and
transporters characterize the
material in ways that exempt
the shipment from RCRA regula-
tion, appropriate communication
of the transboundary movement
may not be achieved.

Workgroup objectives for this
priority issue are:  Short
Term  1) to develop a system
to communicate information
concerning transborder move-
ments, 2) establish a direct
EPA to SEDUE Regional Hot Line
to communicate information on
known and potential shipments
and; Long term   1) to develop
a mechanism to implement the
new RCRA legislation through a
Bi-national Agreement, 2) to
investigate "sham recycling",
and 3) to assess the need for
statuatory/regulatory changes
based upon ongoing Workgroup
efforts.
    Specific shore term Work-
group activities underway to
address this priority issue
include sharing all available
information on hazardous ma-
teria imports, developing an
ongoing training program for
US and Mexican Custom Agencies
in the area of transborder
hazardous material movement
and, increasing surveil lance
to identify potential illegal
imports and exports.
*  The exporter(generator)
must file a notification only
once per calendar year with
an estimate of the waste type
and quantity, the frequency,
dates and ports of entry,
method of transportation,
treatment, storage, and
disposal, and the name/loca-
tion of the foreign consignee.

** The annual report must sum-
marize the types, quantities,
frequencies, and ultimate des-
tination of all hazardous
waste exported during the
previous year.
JOINT INLAND CONTINGENCY
  PLANNING

    In July, 1980, an oil
spill response agreement,
titled, the "Agreement of
Coordination Between the
United States of America and
the United Mexican States
Regarding Pollution of the
Marine Environment by Dis-
charges of Hydrocarbons and
Other Hazardous Substances,"
was signed.

    A Contingency Plan to be
iEiplemented by the US Coast
Guard and the Mexican Navy was
                              77

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developed as a series of
annexes to the Agreement and
outlines cooperative measures
and proceedures to be taken
in the event of a discharge
to the marine environment.
This Marine Plan served as the
model for an EPA Headquarters
drafted document which
was submitted to SEDUE for
approval as an Annex to the
OS/Mexican Environmental
Agreement.

In May, 1985, the Workgroup
convened in San Francisco to
discuss the still unsigned
Plan as a Workgroup agenda
item.  Through technical
discussions and negotiations
and increasing familiarity
with eachother's needs,
abilities, limitations and
potentials, the Workgroup
revised the Plan and jointly
endorsed it for recommendation
to the National Coordinators.
This Agreement and its set of
appendices is called "The
Agreement of Cooperation
Between the United States of
American and the United Mexican
States Regarding Pollution of
the Environment Along the In-
land International Boundary
by Discharges of Hazardous
Substances," or The Plan.

Plan Objectives

    The primary intent of the
Plan is to provide for a
coordinated response capabil-
ity at the scene of a dis-
charge of hazardous substances
that pose or may pose a threat
to the public health, welfare
or the environment.  Apart
from joint response authority,
the Plan commits each country
to provide contingency
planning within its own
boundary.*
The Plan calls for a Joint
Response Team (JRT) to be
headed by US and Mexican
Co-Chairmen.  As required by
the Plan and via the JRT,
bi-national agreement will be
necessary to initiate a joint
response, to determine what
response measures will be
taken and when to terminate
the response.

The Plan outlines the desig-
nation, functions and re-
sponsibilities of the JRT
and primary response officials
such as the On-Scene C9ordin-
ator (OSC) and the Advisory
Liaison Coordinator (ALC).

Workgroup objectives for this
priority issue are: Short Term
1) Signature of the Plan and,
2) Development of an imple-
mentation plan with a schedule
and list of participants, and;
Long Term 1) Full implementa-
tion of the Plan and, 2) A
joint emergency response exer-
cise.

    Specific short term Work-
group activities underway to
address this priority issue
include developing local re-
sponse plans involving
sister cities.

    The Workgroup will facili-
tate a pilot program for the
city pair of Mexicali/Calexico.

The pilot will help develop
model procedures for noti-
fication and response.

    Under its responsibility to
implement the National Con-
tingency Plan (NCP), EPA
recognized that area specific
border contingency planning
was needed to complement
existing contingency plans.
                              78

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Prior to the initial Workgroup
meeting, EPA contacted local,
state, county, regional, fed-
eral and academic parties with
interests, responsibilities,
experience and expertise
specific to hazardous material
issues in the border area.
A resultant document outlined
border agency authorities,
concerns (both known and
potential) and abilities to
participate in Workgroup and/
or response activities.  Re-
gional Border Task Forces were
then created to facilitate in-
formation flow and response
cababilities.
* The US' National Contingency
Plan (NCP) (with Regional and
Local subsets) provides for
response to emergencies caused
by oil spills and releases of
hazardous substances to all
media (land, air, surface
water and ground water).
TRAINING

    Recognizing that resolving
environmental problems re-
quires educating and properly
equiping those persons who
will participate in accomp-
lishing Workgroup objectives,
the issue of training is of
highest priority.

    Workgroup objectives for
this issue are:  Short Term
1)  Comprehensive assessment of
training needs and; Long Term
1)  Development and implementa-
tion of a permanent and formal
training program.

    Specific short term Work-
group activities planned to
address this priority include:
1)  EPA will inform SEDUE of
response activity to be held
in the border area so that
SEDUE may send site observers;
2) SEDUE is expected to pro-
vide EPA with an assessment
of their training needs;
3) EPA will provide SEDUE
with available training
options; 4) The Workgroup will
establish workshops and ex-
plore bi-lateral personnel
assignments to address speci-
fic training needs.

SECONDARY PRIORITY ISSUES

Agricultural Chemicals
In-Bond Companies
Municipal and Hazardous Waste
Facilities
Ocean Incineration

    It was agreed that the
Workgroup did not possess
enough information on these
issues or their environmental/
public health impacts to
identify specific implementa-
tion actions to address them.
Therefore, these secondary
issues of mutual concern
will be elevated to primary
issues if additional data
and problem assessment indi-
cate the need to do so.

Workgroup objectives for these
issues then, focus on the gen-
eration and communication of
information: 1) Identification
and exchange of environmental
data; 2) Exchange of technical
information and; 3) Notifica-
tion of any significant
actions or events.

Workgroup activities inspired
by the Muncipal and Hazardous
Activities Issue include:
1) EPA has provided SEDUE with
hazardous waste land disposal
technical manuals and, 2) EPA
held technical briefings and
                              79

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hosted a tour of several OS
hazardous waste land disposal
sites for a delegation of
SEDUE and Mexican industry
officials during May, 1985.
CONCLUSION

*   There are dramatic environ-
mental and health consequences
possible due to the improper
handling of hazardous materials.

0   The Workgroup is in its be-
ginning stages of problem
assessment.

*   There is insufficient in-
formation on the extent of
US/Mexican hazardous materials
and waste problems in the
border area.

*   In order to meet present
and future requirements for
effective and safe transborder
hazardous material and waste
management will depend upon
the development of:

-  An effective system of iden-
tification and evaluation of
hazardous materials.

-  Positive efforts in the
fields of research and science,
industry and appropriate
technology, cross cultural
implementation, international
peace and harmony, legislative
and diplomatic mechanisms,
cooperative enforcement, and
the generation and appropriate
application of reliable
information.

ACKNOWLEDGEMENTS

    The development and pro-
gress of US/Mexican hazardous
materials and waste management
has been made possible only
 through the great personal
 commitment and efforts of ray
 fellow Workgroup members:

 Harry Seraydarian, Director-
 Toxics and Waste Management
 Division  (EPA Region  9)  and
 Workgroup Co-Chair, Allyn
 Davis, Director-Air & Waste
 Management Division (EPA
 Region 6), Terry Brubaker,
 Chief-Emergency Response
 (EPA Region 9), Jeff  Lutz,
 Science Officer-US Embassy,
 Mexico City, Enrique
 Acosta, Director-Prevention
 and Control of Environmental
 Pollution (SEDUE) and Work-
 group Co-Chair, Francisco
 Zepeda, Director-Solid Waste
 & Soil Pollution, Miguel
 Herrera, Deputy Director-Solid
 Waste & Soil Pollution (SEDUE)
 and, Pederico Wilkens, Advisor
 to the Secretary (SEDUE).

 TheAuthor

     Lauren Volpini has been
 with the US Environmental Pro-
 tection Agency, Region 9, San
 Francisco, CA since 1980.
 She specializes in oil and
 hazardous materials prevention
 and emergency response and
 also serves as the Interna-
 tional Activities Coordinator
 for the Toxics and Waste
 Management Division.
            Disclaimer

This paper has been reviewed in
accordance with the U.S. Environ-
mental Protection Agency peer and
administrative review policies and
approved for presentation and publi-
cation.
                               80

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                MANAGEMENT OF HAZARDOUS WASTES  GENERATED BY
                        CHEMICAL INDUSTRIES IN  INDIA

                     D. K. Biswas* R. R. Khair and  D.  De
                         Department of Environment
                             New Delhi - 110011
                                  ABSTRACT

    Hazardous  Waste Management  has  so far received perfunctory attention in
India.  Quantitative  information  on a countrywide basis concerning the nature
and quantities of hazardous  wastes from chemical industries is not available.
A sample survey, commissioned by  the  Department of Environment,  on selected
chemical industries has revealed that as much as  22  percent of solid wastes
are hazardous  in  nature.  These are usually disposed in nearby, lowlying areas
without proper treatment and  protection  measures.   India's  current  laws and
regulations do not adequately provide  for safe handling and secured disposal
of hazardous substances.  An appropriate Act arid institutional  mechanism must
be instituted  to regulate disposal of  these substances.  Some steps that have
recently  been  taken  include  industrial location  policy,  procedure  of
environmental  clearance for project approval* formulation of industry-specific
standards,  and  fiscal incentives for pollution control.  An  integrated
approach  in terms  of  policy and regulatory and  promotional  measures is
recommended  for coping  with  the  mounting  problems of  hazardous  waste
management.
                                  Disclaimer

                    The work described in this paper was
                    not funded by  the U.S. Environmental
                    Protection Agency.  The contents do
                    not necessarily reflect the views of
                    the Agency and no official endorse-
                    ment should be inferred.
                                      81

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       THE  BAVARIAN SYSTEM FOR SPECIAL WASTE MANAGEMENT -
          15 YEARS  EXPERIENCE IN COLLECTION,  TREATMENT,
                       DISPOSAL AND CONTROL
                         Franz  Defregger
                   Bavarian  State  Ministry for
            Regional  Developement and Environmental
                         Affairs,  Munich
                   Federal Republic of Germany
                             ABSTRACT

Bavaria with  an  area  of  70  000  sq.kms and nearly ,11 millions
inhabitants was  the first State in the Federal Republic of
Germany (FRG) to address central  responsibility for the disposal
of special wastes. In the middle  part of the State, a regional
special association was  formed  in 1966 to operate waste disposal
sites  ("Zweckverband  Sondermullplatze Mittelfranken",  abbreviated
as "ZVSMM").  Soon thereafter the  Bavarian Corporation for Dis-
posal  of Special Wastes, Ltd.  ("Gesellschaft zur Beseitigung von
Sondermull in Bayern  mbH",  abbreviated usually as "GSB") was
established in 1970 to provide  and operate facilities necessary
for the proper management of industrial wastes. The GSB operates
a network of  regional collecting  points and several central dis-
posal  facilities. At  present in Bavaria 10 regional collecting
points and 3  central  special-waste disposal facilities are in
operation, in which nearly  350  000 tons special waste are treated
and disposed per year.
The special waste is  temporarily  deposited at the collecting
points, where it is classified  for bulk transport to the disposal
plants. In addition,  the collecting points are responsible for
pretreating waste like neutralisation,  dewatering,  emulsion
separation and sludge thickening.  .

The central disposal  facilities in Ebenhausen (near Ingolstadt)
and Schwabach (near Nurnberg) are  one of the most advanced of its
kind in the FRG  and consists central laboratories,  chemical-
physical treatment, incineration  (rotary kilns) and secure land-
fill sites. The  Landfill Gallenbach,  in operation since 1975 will
also discussed in this paper in view of collection, analysis and
treatment of  leachate. A research  program had been undertaken for
treating the  leachate in a  distillation plant.

Since  1972, GSB  runs  also a recycling plant for contaminated
solvents with a  capacity of 4000  tons per year.


                               82

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INTRODUCTION

The FRG was one of the first
European countries to give
serious attention to the
problem of hazardous waste. It
passed the Waste Disposal Act
in 1972. The Federal Govern-
ment has some responsibility
for manging hazardous waste.
There is national legislation
and international issues are a
federal concern. However, the
Landers or States have the
legal responsibility for
implementing and enforcing the
legislation. At the national
level, the German Ministry of
Interior published a list of
abbout 570 types of waste in
1975 and two years later 38
waste streams were identified
as special or hazardous. These
substances are defined by
category (e.g., gas scrubber
sludges), techology (e.g.,
electroplating), general grou-
ping  (pesticides) or specific
proscription. About three to
four million tons of hazardous
waste are generated each year
in the FRG. About 50 percent
is disposed of in secure land-
fill sites, 35 percent is
treated by chemo-physical
means and the final 15 percent
is disposed off by incinera-
tion .

Within the system of waste
treatment in the State of
Bavaria there has developed an
elaborate charge system during
its 15 years of operation.

Wastes usually are delivered
to the ten collection stations
situated around Bavaria (see
Figure 1) by the waste genera-
tors. Preliminary treatment of
some waste takes place at these
collection stations and then
the waste is transported by
private carriers to the three
major disposal sites  in the
state. There the wastes are
treated in a manner designed to
remove the hazard  from wastes
by an overall cost minimizing
technology.

          APPROACH

Company for Disposalof Special
Waste ltd. (GSB)

With the exception of the
treatment plant of Schwabach
which is run by a municipal co-
operative, called  "Zweokverband
Sondermiillplatze Mittelfranken"
(ZVSMM), all the other facili-
ties and collecting stations
are run by the "Gesellschaft
zur Beseitigung von Sondermiill
in Bayern mbH" (Company for
Disposal of Special Waste in
Bavaria ltd.), for short "GSB",
which was established as a
country-wide organization in
1970. It's stock fund amounts
arose from 1 million  in 1970 to
21 millions DM today. Share-
holders of the company are the
Bavarian State (78 %), 3 mu-
nicipal organizations (8 %) and
76 industrial firms (14 %). The
task of the GSB is to provide
and operate facilities neces-
sary for the treatment of spe-
cial waste and the recovery of
raw materials from special
waste all over Bavaria. The
activity of the company is
conducted on a not profit-base
but being a private company the
GSB has to search permanently
new ways to treat the hazardous
waste in order to get a proper
                               83

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                                                  Figure  1
                                     STATE OF BAVARIA • WEST GERMANY
                                    SPECIAL WASTE MANAGEMENT SYSTIM
                                                      Situation 1985
                                                        Incirwnrtlbn Ndlltl-w

                                                        TfWEtmfrnt ftEilltiiN
                                                     IB OuillfMiMpwItory

                                                     f—j Contains (Mint

                                                     ^^ Rvoowy plant
10 collecting points
 3 central  treatment and  disposal facilities
   (incineration,  chemo-physical  treatment,  landfill)
 1 recovery plant  for contaminated solvents
                             84

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disposal or a recovery of raw
materials from this waste.

Since GSB waste disposal is
not profit oriented and since
the board of directors, which
represents the shareholders,
must authorize the disposal
costs, the conditions have
been created under which
industrial and manufacturing
establishments deliver their
wastes for orderly treatment
in accordance with the law but
without having to be forces
(courtorders, fines). The
publicly held share of over
75 % in the company guarantees
optimal environmental protec-
tion being the first priority
during construction and opera-
tion of all facilities and
also in the choice of methods
used in waste disposal. The
GSB has served as the model
for similar corporate entities
with identical tasks in other
States of the FRG.

Collection and Transportation

The collecting points are
fairly uniform in the service
and in their equipment (see
Figure 1). They provide an
intermediate holding function
and have equipment, which is
fairly simple to run. They
pretreat as much waste as
possible to cut down the
volume. They have a waste
water treatment plant, in
which the separation of the
usually large volums of oil-
water mixtures into water and
solids takes place. The
treated waste-water is dis-
charged locally. The waste
volume is cut back to 10 % of
the original. Where necessary,
facilities  for  neutralizing  and
sludge thickening  are  in  place.
All gathering points have an
administration  building and
testlab, vehicle scales and  an
area for oily soil  and con-
tainers to  receive  and provide
intermediate storage for  in-
dustrial sludges of all types.

Ebenhausen  central  treatment
facility

The biggest and most modern  of
the three bavarian  hazardous
waste facilities is the faci-
lity Ebenhausen which  started
up 1976 on  a 4  hectare site  in
Ebenhausen  near Ingolstadt and
a 17 hectare landfill  in  Gal-
lenbach 25 miles away  (no suit-
able site was available next to
the treatment plant Ebenhau-
sen). The Ebenhausen plant
comprises a laboratory, a
chemical-physical treatment
plant for organic and  inorganic
substances  (oil-emulsions, used
acids, alkalies, galvanizing
and other inorganic sludges,
solutions containing chrome,
cyanides, nitrites  etc.),  a
water purification  plant,  as
well as Germany's largest waste
incineration plant  with a
capacity of 100 times  10  to  the
sixth power btu/h or 70 000
tons (see Figure 2).

Incineration

The incineration plant, able to
process 70  000  tons/yr waste,
has two parallel rotary kilns
for solid and pasty  wastes  and a
common burner-chamber  with a
set of six burners  for liquid
wastes. The heat of the off-
gases fr^m the  after-burners is
utilized in a steam boiler
                               85

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 where  the off-gases are colled
 down f^oin 1  000 centigrades to
 about  270 centigrades,  thereby
 generating up to 30 tons
 steam/h  out  of which 22 tons/h
 are consumed in a 1,530 kw
 steam  turbine while the re-
 mainder  is condensed in an air
 condenser; this electric
 energy not only the incinera-
 tion plants  entire power re-
 quirement but actually  leaves
 an excess supply for the
 public grid.  The steam  from
 the turbine  (three atmospheres
 pressure)  is  utilized for
 heating  the  building and for
 process  heat  in the chemical-
 physical treatment plant.

 Off-gas  purification comprises
 an electrical  precipitator for
 dust retention and a two-stage
 venturi-type  scrubber which
 removes  HCL and HP almost  com-
 pletely  while  retention of SO
 is 70 pc.  is  enhanced by
 flocculants.  As regards air-
 borne  emissions and scrubbing
 water pollutants,  this  indu-
 strial incinerator has  been
 reviewed  several  times.  From
 simultaneously performed
measurements of HC1,  SO ,  HF
and dust  in raw gas and clean
gas,  the  following fluctuation
margins  for routine operation
can be derived:
Pollutant Raw gas

         mlg/m3
Clean gas limit

mg/m3
HC1
SO
£.
HF
dust
1000-4000
450-2100

62-260
1000-2000
22-90
40-300

1-3
10-20
100
400

5
50
           Table 1
    Emmissionrates of the
   Ebenhausen incineration
Chemical-physical treatment

In the physicochemical treat-
ment plant the materials are
enloaded in one of the differ-
ent 30 m3 receiving tanks
depending on the results of the
laboratory tests. These tanks
lead into several storage and
finally, there are followed by
the individual treatment faci-
lities of mixing and dosing
units.

Liquids with inorganic and
organic contaminants are
treated in the following ways

-  neutralizing
-  detoxification
   o  oxidation cyanid
   o  oxidation nitrite
   o  reduction chromate
-  Separation of solid sub-
   stances (decanter)
-  Chemical seperation of
   emulsions
-  Flocculation of oil
-  Precipitation of metal
   salts
-  Flocculation, using poly-
   electrolytes
-  Separation of sludge and
   water phase  (in drum fil-
   ters)
-  Subsequent treatment,
   employing oxidation and
   reduction processes

The residues of the treatment
processes  (dewatered, neutral-
ized sludges, fly-ash, slag)
and other  solid wastes are
deposited  at the two landfill
sites in Schwabach and Gallen-
bach by special security
conditions. A third landfill
site, located in Raindorf goes
in operation in June, 1985, and
will be the most modern site
                               86

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                       Sent* uujc
                                            n Central Tr»jim#flt Pt*«t
Figure  2_;_  Ebenhausen Central Treatment Plant
 Figure 3;   Gallenbach  Landfill  Site
                               87

-------
in Europe  (capacity:
800 000 m3, basic-clay-cover:
2,0 m, owner:  ZVSMM).  While
the landfill site  of  Schwabach
is located together with  the
treatment  facilities,  the
Gallenbach site  is dislocated
(over 40 km) from  the  Ebenhau-
sen treatment  facilities  in
view of liydrogeological condi-
tions .

Gallenbach Landfill

The Gallenbach Landfill is in
operation  since  1975 and  com-
prises the following installa-
tions: (see Figure 3)

—  Operational building with
   amenity rooms of various
   types for the personal.
-  Laboratory  for  sampling of
   the substances  delivered.
-  Vehicle weigli bridge.
-  Vehicle and instrument
   sliop.
-  Control systems (drainage,
   retaining basins) for  hold-
   ing and treating the storm
   water and leachate.

The site is operated by the
'area method1 of landfilling
on a 100 cm thick, pre-con-
structed clay pad with a  re-
ported permeability of 10 m/s.
Watersoluble solid wastes con-
taining heavy metals are
desposited in drums and
covered with concrete  to
reduce the contamination  in
the leachate.
In addition to daily cover, a
plastic membrane is inter-
mittently placed over  com-
pleted lifts to  reduce infil-
tration. A hand operated
vibrator is also utilized to
compact daily cover in an
effort to reduce the volume of
leachate generated. The quan-
tity of leachate could be re-
duced in the last years through
several measures like high
compaction, applying layers of
impermeable material, landfil-
ling in small sections from
80 % to nearly 40 %.

Collection, Characteristics and
Treatment of Leachate

Leachate is collected by a
series of underdrains, located
in the clay pad. Leachate is
then channeled to a plasic
lined (3 mm) detention pond
from where it is trucked to
Ebenhausen-Plant for treatment.
Approximately 10,000 tonnes per
year of leachate is hauled
40 km to the Ebenhausen com-
plex. Average leachate charac-
teristics are identified in
Table 2 .
                               88

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Parameters
pH
BOD
COD
TOG
Cr
Cu
Cn
Ni
Zn
Cd
Fe
Sn
Pb
Phenole
Choloride
Sulphate
Amonia
1977
7,0
2720
3000
1600
0,4
0,3
-
4,1
2,3
0,2
12
2,3
0,6
2,1
15000
21
118
1978
7,4
3000
3500
1900
0,7
0,3
-
5,2
0,5
0,1
4
8
1,0
7,3
26000
3400
433
1979
7,2
4000
9000
4000
0,5
0,4
0,1
3,6
0,6
0,2
4
44
1,2
1,0
37000
8300
900
1980
7,4
4650
12000
3400
0,2
0,3
0,1
4,4
0,4
0,2
2,1
34
1,1
10
40000
3300
900
1981
7,4
4370
—
3700
1,0
0,4
0,1
4,1
0,7
0,8
2,7
3,1
6,4
14
51000
4100
920
1982
7,5
3500
-
3100
0,5
0,3
0,1
4,1
0,6
0,2
3,5
3
1,8
8,6
44000
1700
1000
1983
7,6
2500
3600
1700
0,3
0,1
0,1
2,5
0,7
0,1
1,7
2
0,6
12
28000
3800
790
Table 2 ; Average leachate concentrations  (mg/1)  in  Gallenbach
         1977-1983
The leachate is characterized
by high organic (BOD, GOD,
TOC) and inorganic concentra-
tions, in particular salt
contents between 15 g/1 and
50 g/1 and ammonia between
100 mg/1 and 1000 mg/1 also
some heavy metals like zinn
with 40 mg/1.

From nearly 84 000 m3 leach-
ate, generated 1976-1982, it
was estimated that over 3260
metric tons were produced as
salt and about 2750 kg heavy
metal ions were diluted. In
relation of the landfilled
quantity of solid wastes
(480.000 t) during 1976-1982
only 0,7 % of this material
had been diluted.
In view of the high  contamina-
tion of the  leachate  it  can't
be discharged into the recei-
ving stream, the Paar, a tri-
butory of the Danube, so it has
to be pumped from the retaining
basin into lorry and after
40 km-transport treated  in the
chemo-physical plant and sewage
plant in Ebenhausen. Task of
the treatment is the reduction
of the heavy-metal-content of
the leachate by precipitation
and changing pH-values.

The conventional treatment
makes clear that several con-
taminants can't be reduced in a
biological way or eliminated in
common oxidation processes
(high salt content, COD).
                                89

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Therefore, on behave  of  the
Bavarian Ministry  of  Environ-
ment a research program  was
undertaken for treating  the
leachate by a 2-stage distil-
lation pilot plant in Ebenhau-
sen. In the first  step (acid
distillation) the  contamina-
tion were cristalized and
reduced in a salt  concentrate.
In the second step (alkaline
distillation), the acid  conta-
minants could be reduced
again. The results made  clear
that TOG and COD could be
reduced over 90 %,  particular-
ly by using the discontinues
distillation (reduction  nearly
96 %).

Experience was made,  that
distillation of leachate can
be a reasonable alternative  to
the conventional treatment.  So
the first distillation for up-
scale plant in the FRG will  go
in 1986 in operation  at  the
Schwabach Facility.

The Charges system and
Investments
The disposal costs  in  Bavaria
are reasonable, probably
reflecting the  facts that
initial capital investments
are not being amortized and
that later capital  investments
are subsidized  through inter-
est-free or low-interests
loans. The pricing  formulas
are quite involved  and are
summarized as follow.  Waste
treatment charges are  estab-
lished by process for  each of
the processes used  in  the
major waste categories. The
charges are designed roughly
to cover the transportation
from the collection centres
 and the cost of waste treatment
 for each process.

 Average treatment charges per
 ton (German Marks)
landfilling    EM  75,-
chemo-pnysical DM 120,-
incineration   EM 325,-
- 190,- (depo-
       sition
       in con-
       crete
       jacket)
- 300,-
 1500,- (PCB)
 The hazardous waste disposal
 facilities in Bavaria required
 an investment of DM 120 million
 in the last 15 years. Financing
 is handled through subsidies,
 government loans and favorable
 interest terms (DM 70 million)
 and the company's own recources
 obtained by economic activity.

 CONTROL

 The FRG has a control system ir
 which hazardous waste genera-
 tors can and usually are re-
 quired to initiate a trip-
 ticket,  cradle-to-grave record-
 ing system of special waste
 involving six separate copies.
 Waste haulers,  waste disposers
 and responsible agencies re-
 ceive and/or transmit appropri-
 ate copies. Thus there are
 numerous places for cross-
 checking the kinds and quanti-
 ties of waste as it travels to
 its final destination (see
 Figure 4).

 In Bavaria, nearly 150 000
 trip-tickets are controlled by
 the Bav. Environmental Protec-
 tion Agency with the help of a
 computerized system.
                               90

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                                        Disclaimer



The  work  described  in this paper was not  funded by  the U.S. Environmental

Protection Agency*   The  contents do  not necessarily reflect the views of the

Agency and no  official endorsement should be  inferred.


                                          91

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      HAZARDOUS WASTE COLLECTING AND TREATMENT IN AUSTRIA

      Willibald Lutz
      Consulting Bureau for Life, Environment and Recycling
      Jakob GremdlingerstraGe 22, A-1140 Vienna, Austria

      Friedrich Hubl
      Entsorgungstechnik Ges.m.b.H.
      Operngasse 20b, A-1040 Vienna, Austria
                                  ABSTRACT

   According to the new Federal Hazardous Waste Act that came into force
in 1984, all hazardous and toxic substances must be collected and treated
respectively disposed in proper facilities. Depending on the quantity and
quality of waste there are several collecting and hauling systems available,
In the near future there will be a network of collecting and transfer sta-
tions in the Austrian Provinces, whereas the Siggerwiesen/Salzburg plant
with the annual capacity of 20 000 tons is representative. Most of the ha-
zardous waste is shipped by rail or road to the central treatment plant EBS
in Vienna. In the City of Vienna there is a chemical-physical treatment
plant and a hazardous waste incineration plant with a total capacity of
160 000 tons annually. The excess heat is used to produce electricity and
steam for the central heating system of the city. Due to the new federal
Air Pollution Standard that came into force in 1984 additional flue gas
cleaning devices must be installed, whereby new technologies are under con-
sideration-.
INTRODUCTION AND PURPOSE

The purpose of the paper is to demon-
strate the efforts Austria is under-
taking to improve its environment.
The new Hazardous Waste Act as well
as other new laws, regulations and
standards require the improvement of
existing treatment and disposal
systems and the development of new
technologies.
APPROACH AND PROBLEMS ENCOUNTERED

In Austria there are approximately
400 000 people employed in activities
that generate hazardous waste. As-
suming a specific amount of 280 kg
per employee and year, the total
quantity of hazardous and toxic waste
results in 112 000 tons annually.
Adding other commercial and indus-
trial residues such as oil contami-
nated liquids and solids, other hy-
drocarbonic pollutants, etc. the
total estimated amount of hazardous
waste is 350 000 tons (t/a).
                                    92

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Table 1. ESTIMATED HAZARDOUS WASTE
         GENERATED IN AUSTRIA
hazardous waste
hazardous and toxic
waste
specific quantity
per employee
   t/a
350 000

112 000

      0,28
recommended treatment:
incineration          105 000
physical-chemical
treatment (CP-plant)  140 000
hazardous waste
landfill              105 000

In Austria there are large quanti-
ties of industrial waste not classi-
fied at present as hazardous waste
such as ashes and slag from coal
fired boilers and steel mills. These
wastes amount to several million
tons annually and are landfilled in
more or less controlled ways.

The Austrian Standard tJNORM S 2100,
Catalogue for Special and Hazardous
Waste, describes more than 400 clas-
ses of substances. Each class and
group has a separate code number,
which is also used in the european
common market. The standard QNORM S
2101, Hazardous Waste Requiring
Supervision, contain 144 different
hazardous substances in 12 groups.
All substances mentioned in this
catalogue must be declared by the
owner or generator and be disposed
by an authorized company.

Code No. Substance
13       animal and slaughterhouse
         waste
31       inorganic waste
35       metal waste
51       oxides, hxdroxides-, salts
52       acids, alkaline solutions,
         concentrates
53       herbicides, pesticides
continue:

54
55

57
58
59
97
and Pharmaceuticals
mineral oil wastes
organic solvents, paints,
adhesives, sealings, wax
plastic and rubber waste
textile waste
chemical waste
hospital waste
                Beside all legal and administrative
                problems with the new regulations,
                there is also a lack of proper hazar-
                dous waste collecting and disposal
                facilities.  The few existing plants
                must be extended and adapted to the
                increased environmental requirements.
                The air pollution requirements are
                much more stringent than before.

                Table 2.  EMISSION STANDARD IN AUSTRIA
                	(1984)	._
                                        mg/Nm3
                particulate matter        50
                hydrochloric acid (Cl~)  100
                hydrofluoric acid (F~)     5
                sulfur dioxide (S02)     300
                total lead and zinc(Pb,Zn) 5
                arsenic  (As)              1
                chromium (Cr)              1
                cadmium (Cd)               0,1
                mercury (Hg)	0,1	

                RESULTS

                At present there are several studies
                ongoing to implement the new laws
                and regulations in Austria.  At the
                same time new disposal facilities
                are in the design and construction
                phase. Two of the most advanced
                plants will  be described in  details
                below.

                Hazardous waste collecting and trans-
                ferstation  in Siggerwiesen/Salzburg.

                The Province of Salzburg with a per-
                manent population of 442 000 without
                tourists is  the only one in  Austria
                                    93

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In addition there were existing
agreements with several industrial
firms as well as communities and
other waste disposal facilities in
Austria.

After a two years construction
period the plant was started up on
June 30, 1980. The total investment
and start up costs amounted to $42
million. The plant has its own
energy recovery system and is run-
ning independent from the electrical
grid. Since December 1982 the excess
heat has been sold to the central
heating system of Vienna. During the
first year of operation of the waste
water treatment plant and the in-
cineration plant, problems occured
due to the bad sludge condition and
also political considerations that
resulted in a joint operation
management.

Table 2. EBS DESIGN PARAMETER	

Hazardous waste:
total quantity,     t/a  160 000
burnable,           t/a  100 000
CP-treated,         t/a   60 000
Sludge:
quantity raw sludge,mVa1400 000
dry substance,      %      4-7
calorific value of
the dry substance,  kJ/kg 16 300

Emissions:
particulate matter, mg/m3    100
grey value,          -         1
hydrogen chlorine,  mg/m3    100
carbon monoxide,    mg/m3    500
hydrogen fluoride,  mg/m3      5
total sulfur dioxide,kg/h    325
organic carbon,	mg/m3	50

Process description
Sludge:
The capacity of the EBS plant amounts
to a daily maximum of 3 800 m3 raw
primary and secondary sludge with
5*5% dry substance. The sludge is
pumped from the thickeners of the
central waste water treatment plant
to the sludge holding tanks where a
circular sludge pumping main is in-
stalled. Dosing pumps are feeding
the centrifuges and at the same time
a polymer solution is added into the
front end of the centrifuges. The
filtrate water flows back into the
waste water treatment plant. One
third of the dewatered sludge is
dried in two sludge dryers and after-
words it is mixed with the remaining
dewatered sludge in order to get J5%
dry substance in the mixture. The
mixed sludge is lead into two flui-
dized bed incinerators. The combus-
tion occurs at temperatures of about
850 °C.

Hazardous waste:
The hazardous and toxic waste can be
delivered by rail or road. There are
possibilities for delivery by barge
also, because the plant is located at
the Danube Canal and this option will
be considered in the future. In emer-
gency cases helicopter transportation
is practicable. The hazardous waste
is contained in tanks, barrels or
special vessels and boxes. It is ac-
cepted in different receiving areas
such as a tank farm, barrel storage,
EP-plant, deposit basin, shredder pit
or solid waste pit.

After separation of water in the CP-
plant or in vertical tanks the liquids
are pumped to burners and lances at
the front end of the rotary kilns or
directly into the afterburner
chambers. According to the origin and
composition of solid hazardous waste
it is dumped into the waste pit of
the shredder and the sized material
is conveyed to the large pit of the
rotary kilns. Hospital waste and
other identified solid materials are
dumped directly into the large pit.
A semi automatic grab crane is feed-
ing the charging devices of the
                                    96

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incinerators. The calorific capacity
of each kiln amounts to 102 GJ per
hour and the combustion temperature
ranges between 1 000 and 1 350°C in
order to destroy chlorinated hydro-
carbons.

Flue gas treatment:
The flue gas of the combustion cham-
bers of the sludge dryers is cleaned
in cyclones and tube filters. In
addition one dryer is equipped with
a venturi scrubber.
The flue gases of the four combus-
tion units pass boilers and produce
steam with 350°C and 53 bar pressure.
After cooling down to 240°C the
partieulate matter is removed in
double field electrostatic preeipi-
tators. In addition the two rotary
kilns are equipped with dry scrub-
bers using lime dust. ID fans are
blowing the clean gases into three
stacks, each of them 50m high.
The emission rates and concentra-
tions are limited by the air pol-
lution authority, which is also
controlling them.

Energy recovery:
The four boilers are producing a
maximum of 90 tons per hour steam,
which is utilized in two units of
counter pressure turbines and gene-
rators with a capacity of 4*6 MW
each. Approximately 4Q?o of the pro-
duced electricity is used in the
plant itself. The surplus in heat
and electricity is sold to the cen-
tral heating system of Vienna and
to the central waste water treatment
plant.

Operating experience

During the first year of operation
the EBS management was faced with
a number of unexpected difficulties.
The new Federal Waste Oil Act came
in force on Jannuary 1, 1980. This
act classifies waste oil as a market-
able product without setting standards
for contamination limits. Therefore
the predicted quantity of waste oil
decreased rapidly and was no longer
available. In order to keep a proper
energy balance fuel had to be added.

The design of the EBS facilities and
the economics are based on a balanced
energy input and output. In case of
a decrease in the calorific value of
hazardous waste, fuel has to keep
sufficient burning conditions. The
excess energy is always constant, but
the quantity of residues such as slag,
ash, flue gas varies in accordance
with the material that has been bur-
ned. The following diagram shall
illustrate the correlation.

Figure 2. CORRELATION BETWEEN INPUT
AND OUTPUT IN A WASTE TO ENERGY SYSTEM
  INPUT
fuel
variable    S
                         slao._ash
                         flue gas
                             OUTPUT
               energy
               constant
In the first year of operation 1980/
1981 the input quantity of raw sludge
amounted to 797 000 m3 with 4"8?o dry
substance and after dewatering the
fluidized bed incinerators were fed
with 146 000 tons. In the two rotary
kilns had been burned 39 000 tons
hazardous waste. In order to maintain
the proper energy balance oil fuel
in the range of 19 000 tons had been
added. In 1983 the following hazar-
                                     97

-------
dous waste quantities were burned.
Table 3. HAZARDOUS WASTE
(1983)

organic waste solid
and pasty
organic waste liquid
solvents
halogenated, sulfuric
wastes, poisons, etc.
oilcontaminated soil
inorganic waste
screening residues
barrels
hospital waste
commercial and
industrial waste
waste oil
QUANTITIES
t/a
6 600
17 800
1 100
1 000
3 600
1 000
8 600
900
4 500
13 500
14 400
summary
73 000
In addition to the mentioned
73 000 tons of hazardous waste
(including 14 400 t waste oil as
fuel) the EBS took over 830 000 m'
sludge with 5"4?o dry substance.
The energy output amounted to
270 000 MWh steam sold to the cen-
tral heating system and from a total
of 32 000 MWhour produced electri-
city 11 500 MWhour were used in the
central waste water treatment plant.
The quantity of ash and slag amoun-
ted to 31 700 tons. (Figure 3.)

Future aspects

Due to the increased air pollution
protection requirements additional
air cleaning devices will be in-
stalled in the near future. The new
emission standards are especially
focused on heavy metals in the flue
gas. Each incinerator will be equip-
ped with multi stage wet air scrub-
bers and a central waste water neu-
tralisation and decontamination plant
will be implemented.
The existing CP-plant will be split-
ted up into two plants. In the near
future inorganic hazardous and toxic
waste will be treated in a separate
new plant. This plant will take over
caustic solutions, extraction liquors,
acids, chromates, nitrites, sludges,
etc. to a maximum of 30 000 tons per
year. The existing CP-plant for or-
ganic hazardous waste will be refur-
bished and extended to a maximum
capacity of 50 000 tons annulally.

The CP-plants as well as the incine-
rators are generating residues such
as dewatered sludge, slag and.ash.
Because of the toxicity of these
materials, they have to be deposited
in an absolutely safe and controlled
way together with other hazardous
and toxic solids collected by EBS.
Therefore studies are ongoing with
a multi barriere cassette-landfill.
The waste will be separately deposi-
ted in cassettes according to its
origin and composition. The cassettes
are completely ceiled and equipped
with emission controlled systems.

ACKNOWLEDGEMENTS

  The information in this report has
resulted from many studies, designs
and consulting services as well as
practical experiences of the authors.
Dr. Willibald Lutz is a member of
the commission of the Austrian En-
vironmental Fund and a consultant to
the Minister of Health and Environ-
ment. Friedrich Hubl is the founder
and former shareholder of the EBS-
plant in Vienna. Now he is the head
of a waste management company in
Austria.

                Disclaimer

  The work described in this  paper was
  not funded by the U.S.  Environmental
  Protection Agency.  The contents do
  not necessarily reflect the views of
  the Agency and no official  endorse-
  ment should  be inferred.
                                   98

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10
                                            11.HAIDEQUER5TRASSE
           Figure  3. LAY OUT PLAN OF  EBS-VIENNA (1984)
           1   administration building,
           2   weighbridges
           3   shredder
           4   deposit basin
           5   sludge holding tanks
           6   energy supply area
           7   control center
           8   sludge treatment area
lab  9  waste bin
     10 barrel handling area
     11 tank farm
     12 fluidized bed reactors
     13 rotary kilns
     14 starting steam boiler
     15 lime dosing, ash silo
     16 slag removal
17 cooling plant
18 measuring center
19 collector tunnel
20 pumping station
21 fire fighting station
22 workshop
23 filling station
24 CP-plant

-------
                POLICY TRENDS IN HAZARDOUS WASTE MANAGEMENT
                      IN ASIA AND THE PACIFIC REGION

                                  Nay Htun
                 Regional Office for Asia and the Pacific
                 The United Nations Environment Programme
                          Bangkok  10200, Thailand

                                  ABSTRACT

     In the Asia and the Pacific region, there is increasing awareness of
the need for sound management "of hazardous wastes.  With over half the
world's population, accelerating development programmes and rapid urban-
ization trends, the impacts on environment and human health can be very
serious, if appropriate control and management measures are not imple-
mented.  In the formulation and implementation of policies for managing
hazardous wastes the trend is to overcome a number of major constraints.
These include lack of;- information on the sources, quantity and types of
wastes generated; trained manpower and financial resources; effective
co-ordination amongst the ministries that are involved; specific laws and
legislations; rigorous enforcement and appropriate incentives; specialized
technical know-how and education and training schemes focussed particu-
larly on improving the management of hazardous wastes.

     The paper discusses the issues emanating from generation to final
treatment and disposal from institutional as well as technical
considerations.
INTRODUCTION AND PURPOSE

     The Asia and the Pacific region
is vast and according to the UN
designation, it consists at present
of 39 member countries.  In mid
1983, the region had a population of
approximately 2.6 billion with
average annual growth rates varying
between 1.28 and 2.16 per cent for
East and South Asian countries res-
pectively.  The region's population
is expected to increase to about
3.4 billion by the end of this
century.

     Countries in the region provide
extreme contrasts in almost all as-
pects.  The most and least populated
countries; highly industrialized and
least developed; land locked and
island countries; the highest moun-
tain and deepest ocean; tropical
forests and deserts; largest areas
of mangroves and corals, etc. are
found in the region.

     A common prediction is that
most if not nearly all  countries
will experience significant growth
rates, with the Association of South
East Asian Nations (ASEAN)  countries
in conjunction with the other Pacif-
ic Basin countries and the Republic
of Korea, providing the lead.

     Manufacturing, raw material-
processing, agriculture and infra-
structure developments are seen to
be the major sectors that will be
receiving major emphasis to promote
growth.
                                  100

-------
     It Is clear, therefore, that
irrespective of whatever development
patterns and economic systems the
countries in the region are embark-
ing upon, the problems associated
with hazardous wastes are already
significant in those that are indus-
trialized and will soon be for those
that are fast developing.

     Although awareness of and con-
cern for the impacts of hazardous
wastes are increasing, the level
varies greatly between countries.
However, a growing number of coun-
tries are in the process of formula-
ting policies and strategies to
manage hazardous wastes.

     The purpose of this paper is an
attempt to provide an overview of
the major policy elements which are
being considered as well as the
problems encountered, from the gener-
ation to final disposal/destruction
of hazardous wastes — the "cradle-
to-grave" approach.  Both the tech-
nical and institutional aspects are
discussed.


PROBLEM AREAS

     The major problem areas which
need to be overcome in order to
formulate and implement effective
and pragmatic hazardous waste manage-
ment policies are seen to be the
lack of:- information; resource; co-
ordination;  laws and legislations;
enforcement; incentives; technical
know-how, and education and training.

     Although these problem areas
are no different from those expe-
rienced in the industrialized coun-
tries, the situation in the develop-
ing countries is  accentuated and
compounded because of weak institu-
tional mechanisms for dealing with
general pollution and environmental
issues.  These problems are briefly
discussed in the following sections.

Information

     There is a lack of information
on the sources of hazardous waste,
the quantity and types that are gen-
erated, the disposal methods used and
inventory of storage and/or disposal
sites.  Without such information and
data it is very difficult for nation-
al authorities to develop rational
policies and implement pragmatic
management procedures.

     Thailand, Malaysia and India are
some of the countries that are colla-
ting and compiling waste generation
data.

     While definitive data are not
available on the quantities of haz-
ardous waste generated, the growth
in manufacturing of selected sectors
of industry in India will provide an
indication of the probable increase
in waste streams.
    TABLE 1.  GROWTH PATTERN OF
  SELECTED INDUSTRIES IN INDIA (1)
                            _     _
               Production xlO tonnes

Pesticides
Dyes & Pigments
Organic chemicals
Caustic Soda
Non-Ferrous
1970
3
14
17
304
35
1980
41
31
24
457
83
(Cu, Pb, Zn)
     In Thailand, a 1979-1980 study by
theOffice of the  National Environment
Board showed that wastewater from
                                   101

-------
over 50 percent of Industries con-
tained at least one kind of heavy
metal with concentrations higher
than the limits set by the standard
According to another survey in 1981,
nearly 600 industries, the majority
of which are located in and around
the capital of Bangkok, dispose of
wastes containing mercury, nickel,
chromium and cadmium.

     Acquisition of information and
data can be an expensive and time
consuming undertaking.  Before such
an effort is made, a careful review
of whether such information and data
already exist  in the various minis-
tries, research establishments,
academic institutions and industrial
enterprises  is  undertaken.
Collation of existing information
and data would preclude the need for
unnecessary expenditures.  If infor-
mation and data need to be acquired,
then the specific uses are identified
first, so that only relevant infor-
mation and data would be compiled
and presented in the appropriate
format for the intended use.

Resources
     Most if not all countries lack
adequate resources to manage and
dispose of hazardous v/astes.  This
constraint is much more acute in the
developing countries.  There is
already a shortage, and in many
countries a critical shortage, of
trained and experienced manpower,
facilities as well as financial
resources.

     During the past decade the
number of environmental issues con-
fronting governments and industry
have increased significantly. These
have evolved from site specific and
end-of-pipe pollution control to
global common issues such as ozone
layer depletion and carbon dioxide
build-up, transboundary problems of
acid rain, as well as loss of wild-
life and genetic species.

     The awareness of hazardous
waste problems is relatively recent.
Governments are finding it increas-
ingly difficult to allocate budgets,
since there are other major competing
needs for financial resources,
including budgets for controlling and
abating conventional pollutants.
There is a hesitancy to divert and/or
increase  manpower and resources from
on-going environmental programmes.
Hence, the availability of reliable
information and data is important,
in order for governments to assign
priorities and allocate appropriate
resources.

     A strategy which a number of
countries are considering is a va-
riant of the polluters pay principle,
with the government providing the
supervision and operating the facil-
ities for a fee.

Co-ordination

     Most countries in the region
continue to regard hazardous waste
as primarily solid waste and are
"managing" it under existing insti-
tutional mechanisms.  In most cases
this is done under municipal waste
collection and disposal procedures
and methods.  Industrial wastes are
left to the individual industries to
dispose of and as in the case in Thai-
land and Indonesia, for the Ministry
of Industry to supervise and enforce
any existing regulations.  Hospital
wastes are normally the responsibil-
ities of hospitals and the Ministry
of Health.  Similarly, agrochemicals
and minetailing wastes are the res-
ponsibilities of the Ministries of
Agriculture and Mines respectively.

     During the past five to ten
                                    102

-------
years most countries in the region
have established Ministries and/or
Departments of the Environment.
These new institutions are now begin-
ning to recommend overall policy
guidance, improve co-ordination
amongst the various ministries and
follow-up on enforcement measures.

     Their role in increasing aware-
ness of the problems of hazardous
wastes, using such well reported
cases as the Love Canal and Times
Beach in the U.S. and the Lekkerkerk
in the Netherlands, is beginning to
support the need for better co-
ordination in the formulation and
implementation of policies for
managing hazardous wastes.

Laws and Legislations

     In the region, laws and legis-
lations for the control of hazardous
waste are generally embodied in a
variety of other legislations that
deal with environmental and health
protection, resource recovery,
factory safety, etc.  There are at
present no specific legislative acts
specifically promulgated for hazard-
ous wastes.

    In Japan for example, the Basic Law
for Environmental Pollution Control
enacted in August 1967 provided the
framework for controlling hazardous
wastes.  More significantly the
series of prohibitions on the pro-
duction, use and importation of PCB
between February 1971 and September
1972 (2) underscored the priority
placed by the government on the
issue of controlling hazardous
waste.

     In a large number of countries,
the definition/criteria for
hazardous wastes are still being
discussed and debated.
     While the characteristics most
commonly used to designate hazardous
waste;- toxicity, reactivity, corro-
sivity and flammability are used, for
example in Australia (3), there is as
yet no general agreement.  The system
of an inclusive and/or exclusive
lists (4) for classifying hazardous
wastes is also being contemplated by
a number of countries.

     A trend in an increasing number
of countries is to review existing
legislations and assess whether these
are adequate for the control and
management of hazardous wastes as
well as determine whether there are
any gaps which need to be specifi-
cally filled.

     One particular area which needs
special attention is in the transpor-
tation of hazardous wastes from the
generating source to either interim
storage and/or final disposal sites.
Since transportation by road, rail,
waterways or sea is the responsibil-
ity of many different ministries,
including the Police Department, the
trend is to ensure that any licencing
and manifest systems introduced are
effectively coordinated and enforce-
ment responsibilities clearly dele-
gated and accountable.

     In this regard, interministerial
committees are being established to
enhance cooperation and coordination.

Enforcement and Incentives

     The infringment of laws normally
carry a paltry penalty.  Often it is
less expensive and more expedient to
continue paying the fine than to
incur proper treatment and disposal
costs.  In Japan for example, in 1979,
4,778 of the 5,855 arrests for
pollution offences were connected
with wastes.
                                   103

-------
     While the penalty for violating
 hazardous waste legislations needs to
 be  increased, because of the severity
 of  the effects on human health, there
 should also be at the same time in-
 centives for the waste generators to
 improve and/or change processes and
 operations that do not result in
 hazardous wastes.  Instruments such
 as  tax rebates, subsidies, low
 interest loans could be considered
 by  governments to encourage such
 changes.

 Techn i cal Know- How
  Reduction_at Source

     There is growing recognition,
 based on the experience of the indus-
 trialized countries, that preventive
 policies are in the long run more
 cost effective.  While there is
 av/areness of the availability of tech-
nologies which do not form hazardous
wastes, for example, the use of the
membrane process instead of mercury
cells for  the manufacture of caus-
tic soda, the substitution of PCB's,
and the recycling and recovery of
toxic components of residues, there
is still general reluctance to
change over from conventional pro-
cesses.  This is because of costs,
and only greenfield installations
can consider incorporating such new
processes, as well as the perceived
risks involved with the performance
of such processes.

     Fiscal instruments described
earlier could be used by governments
to promote the use of less hazardous
processes.  Similarly, demonstration
projects could also be constructed
to show the efficacy of recovery and
recycl i ng .
     The majority of the industries
generating hazardous wastes in the
region are of small scale.  Similarly,
those emanating from individual non-
industrial origins, such as from
laboratories and pesticides use are
also small volume at source.  As the
wastes have no economic value, there
is a tendency to store them in used
containers which will be discarded.
The conditions of these containers
are such that they leak readily, dis-
charging their contents.  This was a
case in Thailand where a recent leak-
age of waste ethyl aerylate from old
container drums hospitalized about
300 workers.

     There is scope for the design of
reception centers capable of accepting
the safe storage of small volumes of
hazardous wastes.

     While there are the Recommenda-
tions of the United Nations Committee
of Experts on the Transport of Danger-
ous Goods, which began its work  in
1953, very few countries in the Asia
and Pacific region have used these
recommendations as a framework for
promulgating national regulations.

     With increasing awareness and
concern by governments, industry and
the general public on environmental
issues, the trend will  be to develop
a system of technical and legislative
measures that will be both efficient
and reassuring, securing the safety
of all without excessively penalizing
the economies of production or being
an obstacle to trade.  The developing
countries in the region are learning
from the experience of  the industri-
alized countries and are keen to avoid
the mistakes that have  been made.

  Treatment and Disgosal

     Land filling:-  At first this
would seem to be an option which could
                                     104

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be widely used in countries in the
Asia and Pacific region.  However,
there are now serious considerations,
particularly in the developing
countries because of the difficulties
in securing the land filled site.
Scavenging of waste dumps is a widely
practised occupation in most develop-
ing countries.  Another growing con-
cern is with the potential  contamina-
tion of ground water supplies.

    The resistance of the people to
the planned disposal of thorium hy-
droxide in concrete dump ditches
spread over a 5-hectare site in
Malaysia, is an example of the con-
cern that is emerging with land
filling methods.
benefit of the potential for material
recovery and recycling.
     For wastes which have sufficient
calorific value, such as spent oils
and solvents, and concentrated
organic solutions final disposal by
incineration is considered as a
viable method.  However, at present,
when this disposal method is used,
it is not used effectively.  Combus-
tion is inefficient and often incom-
plete.  The generation of secondary
air pollutants  is  generally not
considered, as should be the case,
for example of chlorinated hydro-
carbons.
     Processes such as neutraliza-
tion, oxidation, reduction and pre-
cipitation are used, even in small
scale industries such as metal
plating and chrome leather tanning.

     There is, however, significant
scope for optimization of these
treatment processes to improve
efficiency.    An important incen-
tive to increase the use of chemical
treatment options  is the added
     With the exception of Japan,
there is very little published infor-
mation on whether this method is used
and also whether the London Dumping
Convention is followed.  In Japan,
ocean dumping is closely regulated
and discharge methods are classified
as either concentration-type or
dispersion -type.  Discharge areas
are designated for industrial hazard-
ous wastes; wastes which are not
returned to the ocean, and wastes
returned to the ocean (5).

     In many countries, it is very
likely that installations situated
near coastal areas are discharging
their untreated wastes directly into
the sea.  Heavy metal contents in
fish and other marine organisms are
evidence of such clandestine prac-
tices.  Although most countries have
laws prohibiting such practices,
enforcement is very difficult.

  Treatment_and_Disggsal__Ogtions

     Most if not all the developing
countries in the Asia and Pacific
region lack sufficient studies and
experience to be able to assess and
determine which option or combination
of  options    will be most appro-
priate to meet national needs.
Presently policies are formulated
primarily based on the reported
information and/or experience of the
developed countries.

     Often technologies are trans-
ferred with very little adaptation
to local conditions.

Education and Training

     The importance of education and
                                     105

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training  in environmental management,
including hazardous wastes is
recognized.  Education and training
are accorded top priority by all
Ministries and Departments of
Environment in the region.

     There is a trend for countries
to consider developing and imple-
menting comprehensive programmes
which encompass both formal and non-
formal strategies.  Audiences, rang-
ing from decision-makers to youth
and the general public are targeted
and print, radio and television media
are used to increase awareness.

     Australia, for example, focussed
on hazardous wastes in its 1984
World Environment Day publicity and
information programme.

     Universities in the region are
also beginning to offer credit
courses on hazardous waste manage-
ment in their education programme.

RESULTS

     The overview indicates that the
industrialized countries — Australia,
Japan and New Zealand— in the region
are already implementing hazardous
waste management schemes, similar in
scope and content to those of other
industrialized countries in Europe
and North America.

     The countries that are fast
industrializing, for example,
Singapore, Republic of Korea, India,
Thailand, Malaysia, Indonesia and
Philippines are increasingly recog-
nizing that there could already be
some hazardous waste problems, but
are uncertain with regard to their
seriousness,  because of lack of in-
formation.  It is clear,however, that
there is no doubt amongst these coun-
tries on the potential  impacts of
hazardous wastes on human health and
the ecosystem, if proper management
and control measures are not insti-
tuted now.  Without exception these
countries are endeavouring to learn
from the experience of all the indus-
trialized countries.  The advice and
information received are carefully
assessed and synthesized and are be-
ginning to be forged and adapted for
national use.

     For countries that are still
primarily agriculture based, there is
still a need to be concerned with the
disposal of used products such as lead
batteries, and containers for. pesti-
cides.  It is not an uncommon sight
to see such containers used as water
cans, with minimal rinsing and/or
deeontami nati on.

     Undoubtedly, hazardous wastes
need to be managed within the context
of an integrated environmental manage-
ment policy and strategy.

     The countries in the region
recognize the need for such an ap-
proach and the policy trends, insti-
tutionally and technically, are begin-
ning to underscore this.

ACKNOWLEDGEMENT

     I am grateful to my associates
in the United Nations Environment
Programme for the useful discussions
on managing hazardous wastes and to
colleagues in the various Ministries
and Departments of Environment in the
Asia and the Pacific region for
sharing their concerns and thinking
on this subject.  However, I take
responsibility for any erroneous
interpretation and the views stated
are my own and do not necessarily
represent the policies of the United
Nations Environment Programme.
                                    106

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REFERENCES
    Sundaresan, B.B.;  P.V.R.  Subrah-
    manyam and A.D.  Bhide,  1983,  An
    overview  of toxic and  hazardous
    waste in India,  in Industrial
    Hazardous Waste, edited by Nay
    Htun and J.W.  Huismans,  Industry
    and Environment  Special Issue  4,
    1983,United  Nations Environment
    Programme, Industry and Environ-
    ment Office, Paris, France,
    pp. 70-74.

    Japan Environment Agency,  1981,
    Quality of the Environment in
    Japan, Environment Agency,
    Government of  Japan,

    Australian Environment  Council,
    1983, Management and Disposal  of
    Hazardous Industrial Wastes,
    AEC Report No. 9,  Australian
    Government Publishing Service,
    Canberra.

    World Health Organization/United
    Nations Environment Programme,
    1982, Hazardous  Waste Management,
    Interim Document 7, Jointly
    published by WHO Regional  Office
    for Europe, Copenhagen, Denmark,
    and UNEP, Nairobi, Kenya.

    Seki, S., 1983,  Policy  and Regula-
    tions on Hazardous Wastes, in
    Report of the  Symposium on Dis-
    posal and Recycling of  Industrial
    Hazardous Wastes,  sponsored by
    the Asian Productivity  Organiza-
    tion, Tokyo, Japan.
              Disclaimer

The work described in this paper was
not funded by the U.S. Environmental
Protection Agency.  The contents do
not necessarily reflect the views of
the Agency and no official endorse-
ment should be inferred.
                                    107

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                THE  DETERMINATION OF FIXATION TREATMENT METHOD
             LIMITS  FOR HAZARDOUS LIQUIDS AND INDUSTRIAL SLUDGES
                           FROM DISPARATE SOURCES

                  E. Dennis Escher, P.E. - Vice  President
                      John W. Newton - Project Manager
                              NUS Corporation
                       Pittsburgh, Pennsylvania  15275


                                  ABSTRACT

The disposal  of industrial  waste  sludges  has been an operating problem  to
industry and landfill  operators for  many years.   In past years, designers
failed to  complete their responsibility  by adequately addressing the disposal
requirements of  the sludges  produced  by  industrial waste  treatment plants.
Most  often,  the waste  treatment plant  operator was  presented  with  a
sophisticated treatment  facility which  produced a  high  quality effluent  but
also produced large  volumes  of raw,  gelatinous sludges with  no  dewatering
equipment and inadequate means for  disposal.  Disposal of  these  sludges  has
been a costly operating problem to  industry.

As landfill  designs and operations became  regulated  in  the United States
during  the  1970's,  the  disposal  costs  for industrial  sludges increased
significantly.    Eventually,  liquid sludges could  no longer be  accepted  at
landfill disposal  sites.   This renewed a  market for  improved sludge dewatering
facilities.     It  also   created  a  new  market  for  solidification  and
stabilization processes  and  for  chemical fixation of  hazardous  liquids  and
sludges.

Many  of  these dewatering and  sludge  solidification/fixation processes  were
evaluated  for use at a new commercial hazardous waste disposal plant.   This
disposal  firm  processes  100,000  gallons  per  day  (gpd)  of  various  hazardous
inorganic  liquids and industrial sludges, mostly consisting  of acids, alkalis,
and plating wastes.

After the  fixation  process was selected,  based  upon general application
tests, a battery of tests  was conducted  to  determine the limit to  which  the
fixation process would treat effectively  various hazardous inorganic liquids
and industrial  sludges.  These  tests were  then used  to  limit the type of
acceptable  incoming  wastes, to  develop plant operating  guidelines, and to form
the basis  of information  to obtain  a  temporary  deli sting from  the  State  and
the EPA, for the wastes  treated at  the facility.

The fixation process selected employs  lime,  cement, and bentonite addition to
the wastes.  The  lime is  used  to optimize pH for  heavy metal  precipitation,
the cement  solidifies the treated  wastes  within approximately  48  hours,  and
the bentonite acts to bind the  metals  by ion exchange as well as reducing the
permeability of  the  fixed  wastes.
                                     108

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The test methods used in the determination of the leaching  characteristics,
the limits of treatability,  the  nonapplicability to some wastes, and the
pretreatment  standards for the fixation used  at  the waste treatment facility
are reviewed  in this paper.
INTRODUCTION AND PURPOSE

The  use  of fixation  treatment
methods to  render  hazardous liquid
wastes to a nonhazardous solid is
hampered,  to a  great  degree, by the
unknown treatment limitations of the
specific  process.    This paper
describes the  tests  and rationale
that  were used  to  delineate  the
treatment limitations of  a  specific
fixation  treatment  process.   The
tests described  herein  were
conducted  in  conjunction with  a
successful  delisting  petition.
The  purpose of  the  tests was  to
define the level of contamination in
raw  liquid  wastes that would cause
the fixated  material to fail the EP
toxicity criteria, to  interfere with
solidification   process,   and  to
address the long-term stability of
the fixed material under rigorous
and natural  weathering conditions.

APPROACH

In  order to  define  the  specific
treatability  limitations  of  the
fixation treatment system, a battery
of spike tests were set up.

It  was planned  that these  tests
would identify the concentrations of
each metal  that  would overload the
solidification/fixation  process  and
cause the treated wastes  to fail the
EP   toxicity  criteria,   thus
establishing a maximum concentration
level that could be processed by the
treatment  facility.    Raw  liquid
hazardous  wastes  from a  variety of
industrial  sources were collected
and  analyzed for  heavy  metals
(barium, cadmium, chromium, lead,
mercury, nickel, silver,  arsenic,
and selenium),  cyanide,  and phenol
content.   The raw liquid hazardous
waste sample was then divided into
three samples, A, B, and C.   Sample
A was  spiked with enough  barium,
cadmium,  chromium,  lead,  mercury,
nickel,  silver,   arsenic,  and
selenium to produce a  concentration
of  0.1 percent  (about  1,000  mg/1)
for each  metal.   Samples  B  and  C
were  similarly spiked to  produce
individual  metals concentrations  of
0.5  percent  and  1.0  percent,
respectively.   Using  this metals
spiking  procedure   produced   a
total  metals  concentration  of  about
0.9 percent in A, 4.5 percent in  B,
and 9.0  percent in C.  (Chromium was
added in the hexavalent form, and
analysis  was conducted for  total
chrofliium.  All metals were spiked  as
the metal  compounds commonly  used
for internal  standards  in  standard
additions  spikes  for chemical
analysis.}

The spiked raw waste samples were
analyzed  to  determine the actual
metals concentration and then  were
fixed.  The fixed samples  were  EP
leached after  24 hours of curing
time and leachate  was  analyzed for
the nine  heavy  metals.   Another
portion  of the raw liquid hazardous
waste   was  divided  into  three
portions  and spiked  with  enough
cyanide and  phenol to  yield the
following  raw waste concentrations:
Sample
Group
          17 mg/1
          4.5 mg/1
          2.9 mg/1
Phenol

0.35 mg/1
1.3 mg/1
1.6 mg/1
                                   109

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These spiked  raw waste samples were
then  fixed and  leached after  24
hours of curing.  The leachate was
immediately analyzed for cyanide and
phenol.
In order to  delineate the  leachate
quality of the fixed  materials over
extended    rigorous   leaching
conditions,  a battery of tests was
set  up.   These  tests  used  fixed
materials   collected  from  an
operational,  full  scale, fixation
treatment  plant.    The  fixed
materials were allowed  to cure for
three days.   The fixed material was
ground to a 150  particle size  prior
to leaching.  After EP leaching, the
samples were  subjected  to the EPA
Multiple Extraction Procedure.  (This
procedure  is  detailed  in  the
Appendix.)

In order to  investigate the long-
term  stability  of  the  fixation
process  under normal   weathering
conditions,  samples were  collected
from nine field test  cells that had
been in place for  six years.   The
field  test  cells were  originally
constructed  and  used to  generate
data  concerning   weathering
conditions and to support the patent
applications  for  the fixation
process.  Samples were collected and
composited  from any discrete layers
which  appeared  in  each  field  test
cell.    The   samples   were  then
subjected to  EP  leaching  and the
leachate  was   analyzed for  cyanide,
barium, cadmium, chromium,  copper,
iron,  lead,   mercury,  silver,
arsenic,  and  selenium.

PROBLEMS  ENCOUNTERED

Prior to the treatability limitation
spike tests, it was observed that in
spiking the raw wastes with all  of
the metals,  the metals  leached or
reacted  to  the EP  leaching  in  a
synergistic manner.  That is to say
that  two  metals  in sufficient
quantities may complex with  each
other to  form a  highly Teachable or
 soluble complex, or a nonleaching or
 insoluble complex.   It was assumed
 that  these  interferences could be
 identified  by  comparing  the
 constituent  analyses  of the  spiked
 raw wastes and fixed wastes and  in a
 graphic analysis of total raw waste
 content  versus leachate  content.
 These types  of effects were noted by
 some  variations in apparent barium
 fixed  material  content in each of
 the three trials (approximately 0.1,
 0.5,  and 1.0 percent).  Arsenic and
 selenium variation  from spiked raw
 waste  acid  to spiked  fixed  waste
 occurred  in only  the  0.5 percent
 addition trial.   Each  of  these
 apparent synergistic effects formed
 insoluble complexes.

Another problem encountered was that
 the multiple leach tests may not be
 representative for phenol because of
 possible biological digestion of the
 phenol.   This  did not  appear to be a
 problem once the data were examined "
 for a mass balance of phenol content
 in the fixed material to the phenol
 content in the multiple leaches.

 RESULTS

 Inorganic Solidification/Fixation
Treatabllity Limits

After the analysis was  completed on
the  inorganic  spike  tests  and
graphically  plotted  to compare
 liquid raw waste metal content to
fixed  material  EP leachate  metal
content, it was apparent  that the
nine metals  could  be  put into three
groups.   The first group were those
 with metals  with leachate concentra-
tions not significantly elevated by
 the metals spiked to the raw wastes.
These metals included barium, lead,
 silver,  and  arsenic.  (The data are
presented in  Table  1.)  The treata-
bility limit of these metals was not
approached  by  the  metal concentra-
 tions  spiked  to the raw wastes and
remained below 1 rag/1.

The  second  group of  metals  were
those with  leachate  concentrations
                                     no

-------
 linearly  elevated by  the metals
 spiked to the  raw wastes.   These
 metals include mercury, cadmium, and
 selenium (see  Figure  1).   From
 Figure  1  and  Table  1  it can  be
 observed that mercury,  cadmium,  and
 selenium leached  from  each of the
 three spiked samples above the EP
 toxicity limit.  However, each of
 the  three  metals  leached  in a very
 nearly linear  proportion.    The
 cadmium and selenium leaching curves
 intersect  the  level of  EP toxicity
 allowing  the  leaching limits  to  be
 estimated for each of  the metals.
 The  mercury  leaching curve did  not
 intersect  the  EP  toxicity limit of
 mercury indicating that  the  curve
 probably has an inflection point at
 the  very low end of the  curve.   This
 level  of  raw  waste  mercury
 concentration  versus  leachate
 mercury  concentration  should  be
 investigated further  in order  to
 locate the  fixation  limit for
 mercury.
   LEACHATE METALS CONCENTRATION VS.
   RAW WASTE METALS CONCENTRATION
    t<« VllUl

    ***'"'*
              jgji|*IJ4  mi*
                   e.w

                   f.IM
                             u«a  um
The third group are metals where the
leachate concentrations  responded
nonlinearly  to  the  metals spiked to
the  raw wastes.   These  metals
include  nickel  and chromium.   (See
Figure  1 and Table  1.)  Figure  I
shows that  both chromium and nickel
leachate concentrations increased in
a  nearly exponential  manner once  a
"saturation  point"  was  reached.
However, both  of  these curves also
intersect the  EP  toxic limits for
the respective  metals.
    2000 4QOO  6000  8000 IOOOO I20OO I40OO
       RAW WASTE CONCENTRATION (nig/li
The overall purpose of the metals
spikes   was  to  determine  the
concentrations  that  would
conservatively overload  the fixed
process and cause  the treated wastes
to fail  the EP toxicity  criteria.
The results of these tests are given
in Table  2.


             Table 2
       Approximate Limits  of
      Solidification/Fixation
Metal

Barium
Lead
Silver
Arsenic

Cadmium
Selenium

Mercury

Nickel
Chromium
   Raw Waste
 Concentration
_ (tng/1)

   6,600
   8,820
   3,900
   12,000

   1,700
     500

     600

   8,000
   8,200
                                         111

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Cyanide and Phenol Solidification/
Fixation Leaching Characteristics

Early  in  the development  of this
fixation  process  it was suggested
that organics and cyanide would not
be  adequately  treated  by  the
process.   Exhaustive analysis  of
potential   raw  waste  streams
Indicated  that phenol and  cyanide
were  common  contaminants  in  the
incoming  raw wastes.  In order to
obtain  some idea  of  the  leaching of
these two  contaminants,  spike tests
and  leaching  tests  were also
conducted.  Three raw waste samples
were spiked with the concentrations
shown in Table 3A and subsequently
leached.

             Table 3A

    Spiked
  Raw Waste           Leachate
Concentrations      Concentrations

Sample  A:

Cyanide -  17              0.62
Phenol  - 0.35            0.15

Sample  B:

Cyanide -  4.5            0.25
Phenol   -  1.3            0.29

Sample  C:

Cyanide -  2.9            0.076
Phenol   -  1.6            0.75

Concentrations in mg/1.

From the graph in Figure 2, it can
be seen that cyanide appears to be
readily Teachable from the fixed raw
waste.   However,  if  the   EPA Public
Health  Services  recommended limit
for the protection of drinking water
(200     g/1) is applied to these
results,  an  apparent limit of 3.8
mg/1 of cyanide can  be  effectively
treated  by  the  fixation process.
Limits  for cyanide  in terms of EP
  toxicity have  been  established but
  in  terms of  its  possible  hazardous
  nature due  to  reactivity,  EPA
  advises that  a solid should  contain
  no  more than 20 mg/kg of cyanide.
  The highest concentration  of  cyanide
  added to the  raw waste was  17 mg/1
  which, when fixed, leached only 0.62
  mg/1.
0.7
LEACHATE CYANIDE CONCENTRATION VS
RAW WASTE CYANIDE CONCENTRATION
                 LIMIT FOR PROTECTION OF
                 DRINKING WATER
  0   2   4   6   8   10   12   14   16 17
    RAW WASTE CYANIDE CONCENTRATION (mg/1)
 From the graph in  Figure  3, it can
 be  seen that phenol appears to  leach
 in   an  exponential   manner  when
 compared to the amount of phenol
 spiked to the raw acid.  However,
 none  of  the  leachate phenol
 concentrations  exceeded   the EPA
 Public  Health  Services  recommended
 limit  for the protection of drinking
 water  of  3.5 mg/1.   From  the
 apparent  slope of   the  leaching
 curve,  it  is hypothesized  that this
 limit  would  be  reached  rather
 quickly   at   higher   phenol
 concentrations
                                      112

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  0.8-
 . 0.7-
O 0,6-
§0.4-
  0.3-
a.
u
  O.Z-
LEACHATE  PHENOL CONCENTRATION VS.
RAW WASTE PHENOL CONCENTRATION
                        FIGURE 3
    0   O.25  O.SO   0.75   1.0  1.25  1.50  1.75
       RAW WASTE PHENOL CONCENTRATION (ma/I)
   Multiple Extraction Data

   The previously discussed spike tests
   outline the  effect  that raw waste
   contaminant content  has  on  leachate
   of the fixed  material, but in only a
   single leaching step.   This  leads to
   the  question,  "What effect  will
   prolonged exposure  of  the  fixed
   material  to  an  aggressive  leaching
   media  have over a longer period of
   time?"  In an attempt to answer this
   question,   a  set   of  multiple
   extractions were   conducted  as
   outlined  in  the Approach  section
   above.

   The data  from these  inorganic tests
   were  analyzed  by   graphing  the
   individual EP toxic  metals  leaching
   over  the  multiple extractions and
   graphing  the  total  EP toxic metals
   over the  multiple  extractions.   The
   data  from the cyanide  and phenol
   multiple  extraction  tests  were
   analyzed  by  comparing  the  total
   amount  of each  contaminant leached
   during  the extraction procedure  to
   the total  amount of each  contaminant
   in the sample prior to leaching.
Inorganic  Multiple Extraction Tests

The inorganic multiple  extraction
results are  presented  in  Table 3B.
The multiple  extraction procedure is
a  very  rigorous  leaching procedure
and is  probably more severe  than
natural  conditions.  The majority of
metals  did  not  leach  to   any
significant  degree.  These metals
included barium,  cadmium,  mercury,
silver,  hexavalent   chromium,
arsenic,  and  selenium. Four of  this
group of metals  (arsenic, barium,
mercury, and  selenium) probably did
not have sufficient quantity  of the
metal  in the  treated sample to leach
in  any great  quantity.   Of  the
remaining  metals  in this  group,
cadmium,  silver,  and   hexavalent
chromium showed  low leaching rates.
The  remaining  three  metals,
chromium,  lead, and nickel showed an
excellent  resistance to leaching
after being  fixed.   All three  of
these  metals  were  present  in
relatively high  concentrations in
the fixed sample  with  chromium
(Figure 4)  and   lead  leaching  at
below   detection   limit
concentrations.   The   leachate
concentration of nickel  is   the
only leachate metal  concentration 1n
the tests  that does not  approach or
go below  detection limits in  the
last four extractions  (Figure 5).
However, at  no time  do  any of the
nickel  leachate concentrations
approach   the  EPA  toxicity or
drinking   water guidelines  of
approximately 20 mg/1,  with  the
leachate  values  at  or  below  0.5
mg/1.

To gain some idea  of the overall
quality of  the  leachate  under
multiple extraction, the total EP
toxic   metals  concentration  was
graphed for  the extraction   step
(Figure 6).   This graph shows  that
the leachate metals concentration
stabilizes after  the second round of
leaching, to a total EP toxic metals
concentration of  approximately  0.64
mg/1.    This  level  of leaching is
below the total  metals  allowed in
                                       113

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                                               TABLE 3B

                                    HUUIPU EXTRACTION tC«CKAU ANALYSIS («g/l)


Cd 0.03 <.01 <.01 <.01 f.Ol <.o
Hg .0031 <.0002 (.0002 <,0002 <.0002 .OC
H -04 ,01 .01 <.Q1 <.01 <.Q
Cr M .22 .09 ,1» ,29 ,3
Hi <.OS .30 .22 .13 .16 .1
HI ,50 .10 .23 .04 .08 .0
Cr*' .Cm .012 <.02 <.02 <.02 .0
Al .006 <.001 <.001 .001 <.001 .OC
S< ,002 <.002 <.OC2 <,002 .002 <.K
Toul
Of Sarplc If
.2 -1 .2 .2 <1 100
<.0l <.01 <.QI <.01 6,0 1.0
HI <.0002 .0002 .0002 .0012 <1 0.2
<.Q1 <.01 <,01 <.01 $.0 S
(.02 <.02 <.02 <.02 152? S '
«.06 <.06 «,06 «.06 1(5 4
> .38 .«8 ,36 .«2 2020 —20
0 <.02 <.02 <,02 (.02 0.1 5
3 <,001 .001 .002 <.001 .05 i
2 <.002 .003 <-OOJ <,002 t.t 1.0
MW,Tmjl C«IN4CnON OMCMIUW OMCtMnUnON
TOTW. cr W.L [* imtc MCULS L£ACMIWI
5Mk *-M**«B»Htn«»i«»it« = tra ^ «.«*»«j»tt*iuit *n**JO!*el»nuiK*l«cvo«MntiwwMI««r H»MM»
!" \ / \ s*"
\) — IOTM «(i«,i ttttmi** tr f*»wyrro*!*i^«*«*
\ ti>ia*«M n til *-t/t
V-~_ -~*>**^_^- t-tss"
..„.„_/ ,,„,„,,


Employing the sample weight and
leachate volumes, a rough mass
balance of metals was calculated.
, , The percentage of the total weight
"W.tKs.f C1NMCIIO* KCKCL C*MCX»T*A1KM ^ A t i i i , . .
«" ,. of metals leached during the
| \ aa»;^5.'3S.?-tS-j;"" •'""">' /\ , complete multiple extraction
I" \ / \/^ procedure was 3.5 percent of the
L, \ / weight of metals contained in the
J \ / fixed sample. If the metals had
I" \ /\ 1 leached consistently at Primary
r \ / \ / Drinking Water Standards, more than
I"- \ / ^ percent of the metals contained
" ^ — """"•"-*/ OSMSIJ would have leached.
the Primary Drinking Water Standards
which are 100 tiroes less  than the EP
toxic limits.
                                           114

-------
 Cyanide  and Phenol Multiple
 ExtractTon Data

 Cyanide and  phenol  were  also
 monitored in the multiple extraction
 tests.   The data  are  presented in
 Table 4. To  analyze these data, a
 mass balance  was  performed for both
 contaminants.   The possible mass of
 the contaminants  leached was then
 compared to the  total  mass  of
 contaminants  contained by  the fixed
 sample.   The mass balance of both
 cyanide and phenol  shows that the
 weight of contaminant  in both cases
 is   well within  the  maximum  and
 minimum mass leached.   This can be
 interpreted to  mean that  the fixed
 process provides   very  little
 treatment of these contaminants.
 that  were treated  and  placed  in  the
 field cells were from the same types
 of waste generators that provided
 raw wastes  for  the spike and  multi-
 leach  tests.   The treated material
 produced in these early tests was
 not yet  optimized  so  it can  be
 assumed   that  fixed  materials
 produced at optimum conditions would
 exhibit a lower leaching rate.
                 F«L£ V



            FIEIO TtiT CUl EP IWCH TEST
                                                               High     jotf
                                              to

                                              u

                                              Cr
                                              M

                                              S.
          0.04

          O.M

          0-CI

          <,s

          0-03

          cr.Mt

          n.wi
8. OS

0.3?

 .IS



 .OS

 .016

 .flll
0.01

1.93
                                                                     0.0)

                                                                     1. 001
               Q.Q*i


               G.3*
    In caTcolatiag awigtt, iar *ain*s NIov tfit detectlca Ifait
    ,Mfm «»T»»a to M *l t!Kt MBit, !.*. <.1U • .Ql H$/l.
                        l*mt t*Ml ?0 tW I
       • IIM, l.«. t.flt • 0,01.
EP leachate  Resultsfrom Five Year
Old Field  Test Cells

Composite  samples from the 16 field
test cells were  EP leached and the
leachate  was analyzed  for the  EP
toxic metals (see data Summary Table
5).  Recall  that these  field  test
cells were exposed  to  the year round
weathering conditions  of western
Pennsylvania for six  years.   These
field test cells were  initially used
in  the  research  and  development of
the  fixation process.   The  tests
were generally conducted  under
differing  mixing,   and  reagent
conditions that were  no_t  optimized
at  the time.  The raw liquid wastes
The   total  EP   toxic  metals
concentration leached was plotted
for  each  of  the  16 field cell
samples  (see  Figure 7).  No  values
were above 5 percent of the EP toxic
limit.   The high and low  limits  for
these  total  EP metals  were then
averaged  to give  the  average total
leaching EP  metals  of  0.25 mg/1
after six years of weathering. This
leaching figure is lower than  the
total leaching figure generated  in
the  multiple  extraction  procedure,
but of the same order of magnitude.
It would also be  expected that as
available  metals  were leached from
the fixed material that  the  rate of
leaching would  decrease.   These
data, therefore, compares reasonably
well  with  the  multiple leaching
data.
                                        115

-------
           IPMCUU UWOnW PROM «ltWIOU> HIU> TOT CtUJ
                                           Since  the fixation system selected
                                           and employed  in these  tests  passed
                                           the rigorous  set of tests outlined
                                           by the paper with apparent ease, the
                                           positive  physical  properties  of the
                                           process  were  not  investigated.   In
                                           another  case  where  the fixation
                                           process did not  perform  so well  in
                                           treating  the prospective raw  wastes
                                           or if additional data were  needed
                                           for  the  design  of  a  leachate
                                           treatment plant,  the  physical
                                           aspects  of  the  fixation process
                                           should also be evaluated.
CONCLUSIONS AND COMMENTS

This  battery of fixation process
evaluation   tests    can   be
characterized   as  a   rather
conservative approach,  being that
the tests  do not actually address
any   of the beneficial  physical
properties  of  fixing  a  liquid
hazardous waste.

The tests  presented in this paper
evaluate   only  a  few   of  the
beneficial  mechanisms and aspects of
fixing  a liquid hazardous waste.
The  EP   leachate  tests,   multiple
extraction  tests,  and EP  leachate
tests of weathered  material do not
address  the low  permeability of the
fixed material,  the limitation of
available surface leaching area of
the fixed material,  or the capacity
of the fixed material  to absorb and
hold potential leachate.   In order
to understand the optimal   physical
effects  of  solidifying/fixing liquid
wastes,  another round of similar
tests could be  conducted without
grinding the  fixed material to pass
a  150   screen and  to  subsequently
compare  such results to the results
presented here.
REFERENCES

1.  40 CFR, Part 261, Appendix II,
    EP Toxicity Test Procedures.

2,  40 CFR,  Part 261,  Appendix III,
    Chemical Analysis Test Methods.

3.  Multiple Extraction Procedure,
    Method  1320,  47
    November 28, 1982.
FR  -  52682,
4.  Test  Methods  For  Evaluating
    Solid Haste,  Physical/Chemical
    Methods, EPA Publication SM-846.

5.  EPA,  Methods  of   Chemical
    Analysis of Water and Hastes,  EPA
    Method 200.0 Standard Additions.
APPENDIX

* A synthetic acid rain solution was
  prepared by adding a 60/40 weight
  percent mixture  of sulfuric and
  nitric acid  to distilled water
  until  a pH  of  3.0  (+0.2)  was
  achieved.

• The  solid  phase  of  the  fixed
  sample  after  EP  leaching  was
  weighed  and  placed  in  the  EP
  extractor with 20  times its weight
  of the synthetic  rain extraction
  fluid.
                                     116

-------
• The mixture and  sample was then                    Disclaimer
  agitated  for  24  hours  at   a
  temperature maintained  between  68      The work described  in this paper was
  and  104  F.  The pH was recorded 5      not funded by the U.S. Environmental
  to 10 minutes prior to extraction      Protection Agency.  The contents do
  and at  the end  of extraction.           not necessarily  reflect the views of
                                        the Agency and no official
• The contents  at the end of  the  24      ment should be inferred!
  hour extraction  period  were  then
  separated  into  its component
  liquid and solid phases as with
  the separation procedure in  the  EP
  leach.

• The extract was then analyzed for
  barium, cadmium,  chromium,  lead,
  mercury,  nickel,  silver, arsenic,
  selenium,  cyanide,  and  phenol.

t The solid  phase remaining was  then
  subjected  to  reextraction  in
  accordance with the above steps  an
  additional  eight  times.
                               117

-------
             DEVELOPMENT AND APPLICATION OF ON-SITE TREATMENT
                  TECHNOLOGIES FOR SLUDGE FILLED LAGOONS

  D.S. Kosson, R.C, Ahlert, J.D. Boyer, E.A. Dienemann and J.F. Magee II
                Rutgers, The State University of New Jersey
            Department of Chemical and Biochemical Engineering
                               P.O. Box 909
                           Piscataway, NJ 08854


                                 ABSTRACT

     Over a period in excess of ten years, several industrial sludges were
disposed of by landfilling.  During the period of operation, the composition
and rate of deposition of sludges varied.  The resulting lagoon contains in
excess of 30*000 cubic yards of sludge.  Leachate from the sludges has
impact on local groundwater.

     Acidic, neutral and alkaline aqueous extraction of the sludges has been
examined.  Contact times and sludge-to-extract ratios are important
parameters.  Sequential extractions result in decreasing extract concentra-
tions, implying exhaustive leaching of the lagoon is possible.

     Biological treatment of naturally occurring leachate and representative
extracts has been examined.  Aerobic microbial treatment with unacclimated
and acclimated sewage organisms results in varying degrees of organic
removal.  Removals of up to sixty-five percent have been achieved.  A soil
based microbial treatment process has been examined, also.  Degradation
efficiencies in excess of ninety-five percent have been demonstrated.


INTRODUCTION                            range from solid to gelatinous in
                                        physical state and are layered in
     Over a decade or more, several     the lagoon.  Leachate from the
sludges were disposed of by landfill-   sludges has impact on local ground-
ing.  During this period of operation,  water.
the composition and rate of deposition
of sludges varied.  The resulting            Clean-up of the lagoon is viewed
lagoon contains more than 30,000 cubic  as consisting of two interrelated
yards of sludge.  The principal         problems,.  The first problem is the
sludges in the lagoon are primary       removal of contaminants from the
(lime neutralized) and secondary        lagoon, without major excavation.
(biological) sludges from treatment of  The second problem is treatment of
effluent from diverse chemical manu-    the stream containing the stripped
factoring operations.  The sludges      contaminants, including both organic
                                   118

-------
and inorganic species,,  Towards these
ends, several extractants and treat-
ment processes are being considered.
Acidic, neutral and alkaline aqueous
extractants have been examined for
removal of organic contaminants.
Aerobic and soil-based sequential
aerobic/anaerobic microbial treatment
processes have been examined for
renovation of the resulting waste-
water stream.

FORCED EXTRACTION OF SLUDGES

     Extraction experiments were
performed to examine applicability of
forced extraction for controlled
removal of organic species from the
primary and secondary sludges.
Studies were conducted by shaking a
measured amount of sludge with a
quantity of extractant.  Extractants
employed were acidic, neutral and
alkaline aqueous solutions.  The
sludge-extractant mixture was shaken
for the period specified for each
case.  The mixture was centrifuged
and the supernatant solution decanted.
Subsequently, the supernatant was
assayed for pH, EC, TOC and TDS.
Parameters evaluated included time to
equilibrium, extractant pH, and
extractant to sludge mass ratios.

     Time to equilibrium was deter-
mined by allowing single extractions
to interact from 6 to 48 hours.  A
minimum contact time of 24 hours was
required to attain equilibrium; see
Figure 1.  Sequential extractions of
a quantity of sludge with fresh
extractant were performed.  At the
conclusion of each extraction step,
the extraction mixture was centrif-
uged and the supernatant decanted.
Acidic, neutral and alkaline
extractants were used.

     Extraction of the secondary
sludge proved to be independent of
extractant pH; however, extraction of
the primary sludge was dependent on
pH.  Typical results are presented in
Figure 2.  Alkaline extractant
proved to be much more effective
than neutral or acidic extractants.
A 0.1 N solution of sodium hydroxide,
at pH 13, achieved the best removal
of organic matter.  Satisfactory
results were achieved with NaOH
solutions, at pH between 11 and 12,
also.  Order of magnitude reductions
in caustic required and extract TDS
make extraction at pH between 11 and
12 desirable.

     The ratio of extractant volume
to sludge mass was varied, also.
Ratios as small as 2 ml extractant
per gram moist sludge were found to
achieve high organic species removal,
Extract TOCs as high as 3200 mg/1
were observedt  Typical results of
sequential extractions are presented
in Figure 3 and Table 1,

     Sequential extractions of fresh
quantities of sludge with the same
extractant were performed, also,
At the conclusion of each extraction
step, the mixture was centrifuged
and decanted.  The supernatant was
added to fresh sludge and shaken.
The cycle was repeated to determine
the maximum extract TOC attainable
Equilibrium was reached with five
extraction steps.  TOCs as high as
8900 mg/1 were observed.

AEROBIC BIODEGRADATION OF LEACHATE
AND SLUDGE EXTRACTS

     Aerobic biodegradation of
leachate and forced extracts was
examined.  Optimum conditions for
maximum degradation of organic
species were sought.  Experimental
parameters considered were pH,
glucose as a supplementary carbon
source, and initial inoculum
concentration.
                                     119

-------
     A stock culture of microorganisms,
acclimated to a feed solution contain-
ing both glucose and leachate derived
organic carbon (GOC and LOG, respecti-
vely) was used.  This culture was
derived from the secondary sludge of
a municipal sewage treatment plant.
Feed for the stock culture had a 1:1
ratio of GOC to LOG.  This ratio
varied between 0:1 to 1:1 during
experimental trials.

     The stock culture was fed 12
hours before each experiment.  This
insured that the inoculum would be
active at the start of the experiment.
Shake flasks (250 ml) containing a
total volume of 50 ml each were used.
The shaker speed was 250 RPM.  This
volume and shaker speed were chosen
to provide sufficient oxygen
transfer.

     All experimental solutions
contained the following:

     • 500 mg C/l as LOG

     • 5% by volume buffer (1 M KH?
       P04 and 1 M KpHP04 mixed to
       obtain pH - 7)

     ••625 mg/1 (NH4)2S04

     • 200 mg/1 MgS04«7H20

     • 9.375 mg/1 CaCl2-H20

     • 350.0 mg/1
     • 625 mg/1 FeCl3«H20

     Initial glucose concentration was
varied between 0 and 1250 mg/1,,
Initial inoculum concentration was
varied between 5 and 20 percent, by
volume.  It was determined that pH
must be buffered to between 7.0 to
7.9 during experimentation.  Samples
were taken at the beginning and
conclusion of each experiment.
Samples were analyzed for GOC, TOC,
OD, volatile fatty acids, ammonia
and nitrogen.

     Typical experimental results
are presented in Table 2.  All
glucose present was utilized during
microbial degradation.  Microbial
growth was proportional to initial
glucose concentration.  Glucose was
required for cell growth to occur.
Variations in glucose concentration
did not enhance degradation of
organic species in the leachate or
extract.  Further, varying inoculum
concentration did not influence
degradation of organic species in
the leachate or extract, either.
TOC reduction for typical test cases
was approximately 50 percent.  TOC
reduction did not result exclusively
from reductions in volatile fatty
acid concentration.

SOIL-BASED MICROBIAL TREATMENT OF
LEACHATE

     Laboratory soil column experi-
ments were conducted to examine the
ability of mixed microbial popula-
tions in soil to biodegrade leachate
from the lagoon.  Biodegradation has
been demonstrated to occur
sequentially through aerobic and
anaerobic microbial metabolic
processes [1].  Aerobic processes
dominate near the surface of the soil
column, where diffusion of oxygen
from the atmosphere drives the
gradient.  Anaerobic processes
dominate at increased depths, where
oxygen is depleted through aerobic
respiration.  Data obtained from
laboratory scale investigations are
readily extrapolated to field
responses [2,3].

     Factors examined were packing
type and influent TOC concentration.
These factors directly
influence process variables includ-
                                    120

-------
ing hydraulic flux, solute adsorption,
pH and overall organic carbon reduc-
tion.  A 2x2 factorial experimental
design, with two replications per cell
was employed.  Nutrients were added
to the leachate so that available
substrate was the limiting factor for
biodegradation.  Influent pH was
adjusted to between 7 and 7.5, also.
Column beds were 3 inches in diameter
and 18 inches in depth.  Experimental
procedures were in consonance with
those employed in previous column
studies [3].

     Two column packing types were
chosen.  Ore column packing was a
sandy loam.  This packing was
selected based on previous experience
with a similar soil*  The second
column packing was the same sandy
loam mixed thoroughly with 30x140
mesh granular activated carbon (6AC),
at a soil to GAC ratio of ten to one,
by weight.  Activated carbon was
employed to enhance solute retention
time through increased adsorption.
Increased column permeability
resulted from the addition of GAC,
also.

     The second factor examined was
influent TOG concentration<  Influent
organic carbon concentratio'n directly
affects the extent and rate of
microbial growth<,  If this growth
becomes excessive, formation of
excessive bioslime may occur,
decreasing column permeability.  The
rate of bioslime formation is not
necessarily directly proportional to
influent TOC concentration [1].  It
is possible that increased influent
TOC concentration results in
decreased bioslime growth, without
affecting overall TOC removal.
Therefore, two influent leachate
concentrations were employed.  Column
influent was nominally either full or
half-strength leachate.
     Experimental results are
summarized in Table 3.  One repre-
sentative response for each
experimental condition is provided;
replication within experimental test
conditions was excellent.

     Column packing had considerable
influence on hydraulic flux.  Columns
packed with the soil and GAC mixture
exhibited an average hydraulic flux
almost four times that of columns
packed with the sandy loam only.
Within packing types, hydraulic
response was independent of organic
loading.

     Columns packed with soil only
displayed decreasing hydraulic flux
as the experiment progressed.
Eventually these columns became
plugged for prolonged periods.  This
probably resulted from formation of
an extensive microbial bioslime,
expecially near the surface of the
column.  A second contributing factor
may have been a sodium-calcium
imbalance in the soil.  Columns
packed with the soil-carbon mixture
exhibited relatively constant
hydraulic fluxes throughout the
experiment.

     The most significant measure
of treatment effectiveness is
cumulative TOC removal.  It is the
difference between the total
influent TOC mass and the total
effluent TOC mass integrated over
the duration of the column operation.
It accounts for both concentration
and hydraulic flux variations,  TOC
removal on a cumulative mass basis
for representative columns is
presented in Figure 4.

     On a cumulative mass basis,
columns receiving full-strength
leachate removed approximately twice
as much organic carbon as those
receiving half-strength leachate,
                                    121

-------
within the same packing.  Thus, for a
particular packing, the overall mass
of TOC removed was directly propor-
tional to the influent TOC concentra-
tion, given similar hydraulic fluxes.
However, at each influent TOC
concentration, columns packed with the
soil -carbon mixture removed more than
three times the organic carbon removed
by those packed with soil only.  This
resulted primarily from differences
in hydraulic flux.  In all cases the
overall percent organic carbon
removal was in excess of 90 percent.

CONCLUSIONS

     Controlled, forced extraction of
the sludge-filled lagoon appears to
be a favorable process for increas-
ing the rate of removal of organic
species from the lagoon.  Extraction
with 0.001 N aqueous sodium hydroxide
solution results in high extractant
TOCs without excessive TDS.  Aerobic
microbial treatment of the resultant
wastewater stream achieves approx-
imately 40 to 50 percent reduction
in TOC,  TOC reductions in excess of
90 percent can be achieved through
treatment with a soil -based,
sequential aerobic/anaerobic system.

REFERENCES
1.
    Kosson, D.S, and RfC= Ahlert,
    1984, In-situ and On-site Bio-
    degradation of Industrial Land-
    fill Leachate, Environmental
    Progress . Vol. 3; No. 3, pp» 176
2,
    Kosson, D.S. and R,C, Ahlert,
    1983, Treatment of Hazardous
    Landfill Leachates Utilizing
    In-situ Microbial Degradation,
    Management  of Uncontrolledj
    Hazardous Waste Sites. HMCRI ,
    pp. 217-220o
                                        3.  Kosson, D.S., E.A. Dienemann and
                                            R.C. Ahlert, 2984, Treatment of
                                            Hazardous Industrial Landfill
                                            Leachate Utilizing In-situ
                                            Microbial Degradation. Hazardous
                                            Wastes and Environmental
                                            Emergencies. HMCRI, pp. 289-292.
                                                         Disclaimer

                                           The work described in this paper was
                                           not funded by the U.S. Environmental
                                           Protection Agency.  The contents do
                                           not necessarily reflect the views of
                                           the Agency and no official endorse-
                                           ment should be inferred.
                                    122

-------
                TABLE 1    SEQUENTIAL EXTRACTIONS OF SLUDGES
Sequential Extractions:  Extractant/Sludge ratio: 2:1
                         Extractant: 0.001N NaOH (pH = 11)

Primary
Sludge


Secondary
Sludge


Extract
1
2
3
4
1
2
3
4
pH
8.2
7.9
8.0
8,2
11.9
12.0
12.1
12.1
9/1
1.92
0.81
0.92
0.44
9.34
4.81
3.50
1.88
TDS
zmg/g wet
3.85
5.47
7.31
8.18
18.67
28.29
35.29
39.04
mg/1
124
93
70
56
3126
1275
549
243
TOC
imgC/g wet
0.25
0.43
0,57
0.69
6.25
8.80
9.90
10.30
                                    123

-------
            TABLE 2.  AEROBIC MICROBIAL DEGRADATION OF LEACHATE
% Reduction    30.2
                              Initial Glucose Concentration  (mg/1)
                         250       500       750       1000       1250
pH
initial
final
OD
initial
final
TOC (mg/1)
initial
final
GOC (mg/1)
initial
final
LOG (mg/1)
initial
final

7.50
8.56

2.37
2.40

195
136

0
0

195
136

7.50
8.41

2,47
3JO

279
143

68
0

211
143

7.50
8.31

2.47
3.60

399
146

. 168
0

231
146

7.50
8 25

2.40
4,00

489
139

268
0

221
139

7.50
8.14

2.34
4.40

593
137

372
0

221
137

7.50
7.98

2.37
4.85

707
133

488
0

219
133
32.2
36.8
37.1
38,0
39.3
                                   124

-------
                 TABLE 3.  LABORATORY SOIL COLUMN RESULTS
                         Column #2      Column 13      Column #7      Column #8
Packing Type             Soil+GAC       Soi'J+SAC       Soil Only      Soil Only
Leachate Feed          Half-strength  Full-strength  Half-strength  Full-strength
Influent TOC               350            700            350            700
 (mg/1)
Average Hydraulic          28.2        .   28.2            7.8           7,8
 Flux (1/sqm/day)
Average TOC                11.1           22.0            3,5           6.7
 Reduction (g/sqm/day)
Overall TOC                94.2           93.8           97.7          97.3
 Removed {%)
                                   125

-------
                    TIME TO EQUILIBRIUM
1000-
900-
800-
700-
600-
^2" 500-
jZ1 WO-
0 300-
0
*~ zon-
100-

(
	 _Q 	 , , .. 	 	 	 B
0 Secondary Sludge




o____-e — — ~~~~ Primary Sludge



Extractant: 0.1N NaOH (pH=13

5 10 ]S ZB 25 30 35 40 45 50
                              TIME (hrs.)
                               Figure 1
                  CUMULATIVE TOC REMOVAL
  1*1  D  0.1N H2S04
O)
14-


12-


10-


 8-


 6-
cn
     O  Distilled water
     A  0.1N NaOH
                                   Secondary Sludge
                           EXTRACT
                          Figure  2
                             126

-------
  2300-1
  2000-
  1500-
             Extractant Volume/Sludge Mass Ratio
                               Secondary  Sludge
                               0.001N NaOH  (pH=ll)
                               n 10:1
                               O  5:1
                               A  2:1
                               Extract
                             . Figure  3
                        CUMULATIVE TOC  REDUCTION

                                     (Integrated mass basis)
                                                            LC#3
cr>
  1000-
   500-
     0    10    20    30
                         40    SO    60    70

                               TIME  (days)
                              Figure 4
BO    so    iao   no
                               127

-------
                                           Expansion
                                             Valve
                                                          Cooler
                                              Compressor
                                     a.
                             ~-\Ng Gas
                                    b.

                 Figure 1.  Artificial ground freezing by brine
                 (a) and liquid nitrogen (b).
Using a computer program  and  pub-
lished cost data, they concluded
that the time required for  soil
freezing plays an important role  in
the overall costs.  The time  factor
depends on  characteristics of the
site such as soil water content,
soil texture, groundwater depth and
flow, soil chemistry, temperature
and precipitation.  Most  of this  in-
formation is routinely collected
during site investigations.
Experimental Method

    Plexiglass columns  (Figure 2)
12.5 cm in diameter and 80 cm in
height were filled with dredge
material from Green Bay, Wisconsin,
after spiking with either heavy met-
als or semivolatile organics.  The
PH of the material was 7.0 and
oxidizable organic mater was 4.70%.
The metals added were Cd, Zn, Cu  and
Ni in concentrations ranging from
                                      130

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                 2" Styrofoam
                      Insulation
               Plexiglass
                Column
                                                      Thermocouple
                 Adjustable
                  Baffles
                          Figure 2.   Experimental setup.
400 to 800 pg/g dry soil.  The  or-
ganics included chloroform, benzene,
toluene and tetrachloroethylene in
concentrations ranging  from 40  to 45
ug/g dry soil.  The water  content of
the sediment prior to freezing  was
160-170% w/w on a dry weight  basis.
Control treatments (no  chemicals
added and/or no freezing/thawing)
were included for comparison.   The
columns were instrumented  with  ther-
mocouples to measure the soil
temperature at depth.   Leachates as
a result of gravity flow were col-
lected and metered during  the
thawing period, and subsamples  were
analyzed.  No water was added to the
columns during the experiments.  At
the conclusion of the experiments,
soils were sectioned and subsamples
were analyzed.  Metals  were  analyzed
by Inductively Coupled  Plasma (ICP)
and organics were determined  by ex-
traction with tetraglyme and
analysis on a gas chromatograph-
mass-spectrometer   (HP  5992  QC-MS)
equipped with a purge and  trap •
sampler (HP 7675A).  Deuterobenzene
(C,Dfi) in tetraglyme was added to
each sample as an internal standard
just, prior to purging.

     Freezing the soil  was conducted
gradually and freezing  direction:was
from the bottom up.  The soil  tem-
perature during freezing ranged from
-1.8° to -16.0 C.  The  rate  of frost
penetration was recorded using a
thermocouple array and  a data
logger.

RESULTS

Consolidation

    Figure 3 shows the  vertical dis-
tribution of soil water content in
selected frozen, unfrozen  and
                                      131

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    -50
 Water Content (%)
IOO         ISO
200
   8O»—
                        Figure 3.  Soil water content  in the
                        frozen treatment (A), after one  freeze-
                        thaw cycle (B, D), three freeze-thaw
                        cycles (C)» and unfrozen treatment  (E).
                                                        30
                                                        20
                                                        10
                                                                              !
                                                                            4
                                                            X
                                                            \
                                     40      80
                                    Elapsed Time (days)
                                    120  0
                                                     20     30
 Figure 4.  Concentration of heavy metals in leachate from unfrozen  treatment
  (A), after one  cycle of freezing  (B) and during three cycles of freeze-thaw
  (C).
frozen-thawed treatments.   After 120
days the water content  in  the un-
frozen treatment decreased from 160-
170% to 80-95% which  is about 60% of
the initial conditions.  Freezing
and thawing the sediments  decreased
the water content  to  lower values
                           than those obtained under  natural
                           drainage and in significantly  less
                           time.  For example the sediment  sub-
                           jected to one cycle of freeze-thaw
                           reached 80-90% water content in
                           about 20 days and the sediment sub-
                           jected to three cycles of  freeze-
                                      132

-------
thaw reached a  water content  of  60-
75% in 36 days.  Because of  the time
savings, freezing and thawing  can be
a cost effective way of drying con-
taminated sediments in lagoons to
allow heavy equipment to enter the
sites and remove the materials.

Metals

    Figure 4 shows the leachate con-
centration of Zn, Ni, Cd and Cu from
the unfrozen sediments and from the
frozen-thawed treatments as  a  func-
tion of time.  In the leachate from
the unfrozen treatment, the  metal
concentrations were in the following
order:  Zn > Ni > Cd > Cu.   In the
frozen-thawed treatments, the  order
of metal concentration was similar,
except that Ni > Zn.  Freezing and
thawing sediments apparently in-
creased the amounts of Ni in the
soil solution compared to the  un-
frozen control.  In general, most of
the metals added to the slurry were
sorbed on the sediments.  Only a
small portion of the added metals
was leached.  The amounts leached
depended on the type of metal  and on
the number of freeze- thaw cycles.
Cu concentrations in the leachate
were the lowest of the four.   While
freezing and thawing increased the
amount of Cu in solution, the  in-
crease was not substantial.  Cd and
Zn concentrations in leachates were
higher than Cu, and one cycle  of
freeze-thaw did not increase Cd and
Zn concentrations in the leachate.
However, three cycles of freeze-thaw
(Figure 4) increased the Cd  in the
leachate from about 5 mg/1 to  about
7 mg/1 and the Zn  from 7 mg/1 to 15
mg/1.

    The mechanisms involved  in metal
retention by sediments include sorp-
tion, precipitation and complex-
 ation.   Stevenson and Ardakani  (12)
 reviewed the relative stabilities of
 metal-organic complexes of some
 trace metals and found at pH 5 they
 were in the order Cu > Pb > Fe > Ni
 > Mn > Co > Zn.  The order of metal
 concentration in the leachate from
 the unfrozen column is the reverse
 of their stability constants. This
 indicates that metals may have
 formed complexes with insoluble or-
 ganics such as fulvic and humic
 acids.   However, freezing and thaw-
 ing nay have increased the
 solubility of Ni but had little or
 no effect on the other metals.

 Organics

     Figure 5 shows the concentration
 of the volatile organics in the
             40         80
             Elapsed Time (days)
I2C
Figure 5.  Concentration of
chloroform  (A), benzen (B), toluene
(C) and tetrachloroethylene in
leachate from the unfrozen treatment
during 120 days.
                                      133

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                                  Chloroform (/xg/g soil)

                              20     40      60      80
                 100
                  Figure 6.  Chloroform concentration in soils
                  kept frozen (A), one cycle of freeze-thaw
                  (B), unfrozen (C) and after five cycles of
                  freeze-thaw (D).
leachates from the unfrozen  treat-
ment and from the treatment
receiving five freeze-thaw cycles.
With the exception of  one  sample,
the order of concentration in  both
treatments was chloroform  >  benzene>
toluene > tetrachloroethylene.
Concentrations of the  organics in
the leachate were higher from  the
unfrozen treatment than from the
frozen-thawed treatment.   This means
that freezing and thawing  as con-
ducted in these experiments  from the
bottom up would decrease groundwater
contamination for these four
organics.  The concentration of
these organics in the  leachates is
inversely related to their
octanol/water partition coefficients
(K  }.  These values for chloroform,
berSene, toluene and
tetrachloroethylene are 93,  135,
490 and 615, respectively  (10).
    Figure 6 shows  the  effect  of
freezing and thawing on the  con-
centration of chloroform in  soils.
These concentrations were obtained
at the conclusion of each treatment.
The vertical distributions of  ben-
zene and toluene were similar  to
that of chloroform,and  the data are
not presented.  The vertical dis-
tribution of chloroform indicates
that the frozen soils contained the
highest concentrations.   Also, a
redistribution of chloroform oc-
curred during freezing.   Initially
the profile was homogeneous, and the
concentration of chloroform  was 40.1
pg/g dry soil.  The low concentra-
tion of chloroform  in the frozen
soil at some depths may be due to
ice lenses, and the high peak  con-
centration (about 70 pg/g) is
probably due to rejection upon
freezing.  The lowest soil
                                     134

-------
                              Tetrachloroethylene (/ig/gsoil)
                             20     40      60      80
                                    T
                  100
                    801-
                  Figure 7.  Tetrachloroethylene  concentrations
                  in soils kept frozen  (A), after five cycles
                  of freeze-thaw  (B) and unfrozen (C).
chloroform concentrations were  found
in the treatment receiving five
freeze-thaw cycles.  Since the
leachate from this treatment con-
tained the least amount of
chloroform, it was concluded that
chloroform was lost to the atmos-
phere by volatilization.  The data
from the columns that received  1,2,3
and 4 freeze-thaw cycles support
this finding.  Jenkins et al.  (9)
reported on the fate of organics in
overland flow soils.  They found
that decreasing the temperature from
25.7°C to 2.5°C decreased the rate
of soil and plant removal of these
organics.  However, they did not
test the effect of freezing and
thawing.  It seems that soil freez-
ing from the bottom of the columns
caused upward movement of organics
and their accumulation in the soil
surface in high enough concentra-
tions to enhance the flux to the
atmosphere.  Upon thawing, downward
movement of organics may have oc-
curred, particularly  through the
macropore channels  formed  during
freezing and thawing.

    The effect,of freeze-thaw on
tetrachloroethylene in  soils (Figure
7) was similar to the other  three
organics except  that  the atmospheric
loss of tetrachloroethylene  was
less.  This may  be  due  to  the
stronger binding of
tetrachloroethylene with soil con-
stituents as evidenced  by  its higher
K   value of 615 compared  with 93,
135 and 490 for  chloroform,  benzene
and toluene, respectively.

ACKNOWLEDGMENTS

    This work was financially sup-
ported by the U.S.  Environmental
Protection Agency (EPA), Containment
Branch, Land Pollution Control
Division, Hazardous Waste
Engineering Research Laboratory,
Cincinnati, Ohio, and the  U.S. Army
                                      135

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Cold Regions Research and
Engineering Laboratory  (CRREL),  un-
der Interagency Agreement DW 930180-
01-0.  The information  contained in
this paper represents the authors'
opinions and not necessarily those
of EPA or CRREL.  Citation of  brand
names is not to be used for promo-
tion or advertising purposes.  The
authors wish to thank Janet
Houthoofd, EPA Project  Officer,  for
her support and Larry Perry of CRREL
for analytical assistance.
REFERENCES

1.  Bishop, S.L., 1971.  Methods  for
treating wastes from water treatment
plants.  New England Water Works
Association, 85, pp!0-24.

2.  Bishop, S.L. and G.P. Fulton,
1968.  Lagooning and freezing for
disposal of water plant sludge.
Public Works, 99, pp94-96.

3.  Burd, R.S., 1968.  A study of
sludge handling and disposal.
FWPCA, U.S. Department of the
Interior, Publication WP-20-4.

4.  EPA, 1984.  Review of in-place
treatanent techniques for con-
taminated surface soils.  Volume 2:
Technical evaluation.  EPA-5401 2-
84-003a.  Cincinnati, Ohio.

5.  Fulton, G.P., 1970. New York
community improves water supply
systems. Water and Sewage Works,
117, pp!44-147.

6.  Geller, S.Yu, 1962. Desalting of
water by natural freezing for farm
use. Izvestiya Akademii Nauk, SSSR,
Seriya Geograficheskaya, No. 5, pp
71-77.
7.  Heller, S.J., 1939. New method
to obtain fresh water in the desert.
Problems of Physical Geography No.
VII NSSR., Translation by Heinze,
Saskatchewan Research Council.

8.  Iskandar, I.K. and J.M
Houthoofd. 1985.  Effect of freezing
on the level of contaminants in un-
controlled hazardous waste sites.
Part 1.  Literature review and
concepts.  Proceedings, Eleventh
Annual Research Symposium,
Cincinnati, Ohio, 29 April - 1 May,
1985.

9.  Jenkins, T.F., D.C. Leggett,
L.V. Parker, J.L. Oliphant, C.J.
Martel, B.T. Foley, and C.J. Diener,
1983.  Assessment of treatability of
toxic organics by overland flow.
CRREL Report 83-3.. US Army Cold
Regions Research and Engineering
Laboratory, Hanover, NH.

10.  Lyman, W.J., W.F. Reehland,
D.H. Rosenblatt, 1981. Handbook of
ChemicalPropertyEstimation
Methods;  Environmental Behavior of
Organic Compounds, McGraw-Hill Book
Company, NY, NY.

11.  Neely, N.S., J.J. Walsh, D.P.
Gillespie and F.J. Scuf,  1981.
Remedial action at uncontrolled haz-
ardous waste sites.  In Land
Disposal;  Hazardous Waste,
Proceedings 7th Annual Research
Symposium, 16-18 March,
Philadelphia, Pennsylvania,  pp 312-
319, EPA 600-9-81-0026.

12.  Stevenson, F.J. and M.S.
Ardakani,  1972.  Organic matter
reactions involving micronutrients
in soils.  pp79-114.  In J.J.
Mortvedi, P.M. Giordano and W.L.
Lindsay  (Eds.), Micronutrients in
                                     136

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Agriculture.  Soil Science Society       14.  Sullivan, J.M., D.R. Lynch  and
of America, Madison, Wisconsin.          I.K. Iskandar, 1984,  The economics
                                         of ground freezing for management  of
13.  Stinson, D.L., 1976.                uncontrolled hazardous, waste  sites.
Atmospheric freezing for water           Proceedings, 5th National Conference
desalinization.  In: Gray F. Bennett     on Management of Uncontrolled
(Ed.), jfeter 1976.  I;  Physical,        Hazardous tfaste S ites.
Chemical Wastewater Treatment.
AICHE Symposium Series, 166, vol.
73.
               Disclaimer

 This paper has been reviewed in
 accordance with the U.S. Environ-
 mental Protection Agency peer and
 administrative review policies and
 approved for presentation and publi-
 cation.
                                     137

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                 WASTE  DISPOSAL  BY HYDROFRACTURE AND APPLICATION OF THE
                    TECHNOLOGY TO THE MANAGEMENT OF HAZARDOUS WASTES

                                           by

                 Stephen H. Stow, C.  Stephen Haase,  and Herman  0. Weeren
                             Oak Ridge National Laboratory*
                                       P. 0. Box X
                               Oak Ridge, Tennessee 37831


    A unique disposal method, involving hydrofracturing, has been used for management of
liquid low-level radioactive wastes at Oak Ridge National Laboratory (ORNL).   Wastes are
mixed with cement and other solids and injected along bedding plane fractures  into high-
ly impermeable shale at a depth of 300 m forming a grout sheet.  The process has
operated successfully for 20 years and may be applicable to disposal of hazardous
wastes.  The cement grout represents the primary barrier for immobilization of the
wastes; the hydrologically isolated injection horizon represents a secondary barrier.
At ORNL work has been conducted to characterize the geology of the disposal site and to
determine its relationship to the injection process.  The site is structurally quite
complex.  Research has also been conducted on the development of methods  for monitoring
the extent and orientation of the grout sheets; these methods include gamma-ray logging
of cased observation wells, leveling surveys of benchmarks, tiltmeter surveys,  and
microseismic arrays.  These methods,  some of which need further development, offer
promise for real-time and post-injection monitoring.  Initial suggestions are  offered
for possible application of the technology to hazardous waste management  and technical
and regulatory areas needing attention are addressed.


INTRODUCTION AND PURPOSE                     new injection facility was put into oper-
                                             ation in 1982.  A total of over 1.5 mil-
    At Oak Ridge National Laboratory         lion curies of radioelements has  been dis-
(ORNL), low-level radioactive wastes are     posed of; the principal nuclides  are
                                                      Cs'3
routinely disposed of by a process termed    Sr^O and Cs'3?  although others,  including
"hydrofracture."  The liquid wastes are      H3, Co60, Ru'06, and isotopes of U, Am,  and
mixed with cement and other solids to form   Pu, also occur in the wastes.  This pro-
a slurry that is pumped under pressure       cess represents the only permanent geo-
through an injection well into underlying    logic disposal of nuclear wastes  in the
strata.  The slurry follows fractures in     United States.
the strata and sets to form a solid grout,
which contains and immobilizes the               The disposal operation is unique and
radioelements.                               is based on the common practice of hydro-
                                             fracturing, which is routinely used by the
    This process has been successfully       petroleum industry to increase porosity
developed at ORNL over the last quarter      and permeability in reservoir rocks by
century.  Initial development work was       fracturing the rocks with water injected
performed at test facilities; in the mid-    under pressure.  It appears that  this
1960s, the process became operational.  A    technique may have potential  application
*Research sponsored by the Office of Defense Waste and Byproducts Management,  U.S.
Department of Energy under contract No. DE-AC05-840R21400 with Martin  Marietta Energy
Systems, Inc.  Publication No. 2532, Environmental Sciences Division,  Oak  Ridge National
Laboratory.
                                         138

-------
to the management of some kinds of hazar-
dous wastes, especially  if alternative
methods to shallow  land  burial are
sought.  Thus, our  purpose is to discuss
the basic principles of  the hydrofracture
program at ORNL and to offer initial
thoughts on the application of the tech-
nique to hazardous waste management.

THE HYDROFRACTURE PROCESS

    A complete review of the history of
the hydrofracture operation and a descrip-
tion of the process can be found in pre-
viously published works  (1-3).  The pro-
cess is a large-scale batch operation
(Fig. 1).  Liquid wastes are stored in
                  WELLHEAD TOWER

             WASTE STORAGE TANKS'
is slotted at a depth of approximately
300 m.  Fractures in the host rock, a
shale of  low permeability, are initiated
along bedding planes by pumping a few
thousand  liters of water into the well;
this is followed immediately by the
slurry, which spreads radially from the
injection well along the fractures.  The
slurry sets to form a thin (less than a
few cm) grout sheet that extends up to
several hundred meters from the well.  No
grout sheet has been detected more than
220 m from the injection point.  Later
injections are made through slots cut at
shallower depths in the well, thus allow-
ing maximum use of the host injection
strata.

                         ORNL-OWG 81-10255*
    GRAY SHALE-
Fiqure  1.  Conceptual  drawing  of  the Hydrofracture Facility at Oak  Ridge  National
           Laboratory.  Surface facilities,  the injection  well, one cased observation
           well,  and grout  sheets are depicted.
 underground  tanks  and  disposed of typi-
 cally  every  one  to two years.   The waste
 solutions, which are alkaline  and 1-2 M
 NaNOs,  are blended with cement and other
 additives to form  a slurry,  which is
 pumped under approximately 20-HPa pressure
 into the cased injection well.  The casing
     Disposal  is normally done over  a two-
day  period  in two  eight- to ten-hour
shifts.  The  total volume  disposed  of
ranges from 350,000  to  700,000  1.
Although some operational  problems  have
arisen over the years,  the technique has
been highly successful.  A major reason
                                           139

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 for this  success is that the engineering
 and operational  aspects of this technique
 are not unique but rather are standard
 practice  1n the  petroleum industry.

     The costs for disposal  at ORNL are
 approximately $0.30/1.   About half of this
 is  operational cost,  including dry solids
 and personnel.   The other half represents
 amortization of  the capital  cost ($5.4
 million)  of the  facility prorated for dis-
 posal  of  40 x 1061  of waste.   The costs
 are sensitive to process parameters  (batch
 size,  injection  rate, etc.),  which were
 chosen to fit ORNL  requirements.

 PRINCIPLE OF HASTE  ISOLATION

     The basic objective of the ORNL  hydro-
 fracture  program is to  effectively isolate
 the wastes  from  the accessible environ-
 ment.   This 1s achieved through immobili-
 zation of the wastes  in a variety of
 ways.   The  cementitious waste carrier is
 the primary barrier and 1s tailored  to
 retard the  two principal  isotopes  that
 occur  in  the wastes,  Sr90 and Cs^/.  Highly
 sorbing illitic  clay  is added to  help
 retain the  Cs137.  Most of the Sr90
 occurs as a find-grained precipitate in
 the waste;  this  precipitate  is physically
 entrapped in the cement and Sr9"  is
 largely immobilized in  this fashion.  The
 secondary barrier is the shale, which has
 a high content of illite.  If isotopes
 such as Cs'3' should escape the grout,
 they should readily be  sorbed by the
 shale.  Equally  important is  the fact that
 the  100-m-thick  host shale formation is of
 low permeability, contains small amounts
 of  groundwater,  and 1s  removed  from  any
 fresh-water aquifer by  over 100 m  of
 intervening strata.

    One of  the most significant aspects of
 the waste isolation operation at ORNL is
 the  generation of bedding plane frac-
 tures.  It  is critical  that the radio-
 active slurry remain in  the impervious
 host horizon  and  not travel through  verti-
 cal fractures into strata that might have
 hydrologic  communication  with the  environ-
ment.  As noted  later, the great mechani-
 cal anisotropy of the shale and the  fact
that the  injections are apparently shallow
enough so that the least principal stress
is vertical are factors that cause the
nearly horizontal bedding plane frac-
tures.  The production of fractures with
this orientation represents one of the
most significant differences with the
standard hydrofracture methods used in
industry, where the fracturing is done at
much greater depths with the intent of
producing vertical fractures that cross
many strata.

SITE SELECTION CRITERIA

Idealized Criteria
    A set of idealized geologic criteria
that should be considered in selecting a
site for a hydrofracture facility has been
developed (2,3).  The criteria are similar
to many used in the selection of reposi-
tory sites for high-level commercial
nuclear wastes (4).  For instance, a
properly located hydrofracture site should
be in an area that is tectonically stable
(low frequency of earthquakes,  no volcanic
activity or recent faulting, low rates of
uplift) and has few, if any, natural
resources that might be sought in the
future.  The injection horizon should be
thick and laterally extensive enough  to
contain and to help isolate the wastes,
and it should be hydrologically isolated
from the accessible environment.  The host
strata and waters contained within should
have geochemical characteristics that
enhance Immobility of the wastes through
retardation, precipitation, or formation
of colloids, and should produce horizontal
(or nearly horizontal) bedding plane
fractures.

Characteristics of the ORNL Site

    The site at ORNL, although  selected
prior to systematic identification of
these idealized siting parameters,
conforms to them fairly well.  A detailed
description of the site geology has been
published by Haase et al. (5).   The
injection horizon is the Pumpkin Valley
Shale, which is a formation in  the Lower
Paleozoic Conasauga Group.  The shale is
                                          140

-------
highly impermeable  (0.01  -  0.001 milli-
darcy [1,2]),  approximately 100 m  thick,
highly sorting for  some nuclldes,  well
bedded, and can be  easily fractured  along
bedding planes.  The  area is tectonically
stable and does not contain known  mineral
or energy resources.

    Structurally, the  site  is quite  com-
plex.  It lies on the  leading edge of the
Copper Creek fault, a  major thrust fault
in the Valley  and Ridge Province;  a  number
of inactive cross-strike  tear faults occur
within hundreds of  meters of the facili-
ty.  The Pumpkin Valley Shale dips at 15
to 20° and contains common  small tight
folds; it is well jointed,  and bedding
plane slippage has  occurred during defor-
mation.  The joints appear  to be the con-
trolling factor in  groundwater movement.
In spite of the complexity  of the  site
geology, it does not appear to have  had
any detrimental effect on the successful
disposal operations at the  site.

    A program  is currently  under way to
more fully clarify the subsurface  hydrol-
ogy of the site.  Deep (500-m) monitoring
wells have been drilled,  and  hydrologic
testing of the injection  horizon and other
strata is under way.   Recent  work  (6)
shows that groundwaters from  the injection
horizon and surrounding strata are highly
saline, containing up  to  190,000 ppm total
dissolved solids.  The dominant constit-
uents are Na, Mg, Ca,  and Cl.  The salin-
ity decreases upward 1n the wells.   No age
data are yet available on the groundwater.

DEVELOPMENT OF MONITORING PROCEDURES

Monitoring Methods

It appears certain that if  the hydrofrac-
ture technique is to be considered for
future disposal operations,  including
disposal  of hazardous  wastes, sensitive
and accurate monitoring schemes must be
developed and applied  so  that the  distri-
bution and fate of the wastes can be
understood.  When the  ORNL  injection
facilities were constructed, cased obser-
vation wells were installed between 30 and
100 m from the injection well.  These
observation wells intersect the injection
zone and are logged with a gamma-ray
detector after each injection.  By com-
paring the gamma-ray profiles between
injections, it is possible to determine
the depth and orientation of a grout sheet
and get some general information on its
extent (1-3).

    During a series of recent bimonthly
injections, research was conducted on the
development and application of ground
deformation and microseismic surveys as
monitoring techniques.  Recent articles
(7,8) describe these techniques.  The
ground deformation approach is based on
the principle that subsurface fractures
produced by hydrofracturing create a mea-
surable deformation at the surface.  The
shape of this deformation reflects the
orientation of the fracture (9,10).  Two
methods have been examined for measurement
of ground deformation at ORNL:  (1) precise
leveling of benchmarks and (2) tiltmeter •
surveys.

Precise Leveling

    Leveling surveys have been conducted
for eight recent Injections.  A total  of
75 benchmarks up to 700 m from the
injection well  were surveyed before and
after each injection.   For the October
1983 injection, a fairly representative
one, deformation is characterized  by
uplift of up to 2.5 cm; the area of maxi-
mum uplift is slightly south of the well.
Such a configuration indicates that the
fracture rises to the north along  the dip
of the shale.  This orientation is
expected, as it is in  the direction of
least lithostatic pressure and along bed-
ding planes.  The orientation can  be con-
firmed by the gamma-ray logs from  the
observation wells.  A leveling survey
taken 30 days later showed that the uplift
had decayed to approximately 50 percent of
its initial  value and  had shifted  slightly
to the north.  Surveys from other  injec-
tions are similar, but the shape of the
surface deformation may vary.
                                          141

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 Tiltmeter Surveys

     A series of eight tiltmeters was
 Installed in shallow wells 125 and 200 m
 laterally from the injection point to mea-
 sure ground deformation during the October
 and November 1983 injections.  The instru-
 ments are capable of detecting injection
 of the first few thousand 1  of water, and
 they accurately recorded the uplift and
 deformation throughout the injections.
 During the 30-day period after the October
 Injection, a subsidence of the uplift was
 recorded,  corresponding closely with the
 leveling  data.   Modeling of  the tiltmeter
 data,  in  an effort to determine the orien-
 tation of  the subsurface fracture, how-
 ever,  has  not produced an orientation that
 corresponds with actual  measurements from
 the gamma-ray logging.   Currently used
 models are for  homogeneous,  isotroplc
 media;  the stratigraphy at the ORNL site
 is  highly  heterogeneous  and  anisotropic.
 Work is continuing to more fully refine
 the models.

 Hicroseismic  Arrays

     A  third method of instrumental  moni-
 toring  involves  detection  of microseismic
 signals associated with  the  injection.
 This approach  is based on  the principle
 that the fracturing  process  should produce
 seismic signals;  with  properly placed geo-
 phones, it  should be possible to  monitor
 the fracture  as  it propagates.  Thus  far,
 this effort has  provided useful  informa-
 tion on the mechanisms of  fracture forma-
 tion and has  shown that  seismic activity
 continues for weeks  after  an  injection.
 These data  indicate  that the  strata  over-
 lying the  injection  zone undergo  mechani-
 cal relaxation after the induced  stress of
 an  injection.  The microseismic method  has
 not yet been developed at  ORNL for determ-
 ination of  the extent and  orientation of
the fractures.

Overview

    There is considerable  work yet to be
done on development  of monitoring  tech-
niques, especially those that provide
real-time data during an injection.   The
 two methods  that do provide such data
 (tiltmeter,  microseismic) show promise; of
 the two,  the tiltmeter method appears to
 be better developed at present.  Stow
 et al.  (7) provide  a relative evaluation
 of the  techniques.   While it is antici-
 pated that future hydrofracture disposal
 operations may require installation of
 real-time monitoring systems, absolute
 techniques,  such as gamma-ray logging,
 will probably also  be required.

 CONSIDERATION OF HYDRQFRACTURIN6 FOR
 HAZARDOUS WASTE MANAGEMENT

     In  this  final section, two general
 topics  will  be addressed:  (1) ways in
 which the hydrofracture method might be
 used for  some types  of hazardous waste
 management,  and (2)  technical  and regula-
 tory aspects  that need to be addressed if
 the method is applied to hazardous waste.

 Use of  the Technique for Hazardous Hastes

    It  is felt that  the hydrofracture
 technique may have  significant potential
 for disposal  of certain types of hazardous
 wastes.   Because the operational aspects
 of  the  disposal  operation are fairly rou-
 tine, attention  is directed here toward
 waste forms and  carriers that are compat-
 ible with the injection process and the
 host formations.

    It may be  possible to use the method
 for disposal of  certain heavy metals.   For
 instance, chromium could be precipitated
 as  the highly  insoluble sulfate, or other
 transition metals might be fixed by che-
 lating agents.   The  insoluble salts or
 chelated metals  could then be mixed with a
 cementitious carrier and injected.   Cement
 might also be  useful as a carrier for  PCBs.

    There is no  reason why materials other
 than cement might not be considered as
 waste carriers.  Polyacrylamide grouts
might prove to be chemically compatible
with certain wastes  and thus offer  suf-
 ficient isolation potential.  Alterna-
 tively,  phenol or amine polymers might be
 developed as waste forms and carriers  that
                                         142

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 could be pumped  into an  injection zone
 before polymerization.

    For certain  wastes,  it might be feas-
 ible to produce  a microencapsulated waste
 form that could  be mixed with cement or an
 organic-based carrier for disposal.  The
 costs of microeneapsulation would probably
 dictate use of such a method for only a
 limited number of very toxic wastes.  Par-
 ticle size should probably be kept below
 1 mm.

 Technical andRegulatory Considerations
 and Needs

    If the QRNL  hydrofracture technique is
 considered for permanent disposal of
 hazardous waste, the existing technical
 data base is inadequate  to provide
 assurance that the process is environ-
 mentally safe, as determined by current
 statutes.  There are a number of technical
 areas that must  be pursued to provide the
 data that will be required for use of the
 technology.  Because one of the principal
 factors in waste isolation by this method
 is the creation  of (nearly) horizontal
 bedding plane fractures  and because little
 is known of the behavior of such fractures
 in rocks, research must be directed toward
 fracture behavior in anisotropic media.
 This and other critical rock mechanics
 issues relative to hydrofracturing are
 discussed by Doe and McClain (11).  A
 related issue is the determination of the
maximum volume that can be injected into a
 single well.

    Work must also be continued on devel-
 opment and refinement of real-time moni-
 toring techniques.  Such monitoring is
 critical to ensure that fractures that
form during disposal do not break a con-
 tainment horizon and intersect horizons
 that are connected to the accessible
 environment.

    Finally, research should be directed
 toward study of the long-term stability of
 the injected hazardous waste.  Ground-
waters at injection depths may be highly
 saline and have corrosion and complexation
 potential.   The long-term interaction of
 such waters  and wastes should be
 understood.

    It  is  also appropriate to note the
 need for consideration of the regulatory
 status  of  injection wells.  Certainly many
 regulations  could apply to a hydrofracture
 site, including its surface and subsurface
 facilities.  At present, federal under-
 ground  injection regulations (EPA regula-
 tions for the Underground Injection Con-
 trol Program, 40 CFR 144) and similar
 statutes at  the state level may be applied
 to the  process because the technology
 Involves subsurface injection of wastes.
 Underground  injection regulations are
 written for  disposal of liquids, including
 hazardous wastes, into porous and per-
 meable  aquifers; the wastes mix with non-
 potable groundwater and slowly disperse.
 The concept of waste isolation by hydro-
 fracturing,  as noted previously, is total-
 ly different from the disposal method
 envisioned by existing legislation.  Thus,
 it may be necessary to formulate legisla-
 tion that specifically addresses the
 hydrofracture process.

 SUMMARY

    The hydrofracture process has been
 shown to be a viable method for disposal
 of radioactive wastes at ORNL.  The opera-
 tional aspects are routine and could
 rather easily be adapted for hazardous
 waste disposal.  Because the process
 appears to have applicability for hazar-
 dous waste disposal, research needs to be
 conducted on the development of stable
waste forms and carriers, as well  as on
 the rock mechanical  and monitoring
 aspects.  Site selection considerations
 are of prime importance in future appli-
cations of the technology.  There may be a
 need to more fully explore the regulatory
 picture because of the fact that existing
regulations for deep well injection were
not formulated with  the concepts of waste
 isolation that characterize the hydro-
fracture process.
                                         143

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 REFERENCES

 1.  de Laguna, W.,  Tamura,  T.,
    Heeren, H. 0.,  Struxness, E. G.,
    McClain, W. C., and R.  C. Sexton,
    1968, Engineering Development of
    Hydraulic Fracturing as a Method for
    Permanent Disposal  of Radioactive
    Wastes, ORNL-4259,  259  pp.

 2.  Weeren, H. 0.,  Coobs, J. H.,
    Haase, C. S., Sun,  R. J., and
    T. Taraura, 1982,  Disposal of Radio-
    active Wastes by Hydraulic Fracturing,
    ORNl/CF-81/245, 143 pp.

 3.  International Atomic Energy Agency,
    1983, Disposal  of Radioactive Grouts
    1n Hydraulically Fractured Shale,
    Tech. Report Series 232, 111 pp.

 4.  CFR, 1984, Code of  Federal Regula-
    tions, 10 CFR Part  960, Federal
    Register 49 (236),  p. 47717.

 5.  Haase, C. S., Zucker, C. L. and
    S. H. Stow, Geology of  the Host Forma-
    tion for the New Hydraulic Fracturing
    Facility at Oak Ridge National Labora-
    tory, Proceedings of Haste Management
    *85 (in press).

 6.  Haase, C. S. Switek, J., and
    S. H. Stow, 1985, Formation Water
    Chemistry of the  Conasauga Group and
    Rome Formation  near Oak Ridge, Tennes-
    see:  Preliminary Data for Major Ele-
    ments, Geol. Soc. of America Abstracts
    with Programs,  Vol.  16  (p. 94).

7.  Stow, S. H., Haase,  C. S., Switek, J.,
    Holzhausen, S.  R.,  and E. Majer, Moni-
    toring of Surface Deformation and
    Hicroseismicity Applied to Radioactive
    Waste Disposal  by Hydraulic Fracturing
    at Oak Ridge National Laboratory,
    Proceedings of  Waste Management '85
    (1n press).

8.  Holzhausen, G.  R.,  Stow, S. H.,
    Haase, C. S., and 6. Gazonas, Hydrau-
    lic-Fracture Growth  in Anisotropic
    Dipping Strata  as Viewed Through the
    Surface Deformation  Field, Proceedings
    of the 26th U.S. Symposium on Rock
    Mechanics(in press!.

9.  Davis, P.  M., 1983, Surface Deforma-
    tion Associated with a Dipping Hydro-
    fracture,  Jour, of Geophysical
    Research,  Vol. 88, pp. 5826-5834.

10.  Pollard, 0. D., and 6. R. Holzhausen,
    1979, On the Mechanical Interaction
    Between a  Fluid-Filled Fracture and
    the Earth's Surface, Tectonophysics,
    Vol. 53, p. 27-57.

11.  Doe, T. W., and W. C.  McClain, 1984,
    Rock Mechanics Issues  and Research
    Needs in the Disposal  of Wastes in
    Hydraulic  Fractures, Lawrence Berkeley
    Laboratory, LBL-17635, 40 pp.
                  Di sclaimer

 The  work described  In this  paper was
 not  funded  by the U.S.  Environmental
 Protection  Agency.   The contents do
 not  necessarily  reflect the views  of
 the  Agency  and no official  endorse-
 ment should be inferred.
                                       144

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                       DESIGN AND INSTALLATION OF A
GROUND WATER INTERCEPTOR/COLLECTION TRENCH AND TREATMENT SYSTEM

              Frank J. Vernese, Andrew P. Schechter and Thor Helgason
                                 Dames & Moore
                             Horsham, Pennsylvania


                                  ABSTRACT

       This paper  presents a case history of a unique ground water  cutoff wall,
  collection and treatment system  recently approved by the New York State Depart-
  ment of Environmental Conservation (NYSDEC) and the U.S. Environmental Protec-
  tion Agency (USEPA).  The system is designed  to collect and treat ground  water
  contaminated with organics and migrating from a  manufacturing facility in Upstate
  New York.  Construction began in late 1984 and on line testing  is expected to be
  complete by March 1985.

       Characteristics  of the  hydrogeology,  waste and  treatment  system will be
  focused on along  with particular hurdles that had to be overcome  with respect to
  Design and actual construction.  Questions such as:  "how clean is  clean" and "how
  much regulatory involvement can be expected" will be addressed.

  INTRODUCTION  AND PURPOSE         Moore  performed engineering design and
                                          obtained approval by both NYSDEC and
        Early  in 1984, Dames & Moore  was  the   USEPA  in  approximately   nine
  awarded  a  contract  to  provide  engi-  months,
  neering,  design  and  construction man-
  agement  services  to  install  a ground       The purpose  of  the  ground water
  water cutoff wall and treatment system  cutoff  wall and treatment  system is to
  for an industrial client located in upstate  intercept, collect and treat ground water
  M*»w Vra>\f                                  A  •  •        .      .   . °
  «tsw xoiK.                              containing organic  contaminants ranging
       mt_       ^                          up to  1,400  ppb  that  are  migrating
       The  system  was  selected   and  toward the client's property line.   The
  designed by Dames & Moore after com-  primary  contaminants  are   trichloro-
  pletion  of  a  remedial  investigation/  ethylene  (TCE)  and   1,1,1-Trichloro-
  feasibility  study  (RI/FS).   The RI/FS   ethane  (1,1,1-TCE).    The system is
  which  consisted  of borings and ground  approximately 1,800 feet long. It eon-
  water monitoring wells were performed  sists of a main interceptor drain 900  feet
  by   Dames  &  Moore  during  preceding  in iength; a 900-foot  lateral interceptor
  investigations.   Appropriate  laboratory  drain/recharge system,- and  a temporary
  analysis  was  performed  on  selected   organic  treatment system  which  wiU
  ground  water  samples  to  determine   remain  on-line until  the client's  indus-
  plume migration and concentration char-   trial   wastewater  treatment   facility
  actenstics.   Using this data,  Dames <3c  0WTF)  is upgraded to have the capability
                                      145

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of  treating   organics.    A  plot  plan
showing  the  location of the interceptor
trenches,  plume  concentrations  and
direction of ground water  flow  is shown
on Figure 1.

APPROACH

     The  stratigraphy  of the  site  is
generally composed of a silty fine  sand
stratum  varying in thickness from seven
feet to greater than 20 feet, overlying a
gray silty  clay.   Along the northwest
portion of  the site an interbedded layer
of brown  sandy  clay and  gray clay  is
present between  the  silty  fine sand and
the gray silty clay.  Ground water which
is generally  encountered about 10  feet
beneath  the  ground  surface, is flowing
toward the northwest.

     The  main  drain has been aligned
such that  it is situated directly across
the path of contaminated  water  that is
migrating toward the property boundary.
as shown on Figure 1.  The main inter-
ceptor  trench shown  on  Figure 2 has
been keyed into the silty clay unit at the
bottom of  the upper  aquifer.   Figure 3
shows  a  cross section of the trench and
the basic construction of the drain.  The
design includes a 6-inch perforated PVC
pipe in  a bed   of  filter  stone  and a
geotextile  fabric drain that intercepts
the ground water and diverts it  toward
the filter stone and  drainage pipe.  The
fabric  drain  is  sandwiched between a
geotextile  filter   fabric which  extends
around the filter  stone to keep silt and
fines from clogging  the system.  The
advantage  of this unique fabric drain is
that it significantly  reduces the amount
of compacted filter stone required above
the drainage  pipe. It also allows the use
of excavated material as  backfill.  The
alternative, offsite disposal, would  have
been very costly as extensive testing and
transportation to a  secured   landfill
would  be required. The main drain also
includes  five manholes, two of which (at
the  lowest   elevations)  include  sump
pumps to pump the intercepted water to
the temporary treatment plant.

     In addition  to the main drain,  the
system  also includes  a  lateral  inter-
ceptor drain and recharge system, shown
on Figure 4.  It  has been  aligned such
that it runs through the center of  the
plume  along the  axis  of  highest con-
centration  of   contaminated  ground
water.  The purpose of the lateral is to
speed up the  cleanup process by inter-
cepting  the  most  highly  contaminated
water and by recharging clean water into
the aquifer after the aquifer has been
sufficiently  dewatered.     Recharging
clean water in such a manner increases
the  hydraulic  gradient  and  hence  the
flow and velocity of residual contami-
nated water toward the main interceptor
drain where it is collected.   This  in
effect, increases the number of flushings
of the aquifer  to remove residual con-
taminants that may be adhering to soil
particles.  The basic design is the same
as  for  the  main  interceptor  drain.
However, the drain is located a few feet
above  the silty clay unit  and   several
feet below the top of the seasonally high
ground  water table.   As  a  result, no
impermeable liner is required beneath
the drain. This configuration enables it
to serve the dual purpose of draining  the
ground  water when the water table is
high and recharging the   aquifer with
fresh water when the water table drops.
To provide recharge capability, a shutoff
valve is located  in the manhole where
the lateral  has been hooked  up to  the
main interceptor drain.  Additionally, a
metered  connection  was  made to  the
plant's city water line to recharge water
through  a  manhole  into  the  lateral.
Thus, during periods  of low water table
such as the summer months or when  the
aquifer has been  sufficiently dewatered,
the shutoff valve can be  closed and  the
metered connection at  the manhole can
be  turned on, to  permit  recharge  to
enter the soil through the lateral inter-
ceptor/recharge pipe.
                                    146

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     Installation  of  the  interceptor/
collector  pipe required  excavation  to
depths of 15 to 25 feet below grade and
approximately 10 feet below  the  water
table.  Space was limited and, therefore,
a sheeting box  was  used to brace  all
cuts.   Due to the nature of the ground
water, treatment of all dewatering dis-
charge was mandatory.   To accomplish
this,  a  temporary  organic  treatment
system, capable of treating up to 70 gpm
during construction,  was built nearby.
Water  from the  excavation  was pumped
into the system, treated, and discharged
into a local storm sewer.  The treatment
system   consisted   of  seven   Calgon
"Disposorb" units  which contain granu-
lated activated carbon (GAG) connected
in a parallel mode.  Each  Disposorb unit
is capable of  treating up to 10 gpm of
ground water  containing  up to 50 ppm
suspended  solids at  pressures  not  to
exceed 7.5  psig.  This configuration is
shown on Figure  5.  Appropriate pressure
regulators  and volumetric  flow valves
were  also  installed  to  regulate  the
system    within   the    manufacturer's
suggested  range.     Prefiltration   was
achieved  through the use of three bag
filters.  The entire system was enclosed
in a heated structure.

     On occasions  where more than 70
gpm was  encountered in  the deep cut,
tanker trucks  were used,  in addition to
the   temporary   organic    treatment
system, to handle  dewatering discharge.
The trucks would empty their loads into
a holding  tank  at  a nearby industrial
waste treatment facility, which was also
equipped  with GAG units  for organic
treatment.

     Construction proceeded in an uphill
direction  starting with the  lowest  man-
hole, under the continuous inspection of
a   NYSDEC    field   representative.
Periodic    measurements    of   volatile
organies  in the  air within the trenches
were  obtained  by  both  NYSDEC  and
Dames & Moore using a HNU  meter to
insure  that worker  exposure levels were
well below OSHA requirements.   Once
installed,  the  low manhole served as a
sump  point and pumping manhole for
dewatering operations.  The installation
of the pipe involved a seven-part pro-
cess,   including   installation   of  the
sheeting  box,  excavation,  placement of
the impermeable liner and filter fabric,
installation of the pipe and filter stone,
installation of the drainage core, back-
filling  and removal of the sheeting box.
Upon  completion of  the  interceptor/
collector  pipe installation, the  2-inch
force  mains  were   installed  from  the
pumping   manholes  to the   temporary
organic treatment  system.  Permanent
electric  pumps  were  installed  in each
pumping  manhole to pump water to the
treatment  system.    The  interceptor/
collection trench was then operational.

     The temporary treatment  system
will  be terminated once  the  client has
obtained  the capability to treat organies
in  his   industrial   waste   treatment
facility.   NYSDEC  and USEPA required
treatment of the organies  to less than 10
ppb prior to discharge.

     NYSDEC permitted  installation of
the Disposorb units in a  parallel mode
only during construction, since the units
were new and construction was antici-
pated to  extend about three months, well
below  the  time  required for  break-
through.   After  construction, NYSDEC
required  placement of  two  Disposorb
units in a series mode to  provide redun-
dancy  in  case  of breakthrough.  In addi-
tion, after completion of construction,
NYSDEC  required  replacement  of the
three  first-series units prior  to opera-
tion.  As a result, the  system  is capable
of handling 30  gpm as shown on Figure 6.

     The system is  connected to  2-inch
diameter force mains extending from the
two manholes at the lowest elevations to
the bag filters for removal of suspended
solids.   After removal of the suspended
                                    147

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solids, the ground water  passes  through
the Disposorb units for organic removal.
The effluent from the Disposorb units is
then  discharged  to  an industrial waste
line   for  inorganic   treatment  at  the
industrial waste treatment facility.

PROBLEMS ENCOUNTERED

      Originally, construction was antici-
pated to begin in early summer  and the
client's industrial waste treatment facil-
ity capability  to handle  organics  was
anticipated  to  be on line before winter.
However,   delays   in  obtaining   the
required regulatory approvals as well as
delays in completing the organic treat-
ment  capability at the client's industrial
waste treatment facility  necessitated
replanning the construction and opera-
tion  for winter  time.   As a result, a
heated  shed, capable of  containing the
seven  Disposorb   units required  during
construction, had to be constructed.

      Occasionally,  water  infiltration,
through the corners  of the sheeting box
and  into the  excavation,  was  greater
than expected. This  was troublesome in
areas where sands immediately overlying
the clay  were particularly silty.   The
water flowing into the excavation trans-
ported silt,  so  that both dredging of the
silt  and  pumping  of the water  were
necessary prior to any pipe installation.
In addition, during construction the high
silt content periodically clogged the bag
filters,  necessitating  replacement of the
filter bags.

      The  process   of   installing   the
sheeting box, pipe and associated  filter
fabric and  drainage core  was  initially
very  time consuming, especially in the
deep    sections   of   the   alignment.
However, once the Contractor delegated
specific responsibilities  to  the  crew,
efficiency dramatically increased.
RESULTS

     Preliminary   monitoring  of  the
influent and  effluent entering the tem-
porary treatment  facility indicates  that
total  VOA's  exceeding 300 ppb  which
enter the  Disposorb units  are reduced
to  1 ppb in the effluent.

     During   operation,  influent  and
effluent  monitoring of each  series of
GAG units  will be performed on a weekly
basis  to  insure that breakthrough  does
not occur.
                 Disclaimer

  The work described in this  paper was
  not funded  by the U.S. Environmental
  Protection  Agency.  The contents do
  not necessarily reflect the views of
  the Agency  and no official  endorse-
  ment should be inferred.
                                     148

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                                                           202

INTERCEPTOR/COLLECTION  TRENCH LOCATION
                    TOTAL PRIORITY POLLUTANTS
                   VOLATILE HYDROCARBONS (PPB)
                     GLACIOFLUVIAL AQUIFER
                             JUNE 1984
                APPROXIMATE GROUND WATER FLOW DIRECTION
                APPROXIMATE LOCATION OF INTERCEPTOR TRENCH
               ] BELOW DETECTION LIMIT   |^p^*|| 1000 TO 1700 PPB
               | 3 PPB TO 100 PPB             1700 TO 2100 PPB
               I: TOO TO  1000 PPB

                                FIGURE 1
                                   149

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                            UiJ Mi BOUVAJ1!

                         §       s       8
IM-t — • -
                                                                              UJ
                                                                              oc
                                  150

-------
EXISTING GROUND
    SURFACE
                          RESTORE EXCAVATED AREA TO ORIGINAL CONDITION
    < z
    -1 UJ
    0 UJ
    I- UJ
    -i eo
    < ee
          SANDY FILL AND
           BROWN SAND,
           SILTY SAND
           AND GRAVEL
TRENCH EXCAVATION
SIDE  SLOPE MAY
NEED  SHEETING
AND BRACING
SUPPORT WHERE
NECESSARY OR
REQUIRED
                                  .COMPACTED
                                   BACKFILL
COMPACTED FILTER
STONES TO 12 IN.
   ABOVE PILE
                                                                               CORE
                                             TRENCH
                                             EXCAVATION
                                             SIDE SLOPE
                                                                 IN. DIA. PVC SCHEDULE
                                                         . *1« .••*•.'•	,'  »••,•«•
                                                          "f-f ,.„.«,,..«...««   .' '
                                                        ^S=3S^J^?^>^^//^Ii^^
   SILTY CLAY
       MIN. 6 INCHES-
       TRENCH PENETRATION
       INTO NATURAL SILTY
       CLAY SOIL
                                              2'~6"
                                                        "^IMPERMEABLE  LINER
                             DRAIN CROSS  SECTION
                                     ( NOT TO SCALE )
                                          FIGURE 3

-------
                                                 oc
                                                 cs
1114 Nt NOUVA)!]
             152

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       ELEVATED SPACE
          HEATER
en
        HEATED BLDG,
        TO HOUSE TTS
                                                CONFIGURATION
                                            DURING CONSTRUCTION
                                                                       EFFLUENT
                                                                     (UP TO kQ GPM)
ELEVATED SPACE
 HEATER
                                                                                            BAG FILTER (TYP)
                                                                                             INFLUENT
                                                                                            SPARE BAG FILTER
                    NOTES:
                    1. 7 CALGON DISPOSORB UNITS (10 GPM TREATMENT CAPACITY EACH)  WILL BE CONNECTED IN 2 CLUSTERS
                      OF 3 AND k UNITS EACH FOR OPERATION DURING CONSTRUCTION.
                    2. ROSEDALE OR SIMILAR BAG FILTER WILL BE USED TO REMOVE SUSPENDED SOLIDS TO 0.5 MICRONS.

                    3- © DENOTES AVAILABLE SAMPLING POINTS,
                             TEMPORARY TREATMENT SYSTEM  (TTS)

                                                     FIGURE 5

-------
en
         ELEVATED SPACE
            HEATER
          HEATED BLDG.
         TO HOUSE TTS
                                                  CONFIGURATION
                                               POST CONSTRUCTION
 ELEVATED SPACE
  HEATER
                                                                                             SPARE DiSPOSORB UNIT
SPARE BAG FILTER


BAG FILTER(TYP)

INFLUENT



SPARE BAG FILTER
                      NOTES:
                      1. 6 CALGON DISPOSORB UNITS (10 GPM TREATMENT CAPACITY EACH) WILL BE CONNECTED IN 3 SERIES
                        OF 2 UNITS EACH FOR OPERATION AFTER CONSTRUCTION.
                      2. ROSEDALE OR SIMILAR BAG FILTER WILL BE USED TO REMOVE SUSPENDED SOLIDS TO 0.5 MICRONS.

                      3- ff^ DENOTES AVAILABLE SAMPLING POINTS.
                              TEMPORARY TREATMENT SYSTEM   (TTS)

                                                      FIGURE 6

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       MICROBIAL DETOXIFICATION OP CYANIDE PROM WASTEWATBR

                  N.  Shivaraman and N.M,  Parhad

     National Environmental Engineering Research Institute,
                  Nehru Marg,  Nagpur 440020 (India)

                             ABSTRACT

      Industrial wastewatar containing cyanide must be treated bef-
 ore discharging into the environment as it is toxic to mammalian
 and aquatic life.  Though alkaline chlorination process (chemical)
 is generally advocated, biological methods - comparatively cheap-
 er, can be tried for cyanide removal.  Biodegradation of alkali
 cyanide in acclimated trickling filter and activated sludge pro-
 cess as well as by pure microbial isolates have been reported in
 literature.  The paper deals with the work carried out in labora-
 tory model continuously fed complete mixing aeration system - see-
 ded with cyanide acclimated microbial sludge, on following asp-
 ects - (i) Microbial detoxification of cyanide, (ii) Influence of
 zinc, copper and cadmium on cyanide biodegradation and (iii) Pea-
 sibility studies for cyanide removal in wastewater from a gold
 ore processing system.

      The biological system was operated at a hydraulic detention
 time of 12^1 hr.  The experimental results revealed that (i) Cya-
 nide could be degraded effectively at cyanide loading of 0.130 -
 0.131 g CN""/g MLSS/day and the effluent had less than 0.2 mg/1
 CN~.  Assay of bioreactor MLSS for microbial counts showed that
 cyanide resistant counts were more or less same with peptone and
 sewage - 2.8x10 /ml and the total viable counts were 7.8xl07 and
 S.OxlO/ml respectively, (ii)  Zinc at 50 mg/1 and cadmium below
 20 mg/1 did not affect cyanide biodegradation while copper even
 at 5 mg/1 affected cyanide removal,  (iii) Cyanide present in the
 gold ore processing wastewater could be removed to the extent of
 79 to 87 percent and  (iv)  there was  significant removal of the
 metals during the treatment and were found to be associated with
 MLSS.

INTRODUCTION AND PURPOSE            waste waters like plating mill
                                    and gold ore processing, cya-
     Treatment of cyanide con-      nide also occurs as heavy me-
taining waste waters is an im-      tal complexes.  Generally alk-
portant concern in industries       aline chlorination is the met-
where it is used or produced.       hod of choice for cyanide des-
This is because cyanide is hi-      truction.  However, biological
ghly toxic to mammalian and         treatment systems which would
aquatic life.  In certain           be comparatively cheaper, have

                               155

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been investigated by several
workers.  Biodegradation of
simple alkali cyanide in acti-
vated sludge process (1-4) and
both simple and heavy metal
complex cyanide in trickling
filters (5-7)have been inves-
tigated.  It has been found
by these investigators 'that
simple cyanide can be degra-
ded by these processes after
acclimation.  However, though
zinc and cadmium cyanide com-
plexes were found to be deg-
raded by acclimated trickling
filters,copper and iron com-
plexes were found to be poor-
ly removed (7).  Further the
extent of influence of heavy
metals on cyanide biodegra-
dation in a completely mixed
aeration system (CMAS) as well
as studies on amenability of
cyanide biodegradation in go-
ld ore processing waste water
appears to have not been ca-
rried out.

     The purpose of this inve-
stigation was to establish the
biodegradation of alkali cya-
nide by the specific microbi-
al sludge developed in this
laboratory in a CMAS and to
find the influence of zinc,
cadmium and copper on cyanide
biodegradation as well as to
study the feasibility of bio-
logical removal of cyanide
from gold ore processing was-
te water which also contained
heavy metals like zinc and
copper in significant concen-
trations.

APPROACH

Bench Model CMAS

     Studies were carried out
to find the biodegradation of
cyanide by continuous feeding
experiments.  A bench model
CMAS consisting of an aeration
unit of two litre working vol-
ume with a built-in settling
chamber was used for the study.
The cyanide containing waste
water was placed in a reserv-
oir and fed to the aeration
unit by either a solution met-
ering or electrolytic feeding
pump.  A line diagram of the
assemblege is given in Figure
1.  Compressed air was suppli-
ed for aeration.  Microbial
sludge was developed in the
aeration unit with synthetic
cyanide waste containing pep-
tone/domestic sewage as orga-
nic nutrients.  The unit was
also seeded with a cyanide
                   Influent
                   3  4
             Air
                         -Effluent
Figure 1. Bench Model diagram
          of CMAS.
          1-Feed Reservoir;
          2-Feeding Pump;
          3-Aeration Chamber;
          4-Built-in settling
            Chamber.

degrading organism Pseudomonas
acidovorans which was isolated
in this laboratory* The  system
was put to continuous operat-
ion after building up the mic-
robial sludge to around  1000
mg/1 as mixed liquor suspend-
ed solids (MLSS) .
                              156

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Preparation of Waste Water

     In all these experiments
either peptone (50 mg/l) or
settled domestic sewage(l hr
settling) was used as organic
nutrients.  Water of following
composition was used for pre-
paration of synthetic cyanide
waste - sodium bicarbonate 250
mg; potassium dihydrogen orth-
ophosphate 50 mg; magnesium
sulphate 50 mg; calcium chlo-
ride 20 mg; ferric chloride
1 mg and distilled water one
litre.  Settled sewage was
mixed with synthetic cyanide
waste in equal proportions
(V/V) for the experiments on
biodegradation of alkali cya-
nide.  For studies on influ-
ence of heavy metals peptone
was incorporated in the syn-
thetic cyanide waste. The cya-
nide concentration was kept
more or less constant and the
metal's concentrstions were
varied.  The metals were tes-
ted individually and added to
the synthetic waste as  their
sulphates after the addition
of cyanide so as to avoid
their precipitation.  In fea-
sibility studies with gold
ore processing waste waters
the sewage was mixed with the
waste water at 1$ 3 proportion
(V/V).

Source of Gold Ore Processing
Waste Water

     The benefication of cru-
shed ore results in the sepa-
ration of gold and waste rock
known as tailings.  The gold
from fine ore which may not
settle in the gravity separa-
tion process is taken to cya-
nidation plant for oroper dis-
solution of gold. Sodium cya-
nide is used as transfer agent.
Process waste water is disch-
arged from cyanidation plant,
vaccum filter,  zinc extraction
boxes and from acid vats. The
waste water from the processes
is collected in the residue
tank and pumped to a series of
dump pits in the tailing site.
The settled waste water from
the residue tank (after sett-
ling the tail ings)was collected
for the studies.

S amp 1 ing and Analysis

     The CMAS was operated at
hydraulic detention time of ar-
ound 12+1 hr.  Random samples
were collected after the sys-
tem reached steady state and
subjected to analysis.  The
analytical methods adopted for
cyanide, metals, biochemical
oxygen demand (BOD)» chemical
oxygen demand (COD) and MLSS
were as per the procedures giv-
en in Standard MethodsfS) . The
heavy metals were determined
by Atomic absorption spectro-
photometer.  The microbial as-
say of the reactor contents
for total viable and cyanide
resistant counts were carried
out as per the procedure given
in our earlier paper(4).  The
pH was determined with pH met-
er.  In tables cyanide and he-
avy metals are expressed as
CN~ and as individual metal
respectively.

RESULTS

Biodegradation of Simple Cyanide

     The CMAS was operated with
                               157

-------
 synthetic cyanide waste, first
 containing peptone and later
 with sewage.  The BOD and CCD
 of the sewage used in this
 study were 158 and 279 mg/1
 respectively and they were
 estimated to only know the
 organic content of the same.
 Cyanide in influent and eff-
 luent as well as MLSS of the
 bioreactor (Aeration unit)
 were estimated.  The results
 are presented in Table 1. The
 cyanide loading with peptone
 and sewage were worked out to
 be 0.131 and 0.130 g CN~/g
 MLSS/day respectively. It cou-
 ld be seen that cyanide could

  TABLE 1. BIQDEGRADATION OF
           CYANIDE IN CMAS
Parameter
              Peptone Sewage
                11
91.10
6.92
0.02
N.C.
99.97
115.50
14.70
0.18
0.02
99.84
No. of obser.

Cyanide, mg/1
  Influent AM
           SD
  Effluent AM
           SD
  % Reduction

MLSS,mg/1
           AM 1390.00 1766.00
           SD  106.80  318.80


  Influent    9.1-9.4 9.1-9.4
  Effluent    8.9-9.0 8.7-8.9

 N.B. AM = Arithmetic Mean,
      SD = Standard Deviation,
      NC = Not Calculated.

 be degraded by  the microbial
 flora  and there was more  th-
 an 99  percent reduction.  The
 microbial status of the bio-
 reactor MLSS were assayed
 and the results are presented
                                    in Table 2.  Tha presence of
                                    cyanide resistant counts fur-
                                    ther confirms the cyanide met-
                                    abolism in the system and the

                                     TABLE 2. MICROBIAL STATUS OF
                                              CMAS.
Parameter
No. of obser.
T V C per ml
Minimum
Maximum
A. Mean
C R C per ml
Minimum
Maximum
A. Mean
Peptone
6
5.8x107.
9.7x104
7.8xlO~
4.6x10^
4.6x104
2. 8x10 '
Sewage
5
2.4x10®
3.8x10®
SlOxlO8
9.0K106.
4.6x104
2.8xl07
N.B. TVC = Total Viable Count,
     CRC = Cyanide Resistant
           Count.

counts were more or less same
in both the experiments(with
peptone as well as sewage) *
The total viable counts were
more with sewage as compared
to peptone.  This could pro-
bably be due to the inherent
flora of sewage which might
have proliferated uninhibited.
The microbial status also ind-
icated that there were more
satellite organisms present in
the system other than cyanide
resistant ones as the total
viable count was more than the
cyanide resistant count.

Influence of Heavy Metal sm_

     The most common heavy
metals that occur with cyani-
de  in certain wastes are zinc,
cadmium, copper and iron. Sin-
ce  complex iron cyanide has
                                158

-------
indicating that cyanide foiode-
gradation by the microbial sl-
udge was severely affected by
cadmium at this concentration.
  1201-
                INFLUEHT CM
               8   10  12 14
               CYCLES-*-

Figure 2. Influence of 50 rng/1
          Cadmium on cyanide
          degradation.

     The pH of the influent
and effluent were also recor-
ded and were in the range of
8.8 to 9.3 and 8.6 to 8.8 res-
pectively.  The results of the
analysis of the MLSS  for the
metals at one of the  influent
concentrations for each metal
are given in Table 4.

 TABLE 4. DEMONSTRATION OF
          METALS IN SLUDGE
Metals Influent
(mg/1)
Zinc
Cadmium
Copper
25
5
5
Sludge
(mg/g MLSS)
217.50
4.85
1.34
     The metals zinc and cad-
mium are found to be associa-
ted more with the MLSS than
copper.  This is also refle-
cted at the lower concentra-
tion of zinc and cadmium in
the effluent and also at poor
removal of copper  (Table 3).
Once the cyanide is degraded,
the alkaline pH of the conte-
nts could have favoured pre-
cipitation of zinc and cad-
mium and hence they would have
appeared in the MLSS.  Cheng
et»,al(9) while studying the
effect of pH on the removal of
heavy metals in the activated
sludge process, have reported
that considerable precipita-
tion of metal hydroxides could
take place at high pH.

Studies with Gold Ore Proce-
ssingWaste

     The waste water was coll-
ected twice from the site. The
characteristics of the waste
are given in Table 5.  The cya-
nide was 24 and 34 mg/1 and the
waste also showed the presence
of copper and zinc in signifi-
cant concentrations.  Presence
of zinc in the waste was due to
its use in gold extraction pro-
cess.  The higher value of zinc
in sample 2 was due to a disch-
arge from acid vat at that time
of collection.  Sample 1 and 2
were used for peptone and. sewa-
ge supDlementation studies res-
pectively.  The BOD and COD of

 TABLE 5. CHARACTERISTICS OF
          THE WASTE WATER

Parameter     Sample 1 Sample 2
Cyanide, mg/1
C.O.D.,
2inc,
Copper,
Iron,
P«
mg/1
mg/1
mg/1
mg/1

24.00
286.00
7.85
8.39
0.38
7.20
34.00
438.00
46.00
12.90
0.45
7.50
                                159

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TABLE 3. INFLUENCE OF HEAVY METALS ON CYANIDE BIODEGRADATION
Metal (No.
of obser-
vations)
Zinc (8)
(8)
(8)
Cadmium (9)
(5)
(5)
Copper (7)
(6)
(6)
Metal
Infl
uent
10
25
50
5
10
20
5
10
20
Cone. mg/1
Effluent
MeantS.D.)
0.07(N.C.)
0.04(N.C.)
0.12(0.19)
0.13(0.02)
0.60<0.50)
0.56(0.09)
4.06(1.28)
8.50(0.56)
17.60(1.00)
Cyanide as
Influent
Mean(s.b.)
98,6(6.63)
97.4(2.67)
98.2(6.96)
95.6(3.50)
97.4(7.00)
100.0(0.76)
96.7(2.45)
96.1(2.00)
97.0(1.00)
CN, mq/1
affluent
Mean(S.D.)
0.20(0.01)
0.18(0.01)
0.19(0.02)
0.17(0.02)
0.18(0.02)
0.18(0.01)
2.00(0.40)
16.20(3.60)
28.50(2.00)
MLSS mg/1
Mean(S.D.)
1080 ( 70.4)
1370(173.4)
2175(336.0)
1645(148.8)
1490 ( 41.8)
1430 ( 41.8)
1064( 55.6)
1025 ( 68.9)
82-5 ( 68.9)
  N.B.  SD = Standard Deviation? NC = Not Calculated
been reported to be more  ref-
ractory to biodegradation(7)
the studies were restricted
to zinc, cadmium and copper.
The concentrations tested were
upto 50 mg/1 in the case  of
zinc and cadmium, and  20  mg/1
in case of copper.  The con-
centration intervals were,
however, selected arbitra-
rily.  A known concentration
of the metals (pre-estimated
in the stock solution) were
added to the synthetic waste
and hence the influent was
not analysed for the metals.
The cyanide in the influent
and effluent, the metals  in
the effluent and the MLSS of
the bio re actor were estimated.
The results are presented in
Table 3.  It could be  seen
that zinc upto 50 mg/1 and
cadmium upto 20 mg/1 did  not
influence cyanide removal and
the effluent showed less  than
0.2 mg/1.  However, copper
even at 5 mg/1 showed  compa-
ratively less removal  of  cya-
nide and its removal deteri-
orated with increasing copper
concentration.  Pettet and
Mil is (7) also found that the
acclimated biofilter was not
able to effectively remove cya-
nide from the waste containing
alkali copper cyanide complex.
However, they found effective
cyanide removal when fed with
zinc and cadmium alkali cyanide
waste.  They attributed the in-
effective removal of cyanide in
presence of copper as due to
more stable complex copper wou-
ld be forming with cyanide.

     The results of effect of
cadmium at 50 mg/1 is given in
Figure 2.  The cyanide in the
influent and effluent are sho-
wn in it.  The CMAS was working
at 20 mg/1 of cadmium in the
influent initially.  At the
point indicated in the figure
with an arrow. Cadmium in the
influent was  raised to 50 mg/1.
One cycle shown in the figure
is equivalent to two litres
of waste fed  in 12 hrs.  It
could be seen that at 50 mg/1,
the effluent  quality with res-
 pect to cyanide deteriorated
                              160

-------
the sewage   — 74 and 270 mg/1
respectively, were determined
only to know the organic load
of the same.

     Cyanide and the metals
in the influent and effluent
as well as MLSS in the biore-
actor were estimated.  The
results are presented in
Table 6.  The average MLSS in
the bioreactor with peptone
and sewage were 960  (SD =153)
and 2168 (SD= 503) mg/1 res-
pectively.

TABLE 6. PERCENTAGE REDUCTION
        OF CYANIDE & MSTALS
Parameter
Peptone   Sewage
Cyanide, mg/1
  Influent AM
           SD
  Effluent AM
           SD
  %Reduction

Zinc, mg/1
  Influent AM
           SD
  Effluent AM
           SD
  %Reduction

Copper, mg/1
  Influent AM
           SD
  Effluent AM
           SD
  %Reduction

Iron, mg/1
  Influent AM
           SD
  Effluent AM
           SD
  ^Reduction
  21.50
   0.86
   2.80
   1.28
  87.00
21.20
 4.20
 4.40
 1.87
79.24
7.60
0.13
2.20
0.66
71.05
31.00
15.16
4.08
5.69
86.84
7.04
0.61
3.93
1.53
44.18
9.48
0.76
3.37
1.94
64.45
0.43
0.08
0.37
0.07
13.95
0.43
0.06
0.28
0.11
34.88
pH
   Influent
   Effluent
7.1-7.2 7.4-7.5
7.6-7.8 8.4-8.6
N.B.  The values are Arithmet-
      ic Mean (AM) of 7 obser-
      vations,
      SD = Standard Deviation.

     The results obtained sho-
wed that the cyanide in the
waste water was amenable for
biodegradation. However, the
removal of cyanide was not to
the extent that was obtained
with simple alkali cyanide
(Table 1) or with zinc alkali
cyanide complex (Table 3).
This could be due to the pre-
sence of copper(ineffective
removal of cyanide in presence
of copper -Table 3) as well as
iron.

     The mixed liquor suspen-
ded solids were also assayed
for the metals on three occa-
sions during each exoeriment.
The results showed that zinc,
copper and iron were found to
be with the solids and were in
the range of 35.2 to 107.1,
2.4 to 22.2 and 1.1 to 4.5 mg/g
suspended solids respectively.
The zinc content was found to
be more as compared to other
metals.

     From these studies follow-
ing conclusion can be made -
(i) Biodegradation of simple
 alkali cyanide could be eff-
 ectively brought about in the
 biological system with the
 acclimated microbial sludge,
(ii> Zinc upto 50 mg/1 and cad-
 mium up to 20 mg/1 did not in-
 fluence cyanide biodegradation.
  However, copper even at 5 rag/
 1 affected effective removal
 of cyanide,(iii) Though cya-
 nide present in the gold ore
 processing waste could be bio-
 logically  degraded to a sig-
                               161

-------
nificsnt level  (79.24 to 87.0
percent reduction), its removal
to the extent desired(less th-
an 0.2 mg/1) was  not obtained.
This limitation hes to be tak-
en into account before sugges-
ting a biological  treatment
system for  gold ore processing
waste water and  (iv)  During the
treatment of waste waters,  the
metals were found  to be asso-
ciated with the KLSS.   Their
continuous  emergence in the
bioreactor  can also result in
the retardation of microbial
activity on a long term basis.

ACKNOWLEDGEMENT

     The authors  are thankful
to the Director,  National Env-
ironmental  3ngineering Resea-
rch Institute, Nagpur -20,
(India) for his encouragement
and permission to  present this
work.  They are also thankful
to (Late)Prof. V.  Raman,Deputy
Director and Shri S,D,.Badrina-
th. Scientist,N2SRI,Nagpur for
their help.  The  authors also
wish to record their thanks
to Mr.R.A.Pandey  and K^ss S.K.
Chatterjee  for rendering help
in some analysis.

RSFSREtiCSS

1. Ludzack,P.J.and Schaffer, R.
   B.,1960,  Activated sludge
   Treatment of Cyanide,Cyana-
   te and Thioeyanate. Proc.
   15th Ind.Waste Conf»,Purdue
   University,Lafayette India-
   na, pp.439-460.     '

2. Murphy, R.B. and  Nesbitt,J.B.
   1963, Aerobic  metabolism of
   cyanogenic compounds.Report
   on Project WP-OQ151-04,Dept.
   of Civil Sngg., Sanitary
       2ngg. Laboratories,College of
       3ngg.,The Pennsylvania State
       Uni.,University Park,Pennsy-
       lvania.

    3.  Gaudy, A. F., Jr., Gaudy, 5. T.,
       Feng,Y.J. & 3rueggemann,G,
       1982. Treatment of cyanide
       waste by the extended aera-
       tion process. Journal,WPCF
       Vol.54,No.2, pp 153-164.

    4.  Shivaraman,N. and Parhad,N.M,
       1984. Biodegradation of cya-
       nide in a continuously fed
       aerobic system. Jou realfEnyi-
       ronmental Biology, Vol.5,
       No.4, pp 273-284.

    5.  Gurnham,C.P., 1955. Cyanide
       destruction on trickling  fil-
       ters. Proc.J.Ot h Ind.Waste Conf.
       Purdus University,Lafayette,
       Indiana, pp. 186-193.

    6.  Winter,J.A.,1962. The use of
       a specific actinomycete to
       degrade cyanide wastes. Proc,
       17th Ipd.Waste Conf.,Purdue •
       University, Lafayette,Indiana,
       op.'703-716.

    7.  Pettet, A.E.J.and Mills,S.V.,
       1954. Biological treatment
       of cyanides, with  and without
       sewage, J.Appl.Chem,,Vol.4
       pp. 434-444.
    8. APHA, AW',1 A  and WPCF.  Stand-
       _ard'methods  for  the  examina-
       tion ofwaterand  waste  wa-
       ter. 13th Sd. APHA,  Inc.,
       New York, 1971.
    9. Cheng,M.H.;  Patterson, J.W.
       & Minear, R.A.,1975.  Heavy
       metals uptake by activated
       sludge. Journal  WPCF,  Vol.
       47, No.1, DD. 362-376.
                 Di sclaimer

      The work described in this paper  was
      not funded by the U.S. Environmental
      Protection Agency.  The contents  do
      not necessarily reflect the views of
      the Agency and no official endorse-
162    ment should be inferred.

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            REVIEW OF CURRENT PRACTICES FOR REMOVAL AND DISPOSAL
                   OF ARSENIC AND ITS  COMPOUNDS IN JAPAN

                  H,  Kawashima, D.  M.  Misic and M. Suzuki
            Institute of  Industrial  Science, University of Tokyo
                               Tokyo, Japan
                                 ABSTRACT
    Wastes  containing  arsenic  are generated  not only during production of
arsenic  and  its  compounds,  but also  from  production  of  non-ferrous  metals,
non-metals (phosphorus,  fertilizers,  etc.),  geothermal power generation, elec
tronic industry processes, and large-scale
preservatives.  Liquid and gaseous waste
their hazardous  nature,  must be  treated
environment.
    applications of pesticides and wood
    streams  containing arsenic,  due to
    before they are released into the
    A flowsheet briefly summarizing qualities  and uses of arsenic and its
compounds  in Japan  is presented.  At the  present  time  there are no visible
undersirable effects of  the treatment and disposal methods currently  practiced
in Japan.  Some specific treatment and disposal methods are  described.
INTRODUCTION

    Arsenic and arsenic compounds
are  used  for  many  different
applications such as:   insecticides,
herbicides,  dessicants,  rodent
control,  and  animal  food  additives.
When swallowed,  all  of them  cause
acute poisoning;  chronic  poisoning
could also result from inhalation
(1).   Besides their  toxic  nature,
arsenic  and its  compounds  are also
explosive  and  ignitable,   and
therefore  they  are classified  as
hazardous  materials.   The wastes
obtained  from  production of arsenic
and  its   compounds,   from mining
operations, from  production on non-
ferrous   metals,   non-metals
(phosphorus, fertilizers etc.), from
electronic industry  sources, from
sludge  treatment,  and  from
combustion  (2)  are treated  as
hazardous  metals.
Flow  of Arsenic (Figure 1).
              large amount  of
               was  imported  to
Until recently
arsenic  (as  As
Japan from France, the USSR,  and  the
People's Republic  of China.    Arsenic
coming  from China  was rather of  low
quality,  but inexpensive (approximately
¥200/kg).  During 1984 no arsenic  was
imported to Japan.   Most of the arsenic
currently comes from copper refineries
in the form of AS2S3, which is converted
to  As^Og.   There  are  three  major
companies  which   handle  nearly  100
percent  of  arsenic  production  -
Furukawa, Sumitomo  and  Onahama.  Annual
production  of AsoOj is approximately 865
tons/year.    rrom this  quantity
approximately  200  tons/year of high
quality  product  (approximately  ¥400-
500/kg)  are exported to  South-East Asia,
Australia and America.  Distribution of
the remaining  production is as follows:
300t/y   is  used  for  production   of
pesticides,  wood-treatment  agents,
animal  food additives, etc.; 200 is used
in zinc  refineries;  150  is used in glass
production; 15 is used for production of
arsenic   in   metal  form  used   in
semiconductor  industry.   The  above
numbers  represent  only  the  approximate
distribution  of   the  A s £ 0 3  amon9
                                   163

-------
different industries.   About  1   of
arsine (AsHo)  is  imported  from  the
United  States for  production  of
semiconductors.   Part of  the zinc
refineries' wastes  containing high
concentrations   of arsenic  are
returned to the manufacturers (3).

    The manufacturers  of As20o,  as
well  as  the  other  users or  the
product,   use  conventional  chemical
precipitation,   coagulation,  and
sedimentation processes to  obtain
sludges  which are  taken  to land
disposal  or used for  reclaiming land
from  Tokyo Bay.  The semiconductor
Industry  also  uses  a  special
adsorption process (TOXO-CLEAN)  and
these  wastes are  stored in  old
mines.  Another source  of arsenic is
geothermal power  generation.   Most
of this arsenic is removed  by  preci-
pitation-sedimentation treatment,
while some small  quantities  in  low
concentrations are released directly
into the environment.  Pesticides
and wood-decay prevention agents are
directly released  into the environ-
ment.  Land disposal  also contri-
butes to the direct environmental
discharge.

TREATMENT

    Most treatment processes include
chemical  precipitation  and
separation   of   solids   by
sedimentation.   Obtained sludges are
sometimes further treated  for safe
final  disposal.   A  few  of  the
current practices,  including some
details,  will  be presented  here.

    Treatment of water  in a geo-
thermal power  generation plant.  The
processes  presented  here  are
employed by Kyushu Electric Company
at their Ohdake,  Hachiogahara Plant
in  Ohita Prefecture,  Kyusha  (4).
The   water  and steam  from  a
geothermal  well   enter a separator.
Steam  goes to turbines while  the
separated  water  enters a holding
tank.  A  portion   of  the  water  is
returned to the  underground  well,
while  the  rest of the water is pumped
into a  reactor where  150 nr/hr.  of  water
are  treated.  The  water entering  the
reactor  has  approximately 2-3 ppm of
arsenic  with a  pH  of  7.5-8.5.   This
water  is mixed  with 3.9 //h  of  70%
sulfuric  acid (H2S04),   14.9  iyhr of
NaOCl (containing 7% C12)  and  10£/hr of
FeClo  solution (containing 13% of Fe).
The pll  value in the reactor is between 3
and  4.   The reactor effluent enters a
mixing  tank where NaOH (22%) solution is
added and the  pH is raised to between 4
and  4.5.   The slurry  from the mixing
tank goes  into a filter press.    The
solids  are  taken by conveyor belts  into
storage,  from  where they are transported
to final  disposal sites.   Production of
solids  is  approximately  1.5 m3/day.
Depending on the concentration of
arsenic,  the  filtrate  may be  stored in
the  liquid  waste  storage tank   and
recycled to the head of the treatment
processes, or treated with NaOH solution
(22%) so  that  the pH value is raised to
5.8-8.6.  Arsenic concentration in  the
treated  water is  below 0.05 ppm,  and
this water is directly released to  the
environment.  Cost for this treatment is
approximately  ¥150/m3  (approximate  U.S.
$0.60).

    The  chemistry  of  this  process
basically  is  given  by the following
equations:
AsO3"  + NaClO
   3"
        Fe
         3+
AsO
FeAs0
       NaCl
    Ferric arsenate is little soluble in
pH range of 5-8.  The  schematic flow
chart of the  process  is presented in
Figure  2.

    Treatmentof wastewater containing
arsenic  and _ gall urn  from semi-conductor
production.   Nippon Electric  Company
(NEC)has  developed  a  process  for
removing  arsenic  and  recovering
expensive galiurn  from  wastewater in a
Ga-As semiconductor  production plant
(5).     The    process   involves
coprecipitation of arsenic and galium by
Fe(OH)3 (addition of FeCl3 and  NH4OH) at
                                  164

-------
pH values below 7,   The precipitate,
separated from the supernatant by
filtration, is suspended in water
and NaOH is added to raise  pH  above
9  (usually  to  approximately 13) to
redissolve  galium.  The  arsenic
remains in solid form and is removed
by  filtration.    The  removal  of
arsenic is above 95%.  The separated
sludge containing arsenic,  is  taken
to a solid waste disposal site.

    For  example,  to a  wastewater
containing 10 ppm As and  10 ppm  Ga,
100 ppm of  Fe(III) was  added and
mixed with aqueous NH^QH to  raise
the pH to  5.2.  The coprecipitate,
after separation,  was  suspended in
water and  mixed  with NaOH  to  raise
the pH to 13.   Arsenic concentration
remaining in the solution containing
galium was below 0.5 ppm.

    Treatment   of   wastewater
containing  arsenic from  cadmium
refining.  Nippon Mining Corporation
has a patent for removal  of arsenic
from low pH wastewaters (6).   The
process  is  most efficient when  the
pH is between  1 and 2.5, and  it is
recommended only  for pH below  3.
The treatment utilizes dialkyl  thio-
carbamate as a chelating agent.  The
alky! group (R) can be methyl,  ethyl
or n-bentyl.  The compound makes
metal   (Me)   complexes  of  the
following form:
    R
          N - C -  S],
Me
which are precipitated.  For removal
of arsenic from  cadmium refining
wastes RoNCSSNa was used.  The usual
ratio or dialkyl  thiocarbamate to
arsenic ranges from 1 to  5.  The
wastewater  was  mixed   with
approximately  1  equivalent  of
dialkyl thiocarbamate at 400 RPM for
30 minutes at different pH values.
Best  results are   achieved  with
dimethyl carbamate at approximate pH
value  of  1.1.   More  than  95% of
arsenic  is removed.  The precipitate  is
incinerated and arsenic is  recovered.
There are no disposal  problems  related
to this  process.

    Removal of arsenic  from wastewater
by use of syntheticresins. Unitika
Ltd.,  a  large manufacturer  of snythetic
fibers,   has  a  patent  for  removal  of
arsenic  from  wastewaters  having low
concentrations   of  arsenic   (like
geothermal  waters  with  2-3 mg/)L)(7).  A
chelating  resin  containing CHoN=(R)
CH2[CH(OH)]n CH2OH  moiety, where  R  is H
or C|_5  alky! and £ is 1 to  6,  is used.
The adsorption capacity for Amber!ite
IRA 743 was 30 mg AsJ /ml of  resin.

    Treatment  of  arsenic  containing
wastewaters  withtitanium   compounds.
Mitsubishi Rayon has developed a  process
for removal of arsenic  from  wastewaters
that  contain several  metal  ions  (8).
The process is used by the electronic
industry.   Wastewaters  containing
arsenic  are  treated with  a titanium
compound  (Ti[OCH(CH3)2]4) to  form
titanic  acid,   which   forms  a
coprecipitate  with  arsenic.   In  a
wastewater initially  containing  97mg/L
of  arsenic,  the  concentration after
coprecipitation  and  filtration  was
reduced  to  0.026-0.054  mg/L.   The
process   is most effective  in  the  pH
range between  2 and  8.    The   only
disadvantage is  that the  process  is
rather  lengthy -  16  hours.   Other
titanium  compounds  could be  used,  like
TC14 or  TiOS04.

    Adsorption of arsenicby red  mud.  A
very  low cost process  for  removal of
arsenic  was  developed  by the Agency  of
Industrial  Sciences and Technology (9).
Red  mud,  obtained  from  aluminum
production,   usually  contains
approximately 17-25% of A1203, 25-50%  of
Fe203 and  5-20% of Si02.   A1203 and
Fe203 adsorb arsenic.  In the pri range
between 5 and 7  removal efficiency  is
over  99%.   Wastewater  containing
aresenic  is shaken with red mud  for  24
hours.   The red  mud could be shaken  in
0.01 N sodium hydroxide for 24  hours,
separated and reused. The main advantage
                                 165

-------
of the process  is its low cost.

    Treatment of waste gases containing
Arsine.   Toyo Oxygen  Co.,  Ltd,
manufactures  a system (TOXOCLEAN
SYSTEM)   that   reduces  the
concentration  of  arsenic  in   waste
gases,    generated  by   the
semiconductor  production  processes,
to meet emission standards (10).   A
schematic sketch  of the process  is
presented in Figure  3.  The exhaust
gases  pass  through  a combustion
chamber,  Venturi   scrubber,   bag
filter, blower, humidifier and the
"TOXOCLEAN".  The  waste gas  enters
the combustion chamber  through  a
nozzle  which  is  protected  from
plugging  and backfire with an inert
gas curtain.   The waste  gas is mixed
with air in the combustion chamber
and the  continuous burnings  occurs
spontaneously.   The fine  particles
formed  by  combustion  are carried
with the gas stream into  a Venturi
scrubber  where most of them, as well
as acidic compounds,  are removed.
At the same  time  the  exhaust gas is
quenched.  The  remaining submicron-
sized  particles are collected by the
bag filter.  The gas is  moved by the
blower through the humidifier  to
control  its  moisture  and
temperature.  The  residual low-level
toxic  compounds   (arsine)  are
absorbed by  TOXOCLEAN.  The  main
ingredient of  TOXOCLEAN  is  FeCl3.
Auxiliary agents are metal chlorides
and  metal   oxides.    Principal
processes  explaining  use of
TOXOCLEAN can  be  written by  the
following reactions:
Absorption
          3 „! 3I¥
H3As03 + 6FeCl2 +6 HC1

Reactivation
6FeClo
         6HC1
         3H20
    The  absorbing  capacity  of
TOXOCLEAN  varies  slightly  as  a
function of flow rate, charging pressure
and the amount of available water.   On
average 1 kg  of TOXOCLEAN absorbs about
50 liters of  AsHg.  The effluent  stream
from the process contains less  than 0.05
ppm of AsHg.

DISPOSAL

    As shown in Figure 1,  most  of  the
arsenic  containing  sludges  are land
disposed.  Since most of these  wastes
contain  insoluble  arsenic compounds,
they are  often disposed in municipal
landfills  (not  hazardous  waste disposal
sites).   There  exist  several  processes
that can be used to  stabilize sludges
containing  arsenic  so that  no leaching
will occur.

    Sludge can  be  treated with a  5%
aqueous solution of thiourea,  sand,  and
Portland cement  at pH  a  of  12.5.
Leaching tests show  that the  leaching
from  the  concrete was  far below  the
regulation  levels  (11).

    Also,  a lime neutralized  sulfuric
acid waste is mixed with lime to  pH  12-
13,  and  the  heated above  720°   to
stabilize  the heavy metals  and arsenic.
Arsenic leaching was nil (12).

    Currently, arsenic disposal  in Japan
does not  cause any  environmental  or
health  problems.

ACKNOWLEDGMENTS

    The preparation of this survey  was
partially  supported by the  Institute  of
Industrial  Science (IIS),  University  of
Tokyo.   Mention of trade  names does  not
constitute endorsment or recommendation
for application.  Thanks  to Dr.  Noboru
Masuko  from  the IIS for  information
useful  in preparing  this paper.

REFERENCES

1.  Sax, N.  Irving,  1979,  "Dangerous
    Properties of Industrial Materials",
    5th Edition,  Van Nostrand  Reinhold
    (1979).
                                     166

-------
2.  Chemical Engineering, 1984, 91,
    No.  16, p.15.

3.   Furukawa Kogyo  Co.,  Ltd., Tokyo
    100,  Japan,  1985,  Personal
    Communications.

4.   Yoshida, K., 1982,  Geothermal
    Journal (Japan),  19, No.  3, pp.
    1-15.

5.   NEC Corporation,  1984,  Japan
    Kokai  Tokkyo Koho JP (Japanese
    Pareut)  95,  991.

6.   Nippon Mining  Co.,  Ltd., 1983,
    Japan  Kokai  Tokkyo Koho  JP  153,
    586.

7.   Unitika, Ltd.,  1983,  Japan Kokai
    Tokkyo  Koho  JP 68, 140.

8.   Mitsubishi  Rayon  Co.,  Ltd.,
    1982,Japan  Kokai Tokkyo Koho JP
    150,  481.

9.   Agency of  Industrial  Sciences
    and Technology,   1980,  Japan
    Kokai Tokkyo Koho, 132,  633.

10. Toyo Sanso K.K.,  Tokkyo 142,
    Japan,    1985,    Personal
    Communications.

11. Yagi   Tetsuro   and   Shiro
    Matsunaga,  1977, PPM  Journal, 8,
    pp.  8-21.

12. Mitsui  Mining and Smelting  Co.,
    Ltd., 1980,  Japan  Kokai Tokkyo
    Koho, JP 8,  729.
             Disclaimer

The work described in this paper was
not funded by the U.S. Environmental
Protection Agency.  The contents do
not necessarily reflect the views of
the Agency and no official endorse-
ment should be inferred.
                                    167

-------
      Figure 1.    Arsenic  flow in  Japan
   From Copper
   Refineries
                                                      Geothermal Power
                                                          Generation
Furukawa Co.
   Metal Co.
 Onohama Co.
                    200t/y
Export to
S.E, Asia
Australia
Araeri ca
                                  Pesticides
                                  and Wood
                                  Preservatives
                                      168

-------
                                Figure 2.   Wastewater treatment  in  a  geothermal  power plant
cy>
                                Steam to Turbines

                                       -3*
                                                                                               ¥°4
                          Environment  „*-
                          Treated Water
                                                                                               Flocculator
                                            Neutralization
                                                 Tank
                                                     Land Disposal

-------
 Figure 3.
TOXOCLEAN SYSTEM
CLEANING SYSTEM OF WASTE GAS
                                                           Clean Exhaust
                                         1 Combustion Chamber
                                         2 Venturi Scrubber
                                         3 Bagfllter
                                         4 Blowar
5 Humidifier
6 Cooler '
7 Ibxodeon
                              170

-------
                     A DECISION MODEL RESUMING PROM THE
                      CLASSIFICATION OF HAZARDOUS WASTE

                      Edward S.Kempa and Ryszard Szpadt
                     The Technical University of Wroclaw
                            50-370 Wroclaw,Poland
                                   ABSTRACT

     In the global waste flow of each industrialized country, we can measure a
specific amount of waste which are hazardous or even toxic. Hazardous waste can
be considered from different points of view. The first one leading to a well or-
ganized waste management should be a proper systematics and classification of
such kind of waste. Before formulating their own new classification of hazardous
waste in Poland, the authors analysed 19 known classifications from different
countries which included 22 various classification criteria. Toxicity irr. relat-
ion to humans, animals, and plants, was mentioned there 18 times, flammability,
13 times, explosiveness, 8 times, reactivity and water-solubility, 7 times each,
etc.
     In Poland, in the management of hazardous waste, various classifications
are used. Recently, the authors have worked out a modern and new one combining
many elements which have proved useful in other classification systems.
     The system in question has been divided into a five-rank classification
(highly active and toxic substances - class I, hazardous substances, harmful
 substances, partly noxious substances, and harmless but troublesome substances
- class V), and the adopted indicators are as follows: toxicity, flammability
and explosiveness, consistence, water-solubility, composition of water extract,
volatility, reactivity, and corrosivity. For each class threshold values of par-
ticular indicators related to the Polish Poison Act, the Polish "later Pollution
Control Act, and to the Polish Clean Air Act have been established. In accord-
ance to the new classification and resulting implications, the authors elaborat-
ed a Decision Model based on local and regional solutions.


INTRODUCTION AND PURPOSE                  material might be utilized or disposed
                                          of.
     Every waste material may be evalu-
ated in terras of many different crite-    Of prime importance is that the follow.
ria. These should be formulated clearly   inS groups of criteria be involved,
and unequivocally so as to enable a re-   when characterizing the properties of
liable characterization not only of the   the waste material:
waste as a whole, but also of its indi-   ^  those of the reoovery of valuxab-
vidual properties. Having such data at        le resouroes included in the was-
hand, one is able to take a relevant          ^g.
decision as to whether a given waste
                                     171

-------
 2. "those of the technological potent-
    ial, viz. appropriate methods of
    processing or disposal, and
 3» those of the noxiousness to man and
    environment, viz. relevant approach
    to the problem of processing or
    disposal, and adequate environment-
    al safeguards.

      Since noxiousness estimates are
 of prime significance to decision-mak-
 ing in the management of solid wastes
 (storage, transport, processing, reuse
 and disposal), they will be the domi-
 nant topic to be considered in this
 paper.
      The classification of waste mate-
 rials in terms of their noxiousness
 which is now being in force in Poland
 has a provisional character (4).-
 Purthermore, .it proved to be inadequa-
 te to meet the demands made on such
 classifications. Hence, there is an
 urgent need to develop a novel classi-
 fication and set a relevant list of ha-
 zardous wastes, providing their detail-
 ed characteristics evaluated from three
 aspects — that of their noxiousness,
 that of the technological potential and
 that of the recovery of valuable re-
 sources. To this purpose, the authors
 will make use of literature data,  as
 well as of their own results and ex-
 perience,

 APPROACH
      To choose suitable criteria - as
 well as to select those applied most
 frequently for the purpose of interest
 - analyses were carried out on home-de-
 veloped and foreign classifications of
 solid wastes in general and hazardous
•wastes in particular (1,2). Thus,  for
 the twenty—two criteria (which have
 been made use of in nineteen classifi-
 cations) the frequency of occurence is
 as follows: toxicity to humans, animals
 and plants, 18 times; flammability, 13
 times; explosiveness, 3 timesj reactiv-
ity, 7 times; water-solubility, 7 ti-
mes; volatility, 6 times; aggressive
action and irritating action, 6 times;
consistence, 4 times, and corrosivity,
4 times.
      The account given above may be
supplemented by a number of new data
obtained by the authors of this paper
from their study on the composition
and properties of,  as well as from the
noxiousness estimates for, solid waste
generated by various industrial bran-
ches.

     Finally, eight indicators (crite-
ria) have been adopted for classifying
the noxiousness of wastes. These rank
as follows:

 A. TOXICITY,
 B. FLAMKABILITY, EXPLOSIVSMESS,
 C. CONSISTENCE,
 D. V/ATER-SOLUBILITY,
 E. COMPOSITION OP WATER EXTRACT,
 P. VOLATILITY,
 5. REACTIVITY,  and
 H. CORROSIVITY.
      On estimating any of the eight
indicators, we make use of a five-rank
classification involving the following
classes:
         I
        II
Class
Class
Class III
Glass  IV
Class   V
toxic waste,
hazardous was t e,
harmful waste,
partly noxious waste,
harmless waste.
      Each class have been assigned  re-
spective threshold values  for every
component included. These  are explicit
numerical values complying with Polish
rules and regulations which are in for-
ce now,  viz.  the maximum permissible
concentration ( MFC ) values determined
for substances creating health hazards
in workrooms, the MFC values for air-
borne substances and pollutants of na-
tural waters, standards for classify-
ing fire and explosion hazards in buil-
dings, corrosive action to building
structures,  etc.
                                      172

-------
     Thus, taking  into  account  the  es-
timates  of individual criteria  (of
which the following  three  -  toxicity
(A), fiamraability, explosiveness (B)
and reactivity ( G) - are regarded to
"be of prime significance), each waste
material can be  assigned to  one of  the
five classes listed  above.

PROBLEMS ENCOUNTERED
     The classification presented in
this paper must  be verified  by  a conti-
nuous investigation  of  new or insuffi-
ciently  recognized wastes. Our  current
knowledge of waste materials, their
processing, reuse  and disposal  is still
far from being satisfactory. This sim-
ple truth holds  for  many industrial
countries. Continuous advances  in indu-
.strial technologies  make the formulat-
ion of adequate  criteria (i.e.  those
for estimating whether  or  not the given
waste is fit for processing, recycling
or disposal) lag far behind. The  result
is that  the decision—makers  seem  to have
difficulty in making appropriate  use of
the available estimation criteria for
technological reasons only. And that is
why there appeared an urgent need to
formulate such criteria for  a number of
processes (biological stabilization,
both aerobic and anaerobic, thermal de-
composition, solidification) even at
the present state-of-the-art. It  often
happens  that no  numerical values  are de-
termined. Nevertheless, this situation
made it  possible to  set the  course  for
a further study.

RESULTS
     The results obtained from  our  study
enabled  a decision model to be  formulat-
ed for the needs of  solid waste manage-
ment (Pig.l). The determination of  such
indicators of the wastes as the physico-
chemical composition, the  class of  nox-
iousness to the  environment, recycling
potential or technological potential,
makes the choice of  managerial  decisions
more efficient and relevant.Decisions
of prime importance should involve
the choice of an appropriate method,
an appropriate site and an appropriate
technological solution when the waste
material is fit for recycling and re-
use (out of hand or in future). Y/hen.
the waste material is unfit for being
recycled or reused, we have to take a
decision as to how to solve the prob-
lem of storage (type of containers),
transport (means of transportation,
reloading), primary processing (pro-
cesses and equipment), processing and
disposal. The decision-maker should
take into account the regulations for
each class of noxiousness included in
the classification. Consideration
should also be given to technological
criteria.

     Further decisions should refer to
the scale (local or regional) on which
the given waste management problem is
to be solved. For this purpose,  the
following parameters are considered:
the quantity of the wastes produced,
the technological potential,  the de-
gree of disposal desired,  and the cost
of the system involved. A further step
in decision-making consists of select-
ing an appropriate site and an appro-
priate capacity for the plants where
the wastes will be subject to pre-
treatnent,  processing and final dispo-
sal. This step must involve environ-
mental, spatial and economic consider-
ations ( 3).
     Successive steps of decision-mak-
ing in a joint management of solid
wastes are included in the decision
model ( Pig.l). The model also gives
successive stages for the identificat-
ion and classification of the waste.
Furthermore,  it enables an appropriate
choice of methods and procedures so as
to meet the requirements of environ-
mental safety.
     The model proposed has the merit
of being applicable to every kind of
                                      173

-------
                                        WASTE  MATERIAL
          Determine families of branches, branches and technologies  generating the waste rr.ate-
          riel of interesti  use symbols  recommended  by  SIC	
          Perform analyses of physieochemical composition, technological  properties and
          degree  of  noxiousness	
         Classify the waste  material  by considering  its  noxious impact
Is the physieochemical
homoqeneaus or not
No
«
and morphological composition of the waste material


Is the waste material fit for
and economic development


H
4
is the- waste material a reclaimed raw materic;
complying with Polish Instructions
»

No 1 Usss

reuse at the present stage of technological


"h*
         Is it  possible  or not to develop a tech-
         nology of processing and  reuse for the
         given  waste  material  ?
Is a  temporary storage  of  the waste  ma -
ierial for future  reuse  feasible or  not ?
                    NoL
Storage  in  compliance with  the  class
of  noxiousness
Is a  direct reus* (without  processing  the
te material 1  feasible  or not ?
                                                                    • No	
                                             No
                                                      Processing
                                                                                      Reuse
                                                                                                  -t
Separation of one or mo-
re than one component
without influencing the
composition or the form
of the waste materfal

Processing proceairs
affecting the caoao:—
sition and the fanr
of the waste ntcr=E —
rial . ,
                                                Remainder t
                              -*  Materials
                                                                                  Reuse
                       WASTE  MATERIAL  UNFIT  FOR  REUSE
CLASSIFICATION
Class 1 | Class II 1
INVOLVING NOXIOUSNESS
Class ill i Class IV | Class V )
STORAGE AT THE SOURCE OF ORIGIN. TRANSPORT. TRANSFER- t
Air- tight tanks |

i 1
' J
Sealed tanks 1 	 3
J_0oer: tanks 4
4 	 e—
PRIMARY PROCESSING
! Deloxication
	 	 t
[jCheraieal treatment, neutralization . chemical precigitation _[
£ Separation of jjhases (distillation, dewaterina.de-emuisifying . filtration j
4 A
y 	 1 	
PROCESSING AMD DISPOSAL
1 Incineration J ',
[ Pyrolysis
1 Solidification
F Biochemical
4- i
i
1
stabilization 1
4 4
REUSE OF THE REMAINDER FROM PROCESSING
1


U, 	 ^ 	 1

r*
4 •»•

-
ULTIMATE DISPOSAL OF THE WASTE MATERIAL OR RSMAINOE3
1 First- class loncfil! J :

[Second-class landfill
ISanitary landfill


|Ihrc-i.ass .crcr".: 1
        Fig.1  MoCel  of  decisions  for  the  needs  of   hazardous wos:e   rncnagement
                                                 174

-------
waste material fit for recycling or
disposal, to every source of generat-
ion (industrial enterprises) and every
region for which rationalized solutions
are being, planned.


ACKNOWLEDGMENTS

     This paper has resulted from the
Research Project 10.2., supported and
co-ordinated by the Institute of Envi-
ronment Engineering Fundamentals of
the Polish Academy of Sciences.


REFERENCES

1. Kempa, E.5., 1983. The Role of Low-
   Waste Technologies in the Management
   of Hazardous Waste in Poland, Indu-
   stry and .Environment, UNEP Publ.
   Paris, Special Issue No.4,pp. 39-45

2. Kempa, E.g., and R. Szpadt, 1984,
   Criteria for estimating the environ-
   mental impart of industrial wastes
   and methods of utilization. Report
   of the Institute of Environment
   Protection Engineering, Technical
   University of Wroclaw (in Polish-;
   unpublished).

3. Kovalick, W.W. et al.[Editors],1977,
   State Decision-Makers Guide for Ha-
   zardous V/aste Management, U.S.EPA
   Publ.No.SW-612, Washington D.C.

4. Preliminary recommendations for the
   classification of waste, 1980, War-
   szawa (in Polish).
APPENDIX

     Classification of hazardous
           wastes in Poland

Indicators in details

TOXICITY

Class I - wastes containing, in quan-
tities exceeding 0.1 per cent of dry
mass, the following substances:
 a/ those  mentioned as  poisons  -  list  A
    in the Polish Poison Act  of Decem-
    ber 28,  1963,
 b/ those  whose MPC in  the  air  of work-
    rooms  does not exceed 0.0001  g/rn-^,
 c/ those  whose MPC (20 or  30 min) in
    the air in protected areas  does not
    exceed 0.01 mg/ra-%
 d/ those  whose MPC in  surface  waters
    of the first purity class does not
    exceed 0.05 g/m^,
 e/ those,  not mentioned above, whose
    LD,-. does not  exceed 50 rag/kg (for
    rats per os) or whose LCj.   does not
    exceed 100 mg/ttg and other  substan-
    ces of toxic properties correspond-
    ing to the above mentioned  substan-
    ces.
 Class  II  -  wastes  containing in  quanti-
 ties  smaller than  0.1 per cent of  dry
 mass  the  substances of  class I and in
 quantities  exceeding 0.1 per cent  of
 dry mass  the following  substances:
 a/ those  mentioned as harmful means —
   list B in the Polish Poison Act men-
   tioned above,
 b/ those  whose MPC in the air of work—
   •rooms  varies from 0.0001 to 0,01
   g/m3,
 c/ those  whose MPC (20  or 30 min) in
   the air  in protected areas varies
   from 0.01 to 0.1 mg/m^,
 d/ those  whose MPC in surface waters
   of  the first class purity varies
   from 0.05 to 1.0 g/m-3,
 e/ those,  not mentioned above,  whose
   LDj.., equals 50-500 mg/kg or LC,-O =
   100-1000 mg/kg and other substances
   of  toxic properties corresponding
   to  the above mentioned substances.
 GlassIII - wastes containing in quan-
 tities exceeding 0.1 per cent of dry
mass the  following substances:
 a/ those whose MPC in the air of work-
   rooms varies from 0.01 to 0.1 g/m3,
b/ those whose MPC (20 or 30 min) in
   the air in protected areas varies
   from 0.1 to 1.0 mg/m-^,
                                     175

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c/ those whose MFC  in surface waters
   of the first  purity class  varies
   from 1.0 to 10.0 g/m^,
d/ those, not mentioned above,  whose
   IiDg. equals 500-5000 mg/kg and
   otner substances of harmful proper-
   ties corresponding to the  above
   mentioned substances.
Class IV - wastes containing  in quanti-
ties smaller than 0.1 per  cent of dry
mass the substances of class  III and in
quantities exceeding 0.1 per  cent of
dry mass the following substances:

a/ those whose MPC  in workrooms exceeds
   0.1 g/m3,

b/ those whose MPC  (20 or  30  min) in
   the air in protected areas exceeds
   1.0 mg/nr,
c/ those whose MPC  in surface waters
   of the first  tmrity class  exceeds
   10 g/m3,
d/ those, not mentioned above,  whose
   LD__ equals 5000-15000  mg/kg and
   otner substances of harmful proper-
   ties corresponding to the  above  men-
   tioned substances.
Class ¥ — wastes containing no  harmful
substances  I|l'cO> 15000 mg/kg .

PLAMMABILIIY AND EXPLOSIVENESS
GlassI - extremely easily flammable
and/or explosive wastes:
a/ wastes evolving  gases of lower ex-
   plosive limit at concentrations  up
   to 10 per cent of volume in a mix-
   ture with air,
b/ wastes containing liquids  of an  ig-
   nition temperature ^ 294 K.  At a gi-
   ven concentration,  the  vapour of
   those liquids are ready to  form  an
   explosive mixture with  air,
c/ wastes containing solid substances
   which are flammable  when exposed to
   water or air humidity,  or  when get-
   ting in touch with  atmospheric air.
Class II - easily flammable and/or
explosive wastes:

a/ wastes evolving gases of lower ex-
   plosive limit at concentrations
   higher than 10 per cent of volume
   in a mixture with air,

b/ wastes containing liquids of an, ig-
   nition temperature between 294 and
   328 K; at a given concentration,the
   vapours of those liquids are ready
   to form an explosive mixture with
   air,

c/ wastes containing fine solids which
   are ready to form flammable_ suspen-
   sions of fibres and dust particles
   produced during processing or trans-
   port | these occur in amounts facili-
   tating generation of an explosive
   mixture when getting in touch with
   atmospheric air.

Class III - flammable and/or explosive
wastes:
a/ wastes containing liquids of an ig-
   nition temperature between 328 and
   373 K; at a given concentration,the
   vapours of those  liquids are ready
   to form an explosive mixture with
   air,
b/ wastes containing easily flammable
   solids which occur in amounts in-
   sufficient to form an explosive
   mixture with air.

Class IV - flammable wastes:

a/ wastes containing liquids of an ig-
   nition temperature > 373 K,

b/ wastes containing either slow-bum-
   ing solids or such that occur in  a
   form resistant to ignition (.e.g.  in
   humid form).

Class V - non-flammable wastes.
CONSISTENCE

Class I - liquid wastes,
Class II — semi-solid wastes (of the
           consistence of pula,  slirae,
           paste, dough,  etc.5 ,
                                     176

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Class III - solid, dusty and loose
            wastes,
Class IV - Solid, coarse-grained was-
           tes of the consistence of
           wet earth,
Glass V - solid wastes, rocky, lumpy,
          solidified material.

WATER-SOLUBILITY
Class	I - very easily soluble wastes;
          in the standard test 90-100
          per cent of the mass are
          dissolved,

Class II - easily soluble wastes, 10-
          90 per cent of the mass,

ClassIII - moderately soluble wastes,
          1-10 per cent of the mass,
ClassIV - slightly soluble wastes,
          0.1-1.0 per cent of the
          mass,
Oljass _V - practically insoluble was-
          tes, less than 0.1 per cent
          of the mass.
                                         VOLATILITY
                                         Cla_ss I - very easily volatilizing
                                         wastes containing substances with a
                                         volatility index  Iv    lower than 5,
                                         which, constitute more than 1 per cent
                                         of the total mass,
                                         Glass II - easily volatilizing wastes
                                         containing;

                                         a/ substances of I < 5, which consti-
                                            tute less than. I per cent of the
                                            total mass,
                                         b/ substances of Iv = 5 to 50, which
                                            constitute over 1 per cent of the
                                           .. total mass.
                                         Class III - moderately volatilizing
                                         wastes containing: •
                                         a/ substances of Iv = 50 to 200, which
                                            constitute over 1 per cent of the
                                            total mass,
                                         Class IV - slightly volatilizing was-
                                         tes containing:

                                         a/ substances of Iv = 50 to 200, which
                                            constitute less than 1 per cent of
                                            the •total mass,
                                         b/ substances of Iv = 200 to 2000,
                                            which constitute over 1 per cent of
                                            the total mass,
®   '                                     Class V - wastes with no volatile com-
ClassII - water extract contains sub-   ponents or wastes containing substances
COMPOSITION OP WATER EXTRACT
Class I - standard water extract con-
tains substances of the first toxicity
class in concentrations exceeding 0.01
stances of the first toxicity class in
concentrations lower than 0.01 g/m3
and substances of the second toxicity
class in concentrations exceeding 0.1

Class III - water extract contains sub-
stances of the third toxicity class in
concentrations exceeding 10 g/ra3,
Class IV — water extract contains sub-
stances of the third toxicity class in
concentrations lower than 10 g/m3 and
substances of the fourth toxicity class
in concentrations exceeding 10 g/nH,

Glass V - water extract does not con-
tain any harmful substances.
                                         of I
                                                 2000.
                                         REACTIVITY
                                         Class I - wastes containing substances
                                         which may react with water, air or soil
                                         to yield:
                                         a/ first-class-toxicity products; deg-
                                            ree of reaction,> 0.1 per cent of
                                            mass of the waste,
                                         b/ second-class-toxicity products; de-
                                            gree of reaction, 90 to 100 per cent
                                            of mass.
                                         Class II - v/astes containing substances
                                         which may react with water, air or soil
                                         to yield:
                                     177

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    The  decree  regarding solid waste
(urban,   industrial,  hazardous  and
toxic),   added  to  the  existing
government  regulations on  air  and
water pollution control, specifies the
provisions to be made  by national,
regional, provincial and  municipal
authorities.

    They are  as follows:

    The national  authority must

    -  establish general  criteria  for
      waste disposal methods;
    -  establish  the means  to  be
      adopted to avoid an  increase in
      refuse  and waste;
    -  coordinate  regional programs.

    The regional authorities must

    -  draw up organizational plans;
    -  authorize disposal  sites;
    -  approve treatment plants.
   Provincial  authorities
   charge of control.
     are  in
   The  duties   of  municipal
   authorities  include  urban  and
   civil waste disposal.
   Operating  criteria,
   guidelines include:
based  on  EEC
   - authorization for landfill ing
     (characteristics  of  area,  types
     and maximum quantities of waste,
     duration and recovery of area);

   - cost of refuse/waste disposal to
     be charged to the producer of
     waste;

   - authorization of collection,
     transportation,  temporary
     storage,  processing and final
     storage of  toxic  and  hazardous
     waste in  controlled areas.  It
     is compulsory for producers and
      transporters  of waste  to
      maintain  a  register,  and  an
      identifying   receipt must
      accompany   waste   during
      transportation.

    Finally,  a  fine of  up to five
    million  Lire   and  one  year's
    imprisonment are  the penalties for
    non-compliance with the law.

    A  definition   of  toxic  and
hazardous waste (for which the  law
provides  special regime and severe
penalties) can be had  from  the three
following  suppositions:

1.  The  waste   contains,  or  is
    contaminated by, one or more of
    the  28  classified  groups  of
    substances listed in the attached
    Decree 915.

2.  Those substances are present in
    such   quantity   and/or
    concentration as  to  constitute a
    danger  to  human  health  or  the
    environment.

3.  The  technical parameters used  to
    define the characteristics of  the
    toxic  and hazardous  waste have
    been  determined  by  an  apposite
    interministerial committee.

    As Sanitary Legislation Act 833/78
provides for the creation of health
conditons  uniform   throughout  the
national  territory,  the  concept  of
toxic waste obviously must also  be
uniform  and  valid   throughout  the
country.

    The provisions of the  law  require
that the interministerial committee
follow  strict  criteria  of rigid
classification  in  determining  the
presence of the 28  classes  of toxic
and hazardous compounds listed.  That
classification  presents  serious
difficulty  in  analysis  and
                                 180

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consequently objective difficulty for
waste producers  and  control agencies.
To overcome  these difficulties,  clear
scientific criteria  should  be  adopted
for determining limits of harmfulness.
Similar criteria have already been
applied  on an  international  level, as
well  as technical   requisites  and
operative   procedures for disposal
sites for toxic  and  hazardous  waste,
adequate for  the protection of the
environment  and   public   health
requirements.   Regulations  for the
moment take into consideration only
compost   production,  recovery  of
landfill biogas and incineration,
however leaving   space   for  the
utilization  of other techniques.
Following   the example  of  other
countries, a  classification  system for
toxic and hazardous waste  is also
foreseen based on the source of the
waste.  Also provided by the law is
the  producer's  right to  prove  the
absence  of toxicity  in waste material
following   previously  prescribed
procedure.
CRITERIA OF ACCEPTABILITY FOR
WASTE DISPOSAL TECHNIQUES

    The law intends to "provide the
formulation  of basic  criteria and
technical  guidelines for the disposal
of  waste  in  general,  as  well as
provide   general  criteria  for
authorizing the disposal  of toxic and
hazardous  waste".

    It  also  states  that  "actions
permitting the quantative reduction of
waste introduced into the environment
and  the  lowering  of  the  level of
harmfulness of the same as regards man
and  the environment are concurrently
Imperative for the implementation of
the general terms of Decree No. 915".
Such  actions  can be  set  out  as
follows:

a)  intervention  in  the production
    cycle and phases  of distribution
    and consumption, with the scope of
    limiting the formation of waste in
    the  environment  and during  the
    phases themselves;

b)  intervention during the various
    phases of waste disposal, with the
    scope  of  recovering  waste,
    materials and sources of energy;
c)  intervention
    efficiency
    materials
    expansion
    themselves;

d)  intervention
    of recovered
    production
    construction
for the improving  of
 in  the  recovered
 markets  and  the
 of  the  markets
 to  increase  the  use
 materials during  the
 cycles and  in the
of works.
                                      The  resolution cited
                                      general  criteria for
                                      f o.l 1 ows:
                       also defines
                       disposal, as
    "The  choice of system,  technology
and technical means to be used must be
based on a  comparative evaluation  of
the,  different solutions  which  are
technically  and economically feasible,
keeping  in  mind,above  all,  the
imperative  of avoiding  a negative
impact on man or his environment.

    Keeping in mind  such criteria,
preference is  made for  systems which
ensure a  considerably higher  level  of
recovery  of  materials and  energy  for
which  there  could  exist concrete
possibilities  for  commercialization
and recycling."
                                  181

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    The law also specifies the phases
which allow a disposal  of waste within
limits imposed  by hygienic/health
requirements and the protection of the
environment.   They are:   collection,
treatment, definitive disposal  and
interventions on the release of solid,
liquid or gaseous substances resulting
from  the  preceding  phases and  the
secondary  operations  of manipulation
and transfer.

    The reduction  of operative  costs
is  obviously a  matter  of  optimum
localizing of the treatment plants.
This  could be  done by intermediate
stations.   Such localizaton would also
take into consideration the positon of
the landfill  sites  where the residues
are to be disposed of definitively.

TREATMENT CENTERS

    Presently, in Italy the "treatment
centers",  in  consideration of  both
transport costs  which are relatively
contained  due  to   the   high
concentration  of sludge and  residual
materials,   and  the  particular
difficulties   met  with  in  home
treatment,  are  consolidating   and
forming  coalitions  of  public  and
private  firms.   Internally,   the
operations carried  out  are  those
typical to chemical  engineering, such
as  the   various  operations  of
transformation  (such as chromates,
cyanides,  phenols)  and those of
separation  (such  as  filtration,
decantation,    extraction,
centrifugation,  distillation), and  so
on.

    The  processes  utilized   are
chemical,  physical  and  biological,  and
are   conveniently   integrated.
Elimination of organic residual
substances when possible is done by
means of combustion and landfill ing
preceded  when  necessary  by
stabilization processes.
    The  major  problems as regards the
activity of such centers are mainly:

a)  analytical  control in real  time of
    the  different lots  of material
    introduced;

b)  the   computerization  of  all
    administrative  and  technical
    operations;

c)  the  search  for  new  means  of
    treating the different residues.

DEVELOPMENTS

    New  from the technological  point
of  view   are  the  systems  for
stabilizing the landfills by means of
controlled  leachate  collection  in
aerobic  conditions.  The  advantage in
this type of center is the possibility
of a more efficient  public control.
The advantages for the producers of
residues are,  in addition to a more
simple operation, of  an  economic and
financial  order.   A  major  problem
presently being confronted concerns
the localization of  the dump sites.
Procedures for environmental  impact
have  not  yet  been introduced into
Italian  legislation,   and there  exist
no public participation programs, such
as the siting boards encouraged in the
U.S. with authority to approve  or deny
permits  for waste facilities.

    Following  are the findings of a
workshop recently conducted at  Genoa
University:

    In this sector, in Western Europe,
there  is no  clear-cut "polluter pays"
principle.    It  would  be  advisible to
define  a  more equitable  system  of
financing.   Regarding  the transfer of
waste  over national  borders, the most
suitable control  mechanisms  are:
                                  182

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      procedures for "formal contracts
      for work";
      procedures  for  informing
      authorities in time to  permit
      prior agreement;
      clearly  defined procedures  for
      exporter-importer approval;
      simple,  effective documentation
      systems;
      a system  for central  records
      control.
    Policies  for
management  could
providing:
waste  control
be  improved  by
    - a licensing system for the site;
    - a licensing system for waste
      transporters;
    - a system  for  monitoring  and
      surveilling   the  licensed
      operations;
    - a system  for identifiable legal
      constraints on  site management,
      transporter and  discharge  of
      waste;
    - an implementation of effective
      national  and  international
      planning  operational Codes  of
      Practice.

    Further development would also be
advisable  for  methods  of  disposal.
The  principal  disposal  route  is
landfill.   Cost-effectiveness  must  be
determined by each  individual case.
Industry operates on  its own survival
profit policy.   It might be  wise  to
allow  it  to  determine  its  own
processes  for  recycling  and recovery.
However, that should  always be within
the limits  imposed by the safeguarding
of the environment.

    Research presently being conducted
falls into three categories:

    1.  Data and Information
    2.  Definition of  Waste Difficulty
       Levels
    3.  New Processes
       A  generic  listing of difficult
waste materials should be available,
instead of one  which  lists individual
compound  properties.   Research  on
disposal   should  also  relate  to
disposal groups.

CONCLUSION

       It  might be  added, in closing,
that in the interests  of international
scientific  cooperation,  and the
obvious benefits which would  result
for all concerned, it is  to be hoped
that in the near future new life  be
given  to  the  on-going agreement
between Italy and  the  United States.
                                 Disclaimer

                   The work described in this paper was
                   not funded by  the U.S. Environmental
                   Protection Agency.  The contents do
                   not necessarily reflect the views of
                   the Agency and no official  endorse-
                   ment should be Inferred.
                                  183

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                      MANAGEMENT OF HAZARDOUS WASTES
                          IN EGYPT, AN OVERVIEW

                       Prof. Dr. Saraia G.  Saad and
                          Dr.  Hosny K. Khordagui
                     High Institute of Public Health
                            Alexandria, Egypt
    Statutory definitions of hazardous
waste  used  by various countries
reflect not only  the  nature of the
environmental  problems,  but  also the
social,   political  and  economic
conditions of the countries concerned.
When attempting to define hazardous
wastes they lie in one of the basic
categories:

a)  Short  term acute hazards,  such as
    acute toxicity  by ingestion,
    inhalation or  skin absorption,
    corrosivity or other skin or eye
    contact  hazards or  the  risk of
    fire or explosion, or

b)  Long  term environmental  hazards,
    including  chronic toxicity upon
    repeated exposure, Careinogenicity
    (which may  result  from  acute
    exposure,  but  with  a  long  latent
    period),   resistance   to
    detoxification process  such as
    biodegradation,  possibility of
    underground or  surface  waters
    contamination or  aesthetically
    objectionable properties  such as
    offensive odors.

    Wastes with  these  properties may
be products, side products, process
residues, spent reaction  media,
contaminated plant or  equipment from
manufacturing   operations,  and
discarded  manufactured  products.
    The  management  cycle  for  any
particular  hazardous  waste  comprises
its generation, transport,  storage,
treatment  and  final  disposal.  One
approach  to the  problem of adequately
defining  what constitutes a hazardous
waste  is to draw up  a list of known
wastes that present  no significant
short-term handling or  long-term
environmental hazards, and  to  define
hazardous wastes by exclusion i.e. as
any wastes  not  listed.   This list is
based  on  the criteria that  the waste
should  not contain  any  hazardous
quantity  or concentration of  any
poisonous, noxious or polluting
substances. Clearly  many hazardous
characteristics,  such  as corrosivity,
flammability, and high acute toxicity
by  ingestion,   inhalation  or skin
absorption,  will  cause  potential
problems  at all  these  stages.

    By contrast,  many  wastes that
offer  no  significant  short-term
handling  hazard may cause  severe
disposal   problems  due  to  their
physical or chemical properties  (1).

    In  developing   nations,   the
management of  hazardous wastes can
face  its  biggest enemy,   which  is
essentially  the ignorance of  the
extent of the problem  and consequently
the unwillingness to  take  the  proper
measure  to execute   the  management
policies.
                                    184

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Proposed PlanforHazardous Waste
Management  In Egypt:

    Egypt   now   is   in   the
industrialization  era.   Lots of  raw
materials  are  imported  to  suit  the
requirements  of the  vast array  of
industries  localized in the different
metropolitan areas, such as Alexandria
Cairo, as well  as those scattered all
over the Nile valley.

    Lack of proper industrial  planning
has led  to heavy  concentration  of
industry, in Alexandria's  metropolitan
area,  with a significant high level  of
pollution   as   all effluents  are
discharged  without  any  treatment.
Organic  and   inorganic chemical
industries have  contributed measurable
amounts  of heavy  metals and toxic
substances cyclic  and  alicyclic
compounds.   An   example  of  the
industrial  loads  discharged by  the
Alexandria Metropolitan area are shown
in Tables 1,2 by Hamza (1983).

   The   national  approach  to
establishment,  organization  and
implementation  of a system  for  the
management  of  hazardous waste should
reflect the constitution, legal system
and political  objectives  of  the
country.  The major part  of  industry
in Egypt is owned by the  government
and, at the same time, the government
is responsible for avoiding the random
provision and distribution of disposal
facilities and for  ensuring  the
environmentally  acceptable treatment
and disposal of hazardous  waste.

    This  situation posed  a double
financial and executive burden on  the
government.  This basic idea was  taken
into consideration when planning  for a
management policy.
Survey Hazardous Materials:

    An essential  requirement  for the
realistic planning of hazardous waste
management is an adequate knowledge of
the  quantities and  types  of  waste
produced.  The first step  should be
collection and evaluation of existing
data  on  the  distribution of  wastes
generated and on  the total  amount of
waste requiring treatment or disposal.

    Parallel  with  this exercise,  a
review of the existing waste treatment
and disposal  facilities  is essential.

    The data  collected during  this
stage, based on government agencies
information,  was not sufficient  to
give  a  full  picture  about  the
realistic  situation.   Deviations  are
due to the following  factors:

1)  Lack of proper housekeeping in the
    Egyptian  factories   leading  to  a
    higher percentage of raw  material
    losses  in  the   waste  with   a
    consequent raise in the organic
    and  inorganic loads   in the  final
    effluent  of the  plant.   This  is
    obvious   in   practically  all
    canneries  and   food processing
    plants.

2)  The old  technology  used in the
    already established  plants  allows
    for  mishandling  of  chemicals  and
    raw materials as  well as products.
    A  vivid  example  is  the  discharge
    of mercury  to   the  sea  from  a
    caustic  soda plant using the
    electrolytic   process   in
    Alexandria,   where   ten  tons of
    mercury find their  way annually
    into  the  sea.
                                    185

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3)  The dirty technology  exported  by
    developed  countries to  avoid  the
    high  cost  of  labor  and  the
    skyrocketing  expenses  of toxic
    waste handling and  treatment  due
    to  the  presence   of  strict
    applicable laws.  Processing  of
    dyes and  intermediates by Ismadye
    company is  another dangerous
    example.

4)  Lack of proper knowledge about the
    extent  of hazards  created  by  the
    different components,  from  the
    petroleum  fuel used in boilers  to
    the flammable  solvents and to the
    carcinogenic  chlorinated
    hydrocarbons produced  by pesticide
    producing companies.

5)  Socloeconomic  factors leading  to
    the  carelessness  of   human
    operators  and  their unwillingness
    to adopt  better production  and
    operation  systems.

    The above listed factors make  the
standard  procedures  of   sending
questionnaries and depending  on the
data supported by the  governmental
agencies  a false base.

    The more proper methodology for
developing  countries  would  be   to
convince the industrial  managment
authority,  1n the different  plants,
that the government will help them
overcome their problems and  that,  the
more   positive  and  accurate  the
response  of  the  industry, the better
their  chances to get first priority in
the allocation of funds for  solving
their  hazardous waste problems.

    Training  programs carried  out  by
academic organizations will  help  in
creating awareness in the  different
industries about the extent  of hazard
each specific industry is creating  for
Its surrounding environment, of which
the industry personnel  are a part.
    Upgrading the  technical-level
awareness  as to the  size  of the
problem  will  make the reporting of
realistic information about  the  waste
a more accurate process as  operators
of all  industries are the best people
to give a true picture of the pitfalls
of  the   technology  used  in their
plants.

    Surveying  has to be carried  under
the supervision and  with  the  help of
environmental  organization staff, not
with the  attitude of picking on the
mistakes, but  with the idea of helping
the industry  to  solve  its  problems
with hazardous wastes.

    Surveying  is  planned  to  be  taken
in the following steps:

1)  Contacts  with  the  ministry of
    industry   and   its  affiliated
    industrial organization  for the
    allocation of industrial plants
    and categorization of industries.

2)  A questionnaire has been prepared
    to  be  sent to all  plants  as a
    request from the  ministry with the
    concept of sizing the problem and
    the  needed  budget  for  its
    solution.

3)  Academic  organizations  in
    different  metropolitan areas will
    be responsible for verification of
    the collected  data and, in case of
    a  feeling   of   unrealistic
    information (which can be the case
    in most instances),  the  surveying
    group has  to visit  the plant and
    work  to correct the  data, together
    with   management,  raise their
    awareness  of the magnitude of the
    problem, and discuss the  best way
    to approach the government to seek
    financial  support for the needed
    on-site treatment or methods of
    final disposal for their  hazardous
    wastes.
                                   186

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    A  data  bank  for the  different
souces of industrial polllutants  can
be started and fed with all  this basic
information.   This will  help  in
evaluation of new technology as far as
its hazards  and  the  best site for its
allocation,  as well as the best way to
handle  its  toxic  or  hazardous
effluents as generated in the selected
site.

Haste Pisposal PIans_;

    Comprehensive waste disposal plans
can be prepared based on  the collected
information.    Plans  have  to  be
prepared  to  suit the requirements  of
each  governorate  where industrial
centers  are located.  The  following
subject  areas  will be taken  into
consideration to be covered:

1) The  kinds  and  quantities  of
   hazardous  wastes expected to be
   treated  and disposed  of in the
   area,  including  wastes  generated
   by the governmental authorities
   responsible for handling  the
   combined domestic and  industrial
   effluents in certain  metropolitan
   areas, as in Cairo and Alexandria.

2) The number,  type and location of
   receiving centers and pretreatment
   facilities.

3) Management  of  the waste disposal
   facilities, as owned by  the
   government,   and  the   best
   administrative  measures  to be
   pursued  to ensure success in their
   operation.

4) Proposed  methods  of  disposal
   and/or recycling.   The economy of
   developing countries  has  to be
   taken into consideration.   This
   area  is  also  inviting for foreign
   technology to find a good  market
   for  treatment  and/or  recycling
   units.
5)  Identification  and location  of
    special facilities  suitable for
    individual particularly-hazardous
    wastes.   The  governorate  must
    locate those  facilities as far as
    possible  from   residential  areas
    and also prevent unplanned housing
    projects  from coming so close  to
    those  plants  that,  due  to
    ignorance, there could  be exposure
    hazards to the  inhabitants.

Characteristics of SitesSuitable for
Hazardous Waste pi sposal:

    Due to the limited  funding that
can be  allocated for hazardous  waste
disposal in Egypt,  it is advisable to
join   both  domestic  refuse  and
industrial hazardous waste  disposal in
one facility  owned and operated  by
governmental  agency.

    Large  public-sector firms,   as  in
the case  of textile  plants,   steel
mills,  paper-processing  firms and
especially organic  and  inorganic
chemical  processing industries, can
handle their own disposal  sites and
facilities.  Big  industrial complexes
comprising varying  industries  as  in
Helwan,  Shoubra,  Kafr El  Dawar,  El
Seiuf, Moharrem  Bey and El Max, can
operate an incineration facility  to
get rid  of their  combustible hazardous
wastes.

    Problems may arise even at  the
stage  of selecting the location,  with
objections raised by the  industries as
being too far or not convenient  for
some of them.  This can  be  overcome by
the   governmental   authorities
responsible for operating the  site  by
charging variable  rates  based on  the
extent  of  toxicity,   corrosivity,
flammability, or carcinoglncity,  as
well as distance and cost  to  be paid
by the  producing  firm.   On the  other
hand, levying taxes on  the chemical
                                    187

-------
products  and  on  producers will help
raise  funds for  operation  and
maintenance of hazardous wastes
handling  facilities.   This will also
prompt producers  to limit their  wastes
through better housekeeping and  to try
to recycle and produce beneficial side
products from their wastes.

    This collected fund  will help In
hazard  waste facility  purchase and
site  preparation,  as  well as  its
operation and maintenance.

    General  subsidies  given  to
producers and manufacturers  should be
avoided because  they may remove the
economic  incentive to recycle  wastes
or to recover value from them.

    Governmental funds  can  only be
resorted  to when there is a need to
Improve the technology to adapt to a
new  hazardous waste  generated by a
newly introduced  process.

    Landfill  is  the  best technology
that can  be afforded by developing
countries  such as Egypt.   The  physical
factors of  greatest  concern are the
soil  characteristics  and  groundwater
conditions.   For  a  collection  and
processing  site,  the  most improtant
considerations   are  the  industrial
burden  already existing in the area.

feoreholes  of the  soil  at  the  selected
sites  will  show  the  level   of
groundwater and  its salt  content.
This  will dictate the quality of the
hazardous wastes to be  disposed  at
that site by surface spreading  or
controlled dumping.

Legal and  Administrative
Requirement

   A  comprehensive  system  for  the
disposal  of  hazardous  waste  will  not
develop  unless its basic  requirements
are prescribed and dictated by law.
     Assessment of the existing laws
 and  regulations in  Egypt  showed
 clearly that the concept of health-
 hazard  effects  of toxic  or  hazardous
 constituents is not really understood.
 Parameters  like  those  describing  the
 biological and chemical amenability to
 degradation are listed.

     Hazardous  waste  legislation will
 have to impose duties  on  the  general
 public,  and the present law  should be
 modified to impose those duties.

     The technical  aspects of hazardous
 waste management should, therefore, be
 governed   by   statutory   or
 administrative   regulations,    as
 appropriate.

     The most  important  task  for
 hazardous waste management legislation
 in  Egypt  is  the designation  of
 responsibility for disposal.    Public
 authorities can handle it themselves.
 This  system  has  a basic  disadvantage
 of being excessively bureaucratic  and
•inflexible and may not be  adequately
 sensitive   to   cost   benefit
 relationships or to local public  or
 industrial  needs.

     The  major  advantage would  be  the
 assurance of having a running  facility
 that  can accommodate different  wastes
 to suit the environmental requirement.

     The  legal  responsibility  for  the
 proper disposal of waste should  remain
 with the waste generator who should be
 responsible for the folowing:

     The choice of  proper transport  and
     disposal  methods  for the waste  in
     question.

     Avoiding,  minimizing,  and
     recycling  wastes  as  far  as   is
     technically   possible  and
     economically reasonable.
                                     188

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Table 1  Estimated waste loads of pollution-contributing industries in Alexandria Metropolitan Area
Industry
Pulp & Paper
Paper Conversion
Textiles
Dyes
Fertilizers
Steel
, Oil & Soap
Tyres
Refineries
— • Chemical (Inorganic)
00
to Tanneries
t Power
Match
Electronics
Refractories
Plastics
Bottling
Canning
Dairy
Yeast & Starch
Brewery
Poultry
Pharmaceuticals
No of
Plants
2
3
13
1
1
1
8
1
2
1
6
2
2
1
1
1
2
2
1
3
1
1
1
Discharge'
S
L.S.D
L.S.D
S
S
Se
Se.C
Se
S.L
S
S
c
I
D
D
D
Se
D
D
SE.L
' Se
D
Se
F low
ML/d
93
5
37
4
30
13
32.5
4.3
230
35
1.6
324
1.1
0.5
0.5
2.5
1.9
4
0.8
3.2
1.2
0.5
0.9
BOD
83462
3679
19895
983
252
520
30935
504
12615
10850
,2688
7662
496
138
147
788
484
3000
1240
2440
386
429
576
(Kg/day!
COD O&G
103356
7379
37877
580
1392
1430
61943
1260
41875
22035
4109
12022
862
269
297
725
693
4264
3660
3360
184
583
936
1817
1996
31 14
48
276
170
9800
286
10740
3215
405
11248
98
59
171
395
89
177
950
106
41
51
39
SR
56069
7543
29949
366
558
585
44685
940
24370
39050
13600
15606
1085
320
806
713
256
1137
2982
1950
160
681
108
VR
80635
7454
41312
447
1032
890
51202
1092
44770
35600
11424
12987
1452
356
716
905
432
2258
6055
2130
192
693
475
P
302
43
116
3.1

8.6
6.7
5.4
36.6
74.1
43.1
135
8.2


11.3
6.0
5.4
2.5
8.6
1.6
2.5
4.5
N
210
12 5
123
2.5

4.3
56
4.3
37.4
195
24.3
128
28.6
2.1

19.4
9.3
3.1
3.0
5,1
0.6
3.1
0.7
               Total
57
                  828
184235    311591    45330   243519   304509
                                                                                                     886
1094
 (1) L - Lake  S = Sea  Se = Sewer  C = Canal  D = Drain

-------
                Table 2  Average analysis of trace metals in selected industrial effluents
to
o
Source
Copper Works
Canning
Dairy
Tyres
Textiles
Paper Conver.
Electronics
Oil & Soap
Tanneries
Inorganics
Foundry
Zn
594
1800
1144
6285
101
11.3*
6250
5550
2133
381
8400
Cu
450
30
185
400
107
220
70
95
603
355
290
Ni
388
5
234
ND
198
20
ND
60
545
475
30
p.9/1
Cr
ND
20
210
150
ND
360
50
30^
127*'
ND
460
Cd
ND
0.5
0.5
0.5
2
3
8
0.5
715
29
3
Fe
1392
2200
3275
2550
320
4050
1525
• 3625
14*
1776
21800
Mn
144
340
355
205
119
480
373
445
979
216
630
Pb
209
30
255
45
102
410
255
285
1238
527
260
                 "Concentrations in mg/l

                  ND= Not Detected

-------
    Correct ceclaration  and  proper
    labeling according to the newly
    set  legal requirements.
Control  of HazardousWaste
Management

    One   of  the  basic   legal
requirements for  the implementation of
a reliable system  of  hazardous waste
management  is the establishment of
comprehensive control mechanisms.
    There  are three
measures to control
management.
basic groups of
hazardous waste
    The  first  step is the control of
waste generating process.  This should
be  controlled by the  Ministry  of
Health legal  requirements  aimed at
avoiding or minimizing hazardous waste
generation such as the following:

    Proper  choice  of   foreign
    technology to ensure  better raw
    materials,  operations   and
    maintenance procedures.

    Recycling of waste into beneficial
    by-products.

    On-site treatment  of  waste for
    mass  reduction,   dewaterin^,
    detoxification  or change into an
    immobile and/or  chemically  inert
    form.

    The  second  step of the control
system  should aim at  licensing
procedures  for potentially  hazardous
activities.   This   means  that all
places  where hazardous waste is
stored,  treated or disposed  of  should
require  a  license  which  should be
obligatory  by  law.

    The  third essential  step  is a
comprehensive  system  of notification
establishing a link  between the
different  activities.
                     The  above  managment plan can be
                  used,  not only in Egypt,  but in all
                  developing countries where the concept
                  of  industrialization  is  highly
                  appealing with no precautions for its
                  hazardous wastes.

                  Supporting Literature
                  1)
                  2)
                  3)
Proceedings of  the  1980  National
conference   on  "Control  of
Hazardous  Material  Spills"
Louisville,  Kentucky,  May  13-15,
1980.   Nashville, TN, Vanderbilt
University.
"Management  of
WHO  Regional
European Series
 Hazardous Waste",
 Publications,
No.  14, 1983.
Curi,  K.,  ed.  "Treatment  and
Disposal  of  Liquid and  Solid
Industrial Wastes:  Proceedings of
the   Third  Turkish-German
Environmental   Engineering
Symposium,  Istanbul, July 1979,
Oxford,  Pergamon Press.
                  4)  Siltig,  M. "Landfill Disposal of
                      Hazardous  Wastes  and  Sludges",
                      Park  Ridge,  NJ,  Noyes  Data
                      Corporation,  1979.

                  5)  Treatment  of Hazardous  Waste.
                      Washington,  DC,  US Environmental
                      Protection Agency,  1980.

                  6)  Hamza  A. "Management of Industrial
                      Hazardous  Wastes  in  Egypt".
                      Industry  and Environment  Special
                      issue-No.  4, 1983, published by
                      UNEP.
                                 Disclaimer

                    The work described in this paper was
                    not funded by the U.S. Environmental
                    Protection Agency.  The contents do
                    not necessarily reflect the views of
                    the Agency and no official endorse-
                    ment should be inferred.
                                   191

-------
             NATURAL GEOCHEMICAL ATTENUATION OF CONTAMINANTS
                       CONTAINED IN ACIDIC SEEPAGE

                             Jim V. Rouse
                      J.H. Kleinfelder  & Associates
                           Denver, CO  80222
                         Roman Z. Pyrih, Ph.D
                    Roman Z. Pyrih & Associates,
                           Golden, CO  80401
       Inc.
                               ABSTRACT

Present-day  environmental  regulations  require  that waste disposal
facilities  be designed and engineered with  redundant  seepage-control
systems.   Despite the best efforts,  there is a possibility of contaminant
loss from such facilities.   In this case,  natural  retardation mechanisms
will be important in controlling the migration of pollutants.

A  conceptual  geochemical   model  has been  developed  to  explain  the
interaction of acidic  seepage with natural soil  materials.  The model  is
based  on  numerous laboratory tests and  field investigations  of  the
saturated  and vadose  zones at  uranium,  copper,  and phosphate milling and
processing  sites  throughout the United  States, Canada, and Australia.
Principal geochemical  reactions are identified and case histories  are
presented to illustrate the  degree of natural  control  on contaminant
migration.

Based on the observed,  predictable  order of contaminant migration, it is
possible to develop  a cost-effective system of phased monitoring which
incorporates  the geochemical  model,  reduces  the monitoring parameters, and
yet  provides equal  or greater  levels of  environmental  protection.
Suggestions  for such a monitoring program are advanced.
INTRODUCTION AND PURPOSE

     Present-day hazardous waste
regulations  require that waste
disposal  facilities be  designed
and  engineered with  redundant
seepage-control  systems.   The
best engineered facilities are
not truly "impermeable" and can
develop leaks over  long  periods
of waste containment.  When the
leaks  occur,  the  natural
retardation mechanisms provided
by underlying soils,  sediment or
bedrock will  constitute  the
control  on   the  spread  of
hazardous constituents contained
i n the waste.
                                   192

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     Many  hazardous wastes from
mininq,  milling, and processing
operations are acidic solutions
which  are  generated  by the
reaction of mineral acids such  as
sulfuric  acid  with  a  raw
material.  When such acidic waste
escapes  from  a  containment
facility  and penetrates the
underlying soil  or sediment,  a
complex series of  geochemical
reactions can he  initiated  which
may  immobilize  many  of the
hazardous  constituents  in the
waste.  Laboratory and field
studies  have provided valuable
information on  the  various
geochemical reactions which take
place  and  on  the  relative
importance  of each  of these
reactions.   The  studies have
shown that  predictions can  be
made  about  the rate of advance  of
various contaminants. The  pre-
dictions  are based  upon the
chemical properties  of the waste
solution and upon the geochemical
properties of the  underlying
geological  material.   Relying
upon this  predicted order  of
contaminant migration,  monitoring
programs can be developed  which
provide for a more cost-effective
as wel1 as  a more environmental ly
sound monitoring  scheme  which
utilizes  the more rapidly
advancing  constituents to alert
the operator of  the need for
increased monitoring efforts.

     This paper describes some  of
the  important geochemical re-
actions that take place, presents
a conceptual model  for the
interaction of acidic  seepage
with  natural  material,  and
provides suggestions for a phased
monitoring  program  which
recognizes that neochemical at-
tenuation  is likely to occur  to
some  extent in all natural media.
GEOCHEMICAL PROCESSES

     Numerous investigations have
provided  insight into the
geochemical processes that are  at
work  when  acidic  seepaqe
penetrates the subsurface.   An
excellent description  of the
ground water mobility of various
contaminants  is  provided  by
Cherry ,Shepherd, and Horin (1).
Another discussion of contaminant
migration, as  it relates to the
phosphate industry, is  provided
by  Rouse  and  Bromwell  (2).
Numerous investigations  have been
published for  uranium, base
metal,  precious  metal, and
phosphate operations throughout
the United States and Canada (3,
4, 5, 6).

     The  geochemical processes
that  are  at  work  as acidic
solutions come in contact with
natural materials are extremely
dynamic.   Some of the reactions
tend to remove  contaminants,
while others  exchange one
contaminant   for  another,   or
actually add contaminants into
the flow  system.  These dynamic
processes  must   be   better
understood before water-quality
data can be correctly interpreted
or before effective remedial
measures can be designed.

     By  far,  the  single most
significant geochemical process
that takes place between acidic
seepage and natural  materials  is
the reaction and dissolution  of
carbonate  minerals.   Hydrogen
ions in the acidic solution will
react  with calclte or  other
carbonate minerals which may  be
present in the underlying soil,
sediment, or  bedrock.    In the
course  of  the  reaction,   hydrogen
ions are  consumed  to  form
                                 193

-------
bicarbonate  and  the acidity of
the seepage is neutralized.

     Calcite  dissolution and acid
neutralization can trigger a host
of geochemical  reactions.  These
reactions can effect  not only the
quality of ground water, but also
the geotechnical  properties of
the  subsurface.   For  example,
dissolution of calcite introduces
calcium  ions into  the  seepage
system.   If the seepage solution
is enriched in sulfate content,
secondary sulfate  minerals  such
as  gypsum  or  anhydrite  may
precipitate.   Since secondary
qypsum occupies more  volume than
the previously dissolved calcite,
a reduction  in subsurface  per-
meability may  occur.

     On  the  other  hand,
neutralization of an  acid seepage
will  establish  pH conditions
which  are  favorable  to  the
functioning  of geochemical
mechanisms such as  ion-exchange,
sorption, and precipitation which
tend to remove potential  ground
water contaminants from solution.
Precipitation  of heavy metal
hydroxides is one  mechanism which
is initiated   by the calcite
dissolution  and  acid  neutral-
ization process.    The  pre-
cipitation is pH  dependent  and
has been studied  by  a number of
investigators.   Rouse (7)  pre-
sents a summary of  the  process
and describes  how  various metals
are sequentially removed as  a
result of increasing  pH.  Iron is
the earl iest  metal hydroxide to
be precipitated with increasing
pH,  followed  in turn  by aluminum,
copper,  zinc,  and finally
manganese.   In a  recent  ground
water investigation of the Globe-
Miami area of Arizona, several
such  sequential precipitation .pa
plumes have  been  observed
downgradient  of the  local mining
operations  (8).
EVIDENCE
ATTENUATION
FOR  C.EOCHEMICAL
     Many studies have provided
data on the qeochemical reactions
that have been described above.
This source of data  comes  from
column test results obtained in
the  laboratory  and from field
investigations of  actual  contam-
ination sites.

Column Test Results

     Column tests, such  as  the
one  depicted  in  Figure 1,  are
often  conducted  in  order  to
predict  what   geochemical
interactions will  occur between a
certain waste solution  and  the
natural   materials   that   the
solution  may  contact.  The
  <•* •IAHITI1I
  ~ 1**
            cy
            A  J* """"— *«ti»»*i. pua tamf MM
                        QkAV MAIMUb
                   II* »• 4* »M«I
 Figure 1.  Laboratory column experiments
         to predict geochemical inter-
         actions between waste solutions
         and natural materials.
                                  194

-------
objective  of the column test is
to percolate the waste  solution
through the natural material,  to
collect and analyze the  effluent,
and to compare the composition of
the effluent with  the  original
composition  of  the waste sol-
ution.

     Chemical and  radiological
analyses of two effluent samples
from  a  series  of   column
experiments are presented  in
Table 1.  The data  serves  to
illustrate the  functioning  of
geochemical  reactions which  tend
to remove potential ground water
contaminants  from   a  waste
solution.

     Both columns from  the test
series were  packed with very
similar  clay-bearing material,
and both  columns were exposed  to
the  same acidic waste from a
uranium mi 11 ing operation.  The
effluent samples whose composi-
tions  are profiled in the table
represent about the fifth pore
volume of waste solution through-
put.   The principal difference
between  the  shale  material   in
column  A and in column B  was
calcium carbonate content.  The
shale material in  column A was
highly calcareous, and capable  of
effectively neutralizing the
acidic pH of large volumes  of
uranium mi 11-waste  solution.   By
neutralizing the  acidity, optimum
pH conditions are established for
geochemical  removal  of ions from
solution.   Many  of the geo-
chemical mechanisms are most
active in a pH  range of 4.5 and
9.0.

Field  Investigation  Results

    A  number of  investigators
have described the  reactions of
acidic  seepage  with  natural
materials  downgradient of a
contamination source.  These
 TABLE 1. ANALYSES OF EFFLUENT SAMPLES
        FROM TWO COLUMN TESTS
• "™ — "" '" ------- - - -
CONSTITUENT
COLUMN
A
COLUMN
B
URANIUM
WASTE
 Effluent pH  7.7     3.5     1.8

             Concentration (g/1)
S04
HC03
Na
Ca
M9
Al
Si (In mg/1)
As
Cu
Fft
Mo
Pb
Se
V
2n
U3°8
Ra 226
Th 230
Pb 210
Po 210
12.4 19.7
1.6 0.0
3.42 3.37
0.38 0.48
1.42 2.22
0.0 0.42
7.9 37.
Concentration
0.12 0.28
0.07 14.9
0.44 338.
<0.10 <0.10
<0.02 <0.02
0.14 0.14
<0.10 83.5
0.13 6.9
0.32 1.47
Concent ra t i on
25.6
0.0
3.40
0.55
1.52
1.01
57,
(rag/D
1.51
34.5
762.
2.89
1.0
0.24
SOI.
5.5
3.88
(pCi/1)
0.2±0.3 9,1*2.3 63t7
2.7*5.3 3900±200 82000*1000
0.0±4.6 4.7*3.9 193013Q
0.8±3.9 8.0±12 3300*200
III 1 TIN
investigations clearly support
the findings of  laboratory column
tests.

     One  of the most extensive
geohydrological  and geochemical
investigations focused on  a 500
square  mile area in  eastern
Arizona which  was impacted by
contaminant migration  from
natural mineralized  areas and
from extensive copper  mining and
milling operations  (8).  Since
the water-bearing bedrock con-
tained  low  concentrations of
                                  195

-------
carbonate  minerals, an extensive
contamination plume  was  formed
downqradient of the source of the
contamination.  Such  an  exten-
sive, elongated plume  enabled the
definition of various contami-
nation  zones. Pumping a  non-
contaminated aquifer  underlying
the contamination plume resulted
in the migration  of contaminants
into  the  producing  aquifer.
Chemical  breakthrough  of various
constituents into the producing
aquifer was  in accordance with
the order  of appearance predicted
in the column tests.

     Recent monitoring  near gold-
mill tailings in South Dakota has
indicated  that a  similar order of
contaminant  appearance  is  in
effect in  unsaturated as well  as
saturated zones.

     Investigations  of a  man-
induced perched  water system
underlying an acidic uranium mill
tailings pond in western Colorado
confirmed  the existence of  acidic
water similar in composition to
seepage  that  had   undergone
geochemical modification (9).

     An evaluation   of  radio-
nuclide migration  below the base
of  an Australian  uranium mill
evaporation  pond  displayed a
strong positive  correlation
between radionuclide  content and
the acidity of the  material.
This allowed for  the  development
of  a rapid  field inspection
technique which  can  be used in
reclamation efforts,  without the
need for time-consuming labora-
tory assays (10).

     At another uranium mi 1 1 in
eastern Washington  state,  monitor
wells  within  100  feet  of  a
tailings  pond did not  detect
elevated  levels  of  metals or
 radionueTides,  despite a  seepage
 rate of  approximately 1500 to
 2000 gpm  over a 20 year history.
Downgradient  wells  contained
lower radium  concentrations than
upgradient wells, as a result of
gypsum precipitation and radium
coprecipitation (11).

During  an investigation of ground
water quality downgradient of a
series  of  seepage   ponds,  data
were generated which displayed an
orderly progression of  contam-
inant  attenuation.  Radium
contamination was not above the
EPA  Drinking  Water Standards,
even in a monitor well  drilled on
the  berm separating two of the
ponds (12).   Table 2 illustrates
the  range of  chemical quality,
and the sequential  attenuation of
contaminants for various  wells.
CONCEPTUAL  MODEL

     The findings and conclusions
from the various  investigations
described  above  provide suf-
ficient background to develop a
conceptual  geochemical model for
 TABLE 2. ANALYSES OF GROUND WATER SAHPLES FROM
       HELLS ALONG SEEPAGE PLUHE,  SHOWING
       SEQUENTIAL CONTAMINANT REMOVAL

CONSTITUENT
pH

ins
Bicarbonate
Sulfdte
Chloride
Sodium
Potassium
Calcium
Ha qnes 1 urn
Iron
Hannanese
Zinc
Copper
Cadmium
Nitrate
Ammonium
Uranium
HELL
CRP-8
3.45
Concentration
146000
0
83600
5230
6300
23
230
16000
2900
510
220
27
6.7
20
549
11
HELL
CRP-8
6.3
, nq/i
26100
1970
18400
1310
970
180
530
3500
0.15
23
1.1
0.04
0.01
145
760
0.6
WELL
CRP-B
6.75

7640
805
5190
354
270
94
270
780
0,07
2.7
0.48
0.02
<0.01
40
383
0.18

                                   196

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          Qroundwater Movement
                               Neutralizing Zone) —
                             Active Gclclte Dleeolutlon,
                               M*««I* Precipitation
   Acid Zone -
Hlflh Metal* Concentration
  Neutralized Zone -
•eturated Qypautn Solution.
 MeteU At Hydroxide
 Solubility
  Figure 2.   Conceptual model of geochemical zones in  a contaminant  plume.
contaminant  movement  and im-
mobilization.  This conceptual
model  is  similar to the model
which was suggested  by  Cherry,
Shepherd, and Morin  (1) and  is
based  on  the results  of  many
laboratory column tests,  as  well
as on the field experience of the
authors at uranium,  phosphate.,
copper,  and  gold mining  sites
throughout the  United  States,,
Canada,  and Australia.

     As  an   acidic   waste
percolates into the subsurface,
qeochemical  process begin  to
occur  at  the advancing  front.
Calcite dissolution and   acid
neutralization result in  a  move-
ment  of the reaction  front.
Depending upon  the  calcite
content  of the natural subsurface
material, the  acid front  is
slowed,  and retarded in its  down-
gradient movement relative to the
rate of the fluid travel.  The
advance  of the  acid  front  is
controlled  by  the number  of pore
volumes  of   acid  water   that
must react with a given volume  of
porous  media to  completely
dissolve all of the calcite.

     In   effect,   as   the
contaminant plume proceeds  down-
gradient,  a total  of  three
distinct zones  will develop
(Figure  2).  The first zone,  which
                            may be  termed  the "acid"  or
                            "core" zone, consists of ground
                            water with a quality virtually
                            identical  to  that  of the source
                            of  the  seepage.   The  water is
                            characterized by extremely low
                            pH, very  high  sulfate  ion
                            concentrations,  and  contains
                            numerous heavy and  toxic  metals.
                            In  the acid or core zone al1 of
                            the carbonate minerals present in
                            the soil or  bedrock  have been
                            dissolved. In  soil  or bedrock
                            which  is   high in carbonate
                            content,  the  acid  or core zone
                            often  is only  a few meters in
                            extent.   Well  CRP-8 (Table 2) il-
                            lustrates a well within the acid
                            zone.

                                The  second  zone  in the
                            conceptual  model  is termed the
                            "neutralizing zone" and is the
                            area   of  active  calcite
                            dissolution and the formation of
                            chemical precipitates including
                            gypsum  and  the  heavy  metal
                            hydroxides  and carbonates.  Water
                            in  this  zone is  characterized by
                            high  levels  of some  dissolved
                            metals, in accordance with the
                            sequence  of metal hydroxide
                            removal.  The  types  of metals
                            present can be directly related
                            to the resultant  pH  of the
                            solution.   Wei 1 CRP-6 (Table 2)
                            is a well located near the middle
                            of a neutralizing zone.
                                 197

-------
     Downgradient   of  the
 neutralizing zone  is an  area
 which   can  be  termed  the
 "neutralized" zone.   Water in the
 neutralized zone is characterized
 by high concentrations of total
 dissolved solids,  and is  fre-
 quently saturated with  respect to
 gypsum.   Little, if  any, calcite
 dissolution  occurs  in  the area.
 Virtually all of   the calcite
 originally in the soil  or bedrock
 remains available for  reaction.
 Well CRP-14 (Table 2) is close to
 the boundary between  the neutral-
 izing and neutralized zone.

 PHASED MONITORING APPROACH

     The accepted approach  to
 monitoring is to analyze for a
 large  number of  constituents.
 Since  there  is a  logical  and
 predictable  order   for the
 appearance of contaminants as the
 contaminant plume advances, it is
 possible to design and  operate a
 cost-effective monitoring program
which recognizes  that geochemical
 attenuation can occur and limits
 the number of constituents that
 are analyzed.  Such a monitor!nq
program  can concentrate  on
 identifying critical  constituents
to alert the operator of the need
for increased efforts.   In the
area  of  the neutralized  zone, the
 initial  monitoring should consist
of major ion  analyses,  with
special  attention  directed  at
sulfate and total  dissolved
solids.   There  is  no  rational
basis for heavy metal analyses so
 long as the water chemistry  of
the ground water is typical  of
background or of the neutralized
zone.

     The sequential  order  of
contaminant appearance  predicts
that  manganese and zinc wi1 1  be
the first  of  the  common heavy
metals  to  appear,  followed  in
turn  by  copper,  aluminum, and
finally  iron.  For this reason,
                                  198
once the sulfate concentrations
indicate the  proximity of the
neutralizing  zone,  monitoring
should begin  for manganese and
zinc.   Only  when  these  con-
taminants appear,  the monitoring
program should  be  expanded to
include other metals such as iron
or copper.

     There are several  important
advantages  of  the  phased
monitoring approach.  The program
can  be  designed  to   be  site
specific, taking  into consider-
ation the chemical properties of
the waste solution as well  as the
geochemical  properties of the
underlying  geological material.
The phased   monitoring  approach
can  be cost effective and can
quickly generate water-quality
data  that   are  meaningful and
instructive.

REFERENCES

1.   Cherry, J.A., Shepherd, T.A,
     and  Morin,  K.A.,  February,
     1982, Chemical Composition
     and Geochemical Behaviour of
     Contaminated Groundwater at
     Uranium Tailings  Impound-
     ments.   Preprint No. 82-114,,
     Sgc.  of Mining Engineers  ^
     "ATME Annual Meeting, Dallas.

2.   Rouse,  J.V.,  and Bromwel1 ,
     L.G.,  March, 1983,  Waste
     Sources and  Impacts of Waste
     Disposal  on  Area  Water Re-
     sources,  Florida Phosphate
     Industry. Preprint 83-510,
     Soc. ofMining  Engineers
     AIHE     Annual	Meeting,
     Atlanta.

3.   Taylor  M.J.,  and Antonmaria,
     P.E.,   November,  1978, Im-
     mobilization of  Radionu-
     clides of Uranium Tai1 ings
     Disposal  Sites.   Symposium
     on  Uranium  Mill   Tailings
     TTanagement,   Colorado  State
     University.

-------
9.
10.
     Rouse,  J.V.,  1974,  Radio-
     chemical  Pollution  from
     Phosphate Rock Mining and
     Milling, Mater    Resource
     Problems Related to Mining,
     Am,   Hat.  Resources  Assoc'.,
     Minneapolis.p.65-71.

     Mil ler, R.L.,  and Sutcliffe
     H.,Jr.,  April   1982,  Water-
     Quality and Hydrogeologic
     Data for  Three Phosphate
     Industry  Waste-Disposal
     Sites in Central  Florida,
     1979-1980.  U.S.  Geological
     Survey  Water-Resources"^'Iri-
     yest i ga t i ons  81-84,  Ta11 a-
     hasseT FL; p.  84.
Wissa, A.E.Z., and Fuleiham
N.F., November 1980, Control
of Groundwater Contamination
from Phosphogypsum Disposal
Sites.  Proceed ings of  the
InternatTbhaTSymposium  on
Phosphogypsum, p.  482-539.

Rouse  J.V.,  October  1976,
Removal of Heavy Metals from
Industrial  Waste.   ASCE
Journal  of the EnvironmentaT
Engineering  Pivisipn.  Vol.
102,  No EES.  Proc.  Paper
12447,  p. 929-936.

Envirologic  Systems,  Inc.,
May 1983,  Mining  Activities
and Water Quality Reports,
METF-7, for Centra 1 Ari_zon_a
Association of Governments.

Rouse, J.V., and Pyrih R.Z.,
1983,  Summary  Report  on
Geohydrological and Geochem-
ical Conditions, with Recom-
mended Ground-Water Monitor-
ing Program, Uravan, CO.
En viro logicSystems,    Inc.
for UnionCarbide  Corp..

Rouse, J.V.,  February 1981,
Vertlcal   Mobi1ity  of
Radionuclides   at  Mary
Kathleen, Queensland (Aus-
                                      tralia)   Uranium  Mill
                                      Evaporation Pond  No.  2.
                                      Enviroloqic  Systems,   Inc..
                                      for Golder Associates.

                                  11.  Rouse, Jim V., December 1983,
                                      Report on  Water  Quality
                                      Investigation, Club  Ranch
                                      Ponds  and Atkinson  Crystal
                                      Area,    Uravan,    CO.
                                      Enyirplogic Systems,  Inc. for
                                      Union Carbide Corp.
12.   Wilson  L.C.,  and Rouse,
     J.V.,  May 1980,  Geohydro-
     logical  and Geochemical
     Evaluation of Existing and
     Potential Contaminant Trans-
     port from Dawn Mining Co.,
     Tailings  Pile,   Ford,  WA.
     En v irol ogl c  Systems,   Inc.,
     for Dawn Mining Co..
              Disclaimer

 The work described in this paper was
 not funded by  the U.S. Environmental
 Protection Agency.  The contents do
 not necessarily reflect the views of
 the Agency and no official  endorse-
 ment should be inferred.
                                   199

-------
        PETROLEUM REFINERY  SOLID  WASTES:   WHAT  WILL  WE  DO  WITH  THEM?

                        Wayne C.  Smith, Ph.D.,  P.E.
                           Executive  Consultant
                            Kellogg Corporation
                           Littleton,  CO   80121
                                 ABSTRACT
     The objectives of this paper are to (1) provide an overview of the
SPA Refinery Waste Characterization Study and the American Petroleum
Institute (API) oversight program, (2) discuss some of the possible rami-
fications of the 1984 Resource Conservation and Recovery Act (RCRA) and
possible new hazardous waste regulations, and (3) discuss some possible
avenues that may be available for reducing the impacts of the potential
new regulations.

     Certain petroleum refinery wastes are listed by RCRA regulations,
part 261.32 as hazardous wastes.  These wastes are:  (1) dissolved air
flotation float (DAF) - KQ48j (2) slop oil emulsion solids - K049; (3)
heat exchange bundle cleaning sludge - K050; (4) API separator sludge -
K051; and (5) tank bottoms (leaded) K052.  Waste streams K048, KQ49 and
K051 are listed as hazardous because they contain hexavalent chromium and
lead.  Waste K050 is listed because it contains hexavalent chromium and
K052 is listed because it contains lead.  Other refinery wastes are
hazardous only if they fail the Extraction Procedure (EP) toxicity test.

     Some refineries dispose of these wastes by land treatment and are
required to have a Part 264 Part B permit, and this permit requires that
the Appendix ¥111 hazardous constituents be identified.  The Office of
Solid Waste is conducting a Refinery Waste Characterization Study.  The
major emphasis of this study is to identify waste characteristics of
approximately 35 refinery waste streams (several of which are not cur-
rently hazardous waste) so that the results can be used for evaluating
delisting petitions and Part B permit applications, and possibly for
developing new hazardous waste regulations.

INTRODUCTION AND PURPOSE              261 (1), listed certain petroleum
                                      refinery wastes as hazardous
     The Resource Conservation        wastes.  The wastes are:   (1)
and Recovery Act (RCRA) regula-       dissolved air flotation float
tions issued May 19, 1980, 40 CFR     (DAF)-K048;  (2) slop oil emulsion
                                   200

-------
solids - KQ49;  (3) heat exchange
bundle cleaning sludge - K050;
(4) API separator sludge - K051;
and (5) tank bottoms  (leaded) -
K052.  Waste streams  KQ48, K049
and K051 are listed as hazardous
because they contain  hexavalent
chromium and lead.  Waste K050 is
listed because it contains hexa-
valent chromium and K052 is
listed because it contains
lead.  Other refinery wastes are
hazardous only if they fail the
Extraction Procedure  (EP) toxic-
ity test.d)

     The Environmental Protection
Agency (EPA) began conducting a
Refinery Waste Characterization
Study of waste streams generated
at petroleum refineries in
October 1983.  The purpose of the
EPA study is to characterize the
five waste streams currently
listed by RCRA regulations as
well as other candidate streams
that may contain hazardous sub-
stances and develop a data base
to assist in evaluating delisting
petitions submitted by refin-
eries.

APPROACH

     Most, if not all, petroleum
refineries have submitted delist-
ing petitions, for the five waste
streams listed in 40  CFR 261, to
the EPA because the concentration
levels of hexavalent  chromium and
lead,  as detected by  the EP tox-
icity test, are far below the
limits specified by 40 CFR 261.
The EPA decided that  they needed
more data to evaluate these
delisting petitions and that pos-
sibly other chemical  parameters
(metals and organics) should be
evaluated to determine if refin-
ery wastes should be classified
as hazardous wastes.  At the pre-
sent, refinery wastes, other than
the five listed wastes, can be
disposed in a non-RCRA waste dis-
posal facility.

     In October 1983, the EPA
contractor began the Refinery
Waste Characterization Study.
The American Petroleum Institute
(API) hired a contractor to over-
see and evaluate the EPA study
and conduct a parallel analyses
program.  The purpose of the EPA
study is to identify potentially
hazardous constituents in
approximately 35 (Table 1) refin-
ery waste streams (several of
which are not currently hazardous
waste).  The Agency wants to
classify the hazardous organic
compounds in the refining wastes
to determine if these wastes
should be declared hazardous
because of the organic compounds.

     Eight refineries were selec-
ted and preliminary sampling and
analyses were conducted on some
or all of the waste streams
listed in Table 1.  Based on this
preliminary testing, the Agency
is considering whether to rede-
fine the standards for regulating
dissolved air flotation float and
leaded tank bottoms based on
their possible hazardous organic
constituents as well as their
metal content.  The EPA also will
determine whether to list refin-
ery wastes in addition to the
five types now regulated under
RCRA.  Additional sampling and
analyses will be necessary before
the EPA makes any final decision.

     The waste listing studies
were mandated by Congress in the
1984 RCRA amendments.(2)  These
amendments require the EPA to
issue by November 1986 rules
broadening the basis for
                                    201

-------
 regulating wastes  based on  their
 constituents  and to  complete
 action by  November 1986 on  all
 delisting  petitions  requesting
 wastes be  removed  from RCRA
 controls.

     The analytical  program con-
 ducted by  EPA and  API  contractor
 varied considerably  from the past
 EPA  Office of Solid  Wastes
 approach of analyzing  refinery
 wastes for EP toxic  metals.
 While  the  past  interest in  the
 five wastes currently  listed has
 been chromium and  lead from the
 EP toxic extracts, the new  analy-
 tical  plan is far  more
 extensive.  Past experience  has
 indicated  that  the current  EP
 toxic  procedure does not ade-
 quately evaluate metals in  oily
 wastes; therefore, a new oily
 waste  extraction procedure  was
 developed  and the  extract was
 analyzed for  both  EP toxic  metals
 and  total  metals.    All samples
 were analyzed for  a  group of 12
 metals  and 95 organics.  Several
 of the  organic  compounds could
 not  be  analyzed using  existing
 techniques; therefore,  new  tech-
 niques  were developed  and will be
 published  in  the near  future.
 The  samples were analyzed for
 total as well as EP  toxic metals
 using  the  new oily waste extrac-
 tion procedure.  Emphasis may be
 placed  on  total metals  rather
 than oily waste  EP toxicity  dur-
 ing  data evaluation  by  the EPA.
 The  new oily  waste procedure
 removes all water  and  oil from
 the  sample before performing the
 existing extraction  procedure.
 The  EP oily waste  test  result"
 consists of the  composite analy-
 ses  of  the aqueous,  oil  and  solid
 fractions.  The  organic  analyses
measured the  total concentration
 of the  95  organic  chemicals  in
 the  samples.
     The results of the analyses
described above will be used to
determine if the five waste
streams currently listed will
remain listed.  Some of the other
waste streams (Table 1) may be
listed as a result of this
study.  Considering the complex
and extensive analyses that were
performed, it was of the utmost
importance that the samples col-
lected be representative of the
waste streams under study.  The
EPA contractor collected all
samples under the observation of
the API contractor and refinery
personnel.  Samples were split
and analyzed by the EPA and API
contractors.  Results"of this
study are expected to be pub-
lished by the SPA in the near
future.  These results are not
available at this time.

     Many refineries dispose of
their wastes by land treatment
and are required to have a 40 CFR
264 Part B. Permit and this per-
mit requires that 40 CFR 261,
Appendix VIII hazardous constit-
uents be identified.  The
Appendix VIII list contains most
organic chemicals known to man.
In April 1984, an EPA memo(3)
presented a list of Appendix VIII
hazardous constituents suspected
to be present in petroleum refin-
ery wastes and a special analyti-
cal method for refinery wastes.
The wastes listed are essentially
the 12 metals and 95 organic
chemicals analyzed during the EPA
Refinery Waste Characterization
Study.

     This memo states "Because
the design and management of a
land treatment unit is based on
the goal of attaining treatment
of hazardous constituents (i.e.,
constituents listed in Appendix
                                   202

-------
¥111), it is very important  that
the presence of the constituents
in the land treated wastes be
accurately identified and quanti-
fied.  This is best achieved
through a comprehensive waste
analysis for all Appendix VIII
constituents.  However, due  to
the cost and analytical diffi-
culties associated with these
analyses, many applicants have
submitted requests to conduct
analyses for some subset of
Appendix VIII, which are 'reason-
ably expected to be in or derived
from the wastes to be land
treated.'  To date, the majority
of the wastes proposed for land
treatment have been petroleum
refinery wastes, specifically the
listed wastes KQ48-KQ52."

     The list provided in this
memo is to be used until the
results of the EPA study are
available.  This list is the same
information that the EPA recently
requested from all delisting
petitioners.

PROBLEMS ENCOUNTERED

     Two major problems were
encountered during the course of
the EPA study.  These were:  (1)
development of a new extraction
procedure for oily wastes and (2)
development of analytical techni-
ques sufficient to analyze for
the 95 organic compounds.

     A third problem exists for
industry that is required to con-
duct the analysis for delisting
or a Part B permit.  The analyti-
cal techniques developed during
the EPA study are not published
and only two or three labora-
tories in the U.S. are currently
able to use these techniques.
Also, the cost of conducting
these analyses are expensive
($1,500 to $2,500.per sample).

RESULTS

     Results of the EPA Refinery
Waste Characterization Study are
not available at this time.  How-
ever, recently published data(4),
obtained using these techniques,
indicates that refinery waste-
water sludges, as well as sludges
from API separators and DAF units
contain toxic organic constitu-
ents including benzene, toluene,
benzo(a)pryene, ohrysene and
pyrene.  These data were the
result of a delisting petition;
however, one can assume that the
results of the EPA study will
identify the same and possibly
more constituents that are toxic
and cause more refinery wastes to
be controlled by RCRA.
             Table  1

    .LIKELY WASTE STREAMS FOR
EVALUATION IN REFINERY INDUSTRY
STUDYCa'

  Wastewater Treatment Residuals

    o Sludges Generated in the
      Gravity or Chemical Treat-
      ment of Refinery Waste-
      waters
    o Air Flotation Unit Float
    o Biological Treatment
      Sludges
    o Heat Exchange Bundle Clean-
      ing Sludge
    o Flow Equalization Basin
      Sludges

         Slop Oil Recovery

    o Slop Oil Emulsions
    o Slop Oil Tank Bottoms
                                    203

-------
      Storage Tanks

o Crude Storage Tank Bottoms
o Gasoline Storage Tank
  Bottoms
o Clarified Oil Storage Tank
  Bottoms

   Lube Oil Production.

o Spent Solvents (especially
  Phenol,  Demex, Di-Me and
  Other Chlorinated Hydro-
  carbons )
o Solvent Rich Condensates
o Treating Clays

    Catalytic Cracking

o Spent Catalyst
o FCC Fines
o Clarified Oil Sludge

  Other Solid Catalysts

o Hydrocracking
o Polymerization
o Hydrorefining and Hydro-
  treating
o Merox

      HF Alkylation

o Spent Caustic
o Spent Bauxite
o Acid Soluble Oil and Tars
o Alkylation Sludge

          Coking

o Coke Fines and Scrubber
  Sludges
o Purge Coke

     Product Treating

o Liquid Merox
o Caustics - Phenolic and
  Sulfidic
o Doctor
     DeSalter Cleanout Sludge

          Treating Clays

    o Lube Oils
    o Pyrotol
    o Jet Fuel

        Tail Gas Treating

    o Spent Stretford
        Distributed by OSW on
February 29, 1984
     Once the EPA study is com-
pleted, it is likely that addi-
tional regulations will be pro-
posed to further control the dis-
posal of refinery wastes.

     At a very minimum, all
petroleum refineries will have to
reevaluate the information devel-
oped for their RCRA Part B permit
application.  This will probably
result in a new costly sampling
and analysis program and cause
long delays in obtaining the per-
mit,

     A recently published draft
manual (5) on Land Treatment
Demonstrations required by 40 CFR
270 indicates that a land treat-
ment demonstration will be
lengthy and costly to refiners.

     The fact that more waste
streams may be controlled by
RCRA, the problems with getting a
land treatment Part B permit and
by the fact that the 1984 RCRA
amendments (2) specifies that
certain wastes be prohibited from
land disposal in the future and
that generators must submit
reports every two years that des-
cribe the quantities, nature and
disposition of the hazardous
wastes generated, the efforts
undertaken to reduce the volume
                                204

-------
and toxieity of wastes, and the
changes in volume and toxicity
achieved from the previous years
make it imperative that petroleum
refiners and researchers continue
their efforts to reduce the tox-
icity and volume of wastes.

     Considerable research and
development have been conducted
in waste solidification.  Solidi-
fication can minimize the amount
of liquid present and assist in
reducing the leachate problem.
However, this method does not
reduce the volume of waste.  It
may make the waste non-hazardous
but may even increase the volume
of waste to be disposed.
     Incineration has been in use
for certain wastes but some
wastes have not been successfully
incinerated because of equipment
problems.  Most incinerators used
in the U.S. are designed to
incinerate only liquids; however,
rotary kiln technology has been
used successfully in Europe for
several years and may be a poten-
tial partial solution to dispos-
ing of refinery wastes.  Recent
research with circulating bed
incinerators (6) indicates poten-
tial.

     In conclusion,  new regula-
tions and industry's desire to
dispose of wastes in a cost-
effective and environmentally
safe manner pose some interesting
challenges for the next several
years and will require some dedi-
cated research and development.

         ACKNOWLEDGEMENTS

     The assistance of Kellogg
Corporation, management and staff
in the preparation of this manu-
script is greatly appreciated.
            REFERENCES

1.  Hazardous Waste Management
    System, Identification and
    Listing of Hazardous Waste
    Federal Register, 40 CFR 261,
    Vol. 45, No. 98, U.S. Envir-
    onmental Protection Agency,
    May 19, 1985

2*  Hazardous and Solid Waste
    Amendments of 1984, P.L. 98-
    616, November 1984.

3.  Skinner, John D., Guidance on
    Petroleum Refinery Waste
    Analyses for Land Treatment
    Permit Applications, U.S.
    Environmental Protection
    Agency, April 1984.

4.  Hazardous Waste Management
    System; Identification and
    Listing of Hazardous Waste
    Federal Register, 40 CFR Part
    261, Vol. 50, No. 28, U. S,
    Environmental Protection
    Agency, February 11, 1985.

5.  Evans, G. B., Jr., William
    Hornby and K. C. Donnelly,
    Draft-Permit Guidance Manual
    on Hazardous Waste Land
    Treatment Demonstrations,
    EPA/530-SW-84-015, USEPA
    Office of Solid Waste and
    Emergency Response,
    Washington, B.C., December
    1984.

6.  Rickman, W. S., et al, Circu-
    lating Bed Incineration of
    Hazardous Waste, Chemical
    Engineering Progress, p. 34-
    38, March 1985.

               Disclaimer

 The work  described  in  this paper was
 not funded by  the U.S.  Environmental
 Protection Agency.   The  contents do
 not necessarily  reflect the views of
 the Agency and no official endorse-
 ment  should be inferred.
                                   205

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             ULTIMATE CONTAINMENT OF RESIDUAL HAZARDOUS WASTE
                                 IN SALT FORMATIONS

                             Roger Blair and Fritz Crotogino
                                      PB-KBB Inc.
                                   Houston, TX 77079
ABSTRACT

     The major  theme of  hazardous waste
management today emphasizes the rendering
of hazardous waste into its neutralized or de-
toxified  components  through  a variety  of
treatment techniques. The  efficiency of the
available hazardous  waste  treatment pro-
cesses,   including incineration, biodegrada-
tion, chemical and physical alteration, are
less than perfect within economically accep-
table  limits.   The residual,  non-reducible
hazardous constituents of the treated haz-
ardous waste must be prevented from enter-
ing the biosphere.

     The permanent isolation of these resi-
dual, non-reducible hazardous waste constit-
uents can be accomplished  by encapsulation
in a matrix within a cavern or vault con-
structed in  salt formations.  The ability to
design and construct repositories in domal or
layered  salt  formations  is an  established
practice and is not extensively treated in this
presentation.   This  paper  summarizes the
concept  of  combining the proven technolo-
gies of both cavern (repository) development
by dissolution and waste solidification.  Be-
yond the theoretical advantages of this isola-
tion  technique, the paper reports on in-situ
experiments, conducted within  the  interna-
tional hazardous  waste community.   Actual
projects  in hazardous  waste disposal in salt
and closely related programs are also dis-
cussed.
INTRODUCTION AND PURPOSE

     The  recent environmental disasters at
Love Canal and  Times Beach served to focus
public  awareness upon the issues of hazard-
ous waste management.   Consequently our
elected officials undertook the revitalization
of the  environmental  laws by the enactment
of  the 1984  Hazardous  and Solid  Waste
Amendments to the Resource Conservation
and Recovery Act of 1976 (RCRA). The Act
now mandates the elimination or reduction of
hazardous waste by refining  production pro-
cesses  and the recycling of wastes. In those
instances  where the generation of hazardous
waste cannot be avoided, the hazardous con-
stituents are to  be detoxified, neutralized or
rendered nonhazardous by treatment prior to
disposal.

     Although  the  goals and  objectives of
this  new  legislation  are  to  be applauded,
RCRA  does not  provide for the disposition of
the hazardous  constitutents of waste  (like
heavy metals)  which cannot be rendered less
hazardous by treatment.  Clearly these non-
reducible  hazardous residuals must be man-
aged in order to protect human health and
the environment.   Placement of  hazardous
materials  in surface impoundments or landfill
facilities  is unacceptable and is  prohibited
under RCRA.
                                           206

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     The problems associated with the ulti-
mate disposal  of these hazardous residuals
very closely parallels the  difficulties of dis-
posing of untreatable and indestructible ra-
dioactive waste.  Based upon the best scien-
tific and engineering advice, the  Congress
identified  the  containment  of  radioactive
waste   in   underground  repositories,  con-
structed in geologically secure formations, as
being protective of human health and the en-
vironment,  when  they enacted  the Nuclear
Waste Policy Act of 1982 (NWPA).

     The ultimate disposal  of  the residual
constituents of  hazardous  waste by isolating
them from  mankind  and the  environment in
subterranean repositories constructed in salt
formations   is  environmentally  desirable,
technically  feasible and economically sound.
Public confidence, based upon an understand-
ing of the integrity afforded  by a system of
natural  salt barriers, is the  sole missing in-
gredient to the solution of the ultimate dis-
posal problem for  residual hazardous wastes.
APPROACH

Why Salt Is A Suitable Environment

     Salt, known as sodium chloride or as the
mineral halite, possesses several characteris-
tics that qualify it as a prime candidate for a
hazardous waste storage medium. First, salt
in its  native state is solid and very low in
permeability (the ability to transmit fluid).
This point is often overlooked due to the fact
that most of us only see salt after it has been
crushed into  the granular form we sprinkle on
food.  Salt is so low in permeability that for
all  practical purposes  it can  be considered
impermeable.  This is a critical factor  be-
cause the disposal formation must be able to
retain  the waste, and also, must not permit
external water to enter and migrate through
the waste.
      A second favorable  characteristic of
salt is its tendency to creep under rock pres-
sure.   Voids  occurring  between  the cavern
walls and the hazardous  waste mass placed in
salt will be minimized or closed due to this
behavior.   This visco-plastic material beha-
vior also contributes to  the low permeability
of salt by preventing fractures in undisturbed
salt rock.

      Additionally,  salt  is  strong enough to
withstand stresses experienced around a sub-
surface excavation, remaining fractureless to
a great extent (without any lining) because of
its  favorable mechanical behavior. The com-
pressive strength of salt exceeds that of con-
crete commonly used in construction.

      Many  are  aware  that  salt  dissolves
when exposed to water and fear the  salt for-
mation  will dissolve  and expose the hazard-
ous waste.  As mentioned earlier, salt is im-
permeable and will not permit the passage of
water.  Water meeting  the exterior  surface
of  a large  salt formation will dissolve the
outer edge  slightly, but will  stop as soon as
the water becomes saturated with salt. Pla-
cing  the  hazardous  waste deep  in  the  salt
formation will shield it from exposure by any
such  dissolution.   The  fact  that most  salt
formations  have been in place for over 200
million  years indicates that no major water
source has been in contact with the salt.

      Disposal in salt also  provides  the cost
saving  ability to store  mixtures of  waste
rather than segregated ones.   As long as the
mixtures of  waste are chemically  compati-
ble, they can be placed  in salt caverns with-
out being submitted to expensive  segregation
and separate  disposal methods.  There are a
few compounds that  must be excluded be-
cause they  react with sodium chloride, but
the majority can be safely deposited in salt.
In fact, ony a few compounds, such  as those
containing  lithium  or  bromine  trifluoride,
cannot be disposed of in salt (1).
                                            207

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     Another attractive  feature of salt is
the fact  that  salt deposits are located all
over the world, generally in areas of low tec-
tonic  activity (which  means  little  or no
chance of earthquakes).  Figure  1 illustrates
the location of major  salt deposits in  the
United States.(2)  As a rule, the deposits are
also massive in size.

     Bedded salt formations were deposited
in layers  that can be several  hundred  feet
thick.  These  layers are usually separated by
relatively thin deposits of  shale, a rock  that
also has  very  low  permeability.  Bedded salt
can be found throughout the world.

     Domal salt deposits are extremely mas-
sive in size.   An  average Gulf Coast salt
dome,  for example, is several thousand  feet
thick and underlies a surface area of a couple
of thousand acres. Salt domes can be found in
many parts of the  world, but are not as wide-
spread as bedded deposits.

     Salt deposits  range in age  from 2  mil-
lion  to 600  million years old, with the aver-
age being about 200 million years in age.
     Finally, an important  economic advan-
tage of salt as a safe environment for the
disposal of waste is its high solubility in wa-
ter.  As explained in the next section, subsur-
face space  can be created by above ground
controlled dissolving or leaching without re-
quiring mining  equipment or personnel work-
ing in the subsurface.

Construction Of A Cavity In Salt

     The alternative to conventional mining
- sinking mine  shafts into the salt formation
and excavating galleries by subsurface  drill
and  blast techniques  - is  solution mining.
This method takes advantage of some  of the
physical characteristics of  the salt.  It in-
volves the  injection,  via a drilled  well, of
fresh water  into a salt formation.  The water
dissolves or "leaches", the  salt.   This  salt
water, or brine, is removed from the cavern
by  displacement through  the  same drilled
well.  The  simultaneous water injection and
brine withdrawal  is accomplished by using
two  suspended  strings  of  tubing installed
concentrically  to one another and to the ce-
mented casing (Figure 2).
          Figure  1:   Location of major  salt deposits  in  the
                         United  States
                                          208

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   RAW WATER

        BRINE
    CAVERN
Figure 2.  Solution Mining Process
       (Schematics)
     As seen in Figure 2, the two suspended
strings provide three avenues for flow into,
or out of, the cavern.  The bottom two open-
ings are used for water injection and brine
production purposes.  The water can be in-
jected into the upper opening and the brine
can be withdrawn from the lower of the two,
or  vice  versa, depending  on  what  cavern
shape is desired.   Cavern shape is also af-
fected  by the  depths at which these two
openings are located.

      Further control  of cavern shape is at-
tained  by  injecting  & protective  medium
(blanket) into the cavern via the third, or up-
permost, opening.    The  result is  an engi-
neered  cavern that can be  classified  as a
permanent structure.  An illustration of a ty-
pical Strategic Petroleum Reserve (SPR) oil
storage cavern is shown in Figure 3.
Figure 3.  Typical SPR Oil Storage Cavern
       In a Gulf Coast Salt Dome
    (Cavern Volume = 11 million barrels)
     The access well will typically penetrate
water  bearing formations.  During drilling,
the well will be completed with several con-
centric casings that are cemented up to the
surface. Each casing string will be pressure
tested after it is installed to insure absolute
tightness.  The well is much smaller in diam-
eter than a mine shaft, and only one well is
required instead  of the two  or  three  shafts
that would be necessary in a conventional
mine.   Therefore, avenues for connection of
groundwater  with  the well (and repository)
are more easily and reliably avoided.
                                            209

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Subsurface Disposal Of Waste

     Waste disposal  in  salt mines  has  been
performed at two locations in West Germany.
They are the Asse salt mine, which was used
for  radioactive  waste  disposal  for  many
years,  and  the Untertage-Deponie  (subsur-
face repository) Herfa-Neurode,  which has
been in successful operation for disposing of
chemical waste since 1970.(3).

     Although  waste disposal in leached cav-
erns has  only  been investigated  using  pilot
plants, there are several reasons why this al-
ternative is becoming more and more attrac-
tive.  The basic idea is to process the waste
on the surface in such a way that it can be
transported through  the  wellbore  into the
cavern  where  it  settles  until the  storage
space is  totally filled.  In  the final step, the
well will be plugged, thus preventing any fur-
ther contact between the waste and the envi-
ronment.  No further operations  or  controls
are necessary.

     There are several  advantages  to using
solution  mined caverns instead of  conven-
tional  mines for hazardous waste disposal.
First, no personnel  or equipment are  required
underground except for the steel  tubing that
provides access to the cavern. Secondly, ac-
cess to the  waste through the single bore and
tubing  is very  limited, and  therefore safer,
than the multiple and larger shafts  required
for a mine.  Additionally, the construction
cost is much less for a solution mined cavern.

     The "wet" and the  "dry"   deposition
methods are two basic  ways of operating a
waste  cavern.   In  wet  deposition, waste is
transferred directly into the brine, which is
still in the cavern from the leaching process.
By  injecting waste,  the brine will be  dis-
placed to the  surface and then  withdrawn.
This method is simple, but the risk of pollu-
ting the brine  because of the  contact  with
the waste makes this process an undesirable
one. The alternative solution, dry deposition,
requires  the withdrawal of brine prior to dis-
posal of  waste, a process which has been pro-
ven in practice.
     There are two basic types of operations
for transferring waste into the cavern.  The
batch  method,  where  individual cannisters
are lowered into the cavern via a wireline, is
very  time consuming  and labor  intensive.
The  preferred type of operation is the  con-
tinuous method  where  the  waste  can be
pumped or dropped continuously into the well
(Figure 4).
Figure 4.  Concept of Continuous Waste
       Disposal into a Cavern
     When using the continuous method, two
different  approaches  are available  at  pre-
sent.    Both  involve  solidification  of  the
waste.   The first  requires solidification  of
the waste into  pelletized form  on the sur-
face,  or pelletizing waste which is delivered
as solids, followed by dropping the pellets
down  the  tubing into the cavern.  This results
in a tightly packed pile of pellets, although
there will remain a certain amount  of open
pore space between pellets.  The second ap-
proach involves  mixing the waste with a sol-
idification agent and while the mixture is in
                                            210

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slurry form, pumping it into the cavern.  The
slurry composition can be designed to control
the time of solidification in such a way that
a massive, continuously growing block will be
created in the cavern.   In either case,  the
material will  not flow directly  through  the
cemented  casing.    It  will,  instead, flow
through a hanging string of tubing (inside the
cemented casing) because this string  can be
replaced if any problems such as  plugging oc-
cur.

     Theoretical investigations have demon-
strated  that deposition of liquid  waste with-
out solidification appears to be  possible.^)
However,  there are several reasons why solid
or solidified  waste is preferred.   First,  the
mechanical  properties of  solid  waste  are
more favorable than liquid waste. This is be-
cause the mobility of solids  is much lower,
thus eliminating  the  possibility  of   waste
"squeezing" out through leaks. Solidification
also immobilizes the hazardous components,
which minimizes the possibility of reactions
between the  different chemicals.  Addition-
ally, surface  area of the waste is minimized,
which reduces the amount of toxic constitu-
ents that could possibly come in contact with
the environment.

     With the increasing needs for safe han-
dling of radioactive  and chemical  wastes,
solidification technology is being  developed
and refined.  There are several types of  sol-
idification processes  which  may  be   consi-
dered  in  the  case  of  hazardous  or toxic
chemical waste.(5)   Two of the more preva-
lent processes are:

1.   Cement  Based  Processes.   These  use
     well-known technology and inexpensive
     and plentiful raw materials and are  tol-
     erant  to  most   chemical   variations.
     However, relatively large  amounts of
     cement are required which reduces the
     net waste volume.

2.   Pozzolanic  Processes.    These require
     using lime or lime substitutes and poz-
     zolana to produce  a solidified product.
     A  typical pozzolana is flyash.  Materi-
     als are often very low in cost and wide-
     ly available, with  little special equip-
     ment needed  and relatively  well-know
     reactions.
     Each of these processes have inherent
advantages  and disadvantages.  Decisions as
to use will have to be based on the chemical
and physical properties of the specific waste.

Repository Closure

     After the final lift or course of hazard-
ous residual material has  been placed  and
taken its initial set, a cap of structural qual-
ity concrete is placed.   The concrete  cap
completely  fills the void between the solidi-
fied material and the arched roof of the cav-
ern but does not extend  up  into the throat of
the uncased borehole.  The  uncased borehole,
extending up from the throat of the cavern
to the casing shot, is packed with  a  mixture
of sodium chloride, potassium chloride  and
calcium sulphate salts, lubricated by a satu-
rated brine solution.   The lithostatic pres-
sure,  generated by the salt rock, will cause
recrystallization of these  salts, forming  a
solid plug.  This plug, which defies identifica-
tion other than by chemical analysis, effec-
tively seals off the cavern and its contents.
The cased borehole above the recrystallized
plug is cemented back to the surface by con-
ventional  well abandonment procedures.  The
benefit of this closure  technique  is  to  ac-
hieve  the Macroencapsulation of the solidi-
fied hazardous residuals with native materi-
als thus  avoiding  the  possible  failure of
manmade, engineered components.

Post Closure Monitoring

     The  long  term efficiency  of  the  con-
tainment  and isolation system will be moni-
tored over a minimum period of 30 years af-
ter closure.  During the  site characterization
process, performed  during the  permitting
process, environmental  data is accumulated
and assembled into an  environmental back-
ground  model.   Water  samples from peri-
pheral monitoring  wells will be analyzed to
detect chemical changes in the groundwater.
The absence of change in the profile  vali-
dates the integrity  of the repository.
                                           211

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     During placement of the hazardous re-
siduals, minute quantities of  tracer isotopes
are added to imprint the specific hazardous
residuals with a unique signature.  If,  during
the monitoring process, there is a shift away
from the baseline profile, and the trace sig-
nature is  absent,  the change must be attri-
buted  to causes  other  than migration from
the repository.
PROBLEMS ENCOUNTERED

Technical Design

     As  described, the technologies for the
individual components of a hazardous waste
repository in salt exist.  However, the appli-
cation and combination of these elements to
the needs of a hazardous waste  repository
will require some additional research and de-
velopment.  This is true, in particular, in the
selection of the most suitable waste materi-
als, the  solidification process and the slurry
transport.

Regulatory Regime

     RCRA mandates implementation of its
regulations by the Environmental Protection
Agency (EPA).  The Act is not passive, it es-
tablishes technical goals for  the Agency, re-
quires  rule  making and the  development of
enforcement procedures within very specific
and inflexible time  tables.  The regulatory
and administrative burden on EPA is substan-
tial.  The impact on the regulated community
is devistating.  For example, section  3004(b)
of RCRA prohibits the  placement of hazard-
ous waste in salt formations until the Admin-
istrator  (EPA)  promulgates  specific  rules.
The  EPA suggests  that under  its mandated
rulemaking schedule it may  take as long as
42 months before these rules are published.
Can we really wait that long before address-
ing the ultimate containment issue?
Public Education

     The public is aroused about the dangers
of  health  threatening  leachate  migrating
from surface impoundments and landfills into
aquifers  designated  as underground sources
of drinking water.  This  well founded fear is
based upon the common  knowledge that wa-
ter can  migrate  or percolate through soil.
Intuitively, the concept  of water  movement
through underground formations leads to the
erroneous conclusion that salt formations can
be attacked by water  and that  the salt will
be "dissolved away".

     A public education  program designed to
help the  people living  in the proximity of a
proposed containment  repository appreciate
the integrity of a salt dome that has with-
stood the ravages of  200 million years  of
evolutionary geology without being "dissolved
away"  is a self evident need  that must  be
met.

     Everyone is  in favor of cleaning up ex-
isting  leaking surface  impoundments and
landfills.  Everyone is  in favor of  construct-
ing effective  hazardous  waste  management
facilities; - but "NIMBY",  which  translates
into "not in my back yard".  The NIMBY syn-
drome is so  deeply  rooted that even state
governments  have enacted  legislation out-
lawing the construction  of  hazardous  waste
treatment and disposal facilities within their
state.

     Clearly  the  most  significant problem
faced  by those  involved  in the effective
management  of hazardous waste is the pre-
sentation of accurate and timely information
to the public in  an  understandable and be-
lievable manner.  Public  trust can  only come
from an  informed citizenry  and neither the
regulators or the regulated community have
been effective in this critical area.
                                        Disclaimer

    The work*described in this paper was not funded by the U.S. Environmental
    Protection Agency.  The contents do not necessarily reflect the views of the
    Agency and no  official endorsement should be  inferred.
                                           212

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RESULTS

General Experience

     For over  30 years, solution mined cav-
erns in salt  formations have been used  for
storage of  hydrocarbon  liquids and  gases.
They  have been located in both bedded and
domai  salt deposits  and operated by oil and
gas companies, pipeline companies and vari-
ous   other   energy-related  organizations.
Since  1978,  the  Department  of  Energy's
(DOE)  SPR  Program has been  creating and
filling  salt caverns with crude oil to maintain
a reserve  in case of national emergency.  At
the time of this writing, more than 380 mil-
lion barrels of crude oil are in storage in sol-
ution mined caverns created in salt domes in
Louisiana  and Texas.   All of this crude oil,
considered a hazardous liquid if spilled, is be-
ing safely contained under pressure without
threatening the environment.

     In 1965, the Atomic Energy Commission
(AEC),  with  the assistance  of Oak  Ridge
Laboratories,  deposited high level nuclear
fuel  rods  in  the  Carey salt mine in  Lyons,
Kansas.  The principal  objective of this ex-
periment,  called  project Salt Vault, was  to
demonstrate  both the feasibility and  safety
of the disposal of solidified high-level raio-
active  wastes in salt cavities. This included
demonstration  of techniques  and equipment
which might be used in  an actual disposal  fa-
cility as well as the  collection of data on the
properties and behavior of in-situ salt sub-
jected to this radioactive material. The pro-
ject was a success in all of these areas during
its two years of operation.

     At present, the Waste  Isolation Pilot
Plant  (WIPP)  is  under  construction near
Carlsbad,  New Mexico.  It is a  research and
development  facility to demonstrate the safe
disposal in salt of  radioactive  wastes from
the United States defense prograrns.(6) Mine
shafts  have been sunk  and enlarged;  exten-
sive excavation of rooms in the  salt has been
completed  and detailed data gathering and
testing  has been  accomplished.  The next
step is an actual test of nuclear waste dispo-
sal on  a small scale in  the salt.  Barring un-
forseen complications or problems, the WIPP
could be ready for  receipt of radwaste on a
full-scale basis within two or three years.
     In West Germany, the Asse II salt mine
was acquired by the government-owned com-
pany  GSF (Gesellschaft  fuer Strahlen und
Umweltforschung) in 1965 for the purpose of
conducting research and development work
for the disposal of radioactive waste in salt.
From  1968 to  1978, 125,000 barrels of low
level  and 1,200 barrels of medium level  ra-
dioactive waste were disposed in this  mine.
The  experience gained from this full-scale
plant is one of the  bases for the design and
future operation of the official West German
radioactive waste disposal facility at Gorle-
ben, which is now under construction.

     Three   investigative   programs  per-
formed in the Asse  II mine are of particular
importance  for the  design  of  a hazardous
waste  disposal facility  in  salt  caverns,  as
they are directly applicable.

L    To investigate the rock mechanical sta-
     bility and the volume closure of a deep
     cavern  under atmospheric  pressure, a
     63,000 bbl cavern was mined and inten-
     sively investigated over a  period of 7
     years.   It was demonstrated that even
     at the depth of 3200', no stability pro-
     blems  occurred.  The  percent  volume
     losses due to creep stabilized at 0.4%
     per year.(7)

2.    Kavernen Bau-und Betriebsgesellschaft
     mbH,  German  parent  company   of
     PB-KBB Inc., leached 5 model caverns
     within the  mine.   These  excavations
     were filled  with a representative mix-
     ture of  cement slurry and dummy pel-
     lets.  During this experiment the hydra-
     tion temperature in  the  settling ce-
     rnent,  the spreading behavior and the
     mechanical properties of the solid mass
     were investigated intensively. (8)

3.    At the  present time, a demonstration
     plant for testing long distance  slurry
     pumping is under operation.  A pipeline
     was  installed from  the surface to the
     3150' level.   A total of 6300 bbl of ce-
     ment slurry  is  to be  pumped  into the
     mine at a design flow rate of 30 bph.
     The  aim  is  to  investigate long-term
     safe pump operation and the mechani-
     cal quality of the solidified cement.
                                           213

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     In regard to operating a chemical waste
disposal  facility in salt, there is  one known
subsurface  repository at  Herfa-Neurode  in
West Germany.  This full-scale plant in an
abandoned potassium  mine is  commercially
operated by the firm Kali+Salz.  Since 1970,
when this mine was converted to a hazardous
waste  repository, more than 400,000 tons of
waste  have been dumped at a depth of about
2300'.  The waste is delivered  to  the site by
truck  in barrels on one-way  pallets.  Each
kind of waste must first be accepted by the
operator and the supervising authority. Liq-
uid waste will be stored only after solidifica-
tion.

     In the comprehensive article in Nation-
al Geographic "Storing Up Trouble...Hazard-
ous Waste", this plant was mentioned as the
most impressive solution  to  the hazardous
waste disposal problem.(9)
CONCLUSION

The elements of a  balanced four  part  pro-
gram to eliminate the hazardous waste  pro-
blem are:

1.   Elimination of,  or the  reduction  in
     quantity of, the hazardous wastes  gen-
     erated;

2.   Rendering of the unavoidably generated
     hazardous wastes  nonhazardous by ap-
     propriate treatment technologies;

3.   Disposal of the treated,  nonhazardous
     constituents in regulated landfill facil-
     ities;

4.   Ultimate containment and isolation  of
     the indestructible  and  untreatable so-
     lidified hazardous residual constituents
     in repositories  constructed in geologic-
     ally stable salt  formations.

     The required technological tools are  at
hand, the legislative intent has been enacted
and the regulatory mechanism is being devel-
oped.   Significant progress  in the manage-
ment of hazardous waste is imminent.
REFERENCES
     National  Fire  Codes,  1981, National
     Fire  Protection  Association, Vol.  14,
     pp. 72, 232 and 381.

     Funderburk,  Ray,  1985, "Disposal  in
     Salt;  The Fifth Alternative".  PB-KBB
     Inc.  Paper,   Pollution   Engineering
     Magazine, 3uly 1984.

     Finkenwirth, A.: Oohnsson, G., "Die Un-
     tertage -  Deponie Herfa-Neurode  bei
     Heringen/Werra" (The Subsurface Repo-
     sitory Herfa-Neurode  near Heringen/
     Werra).  Paper presented at  the 5th Salt
     Symposium in Hamburg, West Germany.

     Wallner,   M.;  Langer,  M.;  Wassmann,
     Th.:  "Gebirgsmechanische  Bearbeitung
     von Stabilitaetsfragen fuer Deponiekav-
     ernen im  Salzgebirge (Rock Mechanical
     Investigations for Disposal  Caverns  in
     Salt Rock)".  Kali+Stelnsalz, 2/1984, p.
     66-76.

     "Guide to Solidification Technology and
     Services",  The Hazardous Waste  Con-
     sultant; Nov/Dec  1983.

     Miller,  3.D.,  Stone,  C.M., and  L.3.
     Bransetter,  1982,  "Reference Calcula-
     tions  for  Underground Rooms  of the
     WIPP".  Report No. SAND82-1186, San-
     dia National Laboratories, Albuquerque,
     NM, 121 p.
5.
6.
7.
8.
9.
     Lux,.
     wurf
U.H., "Get
una 'Feldei
               biresmechanis.cher Ent-
              erianrung in balzkaver-
nenbau", 1983  Enke  Verlag, Stuttgart
(West Germany).
     Quast, P., Schmidt, M.W., "Disposal of
     MLW/LLW in Leached Caverns".  Paper
     presented at  the 6th Salt Symposium in
     Toronto, Canada, May 1983.

     Borkaido, A.A., "Storing Up Trouble...
     Hazardous  Waste".  National  Geogra-
     phies 3/85, p.319-351.
                                           214

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                    LABORATORY AND PILOT PLANT ASSESSMENT Of  THE
                ACID PRODUCTION POTENTIAL OF MINING WASTE MATERIALS

                           A.  Bruynesteyn and Associates
                            Mineral  Leaching Consultants
                               2175 Greylynn Crescent
                               North Vancouver,  B.C.
                                  Canada  V7J 2X6
                                      ABSTRACT

      The role of the microorganism Thiobaci11 us  ferrooxidans  in  the  oxida-
  tion of sulphide minerals  and the production of acidic  effluents  from
  mining wastes is discussed and the chemistry involved explained.  T\_
  ferrooxldans plays  an  important role in  acid production  due  to  its  ability
  to rapidly oxidize  reduced sulphur and iron  which,  when  sulphides are
  present, and result in the generation  of sulphuric  acid.   The sulphide
  mineral pyrite (FeSg), often present in  mine waste  materials, is  generally
  recognized as the chief source of acid mine  drainage.

      A small-scale test procedure is  explained which rapidly  evaluates the
  inherent capability of a waste material  to produce  an acidic effluent.   If
  the waste material  is  assessed as a  potential acid  producer, then scale-up
  testing procedures  are available which can be used  to simulate  the  charac-
  teristics of the effluents produced  from a commercial sized  waste dump.

      During periods  of  little rainfall, localized  biological  activity may
  occur in wet areas  of  a dump, resulting  in the  possible  accumulation of
  water soluble pollutants.   The length  of these  dry  periods greatly  affects
  effluent loadings and  characteristics  during subsequent  rainfalls.

      Acid-base accounting can be used to  identify  where the acid producing
  and acid consuming  materials are located in  an  orebody.  The data produced
  from tests on core  samples,  composited over  suitable short intervals from
  multiple drill  rioles,  can  provide an excellent  overview  of the  distribution
  and placement of both  aklaline and sulphidic  materials.
                                  Di sclaimer

The work described in this paper was not funded by the U.S.  Environmental
Protection Agency,  The contents do not necessarily reflect the views of the
Agency and no official endorsement should be inferred.
                                    215

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 AN OVERVIEW OF PILOT-SCALE RESEARCH IN HAZARDOUS WASTE THERMAL  DESTRUCTION
                Chun Cheng Lee, Ph.D. and George L.  Huffman
                    U.S. Environmental  Protection Agency
                              Cincinnati, Ohio
                                  ABSTRACT

     The enactment of the Resource Conservation and Recovery Act  (RCRA)  of
1976, Toxic Substances Control Act (TSCA) of 1976 and Superfund legislation
of 1980 has intensified research in the area of hazardous waste thermal
destruction.  As a result, a large amount of useful information has  been
accumulated.  This paper summarizes and compares ongoing pilot-scale
studies being conducted in this area ranging from oxidation to  pyrolytic
thermal destruction, and from conventional to innovative processes.   This
paper provides:

 - Information summarizing the thermal  destruction testing results  for
   selected waste compounds.

 - Recommendations regarding future directions in the area of hazardous/
   toxic waste thermal destruction research.
INTRODUCTION

     Unsound disposal  of organic haz-
ardous/toxic wastes has been posing
a serious threat to human health
and the environment.  The Federal
government responded to the criti-
cal hazardous waste problem with
the enactment of the Resource Con-
servation and Recovery Act (RCRA)
in 1976 (Public Law 94-580), Toxic
Substance Control Act (TSCA) in 1976
(Public Law 94-469), and a comprehen-
sive "Superfund" program in 1980
(Public Law 96-510) to assure the
reliable management of hazardous/
toxic waste disposal operations
and dump site clean-up.  The enact-
ment of these Laws has intensified
research into the thermal  destruction
of organic chemical  waste and the
research has accumulated a large amount
of useful information.  This paper
describes some of the past and current
efforts in the area of pilot-
scale research that has come about
due to the passage of RCRA and TSCA.
The purpose of this paper is to pro-
vide information relative to "who is
doing what" for the hazardous waste
management industry in terms of gener-
ating research information and rela-
tive to planning future programs.
This paper covers the following
research activities:
                                    216

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1.  EPA's Combustion Research Facil-
    ity (CRF) at Pine Bluff, Arkansas

2.  EPA's Destruction of Hazardous
    Wastes Cofired in Industrial
    Boilers

3.  EPA's Mobile Incinerator at Edi-
    son, New Jersey

4.  EPA's Controlled Temperature
    Tower at Cincinnati, Ohio

5.  EPA's Rotary Kiln Incinerator
    Simulation at Research Triangle
    Park, N.C.

6.  Fundamental  Flame Combustion
    Research Program at Union Carbide

7.  EPA's/New York State's Destruc-
    tion of Hazardous Waste Using
    Plasma Arc Technology

8.  Destruction of Hazardous Waste
    Using Huber's Advanced Electric
    Reactor

PILOT-SCALE RESEARCH OF HAZARDOUS
WASTE THERMAL DESTRUCTION

1.   EPA's Combustion Research Facil-
     ity (CRF) at Pine Bluff, Arkan-
     sas4

Research Scope

 -  To develop methods of improving
    the reliability and controllabili-
    ty of the incineration processes.

 -  To understand the hazardous waste
    incineration processes and to
    assist in the development of
    methods to predict the perfor-
    mance of incinerators.

 -  To support RCRA incinerator regu-
    lations and performance standards,
    and to provide additional  techni-
    cal basis for those future stand-
   ards which may be necessary.

Research Approach

     The CRF, located at the site
of the National Center for Toxico-
logical Research, Pine Bluff,
Arkansas, houses a rotary kiln (con-
struction completed in July 1984)
and a liquid injection incinerator
(currently under construction).
Major characteristics of the rotary
kiln include:

-  A rotary kiln incinerator (8*
   length x 4'  diameter, 1.8MMBtu/hr)
   and an afterburner (10*  length
   x 3' diameter, 1.8MMBtu/hr).

-  Primary fuel for both the kiln
   and afterburner is propane.

-  Scrubber and air pollution con-
   trol devices (3800 ACFM capacity).

-  Sampling systems and analytical
   instruments  are comprised of
   two gas chromatographs (GCs) with
   Autosamplers, a high pressure
   liquid chromatograph (HPLC), and
   associated sample preparation
   equipment.  Hot-zone sampling  is
   available in both the kiln and
   the afterburner transfer ducts
   to complement sampling of stack
   gases.  Real-time monitoring of
   02, CO and C02 levels is provided
   by an automated system.   EPA
   Method 5, Modified Method 5 (using
   cooled XAD-2 resin collection
   medium), and the volatile organic
   sampling train (VOST) system for
   relatively low-boiling organics
   are routinely used.

   Research Status

        Hexachlorobenzene (HCB) and
   1,2, 4-trichlorobenzene  (1,2,4-TCB)
   have been used as surrogate Prin-
   cipal  Organic Hazardous  Constitu-
                                    217

-------
ents (POHCs) to test the perform-
ace of the rotary kiln during 34
test burns.  These two compounds
were tested as POHCs because
they are recognized as thermally
stable compounds, widely found in
certain categories of industrial
hazardous wastes, and suspected of
being precursors in the formation
at elevated temperatures of poten-
tial ly significant products of
incomplete combustion (PICs).

Testing

     Measurement results are com-
pared to combustion stoichiometry
which can be depicted as follows:

  (A)  Propane Combustion;
       CaHs + 502—»»3CQ2 + 4H20
  (B)  Toluene Combustion:
       CjtiQ + 902—»7CQ2 + 4H2Q
  (C)  TCB Combustion:
       CeHsCls + 602-*6C02 + 3HC1
  (D)  HCB Combustion:
       CCl
Findings and conclusions of the 34
test burns are summarized below:

 -  The CRF rotary kiln system can
    consistently produce Destruc-
    tion and Removal Efficiency
    (ORE) values above 99.99% for
    refractory POHCs {HCB and
    1,2,4-TCB).

 -  ORE values below 99.99f were
    obtained during several types
    of failure mode simulations
    (flameout in kiln or after-
    burner).

 -  The feed of HCB or  1,2,4-TCB in
    toluene produced a large number
    of PICs, notably polyaromatic
hydrocarbons (PAH) and other
chlorinated benzenes.  The PICs
were tentatively identified by
GC methods and confirmed by
GC/MS.  A number of these com-
pounds are toxic or possibly car-
cinogenic.  No dioxins or diben-
zofurans were identified in any
of the analyses for PICs,  Exam-
ples of PICs at the ppm to ppb
concentration level identified
from the HCB and 1,2,4-TCB burns
are:
   1,3-dichlorobenzene
   1,2,4-trichlorobenzene
   hexachloroethane
   1,2,4,5-tetrachlorobenzene
   benzyl chloride
   pentachlorobenzene
   hexachloro-1,3-butadiene
   hexachlorobenzene
After a test burn with either HCB
or 1,2,4-TCB in the feed, signifi-
cant amounts of the POHC were
found to be emitted during subse-
quent tests wherein the only feed
to the kiln was propane fuel.

Analytical  data from hot zone
samples show that the concentra-
tions of organic compounds found
did not correlate with parti cu-
late levels, which supports the
assertion that the organic mole-
cules are in the vapor state (not
strongly associated with particu-
lates) in the hot zones.

Deliberate reduction of excess
air levels resulted in signifi-
cant production of soot and PICs
but did not produce higher levels
of CO in the combustion gases.

Complex chemical interactions
occur in the afterburner.  In the
case of HCB as the POHC, for exam-
ple, previously formed intermedi-
ate combustion products may react
                                     218

-------
    to form additional HCB in the
    afterburner.  Under some condi-
    tions, POHC output from the
    afterburner was greater than the
    POHC input to the afterburner.
    This could result from reactions
    between intermediate products,
    hold-up from previous burns, or
    a combination of these effects.

    There was no apparent effect of
    residence time/temperature or
    feed rate on ORE over the ranges
    covered in the test series.

    ORE values for 1,2,4-TCB were
    higher than for HCB under compar-
    able residence time/temperature
    conditions.

    Most of the thermal destruction
    occurred in the kiln.

    There is apparently a direct
    relationship between the DE (Des-
    truction Efficiency) of the
    afterburner (DE/\B) and the POHC
    injection rate at very low injec-
    tion rates.  The behavior of the
    DE^B at very low injection rates
    appears to result from a combina-
    tion of POHC/ PIC carry-over
    (holdup) from previous burns
    plus PIC formation in the after-
    burner.

2.  EPA' s Destruction of H aza rdous
    Wastes Cofired in Industrial
    Boilers^'~

Research Scope

    To gather data to aid the EPA in
    selecting a strategy or set of
    strategies for regulating the
    combustion of hazardous wastes
    in boilers.

    To identify which of several
    boiler operating parameters have
    a major impact on boiler destruc-
   tion and removal efficiency.

-  To evaluate and, if practical,
   establish a mathematical model
   for predicting an upper limit on
   the amount of cofired waste that
   could be charged.  In particular,
   those parameters that could be
   easily changed by an operator or
   might represent major differences
   between boiler types were studied,

-  To gain sufficient information to
   allow judgments regarding what
   particular parameters are useful
   in comparing pilot-scale with
   full-scale boilers.

-  To obtain information that would
   give insight on how regulations
   might be cast so that trial  burns
   would not be needed.

Research Approach

-  Under a contract to EPA, the
   Acurex Corporation conducted this
   study and carried out testing at
   Acurex's site in Mountain View,
   California.

-  The pilot-scale furnace tested
   was a packaged D-type water
   boiler and had a rated capacity
   of about 1.5 million (MM) Btu/hr.

-  A detailed characterization of
   the thermal history and environ-
   ment of the furnace under various
   sets of operating conditions was
   carried out.

-  A study of the ORE of one com-
   pound as conditions were varied
   was conducted.

-  A study of the DRE's of several
   compounds burned simultaneously
   (a composite "soup") was per-
   formed.
                                     219

-------
  -   Parameters  studied  Included
     excess  air  rate,  fuel  firing  rate,
     amount  of water-wall surface area,
     swirl setting and waste type.

 -  Chlorobenzene was  used  for the
   single compound.   For the multiple
   compound tests, chlorobenzene was
   fired with carbon  tetrachloride,
   chloroform,  methylene chloride,
   and dichloroethane.

 Testing

     All tests  were performed in the
 Acurex Pilot-Scale Furnace.  The fur-
 nace has a  single burner,  front wall
 fired, into a horizontally oriented
 firebox.  The premixed fuel oil/waste
 mixture is pumped out of drums
 through a pressure-atomizing nozzle
 and  stabilized  at the front wall.
 The  fuel flow is monitored by rota-
 meter.  Combustion air is  preheated
 and  injected in the annular region
 around the fuel delivery tube.  The
 International Flame Research Founda-
 tion (IFRF)/ Acurex burner design
 allows swirl adjustment by rotating
 swirl blocks.  Air flow is monitored
 by hot wire anemometer.

     In general, a test is divided
 into four stages:  fuel preparation,
 furnace heatup, sampling,  and analy-
 sis.  Fuel was  prepared by mixing
 known volumes of waste and distillate
 oil  in clean 55-gal  drums.  Furnace
 heatup could occur either  from a
 cold start or a hot start, and invol-
 ved  bringing the furnace walls to a
 preset temperature (below  the expect-
 ed run temperature) with natural  gas
 firing and then switching  to the test
 fuel until  the temperature reached
the  final  run temperature.  This
 heating phase could take from 4 to
 16 hr.   Sampling was done  for the
temperature readings and gas sample
 locations specified for the program.
Analysis encompassed both  the prerun
preparation and QC of sampling trains
and collected media as well as post-
run analysis of the collected samples.

     Test series A, the baseline stud-
dies, consisted of seven runs, all
with no waterwalls present.  Three
swirl settings, two nominal firing
rates, and three nominal stoichio-
metries were considered.  Baseline
conditions (no waste in the fuel) were
were not repeated with waterwalls be-
cause it was found to be unnecessary.
Thus work could immediately start on
ORE studies.  Test series B, the
single compound tests consisted of ten
runs, seven without waterwalls and
three with waterwalls.  Two nominal
firing rates, three stoichiometries,
and two swirl settings were studied.
Test series C, the multiple compound
tests, included 32 runs, all with
waterwalls present in the firebox.

Study Conclusion

     Of the variables studied, the
order of influence on ORE is: water-
walls > compound * excess air >
firing rate » flame shape.   The order
of influence on temperature profiles
is:  waterwall > excess air > firing
rate > compound ts> flame shape.
Except for waste composition, the in-
fluence of operational variables on
ORE corresponds to the influence of
temperature.  From comparison of ORE
with and without waterwalls it is
concluded that in-flame destruction
accounts for only about 90  to 99
percent of the ORE.  The remaining
destruction must be achieved from
postflame thermal oxidation and de-
composition.

     Residence time within  flame is
insufficient to destroy both POHC's
and PIC's.  Without sufficient post-
flame time and temperature, the quan-
tity of PIC's passing out of the boil-
ler will  be significant.
                                     220

-------
     Significant VOC (Volatile Or-
ganic Compound) PIC's emitted during
combustion of chlorinated organics
include methylene chloride, ethylene
trichloride, perchloroethylene, and
the ethylene dichlorides.  Suspected
VOC PIC's but not positively identi-
fied include chloromethane, chloro-
ethane, chloroethylene, and propylene
chloride.  The testing also showed
that although DRE's for both POHC's
(chlorobenzene and carbon tetrachlor-
ide) are greater than 99.99 percent,
the ORE of total chlorinated organics
as fired is only 99.985 percent.

     A model capable of predicting
within a few degrees the temperature
profile within a furnace has been
validated.  The model can be used to
predict within an order of magnitude
the destruction efficiency of the
modeled furnace.
  3.   EPA's  Mobile Incinerator at
       Edison. New Jersey0'^

  Research Scope

     - To provide a mobile facility for
  on-site thermal destruction/detoxifi-
  cation of hazardous and toxic organic
  substances.

  Research Approach

       In 1981, EPA constructed a mobile
  incinerator system which consists of
  four heavy duty, over-the-road, semi-
             They are:
trailers.
-  Trailer
-  Trailer
  -  Trailer 3:
  -  Trailer 4:
 Trial  Burns

     The  key  test materials  and purposes are as fol
                         TRIAL BURN TEST SUMMARY
Rotary kiln
Secondary combustion
chamber
Scrubber and air
pollution controls
(APC)
Combustion and stack
gas monitoring equip-
ment
               lows:
Test
No.
1
2
3
Feed
Material
Diesel Fuel
1.2% Fe203c
98.8% Diesel fuel
21.4% CCl4d
Number
of Runs
2 ORE*
2 Particulateb
3 Particulate
3 ORE
Test Purpose
Baseline performance
Particulate removal
efficiency of APC.
Destruction of RCRA
       28.9% e6H4Clo
       49.7% Diesel fuel
       11.4% Askarelf
       88.6% Diesel fuel

       39.3% Askarelf
       60.7% Diesel fuel
3 Particulate

3 ORE
3 Particulate

3 ORE
3 Particulate
                organic; HC1  removal
                efficiency of APC.
                Destruction of PCB
                (TSCA); HC1 removal
                efficiency of APC.
                Destruction of PCB;
                HC1 removal
                efficiency	
 a  -  Destruction  and  removal efficiency of principal orgamcs.
 b  -  NJDEP  Incineration Test Method
 c  -  Iron  oxide.
 d  -  Carbon tetrachloride  or tetrachloromethane
 e  -  Ortho-dichlorobenzene or  1,2-dichlorobenzene
 f  -  58.9%  Aroclor  1260, 35.0%  trichlorobenzenes, 6.1% tetrachlorobenzenes
                                     221

-------
Trial Burn Results

     The test results from the trial
burn cover principal performance
criteria:  (1) particulate matter
removal efficiency, (2) HC1 removal
efficiency, (3) organic destruction
and removal efficiency, (4) waste-
water quality, and (5) ambient air
quality.  The first three criteria
are related to stack emissions and
are heavily regulated by the RCRA.
The requirements specified by RCRA
are:  (1) maximum allowable particu-
late matter emission rate of 180
mg/Jti3 when corrected to 7% oxygen
in the stack gas; (2) HC1  removal of
99% or a release of 1.8 kg/hr (4
Ib/hr) for the stack emission,
whichever is greater; and (3) mini-
mum organic ORE (e.g., for tetra-
chl oromethane, trichlorobenzenes,
and tetrachlorobenzenes) of 99.99%.
During all trial burn tests, the
system performance met the require-
ments for each of these criteria.

The POHCs and their DRE's  found
during the trial burns were:

      POHC          ORE
      'CCTJ          >99.99996
      C6H4C12       >99.99998
      CgHsCls       >99.9998
      C6H2Cl4       >99.9994
      Aroclor 1260  >99,9998

     The water quality criteria
covers the analysis of TQC, pH,
temperature, total dissolved solids,
total  suspended solids, petroleum
hydrocarbons, volatile organics,
and the test organic compounds.
The concentration of the test
organics in the wastewater was
lower than 20 _ug/l (ppb)(i.e.,
limit of detection) during the en-
tire trial burn.  The main contamin-
ants in the wastewater were
dissolved salts from the neutrali-
zation of acid gases (HC1  and
  fuel-oil derived SOg) with scrubbing
  solution (sodium bicarbonate and
  carbonate).

       The ambient air quality criteria
  cover air collection and analysis at
  0.3 to 1.0km downwind from the
  incinerator stack.  No measurable
  quantities of chlorobenzenes or PCBs
  were detected.  The detection level
  for both trichlorobenzene and
  tetrachlorobenzene was 0.1 jig/m3 and
  for PCBs (as Aroclor 1260) was 1.0
  jjg/m3. These data verify the conclu-
  sions of an EPA air dispersion model-
  ing evaluation (conducted prior to
  the trial burn) which indicated that
  the mobile incinerator would not
  adversely impact the quality of air
  in the local  community.

       As a conclusion, based on the
  high combustion and destruction
  efficiencies measured during the trial
  burn, the EPA Mobile Incineration
  System has been shown to be an effect-
  ive implement for the destruction of
  hazardous organic materials.  In fact,
  the level of combustion and destruc-
  tion reported was essentially based
  on analytical limitations of measure-
  ment rather than on the actual finding
  of hazardous components in the stack
  emissions. The results of the trial
  burn indicate that the system appar-
  ently met or exceeded all applicable
  federal requirements for incineration
  systems.

  4.  EPA's Control1ed Temperature Tower
  at Cincinnati, Ohio^

  Research Scope

  -  To establish how combustion parame-
     ters and variables affect failure
     of a simulated hazardous waste
     incinerator or an industrial
     boiler that cofires hazardous
     waste with conventional fuel to
     achieve 99.99% ORE;
222

-------
   To determine how, when and why PICs
   are formed (e.g., too low oxygen
   concentration or too low an operat-
   ing temperature) and to determine
   how or whether they can be subse-
   quently destroyed or removed
   (e.g., by secondary combustion or
   scrubbing/ adsorption techniques);
   and
   degree of back-heating provides
   various thermal profiles in this
   third section.

   The chamber downstream of the flame
   can be used to study the impact on
   ORE and on PIC minimization of the
   use of secondary combustion tech-
   niques.
-  To determine which organic chemi-  ResearchStatus
   cals are the hardest to burn (this
   will assist in making better POHC
   selections).
Research Approach

     To supplement its extramural  re-
search, EPA has constructed both
pilot- and bench-scale combustors  at
their Center Hill Facility, part of
their Hazardous Waste Engineering
Research Laboratory in Cincinnati,
Ohio.  The largest of these combus-
tors known as the Controlled Temper-
ature Tower (CTT) is very flexible
for the simulation of incinerator
behavior at the small pilot scale and
has the following special features in
its reactor chamber:

-  In the flame zone, the chamber is
   refractory-lined.  The main flame
   is typically a swirl-stabilized
   turbulent spray flame.  A variable
   swirl-block IFRF burner is avail-
   able that allows testing nominally
   at 150,000 Btu/hr.

-  The second section is equipped
   with cooling coil access.  Thus,
   the heat extraction rate can be
   varied by changing the amount of
   cooling coil surface exposed
   [ranging from no heat removal to
   very high removal (to provide
   extreme thermal quench rates)].

-  In the third section, the wall  is
   auxiliary-heated to reduce losses
   from the furnace gases.  The
    The unit has been installed and
is undergoing shakedown testing.
Personnel  responsible for operating
this unit are currently fine-tuning
testing protocols, performing QA/QC
activities, and readying the unit for
longer term operation.

5.  EPA's Rotary KiIn Incinerator
    Simulation at Research Triangle
    Park (RTF), N.C.1

Research Scope

-  To determine time/temperature re-
   quirements for solids detoxifica-
   tion

-  To develop process information

-  To predict materials interactions

-  To provide detailed information on
   operational failure modes

Research Approach

     A pilot-scale rotary kiln com-
bining with a vertical afterburner
was recently installed at the EPA-RTP
facility.  The unit has the capacity
of 350..000 Btu/hr with natural gas as
the major fuel and has an after-
burner rated at 160,000 Btu/hr.
The unit was designed to simulate the
function of a full-scale rotary kiln
for evaluating various parameters
such as:
                                     223

-------
A.  Parameters of simulation
 -  Kiln motion and rotation speed
 -  Wall temperature
 -  Gas temperature
 -  Solids time/temperature profile
 -  Transient characteristics (feed-
    ing effects)

B.  Parameters that affect failure
    modes
 -  Overcharging:
    •Aqueous waste
    •Volatile release
 -  Materials Interaction:
    •Capsulation
    •Insulation
 -  Short circuiting
    •Insufficient solid phase
     residence time
 -  Flame perturbations

C.  Parameters that affect solids de-
    toxification
 -  Burning mass thickness and motion
 -  Wai I temperature
 -  Gas temperature
 -  Flow field
 -  Solids residence time
 -  Gas emissivity
 -  Load
 -  Transient characteristics
 -  Gas composition

The general  approach to be used
on this project includes:

A.  Establish and validate simulation
    capability.  Compare with full-
    scale data where available.
    (Temperatures, times, loading).

B.  Conduct screening experiments
    to:
 -  Pose critical questions
 -  Identify critical phenomena
    controlling ORE'S
 -  Establish pertinent hypotheses

C.  Conduct critical experiments to
    prove or disprove hypotheses;
    specific approaches will include:
 -  Proper selection of solid
    waste mixtures such as:
    * Solids and semi-solid
      chemical wastes
    * Contaminated soils
    * Containers:  Scaled-down
      drums containing surrogate
      hazardous wastes

 -  Measure ORE versus:
    * Time
    * Size of charge (waste
      concentration)
    * Performance parameters (THC,
      CO)

 -  Analyze for PIC's; determine
    impact on PIC levels of:
    * Temperature profile
    ' Excess 02

6.  Fundamental Flame Combustion
    Research Program atUnion Carbide^

Research Scope

 -  To develop a better understanding
    of what is going on in the flame
    zone when fuel oils of different
    (chemical  and/or physical) proper-
    ties are burned.

 -  To maximize the hydrocarbon des-
    truction efficiency and minimize
    the production of incomplete
    combustion intermediates.

Research Approach

       A research combustor (liquid in-
 jection) has been constructed and has
 been tied in with the existing Union
 Carbide South Charleston Technical
 Center waste incinerator.  The exist-
 ing Union Carbide South Charleston
 Technical Center waste incinerator
 manufactured by Brule has three com-
 bustion chambers.  The new combustor
 has been tied into the bottom of the
 second existing combustion chamber
 and shares the third existing combus-
                                    224

-------
tion chamber to provide additional
residence time and better mixing.
The two systems have been connected
together with an 18 foot long, re-
fractory-lined, 2 foot ID duct.  A
cut-off blind has been Installed near
the new research combustor so that
the two systems can be separated
completely.  The new research com-
bustor will be operated only when the
existing waste incinerator is not
being used so that the new research
combustor will have no impact on the
operation of the existing incinerator
(and vice versa).

     The research combustor was de-
signed for a normal load of three
million Btu/hour and a three second
residence time.  (An additional one
second residence time is provided
by the 18 foot refractory-lined duct
and the up-pass combustion chamber
of the existing incinerator.)  The
maximum load is five million Btu/hr.
The normal  design operating tempera-
ture is 2200°F and the maximum
operating temperature is 2500°F.

     The system was designed to be
able to test different burners,
different nozzles and different pro-
perty fuels.  In the initial  stage, a
research burner developed by the In-
ternational Flame Research Foundation
will be used extensively to study the
impact of various air/fuel mixing
patterns on the flame zone.  Other
burners may be studied at a later
time.  For the first year, only fuel
oils (Nos. 2 through 6) will  be
burned in the research combustor.  No
actual hazardous wastes under 40 CFR
PART 261, Subparts C and D will be
tested.  After gaining experience
with fuel oils, Union Carbide will
start the RCRA Part B application
process so that research on the
combustion of real  hazardous wastes
can begin.
EPA ' s/New Yq rk . St at Lej J3est ru ction.
of~Haz'a rd'qy s '.' Wist e
   1
7.
Research Scope

 -  To test the limitation of the
    plasma technology capability to
    destroy and remove a variety of
    hazardous wastes.

 -  To provide data which is necessary
    to establish conditions of contin-
    uous operation, system durability,
    and costs for maintaining the sys-
    tem.

 -  To encourage the development and
    demonstration of innovative
    technologies for treating and
    destroying hazardous wastes in a
    more cost-effective manner or to
    dispose of the waste which
    conventional techniques cannot
    handle.

 -  To provide a proven method for New
    York State to dispose of difficult-
    to-treat wastes.

Research Approach

     Under a Cooperative Agreement,
the EPA's Hazardous Waste Engineering
Research Laboratory in Cincinnati,
Ohio and the New York State Department
of Environmental Conservation co-
sponsor a project to construct and to
test a pilot-scale plasma arc tech-
nology for hazardous waste destruc-
tion.  A plasma (which produces
temperatures estimated to be as high
as 50,000°C) is an ionized gas flow
resulting from an electrical  discharge.
It uses extremely high-intensity
energy to break the chemical  bonds of
hazardous waste molecules down to the
atomic state, and their recombination
results in simple molecules such as
hydrogen, carbon monoxide, carbon and
hydrochloric acid in the effluent
                                    225

-------
gas.  The off-gases from the plasma   Phase I,  Construction of the
system are  scrubbed to remove hydro-  mobile pilot-scale plasma
chloric acid and are then flared.     arc unit.  The capacity of the
                                      unit is nominally designed to
     The implementation of this       be four kilograms (8.8 pounds) per
project involves the following        minute, and to fit, with ancillary
phases of activities:                 equipment, in a 45-foot trailer.
                                      The unit's capacity is around 1.7 x
111                                     106 Btu/hr.  Construction of this
                                      unit has been completed.
J3hase II.  Testing at Kingston, Canada

           Stage 1: Shakedown (completed)

                    2 kg/minute of ethanol(liquid) was tested for 2 hours.
                    The result was satisfactory.  The ethanol was destroyed
                    to the undetectable level.
                                                              % Compound
           Stage 2: Individual compound tests, 4kg/minute     (by weight)
                     * 3-1 hr. Carbon tetrachloride tests         50
                     * MEK (methyl ethyl ketone) tests            50
           Stage 3: PCB tests, 4kg/minute
                     * 3 - 1 hr. Askarel tests
                     * 3 - 6 hr. Askarel tests
                    Askarel contents:  Aroclor 1242 (thick oil)   10
                                               1254               10
                                               1260               10
                                       Chlorobenzene              20
                                       MEK                        50

           Stage 4: Soup Tests, 4kg/minute

                     "3-1 hr. soup tests
                     * 3 - 6 hr. soup tests

                    Soup contents:  Trichloromethane               5
                                    Tetrachloromethane            25
                                    Trichlorophenol                5
                                    Hexachlorohexane               5
                                    Tetrachloroethene              5
                                    Hexachlorocyclo-
                                     pentadiene                    5
                                    MEK                           50
                                     226

-------
^Phase I II:  Testing of Critical Waste

     If Phase II testing is proven as
successful as is currently anticipa-
ted, the plasma system would be
considered for testing actual waste
in New York State at a hazardous
waste site.

8.  Destruction of Hazardous Haste
    Using Huber's Advanced Electric
    Reactor
Research Scope

 -  To perform tests on both a 3-inch
    (36 pound/hour capacity) and a 12-
    inch diameter (2,500 pound/hour
    capacity, 3.4 million Btu/hr)
    pilot unit constructed by the
    J.M.  Huber Corporation.  The
    purpose of conducting these
    tests is to determine: (1) the
    performance of the AER to des-
    troy PCBs, CC14 and dioxin
    mixed with soils; and (2) the
    suitability of the tested
    solids for landfill under the
    Resource Conservation and
    Recovery Act guidelines.
    The dioxins tested were Octa-
    chlorodibenzo-p-dioxin (OCDD)
    and 2,3,7,8 Tetrachlorodibenzo-
    p-dioxin (TCDD).

Research Approach

     The AER is an electrically-
heated, gravity-fed fluid wall reac-
tor which destroys organics by rapid-
ly heating feed materials to tempera-
tures of 110g°C to 2760°C using in-
tense radiation in the near infrared.
Reactants are isolated from the
cylindrical reactor core by a gaseous
blanket formed by flowing nitrogen
radially inward through the proprie-
tary porous core wall.  Carbon
electrodes, designed to operate reli-
ably at extremely high temperatures,
are located in the annul us between
 the  graphite  core  and  the  outer
 vessel.   These  electrodes  are  used
 to heat  the core wall  to incandes-
 cence.   Heat  transfer  to the feed
 materials is  accomplished  predomin-
 antly  by radiative coupling.   Destruc-
 tion of  organics is  accomplished by
 pyrolysis rather than  oxidation.

     The solid  feed  is gravity fed
 from an  air-tight  feed hopper  into the
 top  of the AER.  Solids fall through
 the  AER  where waste  vaporization and
 pyrolysis occur.  For  a given  reactor
 length,  solids  residence time  is
 determined by the  balance  between the
•highly viscous,  hot  nitrogen and
 gravitational forces.   The product gas
 and  waste solids then  pass through two
 post-reactor  treatment zones (PRTZs).
 The  first PRTZ  is  an insulated vessel
 which  provides  approximately 5 seconds
 of additional gas-phase residence time
 at approximately 1370°C.   The  second
 PRTZ is  water-cooled.   It  primarily
 cools  the gas to less  than 540°C.
 Solids exiting  the second  PRTZ are
 collected in  a  bin which is sealed to
 the  atmosphere  as  a  safety precaution.
 Any  solids remaining in the product
 gas  are  removed by a cyclone followed
 by a baghouse for  fine particle  fil-
 tration. The  product gas then  enters
 an aqueous caustic scrubber for
 chlorine removal.   Any residual
 organics and  chlorine  are  removed  by
 activated carbon beds  just upstream
 of the process  stack.   The product
 gas, essentially nitrogen  at about
 50%  relative  humidity, is  then emitted
 to the atmosphere.

     PCB (Aroclor  1260) was mixed  with
 sand to form a  solid feed  containing
 approximately 3000 jjg/g PCB.   Carbon
 black  was added to the feedstock at
 approximately a 6.25:1 ratio to  the
 PCB  oil  to simulate the organic  carbon
 content of soil.  Carbon  tetrachloride
 was  mixed with  screened,  dried soil
 (less  than 35 mesh) with CC14  concen-
                                     227

-------
 tration  approximately 0.37-13.76%.
 Activated  carbon was added to the
 feedstock  at 94:1  ratio  (w/w) to
 CC14  to  reduce the volatility of
 CC14  and to prevent its  loss before
 reaching the reactor.

      PCB test results reportedly
 show  that, in all  test cases, DREs
 exceeded 99.99999%,  at least an
 order of magnitude greater than the
 requirement of the Toxic Substance
 Control  Act (TSCA)  regulations.
 Maximum  PCB concentrations in the
 treated  feed and baghouse filter
 catch  were 0.001 jjg/g and 0.53
J-ig/g*  respectively.  These values
 are well below the TSCA  limit of 50
)ig/g set for solids  to be
 treated  as hazardous wastes.
Although results for the scrubber
 liquid were variable, ranging from
 0.29 to  2.7 jjg/1,  al 1 were wel 1
 below the  TSCA limit of 50 mg/1 set
 for liquids to be  treated as hazard-
 ous wastes.  The results also re-
 portedly show that PCDDs (dioxins)
 and PCDFs  (furans) at the cyclone
 outlet were below  analytical detec-
tion  limits.

     For the CC14  testing, its ORE
 results  reportedly show values
 greater  than 99.9999%.  These
 results  are at least two orders of
magnitude  better than RCRA require-
ments for hazardous waste inciner-
ators.

     Huber conducted triplicate
tests in Borger, Texas on their 12"
diameter reactors with OCDD (OCDD
mixed with clean soils) in late
October  1984.   Feed concentrations
up to  18000 ppb, by weight, and
feed rates up to 15 pound/minute
were used.  In all  cases, no OCDD
or products of incomplete pyrolysis
 (PIPs) were reportedly detected.

     Triplicate tests of TCDD
contaminated soils were conducted
with the 3" diameter reactor at Times
Beach, Missouri on November 13, 1984.
Again, no dioxin or PIPs were repor-
tedly detected.

Test Conclusion

     The AER has reportedly been
shown to be capable of producing
extremely high operating temperatures
and rapid heating rates resulting in
high destruction efficiencies.
Normal operating temperatures
are in the range of 2200°C to 2760°C
compared to approximately 1650°C for
rotary kiln incinerators.  Although
there is little information in the
literature for reactions at these
temperatures, there is some empirical
evidence that most organic compounds
completely disassociate into their
elemental states.  Data from exten-
sive testing also are reported to
show that intermediate compounds from
partial  reactions of feed materials
are not  formed.  Since these compounds
can add to downstream clean-up re-
quirements, their elimination would
reduce costs for gas cleaning equip-
ment.

     The ability to use very low
gas flow rates provides relatively
long residence times and permits the
use of smaller, less costly, off-the-
shelf downstream gas cleaning equip-
ment.  The destruction capability of
the AER combined with high-efficiency
gas cleaning equipment appears to
allow the achievement of DREs as
close to 100% as a given application
requires.  The ability to use acti-
vated carbon beds also provides
safety back-up for removing hazardous
organics from the process gas if an
equipment malfunction should occur.

     Because it is electrically
heated,  the AER can operate over
a wide range of conditions including:
                                      228

-------
chemical (oxidizing, reduced, or
neutral), temperature (anything up
to 2760°C), and pressure (partial
vacuum to low positive).  Under
reducing conditions, oxygen-con-
taining byproducts such as PCDDs
and PCDFs should not be readily for-
med.  Tests reportedly have verified
this important characteristic.  There
are no significant concentrations  of
products such as organics, C02 and
NOX.  This is an advantage in Air
Quality Control Regions where these
pollutants are a problem.  The
ability to operate under partial
vacuum prevents leakage and greatly
increases the safety of the process.

     The AER has apparently achieved
commercial status by receiving
certification to destroy PCBs on soils
under TSCA.  More extensive permits
under RCRA are currently pending.  The
AER has also reportedly been recommen-
ded for evaluation to detoxify 500,000
tons of dioxin-contaminated soil in
Missouri by the Office of Technology
Assessment.

     For the reasons outlined herein,
Huber believes that the AER technology
has inherent performance, safety and
mobility advantages over comparably-
sized rotary kiln incinerators for
soils detoxification.

CONCLUSIONS AND RECOMMENDATIONS

1.   Table 1 summarizes the re-
search activities reviewed by this
paper.

TABLE
I. SUMMARY OF PILOT-SCALE TESTING FACILITIES
Type of
Facility (Sponsor) Incinerator
1.

2.

3.


4.
5.


6.


7.


8.


CRF (EPA)

Acurex
Facility (EPA)
Mobile
Incinerator
(EPA)
CTT (EPA)
Rotary kiln
Incinerator
Simulation (EPA)
Union Carbide
Facility (Union
Carbide)
Mobile Plasma
Arc Unit (EPA/
New York State)
Advanced Elec-
tric Reactor
(Huber)
Rotary kiln with
afterburner
Boiler

Rotary kiln with
secondary combus-
tion chamber
Liquid injection
Rotary kiln with
afterburner

Liquid injection


Plasma arc reactor


Electric reactor


Process
Oxidation

Oxidation

Oxidation


Oxidation
Oxidation


Oxidation


Pyrolysis
conducted

Pyrolysis
radiation

Capacity (MMBtu/hr)
3.6 (1 ,8 rotary kiln,
1 .8 afterburner)
1.5

15


0.15
0.51 (0.35 rotary
kiln, 0.16
afterburner)
3.0


by 1.7
gas

by 3.4


                                     229

-------
     2.   Table 2 shows what com-
pounds have been tested or are to
be tested by which research insti-
tute.

     3.   Each of the compounds
tested were generally destroyed to
99.99% or greater than 99.99% ORE.

     4.   The products of incom-
plete combustion are probably the
most difficult to research in the
overall area of hazardous waste
thermal destruction.  Almost every
test produces some sort of PICs at
ppm-ppb concentration levels.  The
question is "should ppm, ppb, or
ppt concentrations of PICs concern
the public, the EPA or the technical
community or not?" So far there is
no answer.

     5.   Because PICs could be
more hazardous than the original
compounds, studying PIC formation
and control should be one of the
most important research areas that
EPA and others could focus on.

     6.   Although there is a sig-
nificant amount of experimental
data, no analytical methods have
been developed to predict what DREs
or PICs would result if incinerator
conditions change. Research is
needed to fill that void.
                                    230

-------
                TABLE 2.  COMPOUNDS TESTED OR TO BE TESTED
Compound
Tested By    To Be Tested By
Acetonitrile
(Methyl Cyanide)
Benzene
Chlorobenzene
1 ,2-Di chlorobenzene
1 ,2,4-Trichlorobenzene (TCB)
1 ,2,3,4-Tetrachlorobenzene
Hexaehlorobenzene (HCB)
Biphenyl
(Polychlorlnated Biphenyl s)
Aroclor 1242
Aroelor 1254
Aroclor 1260
Dioxin
2,3,7,8 Tetrachlorodibenzo-p-
dioxin
Qctaehlorodibenzo-p-dioxin (OCDD)
Ethane
1 , 2- Die hi oroe thane
Hexachloroethane
Ethanol
Ethylene
Tetrachloroethylene
Hexachlorocyclopentadiene
Hexane
Hexachl orohexane
Methane
Methyl Chloride
Chloroform
Carbon Tetrachloride
Methyl Ethyl Ketone
Phenol
2,4,6-Trichlorophenol

CH3CN
C6"6
C6H5C1
C6H4C12
Census
C6H2C14
C6C16
C12H10

C12H6.9C13
C12H4C15
C12H3.7Cl6


C12°2H4C14
C1202d8
C2H6
C2H4C12
c2c?6
C2H5OH
C2H4
C2C14
C5C15
C6H14
C6H8C16
CH4
CH3C1
CHC13
CC14
CH3COC2H5
C6H60
CfiHrflsO
Where 1 = EPA's Combustion Research Facility



2
3
1,3
3
1,8


.1

.3 3,8


8
8

2








2
2
2,3,8



(CRF) at Pine
2 = EPA's Destruction of Hazardous Wastes Cofired in

4

4,7

4




7
7
7





4
4
7

7
7

7


4,7
4,7
7

7
Bluff, Arkansa:
Industrial
          Boilers
      3 = EPA's Mobile Incinerator at Edison, New Jersey
      4 = EPA's Controlled Temperature Tower at Cincinnati, Ohio
      5 = EPA's Rotary Kiln Incinerator Simulation at Research Triangle
          Park, N.C.
      6 = EPA's/New York State's Fundamental Flame Combustion Research
          Program at Union Carbide
      7 = Destruction of Hazardous Waste Using Plasma Arc Technology
      8 = Destruction of Hazardous Waste Using Huber's Advanced Electric
          Reactor
                                    231

-------
REFERENCES

1.   Information excerpted from
     various internal  EPA project
     review materials.

2.   Information excerpted from a
     private letter from K.C. Lee
     to C.C. Lee, November 9, 1983.

3.   Lee, K.W.  The Advanced
     Electric Reactor  - A New
     Technology for Hazardous Waste
     Destruction, Journal of Hazard-
     ous Materials.  Publication
     Pending.

4.   Whitmore, F.C. et al.  Systems
     Reliability and Performance,
     Pilot-Scale Incineration of
     Chlorinated Benzenes at the
Combustion Research Facility.
EPA Draft Report, August 1984.

Wolbach, C.D. et al.  Destruc-
tion of Hazardous Wastes Cofired
in Industrial Boilers: Pilot-
Scale Parameters Testing.  An
EPA Draft Report, February 1984,
Project No.7946,

Yezzi, J .J ., et al.  The EPA-ORD
Mobile Incineration System.
Proceedings of the 1982 National
Waste Processing Conference, May
2-5, 1982.

Yezzi, O.J. et al.  Results of
the Initial  Trial Burn of the
EPA-ORD Mobile Incineration
System.  Proceedings of the 1984
ASME National Waste Conference.
               Di sclaimer

 This paper has been reviewed in
 accordance with the U.S. Environ-
 mental Protection Agency peer and
 administrative review policies and
 approved for presentation and publi-
 cation.
                                    232

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       EXPERIENCES WITH SPECIAL WASTE RECEPTION,  INTERMEDIATE  STORAGE
            AND  INCINERATION AT THE HAZARDOUS WASTE  INCINERATION
                             PLANT AT BIEBESHEIM

                         by Dip!.-Ing. Giinter Erbach
                        HESSISCHE INDUSTRIEMULL GMBH

                                   ABSTRACT

The Hazardous Waste  Incineration Plant at Biebesheim has been  In operation
since early 1982. Technically, the plant is designed to  accept, store  and
incinerate hazardous wastes, either solid, semi-solid, liquid  or delivered
in drums, for final  disposal. Capacity: 60'OQO t/a.

Due to the very  strict official regulations on the max.  permissible  emis-
sions, it became imperative to put very strong restrictions, with regard to
flexibility and  efficiency of the cleaning of the flue gases,  on the flue
gas purification plant.  Important for the technical lay-out of the  flue gas
scrubbing plant  was  especially the stipulated separation of aerosols as well
as the regulation that the total amount of arsenic,  lead, chromium,  cobalt
and nickel must  not  exceed 1 rng/m^ and that cadmium  emissions  must not
exceed 0.16 mg/m^ in the flue gas stream. Noxious substances,  such as HC1,
HF and S02» must likewise be separated. Technical, local and environmental
considerations as well as the well-known difficulties in separating  various
heavy metals (i.e. cadmium and mercury) from waste water of a  flue gas
treatment plant, led to the decision to apply the effluent-free flue gas
scrubbing process.

The effluent-free flue gas scrubbing process has been in operation now for
over 3 years. Meanwhile, three basic measurements have been carried  out in
the plant. The results of the measurements meet the demands of the author-
ity. Both the test results and the operation results prove that the  Hazar-
dous Waste Incineration Plant at Biebesheim - especially the integrated
effluent-free flue gas scrubbing process - meets the required  standards of
technology.


The Hazardous Waste  Incineration        Plant PetalIs
Plant, Biebesheim was planned and
built following  a project lanced
by the State of  Hessen for the dis-     Each incineration train consists of
posal of hazardous waste. Techni-       the following plant units:
cally, it is designed to accept
solid, semi-solid, liquid or also
in barrels and drums delivered          - waste reception and  feeding
hazardous waste, including inter-         installation
mediate storage  and  thermal treat-      - rotary kiln with front wall
ment.                                     assembly
                                        - after-burning chamber
In order to achieve  optimum avail-      - boiler
ability of the entire plant, two        - flue gas purification
independently-operating incineration      plant
trains were installed. (Figure 1).      - stack


                                  233

-------
                HIM-VERBRENNUNGSANLAGE BIEBESHEIM
      Bunter feeding System
                    Rotary Kiln
Secondary Combustion Boiler
   Chamber
Reactor + Cyclone
                                                           ID Fan  Sciubber
                                                                          Stack
 Figure 1.
 Rated capacity of each incineration
 train (Figure 2):
                - for liquid hazardous  waste:
                  5.000 to 11.500 t/a
                  (16.730 to 29.300 kJ/kg)
                                    HIM BIEBESHEIM


S
I
3
i

Domestic
Heating Fuel
Liquid Waste
Special
Thin Sludge
Pastes
- 2500 kg/h (
E
c
15 Barrel
+ 350 kg/h -i_
T- 1000kg/h 	
* tOOOkg/h — 1
4.2500kg/h 	
                                                          Domestic Heating Fuel
                                                          350 kg/h
Figure 2.
- for solid and semi-solid
  hazardous waste:
  13.500 to 20.000 t/a
  (10.470 to 18.830 kJ/kg)
               - additional  organically contaminated
                 water without  significant heat
                 value:
                 16'QOO t/a
                                     234

-------
  heat release in the rotary kiln:
  13.97 MW max. continuous rating
  17.44 MW short time peak load

  heat release in the rotary kiln
  and in the after-burning chamber
  combined:
  17.4 MW max. continuous rating
  22.7 MW short time peak load

  total  rated capacity of the
  plant:
  60.000 t/a
Waste Reception
Installation
and Feeding
The waste reception and feeding  in-
stallation consist of:

- crane installation
- feeding hopper
- drum elevator
- semi-solids container and special
  pump for viscous liquids.

The reception and feeding  installa-
tion is designed to enable the fol-
lowing material to be fed  into the
rotary kiln for thermal treatment
through the front wall assembly:

- solid waste from the bunker
- liquid waste from the tank farm
- semi-solid waste delivered in
  barrels or drums
                       wide range and to enable direct  cor-
                       rective action to be taken  in  the
                       kiln. The flow conditions in the rot-
                       ary kiln and the after-burning cham-
                       ber are devised to ensure effective
                       admission of secondary  air  into  the
                       after-burning chamber (Figure  3).
                                          HIM BIEBESHEIM
                                t
                                1400
                              £  1200
                              3  1000
                              2  BOO
                              a)  BOO
                              8-  400
                              i  200
                               (mis)
                             I
Rotary Kiln with Front Wall
Assembly, After-burning Chamber  and
Steam Boiler
The entire combustion  system  con-
sisting of rotary  kiln with front
wall assembly,  after-burning  cham-
ber and steam boiler,  is  designed
to allow for fluctuations in  the
composition of  the semi-solid,
liquid and solid waste within a
                       Figure 3.

                       The steam boiler  system  is  a  natural
                       circulation, waste  heat  recovery
                       design. The boiler  is  placed  down-
                       stream of the  uncooled after-burning
                       chamber. In this  way,  a  clear separa-
                       tion  is established between the
                       actual combustion process  and gas
                       cooling. New in the process in con-
                       nection with the  boiler,  is the
                       tertiary air introduction  assembly
                                     235

-------
in the upper part of the  after-
burning chamber, which  is  an  in-
tegral part of the boiler.

The tertiary air introduction eff-
ects  a shock-like cooling  of  gases
previously completely burnt-out in
the after-burning chamber, from
1.200°C to 800°C. Thereby, the li-
quid  and fused ash particles  and
salts carried in the gas stream are
cooled down, so that it is possible
to reduce the sticking properties
of the fly ash which are known to
develop during high temperatures.
Consequently, sooting-up of the
boiler surfaces is clearly reduced
and the cleaning of the boiler sur-
faces by rapping isessentially fac-
ilitated. Cleaning is accomplished
by vibration of the boiler tubes,
generated by a rapping device loca-
ted at the side of the boiler and
operated automatically.

The low steam parameters  (25.5 bar
and 280"C) were deliberately  selec-
ted to counteract fouling  and con-
sequent high temperature corrosions
which occur in solid waste combus-
tion plants operating with steam
data of higher magnitude.
Flue Gas Purification

The incineration of organic hazard-
ous waste and organically contam-
inated waters in the rotary kiln
with after-burning chamber has long
been technically proven. However,
due to the stricter demands on the
cleaning of flue gas, important new
processes had to be introduced for
separating hydrochloric acid  (HC1),
sulphur dioxide {SC>2), fluoride
(HF), aerosols and heavy metals.

The following maximum permissible
emissions were laid down in the of-
ficial approval for the Hazardous
Waste Incineration Plant at Biebes-
heim:

- material of Class I
  (max. 5 mg/m3)

- material of Class II
  (max. 15 mg/m3)

- total dust
  (max. 75 mg/m3)

- the total emissions of
  Benz(a)pyrene
  Dibenz(alpha,beta) anthracene
  Beryllium and its compounds
  - stated as Be - (max. 0.1 mg/m3)

- the total emissions of arsenic and
  its compounds - stated as As -
  lead and its compounds - stated as
  Pb -
  chromium - VI - compounds - stated
  as Cr -
  cobalt and its compounds - stated
  as Co -
  nickel and its compounds - stated
  as Ni -
  (max. 1 mg/m3)

- the emissions of cadmium must not
  exceed 384 g/d (0,16 mg/m3)

- the gaseous emissions
  chlorine compounds - stated as
  chloride (max. 100 mg/m3)
  fluoride compounds - stated as
  fluoride - (max. 5 mg/m3)

- carbon monoxide (max. 100 mg/m3)

- emissions of carbon in combustible
  organic substances (max. 50 mg/m3)

The presence of aerosols, in partic-
ular also of heavy metal-oxides such
as cadmium (Cd), lead (Pb), chromium
(Cr), copper (Cu), vanadium (V) and
zinc (Zn) in the flue gases of ther-
mal treatment plants for hazardous
waste, has been confirmed in various
tests.
                                     236

-------
It was known that the absorption of
acids, gaseous noxious substances
and also dust particles of not-too-
small grain size, can be effectiv-
ely accomplished with relative ease
in flue gas scrubbing processes.

Considerably more difficult to
solve was the separation of aero-
sols from the flue gas. In order to
achieve this, a "conditioning" of
the aerosols was required, result-
ing in enlargement of the particles
and so simplifying the separation
procedure. This conditioning was
attained by:

- agglomeration of numerous aerosol
  particles to larger particles

- adherence of water to these
  single particles

The separation of aerosols makes it
possible to remove fine dust and
metal oxides with an efficiency
rate of at least 99.5%.
In order to prevent the problems,
when utilizing a flue gas scrubbing
plant, directly shifting from the
air to the water, an extensive and
expensive-to-operate waste water
treatment plant is required to elimi-
nate the heavy metals from the waste
water. It was known, from operation
of sewage treatment plants, that
especially the separation of heavy
metals - mercury (Hg) and cadmium
(Cd) - from the waste water, is
extremely difficult. Therefore - and
in view of the local possibilities of
effluent discharge - an effluent-free
flue gas scrubbing process was selec-
ted for the Hazardouzs Waste Inciner-
ation Plant at Biebesheim.
Description of the Process

A simplified flow sheet illustrates
the process basics of the effluent-
free gas purification system
(Figure 4).
              Flue Gas
                              HIM 3IEBESHEIM
                                 Process Principle
                                       Water
          Clean Gas
                                         LJTf
                                                 6
                                                 6
Figure 4.
                                    237

-------
In a first treatment  stage,  after
leaving the  boiler  at a  temperature
of 250 - 280°C,  the flue gases  pass
through the  reactor (1)  from the top
downwards in parallel  flow with the
finely atomized  liquid from  the
scrubber using a centrifugal  atom-
izer. The required  heat  for  evapora-
tion of the  scrubbing liquid  is
extracted from the  flue  gas.

Thereby, the flue gas is cooled from
250 - 280°C down to 160  - 180°C. In
the reactor, a portion of the acid
noxious substances, such as  HC1, HF
and S02 already  adheres  to the  fine
dust by settling, i.e. is
neutralized.

At this stage, the  dried solids, such
as salts - together with fine dusts
and heavy metals -  are largely  sep-
arated from the  flue  gas in  the re-
actor and in the following cyclone
(2). Following the drying process,
the flue gases enter  the scrubber by
means of an induced draft fan.
The flue gases are cooled  and  at the
same time already in the quench (3),
a strong absorption sets in of the
gaseous noxious substances HC1 and
HF. Meanwhile, a first conditioning
takes place of the aerosols present
in the flue gas and of the ones de-
posited by condensing during the
cooling process. By separating acid
gas components, the pH-value of the
scrubbing liquid levels to 0 - 1.
The flue gases, cooled and pre-
conditioned in the quench, pass to
the second scrubbing stage (4), where
the actual absorption of HC1, HF  and
the cooling down to the water dew
point of approx. 70°C takes place.
The pollutants HC1 and HF are thereby
separated, only leaving traces. The
complete extraction takes place in
the third scrubbing stage (5).
Besides the absorption process,
especially that of HC1, HF  and
partly also of S02, the dust parti-
cles not caught by the cyclone, are
extracted in the second stage.
The conditioned flue gases then
pass on to the third, scrubbing
stage (5), via a droplet separating
unit (6), which prevents the scrub-
bing liquor from being carried
along.
In a venturi-intermediate staqe
located upstream of the third
scrubbing stage, the suspended mat-
ter (aerosols) is pre-conditioned
in such a way that it can be bound
to the scrubbing liquor by means of
24 ring-jet elements which were
especially devleoped for this  pur-
pose. Because of the extremely good
absorption quality of the ring-jet
stage (5) for gaseous material,
this scrubbing stage also achieves
an effective separation of SOg-
Caustic soda (NaOH) is added as
neutralizer. After leaving the ring
jet, the flue gas, together with
the spray of the scrubbing liquor,
passes to a short layer of filler
material packing, which serves to
agglomerate the fine liquid drop-
lets so that they can be thoroughly
separated by means of the directly
following droplet separating unit.
Subsequently, the flue gases
scrubbed free of gaseous noxious
substances (HC1, HF and S02), fine
dusts, aerosols (salt-condensates
and heavy metal oxides) as well as
liquor droplets, pass on to the
stack.

Due to the satisfactory extraction
of liquor droplets and aerosols,
re-heating of the cleaned flue
gases is not necessary.
                                    238

-------
Accompanying Measuring Programme
In line with the promotion of this
project by the German Federal Min-
istry for Research and Technology
(BMFT), an accompanying test and
analysis programme is being carried
out at the plant. A material and
mass balance will indicate possible
effects on the environment by the
hazardous waste incineration plant
which will be minimized by an
appropriate optimizing process.
Official measurements to determine
the degree of separation of the
noxious substances have been
carried out in the meantime, show-
ing the following results.
Metals


Arsenic (As)
Beryllium (Be)
Cadmium (Cd)
Cobalt (Co)
Chromium (Cr)
Copper (Cu)
Mercury (Hg)
Nickel (Ni)
Lead (Pb)
Zinc (Zn)
TUH
Measure-
ment
in mg/m3
ti.N.)
0.03
0.02
0.09
0.01
0.05
0.04
0.006
0.02
1.67
1.86
1.NUKEM
Measure-
ment
in mg/m3
0.03
0.02
0.05
0.03
0.06
0.5
0.03
0.06
3.0
7.1
2.NUKEM
Measure-
ment
in mg/rrr
(i.N.)
<0.03
<0.02
0.06
<0.03
0.12
0.13
0.05
<0.06
0.70
0.70
                                       Table 2.


HCl
HF
SO2
CO
C (organic!
NOx (calculated
as NOa)
Dust, total
Dust, class 1
Dust, class II
Cd
Approved
Value
in mg/m3
(i.N.f.)
100
5
200
100
50
_
75
5
15
0.16
1.NUKEM
Measure-
ment
in mg/m3
(i.N.?.)
15
0.03
100
6
3
40
30
3.5
10
O.iO
2.NUKEM
Measure-
ment
in mg/m3
O.N.?.)
9
0.5
115
15
-
60
12
1.3
2.5
0.06
TA-Air
Value
in mg/m3
(i.N.?.)
100
5
-
50
50
-
75
20
50
—
                                       Operat i ng Experi ences
                                       The Hazardous Waste Incineration
                                       Plant at Biebesheim has been operat-
                                       ing since early 1982. As the flue gas
                                       scrubbing system of the plant has
                                       neither an emergency stack nor a by-
                                       pass, the plant can only be operated
                                       when the flue gas cleaning system is
                                       available. There were no breakdowns
                                       in the flue gas cleaning system which
                                       could have considerably impaired the
                                       availability of the Hazardous Waste
                                       Incineration Plant at Biebesheim.
Table 1.
The following chart shows a compar-
ison between the approved measured
values and the TA-air values
(German Clean Air Act - TAL 1974):
In 1982, the first year of operation
- the year of start-up and the opti-
mizing period of the plant - approx.
30.000 t of hazardous waste was pro-
cessed: in the following years, 1983
and 1984, approx. 52.000 t resp.
60.000 t .
                                     239

-------
A larger deviation resulted only in
the costs for repair  and mainten-
ance. This was due to the fact that
the official authorities demanded
an operating temperature in the ro-
tary kiln of 1200°C which  is
effectively necessary for a satis-
factory complete combustion. This,
however, led to an attack by chem-
ical and mechanical action on the
kiln refractory. Therefore in place
of the one-layer refractory, a 1.5
times thicker refractory layer is
required per year.

Furthermore, the variety of waste
material to be incinerated has
greatly changed, compared with
assumptions at the time the plant
was designed. This especially
refers to solid hazardous waste. In
1984 alone, the delivery of solid
waste has increased by 100%.

Summing up, it can be stated that
the concept of the Hazardous Waste
Incineration Plant as well as the
effluent-free flue gas cleaning
system at Biebesheim is success-
ful. All residues produced during
combustion, such as slag, fly-ash
and fine dust (salts and metals),
accumulate in a dried condition.

The slag and fly-ash can be
deposited on an industrial waste
landfill. The salts, fine dusts and
heavy metals, i.e. all residues
from the reactor, must be packed in
special containers because these
are mainly water-soluble salts
which must be taken to an under-
ground deposit (Herfa-Neurode). In
order to reduce the higher costs
compared to storage on an indus-
trial waste landfill, tests are
carried out to determine whether,
by special measures - i.e. by
solidifying - it might be possible
to deposit these residues on a
normal industrial waste landfill.
Prospects
Due to the increased amount of hazar-
dous waste, it is necessarsy to ex-
tend the plant by a third train. The
experiences made during the present
operation of the Hazardous Waste
Incineration Plant at Biebesheim will
result in important technical im-
provements which will be considered
for the extension of the plant:
- Increasing the diameter of the rot-
  ary kiln, whereby, with regard to
  the actual waste situation, a high-
  er throughput of solids will be
  achieved. At the same time, im-
  proved access to the burner and
  lances in the front wall assembly
  is achieved.
- Installation of an electrostatic
  precipitator instead of a cyclone
  for dust separation.
During operation, it became obvious
that the solid particles formed in
the reactor are so fine that a dust
separation in the cylcone did not
prove to be successful and the dust
separation was transferred from the
cyclone to the scrubber. This
increased dust accumulation in the
scrubber has, in no way, influenced
the functioning of the scrubber: it
has, however, led to an increased
maintenance in the circulating pumps
which could be decisively reduced by
installing an electrostatic precip-
itator.
                Di sclaimer

  The work described 1n this paper was
  not funded by the U.S. Environmental
  Protection Agency.  The contents do
  not necessarily reflect the views of
  the Agency and no official  endorse-
  ment should be inferred.
                                    240

-------
          DEVELOPMENT OF  PREDICTIVE MODELS  FOR THE ASSESSMENT OF
                   POLLUTANT EMISSIONS FROM INCINERATORS

                               Se 1 im M, Senkan
                    Department of Chemical  Engineering
                     Illinois Institute  o£  Technology
                         Chicago, Illinois  60616 USA

                                  ABSTRACT

         Considerable  progress  has been made over the   recent   years
    both on the experimental and theoretical  aspects of  flame  combus-
    tion of hydrocarbons  bearing he t e r o-a-t oms such as halogens  (espe-
    cially  chlorine) nitrogen,   and sulfur.   In particular,  the emer-
    ging  results  from   carefully controlled studies  of   laboratory
    flames  with the aid  of  molecular beam  mass spectroscopy  (MBMS)  is
    leading to the establishment of better  and more detailed  insights
    of   the  chemistry   of  combustion taking  place  in   incinerators.
    These developments,  combined with the  availability of  fast  compu-
    ters,  and reliable  thermochemica1 kinetic data and accurate esti-
    mation methods  is  allowing us to develop comprehensive   chemical
    kinetic  models describing  the detailed  destruction mechanisms  of
    the   principal  organic  hazardous  components  
-------
 q u e n t   emissions  from  incinerators
 as   pollutants.   In  fact,   in  many
 applications   the   potential  emis-
 sions  of these  intermediates appear
 to   be of greater  concern  than   the
 principal organic  hazardous consti-
 tuents (PQHCs)  in  the feed  streams
 from  public health  point  of  view.
 Fur   example,   highly  tonic  COCI
 (4,6)   and  HCN <12)fo rm as  in t e r-
 med tat as during the  incineration  o£
 chlorinated and nitrogenated hydro-
 carbons, respectively.  It  is there-
 fore   clear that  the   emissions  of
 products  of incomplete  combustion
will   have  to  be  considered as  an
 integral  part  of   the  evaluation
 process   for the scientific  asses-
 sment   of the performance  of  inci-
 nerators  in the future,   and  thus
 for  the  successfull  utilization  of
 this  technology.

     In  recognition   of   this  need
our   laboratories have pioneered  a
 fundamental  combustion/   incinera-
 tion     research  program   directed
 towards  developing pr ed i c t i ve  che-
mical  kinetic models  that will   be
useful   for the rational assessment
pollutant emissions  from   incinera-
 tors.  In our current  research  par-
 ticular  attention  is  given to study
 the    incineration  of  chlorinated
hydrocarbons (CHC) because of their
large—scale  presence  in    process
waste  streams,  and because of their
 Significantly . different combustion
characteristics  when compared  to
other  hetero-atom  bearing   hydro-
carbons.   For example,  chlorinated
hydrocarbons  inhibit   hydrocarbon
oxidations  in flame s  (18),   exhibit
 two—step  combustion  reactions  with
 tha  formation of highly  toxic  int-
ermediates  such as COCI  even under
oxygen rich conditions (4,5,6)   and
greatly   promote  the  formation  of
poyloyclic   aromatic   hydrocarbons
and  soot  in flames (15).

     In this communication,   some  of
the  recent  experimental and  theore-
 tical  developments on  the  incinera-
tion   of  model   chlorinated   hydro-
carbons   arc  presented,    and   the
general   principles  involved in de-
veloping p red ic t i ve models are  des-
cr ibed .
                                     242
 EXPERIMENTAL APPROACH

     In  order  to   develop  rational
 chemical kinetic  models with predi-
 ct t i v e capabilities  the chemistry  of
 incineration  must  be known with  as
 much detail as possible.  Otherwise,
 the  process of constructing a  com-
 prehensive  model  becomes impracti-
 cally cumbersome  and   camples.   The
 most straight forward approach  for
 this  is  to  determine  first   the
 relative  orders   of  formation  and
 disappearance of  many of  the impor-
 tant  intermediates during  combus-
 tion,   in  which   the  presence   of
 stable  as well as  radical  species
 must  also  be  considered.    These
 requirements  inevitable   neecessi-
 tate  the  use  of  molecular  beam
 sampling  methods  (to preserve   the
 integrity of flame  radicals)   coup-
 led   with 1ine-of-sight mass   spec-
 troscopy .

     Molecular beam mass spectrosco-
 py (MiMS)  is a highly versatile and
 powerful   experimental    technique
 which   allows  the direct   determi-
 nation   of  the   chemical   identity
 and   relative concentrations  of es-
 sentially   all   the    species     in
 flames,   including  the flame radi-
 cals in  a single  experiment.   As   a
 result,   MBMS  is most  suitable   in
 identifying   the  detailed  chemistry
 and  the  relative  rates  of  formation
 and   destruction  of   products    of
 incomplete  combustion,  during inci-
 neration.

     Recently  we  have  completed the
 construction of a  state—of-the—art
molecular   beam  mass   spectrometer
 system  for   flame  analysis,    a.nd
 began  characterizing  the  incinera-
 tion chemistry of chlorinated  hyd-
 rocarbons  (6).   Other  components  in
 our   research facility  include  pre-
 cision flat  flame burners  (to gene-
 rate one dimensional  flames), a gas
 flow  regulation  system   utilizing
 sonic  orifices 
-------
     One dimensional  flat  flames  are
 stabilized   o v&t & 5   cm.   dianeter
 flame holder which is  also shrouded
 with  an  inert gas.  The  burner   is
 mounted   on  a vertical   translator
 which  is  motor driven   and  under
 computer  control.    The   molecular
 beam sampling  system as well as  the
 mass spectrometer are  mounted above
 the  burner for 1ine-of-sight detec-
 tion  of  the  species  as   shown   in
 Figure 1.
 i n I e rino 1 ec u I a r collisions and   t ft as
 to  preserve  the  identity of   flame
  Pith of the
  Molecular Bean
                    Quartz Sampling Cone

                      Flarae


                      Burner
                      Burner
                      Movement
                      Hechanisn
Ftgure 1. sclwutlc of ttw Molecular Beam Hass Spectrometer System
    Flame  sampling  is  accomplished
by  withdrawing   gases from   within
the   flame using  a   conical   quartz
cone  with  a cone  angle of  about  70-
90  degrees and with an orifice   at
its   tip  having a diameter of about
30  microns.  Upon  passing   through
the orifice,   the gases  accelerate
and   form  a supersonic jet and  ex-
pand  into  the  first  vacuum stage of
the   MBMS   system which is kept   at
about  10   -10~  torr by a  1000 It/s
turbomoleeular pump.  This level of
vacuum  is  necessary  to  minimize
 r ad i ca1s
 detect ion.
 expand ing
 ob t a iiied
 su i tab 1 y
             for  mass   spectroscopic
              From   the  core   of   the
             jet a molecular beam  is
            using  the   skimmer   cone
            placed   above the   quartz
 sampling  cone.  The molecular   beam
 is  ionized   using  electron   impact
 ionization,   pass  through the  quad —
 rupole mass  filter/ and the  approp-
 riate signal  intensities are  detec-
 ted.   The  molecular  beam  is   also
 modulated  at  a fined  frequency  in
 the  range   150-400 Hs  for the   im-
 proved detection of species  at   low
 concent rat ions.

     Data   acquisition  is accomplis-
 hed by means  of an    ana 1og/digital
 conversion   board.   The computer  is
 programmed to  read  the  beam   signal
 intensity  of  the molecular ion  that
 is  being  monitored  directly   from
 the  lock-in  amplifier  and to   move
 the  burner  relative  to the   quarts
 sampling   cone in  a   predetermined
 sequence   to  generate  species   pro-
 files  along  the flame.   These  spe-
 cies   profiles  are   then  used  to
 identify   the   relative  order    of
 formation  and  destruction of   the
 intermediates  in the mechanism, and
 this   information  is   subsequently
 used  to develop  detailed models.

     In  Figure 2,   the   temperature
 and    some  representative  species
 intensity  profiles measured  along
 an   oaygen rich  C  HC1  -O -Ar   flat
 flame  are   shown.   These  profiles
 clearly illustrate  the  power of  the
 MBMS   technique  in providing quali-
 tative  as  well   as    quantitative
 information  on  the chemistry  and
mechanism  of  incineration  of  ha-
 zardous materials.   These  intensity
 profiles  subsequently are  converted
 into   mole  fraction  profiles    by
using  calibration-gas mixtures. The
 temperature  profile  was   measured
using  a SiO  coated thermocouple.
METHODS OF DATA  ANALYSIS

    The  experimentally   determined
species  concentrations   and  their
profiles are  then used  to construct
detailed  chemical  kinetic  models
describing the  incineration of   the
                                         243

-------
               .3.) w?ui Mstanct . However,
such  data for  many of the interme-
diate  and radical  species are  not
generally  available,   consequently
 for   those  species   the  necessary
 thermochemical    information    must
again be  estimated using  theoreti-
ca1  me thods (3) .
                                        244

-------
                                                                     Table  I
                               Detailed Chemical  Kinetic Mechanism of  Combustion  of  Trichloroethylene
                                          (ksATnexp(-E/RT, in cal.,s,cc»mole units)
ro
                         Reaction
                                   A
Reaction
                                                                                                             A
     CIHCLJ»M.CIIICLJ«Ct«H
     C DtCt3*H-C2Ctl«HCL»H
     C2HCL3.M-C2H<:t.Ct2.H
     C2l(Ct3 .CL-C1IICL«
     C2HCt4.O2.C2CM.HO2
     C2HCL4.CL2-C2IICt3.Ct
     C2HCL3»H-C1HC14»CI.«H
     C2IICtJ.H-CCt3.CHCt2 .H
     C2HCt3.Ct-C2Ct3.HCt
10   C2CI,S«H!.C2C!.4»Ct,*H
tl   C2Ct!*O2-CZCt«.CtO2
II   C2HCt3.Ct.C2HCt2.CLl
U   C2HCtJ*Ct-C2CH*I!Cl
14   C2HCt3.OIUC2Ct3.IIZO
15   C2HCL 3»Olt«CHCtltCHQCl
14   CIHCL3tCtO.CHCtl»COCtl
17   C2HCt3.CLO.CCt3.CHOCt
II   C2IICL3 .O.CHOCL.CCL2
If   CZHCL3»O.COCE.1»CIICL
20   C2HCL3.H02.CZCL3.HJ02
21   C2CH«H«C2Cl.l*Ct.*H
21   C2Ct4.0-COCt2.CCt2
23   C2CL4«Ol(.C2Ct3>KOCL
24   C2CL1 »OH.CIICL2 t COCLI
23   C2CL4tCLOaCCL3tCOCL2
24   C2CL4•CL.CZCL3.Ct2
17   C2CL3CLl.H

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CI.2tM-2CL»n
ct2 .H..HCL .CL
cti«o.cto*ct
IICL .M-IHCL .H

IICL.H-.HZ t CL

HCL.O-OH.CL
ClQl*Cl-Ct,O«e:L0
CLO»O«Ct»O2
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CO«O»H-CO2.H
CO.H02.C02 .Oil
CO»CIO.CQ1«CI
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1I.02.0II.O
H2.O.OH.H
O.H2O-2OH
H.HZO-OH.H2
H2O.M-H*Oli.H
n.02 .H.HOZ. M-
O»OH4H.HO2»H
H02.O-.02 .OH
1I2O2 .M-2O1I .H
H2O2»Ct=IIO2»HCt
1102 .Ct=,OH. CtO
OZ.H2-ZOH
OiH.HiOtUH
O.O.M-02 in
H2.M-2II.M
H.HO1-IOH
H.HOZ. OZ. 112
1102 .1IO2.II2O2 lOl

H.H2OZ-,IIO2 .112
H2O2 .OH.H2n.H02
\
.OOEU
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-------
     Thti rmophy s i ca. 1  properties, such
 as  tha  spacias diffusivities,   the
 mixture  viscosity and  conductivity
 are  normally  calculated  using well
 established    techniques    (13,17).
 Such   properties are  important   for
 accurate  simulation  of   flames   in
 which  transport via diffusion is  as
 important as  convection.
      In  Figures 3 and 4   calculated
 species   profiles   along  an  oxygen
 rich C HCI   flate flame are presen-
 ted  together  with those   determined
 in experimental flames.   As evident
 from  these  figures,   the  model pre-
 dictions  are  in excellent  qualita-
 tive as  well  as quantitative  agree-
 ment with the  experimental  measure-
 ments. This agreement is  particula-
 rly  important  in view of  the  very
 fundamental nature  of the   proposed
 mechanism shown in Table  I.
  0,125


  8 109


S 9.975
M
C
I*.
I o.ose


  8,925
0.000
9.0!
e.ae
   0.089  8.925  0.859  9.873  8.188 8.125  0.153 9.175
                   Olsunei »1<»9 fljet, as.
     noun 3. CiIculttKJ (Huts) *n« Meisurtd (symbols) Sseeles Hole
          Friction Profllts Along an Oxygen Rtcn CjHCIj Flat Flam*.
DISCUSSION
     As   evident  from  the  mechanism
presented  in Table I,  the oaidation
of  C.HCl   involves the  formation of
a  large  number  of  stable as well as
radical   intermediates.   The  stable
intermediates,   which  include   spe-
cies  such as C  Cl ,   COC1  ,   CC1  ,
and  CHC1   constitute   the  obvious
products   of incomplete   combustion
   0 -MO  13.025 8.359  8.975  8.109  9.123  3. 159 9.175
                 Q1sunc« along flint, ».
    Figure 4. Calculated (lines) and Measured (symbols) Species Hole
          Fraction Prof)1*s Along an Oxygen Rich CjHClj Flat Flame.

  that  may  be emitted  from  incinera-
  tors   burning    t r i ch 1 o r oe t hy I ene .
  Less obvious products  of  incomplete
  combustion  are   the   recombination
  products  of some the  flame radicals
  via  reactions such  as:
        CC1
                                                              CCi
                                                      CHC1
                                                                Cl   = = =
                 CC1
      Therefore,   Table  I  because  of
  its  comprehensive nature would  be a
  rational   starting point to   assess
  the   potential    emissions of   pro-
  ducts of  incomplete combustion  from
  incinerators,   and  to  predict   the
  changing  nature  of these pollutants
  under  different   operating   condi-
  tions. This will  be accomplished by
  simply conducting numerical  incine-
  ration   experiments,    rather   than
  undertaking expensive  test-runs.

      Although   the  construction  of
  smaller   sets  of  reactions   may  be
  desirable from  an engineering  point
  of   view,  this  may greatly   reduce
  the   range of  applicability  of   the
  model (  i.e.  temperature, pressure,
  and   composition range).  For  exam-
  ple,   an elementary reaction  which
  may   be   unimportant   under   oxygen
  rich conditions  may become estreme-
                                          246

-------
ly    important   under  ouygen   lean
conditions.  Thus deleting  that  rea-
ction   from  the  mechanism  based   on
oxygen  rich  esperiments would  gre-
atly  diminish  the overall  utility
and   the  predictive capability    of
the mechanism.

    Consequentlyi  predictive models
inevitably   should involve a   large
set of  reactions for safety.   Furt-
hermore,   it  must  be  noted   that
since   calculation  times  are   not
dramatically  influenced by the num-
ber of  reactions,   instead they  are
greatly  influenced by the  number  of
species   in   the  mechanism,   large
sets  of  reactions  are indeed accep-
table in  these  studies.

    One   of   the reasons  why  such
detailed  mechanisms are successfull
in simulating combustion/  incinera-
tion  processess is largely due   to
the   fact  that  only a few  of   the
reactions  in  the detailed  mechanism
are   important   in influencing   the
overall   behavior  of the   incinera-
tion  process under a given set   of
conditions.  Therefore, the need  for
highly  accurate  rate  infor ma t i o n
exists  only  for   those   dominant
reactions  in the   mechanism.    For
the remaning  reactions,  the use  of
approximate   rate   data is  usually
sufficient.  This   is an   important
observation  because  e K p e r i me n t a 11y
measured  rate data are not availab-
le for many  of  the elementary  reac-
tions shown  in Table I,  consequen-
tly   they  had  to   estimated  using
theoretical  methods.   However,   in
spite of  this the  model predictions
are   in   reasonable agreement  with
the experimentally determined  spe-
cies  profiles.

    The   important reactions in  the
mechanism can also be identified  by
undertaking   numerical  sensitivity
studies.   Following their  identifi-
cation,   these  sensitive   reactions
may be  isolated  and studied indivi-
dually   for  the  accurate determina-
tion  of  their  rate coefficients.
 ACKNOWLEDGEMENTS

      This research was  supported   in
 part   by funds from  the  U.S.   Envi-
 ronmental  Protection Agency,   Grant
 No:   R81Q381-01  and   the   Illinois
 Institute  of  Technology.

 REFERENCES

  1. Bahn.G.S.,  NASA Report  CH-2178
      ( 1973) .

  2. Baulch,D.L.,  Dusbury,J.,and
     Grant,S.,  J.Phvs. Chem.Ref.
     Pa t a,  v.10.  Supplement  1,  1981.

     3. Benson,S.W.,    Thermochemica1
     Kinet ies. John Wiley, N.Y.  1976.

  4. Bose.D.,  and  Senkan,S.M.,  Con-
     Jru s t .  Sci .Tech. .   v.35,  p . 1 87
     (1983)  .

  5. Chang,W.D.,    and   Senkan,S.M.,
     Comb us  t .   Sci .  Te ch ._, 43 .   p . 49
     (1985).

  
-------
13,  fU'.d.H .,: . ,   Frausvii ts , J .M . ,  and
     Sherwood,T.K.,    The  Properties
     g f   GA se s and  Li gu Id s.,   McGraw-
     Hill,  New York  1977 .
14,  Senkan,S.M.,  Combust.Sci.Tech.,
     V.38,  p.19?  (1984).

IS,  Senfcan.S.M. »  Eobinson,J.M.,  and
     Gup t .d , A . K.. ,  Comb us t.F I ame , ». 49.
     p .305  < 1983) .

16.  StulI.D.R.,  and Prophet,H.,Eds.,
     JANAF   Tables,    NSRDS-N1S    37,
     1971 .
              Disclaimer
This paper has been reviewed in
accordance with the U.S. Environ-
mental Protection Agency peer and
administrative review policies and
approved for presentation and publi-
cation.
17. Svehla.R.A.,   NASA Tech.  Report
    R-132 < 1962) .

18. Valeiras,  H.,   Gupta,A.K., and
    Senkan,5.M.,     Combust.    Set.
    Te eh ....  v.3&,  p. 123 <1984>.

If. Westley.F.,   National  Bureau of
    Standards    Report,    NSDRS-NBS
    67,  1980 .
                                    248

-------
            REACTION MECHANISM OF OXIDATION OF CHLORINATED METHANES

                  D. L.  Miller, M. Frenklach and R.  A.  Matula
                        Hazardous Waste Research Center
                            College of Engineering
                          Louisiana State University
                             Baton Rouge,  LA 70803


                                   ABSTRACT

     Safe  destruction  of  hazardous  materials  has  become  one  of  the  major
concerns   of  our   society.     Of   particular   importance   are   chlorinated
hydrocarbons,  which are  major  constituents  of  many  industrial  wastes.   An
effective way  for the destruction of  chlorinated  hydrocarbons  is  incineration,
which uses a flame environment to destroy  these materials.  In  order to suggest
appropriate  operating  conditions in  existing incinerators  and  to ensure  the
effective   destruction   of    hazardous  wastes,  one   needs  to  develop   an
understanding of the physical  and chemical  phenomena which govern  the  process.
The  combustion chemistry of  chlorinated  hydrocarbons,  the principal  factor
of the incineration process,  is  not well established.   The goal  of our current
research  program  is  to  develop an  understanding  of this  chemistry.   This
paper presents results of our modeling efforts directed towards the elucidation
of  the   chemical   reaction   mechanisms   for  the  oxidation  of   chlorinated
hydrocarbons.

     The  initial  efforts  of  our program  are  focused  on  detailed  chemical
kinetic  modeling  of  the oxidation   of  chlorinated methanes,  simulating  the
oxidation  processes occurring  at  the experimental  conditions of  Miller  et
al.   (1983).   In   that   work,   stoichiometric  mixtures   of   chlorinated
methanes/oxygen in  argon were  studied behind reflected shock waves at  1.8
atm. over the  temperature range  1300-1600K.   Monitoring pressure,  the  ignition
delay  times were  determined.   The  objective of  our   modeling  is to  develop
a  reaction  mechanism which would predict  the experimental  observations.   The
development  of the  reaction mechanism  follows  the  procedures  established
previously (Miller and Frenklach, 1982, and Frenklach,  1984).

     The modeling  results for methyl  chloride and dichloromethane  were  reported
recently (Miller et al., 1985).  This paper presents the results  for chloroform
and  carbon  tetrachloride.    Discussion  of  reaction   mechanisms  composed  of
elementary  chemical reactions  and  the  computational  prediction,  using  the
developed  mechanisms,   of  the  corresponding  experimental   observations  are
presented.    Comparing    the   mechanisms   for   methane,   methyl  chloride,
dichloromethane, chloroform  and carbon tetrachloride the influence  of increased
chlorination of methane  on the reaction mechanism is discussed.
                                      249

-------
                             TIER  4  DIOXIN  TEST  PROGRAM STATUS

                 Miles, A.  J.,  Parks,  R.H., Oberacker, D., Southerland, J.

                                        ABSTRACT

     The paper  discusses the status of Tier 4 of the National Dioxin Study and focuses
 primarily on  the identification and selection of candidate combustion sources for the
 test program.   No  laboratory results  will  be presented.

     The Tier 4 program addresses the broad questions do combustion sources emit
 significant quantities of  dioxin?   If so,  how much and what are the health risks
 associated with these emissions?

     The approach  taken to address  these questions was divided into several steps.
 First, an extensive literature search was  conducted, and all available dioxin emissions
 data were summarized.  The information was then analyzed to attempt to identify factors
 which would affect dioxin  emissions from combustion sources.  The analysis Indicated that
 the following factors could have an effect on dioxin emissions.

       -  Presence of dioxins  in the  feed;
       -  Presence of dioxin precursors in the feed;
       -  Chlorine in the  feed;
       -  Combustion conditions (temperature, oxygen level, etc.); and
       -  Feed  processing.

     The analysis also indicated that combustion of waste products as opposed to fossil
 fuels was more  likely to form dioxins.  Using the factors listed above, in conjunction
with a list of major combustion source categories and the available dioxin emissions data
 base, a ranked  list of combustion source categories with the potential  to emit dioxin was
 developed.

     In conjunction with the development of the list, a source test program was devised.
 Ten to twelve sources are  to be tested for dioxin emissions using a Modified Method  5
 sampling train  including an XAD-2 resin trap.  The test program also includes sampling of
 feed materials  and collected particulate;  continuous monitoring of CO,  CO,,  0,,  and  THC;
 and acquisition of operating data over the period of each test.   In addition, some
 40 sites were selected for ash sampling and analysis to broaden the dioxin data  base.

     Site selection for the test program began in August 1984, and the  first test  was
conducted in October.  Two tests were conducted in November,  and subsequent tests  were
 conducted in December and January.  All  testing will be complete by June of 1985.  No
 results from the test program are available.
INTRODUCTION AND PURPOSE

     The Air Management Technology Branch
(AMTB) within the EPA's Office of Air
Quality Planning and Standards (OAQPS) is
responsible for the development and imple-
mentation of a source testing program for
Tier 4 of the National Dioxin Study.
Technical guidance for the source test
program is provided by IERL/HWERL in
Cincinnati.  The purpose of Tier 4 is to
assess combustion source emissions of
polychlorinated dibenzo-p-dioxin (PCDD),
with a focus on the most toxic isomer -
2,3,7,8-tetrachlorodibenzo-p-dioxin
(2,3,7,8-TCDD).  Combustion source
emissions of polychlorinated dibenzofuran
(PCDF) will also be addressed in  this
study.

     Radian Corporation,  under task  order
contract, is providing support to the
AMTB by collecting and reviewing  available
literature data on emissions of PCDD's
and PCDF's from combustion sources.  In
addition, Radian will  perform PCDD
                                        250

-------
emissions tests on twelve combustion
sources.  The samples will be analyzed
by EPA laboratories for PCDDs and P.CDF's.
The source test plan addresses the
following questions:

     1.   Which combustion source catego-
ries emit PCOD's (and PCDF's) to the
atmosphere?

     2.   What range of concentrations
and quantities of PCDD's {and PCDF's)  are
emitted from these source categories?

     3.   What are the estimated health
risks associated with these emissions?

     This paper describes development  of
the source test program including selection
of candidate combustion sources.   In
addition, the status of the program  as of
April 1985 is discussed.  Further details
of the program can be found in the project
plan (1), the initial literature  review
document (2), and the sampling guidance
manuals (3, 4) developed for the  program.

     Dioxins are members of a family of
organic compounds known chemically as
dibenzo-p-dioxins.   All  dioxin compounds
have a three ring nucleus containing two
benzene rings interconnected by a  pair of
oxygen atoms.  The structural  formula  of
the dioxin nucleus and the convention
used in numbering its substituent  posi-
tions are shown in Figure la.   Chlori-
nated dioxins can contain up to eight
chlorine atoms and 75 different chlori-
nated dioxins are possible.   Each  congene
has its own physical, chemical, and
health effects properties.
with varying physical, chemical, and
health effects properties.
               Figure  la.

     Dibenzofurans  are a group of organic
compounds that have a  similar structure
to the dibenzo-p-dioxins, except that the
two benzene rings in the nucleus are
interconnected with a  five member ring
containing only one oxygen atom (Figure
Ib).  Theoretically, the chlorinated
dibenzo furan group can contain up to
135 rHffprwit structural congenerss each
         oriQ
          Figure Ib.
     Of all the PCDD's and PCDF's 2,3,7,8-
TCDD has received the most attention.
However, in general, 2,3,7,8-TCDO repre-
a small fraction of the total  PCDD found
in combustion source emissions.  In
addition, PCDF emissions can exceed
2,3,7,8-TCOD emissions by two  to three
orders of magnitude.  For some sources
PCDF's contribute significantly (over
80 percent) to the health risk associated
with combined PCDD and PCDF emissions.
APPROACH AND SCOPE OF THE  TIER 4 STUDY

     The Tier 4 program was divided into
three phases:  (1) the literature evalua-
tion and design of a  test  program and
(2) the source test program including ash
sampling, and (3)  data summary and
analysis.

     The first phase  of the Tier 4 study
was accomplished in three  general tasks.
The first task was to obtain and review
the available literature on PCDD emissions
from combustion sources.   Over 100
published and unpublished  reports were
obtained.  In addition, contacts were
made with key individuals  to identify
recently performed or ongoing studies
that could be used to supplement the data
base.  The second  task was to develop a
ranked list of source categories with
potential to emit  PCOO's.  The criteria
used to develop the ranked list was based
on information obtained from the litera-
ture review.   The  final task was to
develop a testing  program  to assess PCDD
(and PCDF) emissions  from  combustion
sources.   The results of these tasks are
summarized below.

PCDD Emissions Data
     A review of  the literature has
produced a  list of  12 broadly defined
source cateoories for which some dioxin
                                       251

-------
emissions data has  been collected.
Table  1 lists sources for which  published
dioxin data could be found and  summaizes
the measured TCDD concentrations.
Although the National Dioxin  Study is
focusing on 2,3,7,8-TCDD, most  of the
data found in the literature  addressed
TCDO and total PCDO.  Since 2,3,7,8-TCDD
data are limited, TCDD was used  during
the evaluation of the data base  as  the
best indicator of 2,3,7,8-TCDD  emissions.
with over 100 ppm chlorine and normally
some chlorinated phenol  content.  The
highest TCDD emissions are generally
associated with solid feed fuels and  low
combustion temperatures.   Combustion
sources burning fossil fuels tended to
emit less TCDD's than those burning waste
products.
                                            TABLE  1.
         COMBUSTION SOURCES  IDENTIFIED IN THE 1984 LITERATURE SURVEY (2)
Nupfeer of
Facilities
Source Category Tested
Minlclpal Waste Coufcustors
US*
European
Katardous Waste Tnclnerators
Incinerator Ship
Land Based Incinerators
Swage Sludge Incinerators
Utility Coal Boilers
Cofvertlal Boilers (Haste Fired)
Industrial tollers (Waste Fired)
Activated Carbon Regeneration
Residential Wood Coufcustlcn
Mobile Sources
Wire Reclavatton Incinerators
line/Cement Kilns (Waste FIrtd)
Accidental Electrical
Equipment Fires
*TCOD * Tetract>lorod1benzo-p-d1o*1n
"n««H m MH n**>

6
13

2
10(7)d
1
7
6(«id
«(Ud
1
4
9(4)"
1
Hl)d
2



Sample

Stack
Suck

Stack
Suck
Stack
Stack
Stack
Stack
Stack
Scraplnjs
Exhaust
Scrapings
Stack
Vail Sxlpr;




TCBB4
Heafi

3.5 ng/f
2S.6 ng/«3

mc
• 0.56 na/»3
f
KO
9
10.13 ng/ai3
0.013 ppt
319 ppt
4.0 ppt
234 ppt
g
; «4 port1



	 	
2,3,7.«-TCDO
Range Mean Pang*

IHM40 ng/B3 3.5 ng/n3 0.30-9,1 n^/a1
K0-tl?» ng/«3 J"

m
NO-2.5 ng/«3 NO t
t -
KO
9
HB-40.S ng/*3 13,000 ppth ND-S'i.noO ret
NO-O.OSO ppt 0.019 ppt ND-O.OB3 pp«.
MO-777 ppt 2*2 ppt 26-^00 ppt
nn-20 ppt 3.0 ppt
58-410 ppt
s -
HO-195 pp* 0.059 ppm, *



^O » Hone detected (Detection Units vary),
 furtwr of tests have been performed, but the results have not been officially reported.
  * Ont datum, no range available.
 KOO scan only.  PCM concentrations ranged fror« 483 ng/m3 to 1,140 na/n' «ith a mean of 739 ng/n'.
'Results have not ytt been officially reported.
 ppt « Carts per trillion bv weight.
 Fuels Include wood, mod/oil mixture, and natural gas.
 Fuels Include dlesel. unleaded and leaded wsollne.  In one test series, exhaust scrapings were analyzed. In the other
 lerlrs, filter nedlm fro« eihaust samples.
 loc'tides PCS transformers and cap«citor mttertes.
 ppn » parts per million by veljht.

      A  general characterization of each
of the  12  source  categories identified in
the  initial literature survey was  made to
identify similarities and differences
that  may affect the magnitude of PCOD
emissions  from each source.  The following
broad characteristics emerged.  The
source  categories with the'highest TCDD
emissions  were burning waste materials
Experimental  Studies

      In addition to gathering PCDD emis-
sions data,  all  available  experimental
studies concerning PCDD formation
mechanisms  for combustion  sources were
obtained  and reviewed  in order to identify
more  specific factors  that may contribute
to PCDD formation.
                                          252

-------
     There  are  several  unproven  hypotheses
concerning  PCDD emissions  from combustion
processes.  Dow Chemical's "Chemistries
of Fire" theory proposes that  PCDO's  are
a natural byproduct  of  fire and  will  be
formed at some  quantities  in all  combus-
tion processes  (5).   However,  experimental
results by  Buser  and Rappe (6) and  an
evaluation  of data from the literature
suggests that PCOD's are emitted only
under limited conditions.   The most
prevalent theories,  including  Esposito's
formation mechanism  (7), involve the
incomplete  combustion of PCDD's  or  PCDD
precursors.  Although there Is some
disagreement of the  definition of PCDD
precursors, they are defined in  this
paper as chlorinated aromatics that can
product PCDD's  through  bimolecular
reactions and thermal rearrangements.
Examples include chlorinated phenols  and
chlorinated benzenes.   PCDD precursors
may be thermally rearranged during
Incomplete combustion to form PCDD's.
Also, when PCDD's are present in  the  feed
to a combustion source, they can  escape
with the fine particulate  if the  destruc-
tion efficiency is low.

     Neither the Dow  hypothesis  nor the
precursor hypothesis  is conclusively
supported or refuted  by the  available
data.  Recent studies involving  pyrolysis
of wood with and without chlorination, in
conjunction with studies of  pyrolysis of
chlorinated coal, suggest  that any
organic material combusted  in the presence
of high levels of inorganic  chlorine may
lead to PCDD formation under certain
conditions.

     Based on the literature review, the
following factors are believed to affect
dioxin emissions:

       -  Waste composition
          -  PCDD In feed,
          -  Precursors in feed,
          -  Chlorine in feed,

       -  Combustion conditions
          -  Residence time,
          -  Oxygen availability,

       -  Waste characteristics
          -   Feed processing, and
          -   Supplemental  fuel
             (variability and Btu value)
The interaction of these factors in PCDD
formation mechanisms is not well under-
stood.   In addition, quantitative data
concerning waste compositions is generally
not available for many waste materials
that are combusted and combustion condi-
tions are not well defined for many
combustion devices and are largely
determined by site specific operating
practices.

Source Category Prioritization

     Despite these limitations the
factors listed above in conjunction with
available TCDD emissions data were used
to subjectively rank all combustion
sources for the purpose of the Tier 4
source tested program.   A short list of
combustion sources was  developed by
excluding those sources burning or using
a relatively clean feedstock or fired
with fossil  fuels, such as coal, oil or
gas, and those source categories which
are fairly small  or intermittent in
nature, examples  include incinerator ships
and coffee roasting.  The remaining
sources were then divided into 4 groups
ranked A-D using  the rationale outlined in
Figure 2.  The ranks  are defined as
follows:
              potential to
              •mil TCDD
          *. TCDD $*t«c**tf
          2. Pr»c«r«or l*v*t
          1. Co«tt««iloR Caudition
                                                        Figure 2.   Banking Flow Chare.
                                        253

-------
      Rank  A  are  large  source  categories
 (greater than  1  million  tons  of fuel
 and/or waste burned annually) with
 elevated dioxin  precursor contamination
 of  feed/fuel.  These categories are
 judged to  have a  high  potential to emit
 TCDO.  Rank  B are small  source  categories
 (less  than 1 million tons of  fuel and/or
 waste  burned annually) or source catego-
 ries with  limited dioxin precursor
 contamination of feed/fuel.   These
 categories have  some potential  to emit
 TCDO.  Rank  C are source categories less
 likely to  emit TCDD.   Rank 0  are source
 categories which  have  already been tested
 three .or more times.

     The ranked  list was then used as the
 focus  of the source test program.  Pre-
 liminary cost estimates  indicated that
 only 10-12 source tests  could be performed
 with the available budget.  With this
 limitation in mind, a  decision  was made
 to  test three facilities for each of the
 two rank A source categories, and a single
 facility in  each  of the  rank B  categories.
 Through supplementary  coordination with
 other  in-house programs,  samples were
 also planned for  mobile  sources  and
 woodstoves.

     Test  site selection  began  in August
 1984.  This effort was initially focused
 on  the rank A categories,  sewage sludge
 incinerators and  black liquor boilers.
 The site selection process involved
 identifying candidate sources from lists
 of  sites provided  by State and  EPA
 Regional  offices, trade  associations and
 previous EPA studies.  The lists were
 narrowed to  three or four  candidate sites
 using data on facility size, age, type of
 combustion device, etc.   Each of the
 candidate  sites on the short list was
 then contacted by  telephone to explain
 the Tier 4 program, to gather further
 site specific information, and  to ascer-
 tain if they were  interested in  partici-
 pating 1n  the program.   Pretest survey
 visits were conducted at  least  two
 candidate sites per source category.  For
 the rank A source categories, an attempt
was made to pick at least one average
 source within the source category and one
worst case candidate.   For the rank B
categories, attempts were made to select
worst case sites with respect to PCDD
emissions.
     As  the  program progressed it became
 evident  that it was very difficult to
 define the conditions which constitute
 worst case with respect to potential PCDD
 emissions.   Very little if any PCDD or
 precursor information was available for
 the  selected source categories, and the
 relative combustion conditions within the
 source category were not always known.
 For  these reasons, a great deal of
 reliance was placed upon the total
 chlorine content of the primary feed
 materials to the combustion device as an
 indication of worst case conditions.  For
 example, further information was found
 concerning the sources and levels of
 chlorides in black liquor circuits at
 Kraft pulp mills.  During the initial
 source category selection process, black
 liquor boilers associated with the
 pulping  of salt laden wood were suspected
 of having the highest chlorine content.
 After visits  to numerous mills a brief
 literature survey and receipt of chlorine
 analyses for several mills it was
 discovered that very little wood is now
 stored in salt water prior to pulping.
 In addition  black liquor with chlorine
 contents of  0.1 percent to 2 percent have
 been identified and a study was found
 which discussed the potential  for chloro-
 benzene  formation from combustion of
 black liquor  (8).  The highest chlorine
 content  black liquor was associated with
 a mill that uses spent acid from the
 chlorine dioxide generator as  a source of
 salt cake make up.

     As  the site selection process
 continued, additional  source category
 specific data became available, and as a
 result,  some changes were made to the
 ranked list.  Table 2 presents the initial
 and final ranked list.  The changes to the
 list are briefly discussed below.
 Commercial boilers  firing waste oils were
 dropped  from the rank A category because
 the proposed RCRA amendments would pre-
 clude the burning of waste oils blended
with chlorinated solvents  as other
hazardous wastes.   Combustion  of wood
 treatment plant sludges containing penta-
chlorophenol  and/or creosote (K001  waste)
 in boilers was identified as a rank B
 candidate in the initial  list.   Following
contacts  with the major wood treating
companies and with  various  regulatory
agencies, this category was dropped from
 rank B to rank C.   All  of the  wood treat-
ment companies claimed to  be either land-
 filling the  sludge  or incinerating the
sludge in a  hazardous  waste incinerator.
                                        254

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                 TABLE  2.   RANKED  SOURCE  CATEGORY LISTS  FOR PCDD TESTING
 Initial List - March  1984

 Rank A
     Sewage Sludge  Incinerators
     Black Liquor Boilers
     Commercial Boilers

 Rank B
     PCP Sludge
     Carbon Regeneration
     Charcoal Manufacture
     Wire Reclamation
Rank C
     Mobile Sources
     Wood Stoves
     Wood Fired Boilers
     Small Spreader Stoker
     Hazardous Waste Incinerators
     Lime/Cement Boilers

Rank D
Municipal Waste
Industrial Boilers Firing Hazardous Waste
  Hazardous Waste
    Current List -  March  1985
 Sewage  Sludge  Incinerators
 Black Liquor Boilers
 Carbon  Regeneration
 Wire Reclamation
 Industrial  Incinerators
 Salt-Laden  Wood Fired Boiler
 Secondary Metals Blast Furnace
 Drum &  Barrel  Furnace
Mobile  Sources
Wood Stoves
Small Spreader Stoker
Comnercial Boiler
PCP Sludge
Lime/Cement Boilers
Municipal Waste
Industrial Boilers Firing Hazardous Waste
     Charcoal manufacturing facilities
were dropped from rank B to rank C
because all facilities contacted were
processing untreated forest scraps and
not sawmill slabs that might have been
pretreated with chlorophenols for
Sapstain control.

     In addition to these changes in the
source category ranking, three categories
were added to the source test program;
these are industrial incinerators,
secondary metals blast furnaces, and drum
and barrel reclamation furnace.

     Several industrial incinerators were
identified during the course of the site
selection process.  Further investigation
showed this to be a large category in
terms of numbers of units nationwide (9).
Solid waste materials burned in these
units often contain appreciable levels of
chlorine.  In addition, most incinerators
are fairly small and batch fed resulting
in poor combustion conditions.  One site
selected for Tier 4 testing burns poly-
vinyl chloride (PVC) coated wood scraps
that have been treated with pentachlor-
phenol.  The secondary metals blast
furnace source category was also added to
the source test list.  Some blast furnaces
in the secondary metals industry process
metal bearing scrap that contains plastics
including PVC (10).  PCDD has previously
been detected in the baghouse dust from
one such facility.

     Drum and barrel reclamation furnaces
were added to the list because of the
large number of facilities, the diverse
nature of wate materials combusted
during the drum burning process and
because of the relatively poor combustion
conditions encountered (11).

The Source Test ..Program

     A total of twelve complete source
tests will be conducted as part of the
source test sampling program.  The
anticipated schedule is shown in Table 3.
In addition, one woodstove will be
sampled and two mobile source samples
will be analyzed.  The test program is
                                         255

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                                                         TABLE 3.  ma I SOURCE 7E$r SCHEDULE
complex and  involves  characterization of
combustion device  conditions using
continuous emissions  monitors in addition
to Modified  Method 5  sampling for PCDD's
following the  draft ASME protocol (12),
Samples of the feed materials to the
combustion device  will  be sampled and
analyzed for chlorine and precursor
content.  Ash  and  soil  samples will be
collected and  analyzed  for PCDD's.  The
sample matrices for the first 5 tests
are shown in Table 4.

     All testing is expected to be
completed by July  1,  1985.   Only
limited PCDD analytical results are
available at this  time.  All  results
will be presented  in  the final Tier 4
report which is scheduled for completion
fn late 1985.   Results  of the study will
also be Included in a report to Congress
scheduled for  December  1985.

Ash Sampling

     A total of 40 ash  samples will be
collected for  combustion sources selected
by EPA regional  offices.  Analysis of
these samples  will  supplement the source
test data.
rest
Hyaber
1
2
3
4
5
6

7
6
9
10
11
u
Scnemile
flctaaer 1984
"oveoiMr 19B«
H
-------
1.   National  Dioxin Study Tier 4 -
     Combustion Sources;  Project Plan.
     EPA-450/4-84-Q14a, Monitoring and
     Data Analysis Dioxin.  U.S.
     Environmental Protection Agency,
     Research  Triangle Park, N.C.
     February  1985.

2.   National  Dioxin Study Tier 4 -
     Combustion Sources:  Initial Litera-
     ture Review and Testing Options,
     EPA-45Q/4-84-014b.  U.S. Environ-
     mental  Protection Agency.  Research
     Triangle  Park, N.C.

3.   National  Dioxin Study Tier 4 -
     Combustion Sources:  Sampling
     Procedures.  EPA-45Q/4-84-014c.
     U.S.  Environmental Protection
     Agency.   Research Triangle Park,  N.C.

4,   National  Dioxin Study Tier 4 -
     Combustion Sources:  Ash Sampling
     Program.  EPA-450/4-84-014d.  U.S.
     Environmental Protection Agency.
     Research  Triangle Park, N.C.

5.   Dow Chemical.  The Trace Chemistries
     of Fire - A Source of and Routes  for
     the Entry of Chlorinated Dioxins
     into the  Environment.  Dow Chemical
     U.S.A., 1978.  46 pp.

6,   Buser, H. R. and C. Rappe.  Formation
     of Poiychlorinated Dibenzofurans
     (PCDFs) from the Pyrolysis of
     Individual PCB Isomers.  Chemosphere,
     1(3):157-174, 1979.

7.   Esposito, H. P., T. 0.  Tiernan and
     F.  E. Dryden.  Dioxins:  Volume 1:
     Sources,  Exposure, Transport, and
     Control.  EPA-600/2-8Q-156,
     U.S.  Environmental Protection
     Agency, Cincinnati, Ohio, June 1980.

8.   Ahling, 8. and A. Lindskog.  Emission
     of Chlorinated Organic  Substances
     from Combustion.  In;  Pergamon
     Series on Environmental Science,
     Volume 5, 1982.  pp. 21S-225.

9.   Source Category Survey  - Industrial
     Incinerators.  EPA-450/3-80-13.
     U.S.  Environmental Protection
     Agency.   Research Triangle Park,
     N.C.  May 1980.
 10.  Pretest survey report to U.S. Metals
      Facility,  Cateret, N.J.
 11.  TonhUl.'C. J.  "Barrel and Drum
      Reconditioning Industry Status
      Profile."  Tonhill, Shuckrow, and
      Associates.  EPA Contract
      No.  68-03-2905.  1980.

 12.  Draft ASME Sampling Protocol
      "Sampling  for the Determinations
      of Chlorinated Organic Compounds
      in Stack Emissions".  October 1984.
                  Disclaimer

This  paper has been reviewed  in
accordance with the U.S.  Environ-
mental  Protection  Agency  peer and
administrative review policies and
approved for presentation and publi-
cation.
                                       257

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   THERMAL CLEANING OF SOIL CONTAMINATED WITH CYANIDE WASTES FROM

                       FORMER COAL GASIFICATION PLANTS


          Ed W.B. de Leer, Marian Baas, Corrie Erkelens, Daan  A. Hoogwater,
                       Jan W. de Leeuw, and P.J.Wijnand Schuyl

         Delft University of Technology, Department of Chemical Technology,
                     Jaffalaan 9, 2628 BX Delft, The Netherlands

                                 Laurens C. de Leur

         B.V.  Aannemingsbedrijf NBM, P.O. Box  16032, 2500 BA 's Gravenhage

                                    3an W.  Graat

                  Smit Ovens B.V., P.O. Box 68, 6500 AB Nijmegen



                                    ABSTRACT

   The thermal cleaning of polluted soils from coal  gasification plant sites was studied,
both in laboratory experiments  and in a 500 kg/hr  pilot  plant. The  soils investigated
were  contaminated  with a  mixture  of iron cyanide  complexes  (e.g.  Prussian  Blue
Fe«,[Fe(CN)6]3)  and  polynuclear  aromatic   hydrocarbons  (PAH's)  in concentrations
ranging from 1-2.5 g CN/kg and 30-180 mg PAH/kg, respectively.
   To  decompose the  cyanide complexes, temperatures of 300-350  °C and a residence
time of 30 min are necessary. Residual  cyanide concentrations  then vary  from 3 to 17
mg/kg. Under these conditions, PAH's are removed as  well, with residual concentrations
below  the  detection  limit of 0.01 mg/kg. The cyanide complexes decompose into a
mixture of  hydrogen  cyanide (HCN)  and cyanogen ((CN)2), both  gaseous compounds
which can be incinerated.
   These conditions  were shown  to be valid  too for  the  pilot  plant.  At  an  oven wall
temperature of 440  °C (soil  temperature ca. 350  °C),  soils contaminated with 40-130
ppm cyanide were cleaned to a residual level of 1-4 ppm.
   A study on a laboratory scale of the incineration of  HCN showed that  temperatures
of ca.  1100 °C are sufficient for >  99% combustion  at contact times of  0.4-2 sec. A
marked influence of the oxygen concentration on the  incineration  yield  was observed.
Increasing  the  Oz  concentration from  3.1  to  13.5  %,  decreased  the  temperature
necessary  for incineration with about  100 °C.
   The pilot plant incinerator was shown to be  more than  99.9  % effective at  1050  °C
with HCN concentrations in the off-gas of 0-2.5 ug/m3.
                                        258

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  INTRODUCTION AND PURPOSE

    In the past, town gas was prepared in The
  Netherlands by  gasification of  coal  to
  produce a  mixture  of mainly  methane,
  carbon  monoxide  and  hydrogen (CH,,  CO,
  HZ).  This. gas mixture  was  purified by
  removal  of  inorganic  compounds  like hy-
  drogen cyanide  (HCN) and sulfide  (HaS) and
  organic compounds like polynuclear  aromatic
  hydrocarbons (PAH) and  phenols.
  For  the  removal  of  HCN  so  called  "iron
  boxes" were  used, in which the cyanide was
  bound  as iron complexes like  Prussian  Blue
  Fe.»[Fe(CN)g] 3.  In fact a  very  complex
  mixture  of  iron   cyanides and  sulfides
  resulted,  which was stored before further
  processing or  (un)intentionally dumped  on
  the terrain.

Now that  town gas  plants are no  longer in
operation,  severe  soil pollution  problems
remain.   Concentrations of cyanide in  the
form of complex cyanides of up to 20  g/kg
can be  found  in The Netherlands,   mostly
in combination  with  alarming amounts of
PAH's,  phenols and sulfur compounds.
Thermal  cleaning   of these  soils  seems
promising as   it may  be expected that at
high  temperatures the  organic compounds
are volatilized and the  cyanides decom-
pose to form  iron  oxide  and gaseous cya-
nide compounds.    Incineration of the  de-
composition   products  may  complete  the
cleaning  process.
 Several systems  have been developed to heat
 the contaminated  soil. In direct  heating
 systems,  the  soil is  heated  by burners in  a
 rotating  tube oven  or  a  fluidised  bed oven.
 Large  amounts of  burning  gasses   are
 produced which  must be processed together
 with the volatilisation and  decomposition
 products.
 We  investigated  and  developed  an  indirect
 heating system  in  which  a  rotating tube
 oven  is  heated  externally by  a  series of
 burners.  The  burning gasses  are  not mixed
 with  the  gaseous decomposition and  volati-
 lisation products of  the soil,  which  gives an
 advantage in  the design  of  the  incinerator,
 where  we  now  have  to process  the   de-
 composition products from the soil only.
 The gas flow in the tube oven is  reduced,
 which  causes less  dust material  to  be
 transported to the cyclone and  the incine-
 rator.
 Finally,  the oven  temperature  is better
 controlled which  is a distinct  advantage in
 the case of  the  treatment of  soils  conta-
 minated with organochlorine compounds.

 APPROACH

 Characterization of  Cyanide Soils

    Three types of cyanide soils, originating
 from different locations  in  the  Netherlands
 were used  in this  investigation.  The soils
 were characterized  by quantitative analysis
 of  the  "free"  and "total" cyanide, and  the
 PAH's.  For general  characterization the  pH
 and the total  residue on  drying at  105  °C
 were determined. The three  soils will  be
 designated as A, B and C.
 Whenever  concentrations  are  given  in  this
 paper,  concentrations on  dry  weight  basis
 are meant.

 Total cyanide determination.

    Samples of 5-10  g of  polluted  soil  were
 suspended in 100 ml  of distilled water. After
 addition of 15 ml of  concentrated  HC1,  10
 ml  of 0.8 M CuSO,  solution, 2  ml of  1.8 M
 SnClz solution in 0.5 M HC1, and 1 ml of a
 1  %  CdSOi,  solution, the  suspension was
 refluxed for 90 min. The  HCN  formed, was
 collected  in  50  ml  of   1.25  M  NaOH  by
 passing  a gentle stream of nitrogen through
 the suspension.
 The final  alkaline  cyanide  solution  was used
 for the cyanide determination  according  to
 Standard Methods  and  EPA procedures (1,2).

 Free cyanide determination.

   Free  cyanide was  determined as  described
 above, but with the  omission of  the CuSO»
 solution, which is  the catalyst for the de-
 composition of the complex cyanides.

 Determination of  polynuclear  aromatic
 hydrocarbons.

     Basically  the  procedure  according  to
Giger and Schaffner (3) was followed,  with
some  modifications  which  were  necessary
due to the nature of  the samples.
 A  sample of 6-10 g (wet weight) was ex-
 tracted  by sonication  with CH2C12/CH3OH.
 After addition  of  water  the CH2Cl2  layer
was isolated and concentrated  to a volume
of 5-10  ml.
                                       259

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       Elemental  sulfur  was  removed by  elution
       over  a  copper  column.  The  extract  was
       further  purified  by  chromatography  on
       subsequently,  Sephadex LH-20 with benzene-
       methanol, silicagel  with pentane-dichloro-
       methane, and  silicagel  with  toluene. After
       the final concentration to  0.5 ml, the PAH's
       were determined  by capillary  GC  with on
       column injection and FID detection.
       Instrument: Carlo Erba  *160; Column:  fused
       silica coated  with SE-52  (d=0.32 mm;  1=20
       m); Carrier gas: helium (p=0.5 bar);  Injector
       temperature:  80 °C; Oven temperature:  130
       °C,  programmed to 330 °C  with it  °C/min.
       Quantitation was carried out using a  solution
       of  anthracene  in  toluene as  an  external
       standard. GC/MS analyses were performed
       to confirm the identity of  the PAH's.

       Thermal Cleaning - Laboratory  Experiments

          Carefully weighed samples of  5-50 g were
       heated  in  a quartz tube  in an electrically
       heated tube  oven. The temperature,  the
       residence time  of the sample in the heated
       zone, and the composition  of the atmosphere
       (air or nitrogen) were  varied, and their
influence  on  the residual  amount  of  total
cyanide in the soil was  measured. To obtain
a cyanide balance,  the  gaseous decomposi-
tion  products  were  collected  by adsorption
in a  1.25 M  NaOH  solution. This  solution
was used for  a quantitative cyanide  analysis
after  completion of the  experiment.
All experiments were performed in duplicate
or triplicate.

Thermal  Cleaning - Pilot  Plant  Experiments

  Figure  1 gives a schematic drawing of the
pilot plant used  for the thermal cleaning of
soils.  The polluted  soil  is  supplied to  the
rotating  tube oven  through  a gas  tight
locking  device. The tube  oven is set at  an
inclination of 1.5  °C  and  is rotated  at a
speed  of  4  rpm.  The  maximum   input  of
polluted soil  with a moisture  content of  15
% is  500 kg/hr. Three  oil or  gas  burners
heat the tube oven to a maximum tempera-
ture  of 850  °C. The  gaseous decomposition
products pass through a cyclone to remove
dust   and  are  then  fed  to  an incinerator
(temp. max. 1350 °C).
                                        -.-—
                          GAS/OIL                     COOLING  WATER
                                      CLEANED SOIL
Figure  1.  NBM  pilot  plant for  the  thermal  cleaning  of  soils  by  indirect  heating.
                                                260

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                                                                        TWOWAY VALVE
                                                                                NITROGEN PHOSPHOROUS
                                                                                SELECTIVE DETECTOR
   Figure 2. Laboratory installation for  testing  the incineration of  HCN.
The  cleaned  soil  leaves the  tube oven
through a gas tight locking  device,  is then
cooled  and moistened by  spraying with
water, and  removed for storage.
The tube oven, together with the input  and
output  locking devices, are flushed with
inert gas (CO2 +•  N2)  to prevent explosions.
The results of the study on the  influence of
the temperature  of the tube oven  and  the
incinerator on  the residual amounts  of
cyanide on the soil and in the  off-gas  will
be presented here.

Incineration of HCN  - Laboratory  Experi-
ments
                                        stream through  a  nitrogen-phosphorous
                                        selective   detector  (NPD)  used  in  gas
                                        chromatography. This  NPD  shows  a good
                                        linear  response (5 decades) together  with a
                                        high sensitivity  (1QE-14  g  N/sec).  In our
                                        experimental  set  up,  the minimum  detec-
                                        table amount of HCN in  the gas phase was
                                        3-2*10E-3  ppm.

                                        RESULTS

                                        All three  soils used had  a sandy character
                                        and a  low water content.  The  pH of soil B
                                        had  a  very  low  value,  maybe  due  to
                                        microbiological conversion of  sulfide  to
                                        sulfuric acid. The  results of the  general
                                        characterization are given in Table  1.
                                           First the influence of the temperature  on
                                        the decomposition of  the  complex cyanides
                                        was studied.  After heating for  1  hr  at the
                                        given  temperatures, the residual amount  of
                                        cyanide in the soil was determined, together
                                        with the total amount of volatilised cyanides
                                        adsorbed in the NaOH solution. The  results
                                        for soil C are given in Figure 3.

Table  1.  Analytical results  for  the  soil samples  used in the
            thermal cleaning experiments.
   The incineration of HCN was studied in a
quartz tube oven (Fig. 2) at temperatures of
800-1250 °C, residence times  of QA-3A sec,
and different oxygen concentrations. The
concentration  of  HCN  was measured  by
passing  the   gas  stream  through  a  NaOH
solution followed by  a colorimetric cyanide
analysis or,   directly  by  passing  the gas
Soil Sample
A
B
C
% dry weight
91
92
88
pH
7-5
1-3
6.9
Free CN
(g/kg)
0-33
0.5M
0.5M
Total CN
(g/kg)
1.29
2.23
1.85
Total PAH
(mg/kg)
128
176
27
                                       261

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                         300       500
                        •- Temperature! °C)
Figure 3.
Total amount  of cyanide  in the soil and the
gas  phase  after  heating  soil  C  for   1  hr.
     The influence of the residence time  in
  the heated zone was studied with soil C   at
  300  °C. The results are given  in  Table  2,

    A temperature of 300 °C and a contact
  time  of  30  min was   used to  study  the
  decomposition of the complex  cyanides  in
  the other soils. The results  are presented  in
  Table 3.
 The  results for  the  PAH analyses  in the
 original  samples and  in sample A after
 heating for 30 min. at 300 °C and 500 °C are
 presented in Table *. Heating of samples  B
 and C gave identical results as for  sample
 A.

 Measurements  performed during  a  4  days
 experiment  in the  NBM pilot  plant  gave
 similar results. The wall  temperature of the
 rotating  tube oven  was varied between
 *OQ°C and  650°C (soil temperature  at exit
 approximately  100 °C below  wall  tempera-
 ture) with a load of 500  kg/hr. The soil was
 sampled at the entrance  and  the exit of the
 oven and analysed  for total  cyanide (Table
 3).

 Cyanide  concentrations  were also  deter-
 mined in  the dust formed during  the  heating
 process, which is collected in the cyclone (±
 1%  of the  input). With a wall temperature
 of 550-650°C the cyanide  concentration
 varied between 10-32  mg/kg, whereas .at  a
 wall temperature of 400 C the concen-
 tration varied between 98-755 mg/kg.

 The results for the incineration of the  HCN
containing gas are  not given in  full  detail,
but  exemplified with the decomposition  of
HCN in the laboratory experiments. Figure  *
gives the  residual HCN concentration in the
off-gas at different oven temperatures and
flow rates. The  initial HCN  concentration
was 326  ppm (0°C, 1 bar).  The  flow  rate
was kept  constant while the temperature  of
the  oven  was  varied between  750-1250°C.
      Table 2. Influence of the contact  time at  300
                 of the complex  cyanides in soil C.
          C  on  the  decomposition
Time (rain)
Residual CN
in soil
(g/kg)
0
1.85
0.
10
013
0.
20
022
0.
30
017
0
60
,014
      Table  3-  The decomposition  of complex  cyanides on three  soils  at
                 300  °C and  a contact time  of  30  min.
Soil
CN in gas phase (g/kg)
Residual CN in soil (g/kg)
Total CN after heating (g/kg)
Total CN before heating (g/kg)
A
0.56
0.013
0.57
1 .29
B
1.17
0.003
1.17
2.23
C
0.88
0.017
0-90
1.85
                                                262

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Table H.
Type of PAH
Phenanthrene
Anthracene
Fluoranthene
Pyrene
Benz [a Janthracene
Chrysene
Benzofluoranthene isomer
Benzofluoranthene isomer
Benzo[a]pyrene
Benzo [e ]pyrene
Perylene
Total PAH
Depending on the flow rate

A
8
1
22
21
9
12
26
2
12
13
i|
128
and the

B
1.2
<0.5
5.3
<0.01
•2.3
3-7
4.9
<0.5
2.11
2.1
0.5
27-il

C
14
2
33
5-0
11
15
32 -
4
16
17
5
176

A300
<0.01
<0.01
<0.01
<0.01
<0.01
<0 . 01
<0.01
<0.01
<0.01
<0.01
<0.01
N.D.

A500
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
N.D.
DISCUSSION
             temperature,  the  contact  time  varied
             between  2.5 sec {30 ml/min at 800°C) and
             0.4 sec (116 ml/min  at 1200°C).

             The influence of the  oxygen concentration
             on  the incineration of HCN is given in Fig.5.

             In  the pilot  plant experiments  incineration
             temperatures of 1100-12000C were used.
             With a contact time of 0.5 sec, no cyanide
             could  be  detected in  the  flue  gasses
             (detection limit 6 ug/m3).
                                                     The results presented in  Fig.3 and Table 3
                                                     and 4 show that the indirect heating of soils
                                                     contaminated  with complex  cyanides  and
                                                     PAH's is a very effective cleaning process.
                                                     The percentage of cyanide  removal  after
                                                     heating for 30  min at 300 °C was 99.0, 99.9
                                                     and 99.1% respectively for  the  three types
                                                     of soil used. PAH's were also removed under
                                                     these  conditions  as  their  concentration
                                                     decreased  to below the detection limit (0.01
                                                     mg/kg).
          j i i • i : i * • « i i s'i : i * ' ; i i 4
Fl8ure
                                                     Figure 5.
Influence  of  the  flow  rate  on  the  decom-  Influence  of  the  O2-concentration  on   the
position  of  HCN at different  temperatures,  decomposition  of HCN at  different tempera-
                                                     tures.  Contact  time:  0.5  sec  at  1000°C.
                                                  263

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      100

 X|CN|2
       so
                A large deficit in  the  cyanide  balance is
                remarkable  in  these experiments (Fig. 3,
                Table  3). At 300°C only  about  50%  of  the
                original cyanide was recovered from the  gas
                phase. As the recovery  of cyanide  from  the
                gas phase was shown to be quantitative  and
                no  cyanide  remained  in  the  soil,  some
                unidentified chemical conversion  of cyanide
                must occur.

                Several assumptions can be made:
                a).  The  complex  cyanides  decompose  into
                HCN,  followed by oxidation of  HCN  to
                (CN)2  or  CO2(  or  by hydrolysis to  formic
                acid
1: MHCN +  02  * 2(CN)2
2: WON + 502  -* *IC02
3:  HCN -i- 2H20 +  HCOOH
2H20
2N2
 NH3
                                                 2H20
               b).  The complex cyanides decompose  into
               cyanogen (CN)2.

               Oxidation reactions  can be excluded as  they
               start only at  about  800  °C  and the  same
               cyanide deficit  was  found when the  reac-
               tions were performed in an insert (Nj) gas
               atmosphere.  For the  gas phase hydrolysis of
               HCN an increased conversion with increasing
               temperature  should  be  expected, which was
               not observed.
                100
                                30O              500

                                   • Temperature {'
 Cyanogen formation may explain the cyanide
 deficit  as (CN)z  reacts with NaOH to  give
 cyanide  and  cyanate, so  only  50% of  the

 (CN)2 +  2OH" •* CM" + CNO" + H2O

 original  cyanide  is recovered in  the  analy-
 tical procedure. Assuming that the complex
 cyanides decompose into HCN  or (CN)2 the
 percentage of (CN)2 in the gas  phase can be
 calculated (Fig. 6).

 Apparently,  100% of (CN)2  is formed below
 300 °C, while  at higher temperatures
 mixtures of HCN and (CN)2  must be formed.
 Possibly, the  (CN)2 reacts  with   hydrogen
 donors like  H2S  or H2O  at high   tempera-
 tures to  form  HCN. The cyanogen hypothesis
 was confirmed   in  one  experiment  by
 hydrolysing   the  cyanate  to  ammonia.
 Determination of the ammonia  content gave
 the missing cyanide.

 As  expected  from  the  laboratory  experi-
 ments  the indirect thermal  treatment of
 cyanide soils  presented  no special  problems
 in the pilot plant experiments.  Above WOflC
 no  significant  influence of the temperature
 on the  residual cyanide concentrations in the
 soil was  detected. At a  wall temperature of
 MO °C  the residual cyanide  concentration
 was 4.0  +_  1.3   mg/kg,   but this  value
 increased rapidly  to 22  mg/kg  when  the
 temperature of the soil at  the exit of the
 tube oven decreased to 225 °C.

 The cyanide  concentrations  in  the  dust
 formed during  the heating  process   also
 increased considerably  at  temperatures
below WO °C,  indicating that  the  tempera-
 ture was to  low for complete conversion of
 the complex cyanides.

 Incineration  of HCN presented no special
problems, both in  the  laboratory  and  the
pilot plant experiments.  A  temperature of
 1000-12000C  is  sufficient  for   > 99.5%
conversion. A high  oxygen  content in  the
 incinerator  gas  is  important  as  this   may
lower the incineration temperature  necessa-
ry for  > 99.5% conversion with ca. 100°C.
Figure  6.
%i  (CM) 2  in the  gas  phase  after  heating  of
sample C.
                                                  264

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Table 5.  Total  cyanide in  soil  from  a coal gasification  plant  before and
           after  thermal treatment in  a 500  kg/hr pilot plant. The average
           concentration (x),  the standard deviation  (s.d.)  and  number of
           determinations  (n)  are given for  the  input  and  output.
      Wall  temp.
Total CN  concentration in soil  (rag/kg)
  Input                      Output
x     s.d.      n             x     s.d.     n
400
550
650
650
44
64
126
48
4
21
77
8
8
8
8
9
4.0
1.6
3-1
2.5
1.3
0.4
0.1
0.5
4
9
9
7
   CONCLUSIONS '

   It was shown that soils,  contaminated with
   complex  cyanides and PAH's can be cleaned
   very efficiently  by  indirect heating in  an
   inert gas atmosphere.
   Pilot plant experiments on a 500 kg/hr scale
   have indicated that residual cyanide concen-
   trations of ca. 2 mg/kg can be attained at a
   wail temperature of the  rotating tube oven
   above 400°C.
   Incineration  of the HCN  and (CN)2 formed
   presents  no  special  problems  at  tempera-
   tures above  1000°C.
   The scaling-up of the present installation to
   a 20.000 kg/hr plant is under investigation.

   ACKNOWLEDGEMENTS

   The information in this report  has  resulted
   from research funded in  part by the Dutch
   Ministery of  Environmental Affairs.

   REFERENCES

   1.
   American Public Health  Association,  1980.
   Standard Methods  for Examination of Water
   and Wastewater. Method 412 D, p 320.

   2.
   Methods  for  Chemical Analysis of Water and
   Wastes, 1979.
   EPA-6QO/4-79-Q2Q,  USEPA Environmental
   Monitoring  and Support  Laboratory, Cin-
   cinnati, OH, Method  335.2.

   3.
   Giger W., and Schaffner  C., 1978, Determi-
   nation of Polycydic  Aromatic Hydrocarbons
   in  the Environment  by Glass Capillary Gas
   Chromatography, Analytical Chemistry, Vol.
   50,  p 243-249.
                            Disclaimer

            The work described in  this  paper was
            not funded by the U.S. Environmental
            Protection Agency.  The contents do
            not necessarily  reflect the views of
            the Agency and no official  endorse-
            ment  should be inferred.
                                         265

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                  CLAY LINERS: WHERE DO WE 60 FROM HERE?
                              David E, Daniel
                          The University of Texas
                             Austin, TX  78712

                                 ABSTRACT

       The use of clay liners as the sole liner for hazardous waste impound-
ments and landfills has declined substantially in the last several years.
Questions have been raised about the effectiveness of clay liners and about
the degradation of clay liners that are exposed to chemical wastes.

       Clay liners do have an important place in land disposal technology,
but many improvements are needed in design and construction technologies.
More data are needed to confirm field performance.  Monitoring of underlying
aquifers is useful for determining whether major leaks have occurred but
is of limited use in demonstrating that clay liners are performing effec-
tively.  Until earth scientists and engineers build a data base that demon-
strates that clay liners are performing well, doubts about the effective-
ness of clay liners will persist.
INTRODUCTION

       Earth liners have been used
worldwide for several decades to re-
tard the movement of pollutant-laden
liquids into the ground.  Earth liners
may be constructed from naturally-
occurring clay soils or from mixtures
of soil with bentonite.  Such liners
are often referred to as "clay liners"
even though the earth liner is com-
posed of less than 50% clay because
the clay fraction controls the hy-
draulic properties of the liner.

       Up until the late 1970's and
early 1980's, the consensus among
ground-water specialists seemed to
be that clay liners were working
fairly well.  However, beginning in
the early 1980's, a number of revel-
ations raised questions about the
effectiveness of clay liners.  In
1981, Brown and Anderson reported
findings from EPA-sponsored research
which showed that under laboratory
conditions concentrated organic
chemicals attack compacted clay and
increase the permeability of com-
pacted clay by several orders of
magnitude.  The organic chemicals
rendered the clay essentially use-
less as a barrier to pollutant mi-
gration.  Additional field work on
prototype clay liners verified the
earlier laboratory findings  (Brown,
Green, & Thomas, 1984).

       The reputation of clay liners
was further diminished when  Daniel
(1984) published an analysis of se-
veral case histories  in which the
                                    266

-------
actual permeability of full-sized
clay  liners for water retention
structures was determined from data
on  field performance.  The liners
were  remarkably permeable despite the
fact  that laboratory permeability
tests had indicated very low permea-
bilities.  Because evaluations of
nearly all existing clay liners for
hazardous waste disposal facilities
are based on  results of laboratory
permeability  tests, it is possible
that  many more clay liners are leak-
ing at rates  far  exceeding expecta-
tions.

       Shortly after these and other
findings were made public, the U.S.
EPA changed it regulations in a man-
ner that discouraged the use of clay
liners for hazardous waste landfills.
The initial set of regulations ef-
fectively banned  the use of clay
liners for hazardous waste land-
fills arid impoundments.  The cur-
rent  draft EPA regulations permit
the use of clay liners, but only in
a backup role to  flexible membrane
liners.  In effect, these regula-
tions reflect a low degree of confi-
dence that clay liners can by them-
selves be effective in preventing
the subsurface migration of pollu-
tants from waste  disposal facilities.

       These facts raise questions
about the future  of clay liners.
Will  there be a continued decline in
the use of clay liners and perhaps
an  eventual phasing out of clay lin-
ers altogether, or is it premature
to  assume that clay liners will be
replaced by other technologies?  The
purpose of this paper is to exam-
 ine the future of clay liners.  In-
deed, if clay liners do have a fu-
ture, what needs  to be done to sol-
 idify their place in the array of
available containment technologies?

CAN CLAY LINERS BE EFFECTIVE?
Effectiveness as a Hydraulic Barrier

      It would seem that one ought to
be able to construct a clay liner that
is reasonably effective in virtually
stopping migration of liquids through
the liner.  After all, under labora-
tory conditions it is not particu-
larly difficult to construct compacted
clay liners that are almost imper-
meable to water.  Typically, proper-
ly constructed compacted clays have
permeabilities in the laboratory.in
the range of 1 x 10"B to 1 x 10"L
cm/sec (Lambe, 1954; Mitchell et  a!.,
1965; and Boynton and Daniel, 1985).
With this range of permeability, a
unit hydraulic gradient, and an ef-
fective porosity of 0.2, the velocity
of water movement through a clay
liner would range from 0.16 mm/yr to
16 mm/yr.  Such rates of movement
are so slow that molecular diffusion
is probably a more important mechan-
ism of pollutant transport than ad-
vective transport (Gillham et al.,
1984).

      Other mechanisms may tend to
slow the rate of pollutant transport
even more.  For example, ion ex-
change, adsorption, precipitation,
oxidation/reduction reactions, and
biological degradation all serve to
retarct pollutant transport through
earth materials.

      The types of calculations and
assessments presented in the pre-
vious two paragraphs are not new.
These facts have been known for sev-
eral decades and have formed the
basis for a high degree of confi-
dence among earth scientists and en-
gineers that clay soil materials
would indeed be effective in re-
tarding the flow of both water and
pollutants through such materials.
Numerous laboratory experiments
have served to confirm that rates of
flow indeed can be quite small.
                                    267

-------
      While it is clear that practi-
cally impermeable clay liners can be
constructed in the laboratory, it is
not clear that equally effective
barriers can be constructed in the
field.  For examples Day and Daniel
(1985) describe two prototype clay
liners that were constructed in the
field on EPA-sponsored research.
The actual permeabilities of the
liners were determined by ponding
water on the liners for several
weeks and measuring the rate of seep-
age.  The permeabilities turned out
to be only slightly less than 1 x
10-  cm/sec despite the fact that
laboratory measurements yielded per-
meabilities of 1 x 10"° cm/sec or
less.  Day and Daniel concluded that
hydraulic defects were present in
the field that were absent from lab-
oratory test specimens.

      While it would seem that clay
liners can be extremely effective as
hydraulic barriers, there is no de-
finitive base of field performance
records to prove that clay liners
are effective.  The only reasonably
well-documented cases of successful
performance of clay liners were re-
cently reported by Gordon et al.
(1984).  The cases involved 5-ft-
thick clay liners beneath municipal
waste landfills.  Unsaturated zone
monitoring beneath the liners show-
ed  that contaminants had not mi-
grated significant distances in 5
to 10 years of operation.

      Until more data of this type
are developed, doubts about the
effectiveness of clay liners are
likely to persist.  In addition, it
is not clear that the hydraulic in-
tegrity of earth liners will be
maintained during prolonged expo-
sure to a myriad of concentrated
chemical wastes.

Attack by Chemical Wastes
      A number of studies have been
conducted in the laboratory to eval-
uate the effects of chemical  wastes
upon earth materials.  The tests
show that concentrated acids  can
dissolve earth materials and  lead
to increases in permeability; how-
ever, earth materials have a  large
buffering capacity, and it may take
large quantities of acid to produce
sufficient dissolution of earth
materials to yield a significant in-
crease in permeability (Nasiatka et
al., 1981; and Peterson et al.,
1985).

      Concentrated organic chemicals
have been shown to cause large in-
creases in the permeability of com-
pacted clay even with small quanti-
ties of flow (Brown and Anderson,
1983; Brown, Green, and Thomas, 1983;
Brown, Thomas and Green, 1984; and
Foreman and Daniel, 1984). The data
plotted in Fig. 1 are typical.  Or-
ganic chemicals tend to flocculate
clays and to cause other structural
alterations, such as cracking, that
lead to an increase in permeability.
However, additional laboratory in-
vestigations have shown that  effects
of a particular chemical upon the
permeability of a particular  soil
are strongly dependent upon the
method of laboratory testing.  Up
to two orders of magnitude of dif-
ference in permeability have  been
observed between permeabilities
measured in different types of per-
meaitieters on the same soils using
concentrated organic chemicals
(Hamidon, 1984).  The overburden
pressure applied to a clay also
affects the susceptability of the
clay to attack by concencentrated
organic chemicals (Fig. 2) in lab-
oratory experiments.  Even the
details of soil compaction can have
a major effect on test results.
In unpublished work at the Univer-
sity of Texas, identical soils were
                                   268

-------
               o>  Wo ten Methonol
                 10   0     I    2    3
                   PORE VOLUMES OF FLOW
 Fig.  1   Permeability of Compacted Clay to Water and
          Methanol. (after  Brown & Anderson, 1983)
             10
                Vtrficul Effacflv* Sim* CkPa)
              ..0  20  40  60  80  100 120
             10
              ,-6
             10
              -8
             10  0     5    10    15    20
            Equivalent Depth of Soil Ovtrburdtn (ft)
Fig. 2   Effect of Overburdern Pressure on the Permeability
         of Compacted Clay that is  Permeated with  Methanol
         (Daniel, 1985}
                            269

-------
compacted with two different ASTM
compaction procedures (ASTM D-698
and D-1557) and then the soils were
permeated with heptane.  After 1
month of permeation, the permeabil-
ities differed by a factor of more
than 1 million.  Thus, the effects
of concentrated organic chemicals on
clay materials depend very much on
the details of testing.  Because
none of the laboratory testing tech-
niques presently available exactly
duplicates field conditions, one
cannot be certain that the labor-
atory findings can be applied direct-
ly to field problems.  Until this
question is resolved, the effects
of concentrated organic chemicals on
the integrity of clay liners will
remain a controversial issue.

      Dilute organic chemicals do
not seem to attack clay or to cause
significant increases in permeabil-
ity (Brown et a!., 1984; and Daniel
and Liljestrand, 1984).  The data     2.
cited above show that certain chem-
icals can attack earth liner mater-
ials whereas other chemicals pre-
sent no problem.  If clay liners are
to have a future, greater efforts
are needed to minimize the possibil-
ity that clay liners will come into
contact with liquids that could de-
grade the chemical and structural
integrity of the clay liner.

HOW SHOULD CLAY LINERS BE DESIGNED
AND CONSTRUCTED?

      It is this writer's opinion
that new directions are needed in
the procedures used to design and
construct clay"liners if effective    3.
liners are to be achieved.  The
following recommendations provide
a foundation:

1.  Current design practice relies
    on the use of laboratory permea-
bility tests as an indicator of
probable performance of a clay
liner.  The studies discussed
earlier suggest that laboratory
permeability tests can yield
misleading values of permeabil-
ity.  It would be best, as part
of the design phase, to con-
struct a field test section us-
ing actual liner materials, full-
sized construction equipment, and
the actual construction pro-
cedures that are contemplated for
the clay liner.  Extensive test-
ing could be done on the field
test section to establish the
actual permeability of the field-
constructed clay and to evaluate
other pertinent parameters.
Such field data would provide far
greater assurance that the clay
liner will perform as intended
than presently exists with cur-
rent design methodologies.

The primary use of laboratory
permeability tests should be to
study the effects of chemicals
upon the integrity of the clay
liner.  Use of field tests with
water, supplemented by labora-
atory tests with chemicals, is
the recommended approach.  Be-
cause different types of labora-
tory permeability tests provide
radically different results in
some instances, more than one
type of test may be needed.  In
addition, other types of tests
besides just permeability tests
should be performed (Bowders
et a!., 1985).

Construction practices for com-
pacted clay liners have sometimes
been inadequate.  The presence of
clods of clay may be very de-
trimental to clay liner  perfor-
mance (Daniel, 1984) so clods
should be pulverized or otherwise
                                     270

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4.
broken down prior to compaction
of clay.  The water content of
the clay at the time of com-
paction is also important, but
little attention is presently
given to allowing time for the
proper hydration of clay clods
after water has been added to
clay, but before the clay is
compacted.  Techniques for eli-
minating desiccation cracking
during and after construction
need to be developed.  It may
be necessary to cover the
compacted surface immediately
after construction, even if
only temporarily.  Construction
techniques that lead to proper
remolding and elimination of
hydraulic defects during con-
struction have received only
superficial study so far.  With
greater recognition of the po-
tential problems in achieving
a clay liner with low permea-
bility, and with greater atten-
tion to details of construction,
it should be possible to achieve
a much better product than is
often seen today.

In laboratory tests, increasing
the overburden pressure on clay
reduces the susceptibility of
clay to attack by chemicals
(Fig. 2) and helps to close any
cracks (Boynton and Daniel,
1985).  The overburden pressure
can be increased on the clay
liner by increasing the thick-
ness the thickness of the clay,
placing solid material over the
clay (such as loosely placed
earth) that provides weight, or
by placing solid waste over the
clay in a way that spreads the
load from the waste uniformly
over the clay.  At present,
little consideration is given to
the overburden pressure acting
on a clay liner.
5.  At present, too.much emphasis is
    placed upon the permeability of
    a clay liner and too little em-
    phasis is placed upon the over-
    all impact of the liner on long-
    term pollution patterns.  The
    real question should be:  how
    rapidly will pollutants move
    through a clay liner, what will
    the nature of the effluent be,
    and what are the environmental
    consequences of leakage?  Even
    the best of liners (clay or
    otherwise) are likely to develop
    leaks eventually, and an overall
    evaluation of that inevitable
    leakage is often overlooked.

WHAT ASSURANCES CAN BE PROVIDED THAT
CLAY LINERS WILL PERFORM AS INTENDED?

      At present very little is being
done to verify that clay liners are
performing as intended.  Significant
advances are needed in verifying the
suitability of the as-built liner.
Techniques are needed to measure the
actual leakage rate through a clay
liner.  The current philosophy is to
monitor aquifers beneath land disposal
units for detection of massive leakage.
However, this type of "negative" mon-
itoring provides no usable data on
those sites which are performing
properly.  Because the actual per-
formance of liner systems is so cri-
tical, more detailed monitoring
should be employed not only to detect
leakage but also to verify the actual
performance of the liner, be it good
or bad.  There are a number of ways
in which this might be done, but
little work has been initiated to
apply monitoring technology for very
slow rates of leakage through clay
liners.

CONCLUSIONS

    A common misconception is.that
clay liner technology is old and well
                                     271

-------
established.  While it is true that
clay liners have been used for many
years, it is not true that clay liner 2.
technology is well established.  In
the next few years, there are likely
to be substantial changes in the way
clay liners are designed and built,
and this should lead to the develop-
ment of a sound, verifiable liner     3.
alternative.  At present, the avail-
able data on field performance are
so sparse that it is impossible to
provide assurance that clay liners
are always performing as intended.
Clay liners may indeed turn out to
have an important place in the future
of waste disposal, but only if data
are developed that lend confidence    4.
to this technology.  The success of
earth scientists and engineers in
improving upon existing design, con-
struction, and verification pro-
cedures, along with development of
a data base that confirms the pro-    5.
per performance of clay liners,
is the key to the future of clay
liners.

ACKNOWLEDGMENTS

       The findings reported here re-
present conclusions from several
projects, including U.S. EPA Coop-
erative Agreement CR-810165-01 and    6.
National Science Foundation Grant
CEE-8204967.  This paper has not
been subjected to the EPA's peer
and administrative review and,
therefore, does not necessarily re-
flect the view of the EPA and no      7.
official endorsement should be in-
ferred.

REFERENCES

1.  Bowders, J.J., Daniel, D.E.,
    Broderick, G., and H.M.           8.
    Liljestrand, (1985), "Methods for
    Testing the Compatibility of Clay
    Liners with Landfill Leachate,"
ASTM SPT (in press).

Boynton, S.S., and D.E. Daniel
(1985), "Hydraulic Conductivity
Tests on Compacted Clay," Journal
of Geotechnical Engineering, Vol.
Ill, No 4, pp. 465-478.

Brown, K.W., Green, J.W., and
J.C. Thomas (1983), "The In-
fluence of Selected Organic Li-
quids on the Permeability of
Clay Liners," Proceedings, Ninth
Annual Research Symposium, U.S.
EPA, Cincinnati, Ohio, May 2-4,
EPA-600/9-83-018, pp. 114-125.

Brown, K.W., and D.C. Anderson
(1983), "Effects of Organic Sol-
vents on the Permeability of Clay
Soils," EPA, Cincinnati, Ohio,
EPA-600/2-83-016, 153 p.

Brown K.W., Thomas, J.C., and
J.W. Green (1984), "Permeabil-
ity of Compacted Soils to Sol-
vents Mixtures and Petroleum Pro-
ducts," Proceedings, Tenth Annual
Research Symposium on Land Dis-
posal of Hazardous Waste," U.S.
EPA, Cincinnati, Ohio, April 3-5,
EPA-600/9-84-007, pp. 124-137.

Daniel D.E, (1984), "Predicting
Hydraulic Conductivity of Clay
Liners," Journal of Geotechnical
Engineering, ASCE, Vol. 110, No.
2, pp. 285-300.

Daniel, D.E., and H.M. Liljestrand
(1984), "Effects of Landfill
Leachates on Natural Liner Systems,"
GR83-6, Geotechnical Engineering
Center, Univ. of Texas, Austin,
Texas.

Daniel, D.E., (1985), "Can Clay
liners Work?", Civil Engineering,
Vol. 55, No. 44, pp. 48-49.
                                    272

-------
 9.  Day, S.R., and D.E.  Daniel  (1985),
     "Hydraulic Conductivity of  Two
     Prototype Clay Liners," Journal
     of Geotechm'cal  Engineering,  Vol.
     Ill* No.  8, (in press).

10.  Foreman,  D.E., and D.E. Daniel
     (1984), "Effects of Hydraulic
     Gradient  and Method of Testing
     on Hydraulic Conductivity of
     Compacted Clay to Water, Methanol,
     and Heptane," Proceedings,  Tenth
     Annual  Research Symposium on  Land
     Disposal  of Hazardous Waste," U.S.
     EPA, Cincinnati, Ohio,  April  3-5,
     EPA-600/9-84-007, pp. 138-144.

11.  Gill ham,  R.W, Robin, M.J.L.,
     Dytynyshyn, D.F., and H.M.
     Johnston  (1984), "Diffusion
     Nonreactive and Reactive Solutes
     through Fine-Srained Barrier
     Materials," Canadian Geotechnical
     Journal,  Vol. 21, No. 3, pp.  541-
     550.

12.  Gordon, M.E., Huebner,  P.M.,  and
     P. Kmet (1984), "An Evaluation
     of the Performance of Four  Clay-
     lined Landfills in Wisconsin,"
     Seventh Annual Madison Waste
     Conference, U. of Wisconsin,
     Sept. 11-12, Madison, Wis.

13.  Hamidon,  A.B. (1984), "Organic
     Leachate  Effects on the Stability
     and Hydraulic Conductivity  of
     Compacted Kaolinite," M.S.  Thesis,
     Louisiana State Univ.,  Baton
     Rouge,  Louisiana, 183 p.

14.  Lambe,  T.W. (1954), "The Permea-
     bility of Fine-Grained Soils,"
     ASTM STP  163, pp.  456-467.

15.  Mitchel,  J.K. Hooper, D.R., and
     R.G. Campanella (1965), "Per-
     meability of Compacted Clay,"
     Journal ofthe Soil.Mechanics
     and FoundationsDivision, ASCE,
     Vol.  91,  No.  SM4,  pp.  41-65.

16.  Nasiatka, D.M.,  Shepherd,  T.A.,
     and J.D.  Nelson  (1981),  "Clay
     Liner Permeability in  Low  pH
     Environments," Symposium on
     Uranium Mill  Trail ings Manage-
     ment, Colorado State Univ., Fort
     Collins,  Colorado,  pp. 627-645.

17.  Peterson, S.R.,  Erickson,  R.L.,
     and 6.W.  Gee (1985), "The  Long-
     Term Stability of  Natural  Liner
     Materials in Contact with  Acidic
     Uranium Mill  Tailings  Solutions,"
     ASTM STP  874, (in  press).
                Di sclaimer

  The work described in this paper was
  not funded by the U.S. Environmental
  Protection Agency.  The contents do
  not necessarily reflect the views of
  the Agency and no official endorse-
  ment should be inferred.
                                     273

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  THERMAL CONTRACTION AND CRACK FORMATION POTENTIAL IN SOIL LANDFILL COVERS

               Orlando B. Andersland and Hassan M. Al-Moussawi
                          Michigan State University
                        East Lansing, Michigan  48824
                                  ABSTRACT

     Soil landfill covers in the northern states experience ground freezing to
depths of 2 m or more.  During periods of decreasing winter temperatures ther-
mal contraction will increase tensile stresses creating the potential  for
crack formation.  If elastic soil behavior is assumed, a drop of only 2 or 3°C
will generate significant tensile stresses.  Climatological data examined for
three locations, along with computed ground temperatures, show larger drops in
temperature.  Frozen cover soils are comparatively weak in tension.  Cracks,
once initiated, propagating unstably through the frozen soil, may extend
deeper than the tensile stresses to which they owe their growth.  Simple elas-
tic soil behavior used with thermal strains does not provide adequate informa-
tion for prediction of thermal contraction and crack formation.   Information
is needed on the linear thermal contraction behavior of frozen soils,  on the
extent to which soil creep will reduce the tensile stresses, and on criteria
suitable for preventing crack formation.  Needed research may provide methods
which are more economical than placement of additional cover soils to prevent
freezing.


INTRODUCTION                            the cover soils to the depth needed to
                                        relieve the tensile stresses.   The
     Frozen soil landfill covers are    cracks would be distributed over the
subject to thermal contraction, in-     cover surface in a pattern such that
crease in tensile stresses, and poten-  tensile stresses are reduced below the
tial crack formation during periods of  frozen soil tensile strength.   These
decreasing winter temperatures.  These  cracks normally would not be observed
temperature conditions occur annually   because they occur during winter cold
in the northern tier of states in the   periods, may be quickly covered with
continental U.S. and most of Alaska.    drifting snow, and may partially close
Potential cracking includes the full    with warmer ground temperatures.
depth of freezing, 2+ m in some loca-
tions.  Soil has a linear thermal co-        The magnitude of winter tempera-
efficient of contraction almost five    ture changes over short periods of
times higher than that of steel and a   time was determined by examining clima-
small decrease in temperature quickly   tological records for 3 locations
generates tensile stresses.  Because    (Lansing, Michigan; Madison, Wiscon-
frozen ground is relatively weak in     sin; and Fargo, North Dakota).  Ground
tension, initial fracturing commences   temperatures were calculated at several
at the ground surface and penetrates    soil depths as a function of time.

                                     274

-------
 Based  on  elastic  theory,  tensile
 stresses  were  computed for  the  frozen
 soil using available  soil thermal
 contraction  coefficients  and  the tem-
 perature  data.  A comparison  of these
 stresses  with  reported soil tensile
 strengths suggests  that crack forma-
 tion would be  predicted for all three
 locations.   The aepth of  crack  forma-
 tion will be dependent on soil  type,
 temperature, water  content, and any
 surface effects (vegetation,  snow
 cover, etc.) which  reduce the depth
 of freezing  temperatures.  Soil
 creep  in  tension  during the period of
 decreasing soil temperatures  will
 help reduce  tensile stresses  and
 crack  depth.   The results suggest
 that additional research  is needed to
 provide soil parameters required for
 accurate  prediction of tensile
 stresses  and to provide design  cri-
 teria  suitable for  preventing crack
 formation in soil landfill covers
 exposed to freezing temperatures.

 BACKGROUND INFORMATION

     Landfill covers designed to
 serve multiple functions will  be
 layered in some fashion as illustra-
 ted in Figure 1.  The top of  a  cover
 typically will be a loose, loamy soil
 suitable for supporting vegetation.
 The underlying clay barrier layer is
 a critical cover  component because it
 is intended to minimize the transmis-
 sion of water that would contribute
 to leachate generation and of gas
 that might kill vegetation and  pose
 an explosion or other hazard.   A
 buffer or foundation layer, sand or
 other  soil, protects the barrier from
 damage.  A buffer soil may also be
 placed above the clay barrier layer
 to increase depth in areas of deep
 frost penetration.  Soil  densities
will  correspond to those accomplish-
 ed during spreading of cover soil
with  dozers and other compacting
 equipment.  The topsoil  is placed in
 a  loose condition  and  not compacted.


              1ft1'l11'l'l 11
              S11.T (FII.TERI
            i'"S SANOIBUFFBRI
Figure 1,  Two representative systems
           for layered solid waste(l).

     Thermal contraction behavior and
tensile strengths of frozen cover
soils are dependent on several vari-
ables including soil type, ice and
mineral volume fractions, temperature,
and degree of ice saturation.  The
topsoil (loam) may involve several
types (1) including silty gravels,
clayey gravels, silty sands, clayey
sands, inorganic silts, and inorganic
clays.  Above the water table these
soils will be only partially saturated
with the degree of saturation related
primarily to particle size.  Soil type
and water content determine the ice
fraction when frozen.  An approximate
relationship between effective grain
size and degree of saturation for
soils located above the water table
in temperature zones with moderate
rainfall is shown in Figure 2.  The
D10 particle size corresponds to 10
percent of the sample finer by
weight.  The loam topsoils listed by
Lutton (1), with degrees of saturation
                                      275

-------
Intermediate to sand and silt, will
have reduced frozen tensile strengths.
The clay barrier layer will be close
to or at full saturation with large
unfrozen water contents.  Other
factors involved in the tensile be-
havior of frozen soils will be out-
lined later.
Figure 2.  Approximate relationship
           between effective grain
           size and degree of satura-
           tion in the zone of soil
           moisture in temperate
           zones with moderate
           rainfall (2).
SURFACE AND GROUND TEMPERATURES

     Ground temperatures are deter-
mined by the air (or surface) tempera-
tures, heat flow from the interior of
the earth, and soil thermal proper-
ties.  Surface temperatures undergo
approximately simple periodic fluctua-
tions (Figure 3a) on both a daily and
an annual cycle.  Meteorological data
for a given location are used to pro-
vide the mean annual temperature (Tm)
and the surface temperature amplitude
 As).  The ground surface temperature
 T(s,t)) can be reasonably estimated
as a'sinusoidal fluctuation which
repeats itself daily and annually,
thus
                                                    = T
                                                       m
                      sin
(1)
                                        where t is time and p is the period,
                                        24 hours or 365 days.  This'tempera-
                                        ture pattern is attenuated with depth
                                        (x) and, in a homogenous soil  with no
                                        change of state, the temperature
                                        (J/K -j.\) at any depth can be calcu-
                                        lated as
                                                       m
                                                                           sin
where a is the soil thermal diffusi-
vity and heat flow from the interior
of the earth is assumed to be negli-
gible.  The simple solution repre-
sented by equation (2) indicates the
trends found in actual ground tempera-
tures but, in practice, they can be
significantly modified by the effects
of latent heat, differences in frozen
and thawed soil thermal properties,
non-homogenous soils, non-symetrical
surface temperatures because of sea-
sonal snow cover, vegetation, and
other climatic influences.

     Thermal contraction and develop-
ment of tensile stresses in the frozen
                                     276

-------
     (a)
      Q.
      I
                           Surface temperature  Tu,, « T m «• A,


                         Temperature
                         at depth x   T I..H = T» + A » e
                               Mean annual
  Mean annual    /   *
^temperature (Tm) j  /
                                                 Time(n
                                                   A = amplitude of surface
                                                       temperature, °C,
                                                   A = temperature amplitude
                                                       at depth x,
                                                   p = period, 24 hours or 365 days,
                                                   d—= thermal diffusivity.
     (b)
      T, - Tmi A, 6
                                  Level of negligabte temperature amplitude
                     (Depth)
Figure 3.   Surface and ground temperatures (3).  (a)
            (b)   Temperature attenuation with depth.
                           Sinusoidal  fluctuations.
soil cover will  be most critical
during a period  of relatively rapid
decrease in  temperature.  To deter-
mine the magnitude of these tempera-
ture changes climatological records
for 3 locations  (Lansing, Michigan;
Madison, Wisconsin; and Fargo, North
Dakota) have been examined with
selected data summarized in Figure 4.
These data may not include the larg-
est negative temperature gradients
since only a partial  examination of
the available temperature records
was made.  The record temperature
             drop experienced by large  areas of
             the central U.S. on the  night of
             January 20, 1985, may be more severe
             than the data reported in  Figure 4.
             Variations in temperature  from the
             sine curve shown in Figure 3 are a
             result of winter weather changes.
             Note that at all three locations the
             freezing temperatures decreased more
             than 15°C in a 12 hour period.  Cold-
             er  temperatures at Madison,  Wisconsin,
             and at Fargo, North Dakota,  would
             penetrate the soil cover to  a greater
             depth, hence more frost  penetration.
                                      277

-------
    Table 1.   Maximum frost depths  for
              the three locations during
              the year (Figure 4) for
              sand,  silt,  and  clay  soils.
Figure 4.  Selected air temperatures
           at three locations showing
           a rapid decrease over a
           24-hour period.

     The depth of ground freezing
(frost penetration) can be calcula-
ted using the local freezing index
and soil thermal properties.  The
freezing index is defined as the
cumulative degree-days (below 0°C)
for one winter season and corresponds
to the area between the 0°C line and
the negative part of the surface tem-
perature curve in Figure 3a.  The
modified Berggren equation (4) ac-
counts for phase change and gives the
frost penetration in terms of the
soil thermal conductivity, the ground
surface freezing index, and soil
latent heats.  For comparative pur-
poses, the computed maximum frost
depths for each location and year
included on Figure 4 are listed in
Table 1 for three soil types.  The
frost depths at each site listed in
Table 1 can be larger since the









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-------
 the  cover  topsoils and the clay bar-
 rier layer.  Note that the greater
 frost depth corresponds to sand with
 a  lower water content.  The poten-
 tial  for cracking includes the full
 frozen soil depth.

      Frozen soils behave elastically
 in response to rapid deformations.
 If one assumes the same behavior for
 the  slower natural thermal contrac-
 tion, the tensile stresses generated
 would be proportional to the amount
 that the temperature drops from some
 reference temperature.  To provide
 more  information on the rate of tem-
 perature drop at various depths,
 computed temperatures in clay are
 summarized in Figure 5 for Fargo,
 North Dakota, on 2-3 February 1974.
 Using a step change in surface
 temperature and the LaPlace-transform
 technique (5), soil  temperatures were
 computed as a function of time at the
 depths shown in Figure 5.   The zero
 depth represents the ground surface.
 Lachenbruch (6) reported that signi-
 ficant tensile stresses would be
 generated in frozen soil  with a tem-
 perature drop of only 2 to 3°C.  The
 temperature change in 9 hours at the
 24 cm depth falls in this  category.
With more time, similar temperature
changes would occur at greater depths.

THERMAL CONTRACTION, TENSILE
STRESSES, AND SOIL STRENGTH

     On cooling,  the frozen soil
cover surface would  contract if it
were not constrained.   Horizontal
tensile stresses  are generated with
no observable horizontal  strains.
The horizontal  thermal  strain is
given by the thermal  contraction,
thus,
        = e.
                                 (3)
where a is the coefficient of linear
contraction (about 5 x 10~5oc-l for
                                                                             JZ

                                                                            CM »
                                         Figure 5.
Computed ground tempera-
tures in sand for Fargo,
North Dakota, on 2-3 Feb-
ruary, 1974.
                                         frozen sand), L0 is the length at
                                         some reference temperature, and AL is
                                         the change in length due to a temper-
                                         ature change AT.  With the soil con-
                                         strained and if the frozen soil is
                                         assumed to behave elastically the
                                         tensile stress becomes
                                                 =  E
                                                   T^T ey
                                                          _  E
                                                          "
                                                                           (4)
                                         where E is Young's modulus and u is
                                         Poisson's ratio.   The stress-strain
                                         curves for sand (Figure 6} in tension
                                     279

-------
  1.0
        0.01
              0.02   0.03
                AXIAL STRAIN
                          0.0ft
                                0.05  0.06
Figure 6.  Stress-strain curves for
           frozen sand in compres-
           sion (c) and tension (t)
           with test duration (t) in
           hours (8).

at 45% gives an E close to 435
kN/cm2.  Using this value with

U = 0.28 gives ^-=600 kN/cm2 or

Oy-0.03  J (kN/cm2) for equation (4).
The tensile strength of the saturated
frozen sand in Figure 6 is at most
only 0.4 kN/cm2 indicating that
frozen sand will be very sensitive to
a temperature decrease.  Note that
failure stresses in tension are much
smaller (Figure 6).  With only par-
tial saturation for frozen cover
soils, tensile strengths would be
further reduced since only the ice
matrix is able to transfer tensile
stresses.  Considering the data sum-
marized in Figure 5 and assuming
elastic soil behavior, the frozen
soils would be close to failure in
tension before the rapid air tempera-
ture drop occurs.  The additional
temperature decrease shown in Figure
5 would cause additional thermal
contraction and larger tensile
stresses.  The total tensile stress
would then be significantly greater
than the tensile strength of the
frozen saturated sand and open
cracks would be predicted.  For the
given assumptions Lachenbruch (6)
states that the crack spacing would
be no greater than the crack depths.

     The example with sand illus-
trates that simple elastic behavior
does not fully represent the frozen
soil behavior.  Frozen soil under a
constant stress will deform with time
in a viscous manner.  This creep be-
havior would serve to reduce the ten-
sile stresses over the period of time
in which temperature is decreasing.
If a viscous deformation law is as-
sumed the stress would be propor-
tional to the rate at which the tem-
perature drops.  The rate of tempera-
ture decrease at various soil depths
is represented by slopes of the
curves in Figure 5.  The data in
Figure 6 also show that Young's modu-
lus increases with a decrease in tem-
perature so that the problem becomes
more complex.  Experimental data are
needed which describe the rate of
increase and magnitude of tensile
stresses which develop in typical
cover soils for freezing temperatures
and cooling rates representative of
the northern tier of states.  The
lack of information on linear thermal
contraction behavior for these same
soils indicates additional research
needs before an accurate analysis of
thermal cracking in the cover soils
can be made.

CONCLUSIONS

     1.  A review of the mechanics of
thermal contraction indicates that
cracks propagating unstably through
the frozen cover soils may extend
deeper than the tensile stresses to
which they owe their growth.  Under
suitable conditions it appears that
the cracks may penetrate the frozen
cover creating an opening for water
                                     280

-------
movement and escape of gases.

     2.  Information on the linear
thermal contraction behavior of
frozen soils needed for computation
of thermal  strains is lacking.   The
dependence of the coefficient of
linear contraction on various soil
parameters should be determined.

     3.  Simple elastic soil beha-
vior used with thermal strains  does
not provide the information needed
for accurate prediction of thermal
contraction and crack formation.
Information is needed on the rate
of increase and magnitude of tensile
stresses which develop in frozen
cover soils for freezing tempera-
tures and cooling rates representa-
tive of the northern tier of states.

     4,  Using information from
items 2 and 3, criteria need to be
formulated which will permit predic-
tion of cracking and the techniques
suitable for preventing crack forma-
tion.  New techniques may be more
economical  than placement of addi-
tional cover soils to prevent freez-
ing and possible cracking of the
clay barrier.

REFERENCES

1.  Lutton, R.J., "Evaluating cover
    systems for solid and hazardous
    waste," Publication SW-867,
    USEPA-MERL, Cincinnati, Ohio,
    September 1982.

2.  Terzaghi, Karl, "Permafrost,"
    Journal of the Boston Society of
    Civil Engineers, The Engineering
    Center, Suite 1110, Boston,
    Massachusetts, Vol. XXXIX,  No.
    1, January 1952.

3.  Smith,  D.W., Reed, S., Cameron,
    J.J., Heinke, G.W., James,  F.,
    Reid, B., Ryan, W.L., and
    Scribner, J., "Cold climate de-
    livery design manual," Publica-
    tion EPA-600/8-79-Q27, USEPA-
    ERL, Corvallis, Oregon, Septem-
    ber 1979.

4.  Aldrich, H.P., Jr., and Paynter,
    H.M., "Analytical studies of
    freezing and thawing of soil,"
    Technical Report No. 42, Artie
    Construction and Frost Effects
    Laboratory, New England Divi-
    sion, U.S. Army Corps of
    Engineers, Boston, Massachusetts,
    1953.

5.  Arpaci, Vedat S., CONDUCTION HEAT
    TRANSFER, Addison-Wesly Publish-
    ing Company, Reading, Massa-
    chusetts, 1966.

6.  Laehenbruch, Arthur H., "Mecha-
    nics of thermal contraction
    cracks and ice-wedge polygons in
    permafrost," Special Paper No.
    70, The Geological Society of
    America, 1962.

7.  Local Climatological Data for
    Fargo, ND, Lansing, MI, and
    Madison, WI.  National Oceanic
    and Atmospheric Administration,
    National Climatic Center, Ashe-
    ville, North Carolina.

8.  Eckardt, H., "Creep tests with
    frozen soils under uniaxial ten-
    sion and uniaxial compression,"
    The Roger J.E. Brown Memorial
    Volume.  Proceedings of the 4th
    Canadian Permafrost Conf.,
    Calgary, Alberta, March 2-6,
    1981.  H.M. French (ed.), Nation-
    al Research Council of Canada,
    Ottawa, pp. 365-373, 1982.

               D1sclaimer

 The work described in  this  paper was
 not funded by  the U.S.  Environmental
 Protection Agency.   The contents do
 not necessarily reflect the views of
 the Agency and no official  endorse-
 ment  should be inferred.
                                    281

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SYNTHETIC I»INER SELECTION AND APPLICATION TO GROUNDWATER PROTECTION

       John D. VanderVoort, Schlegel Lining Technology, Inc.

                             ABSTRACT
     This paper discusses the use of synthetic liners as a
means of controlling groundwater pollution.
     It discusses the most common types of raw materials for liners:
chlorosulfonated polyethylene, polyvinyl chloride and polyethylenes,
and other liner materials: butyl rubber, chlorinated polyethylene,
ethylene propylene diene monomer and chloroprene.
     The manufacturing processes are described for producing the final
synthetic liner including calendering, blown film and sheet extrusion.
     The various seaming methods for factory and field seaming are
defined and include adhesive seams, extrusion, hot air, bodied solvent
and solvent seams.
     Causes of failure are presented such as chemical attack, puncture
and tear, and biological.  Also, the paper presents information on how
to select a lining system for a particular application.
     The emphasis throughout this paper is on specifications for all
segments of the synthetic liner industry, and guidelines for the end
user on how to determine if the product meets those specifications.
     A flow chart for quality control and selection for various synthetic
liners is presented.
Introduction

    In recent years, the need for
containment of hazardous wastes has
received much attention as the
potential dangers to public health
from these substances receive closer
scrutiny from both the public and
private sector.  This paper deals
specifically with the use of extruded
polymers as perhaps the most
effective means of containing
hazardous wastes.  Also it describes
some lining materials in use today,
methods of manufacture and some
common failure mechanisms.
Background and Materials Available

    Throughout history, soils and
clays have been the most common
lining materials.  These substances
have never been considered perfect
liners as they do not provide zero
permeability.  Since both organics
and inorganics dissolve parts of clay
structures, permeability usually
increases over time.

    Many polymeric materials will
exhibit essentially a zero
permeability rating when used in a
film or sheet form.  As a result,
                                     282

-------
these materials offer long-term
containment possiblities for ground
water protection.  The first
polymeric materials used for this
purpose were synthetic rubbers in the
1940s,  By the 1970s, many new
synthetic lining materials,
particularly thermoplastics, were
available.

    Today synthetic liners are used
to contain hazardous wastes, protect
groundwater and control erosion.
There are a variety of applications
and a variety of lining materials.

Liner Materials

    The most commonly used base
materials for synthetic liners are:

    Chlorosulfonated polyethylene
(CSPE), a polymer produced by
reacting polyethylene in solution
with chlorine and sulfur dioxide.
CSPE contains 25 to 45 percent
chlorine and 1.0 to 1.4 percent
sulfur, both by weight.  The presence
of chlorine and sulfur side-chains in
the end product has a noticeable
effect on its chemical compatibility
with hydrocarbons.  CSPE exhibits
poor resistance to both aliphatic and
aromatic hydrocarbons, chlorinated
solvents, oxygenated solvents and
alcohols.

    Polyyinyl chloride (PVC), a
polymer produced by the polymeri-
zation of vinyl chloride monomers,
with plasticizers added to improve
flexibility.  Because it also contains
side-chains of chloride, it offers
limited resistance to hydrocarbons,
PVC blended with ethyl acetate also
has side-chains.

    Polyethylenes, because of their
simple chemical structure, exhibit
the best resistance to hydrocarbons,
as well as to other chemicals.
Laboratory tests have shown that the
higher the density, the greater the
resistance to chemicals, including
hydrocarbons.

    Other, but less commonly used,
base materials are:

    Chlorinated polyethylene (CPE),
produced by chemical reaction between
chlorine and polyethylene.  The
resulting polymer is 25 to 45 percent
chlorine by weight and contains
side-chains of dissimilar members.
CPE has excellent flexibility but
limited resistance to hydrocarbon
environments.

    Ethylenepropylene diene monomer
(EPDM), a terpolymer of ethylene,
propylene and a small amount of
nonconjugated diene to furnish
vulcanization sites.  The material
has good chemical resistance except
with hydrocarbons.

    Epichlorohydrin rubber, a
synthetic rubber that includes two
epichlorohydrin-based elastomers,
which are saturated, high molecular
weight, aliphatic polyethers with
chloromithyl side-chains.

    All of the above polymers
mentioned have been successfully used
in a variety of containment
applications.  However, some of them
have also failed.  These failures can
be attributed to poor selection, poor
installation and/or changes in the
containment application at a later date,

    Butyl rubber, elasticized
polyolefin and polychloroprene are
the least commonly used base
materials.

    In addition to base polymers,
there are blends and combinations of
the above which are used either alone
or with other additives.  These
additives include: plasticizers for
improved flexibility; crosslinking
                                       283

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agents for promoting the formation of
chemical bonds; fillers to give body;
pigments for coloring purposes; bio-
logical inhibitors to reduce suscep-
tibility to attack by microorganisms;
and scrim reinforcement for improved
mechanical strength.

    These additives are used to
overcome an inherent weakness in a
base material, but their use must
also be suitable in contact with the
contents of a containment system.

Manufacture of Synthetic Liners

    Flexible membrane liners are
produced into a film or sheet by one
of three processes; blown film,
calendering or sheet extrusion.  In
the blown film process, molten
plastic is extruded through a. tubular
die in a vertical direction.  Air is
blown through the die to form a
bubble.  After the bubble is cooled
from the outside, it is flattened at
the top of its travel by a collapsing
frame.  The resultant film or sheet
is then passed through a wind—up
system.  The blown film process is
most commonly used to make thin
polyethylene film, 10 to 30 mil in
thickness.  With this process the
size of the sheets is limited.  It
must be noted as well that some
blown-film liners contain a lubri-
cant, typically calcium stearate, to
facilitate extrusion through the
circular die.  This peculiarity of
some blown—film liners must be taken
into account when the seaming method
is specified; a process that employs
preheating will likely cause the
lubricant to migrate to the surface
and interfere with seam integrity.
The collapse and wind-up process may
also subject the liner to unaccept-
able tensile stressing.

    Most lining materials are
produced by the calendering process,
with the exception of some of the
polyethylenes.  Calendering is really
a form of extrusion with rotating die
nips.  A typical operation contains
four rolls forming three nips.  The
first is the feed pass, the second is
the metering pass and the final nip
is the sheet forming, gauging and
finishing pass.  The most typical
liner width produced by calendering
is five feet, although some calenders
are 10 feet wide.  Thickness of
lining material produced by this
process is generally limited to 10 to
60 mil.

    With the sheet extrusion process,
molten plastic is forced through a
die to form the fianl width of sheets
desired.  Sheets made by the extru-
sion process can be made in thick-
nesses as great as 250 mil, although
80 to 100 mil is more typical.  One
manufacturer is able to extrude
sheets that are 34 by up to 900 feet
in length for few field seams.

    It is important to consider what
services the liner manufacturer will
provide in addition to producing the
liner panels.  Figure I is a flow
chart depicting the various functions
that should be examined when con-
sidering a polymeric material.

    In the majority of liner
applications, site engineering work
is done for the operator of the final
facility by a consulting or in-house
engineer who recommends the required
amount of lining material to cover
the application.  The manufacturer in
those cases only supplies the lining
material.  After manufacture, the
liner is turned over to fabricators
for finishing and factory seaming and
then to installers, or contractors,
who complete the project.  Each party
in this typical factory-to-field
scheme is an independent firm.
                                      284

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    When designing a secure
containment application, numerous
factors involved in the complete job
should be considered, with particular
attention to seaming methods,
chemical resistance, puncture and
tear resistance and resistance to
biological attack.

Seams and SeamingMethods

    All liners are seamed, either in
the factory or the field or both.
Because seams are the most obvious
weak points of a lining system, they
must meet all the specifications for
the liner itself.  Seaming methods
include:

    Adhesive seams are joined
together with a chemical adhesive
system that bonds together two
separate membrane surfaces.
Generally, a two-component system is
employed that requires care in
mixing.  When the adhesive is
applied, the residence time before
bonding, pressure applied and timing
of pressure are all critical.  These
variables may be difficult to control
in a field situation.

    With a bodied solvent seam,
lining material is dissolved in a
solvent used to soften and bond liner
surfaces together.  This method is
essentially an adhesive seam made up
of the parent material.  Because
problems with application, timing and
pressure do exist and the amount of
solvent used is critical, field
application requires extreme care.

    Dielectric seams are made when a
high frequency current is used to
melt the surfaces of the membrane
material so that they can be
homogeneously bonded together under
pressure.  This process is used most
often for factory seams, because the
use of high frequency current is
difficult to control in the field.
     Forextrusion welded seams, a
bond is obtained between two flexible
membranes by extruding a molten
ribbon of the parent material between
overlapped pieces of liner material
followed by applied pressure.  This
is a relatively straightforward task
in the field.

     Solvent seams use solvents to
softens the surfaces to be bonded.
Generally pressure is then applied to
the seam.  Under field conditions,
the application of the solvent, and
timing and pressure can be a
difficult task.

     A chemically adhesive tape seam •
may be used to bond liner surfaces
together.  The tape system adds an
additional element to the seam system
that must be assessed for the
requirements of the application.
Taped seams are commonly made in the
field and are subject to all the
hazards associated with adhesive
seams.  The adhesive is different
material and must meet criteria and
needs of application.

     To make thermal or fused seams,
high temperature air or gas is
applied between the two surfaces to
be bonded until the membrane surfaces
melt.  At that'time pressure is
applied to create a homogeneous bond
between the two surfaces.  Timing and
pressure are critical and must be
carefully controlled.  The recent
development of a process that grinds
material from the bonding surfaces
and incorporates it into the seam is,
in this author's opinion, one to be
avoided because of the risk of
encapsulating sand or dirt
particles.  Foreign material within a
seam likely signals a void.
                                       285

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     Vulcanized seams are formed when
the areas to be bonded are unvulcan-
ized material that are cured together
with heat and pressure.  This method
is applicable only for thermoset
materials.

Chemical Resistance

    The primary purpose of a
synthetic liner is to protect
groundwater from contamination.
Obviously the liner itself must be
resistant to the chemicals being
contained.  When considering chemical
resistance, the operating temperature
of an impoundment as well as the
potential for exothermic chemical
reactions must be taken into
account.  Whenever possible, chemical
compatibility tests are recommended,
even urged, to assure that a liner
material is an appropriate one for
the operating uses in question.

Puncture and Tear Resistance

    It is impossible to over
emphasize the importance of liner
thickness to the integrity of the
overall lining system.  The puncture
and tear resistance of a given
plastic material is related directly
to its thickness and approximates a
geometric function.  In tests to
determine the relationship of high
density polyethylene (HOPE) liner
thickness to puncture resistance, DIN
16 727 describes a single point
application of high physical stress
at high deformation speed, a
stressing mode that can occur easily
at an installation site.  Results
showed that the height of fall from
which no damage takes place triples
when liner thickness is doubled, from
1,5mm to 3.0mm for example.

    In tests of a HOPE liner for tear
resistance in accordance with DIN 53
515, a Graves angle test specimen is
subjected to tensile stressing at a
speed of 500mm (20in.) per minute.
The test simulates rapid tearing as
would likely be found in actual site
conditions, and shows that as liner
thickness is doubled, tear resistance
also doubled.

    Another critical aspect of
specifying liner thickness is the
ability of a given thickness to
accommodate the almost inevitable
subsoil settling that can be expected
under most impoundments.  The design
engineer must ensure that the liner
material is sufficiently strong and
thick to withstand the multi-axial
tensile loading and to alleviate
localized stress points with
sufficient elongation behavior.

Resistance to Biological Attack

    A potential failure mechanism for
lining systems and one that is often
overlooked is biological attack.  Any
polymeric material containing plasti-
cizers will likely be subjected to
microbiological attack.  Microbes
actually consume certain organic
plasticizers; as the plasticizer is
lost, the liner becomes less flexible.
Eventually it will become brittle and
crack.

    Small rodents and burrowing
animals sometimes use a liner as a
food source, even to the point of
becoming addicted to certain
plasticizers.  Linings containing
rodent food sources should not be
specified for areas where rodent
populations are known to be active.
Rats can gnaw through a liner in
unexpected locations making it
difficult to isolate and repair any
leaks.

    Thin (60 mil or less) synthetic
liners are also susceptible to
peneration of roots and plant life
through them.  Soil sterilization is
a distant alternative to the better
                                       286

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 choice of  specifying a thick  liner
 that  is  impenetrable to  such  plant
 life.

 Conclusion

    The  use of extruded  polymers for
 the containment of hazardous  wastes
 is a  vitally  important and beneficial
 use of plastic and rubber materials.
 The details that factor  into  a,well
 thought-out specification, however,
 are numerous  and sophisticated.  This
 paper has  highlighted some of the
 fundamental design and specification
 issues that must be considered so
 that  a lining system services both
 the user and  the public.
              Di sclaimer
The work described in this paper was
not funded by the U.S. Environmental
Protection Agency.  The contents do
not necessarily reflect the views of
the Agency and no official endorse-
ment should be inferred.
                                     287

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                                  SITE SELECTION
                                              SITE PREPARATION
ro
O3
CO
TYPE OF APPLICATION
                      Engineering  Design—^
                      Access  Road	
                      Unloading  Area	
                      Storage Area-
                                     Transport Vehicles	
                                     Water Drainage System-
                                     Securement Trenches-
                                     Surface Preparation for Liners
                                     Compacted Sub-Soil Surfaces
                                     Pipes, Sumps, Concrete Supports

                                              Installation Equipment
                                              Liner Delivered	
                  Basins
                  Canals
                  Curtain Walls
                  Dams
                  Renovations
                EVALUATION OF NEEDS
                     LINER SELECTION
                                                                                               FIGURE  I

                                                                                              FLOW CHART
            LINER INSTALLATION
Ventilation-
Cover Embankments^
Cover Bottom
                      —Physical  Properties
                      —Chemical  Resistance
                      -WeatherablHty
                      —Temperature Extremes
                      —Bacteria  Attack
                        Rodent Resistance
                      —Tear Resistance
                      —Long Term Aging
                      I—Repa1rab1lity
Secure Top Edges—
Seal to Pipes, etc«
Drainage-
                                                                          Leak Detection System-
                                                                          Extracting System-
Testing of Installation-
Repairs if Necessary	

-------
                       SLURRY WALL MATERIALS EVALUATION
                      TO PREVENT SROUNDWATER CONTAMINATION
                          FROM ORGANIC CONSTITUENTS
                Ken E. Davis, Marvin  C. Herring and J. Tom Hosea
                           KEN E.  DAVIS ASSOCIATES
                               3121  SAN JACINTO
                            HOUSTON, TEXAS  77004
                                   ABSTRACT

     The Installation of earthen  liners  and slurry wall trenches  constructed of
soils treated with bentonite and/or  bentonite/cement mixtures are frequently  used
today  as a means to retard or control the  flow of  contaminants from  surface
impoundments and landfill disposal  areas.  Although effective in reducing the  rate
of flow  of water and some contaminants, standard bentonite treatment is not always
effective  in controlling  some types of  contaminants,  such as chlorinated
hydrocarbons.

     Past handling and disposal of  liquid chlorinated hydrocarbon waste in earthen
impoundments and a landfill at an existing plant resulted in shallow ground water
and  soil contamination over  a broad area.  Following field investigations,
extensive  laboratory tests  were conducted to  investigate  the feasibility  of
confining  the  plume of  contamination through the installation of  a slurry trench
barrier.  Specially designed methods  of testing  were  used during  the
investigation.

     Standard bentonite soil mixtures using up to 6% or more bentonite were shown
to be ineffective in restricting the flow of the concentrated wastes found  in  the
subsurface strata.   However,  a 12%/12% bentonite/cement dust soil mixture was
shown to completely restrict the flow or movement of the concentrated waste while
reducing the flow of ground water and contaminated leachate.
INTRODUCTION AND PURPOSE

     Bentonite, or more specifically
the clay mineral montmorillonite, has
been  used for decades to impede  or
reduce  the flow  of water  through
permeable soils.  This characteristic
has been widely used in the drilling
and construction industries.

     The use  of bentonite began  in
the petroleum  exploration  industry
during  the 1920's in drilling muds
used to seal the  sides of  the hole
and to provide  other  benefits which
aided the drilling  operation.   During
the 1940's, it was found that borings
and trenches could be kept open using
a slurry of bentonite, and that  the
resulting trench when  backfilled
exhibited a reduced  permeability to
the horizontal flow  of ground water.
More recently, bentonite  slurry wall
trenches have found  application to
control  pollution migration   for
improperly designed  waste  landfills
and impoundments.

     The design  of  soil bentonite
slurry  walls  for  conventional
groundwater control  applications  has
been widely documented.  Other than
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normal  standard testing, very little
Investigative work is required.  The
design  of  a  soil-bentonite slurry
wall  for waste  containment however,
requires  site specific studies in
order to determine the effectiveness
of the proposed  barrier.

APPROACH

Test  Program

     The presence  of  organic or
inorganic  compounds  in   the
groundwater can  have a detrimental
effect on the  bentonite slurry wall
and its  ability to  contain contami-
nants.   Certain  chemicals can affect
the chemical/physical properties of
the bentonite  and cause  ailure of
the barrier either  during construc-
tion  or  at  some time in the future.
Therefore,  the  effects of the  ground-
water, waste leachate or liquid waste
on the soil/bentonite system  must be
determined  prior to the preparation
of final design specifications for
the slurry wall.

     Prior  to the start of laboratory
investigations,  detailed field
investigations  are essential to
determine the  geohydrolpgy  of the
proposed slurry trench site.   Unless
detailed information is available!,
sufficient soil  borings should be
made  of  the entire area to define the
geology, particularly within  the area
in which the proposed trench will be
located.   In  addition, sufficient
pump  tests  and field permeability
tests should  be made to define the
hydrology of the area.

     During the course of the field
investigations, chemical analysis
should be made  on the groundwater and
core  samples to  define the extent of
the contamination plume.  Samples of
soil, the  waste, groundwater and
leachate should be  collected  for use
in subsequent laboratory evaluations
of the  proposed  slurry  trench
composition.
     In  this  paper,  the  authors
describe the laboratory  investiga-
tions conducted during  the evaluation
of a proposed  slurry trench barrier
to  contain  contamination  from an
existing industrial disposal area.

Site Description

The  site  for  the proposed slurry
trench barrier was an  old disposal
area within a large  petrochemical
manufacturing  plant that had  been
used for various  waste activities in
the  past.   This included  the
collection  and storage  of liquid
chlorinated  hydrocarbon wastes in
earthen  pits or ponds  and  the
landfill disposal  of solid  organic
and  inorganic wastes, drums of
miscellaneous liquid organic wastes,
plus construction debris  such as
wood, concrete, etc.

     The  field  investigations
indicated that  extensive  shallow
groundwater and soil  contamination
had occurred.   In  addition,  immis-
cible and  relatively pure undiluted
waste organics were found to exist at
points more  than  300 feet away  from
the  original  source  and  down to
depths as  great as 50-60 feet below
the surface.

Site Geology

     The geology of  the area  was
characterized  by  a combination of
hydraulic  and  mechanical fill over-
lying deposits  of  recent alluvium.
Extensive  geological investigations
of the  area were conducted  and a
detailed  description  of this area
developed.

     The proposed area where  the
slurry  trench barrier  would be
constructed  was on the eastern  edge
of the disposal area.  Several  core
borings were  drilled in  this area.

     The geology of  the proposed
slurry trench area was  characterized
                                   290

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by several distinct layers of soil.
The area is  covered with a layer of
silty clayey sand fill material from
the surface to a depth of approxi-
mately 12  to 14  feet  below  the
surface.   Beneath  this on the
northern end of the proposed trench
area is a soft black  organic clay
layer  approximately 4 to 6 feet thick.
Beneath this is a layer of fine  to
medium silty sand approximately 25 to
 5 feet  thick that  extended downward
to a depth of 50 to 60 feet below the
surface.   Underlying these soil
layers is a stiff light gray to tan
clay found at depths of 50 to  60 feet
below  the surface throughout the area.
Electric logs of wells in the area
indicate the thickness of this base
clay layer to be 75 to 100 feet.

    Samples  of  soil  and groundwater
taken  from core borings show the soil
and water in the area of the proposed
slurry trench to  be contaminated with
chlorinated hydrocarbons. Data from
samples show  contamination was
present at various depths down to the
base clay  encountered at a depth  of
57 feet below the surface.  Contin-
uous samples were  not  taken for con-
tamination analysis from all borings.
However, a composite of samples taken
at  2  feet  intervals showed high
levels  of  contamination.   Visual
evidence  of  high  concentrations  of
phased  organic contaminants was
noticed during  the drilling  opera-
tion,  especially at  depths   of
approximately 12  through 20 feet
below the  surface.   An composite
analysis of samples taken at 2 feet
intervals from the  depths of  2 to 65
feet  below the surface showed  the
soil  contained  0.59 wt.%  total
chlori-nated hydrocarbons.   These
results are presented on Table  1.
Groundwater  samples  taken from  the
same  location contain 942  ppm  of
total chlorinated  hydrocarbons  as
shown  on Table 2.
    TABLE 1.  CHEMICAL  ANALYSIS OF
      COMPOSITE SOIL MIXTURE  B
Compound
       Wt.
Methyl  Chloroform             0.02
Trichloroethylene            <0.01
Trichloroethane              0.03
Perchloroethane              0.04
Tetrachloroethane             0.01
Tetrachloroethane  (Sym)       0.06
Pentachlorobutudiene          0.10
Hexachlorobutane             0.05
Hexachlorobutadiene           0.26
Unknown                      0.02
             Total           DTW

     TABLE 2. SROUNDWATER ANALYSIS
Component
Concentration
    mg/1
Chloroethylene             0.80
Chloroethane               0.04
Methylene chloride          0.15
1,1 -  Dichloroethene       25.9
1,1 -  Dichloroethane        4.08
1,2 -  Dichloroethene
Trichloromethane         513
1,2 -  Dichloroethane        4.82
1,1,1, - Trichlorethane     4.82
Tetrachloromethane
Trichloroethene            7.12
1,1,2  - Tricholrothane    260
Tetrachloroethene         126
             Total       942

Method of Test

    A standard method of test for
evaluating the inhibiting effects of
soil  additives  to migration  of
organics  through  soils  was  not
available.  Therefore, modification
of standard  permeability testing of
soils  was required for this work.

    A constant head permeability
method of test was  utilized through-
hout  the  laboratory investigation.
However,  instead of  using  the
standard up-flow of fluid through the
core to be tested, a downward  flow
was  used  in  all  cases.  A  flow
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diagram of the  test apparatus is
presented on Figure 1.

Figure 1.  Permeability Test Unit
                    PRESSURE SOURCE
       Ti»T UNIT      FLUIO BEaEBVOIR
     The  test apparatus was  con-
structed from major component parts
purchased from Soil Test, Inc.  This
included  one high  pressure K-670
Miniature Permeater Unit plus two
additional K-620  Soil Test Permeater
Units.   These were connected  to
enable three simultaneous permeabi-
lity tests.  Subsequently, a second
test unit  consisting of two permea-
ters and  pressure  reservoir was  added
to  expedite  the  test  work  with
contaminated water  as a fluid.

     Operating pressures from 6 psi
to 20 psi  were used to accelerate the
tests.   Constant  pressures  were
maintained through  the use of an air
compressor attached to  the  fluid
reservoir.  The volume of fluid flows
measured  in a buret attached to each
test unit  (Figure  2), or by flowing
into a graduated cylinder through the
bottom drain valve.
Figure 2.  Test Permeater


                  • 1/4" TUBING FITTING
                                                                      POROUS
                                                                      STONES
                                           FLOW OUTLET *
                     200 MESH SCREEN
     Pretreatment of the soils with
the  additives  to  be tested  was
accomplished by direct addition  on a
weight  percent basis.  Approximately
lOOg of soil mixture was prepared for
each test.  Following the addition of
the  additives,  water was added as
required during  mixing to achieve a
medium to stiff consistency prior to
compression in the test mold.

     The unconsolidated soils were
prepared for testing  using parts from
a Harvard  Miniature  Compaction
Apparatus.  The tare weight  of  the
mold or  sleeve  from the permeater
plus a  200 mesh  screen and a 3.0 cm
porous  stone was obtained.  After
clamping the mold in  the mold holder,
the screen was placed in the  bottom
of the mold.  Approximately 30 cc of
the soil to be tested was  added and
gently tapped or  pressed  into  the
mold.  This amount of sample occupied
approximately one-half of the total
capacity of the  mold.  Water  was
added to maintain a saturated test
core during compression.  The porous
stone was then  placed on top of the
                                    292

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test sample in the mold and pressure
applied with the collar remover press.
This unit is equipped with  a spring
loaded  plunger with  a base plate
approximately 3.0  cm in  diameter.
The pressure was  applied by pushing
down on  the compression  rod.   In
total,  approximately 50 pounds  per
square inch was applied for a period
of 60 seconds.   After compressing the
sample  into the mold, the mold was
removed and  the final  weight of the
unit with the sample recorded.  Prior
to assembling the mold in the permea-
ter  the  height and  diameter of the
test sample  was  measured   and
recorded.

     Following  assembly of the  test
units,  water was  added to  the  fluid
reservoir.  The reservoir  was raised
to the  desired test pressure through
the use of an air compressor.  Prior
to beginning the tests, sufficient
water was added to each permeater to
displace the air trapped above  the
test core through the upper bleeder
valve.  Once the test unit was filled
with water,  the tests were  begun by
measuring the  flow through the  core
at various intervals of time.

     The  organic  permeability  tests
were also prepared  as described above.
Following measurement of  the  water
permeability,  the  inlet line at the
top of each unit was disconnected and
excess water above  the test cores
removed  (approximately  25 ml).
Approximately 25 ml  of chlorinated
hydrocarbon waste  was then added
through the inlet  opening at the top
of each  test  unit.   The water  line
was then reconnected  and   the  test
resumed  by  measuring the  flow of
water or organics at  various  time
intervals.  Following passage of the
organic wastes through the test  core,
the tests were continued to measure
the permeability of water through the
test core after exposure or contract
with the organic waste.
Soils Tested

     Various  soils were tested for
water  and/or  organic permeability
during the course of  the study.   Some
of these soils were  samples  taken
from specific  stratas encountered
during the core borings.  Some were
composite mixtures of soil represen-
tative of the overall stratas  that
would  be encountered  in an excavation
in the area.  These  included  soils
free from organic contamination and
those which are currently contami-
nated  in the  proposed slurry trench
area.

     Several  samples of  different
types of  uncontaminated soil  stratas
found  in the  are*. ^w" *« a  depth or
55 to  60 feet were  evaluated for
water  permeability characteristics.
Jhe  data were used  to confirm the
accuracy of the special test method
used  throughout  the study  and to
develop background data for hydraulic
flow in this area.

     In addition to the above, a com-
posite mixture of  uncontaminated
soils was prepared in proportion to
the soils that would be encountered
in the proposed slurry trench  area.
According to core borings the percen-
tage of various types of  soils  down
to a depth of 64 feet are presented
on Table 3.

    TABLE 3. COMPOSITION OF SOIL
   MIXTURE A (UNCONTAMINATED SOIL)

SoilDescription & Depth   Percentage

Fine to medium tan
   silty clayey sand
   (0-16)                    25.0%
Firm light gray and
   brown  silty clay
   (16-19)                    3.7%
Soft to very soft
   black organic clay
   (19-23)                    6.2%
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         TABLE 3 CONTINUED
Light gray fine to
   medium sand
   (23-59)
Stiff light gray
   and tan clay
   (59-63)
56.5%
 5.5%
     A mixture of  these types  of
soils was prepared from samples  taken
previously from the core borings.
This composite sample, referred  to  as
"Soil  Mixture A"  during the study,
was tested for water permeability
both with and without the addition  of
bentonite sealants.

     A contaminated soil mixture,
referred  throughout the study  as
"Soil Mixture B",  was also prepared
from  samples taken  from the  core
borings in the area of the proposed
slurry  trench.  This  mixture was
prepared  by taking  equal  portions
from samples taken  every two  feet
during the drilling operations. The
composition of soil  mixture  B  is
shown on Table 4.

    TABLE 4. COMPOSITION OF SOIL
    MIXTURE B (CONTAMINATED SOIL)

SoilDescription & Depth   Percentage
Tan silty clayey sand
   0-12
Tan and dark gray
   sandy (12-16)
Dark gray to black
   silty organic clay
   (16-20)
Silty, sandy clay
   (20-24)
Tan fine to medium
  sand (24-60)
Stiff gray and tan
   clay (60-62)

Fluids Tested
20.8%

 6.9%


 6.9%

 6.9%

55.2%

 3.4%
     Four  different fluids were
utilized during the investigation.
These included uncontaminated ground
water, contaminated  ground water.,
ground water which was saturated with
chlorinated hydrocarbon wastes  in  the
laboratory,  and  concentrated
chlori-nated hydrocarbon wastes.

     Two five  gallon containers of
contaminated water from the  area  were
contained for testing.  An analysis
of  this  water  was previously
presented in Table  2.  This water
sample was used throughout most  of
the test work and is referred to as
water in  the  balance  of  the report.
The water is of a quality  that could
be  expected to flow through  the
proposed slurry  trench.

     The concentrated chlorinated
hydrocarbon wastes used throughout
the investigation was a sample of API
separator organic waste  from  the
plant.  Although the exact composi-
tion of  this material  was  not
determined, it is believed that  this
is similar  in  composition to  the
waste materials processed  in earthen
ponds in the past that was the  source
of the plume of contamination in the
area.

Additive Materials Tested

     Several  oil  additive  materials
were evaluated  during the  course of
the  investigation.   These  included
two bentonite materials and cement
flue dust.  Although other possible
additive materials are available,  the
scope of the project was limited to
the first material found to  provide a
successful barrier to the flow of the
organic waste.

     The  bentonite  materials used in
the  investigation  were Volclay
Bentonite 125 (BENT125)  and Volclay
Saline  Seal  100  (SS100).   These'
materials are manufactured  by  the
American Colloid Company, Skokie,
Illinois  60077.   Bentonite  125  is
specially formulated for use  in
                                    294

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slurry trench construction to reduce
the flow  of water.  Saline Seal 100
is specifically formulated for use
where the fluid to be  controlled
contains relatively  high  concen-
trations of  salts and/or  other
contaminates.

    The  cement flue  dust utilized
throughout the investigation is a by-
product manufactured  by  several
cement plants  located in  Houston and
Dallas,  Texas.  The  sample  of the
cement flue  dust tested was manu-
factured by  Gulf Coast Cement in
Houston.

PROBLEMS  ENCOUNTERED

    The  only problems  encountered
during this series of tests involved
the method  of testing. Since no
standard method was available for
testing the  permeability of  organic
constituents  to  slurry walls  a
modification of ASTM  D-2434-68 was
incorporated.

    The  first  problem involved the
density differences between water and
chlorinated  hydrocarbon  waste.  The
ASTM method calls for  flow from the
bottom to the top of the  sample cell.
However,  the  density of  the chlori-
nated  hydrocarbon  caused water, the
displacement  fluid,  to pass  by the
waste  material and  directly  through
the soil.  To  alleviate this problem
flow was introduced from the top of
the cell  to the bottom.

    The  chlorinated hydrocarbon was
introduced directly into the  sample
cell before  water  was  added from the
top, as  a driving fluid.   This
reduced  the  possibility of phase
separation  and allowed a  slug of
contaminants  to be  injected into the
soil mixture.

    The  other  problem involved the
consolidation of soil  into a  stable
form.   As fluid was passed through
the  soil  mixture,  mobile  particles
traveled to the confining screen  and
plugged the face of the sample cell,
restricting flow.  Porous stones were
used as supplements to the screen to
reduce  the amount of face plugging by
distributing mobile particles over a
broader area.  This eliminated  the
flow restriction  and allowed long
term testing.

RESULTS

On-Site Soil Permeabilities

     The  water  permeability  of
various uncontaminated soil  strata
found in the area was determined in
the laboratory using  the  modified
test method.  These  data are pre-
sented on Table 5.  When  compared
with the field permeability  data of
similar type soils in the area, these
data indicate the modified test
method, used throughout the investi-
gation,  produces  results that  are
comparable with  standard methods of
test  for  field  permeability
measurements.
    TABLE  5  - WATER  PERMEABILITY
       UNCONTAMINATED SOILS
         OF
     Core DepthJ

     3-5 feet
     5-7 feet
     20 - 22 feet
     50 - 52 feet
     62 - 63 feet
     Soil Mixture A
     0-63 feet
Permeability,
    cm/ sec

  5.0 x lO-5
  2.3 x 10-4
  9.0 x ID"5
   .0 x 10-3
     z
2
1.2
     ID'8
3.7 x ID'7
1.9 x 10-7
     Several  samples of contaminated
soil from  the borings  were  also
tested for  water permeability.  These
included strata of  soils encountered
at various  depths  plus a  mixture  of
soils found at various  depths in the
area of the proposed slurry trench.
The  data  from these tests  are
presented on Table 6.
                                    295

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     TABLE 6. WATER PERMEABILITY OF
         CONTAMINATED SOILS
     Core Depth

     0-12 feet
     12 to 25 feet*
     25 to 60 feet
     62 to 65 feet
     Soil Mix B
     0-62 feet

     * Zone  of highest
      of contamination
Permeability,
    cm/sec,

  5.0 x 10-5
  2.1 x 10-7
  4.4 x ID'3
  1.8 x ID'8
  2.4 x ID'6
  1.9 x lO-6

 concentration
     The  fi11 material  (0-12 ft)
above the contaminated area  had a
permeability of 5.0  x 10~5 cm/sec.  A
mixture of  soil  in the zone  of
highest contamination  (12 to  25 ft)
had  a  permeability of 2.1  x 10"'
cm/sec.  Contaminated fine to  medium
sand (25 to 60 ft)  had a permeability
of 4.4  x  10~3 cm/sec, or approxi-
mately  the same as  the uncontaminated
sand from the same strata.  A mixture
of contaminated and uncontaminated
soils throughout  a  depth  of 0  to 65
feet below the surface (Soil Mixture
B) had permeabilities of  1.9  x 10~6
cm/sec and 2.4 x  10~6  cm/sec. The
difference between the permeabilities
of the  contaminated soil mixture
(Soil Mixture B)  and the  uncontami-
nated soil  mixture (Soil Mixture A)
of  approximately one  order  of
magnitude is probably a result of the
contaminated soil mixture containing
a higher percentage  of  sand (60% vs
56%) plus a lower  percentage of  dense
clay (2.6% vs 5.5%).

     Permeabilities  to water and
organic  liquids were  also determined
on several  samples  of  contaminated
soils  as  shown on  Table 7.  The
permeability of  Soil  Mixture B to
organics was 2.4  x  10~5 cm/sec  as
compared  with an average  initial
water permeability of 2.7 x  10~6
cm/sec. The contaminated zone mixture
had a permeability to organics of 3.1
x 1Q-5 cm/sec as compared with  an
average initial  water permeability of
3.3 x  10~7 cm/sec.  It is interesting
to  note  that although the initial
permeabilities to water  of these two
soil mixtures differ by  a factor of
approximately 10,  the permeability to
organics was approximately the  same.
An attempt was also made to determine
the permeability to organics of the
stiff clay found at  a  depth of  60
feet below the surface. Although the
clay exhibited an initial permea-
bility of 1.8 x 10~8 cm/sec to  water
and continued to  flow  water through-
out the  test,  there  was no visible
flow of organic through the test  core
as experienced during the other soil
tests.

TABLE 7. PERMEABILITY OF CONTAMINATED
               SOILS

Soil Sample    Ml    £      M£

Mixture B      10~6   10~5   10~7
(0-62  feet)
Contaminzted   10~7   lO"5   10~7
(12-26 feet)
Base Clay      10-°    0     lO"8
(60-62 feet)

Evaluation ofBentonite  125  and
Saline Seal 100

    A series of water  permeability
tests were conducted on  samples  of
contaminated Soil Mixture  B  when
treated with from 1% to  6% Bentonite
125 or Saline Seal  100.  These  tests
were conducted to compare the  per-
formance of  the two  different
bentonite  materials  in  the presence
of the contaminants contained in the
on-site soil. The results from these
tests  are presented  graphically on
Figure 3.
                                    296

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Figure 3. Permeability to Water vs.
      Percent  Bentonite
   . r
   10
  - -•
 <10
 UJ
 2  .
 a.
    -8
   10
BENTONITE 125

BENTONITE SS100
          12345
          PERCENT BENTONITE
                        organics was observed.  The average
                        permeability to water was reduced
                        from approximately 2.7 x 10-° cm/sec
                        down to 7.9 x 10"' cm/sec with  the
                        addition of 16% Bentonite 125.  The
                        maximum permeability to organic  was
                        reduced from 2.4 x 10"5 cm/sec down
                        to approximately 1.3 x 10~6 cm/sec at
                        a 16% Bentonite 125 treatment level.
                        In most instances,  the permeability
                        to water  was shown  to be approxi-
                        mately  the same as it was immediately
                        following passage  of the organics
                        through the test  core.  A plot  of  the
                        permeabilities vs percent Bentonite
                        125 is  presented  in Figure 4.

                        Figure  4.  Permeability vs.  Percent
                               Bentonite  125
    The  data  from  these  tests  show
the addition of of bentonite  to  Soil
Mixture B  results in  a gradual
decrease  in  the permeability of the
soil to  water.  With 6%  bentonite,
the permeability was reduced  from
approximately 2 x  10~6  cm/sec to 3  x
ID'7 cm/sec. Very little  if any
difference was observed in the
performance of the Bentonite  125 and
the Saline Seal  100 with the  contami-
nated soil. However, Saline Seal 100
was selected  for use in  all  subse-
quent test  work due to  its reported
resistance to high  concentrations of
salts.
Permeab.11 ity of
Contaminated Sol1
Bentonite Treated
     A  series of  tests  were  run  to
determine the water  and  organic
permeability of  the  contaminated
in-place soils (Soil  Mixture B)  when
treated with up to 16% Bentonite 125
or Saline Seal 100.

     When  treated with increasing
amounts of Bentonite 125,  a propor-
tional decrease in the permeability
of  Soil  Mixture B  to water and
                          « 10

                          o  .,
                          > 10

                          i  •*
                          < 10
                          UJ
                          S  -,
                          .S 10
                             »s
                            10
                                                • WATER
                                                • ORGANIC
                                   4   6   8  10  12  14
                                    PERCENT BENTONITE 125
                                                      16
                             Treatment with increasing
                         amounts of Saline Seal 100 resulted
                         in similar reductions in the permea-
                         bilities.  To  water, the  average
                         permeability was reduced from 2.7 x
                         10"6 cm/sec down to  approximately 9.0
                         x  ID'9 cm/sec with 16% SS100.  The
                         maximum permeability to organics was
                         reduced from 2.4 x 10-5 cm/sec down
                         to approximately 1.1 x  ID'7 cm/sec at
                         the 16% treatment  level.  A  plot of
                         the permeabilities vs percent SS100
                         is presented in Figure  5.
                                    297

-------
 Figure 5.  Permeability vs. Saline
           Seal 100
          4  8  8  10  12 14
          PERCENT SALINE SEAL 100
16
    The data  from  these tests
indicate treatment of  a mixture of
in-place soils in the  area of the
proposed slurry  trench  would require
the addition of  a minimum of 12%
bentonite (Bentonite  125 or Saline
Seal 100) to achieve  a permeability
of  1  x 10-7  cm/sec  to  water.
Treat-ment  with  a minimum of 16%
bentonite (Saline Seal  100)  would be
required to achieve a  permeability of
approxi-  mately 1Q~7 cm/sec or  less
to  organics. Although limited  data
are available on a  16%  Bentonite 125
treated soil, Saline Seal 100 appears
to  be  slightly more  efficient in
reducing the permeability of the
organic.  At all treatment levels,
however, the permeability to organics
was shown  to  be  10  to 100  times
greater  than the permeability to
water.   A positive flow  of
concen-trated  organics through the
test cores was observed in all of the
tests  regardless of  the level of
treatment.

Cement Flue Dust/Bentonite Treated
loTT       ~~

     Several samples  of Soil Mixture
B treated with 6% and 12% Saline  Seal
100 plus 1% up to a  maximum  of 18%
cement flue  dust were evaluated.

     The addition of  increasing
amounts of cement flue  dust  to  the 6%
Saline Seal  100 treated  soil resulted
in a  relatively small but correspond-
ing increase in  the permeability of
the mixtures  to water.  The average
water  permeability  increased from
approximately 3.8 x  10~7 cm/sec with
no flue dust up  to  5.6  x 10~7  cm/sec
with  12% flue dust.  The addition of
flue dust  failed to reduce the
permeability of the mixtures  to
organics.  Permeabilities within the
range of  1.7  x 10'6 cm/sec to  1.9 x
10"5  cm/sec were  measured for
organics.  In all cases, the permea-
bility to organic was shown  to be
higher  than the permeability to water.
Essentially all  of the organic
charged during each test  was observed
to pass through  the test cores. The
results from these test  presented on
Figure  6.

Figure 6. Permeability  vs. Flue Dust
         (With 6% SS100 Treated Soil)
               10
              o  -e
              jf 10

              3  ->
              m 10
             Ul
             a.
               10
               10
                         ' WATER
                         k ORGANIC
                          6  8  10  12  14
                         PERCENT FLUE DUST
                             16
                 The  addition  of  increasing
            amounts of cement flue dust to the
            12%  Saline Seal  100  treated  soil
            resulted in a similar increase  in the
            permeability to water.  The average
            permeability to water  increased  from
            1.7  x 10~8 cm/sec with no flue dust
            up to 9.5  x 10~7 cm/sec with  18%  flue
            dust.   The addition  of cement  flue
            dust to the 12% SS100 treated  soil
            however had a  significant effect  on
            the  permeability to  organics  at
            concentrations  of  6% flue dust  or
            greater.   The results  are presented
            on Figure  7.
                                    298

-------
 Figure 7. Permeability vs.  Percent
          Flue Dust  (With  12% SS100
          Treated Soil  Mixture)
o
a>  -s
5 10

0  -«
>: 10
=!  -»
m 10
  10
• WATER
»ORGANIC
       2   4   6  8  10  12  14 16

            PERCENT FLUE DUST
     The addition  1% to 6% cement
flue dust to the  12% Saline Seal 100
treated soil had little if any effect
on the  permeability  to the organics.
Essentially all   of  the  organics
charged to the units were observed to
flow through the test cores.  Permea-
bilities in the range  of  1  x 1Q~7
cm/sec to  5 x 10"'  cm/sec were
measured  for water  and 5  x  10~6
cm/ sec  for the organic.

     Using concentrations  greater
than 6% flue dust mixed with  the 12%
Saline Seal 100 treated soil, the
addition of organics to the  system
ultimately resulted  in  a sharp
decrease  in permeability  with
ultimate  plugging of the core.
Similar results were obtained with
12% and 18% flue dust.  In most cases
a small  quantity of water (1 to  3 ml )
was observed to pass through the core
following addition  of the  organic.
This was followed by a sharp decrease
in permeability to less than 1 x 10~9
cm/sec with ultimate plugging of the
test core.

Conf 1 rmat i on Tests

     Several  tests  were conducted in
the laboratory to confirm the  initial
positive  test results on  the 12%
SS100/12% flue dust treated  soils.
Tests  were also run  to investigate
the effects of various  other factors
on the  efficiency  and long  term
stability  of these systems.  In
addition,  a  test was run to confirm
the initial  results  obtained  on  the
stiff clay that underlies the area.

Permeability of 12%  SS100/12% Flue
Dust Treated Soil
                       A  sample  of Soil Mixture B
                   treated with 12% SS100  and 12% flue
                   dust  was prepared and tested in
                   accordance with the standard proce-
                   dures  used  throughout the investiga-
                   tion. The resulting mixture exhibited
                   an average  permeability  of 6.1 x 10~'
                   cm/sec to water.  Upon  contact with
                   the organic  waste,  a  sharp  decrease
                   in permeability was observed that
                   ultimately resulted  in pluggin
                   (permeability  less than 1  x 10"
                   cm/sec)  of  the core following passage
                   of approximately 2.5 ml of water.

                   12%/12% Mixture with Contaminated
                   Water
                       A  sample  of Soil  Mixture B
                   treated with 12% flue dust  and 12%
                   Saline  Seal  100 was  prepared for
                   testing using  contaminated water for
                   hydration  of the mixture.  This test
                   core exhibited  an average  permea-
                   bility to  water of 8.1 x 10"' cm/sec.
                   Following addition of  organics to the
                   unit,  the  permeability increased to
                   approximately 1.1 x 10~6 cm/sec for
                   the next  5  ml  of  fluid  to  pass
                   through the core.    During  this
                   period, approximately 1.5 ml of the
                   25 ml of organic charged to the  unit
                   passed through  the core. Subsequent-
                   ly,  a sharp  decrease  in permeability
                   occurred with ultimate plugging and
                   no flow of  fluid through the core.

                   12% Flue  Dust/12% SS100 Time-Set
                   Compact fofT

                       A  sample  of Soil  Mixture B
                   treated with 12% flue dust  and 12%
                   Saline  Seal  100 was  prepared for
                                    299

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testing. In this test, the mold was
filled with contaminated water  and
allowed to cure over a period of 12
days prior  to  beginning the permea-
bility testing.  This core  exhibited
a permeability  of 5.2 x 10~?  to water.
Contact with the organics resulted in
a sharp  decrease in permeability  with
plugging  of   the  core  following
passage  of approximately 3 ml  water.
No flow of organic through the core
was observed during the test.

W a t e r  S t r i p p i n g  of Avail a b1e
Alkalinity

     Analysis  of the effluent water
from previous tests using cement  flue
dust indicated an increase in pH from
7.6 up to 12.0  could  be expected due
to leaching of the available alkali-
nity in the  flue  dust from  the
treated soil  mixture.  A  test was
therefore  begun to evaluate  the
long-term effects  of water  stripping
of the available alkalinity  from the
12%/12% system on  the efficiency of
the system  to  retard or prevent the
movement of phased organics.

     A  sample of Soil  Mixture B
treated with 12% flue dust and  12%
SS100 was prepared in accordance with
the standard procedure for  testing.
The  pH  of  the feed water and  the
effluent was 6.9 and 12.0,  respect-
ively at the  start  of the  test. A
gradual  decrease in  the pH of  the
effluent occurred  during the course
of the test.  After  three months,
7,300 ml of water  had passed through
the core and the pH  of the  effluent
had decreased  to 7.0.  At that time,
22 ml of organics were charged  to the
unit.

     The permeability of  the  test
core to water  remained relatively
constant at approximately  3  x  10~7
cm/sec during  the first 2,000 ml of
water to pass  through the core.  The
pH of the effluent at this point had
decreased to approximately  9.8   A
gradual  increase in  permeability  to
approximately 3  x  10~6  cm/sec
occurred during  passage  of  the next
5,300 ml  of water.   Following the
addition   of   the  organics,
permeabilities  within the  range  of
1.0 x ID-6  cm/sec  to 6.0  x 10-6
cm/sec were measured for the next  30
ml of fluid to pass through the core.
This flow consisted of approximately
20 ml of phased organics  of  10 ml  of
water.    Subsequently, the  flow
consisted  of  water free  from  phased
organics  at a  permeability  of 5  x
10~6 cm/sec  for  the balance of the
test.   The pH of the effluent water
at the end of the test was 6.9.

E f f e c t s  o f Con t am in at e d W at er on t h e
12%/12% Mixture

    A  sample  of Soil   Mixture  B
treated with 12% flue dust  and 12%
Saline  Seal 100 was prepared  in
accordance with   the  standard  pro-
cedure  for  testing.   Saturated
contaminated water prepared in the
laboratory were  used to determine the
permeability  to water.  Approximately
2,000 ml  of  contaminated water was
passed through the test core  prior  to
contact  with the concentrated organic
waste.   During this  period, the  pH
decreased from 11.9 to 8.3.

    An  average  permeability of 3.0 x
10~7 cm/sec was measured for  contami-
nated  water.   On contact  with concen-
trated organic,  a sharp  decrease  in
permeability was observed following
passage  of an additional 2.5 ml  of
water  down to approximately 1 x 10~9
cm/sec.   No  phases  organic passed
through the core  during the test.

Base Clay Permeability

    An  undisturbed sample  of the
stiff  gray base  clay that is found
throughout the area was  prepared for
long-term testing  for  water and
                                   300

-------
organic permeability.  The test  core
exhibited an average  permeability to
water of 4.9 x 10~9 cm/sec. Following
passage of 4.1  ml  of water  through
the core, 25 ml  of organic was added
to the  unit.  During the next 80  days
approximately 25 ml of  additional
water passed through the  test core
with  no visible organics  in  the
effluent.  An initial increase in
permeability to  approximately 1 x
10"^ cm/sec was measured immediately
after the organic was added, followed
by a decrease to within the range of
5 x ID'10 cm/sec  and 6 x  10~9 cm/sec
during  the balance of the test.

DISCUSSION

     The  permeability of concentrated
or phased chlorinated hydrocarbon
wastes through the type of soils
found above the stiff base  clay in
the  area  was  shown  to  be
substan-tially greater  than  the
permeability of water through the
same soils.  A mixture of soils  in the
zone of maximum contamination (12 to
25 feet below the surface)  in  the
area of  the  proposed slurry  trench
exhibited a permeability of 3.3 x
1Q~7 cm/sec to  water and  3.1  x  10~5
cm/sec to the concentrated  organic
waste.   A mixture  of soil found  from
the surface down  to a depth of 62
feet had a  permeability of 2.6 x  10~7
cm/sec  to water and 2.4  x 10"5  cm/sec
to organic.

     The  stiff gray and tan base  clay
that extends throughout the area
which was encountered  at  a  depth of
approximately 50 to 60 feet below the
surface in  the  area of the  proposed
slurry trench  was shown to be an
effective  barrier to the downward
migration of  the waste.   This stiff
clay was shown to have  a permeability
in the  range of 4.9 x 10~'  cm/sec and
1.8 x 10"°  cm/sec to water.  The  clay
was impermeable to the flow  of the
concentrated  or  phased  chlorinated
hydrocarbon.

     Treatment  of  the  in-place soils
to produce an effective slurry  trench
barrier to the migration of the
phased organic waste  was  shown  to  be
feasible using one or two different
compositions.  In-place contaminated
soils when  treated  with  16%  Saline
Seal  100 exhibited  a  permeability  of
approximately 9  x  10~9 cm/sec  to
water and  3 x 10-7  Cm/sec to the
concentrated organic.  In-place soils
treated with 12% cement flue  dust and
12%  Saline Seal 100 exhibited a
permeability of approximately 4 x
10"7 cm/sec to water but  was shown  to
be essentially impermeable to the
concentrated organic  waste.   On
contact with the organic,  a sharp
decrease in permeability  occurred and
ultimately  after  passage  of
approximately 1-2 ml  of  water, the
test  cores  plugged with  essentially
no further flow of water or organics.

     The 12% flue  dust/12% Saline
Seal  100 treated soil mixture was
shown to  have a  limited effective
life  time to prohibit or restrict the
flow of phasedorganics.  Water
flowing  through the  mixture permea-
bility in  the range of 3 x 10-7
cm/sec  to 4  x  10"6  cm/sec)  resulted
in stripping of alkaline  constituents
from the  system and subsequent
failure to restrict the  flow  of
phased organics.   According to the
test data available from  the contami-
nated water flow test and the long
term water stripping test failure
should occur following  passage  of
from 73  to 225 trench  volumes  of
water through the barrier.  Under
normal  conditions, the amount of time
required for this  volume  of  water  to
move through  the  slurry  wall  would
range from approximately 1000 to 3000
years.
                                   301

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REFERENCES

1.  Anderson,  D.  C., Brown, K.W. and
    Green,  J. Organic Leachate
    Effects on the Permeability of
    Clay Liners.  Remedial Response,
    p. 223.

2.  D'Appolonia, Davis Jo. April 1980.
    Soil  Bentonite Slurry  Trench
    Cutoffs.   Journal  of the
    Geotechnical  E n g inee r i n g
    Division"

3.  Daniel, Davie E., Foreman, David
    E. Effects  of Hydraulic Gradient
    and Method  of  Testing on  the
    Hydraulic Conductivity  of
    Com-pacted  Clay  to  Water,
    Methanol, and Heptane, University
    of Texas, Austin, TX.

4.  Hughes, John. September,  1975.
    Use of  Bentonite as a  Soil
    Sealant for  Leachate Control
    Sanitary Landfills.  Void ay Soil
    Laboratory E n g i n e er _i n g  Report.
    Data 280-E.

5.  Kugs,  Charles, Rogoshewski, Paul,
    Repa,  Edward.  Alternatives  to
    Ground  Water Pumping  for
    Controlling  Hazardous  Waste
    Leachates,  JRB Associates.

6.  Laboratory Soil  Testing.
    Engineer Manual  EM 1110-2-1906,
    Department of the Army, Corps of
    Engineers.

7.  Ryan, Christopher.  February 1977.
    Slurry Cut-Off Walls  Design
    Parameters and Final Properties
    an  Interim Report,  Technical
    Course Slurry Wall  Construction,
    Design,  Techniques,  and
    Procedures, Miami, Florida

8.  Slurry Cut-Off Walls Methods and
    Applications, Geo-Tec  '80,
    Chicago, Illinois, March, 1980.
      The  work  described in this  paper
      Protection Agency.  The contents
     9.   "Standard  Test  Method for
         Permeability of Granular Soils
         (Constant Head)"  ASTM D-2434-68
         (Reapproved 1974)

     10.  T e c h n i c a 1  C at a 1 o g  f g r S o i 1
         S e a 1 a n t s, S1u r r y Tr en c h i n g an d
         Sanitary  L andf 111 ,  American
        Colloid Company,.
     11. T s h e b o t ar i f f ,  Gregory
   P.
Earth
and
      Agency and no official endorsement should be inferred.
        Foundations Retaining  and
        Structures,  Seepage
        Capillarity, p. 316.

     About the Authors
     Ken E.  Davis  is president of Ken E.
     Davis Associates,  3121 San  Jacinto,
     Suite  102,  Houston, Texas 77004. He
     has extensive experience in the field
     of  injection well  systems  and
     groundwater  protection.  His  current
     activities  include  the study of
     shallow groundwater  contamination
     from industrial hazardous waste areas
     and the development  of plans to
     contain and  remove  the contamination.

         Marvin C. Herring is  a Senior
     Scientist  for  Ken  E.  Davis
     Associates, 3121  San Jacinto,  Suite
     102, Houston, Texas 77004.   For the
     past  5 years he has worked as a
     consultant to industry  in the design
     of new systems for the disposal of
     industrial  wastes  and remedial
     actions for improperly designed waste
     activities.

         Tom  Hosea is  the Laboratory
     Supervisor  for Ken E.  Davis
     Associates, 3121  San Jacinto,  Suite
     102, Houston,  Texas 77004.   He has
     considerable  experience in core flow
     testing design and operation and in
     analytical  chemistry.  His  current
     activities  include  laboratory and
     field  applications  chemistry and
     continued slurry wall research.

was  not funded by  the U.S. Environmental
do not necessarily reflect the views of the
                                   302

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                     ADVANCED SECURE LANDFILL DESIGN
                        Randolph W. Rakoczynski,  P.E.
                      Waste Resource Associates,  Inc.
                          Niagara Falls, NY  14305
                                 ABSTRACT

     Geologic and  hydrologic conditions play an important role in determin-
ing the suitability of a particular site for  creating a landfill.  Often-
times,  poor  sub—surface conditions  will  prohibit  use  of  certain  areas
forcing waste generators to transport their residuals great distances for
proper  handling.   The advanced  secure  landfill presented in  this  paper
allows  siting in  less  than optimal  geologic/hydrologic conditions without
adversely impacting the environment.  The  advanced  design relies  for its
basis on many of the design elements Incorporated into many of the conven-
tional  secure landfills being  operated  in the  nation today.   It expands
these conventional designs  by  introducing  innovative concepts such as dual
underdrains and an in—situ leachate treatment system  to insure groundwaters
cannot  become contaminated.   It  provides  an opportunity to  establish  a
landfill operation in a less than optimal setting without adversely impact-
ing environmental  quality.
INTRODUCTION AND PURPOSE

     Landfills  have  been used
historically  for disposing of  a
multitude of  different  types  of
chemical and industrial wastes.   As
the  volume of  waste  production
increased,  many  landfills  became
over-burdened.    The  appearance  of
many  new and  often  highly  toxic
constituents in these  wastes  com-
bined  with  landfill containment
failures due to  poor  design and/or
less  than optimal site  selection
led  to  public  outcry.  This public
outcry  continues  to  grow  as  more
and more locations that are seeping
contaminants into  our groundwaters
are identified.

     The  advanced secure  landfill
design  presented,  is  an attempt  to
stem  this growing tide of public
opposition  to  landfill  disposal  by
providing  a  technologically-defen-
sible  approach  toward  containing
hazardous wastes.   It is  a care-
fully engineered design which
provides various  back—up systems to
insure  that  possible  escape  of
leachate  will  not contaminate
groundwaters.

APPROACH

Conventional  Design  Elements

There  are  certain  conventional
design  elements  which have  been
developed and  are currently util-
ized by some of  the major regional
HWMF's  in the   nation.   These
conventional  design  elements  are
the cornerstone  and  basis  of  the
advanced  design  which was  formu-
lated .

Liners

The use of both natural and  synthe-
                                   303

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CO
o
            DRAINAQE SWALE
                                                                                                      c
KEY (USED TO HOLD LINER IN PLACE

  AND FOR CLOSURE 8EALINO WITH

  SYNTHETIC LINER IN CAP)
                        SECONDARY UNDERDRAM
                                        Z2>—'
                                                                FOUNDATION OR BAM

                                                         (IDENTIFIED BY BUB-SURFACE EXPLORATION)
                                                                                                                   MONrroniHO WELL
                                                                                                                               z.
                                                                                                                 <—- WATER TABLE
                                                     ADVANCED SECURE  LANDFILL. DESIGN


                                                            (CROSS-SECTIONAL VIEW)

-------
tic  lining  materials  are incorpor-
ated into this design.  The natural
materials used  are  clay-type  soils
which given proper moisture content
and  compaction  can  be installed  to
provide  a liner  with a. hydraulic
conductivity of 1 x 10   cm/sec  or
less.   In order  to insure proper
compaction  it  is  recommended  that
clay liners  be  installed in  6"
lifts.

     There are a variety of synthe-
tic lining materials placed over the
entire interior  surface of the
landfill  which  can  be  used  to
augment the containment provided  by
a  clay  liner.   Among  the materials
currently available are  PVC  (poly-
vinyl  chloride),  CPE  (chlorinated
polyethylene)  and HDPE (high density
polyethylene).   The types  of  waste
which are intended  to  be   disposed
of and the resistance  of the lining
material  to  the range of  constit-
uents in  those  wastes  will dictate
the best choice of synthetic liner.

     In testing the various synthe-
tic lining materials,  a leachate  of
the  treated  (chemically-fixed)
residues to  be  disposed of, would  be
used.   The  leachate  would be  an
alkaline aqueous solution with trace
levels  of various  organic  contami-
nants .

     The lining system as presented
is a  "laminate"  which uses a  com-
pacted  clay  lining as a base beneath
the synthetic  liner.  Overlying  the
synthetic liner  is  another clay
lining which serves a  two-fold
purpose of  providing   a  protective
cover for the synthetic material  in
addition  to   supplying  further
containment.
 Waste Segregation

     The landfill  cell design  pre-
 sented provides for  waste  segrega-
 tio by  establishing  individual
 subcells  or  "compartments",  within
 the  landfill  itself  for  various
 waste types.   There are five  sub-
 cells in  the design:

    -  amphoteric
    -  heavy metal
    - general
    - halogenated
    - toxic

     The  ability to separate these
generic  waste  types  from  one
another enables  various  cover
materials  to be  utilized to immobi-
lize many of  the  constituents  in
the  waste.   For instance,  in  the
amphoteric subcell, waste carbonate
tailings can be  either admixed  with
the  waste or  used  as intermediate
cover material to create a buffered
pH  environment  between  7  and  8
within the subcell.   At  these  pH
values,  pseudo—metaIs  such  as
arsenic  and  selenium and  metals
such as aluminum will  tend  to
remain insoluble and  less mobile.
Application  of  alkaline  cover
materials  such as  hydrate  lime
tailings  in  the  heavy  metals
subcell  will create an  alkaline
pH environment tending to  keep the
heavy metals  insoluble.

     Separating the  halogenated
organic wastes  from other organics
in the general subcell enhances the
long-term  biodegradability  of
wastes in the  general subcell,  as
does the  segregration  of  toxic
heavy  metal  containing  wastes.
Further,  those halogenated residues
where breakdown  has begun to occur
creating  corrosive conditions
can  be neutralized  with  alkaline
wastes to prevent the formation of
acidic leachate.
                                   305

-------
Toxic Subcell

     This  subcell uses  a double
synthetic liner  system.  The "lami-
nate" ,   clay-synthetic  liner-clay
system,  is overlain with  a second
synthetic liner  of  HDPE.   This
material has  the greatest universal
resistance  to the  halogenated
and/or  corrosive  waste types
anticipated to  be  handled  in  such
a  subcell.   Once  again the lining
of HDPE  is covered with a liner of
compacted  clay  for protection and
additional containment.
Innovative Design Elements

     There are features  of this
advanced   secure  landfill  design
which  are  innovative  and represent
definite  improvements  over  land-
fills  constructed  solely with  the
conventional design elements already
discussed.  Specifically, the use of
a  dual underdrain system and  an
in-situ  leachate   treatment  system
are innovative design  features which
make  this  advanced  secure landfill
superior  to  prior  conventional
designs.
Internal  Leachate Collection System  Double Underdrain System
     The upper  clay lining installed
in  each subcell  provides a  rela-
tively  impervious base.   Any  rain-
fall which accumulates  in  the
landfill  and  becomes  leachate
through contact with waste comes to
rest on this base.    The   internal
leachate  collection  system is  the
mechanism  established  to  withdraw
this leachate for processing before
it  is allowed to percolate signifi-
cantly  down  through  the initial
clay lining. The system is composed
of  a tile underdrain,  covered with
crushed  stone,   that   hydraulically
connects two  vertical monitoring
standpipes.   These  vertical  stand-
pipes  are  2'-3'  diameter concrete
sewer  pipes with  bell-ends  placed
one  atop another as vertical filling
of  the  landfill proceeds.   The
initial  section of  each stand-
pipe is  set in a concrete base and
perforated  around its  circumference
to  allow for  inflow of  leachate.
The perforated portion of  each
standpipe  is covered  with crushed
stone  which  acts as  a  filter to
prevent solids  inflow and  subse-
quent  plugging  of  the standpipe.
As  leachate accumulates  within a
standpipe,  it is removed  by pump or
vacuum truck for processing.
     Although  a  single underdrain
 system has  been  in prior  use in
 various  conventional  secure land-
 fill  designs, this is the first
 time a dual (primary and secondary)
 underdrain  system  has been  pro-
 posed.   The primary underdrain is
 located  below  the  synthetic liner
 and  actually  serves  as the  base
 for the  in-situ leachate treatment
 system.    It serves  as a  device
 to  both  monitor  the  integrity of
 the  synthetic  liner and also
 remove  treated  leachate should  a
 leak in the liner occur.

     The secondary  underdrain is
 located  at  the  bottom of  the
 excavation  beneath  the  compacted
 clay  liner which  is  below  the
 synthetic  liner.   It  allows  the
 integrity of  the clay  liner to be
monitored  while also enabling
 any elevated water table  levels
 to be withdrawn before infiltration
 into the clay  lining  and  possibly
 into  the landfill.   Fluctuating
 and/or seasonally  high  water table
 elevations  can be  managed by using
 the secondary underdrain.
                                  306

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 In-situ Leachate  Treatment  System
                                     PROBLEMS ENCOUNTERED
      This is  probably the  most
 unique  feature of  the  design  since
 it  has  not been  used  to  any extent
 in  any  other conventional  designs.

      It  relies on  straight  forward
 chemical/physical   principles
 associated  with  immobilizing  the
 constituents  in .the  waste  types
 disposed of in the various  subcells
 of the  landfill.   Beneath the
 synthetic  liner  in  each  subcell  is
 a fixed  bed of different porous
 media capable of   sequestering  or
 immobilizing  contaminants   associ-
 ated  with  the  leachate from  that

subcell.   For instance, beneath the
amphoteric subcell uniformly crushed
limestone is  placed while  granular
lime is used under  the heavy metals
subcell.   The metallic  cations which
might be present  in   the  leachate
from  the  heavy metals  subcell  are
precipitated  by the alkaline condi-
tions  and enmeshed in the lime.  The
heavy  metal-free  aqueous liquid can
then  be  withdrawn   via  the  primary
underdrain system.

     Beneath  the  halogenated,
general  and  toxic  subcells,  the
fixed  bed  of porous media  is com-
prised of granular activated carbon.
A bed depth of 3"  to  4" is suffic^-
ient  to  provide enough carbon  to
adsorb the  soluble,  high molecular
organic  contaminants in the leachate
in these subcells.   As long as this
activated  carbon  is exposed  to
continually increasing  concen-
trations  of  adsorbable  organics  in
the  leachate which  it contacts
(which should be  the case during any
post-closure  liner   failure/leachate
leakage),  it  will  function  effec-
tively.   Once again treated aqueous
liquid can  be withdrawn using  the
primary  underdrain system.
     In order  to determine  if the
advanced   secure  landfill  design
is  competitive  with conventional
designs,  an economic analysis  of
the cost  of  construction  of  both a
"shallow"  and   "deep"  landfill
for both  the advanced  and conven-
tional designs was undertaken.   The
"shallow"   landfill  has  a  depth  of
22.5 feet while  the  "deep" landfill
has  a depth of  47.5  feet.    An
additional variable,  the  location
of the landfill  with respect to the
existing  grade,   was also considered
in  the comparative  cost   analysis.
In  the situation where  100%  of the
landfill  is located above  grade,
the floor  of the  landfill  cell  is
actually  at  ground level.   In all
cases the size of the landfill  cell
considered was 500' x 500*  measured
along  the  top  of the  perimeter
berms.   This gives a maximum  dis-
posal  capacity of 147,200 cu.yds,.
for the   shallow landfill  and
260,000  cu.yds. for  the.deep.

FixedCosts

     There are  certain cost ele-
ments in both the  conventional and
advanced designs  which are  indepen-
dent of  the  depth ' below the grade
we  choose  to  locate the  landfill.
For  the   "shallow"  and  "deep"
conventional  and  advanced  landfills
these  elements   are  the  synthetic
liner and  compacted  clay  to  cover
the liner:

         Synthetic liner

"shallow"      275,000 sq.ft.
"deep"        325,000 sq.ft.
       Primary clay liner
"shallow"
 "deep"
21,000 cu.yds.
30,000 cu.yds.
                                   307

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                            Table 1:  Construction Volumes  ("Shallow" Landfill)

                                              in thousand cubic yards
CO
o
CO



Excavation
Perimeter Berras
Cover Material
Primary Clay Liner
Secondary Clay
Liner
Stockpile
(Shortfall)
Table




Excavation
Perimeter Beras
Cover Material
Primary Clay Liner
Secondary Clay
Liner
Stockpile
(Shortfall)
% Above Grade
0% 50%
Con. Adv. Con. Adv.
150.0 275.0 75.0 244.0
34.0
36.8 36.8
21.0 21.0
35.0 - 35.0

92.2 182.2 (16.8) 116.2

2; Construction Volumes ("Deep" Landfill)
in thousands of cubic yards
% Above Grade
0% 50%
Con. Adv. Con. Adv.
295.0 385.0 108.0 485.0
134.0
65.0 65.0
30.0 30.0
45.0 - 45.0

200.0 245.0 (121.0) 271


100%
Con . Adv .
150.0
120.0
36.8
21.0
35.0

(177.8) (62.8)




100%
Con . Adv .
232.0
508.0
65.0
30.0
45.0

(603.0) (416.0)


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Excavation
Perimeter Benns
Cover Material
Primary Clay
Synthetic Liner
Primary Under-
 drain
Secondary Clay
Secondary Under-
 draln

Total Cost:

Unit Cost:
(per cu.yd.)
                  Table 3:  Cost Comparison ("Shallow" Landfill)
                               in thousands of dollars

                                   % Above Grade
0% 50%
Con.
$375.0
—
— ,
$105.0
$165.0
*_«.
—
—
Adv.
$687.5
—
—
$105.0
$165.0
$850.0
$175.0
$65.0
Con.
$187.5
$85.0
$4.0
$105.0
$165.0
_—
_
—
Adv.
$610.0
$85.0
—
$105.0
$165.0 '
$850.0
$17.50
$65.0
100%
Con.
-
$900.00
$184.0
$210.0
$165.0
—
_
—
Adv.
$375.0
$195.0
$184.0
$105.0
$165.0
$850.0
$175.0
$65.0
  $645.0  $2,047.5

   $5.84    $18.55
  $626.5 $2,055.0

   $5.67   $18.61
$1,459.0  $2,114.0

  $13.22    $19.15
Excavation
Perimeter Benns
Cover Material
Primary Clay
Synthetic Liner
Primary Under-
 drain
Secondary Clay
Secondary Under-
 drain

Total Cost:

Unit Cost:
(per cu.yd.)
                  Table 4:  Cost Comparison ("Deep" Landfill)
                               in thousands of dollars
                                   7, Above Grade
        0%
    Con.     Adv.
  $737.5    $962.5
$1,082.5  $2,132.5

   $5.55    $10.94
        50%
    Con.    Adv.
  $270.0 $1,212.5
  $612.5   $335.0
  $325.0     —
$1,552.5 $2,717.5

   $7.96   $13.94
      100%
   Con.     Adv.
           $580.0
$3,810.0 $2,632.5
  $325.0   $325.0
$150.0
$195.0
—
$150.0
$195.0
$550.0
$225.0
$50.0
$150.0
$195.0
—
$150.0
$195.0
$550.0
$225.0
$50.0
$300.0
$195.0
—
$150.0
$195.0
$550.0
$225.0
$50.0
$4,630.0 $4,707.5

  $23.74   $24.14
                                      309

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Variable Costs

     There  are  various  site-spec-
ific  factors which will  have a
dramatic impact on the actual costs
associated with the construction of
a  landfill  facility using  either
the conventional or advanced secure
landfill design.

     There  is a distinct possibil-
ity  that  regenerated  activated
carbon which is no longer suitable
for conventional wastewater treat-
ment  applications can  be  used  in
the  in-situ treatment  system,
drastically   reducing  the  overall
capital cost of  the advanced secure
landfill facility.

     The tables  which  follow
related  the  construction  volumes
and  associated  costs  for  the
various scenarios considered.
     It is understood that construc-
tion costs may  vary  widely between
different  geographic  regions and
many  site-specific factors  will
influence  actual  construction
costs. The cost comparison presented
is not  meant  to  establish  an abso-
lute  capital cost estimate for
constructing  a  facility  since
specific costs associated with site
acquisition/  development,  hydro-
geological   investigation,  permitt-
ing,  monitoring and  ancillary
equipment/structures  were  not
included.    The following unit
costs were  used  to  enable a  valid
comparison  to be  drawn  between  the
two  designs  and to evaluate  the
impact the degree below grade would
have on a proposed design.
 Unit Costs

 Excavation (assuming   $2.50/cu.yd.
 a  uniform deposit at
 less than saturated
 conditions with a
 stable sub—base)

 Perimeter Berms:
 -obtain off-site soil  $7.50/cu.yd.
 and compact
 -compact on-site       $2.50/cu.yd.
 soil

 Compacted Clay
 -obtain off-site      $10.00/cu.yd.
 clay and compact
 -compaction on-site    $5.00/cu.yd.
 clay
 Cover Material
 -obtain off-site       $5.00/cu.yd.

 Results

     The  comparative  cost  analysis
 bears  out the  fact for all  cases
 with  the  exception of a "deep"
 landfill  located   entirely  above
 grade,   the  conventional design  is
 considerably less expensive than the
 advanced  design.   Although the
 conventional  design presents  a

 less costly alternative in landfill
 construction,  the costs associated
 with remedial  action  necessary  to
 rectify  groundwater  contamination
 that might occur with  this design
 can be several  multiples  of  the
 total  construction  cost  listed.
 The magnitude  of  these remedial
 action  costs  and  the  long  term
 liability it represents to facility
owners  and  to  the  government  (if
 remedial action is  required during
or  following  the  post closure
 period bears out  the  economic
 feasibility  of the additional
 expense associated with the  use of
 the advanced design.
                                   310

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     Additionally  economic  feasi-
bility  for  the  advanced  secure
landfill design can be demonstrated
if  the  distances  from  the  source
of waste generation to a permitted
facility  using  a conventional
design are considered.  If one-way
transportation charges of $3.75 per
mile for a bulk, 20 cu.yd. shipment
of waste are assumed,  the following
table  shows   the  "breakeven"  dis-
tances  in  miles.   If the distance
between source of generation and a
permitted landfill facility employ-
ing  the conventional design are
greater than those  listed,  the
advanced secure landfill design can
be  justified  on  the  basis  of
savings in  transportation charges.

"Breakeven  Point Transportation
 Distances (one-way miles)

          % Above  Grade
            0%    50%    100%
"Shallow"   68    69

"Deep"      29    32
32
             Acknowledgements

                  The advanced  secure landfill
             design presented  is the property of
             Environmental  Design,  Inc.  (Hwy.l,
             Jupiter, FL 33458)  and is protected
             under  U.S. Patent No. 4,430,021.
             Waste  Resource  Associates,  Inc.
             acted  as technical consultant  to
             Environmental  Design,  Inc.  in  the
             development  of   the  design  and
             Randolph W. Rakoczynski is  a  co-
                          the  design  along with
                          Wagner and  Mr. Harold
                           Flannery & Esz, Inc.
                          OH)  have had consider-
             able experience  in  the construction
             of  secure  landfill facilities.
inventor of
Mr. Louis E.
F. Flannery.
(Cincinnati,
     Mr.  Gary W.  Catlin,  Vice
President  of   SLC  Consultants/Con-
structors,  Inc., an individual with
considerable actual field experience
in  secure  landfill  construction,
assisted  in establishing  the  unit
costs used  in  the  cost comparison.

     Currently,  SolidTek  Systems,
Inc. is a licensee of Environmental
Design,  Inc. for the advanced secure
landfill in  the states of Georgia
and Pennsylvania.
                               Disclaimer

                 The work described in this paper was
                 not funded by  the U.S. Environmental
                 Protection Agency.  The contents do
                 not necessarily  reflect the views of
                 the Agency and no official endorse-
                 ment should be inferred.

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                  DE-GASIFICATION OF EXISTING LANDFILLS
           Paul C. Rizzo
           Paul C. Rizzo Associates, Inc
           Post Office Box 17180
           Pittsburgh, PA  15235

                                ABSTRACT
      Carl M. Rizzo
      R & R Petroleum, Inc.
      206 Rodi Road
      Pittsburgh, PA  15235
    De-gasification programs at waste landfills are undertaken for two
purposes; resource recovery and landfill safety.  This paper will
describe a specific methodology to address safety problems posed by
pressurized toxic gases at an uncontrolled waste disposal site.  A
conceptual design for a system to both investigate and relieve
pressurized, and possibly toxic, gas problems is presented.  The
hypothetical case is for a landfill located in a populated area in which
"zero release" of gases Is a project constraint.
INTRODUCTION AND PURPOSE

    This paper deals with a
subset of sites that for one
reason or another have (a) a
combination of chemical con-
stituents capable of producing
toxic and/or volatile gases
such as hydrogen sulfide,
methane, chlorine, etc.; and
(b) a geometrical config-
uration that would allow for
the build up of pressure.
Buried drums are the first
such configuration that might
come to mind.  Other typical
geometries are illustrated in
Figures 1 and 2 where a "hard"
crust forms a buried cap over
a. zone of waste materials
capable of producing a gas.
The crust, being relatively
Impermeable and of relatively
high shear strength, allows
for the build up of gas
pressure.  The gases may build
up in pockets or in a
relatively uniform zone,
depending on the homogeneity
and thickness of the crust,
and the nature and quantity of
the gas-producing waste
material.
    Upon penetration of a
buried drum or a crust by a
conventional geotechnical
drilling rig, or by the unwary
construction equipment
operator during cleanup of the
waste, the gas can be released
in an uncontrolled manner,
thus endangering the drillers,
construction equipment
operators, and possibly the
public as well.  Of course, if
the concentrations are high
enough and the pressure and/or
quantity is high enough, the
problem could have relatively
serious implications.

    In the oil and gas
industry, the handling of
unknown quantities of natural
gas and occasionally hydrogen
sulfide are practical problems
encountered in the normal
course of business and
operations.  These gas "kicks"
are handled routinely, and in
the case of hydrogen sulfide,
there are established safety
protocols for dealing with the
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toxic nature of the gas.  This
industry has built up a wealth
of experience, equipment,
monitoring systems and safety
procedures.  It Is the purpose
of this paper to illustrate
how the experience and back-
ground of the oil and gas
industry can be used in
conjunction with conventional
geotechnical Investigation
techniques to Investigate,
relieve, or vent toxic gases
from a shallow landfill In a
safe controlled manner—either
on an emergency basis or as
part of a remedial action
program.

APPROACH

    The installation of toxic
gas venting wells at a site
such as shown In Figures 1
and/or 2, requires a
combination of highly
specialized skills that are
not easily combined.  For
example, the depth is rather
shallow, generally less than
50 feetj this is quite
suitable for a typical
geotechnical drilling rig.
However, the presence of a
toxic or volatile gas such as
chlorine, hydrogen sulftde or
methane at unknown pressure
and concentration, requires
the use of oil field tech-
niques including extra heavy
mud, possibly a blowout
preventer (BOP), some type of
mud-gas separator, shaker, and
a degasser such as shown In
Figure 3.  The degasser
removes the gas from the
drilling mud and allows for
transmission to a treatment
unit such as a scrubber, or in
limited cases to a flaring
system.  The extra heavy mud
and possible BOP are both
required to assure a margin of
safety consistent with the
margins used In other parts of
an EPA-sponsored cleanup.  The
heavy mud and the BOP require
an oil-field type rig because
of the need to use larger
diameter drill pipe and
casing, and heavy duty mud
pumps.  BOP's are not always
readily available for small
diameter drill pipe; and
furthermore, the use of extra
heavy mud (possibly 20 pounds
per gallon) requires larger
diameter drill pipe and
adequate pump capacity.  These
are key factors in the
technique which may preclude
the use of a conventional
geotechnical drilling rig.

    The handling of the toxic
gas requires a closed-mud
system, also common to an oil-
field driller but not to the
geotechnical driller.  As
mentioned above, the system
might Include a shaker,
possibly a mud/gas separator,
and a degasser to allow for
removal of the gas and
transmission to some sort of
treatment unit such as a
scrubber.  Mud tanks are used
for mixing and handling the
mud as opposed to mud pits.
Here Is an example where the
experience of the geotechnical
driller comes Into play.  The
oil and gas driller Is used to
handling large quantities of
mud, and consequently, the use
of mud pits Is the common
practice.  Shallow drilling
for waste sites requires
relatively small quantities of
mud; and, therefore, mud
tanks—the type that a
geotechnical driller might use
In a confined environment are
more appropriate.
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    It is also noted in Figure 3
that we show an emergency
"kill" line similar to that
used for oil and gas drilling.
This line allows for the
addition of drilling mud under
higher pressure should a fire
or an unusual gas"kick" occur
during drilling or development
of the well.  We also show the
mud pump as being separated
from the drill rig; however,
the mud pump may very well be
part of the drill rig in many
applications.

TYPICAL INSTALLATION SEQUENCE

    Generally speaking, the
operation begins with the
mobilization of a crew and
equipment to the site.  The
field crew normally would have
a project safety review before
leaving the yard, including
physical examinations and a
review of the safety equipment
contemplated for use at the
site.  The crew normally con-
sists of five experienced
members (superintendent, tool
pusher/driller, driller/helper,
power swivel operator, and
well-site health and safety
officer).  Me mention a power
swivel operator as being a
member of the crew because an
oil well service rig equipped
with a power swivel as opposed
to a rotary mud rig is often
the preferred type of equip-
ment for this application.
The crew is usually programmed
to work an extended single
shift as work during daylight
hours is preferred; however,
in many applications, round-
the-clock operations are
necessary.  This is the norm
in the oil and gas industry
and does not present unusual
operating problems.
    Along with the service rig
and power swivel, a mud-mixing
system including a shaker and
degasser are mobilized to the
site.  Material such as
casing, drilling mud, cement,
and so forth are ordered in
quantities sufficient to
complete a group of wells with
the mud coming from a supplier
retained to specify the mud
program including mud-testing
procedures.  Cementing is
generally delegated to a
specialty oil field cementing
service company as this
requires special equipment not
normally operated by the
drilling crew.

    The detailed technique for
the venting well installation
will vary from site to site,
depending on particular
conditions.  The following
steps would apply to a site
having a geometry as shown in
Figures 1 and 2 where the
crust might be about 20 feet
down from the surface and
about two feet thick;

1.  Construct an earth-
    drilling pad to support
    the drilling rig.
    Generally speaking, the
    surface will be relatively
    soft, too soft to support
    the drilling rig; and
    therefore, a drilling pad
    will have to be
    constructed with earth-
    moving equipment.  In
    Figure 4 we show the use
    of geotextile material
    between the surface of the
    landfill and the earth-
    drilling pad.

2.  Rotary drill an open hole
    with heavy mud to a point
    within about 4 feet of the
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crust.  Install steel
surface casing and cement
(the first stage) to
surface using a specialty
cementing service sub-
contractor.  Casing Is
sized to permit the
circulation of extra heavy
mud, which is critical in
subsequent steps in main-
taining a closed system to
mitigate random or unpre-
dicted gas releases
(Figure 4).

Connect the drilling tree
(with blowout preventer,
degasser and drill line
connections) to casing and
re-insert rotary drill
tools (Figure 5).

Advance the hole using the
rotary techniques through
crust to a point about 4
feet below "crust."  Use
extra heavy mud and a mud
program designed by the
supplier.  Circulate the
mud through the shaker and
degasser which is in turn
connected to the scrubber
(Figure 6).  It is noted
that during the drilling
process the circulatory
mud might bring waste
liquids, such as organic
solvents, from "old" drums
to the surface.

If no gas kick occurs or
after a. kick is fully
relieved, trip out the
drilling tools and install
production casing with
closure valve through the
surface casing.  The
bottom four feet of the
production casing will be
slotted or screened.
Using a combination of
external and internal
    packers such as a for-
    mation packer collar
    and/or baffle plates set
    in at the crust,.remove
    the mud above the packers
    and cement (second stage)
    the production casing to
    the surface (Figure 7).

6.  Re-Install a drilling tree
    over main closure valve.
    Trip in the small diameter
    drilling tools.  Refill
    production casing with
    mud.  Drill out the
    internal packer or knock
    out baffle plates.

7.  Dilute the mud mix by
    washing through tools
    until mud is practically
    water.  "Develop" the well
    to extent practical.

8.  Trip out the drilling
    tools through BOP and
    stripper.  Close the main
    valve on the production
    casing.  Remove the
    drilling tree and install
    production tree (Figure
    8).

    At this point, the well is
available for venting of the
gas and its subsequent
treatment at a scrubber or
treatment unit.

HEALTH AND SAFETY

    The members of the
drilling crew must be
thoroughly knowledgeable of
the personal protection
procedures dictated by the oil
and gas industry and hazardous
waste emergency response
health and safety programs.
Normally this type of project
will employ EPA "Level B"
protection with some minor
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modifications  to suit  field
conditions.  For the example
shown in this  paper where  the
toxic gas is generated in  the
waste beneath  the crust, the
Level B protection would be
employed when  the drill tools
are re-inserted into the
cemented surface casing.
Level B is not necessary for
work above the crust because
any gas encountered above  the
crust would be relatively  low
pressure and would be counter-
acted by the heavy mud with
adequate margin.

    Monitoring systems are set
up around the  rig and around
the site fence line.  For  a
hydrogen sulfide venting
project, we would employ a
battery-operated monitoring
system sensitive to one PPM.
This would be operated during
drilling operations after  the
surface casing is installed if
we are reasonably sure that
the gas content of the waste
material above the crust is
minimal.  Alternately, one
might utilize an organic
monitor and/or an explosive
meter, or other appropriate
real-time monitoring
equipment.

SUMMARY

    Remedial action programs
and emergency response pro-
grams occasionally dictate the
need for the relief, handling
and treatment of pressurized
toxic or volatile gases in
relatively shallow lagoons
and/or landfills.  This paper
presents a technique which
combines the knowledge and
experience of the oil and gas
industry with  that of the
conventional shallow geo-
technical driller.  This
procedure results in an
effective and safe means of
installing relief wells with-
out undue risk to drillers and
the general public.  The key
factors in the operation
include the use of an extra
heavy drilling mud, a closed
mud system, and the possible
use of a blowout preventer.
The techniques used herein are
not new, and in some cases,
would be viewed as relatively
conservative applications of
equipment that are used for
much more dangerous situations
such as those encountered in
oil and gas drilling.  The
application in such shallow
deposits as encountered in
lagoons and landfills, how-
ever, does require some mod-
ification because of the shal-
low nature of the deposits.

ABOUT THE AUTHORS

Dr. Paul C. Rizzo
    Dr. Rizzo is founder and
President of Paul C. Rizzo
Associates, Inc., a consulting
organization based in
Pittsburgh that works inter-
nationally on the solution and
cleanup of waste problems—
both nuclear and chemical
hazardous waste.  Dr. Rizzo
received his Doctorate from
Carnegie Mellon University,
has published numerous papers,
and has served on a number of
international panels and
committees dealing with
environmental issues.

Mr. Carl M. Rizzo
    Mr. Rizzo is co-founder
and President of R & R
Petroleum, Inc., a Pittsburgh
based independent oil and gas
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producer working in the
Appalachian Basin of the
United States.  Mr. Rizzo has
designed, supervised, and
operated oil and gas drilling
programs and production
systems for wells as deep as
5,000 feet—the normal depth
in Appalachia.  Mr. Rizzo
holds a Masters degree from
the University of Pittsburgh
and has worked both onshore
and offshore on shallow
drilling projects.
                               Disclaimer

                 The  work  described  1n  this  paper was
                 not  funded by  the U.S.  Environmental
                 Protection Agency.   The contents do
                 not  necessarily  reflect the views of
                 the  Agency and no official  endorse-
                 ment should be Inferred.
                                   317

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                FACTORS AFFECTING STABILIZATION/SOLIDIFICATION
                              OF HAZARDOUS WASTE
                        Jerry N. Jones, R. Mark Bricka,
                    Tommy E, Myers, and Douglas W. Thompson
               U. S. Army Engineer Waterways Experiment Station
                           Vicksburg, MS  39180-0631

                                   ABSTRACT

     The stabilization/solidification of toxic wastes involves a series of
chemical and/or physical treatment procedures.  The waste is normally treated
so as to complex or bind the toxic elements in a stable, insoluble form or to
entrap the waste material in a crystalline matrix.  A hazardous waste may con-
tain many constituents that could interfere with the binding process.  This
recently initiated project is concerned with identifying possible interfering
mechanisms between particular compounds and waste binding systems.

     A synthetic sludge was produced containing parts per million concentra-
tions of cadmium, chromium, mercury and nickel.  The sludge is mixed with
increasing concentrations of interfering compounds and then with selected
waste binders.  Various waste mixtures will be evaluated to determine the par-
ticular interfering effects on stabilization/ solidification processes.  This
paper provides an interim report on the progress of the study.
INTRODUCTION

     The Environmental Protection
Agency (EPA) is responsible for eval-
uating the suitability of hazardous
waste for land disposal and for the
examination of hazardous waste de-
listing petitions under the Resource
Conservation and Recovery Act (RCRA)
regulations.  A thorough understand-
ing of the potential behavior of
stabilized/solidified waste is neces-
sary to make judgements as to the
effectiveness of contaminant contain-
ment.  There are several methods
available for the stabilization/
solidification (S/S) of many hazard-
ous wastes.  The complexity of some
wastes is such that some of the chem-
ical components of the waste may in-
terfere with the proposed S/S process
and cause an undesired phenomenon
(e.g. flash set, set retardation,
spalling, etc.).  There is a lack of
quantitative data concerning the
effects of these interfering compo-
nents upon the particular S/S pro-
cess.  A study of the factors
affecting S/S of hazardous waste is
designed to help fill that data void.

Background

     Experience from the cement and
asphalt industries, as well as radi-
oactive waste solidification, has
demonstrated that small amounts of
some compounds can seriously reduce
the strength and containment charac-
teristics of binder/waste mixes used
in S/S technologies.  The common
binding materials in waste S/S sys-
tems are derived from industrial
cement and asphalt materials and some
data are available on the effects of
impurities on strength, durability,
and permeability of structural cement
mixtures.  The cement industries have
had to specify the types of cement,
aggregate, and accelerators or re-
tarders that will be permitted in
Portland concrete specifically
because additives affect performance.
Radioactive waste processors have had
to develop limits for particular com-
ponents that reduce the effectiveness
of S/S of their wastes.  In some
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cases these interfering materials can
produce set retardation so that hard-
ening does not occur.  In other
cases, a waste constituent may cause
a flash set or flash hardening so
that effective mixing of the waste
and binder cannot occur.  Some waste
constituents can react to cause
swelling or disintegration of the
solidified mass after setting.  The
effects of these interfering materi-
als are often disproportionate to the
amounts present in the waste.

     Research that clarifies the re-
lationship between the composition of
the waste and performance of the
binder can greatly help in evaluating
the hazards of the materials.  For
example, minor organic components in
a waste stream can significantly
retard the cementing reaction, but
these specific materials can be lim-
ited in a processor's treatment per-
mit to assure that binding reactions
occur, and that waste containment is
not compromised.  Similarly other
deleterious compounds that cause
flash sets or expansion reactions can
be excluded where reactive binders
are proposed.

     When waste is placed for final
disposal, there is always a possibil-
ity of the waste being unearthed by
erosion or later excavation.  The
impact of stabilized/solidified mate-
rial on its surroundings after expo-
sure can be significant.  The effect
that interfering substances have on
the durability of stabilized/solidi-
fied waste is a question of paramount
importance.

PURPOSE

     The purpose of this study is to
develop technical background data on
the compatibility of critical waste
constituents with various waste bind-
ing agents (portland cement, portland
cement with additives, lime-pozzolan
cement, gypsum cement).  Specific
supporting objectives are as follows:
     (1)  Perform physical tests and
chemical leaching tests on waste/
binder mixtures.

     (2)  Investigate the relation-
ship between the amount of interfer-
ing substance and the significance of
the interference to waste S/S
reactions.

     (3)  Evaluate the durability of
specific waste/binder mixtures to
long-term outdoor weathering.

     (4)  Participate in the joint
Alberta Environmental Center/Envi-
ronment Canada/USEPA/Industry project
to investigate test methods for use
in evaluating solid wastes.

This paper will report on the results
and progress made as of May 1985.

APPROACH

     The study is being conducted in
two phases (Figure 1).  The first >
phase (Phase I) was completed in
December 1984 and included the fol-
lowing tasks:

     (1)  Conduct a literature search
and report on potential factors af-
fecting solidification processing of
hazardous industrial and radioactive
wastes.

     (2)  Selection of four waste/
binder systems and ten potential
interference materials.

     (3)  Formulation and processing
of stock synthetic waste to be used
in preparation of test specimens.

     (4)  Screening for various
waste—to—binder ratios.

     Phase II of the study will be
conducted over a 24-36 month period.
Samples of the selected waste/binder
system and interfering materials will
be tested and evaluated by the U. S.
Army Engineer Waterways Experiment
                                      321

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                                        (PHASE I)
                    REVIEW LITERATURE •
                                                 SELECT WASTE/BINDER SYSTEMS
                    FORMULATE STOCK
                    SYNTHETIC WASTE
                                                 SELECT INTERFERENCES
                               SCREEN FOR WASTE-TO-BINDER RATIOS
                                       (PHASE II)
                       PREPARE SAMPLES
                    FOR TESTING AND EVALUATION
                    WES TESTING PROGRAM

                        LABORATORY TESTING

                        FIELD EXPOSURE TESTING
      SPLITS TO ENVIRONMENT
  CANADA FOR COOPERATIVE TESTING
                    REPORTING OF RESULTS
                      Figure  1.   Simplified Study Approach,
Station  (WES).   Samples of stabi-
lized/solidified waste will be  tested
for various  physical properties and
chemical  leaching quality.

PROBLEMS  ENCOUNTERED

     The  first  experimental diffi-
culty encountered in this study was
the requirement to produce a  syn-
thetic waste sludge that was  both
reproducible and had stable physical
and chemical characteristics.   A
hydroxide metal sludge filter cake
has been  formulated that meets  this
study requirement.  The cake  is pre-
pared by  taking a solution of metal
salts, precipitating the metals with
lime, and then  vacuum filtering to
produce a consistent filter cake of
approximately 25 percent solid
content.
RESULTS

Literature  Survey

     A review of the literature  on
solidification processing of waste
showed that published information is
limited which specifically relates to
organic and inorganic interference
phenomena in waste binding processes.
Since most  waste S/S systems incor-
porate various cement configurations,
some inferences may be made between
admixtures  in cement chemistry and
certain Interferences in S/S
processes.

Additives In Portland CementConcrete

     In the production of portland
cement concrete, the use of chemical
additives to control setting times,
to reduce water requirements,  to en-
train air,  and to create many  other
beneficial  effects is common prac-
tice.  The  changes in properties
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affected by additives are assumed to
reflect fundamental changes in the
hydration products, especially the
crystalline calcium silicate hydrate.
The chemical and physical development
of concrete is complicated.  The in-
terfering effects of waste constitu-
ents on setting reactions compound
the complicated nature of cement
chemistry.

     The influence of a limited num-
ber of organic compounds on the mic-
rostructure and engineering proper-
ties of hydrated cement has been
investigated (Ramachandran, 1971).
These compounds include sugars, lig-
nosulfates, carboxylic acids, tri-
ethanolamine, and others.  One inor-
ganic substance, calcium chloride, an
inexpensive and effective accelera-
tor, has been extensively studied
(Ramachandran, 1971).  Calcium chlo-
ride accelerates hydration of trical-
cium silicate.  Morphological altera-
tion of the hydrated calcium silicate
gel and calcium hydroxide, along with
changes in CaO/SiO  and HO/ SiO
ratios, surface area, and pore-size
distributions have been documented
(Ramachandran, 1971; Odler, 1971; and
Collepardi, 1972).

Interfering Mechanisms

     In this section attention is
given to conceptual models of inter-
fering mechanisms.  These models
include interference via adsorption,
complexation, precipitation, and
nucleation,

Adsorption

     One possible interfering mecha-
nism is adsorption of additive mole-
cules by crystalline particles
thereby blocking the normal hydration
reactions.  Studies (Young, 1970)
have shown that the retarding effect
of organic compounds are related to
their adsorption on metastable hexa-
gonal calcium aluminate hydrates.
The organic compound inhibits crystal
growth and conversion to calcium
aluminate hydrates.  The inhibiting
effect roughly correlates with the
number of hydroxyl, carboxylic, and
carbonyl groups in the organic mole-
cule.  Hansen (1952 and 1959) noted
the effect of two particular families
of organic compounds, lignosulfonic
acid derivatives and hydroxylated
carboxylic acids, on setting reac-
tions.  Lignosulfonates are strongly
adsorbed onto tricalcium aluminate
(Blank, et al., 1963).  The adsorp-
tion of calcium lignosulfonate onto
tricalcium aluminate results in a
relatively thick film or layer.  The
strong adsorption and thick layering
of lignosulfonates onto tricalcium
aluminate is indicative of a chemical
reaction involving the organic and
tricalcium aluminate hydration pro-
duct.  Taplin (1962) found retarding
effects from aliphatic and aromatic
dicarboxylic acids (e.g. maleic
acid).  In alkaline solutions where
maleic acid has no hydroxyl group for
a hydrogen adsorption bond, chela,tion
may be the interference mechanism.

     Although adsorption of organic
retarders is primarily on tricalcium
aluminate, retardation is due to ad-
sorption on tricalcium silicate.
There is no evidence of adsorption
onto anhydrous surfaces.  Organic
additives can have an important bear-
ing on reaction rates during cement
hydration.

Complexation

     Taplin (1962) related the re-
tarding activity of organic compounds
to the proximity of oxygen atoms to
carbon atoms.  He observed that the
compounds with oxy-functional groups,
in close proximity to each other,
were also indicative of retarder ef-
fectiveness, and that chelation to
metal ions could be an important fac-
tor in set retardation.  Calcium ions
can chelate with various hydroxyl or
carboxylic acids, but the retarder or
accelerators (respectively) are so
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dilute that the complexation of the
calcium is not an important factor
(Young, 1972).

     The effects of complexing cal-
cium are more significant when the
additive to affected-ion ratio is
very large and when the affected ion
is important to the setting system.
Such would be the case for the alu—
minate and ferrite ions.  Researchers
(Kalousek, 1943, and Roberts, 1967)
have shown that the addition of su-
crose increases the concentration of
alumina and calcium ions to above
normal levels.  Experiments (Young,
1972) with tricalcium aluminate indi-
cate that 1 percent by weight addi-
tions of sucrose, succinic acid and
tartaric acid increase the amounts of
calcium and alumina in solution at
first, but concentrations later de-
crease to normal or below normal.
Silica concentrations are also in-
creased when additives that affect
alumina concentrations are used.
Apparently, conditions in a cement
paste are favorable to aluminate,
ferrite and silicate ion complexa-
tion.  It is possible that complexa-
tion delays the formation of hydra-
tion products.  When cement forming
ions are kept in solution by complex-
ation, hydration barriers are estab-
lished that retard the set.  Waste
components that chelate or complex
toxic constituents may also acceler-
ate their leaching even if the waste
is successfully solidified.

Precipitation

     The formation of insoluble pre-
cipitates by additives reacting with
cement compounds is conceptually not
a realistic mechanism of admixture
interference.  Certainly the forma-
tion of insoluble compounds could
impede water transport, solubility,
and subsequent hydration reactions.
However, if retardation is due to
precipitation, then the process
should be non-selective.  In this
case, tricalcium silicate and
alurainate would both release calcium
ions and the resulting effect on set-
ting should be equally weighed among
both compounds.

Nucleation

     The inhibition of nucleation of
crystalline calcium hydroxide by sol-
uble silica is believed to be the
self-retarding set feature of trical-
cium silicate hydration.  Growth of a
crystalline matrix is retarded by the
adsorbed silica ions when a hydrated
calcium silicate gel layer results in
a diffusion barrier to calcium hy-
droxide.  Eventually crystal growth
results in the adsorbed silica being
trapped in the crystalline matrix as
the hydration process continues.
Prismatic growth of calcium hydroxide
results from differential adsorption
of silica on calcium hydroxide crys-
tal faces (Young, 1972).

     It is postulated that organic
retarders act much the same as silica
ions being adsorbed onto the calcium
hydroxide nuclei.  However because of
more retarders being'solubilized, the
organic retarders are much more ef-
fective in being adsorbed and more
completely cover crystal growth sur-
faces.  The resulting retardation of
crystal growth causes the formation
of more crystallite nuclei in the
saturated solution.  The net effect
of crystal growth on this many nuclei
is acceleration of tricalcium sili-
cate hydration following the initial
retardation period (Young, 1972).  A
one percent (by weight) of a strong
retarding agent, completely inhibits
tricalcium silicate hydration.  Addi-
tion of prehydrated tricalcium sili-
cate has been found to overcome the
effect of the organic retarder indi-
cating the merit of an adsorption/
nucleation model.
                                     324

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Effects of Organic Compounds cm Phys-
ical Properties

Accelerators

     Any compound that promotes the
nucleation and growth of calcium
hydroxide will be an effective accel-
erator.  The most commonly used or-
ganic accelerator of hydraulic cement
is triethanolamine (TEA).  At addi-
tion rates less than 0.06 percent by
weight of cement, TEA is an accelera-
tor.  At greater dosages, TEA is a
retarder.  Calcium formate is another
common accelerator.  The addition of
calcium chloride to the cement mix-
ture accelerates crystal growth by
eliminating the necessity for ions to
move from the Tricalcium silicate
structure into solution.  Both TEA
and calcium formate have been shown
to improve the 28 day compressive
strength of Portland cement concrete.
Formaldehyde and paraformaldehyde de-
crease the 28 day compressive
strength at higher dosage rates
(Rosskopf, et al., 1975).

Retarders

     Early strengths are lower in
concrete specimens with retarders
than those without.  However, as the
age of the specimens increase, those
containing retarders generally have
higher compressive strength and com-
parable flexural strength.  The
drying-shrinkages of specimens con-
taining retarders are also comparable
to those without retarders.  It is
interesting to note that soluble cal-
cium salts which provide anions that
adsorb onto the calcium hydroxide
crystal surfaces cause a retarding
effect (e.g. calcium nitrate).

Waste Binding Systems and Interfer-
ences Selected for Study

     Portland cement, lime-pozzolan,
and gypsum cement have been used in
conjunction with other additives
(e.g. flyash) to stabilize/solidify
industrial waste sludge.  Lime-poz-
zolan mixtures are frequently used to
convert liquids and semi-solids to a
solid form.  Systems selected for
testing are those found in use in
waste treatment and judged to have
potential widespread application.
Type I Portland cement and Type I
Portland cement with flyash were
chosen for immediate investigation.
A lime-pozzolanie cement and a gypsum
cement formulation will be used in
subsequent experimentation.

     Ten (10) materials with proper-
ties known or suspected to interfere
with the S/S process were chosen for
study.  The frequency and concentra-
tion with which these materials are
commonly found in waste streams con-
sidered for S/S processing were also
considered.  The interfering materi-
als selected for study are:  (1) oil
and grease| (2) light weight oil;
(3) phenol; (4) sulfates; (5) strong
base; (6) pesticide; (7) degreaserj
(8) lead; (9) copper; and (10) zinc.

Synthetic Waste Sludge Deyelopment

     The synthetic sludge to be used
in this study was generated by treat-
ing a synthetic wastewater containing
cadmium, chromium, mercury, and
nickel with hydrated lime to yield a
hydroxide sludge containing these
metals in concentrations at least
100 times that necessary to cause
rejection on the basis of the EP Tox-
icity Test (eg. 100 ppm Cd, 500 ppm
Cr and Ni, 20 ppm Hg).  Synthetic
wastewater was prepared in 500-gallon
batches using the nitrate salts of
the above metals.  After allowing
sufficient mixing time for equilibra-
tion, hydrated lime was added in a
sufficient quantity to produce a pH
of at least 10.  Following a period
of rapid mixing and slow mixing to
allow for floe formation, the mixture
was maintained under quiescent condi-
tions for a minimum period of 24 hrs
to provide for settling and sludge
accumulation.  Clear water above the
                                     325

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   TABLE 1.   REQUIRED SAMPLES  FOR STABILIZATION/SOLIDIFICATION PROJECT-FY85


   FroctiiMt Foctl*ed ecmvnt and pott land ceE«nt/f lyaih
   In£*rf«ift|t Afuscit Oil mud Crease, oil, ph«nol, sulfate, caustic* pesticida, degreaser, lend) copper, and zinc

test
» Unfit
Contt Indtx
(tell)
daralty
Wst/Bry
(IS cycles)
(dual sxcept
(or control)
X-ray mat SOt
(sins.!* except
for control.

Test Period
24 ? 28
hr day day
XXX
XXX
3t
X
X

test Period
24 7 28
Speciswns hr dsy day Specimens
1 X 2
6 XXX 6
(2 x 3)
9 XXX 9
(3 x 3)
2 X 2
1 X 2
0 or 1 X 1

24 7 28
hr dsy day Specimens
X J
XXX 6
XXX 9
X 2
X 2
X I

24 7 28
hr day day Specimens
X 2
XXX 6
XXX 9
X 2
X 2

Total Required
Specimens Sarcples
8 0*
24 24
36 36
8 0*
7 7
(4 in. dian)
3 or 4 0*
   third control)
                                                                       (2.8 in, dlas)
    Tile vtfghe/dansit? measurement will be obtained using the 28-day Cone Index (CX) saaples. After the CI is obtained, the samples Hill be
    broktn iaco pieces and subsavples will be taken £or the EP and X-r&y/SEM tests.
sludge was  decanted and the  sludge
transferred to a holding tank In
preparation for dewatering.   Dewater-
Ing to approximately 25% solids  was
achieved  using a drum vacuum filter.
Approximately 150 pounds of  sludge is
produced  in each batch.  Fresh sludge
will be prepared on a regular basis
so that all sludge used in the inter-
ference portion of the study will
have a maximum age of seven  days.

Work to be  Conducted in FY 85

     The  initial laboratory  work to
be conducted in FY 85 will involve
development of the required  amounts
for the S/S additives used in the
Portland  cement and portland cement/
flyash processes.  These amounts will
be established by preparing  serial
batches of  solidified sludge, allow-
ing representative samples to cure
for 28 days, and determining the un-
confined  compressive strength (UCS)
of each sample.  A baseline  dosage
rate will be determined.  The base-
line dosage is the minimum dosage
required  to  produce a UCS of  100  psi
using a minimum amount of additives.
Work will also be conducted on  the
installation and calibration  of
equipment to be used later in the
study, documentation of sample  prep-
aration and  testing procedures, and
the development and verification
techniques for preparing and  adding
interfering  agents to the synthetic
waste sludge.

     Work on preparation of solidi-
fied specimens of sludge containing
the interfering agents is scheduled
to begin  in  January 1985.  Work will
be conducted on one S/S process at a
time.  A  list of the samples  to be
prepared  and corresponding testing to
be conducted is presented in  Table 1.
As indicated, aliquots of four
sludge/interfering agent mixtures (0,
2, 5, and 8  percent interfering agent
by weight) will be solidified and
test samples prepared.  All four
aliquots  will be obtained from  the
same batch of sludge.  Testing  will
include EP,  cone index, UCS,
                                       326

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weight/density, wet/dry durability,
X-ray and scanning electron micro-
scopy, and permeability.  Cone index
and UCS testing will be conducted on
samples aged for 24 hrs, 7, and
28 days.  Other testing will be con-
ducted on 28-day samples.  Sample
preparation for each S/S process will
require approximately 20 weeks.  Data
evaluation will be conducted on a.
continuing basis as test results
become available.

ACKNOWLEDGEMENTS

     This study is part of a major
research program that is now being
conducted by the U. S. Army Engineer
Waterways Experiment Station and
funded by the Environmental Protec-
tion Agency, Municipal Environmental
Research Laboratory, Solid and Haz-
ardous Waste Research Division, Cin-
cinnati, Ohio, under Interagency
Agreement DW96930146-01.  Carlton C.
Wiles is the EPA Project Officer for
this research area.

REFERENCES

Blank, B., D. R. Rossington, and
     L. A. Weinland, 1963.  "Absorp-
     tion of Admixtures on Portland
     Cement, American CeramicsSoci-
     ety, Vol. 46, p. 395.

Collepardi, M., and B. Morchese,
     1972.  "Morphology and Surface
     Properties of rtydrated Trical-
     cium Silicate Pastes," Cement
     and Concrete Research, Vol. 2,
     p. 57.

Hansen, W. C., 1952.  Proc. Third
     Intern. Symp. Chemistry of
     Cements, Cement and Concrete
     Assoc., London, pp 598,

Hansen, W. C.  1959, Symposium of
     effect of Water-Reducing Admix-
     tures and Set-Retarding Admix-
     tures on Properties on Concrete,
     Amer. Soc. Test, Mat. Spec. Pub.
     266, p. 3.
Kalousek, G. L., Jumper, C. H. and
     Tregoning, J. J., 1943.  "Com-
     position and Physical Properties
     of Aqueous Extracts from Port-
     land Cement Clinker Pastes Con-
     taining Added Materials," Jour.
     Res. Natl. Bur. Stand., V. 30,
     p. 215.

Odler, L., and Skalny, J., 1971.
     Jour, of Amer. Ceram. Soc.,
     V. 54, p. 362.

Ramachandran, V. S., Mater. Struct.
     (R1LEM), 4, 3 (1971).

Roberts, M. H., 1967.  "Effect of
     Admixtures on the Composition of
     the Liquid Phase and the Early
     Hydration Reactions in Portland
     Cement Pastes, RILEM Symposium
     on Admixtures for Mortar and
     Concrete, Brussels.
     Station (England) _
     61/68.
 Bldg.  Res.
	 Paper
Rosskopf, P. A., Linton, F. J., and
     Peppier, R. B., 1975.  "Effect
     of Various Accelerating Chemical
     Admixtures on Setting and
     Strength Development of Con-
     crete," Journal of Testing and
     Evaluation, Vol. 3, No. 4^
     pp. 322-330.

Suzuki, S., and Nlshi, S., 1959.
     Semento Gijutsu Nenpo., V. 13,
     p. 160.

Taplin, J. H., 1962.  Discussion of
     paper by H. E. Vivian, Fourth
     Intern. Symp. Chemistry of Ce-
     ments , Wash. D, C., U. S.
     National Bureau of Stds. Monogr.
     43, Vol II, p. 924.

Young, J. F., 1970.  J. Amer. Ceram.
     Soc. V. 53, p. 65.

Young, J. F., 1972.  A Review of the
     Mechanisms of Set-Retardation in
     Portland Cement Pastes Contain-
     ing Organic Admixtures, Cement
     Concr. Res., Vol. 2, pp. 415-433.
                                     327

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        A PROCEDURE FOR CHARACTERIZING INTERACTIONS OF ORGANICS
  WITH CEMENT:  EFFECTS OF ORGANICS ON SOLIDIFICATION/STABILIZATION

                  M, E. Tittlebaum, F. K. Cartledge,
                  D. Chalasani, H. Eaton and M. Walsh
                 The Hazardous Waste Research Center,
            The Colleges of Engineering and Basic Sciences
                      Louisiana State University
                        Baton Rouge, LA 70803
                               ABSTRACT

     The effects  of  organics on the setting  reactions  of hydrating Port-
land cement  and  on  the eventual  structure  of the  hydrated cement paste
have been  studied by  a combination of  techniques  including  solvent  ex-
tractions with  solvents of  varying polarities,  scanning electron micro-
scopy,   energy  dispersive  X-ray  analysis  and  X-ray powder diffraction.
When ethylene  glycol  (EG)  is solidified with  cement,  the  EG appears to
occupy  at  least  3  different kinds  of  sites, characterized  by differing
extractability.   Gross  alterations of  the morphology of the cement matrix
do not  become  apparent until rather large amounts  of  EG (EG/cement =0.1
by weight) have been added to the  hydrating cement mixture.  At that point
the structure  is  clearly weakened, and the  EG  is more  readily extracted.
However,  at  concentratons   below  the  point  at  which  major structural
changes  take  place,  there  is evidence from  X-ray  diffraction that EG is
entering the  semi-crystalline calcium silicate hydrate (C-S-H) gel phase
and altering its  structure.   Since the C-S-H gel phase comprises more than
half of the hardened cement paste, alterations to that phase can be expec-
ted to alter the  ability of the cement to immobilize wastes in solidifica-
tion/stabilization processes.
INTRODUCTION
                   work  was  under-
                  a larger study of
     The  present
taken as  part  of
techniques    of    solidification/
stabilization  used  for immobiliza-
tion  of wastes  prior  to  landfil-
ling,  roadbed  construction,  etc.
The  technology has  been  most com-
monly studied  as  a  potential tech-
nique  for immobilization  of toxic
metal  ions  or  radioactive  waste.
Complete  detoxification of  metals
by  chemical,   biological  or  other
means  is  impossible short  of ele-
mental     transmutation;     hence,
methods which dilute and/or isolate
the metals are necessary as part of
waste  management   schemes.    Many
vendors  of solidification/stabili-
zation  technology  have  presented
leaching data  claiming  to  show the
efficacy of  various immobilization
techniques;  although  claims  con-
                                   328

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earning  the   nature   of  chemical
interactions  between  waste  metal
ions  and  the  fixing  agents  have
remained unsubstantiated(l).

     The two principal  constituents
of  most commercial  fixing agents
are  cementitious materials  (Port-
land  cement,   fly  ash,  etc.)  and
soluble  silicates.    A  limitation
often  cited  is that the processes
are incompatible with organics, but
details of such incompatibility are
generally   not  available(2).    A
potential concern is that organics,
even  in. small  amounts,  can  alter
the  process  sufficiently   to  sub-
stantially decrease the  ability of
the  fixing  agents  to  immobilize
metal  ions.    Indeed,  it   is  well
known  that  organics  can alter the
setting characteristics of Portland
cement.  It  is not clear  whether,
and at what concentration,  organics
interfere   with   the   relatively
complex setting reactions resulting
in  a  significantly altered cement
matrix.   The   question  is  of  in-
terest,  not just  with  respect  to
solidification/stabilization  tech-
nology,  but  also  with  regard  to
fundamental understanding of cemen-
ting reactions.

     Polyhydroxy   compounds    are
among the classes of organics which
alter  the  setting  characteristics
of Portland cement.   The effects of
relatively small  amounts (up to 0.5
percent)  of triethanolamine  (TEA)
on  the setting  characteristics  of
Portland cement  have  been  studied,
mainly  using   differential  thermal
analysis,  thermogravimetric analy-
sis  and  conduction calorimetry(S).
At  amounts  from  0.17  to  0.5  per-
cent,  TEA  greatly accelerates the
initial set, but  retards the final
set  and produces  a weaker cement
structure.   The  results have  sug-
gested  "a  complex  formed  between
TEA and the hydrating components of
Portland cement."

     The   present   study  involves
ethylene  glycol  (EG)  and presents
data relating to  the presence of a
chemical   interaction  between  or-
ganics  and Portland cement.   Ethy-
lene glycol was  chosen for initial
study  for  several   reasons.   It is
completely miscible with water, and
hence cement pastes can be prepared
with  any  concentration  of  EG  in
water and  in  all  cases a homogene-
ous  liquid  phase   is  being  mixed
with  the  unhydrated  cement.   Fur-
thermore,  there  is  evidence  in the
literature  that  EG does  have  pro-
found effects on already set cement
and the mineral  constituents there-
of (4, 5).   When  hydrated  cement or
tricalcium silicate (C~S) is treat-
ed with  EG,  etching occurs,  but it
is  unclear whether  mainly calcium
silicate  hydrate "gel"  (C-S-H) or
calcium  hydroxide   (CH)   is  dis-
solved^).

APPROACH

     The  presence  of  a  chemical
interaction  between  water-soluble
organics  and Portland cement  has
been  investigated  by  solidifying
pure ethylene glycol (EG) with type
I  Portland cement  and  water.   The
cement  used  had  the  composition
shown  in  Table  I.   Samples  were
prepared by weighing EG into a 20mL
borosilicate   glass,   screw   cap
scintillation    vial,     Portland
cement and water were added and the
mixture  stirred  to  apparent homo-
geneity  with  a  glass  stirring rod
(ca.  1 minute of  stirring).   Sam-
ples  were  allowed  to  cure  for
variable lengths of time.   Most of
the  samples in  the  present  study
were prepared using 4.0ml_ of water
and  10.Og  of  cement and sufficient
EG to  give EG/cement weight ratios
                                   329

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Table 1  Percent   Composition   of
         Portland  Cement  Used  in
         the Present Study
               Si0
               A1203
               CaO

               MgO

               K20

               SO.
20.6%

 5.2%

 2.4%

64.9%

 3.3%

 0.6%

 2.9%
of  0.02,  0.04,  0.1, 0.2,  0.5  and
1.0.

     Extractions  of ground  cement
pastes were carried  out with three
solvents:    dichloromethane   (DCM)
(dielectric   constant = 8.9,   po-
larity  index(6)  = 3.1);   dimethyl
sulfoxide (DMSO)(D =47, PI = 7.2);
and   water  (D = 80;   PI = 10.2).
After the  appropriate  curing time,
the  vials  were   broken   and  the
samples were  ground with  a  mortar
and  pestle  to  pass  a  100  mesh
screen.   The powder  and the pieces
of broken glass  from the vial were
transferred to a  125mL Erlenmeyer
flask, mixed with 120mL of solvent
and  shaken  for   0.5   hour.    The
mixtures were  filtered  under suc-
tion  using  Whatman  No. 41  filter
paper and  analyzed  by  gas chroma-
tography  using  a Hewlett Packard
HP5790A  gas chromatograph coupled
to a HP3390A integrator and a flame
ionization detector.  A 6 foot by %
inch OD (2mm  ID)  80/100 mesh TENAX
glass column  was  used.   Quantita-
tion  was  performed  using  internal
standards.     For  water   and  DCM
extractions,   1,3-propanediol   was
the  internal   standard;  for  DMSO
extractions   2-propanol   was   the
internal  standard.    In  some  pre-
liminary work  on solidification of
decanol, gas chromatographic analy-
sis  was done  using  a 25 meter by
0.31mm  ID  5%  phenylmethylsilicone
column  and  1-octanol  as  the inter-
nal standard.

     Examination   of   unextracted
samples  was  also  carried  out  by
scanning electron  microscopy (SEM)
and X-ray powder diffraction (XRD).
Each  sample was  cooled  to  liquid
nitrogen   temperature   and   then
fractured  into  several  small  pie-
ces,   each   approximately   1mm  in
diameter.   A  representative  piece
was  mounted onto an  aluminum  stub
for scanning electron microscopy in
an   ISI  60-A   Scanning  Electron
Microscope  (SEM).    Prior  to  ex-
amination,  the  mounted  sample was
coated  with a 20 nm  film  of Au-Pd
in  a   Hummer  VI  Sputter  Coater.

     The SEM was operated  at 15-30
keV  accelerating voltage with the
vacuum  chamber _at  a  pressure  of
less than 5 x 10   torr.   When fine
surface  textures were observed at
high   magnifications,   the   lower
voltages were necessary in order to
reduce  beam  penetration.    Micro-
chemical analyses were made with an
EDAX-ECON 2 Energy Dispersive X-Ray
Analyzer and  x-ray  powder diffrac-
tion  analysis  by  a GE  X-Ray  Dif-
fractometer  with a magnesium  tar-
get.

PROBLEMS ENCOUNTERED

Sample  Preparation and
Reproducibility

     At the outset of the  project
we  anticipated using  organics  of a
number  of  different types  and in a
wide  range  of concentrations.   The
result  of this is that the "solidi-
                                   330

-------
tied"   samples   vary   greatly  in
character  from  solid   masses  much
like  set  cement,  to non-solidified
"soups",  to  solid mass  with  free-
standing liquid.
     None  of the  standard  methods
of specimen preparation is strictly
applicable to the  conditions asso-
ciated  with  the present  research.
Due to  the heterogeneous  nature of
some   of  the   samples,   reliable
partitioning  of  large  solidified
samples  would   not   be  possible.
Hence   each  sample   needs   to  be
prepared  separately  and  must  be
capable  of being transferred quan-
titatively   at   each   stage  from
mixing  to  curing to  analysis.   An
additional concern in  our work has
been to limit the volatilization of
the   organic   admixture.    These
experimental  restrictions  have led
us  to   choose  to prepare  and  cure
samples  in  the  same  container and
to  use sealable  glass vials.   In
the sealed  vial  the  partial  pres-
sures  of water  or organic  vapors
above  the solid probably  rapidly
reach  equilibrium  values, although
it  is  possible  that  as  setting
reactions continue,  those equilib-
rium partial  pressures may  change
slightly.    Special    temperature
control  is  not  being  applied,  and
room temperature is  in  the  range
23°±2°C,  Samples  are  being  stored
in  the  dark to  avoid any  possi-
bility  of photochemical  reactions
of the organics.

     We were concerned with  repro-
ducibility   from   the   beginning
because  of  the  large  number  of
samples  being  prepared.  The  best
indicator we  have  that assures  us
of  reliable  sample  replication  is
the   extraction   behavior.    With
occasional exceptions we can  repro-
duce the amount of organic recover-
ed from solidified samples prepared
by our standard procedure and cured
for the same length of time so that
the   standard   deviation   is  <10
percent  of  the   average   of  the
values in  three  to six replicates.
Usually  it is  <5  percent.   These
results give us confidence that the
trends  we  are  seeing  are  real.

RESULTS

     Some  differences  in  the sam-
ples   prepared    with   differing
EG/cement ratios are obvious to the
casual  observer.    At  the  weight
ratios  from 0.02  to 0.2  the mix-
tures  harden,  but  the  0.5 and 1.0
ratio mixtures do not.   Even at the
0.2  ratio,  the  surfaces  of  the
solidified  material appear  moist.

     The extractions  with  solvents
of differing polarities give infor-
mation  regarding  the  extent  and
                   binding
                    cement
reversibility  of
ganics   to   the
Changing solvent polarity
expected to  have
                            of  or-
                            matrix.
                           would, be
                     number of pos-
sible  effects  on  the  extraction
behavior.   Intermolecular interac-
tions between  EG  and the solvents,
particularly    dipole-dipole    and
hydrogen  bonding  will  increase in
strength  in  the order DCM < DMSO <
FLO.  The solvent interactions with
tne  cement  matrix will  also  vary.
The  ability  of  HpO  to  dissolve
Ca(OH)?, and perhaps other constit-
uents as well,  out of  the  cement
paste may mean  that water penetra-
tion  into  the  material  will  be
greater  than  that  of  the  other
solvents, thus having the effect of
freeing  more  of any  organic  which
was  simply  physically  trapped in
areas of the matrix inaccessible to
the  solvent.  We  are not convinced
that the latter argument  is  valid
under   our   conditions.    When  1-
decanol,  a  quite  nonpolar organic,
is   solidified  with   cement  and
                                  331

-------
extracted with DCM,  >85  percent of
the  decanol   is   recovered.    The
matrix  may  be  different  in  the
presence  of  decanol  than  in  the
presence  of EG,  but our  grinding
and  extracting  procedure  clearly
does free most  of  the  physically
entrapped organic.

     Some results of extractions of
1  month old  samples are  shown in
Table 2 and are  expressed as per-
cent recoveries of  EG.   Our expec-
tation   that  increasing   solvent
polarity would result in increasing
recovery of  EG was  borne out.  The
results are  clearly  not  due simply
to solubility effects, since  EG is
very soluble in all three solvents.

Table 2  Percent  Recovery  of  EG in
         Extractions  with  Various
         Solvents at Differing EG/
         Cement Weight Ratios

                       %   Recovery
                      dil*    dil**
Wt. Ratio
0.02
0.04
0.10
0.20
0.50
1.0
DCM
3.7
3.4
6.5
7.0
5.1
4.8
DMSO
12
11
15
43
54
-
base
79
79
89
83
79
84
acid
95
87
76
79
79
81
* The water  solution was initially
0.05M   in   Na7CO,,   and   0.05M  in
NaHCOg, with  Sf\  fnitial  pH of 9.9.
The  pH  after extraction was  13.

**The water  solution was initially
0.05M  in acetic  acid and  0.1M in
sodium  acetate,  with an  intial  pH
of  5.0.   The  pH  after  extraction
was 12.
Since  DCM and  DMSO extract  rela-
tively  small  amounts  of EG  (com-
pared  to  water),  and  since  our
procedure  appears   to  free  most
physically  entrapped  organic,  the
reasonable  conclusion   to  draw  is
that there is  some  chemical  inter-
action  between  EG  and  the  cement
matrix  that  is  stronger than  the
EG-DCM  or  EG-DMSO  intermolecular
interactions.   The interaction that
is  certainly present   is  hydrogen
bonding, and that interaction alone
is  probably  sufficient  to  explain
the  relative extracting abilities
of the 3 solvents.

     The  loading  of  EG on  cement
might   be  expected  to  influence
extractability  very substantially,
since  bound  EG  could  be  in quite
different  environments,   and  the
cement  matrix  might be  quite dif-
ferent  at different EG concentra-
tions.   Surprisingly, any effect is
obvious  only  in  the case of DMSO
extraction.  In that case  there is
a  major break in  behavior  between
weight  ratios  of 0.1  and  0.2.   We
have concentrated on  that  concen-
tration  range  in  the  microstruc-
tural  characterization  to   be  de-
scribed below.

     The extent to  which any EG is
irreversibly  bound  in  the  cement
matrix  has  been  investigated  by
repeated  extractions  of the same
sample  with  water and  DMSO  (Table
3).  In these experiments the solid
residue  after the  initial  extrac-
tion  was  treated  with  a  second
120mL  of  solvent, reshaken,  refil-
tered  and  analyzed.    The  samples
were only  ground  one time.   All of
the EG  has not been recovered after
5  extractions with  the most agres-
sive  solvent, water.    Evaporative
losses  are  possible,   but  we  are
using  very  non-volatile organics;
and   deliberately   allowing   the
                                    332

-------
Table 3  Percent  Recovery  in  Re-
         peated Extractions of
         0.04   EG/cement   Samples
% Recovery*
Extraction No.
1
2
3
4
5
TOTAL
H 0**
£.
88
5.2
0.53
0.16
0.13
94.2
DMSO
12
1.8
0.4
-
-
14.2
*  Expressed  as   percent  of  the
original  amount   of  EG   in  the
sample.

** Deionized water.
solids to stand open to the air for
an hour or more prior to extraction
did  not  appear  to affect  the  re-
sults.   A  similar phenomenon  was
observed   in   extractions   of  0.1
weight ratio  1-decanol/cement with
DCM.   After  3 extractions  97 per-
cent  of  the  decanol  was recovered,
and  decanol  could not  be  detected
in   the   fourth   extraction.    We
conclude  from the  decanol  results
that  there are  sites  in the matrix
where physically trapped organic is
isolated   from   contact  with  the
extracting  solvent.   Water  is  a
much  more  aggressive  solvent than
DCM and can be expected to etch the
cement matrix, and yet even after 5
extractions  there  are  significant
amounts  of EG unaccounted  for.   We
conclude that there are sites where
EG  is bound  more tightly  than by
surface  hydrogen   bonding  and/or
that  there are  sites  in the cement
matrix that  are  very poorly acces-
sible to water.

     The  age  of  the  sample  does
affect  extraction  behavior  (Table
4).   Again   the  DMSO  extraction
seems most sensitive to  changes in
the  environment  of  the  EG.   The
hydration  reactions  will  be  only
partially  complete  at 7  days  of
cure.  The DMSO extraction results,
in  comparison to  the hLO  extrac-
tions,  suggest that theTe  are  at
least  two qualitatively  different
                                       Table 4  Percent Recovery  of EG in
                                                Extractions  with  Various
                                                Solvents at  Various Times
                                                of Cure
                    % Recovery

Wt. Ratio*  7-day Cure  28-day Cure
   0.04

   0.1



   0.04

   0.1
  HpQ Extraction

79           79

74           78

  DMSO Extraction

II            7.4

27           16

  DCM Extraction
0.04
0.1
4.8
6.8
3.6
7.1
*  The samples  in this  table were
prepared in a different manner from
those cited elsewhere in the paper.
In all these samples, regardless of
the  EG/cement  ratio, the  ratio of
volume  of   liquid  to   weight  of
cement  was   kept  constant  at 0.4.
                                  333

-------
environments   in   which  EG  finds
itself,  a more  tightly  bound  one
and  a  less tightly  bound one;  and
the  proportion of  EG  in  the more
tightly bound environment is higher
at  lower EG concentrations  and at
longer times of cure.

SEH Observations

     A   calcium   silicate  hydrate
(C-S-H)   gel   phase   constitutes
approximately   one-half   to   two-
thirds  of the  volume  of hydrated
pastes,  and  consequently, strongly
influences their behavior.

     Calcium   hydroxide   crystals
constitute  20-25  percent  of  the
paste  volume.   As the  paste ages,
the  calcium  hydroxide  becomes  an
increasingly  prominent  constituent
of the microstructure.  Researchers
utilizing  the electron microscope
to  characterize  Ca(OH),,  commonly
observe   hexagonal   places.    The
scanning    electron    micrographs
reveal   the  presence  of this phase
in both  plain  and waste containing
cements.

     Of    considerable    practical
interest  is  the   concentration  of
organic  required  to  make signifi-
cant changes  in the  cement matrix.
It is  reasonable  to  assume that if
the matrix is considerably altered,
the  ability  of  the  matrix  to  im-
mobilize  both metal  ions  and  or-
ganics  will  be  altered.    SEM  ob-
servations of  the gross morphology
of fracture surfaces  of the solidi-
fied  samples  reveal  few  obvious
differences  between  specimens  of
hydrated  cement alone and hydrated
cement  containing "low" concentra-
tions  of  EG.   At  the  0.1 weight
ratio,  however, significant differ-
ences are obvious.   Figure 1 shows
micrographs taken at  relatively low
magnification  under  conditions  as
nearly  identical  as  possible.   In
the  figure,  a  contains no  EG,  b:
0.04  EG/cement,  c:   0.1 EG/cement,
d:    0.2  EG/cement.    At  higher
magnifications  it  is  possible  to
find  features  that  have  similar
appearances,  particularly  in  a,  b
and c.  However, the differences in
appearance  are  strikingly evident
in  the  general  views  at 300X.   In
particular, massive  structures and
regions   of   crystal!inity  become
much  less common as  EG concentra-
tion  increases,  until  finally  d
bears little resemblance to a.   The
differences between  a  and  b might
well  go  unnoticed  if  the  other
members   of  the  series  were  not
available for comparison.

X-RayPowder Diffraction Observa-
tions
     Each  sample  was  analyzed
x-ray  powder diffraction  prior
each    microstructural
This  has  been  found
useful   since   changes
crystalline   components
waste/binder  sample   can
               by
               to
        analysis.
      to  be  very
          in   the
          of   the
        be deter-
mined  if  the  quantities  of  the
phases  are  sufficient.   Figure  2
shows XRD  data  in a graphical form
for  the  same 4  samples shown  in
Figure  1,  also identified  here  as
a-d.  The  trend  away from crystal-
1inity   as  EG   concentration  in-
creases is evident in these graphs,
as  it  is  in  the  micrographs.   The
trace  for sample  d is  quite  fea-
tureless  compared to that  for the
other samples.  It  is  worth noting
that in the two samples at lower EG
concentration,  the   same  general
features  are  apparent  as  in  the
cement    control     sample.     The
crystalline  component of  hydrated
cement that  is  easiest to identify
is  Ca(OH)?.   One
Ca(OH)2 peaks  is
plots along with
 of  the prominent
identified on the
peaks ascribed to
                                    334

-------
C-S-H  gel.    Even  sample  b  shows
distinct changes in the fine struc-
ture of  the peaks associated  with
C-S-H  gel.   It  thus appears  that
while  the  crystalline,  or  semi-
crystalline  phases  characteristic
of  hydrated  Portland   cement  con-
tinue to be  present  as  significant
quantities of organic are  added to
the  hydrating  mixture, there  are
significant  changes  in the  amor-
phous or semi-crystalline C-S-H gel
phase  at  relatively  low  organic
concentrations.

CONCLUSIONS

     When  EG  is  solidified  with
cement, the EG appears  to occupy at
least  three  different  kinds  of
environments.   At high concentra-
tions of EG, there is a significant
amount  of  very  loosely bound  EG,
which  can  be extracted  readily by
either  DMSO  or HJ3.   The  second
environment  contains more  tightly
bound  EG,  probably  bound to  sur-
faces by hydrogen bonding, and such
EG can be  readily  extracted by H?0
but  not  by  DMSO.   The  EG  still
remaining  after  repeated  extrac-
tions  with  HpO  or  DMSO  can  be
considered  to  occupy  a third  en-
vironment.    Conceivably  this  en-
vironment could  be one  in which EG
replaces  water   of  crystallization
in some  of the  crystalline  struc-
tures.    However,  the   alterations
that are  obvious by XRD  are those
in the semi-crystalline  C-S-H  gel
phase,  and  we suggest  that  the EG
is  located  there.    The  Feldman-
Sereda model(7)  of  hardened cement
paste  includes   an environment  for
water between layers of C-S-H.   EG
could substitute for water in such
an environment   and  be  both  chem-
ically  bound,   probably mainly  by
hydrogen  bonding,  and  also  physi-
cally  inaccessible  to  extracting
solvents.
     The EG  being  added to solidi-
fying  cement   does   not  have  an
effect  on  the  developing  cement
matrix  which  is  obvious  to  the
naked  eye  until  the concentration
of  EG  is rather  high (EG/cement =
0.2).  At that point the changes in
structure can  be seen  in the SEM,
but  are  also obvious  to the naked
eye.    At   lower   concentrations,
however,  there   are  more  subtle
changes, which  are clearly evident
to  XRD.   The  changes  appear  to
involve  the semicrystalline  C-S-H
gel  phase, which  normally makes up
more  than  half of  the  volume  of
hydrated cement structure.  Changes
in  that  phase will  clearly influ-
ence  the physical  characteristics
of the hardened material as well as
its  ability  to  immobilize  metal
ions.

ACKNOWLEDGMENTS

     We wish to  thank River Cement
Company,  St.  Louis,  Mo.  for  pro-
viding  the  cement   used  in  the
present  study.   Financial  support
was  provided by the  USEPA through
the Hazardous Waste Research Center
of Louisiana State University.  The
USEPA   Project   Officer  for  this
study  is  Dr.   Carl ton   Wiles.   We
also wish to thank Dr.   Roger Seals
for  helpful  discussions during the
course of this research.

REFERENCES

(1)  (a) Mishuck, E., 1984, "Encap-
     sulation/Fixation Mechanisms",
     U.S. Army  Toxic and Hazardous
     Materials  Agency   Report  No.
     DRXTH-TE-CR-84298,   June  18,
     1984.
                        G.
R.   J.
(b)  Malone,  P.
Larson,    1982,    "Scientific
Basis   of   Hazardous   Waste
Immobilization", Second Annual
                                   335

-------
     ASTM  Symposium on  Testing of
     Hazardous and Industrial Solid
     Wastes,  Orlando,   FL,   June,
     1982.

     (c)  Anon.,  1979,  "Comparative
     Investigation   on  Four   Im-
     mobilization      Techniques",
     Institute  for Waste  Research
     Publication   39,   Amersfoort,
     The   Netherlands,   September,
     1979.

(2)  Tittlebaum,   M.   E.,   F.   K.
     Cartledge,   R.  W.  Seals,  S.
     Engels,    1985,    "Technical
     Feasibility  of  Stabilization
     of Hazardous  Organic Liquids"
     CRC Critical Reviews,       In
     Press.

(3)  Ramachandran,  V.   S.,   1976,
     "Hydration of Cement - Role of
     Triethanolamine"  Cem.  Concr.
     Res.,  Vol.  6,  pp.  623-631.

(4)  Schlapfer,   P.,  P.   Esenwein,
     1936, "Untersuchungen uber die
     Einwirkung  von Aethylenglycol
     and  Glycerin  auf verschiedene
     Kalzi urn      alumi nathydrate",
     Zement, Vol.  25,  pp.  814-816.

(5)  Ciach, T.  D., J. E.  Gillott,
     E.  G.  Swenson, P.  J.  Sereda,
     1971,    "Microstructure    of
     Calcium  Silicate  Hydrates",
     Cem.  Concr. Res., Vol.  1, pp.
     IF25I

(6)  Snyder,   L.    R. ,   1978,   J.
     Chromatogr. Sci., Vol.  16, p.
     223.

(7)  Feldman,  R. F.,  P.  J.  Sereda,
     1968,  "A  Model   for  Hydrated
     Portland Cement from Sorption,
     Length  Change and  Heehanieal
     Properties",     Materiaux et
     Constructions. Vol.  1,  p.  509.
              Disclaimer

This paper has been reviewed in
accordance with the U.S. Environ-
mental Protection Agency peer and
administrative review policies and
approved for presentation and publi-
cation.
                                     336

-------
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5C^>/if'^i *'.*^c^v^^'-  ^*

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       a. CONTROL
                           b. 0.04 EG/cemtnt
          . .  »4   nr •
          .-*  '>.  -• V • -

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                                     ^^,%M''4f
     ^"> •&«».•* J*y--«-- *-*r-  TIP- i^rvvw^y, ^f-A8' "••*'/*i-*'^:jr.
     ft i m^-- -^ - •>  «4 4W x-i7^• • '^; /fe
     ^ Ci  i %> l%  W$W&*i*'&&
     &Mf&.*.  &*$n'$i!m
                  (A
    c. 0.1 EG/c«mtnt            d. 0.2 EG/c«m«nt


           FIGURE I.  MICROGRAPHS OF

VARIOUS ETHYLENE GLYCOL/CEMENT SAMPLES AT 300 X
                    337

-------
                   CSH
                   CH

                 *    *
                 * *  *.*."_»
                 •*"•.""• „*"-* •
                   *>
                 • • .v..
                               X\ .  a. CONTROL
                                * « »  *
                                             •> '."/•'.••*•
                                              • '• ^•••".'V- ••.
                                                  * *   »*« **
                                                     *




 i I i 1 i i i i i i i i i i i i i i i I i i ii i i i i i 1 i i i i i i i i i I i i i i iii i i I i ii i II I V
                                 -CH
                                 '.... b. 0.04
                                "•*   c. O.i
                                 • •..  •
                                 «*•*.*.•*.
                                  -.' •-•
                                ...."  d. 0.2

                                                 '*•*-_•
0
10         15        20

       DEGREE 2 THETA
25
30
        FIGURE  2. X-RAY POWDER DIFFRACTION OF

      VARIOUS ETHYLENE GLYCOL/CEMENT SAMPLES
                            338

-------
             THE RATIONAL USE OF  CEMENT-BASED STABILIZATION
             TECHNIQUES FOR THE DISPOSAL OF HAZARDOUS WASTES

               Alistair I. Clark, Chi S. Poon, Roger Perry
                     Department of Civil Engineering
                 Imperial College of Science & Technology
                            London SW7 2BU, UK
                                 ABSTRACT

    The mechanism of zinc and mercury fixation by a cement/sodium  silicate
stabilization process has been assessed from leaching, scanning electron
microscopy. X-ray diffraction and porosimetry studies.  The results of
these tests correlate closely and suggest the operation of two separate
fixation mechanisms.  The presence of zinc has a significant effect upon
the hydration and final physical properties of the final product.  Mercury
and related metals which do not form precipitates at elevated pH levels
are held in pore solution.  The importance of microstructure in metal
fixation and also metal leaching from the cementitious matrix has  also  ,
been demonstrated.  The calcium aluminate hydrate structure, ettringite,
has been identified as to be related to the structural integrity of the
solidified product.  The understanding of the mechanisms of action can
enable a rational, cost effective approach to process design and operation
to be achieved.
INTRODUCTION AND PURPOSE

    A number of pretreatment pro-
cesses have been developed to
render industrial wastes suitable
for final disposal.  Waste stabili-
zation methods based upon ordinary
Portland cement (OPC) or other poz-
zolanic materials provide one form
of pretreatment with landfill as an
ultimate disposal route.  The mobi-
lization of wastes into water has
always been a major consideration
in containing toxic waste, and as
such, much of the emphasis or sta-
bilization processes has been
placed on preventing the waste from
coming into contact with water and
controlling the chemical conditions
of the aqueous environment in order
to minimize solubility.
    The mode of interaction of the
inorganic waste and the stabiliza-
tion system will clealy influence
the leachability of the metal (1).
Leaching studies of certain metals
stabilized in a cement matrix have
shown that the amount present in
the leachate is often considerably
lower than the calculated value
based upon the theoretical solubi-
lity product.  A variety of fixa-
tion mechanisms have been
postulated to account for this,
involving absorption by cement
hydrates, substitution and solid
solution in the hydrate structure,
and formation of insoluble com-
pounds.  However, many of these
claims are related to semi-
quantitative observations and
interpretations, leaving many of
                                   339

-------
the fundamentals to be resolved
although the  importance of the
mlcrostructure of the cement  hyra-
tion process  in relation to the
macro properties of stabilized
waste has been emphasized  (2).

    The aims  of this study were
therefore to  identify the mecha-
nisms operative in the fixation of
hzardous heavy metal wastes by
cement-based  processes and also to
improve the existing mix criteria
of these cement-based processes."

APPROACH

    The approach adopted in this
study was to  examine certain  micro
and macro properties of stabilized
wastes using  the techniques of; (i)
X-ray diffraction (XRD), scanning
electron microscopy {SEM)t mercury
intrusion porosimetry (KIP),  and
(il) leaching tests and compressive
strength tests.  This paper reports
the results of a study of an
OPC/sodium silicate formulation
although similar work is being
undertaken by the authors at  pre-
sent on the alternative OPC/PFA
process.  Both these principal
cement-based  fixation techniques
are being marketed in Europe  and
North America.

    A simulated inorganic
industrial waste containing Zn and
Hg (both group lib elements)  was
used in this  study.  These waste
compounds were selected because of
known industrial and experimental
experiences which have indicated
that their leaching potential is
very different.  The sample pre-
paration varied according to  the
analytical procedure used and can
be summarised as follows:

Leaching Test : A solution (200 ml
of 2000 ppm)  of Zn and Hg was soli-
dified by 50 g of OPC and 12 ml 40%
Na.SiO., cured at room temperature
for 28 days, crushed into small
lumps and transferred to a. con-
tainer.  Buffered acetic acid
(100 ml of 0.15 M) was added and
the mixture agitated using a rota-
tional shaker.  After 24 h, the
slurry was filtered through a
0.45 ym membrane.  A fresh portion
of acetic acid was added and the
process repeated over a period of
time.

SEM, XRD and MIP : The composition
of the four samples analysed by
these techniques were as follows:
Sample A = 10 g OPC + 10 ml H^O?
Sample B = 10 g OPC + 10 ml H_O +
1 ml 20% Na2siO,-j Sample C = 10 g
OPC + 10 ml 2% In solution + 1 ml
20% Na2SiO3? Sample D ~ 10 g OPC +
10 ml 2% Hg solution + 1 ml 20%
    Samples were prepared by
shaking either water or metal solu-
tions with cement for 3 min in a
plastic container? Na2SiO3 solution
was then added as needed and the
mixtures shaken for a further 30 s.
All samples were allowed to cure at
room temperature.  For SEM and XRD
studies 1-day samples were oven
dried at 105°C for 15 min.
Fracture specimens were prepared
and coated with gold or carbon film
prior to SEM examination using a
Jeol 35CF + EDAX system (Energy
Dispersive Analysis of x-rays)
while powdered samples were ana-
lysed by a Philips Powder X-ray
diffractometer.  The porosity stu-
dies were performed on 7-day
samples using a Carlo Erba Mercury
Intrusion Porosimeter.

    In addition, leached solidified
waste samples (2000 ppm Zn and Hg)
of every leaching period from a
leaching experiment using 0.5 M
                                   340

-------
Buffered acetic acid and a pre-
leached solidified waste sample
were oven dried at 105°C and exa-
mined by SEM.  Powdered XED pat-
terns were obtained for solidified
materials with and without dosage
of Zn and Eg  (at the 0.2% level) as
before.

Strength Testing:  Various mixes
were prepared with different water
to cement (W/C) and silicate to
cement (Si/C) ratios.  Additional
mixes were prepared by using solu-
tions containing 2% Zn and 2% Hg.
Compressive strengths were tested
at intervals of 1, 7 and 28 days
using a standard compression test
instrument conforming to BS 4550.

RESULTS

    The results from the SEM, XRD,
MIP and leaching studies of the
four samples are summarized in
Table 1 and Figure 1.  The porosity
data for the four sample types
appear to suggest three basic dis-
tribuations: one centered at 370 A,
one centered at 7500 A, and the sum
of these two.  Such an interpreta-
tion is suggestive of at least two
separate mechanisms operating in
the interaction between these
metals and the OPC/silicate system.
Increased pore volume and pore size
of the Zn-containing samples
occurred because of the extensive
growth of ettringite crystals in
the hydrated paste due to the acce-
lerated hydration of C,A as
observed in the SEM ana XRD analy-
ses.  Despite the higher porosity
the leachability of Zn is low which
indicates that permeability is not
an important factor in determining
movement of this metal through the
matrix and that chemical stabiliza-
tion rather than physical encap-
sulation is the controlling factor
in reducing metal mobility.
    It has been claimed that stabi-
lization of metal involves the for-
mation of insoluble metal silicates
but the SEM and XRD examination did
not reveal any identifiable
crystalline zinc silicate, though
amorphous gel of calcium silicate
was observed in both pure
OPC/silicate and metal-dosed
OPC/slllcate matrices.  Under these
conditions it is thought likely
that most of the Zn would be preci-
pitated on the hydroxide or would
react with the calcium hydroxide
(OH) to produce possibly calcium
zincate (3) although no evidence of
either of these zinc compounds has
been found by the SEM or 15U) tests.
The absence of C-H crystals in the
sample containing zinc indicates
that C-H plays an important role in
the fixation of Zn as confirmed by
the semi-quantitative XRD study
which demonstrated the presence of
the more crystalline phases (Table
2).  Indeed, a recent study on
cementitious solidification of
electroplating waste confirmed the
presence of amorphous metal
hydroxides in the solidified pro-
duct (4).

    By contrast, Hg did not
seriously affect the normal hydra-
tion process as evident from the
SEM, XRD and MIP studies.  The for-
mation of calcium silicate hydrates
(..O-S-H), calcium silicate and C-H
all proceed in the same manner as
in the OPC/silicate system which
indicates that there is little or
no interaction of this metal with
OPC or sodium silicate.  This ina-
bility of Hg to form an insoluble
hydroxide or silicate with the
solidifying material means that the
metal remains In pore solution or
at most is only loosely bound to
the hydrated products through sorp-
tion.  The metal is therefore phy-
sically encapsulated within the
                                   341

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TABLE 1.
S*H?1£

A. OPC *
H20

1. OPC/


c. OPC/
Solution

D. OPC/
* H9
Solution


, SUMMARY OF CORRELATION OF FOUR STUDIES
SEH
< 1 day sample )

C-S-H
C* tOH)2
*ttringite
C-3-M
ettrinqite
c*-Biiicate
c-s-s
C« CQ8J2
ettringite
Ca~silicate
C-S-H
Ca IOH>2
ettritigite
Ca~*ilic*te

flbroua
large crystals
small rods
fibroua, hydro ted
•hell C Bad ley grain}
snail crystals
snail rods
gel massive
a little,
reticulated
absence
large hexagonal
prism with AFm
gel massive
fibrous t hydra ted
shell CHadley grain)
small crystals
snail rods
gel massive
Powder XRO PG cosine try Total Pore
C1 day sample) <7 days sample) Volume
Con3.?"*1 )
Unhydrated cement medium strong single 0. 136
Ca (OHJ2 strong
ettringite weak 3?QA
Unhyd rated cement medium strong double 0.416
Ca (OK)2 cMsdiun! 370ft,
ettringlte weak 7SOOA


y 99
Ca EQK ) 2 absence low
ettringite medium 720 OA

Unhydrated cement medium strong double 0.376
Ca (QH>2 medium 370R high
•ttsingite weak 7500A

Leachability
Values


-


-


low

high


 cement structure  and not chemically
 stabilized to the extent observed
 for zinc.  Mobilization of Hg
 leachability of the  fixed product
 is high and probably dependent on
 the permeability  of  the solidified
 product.

     The use of SEM has elucidated
 in what form this leaching fluid
 acts on the cementitious material
 (e.g.  Figures 2,  3  and 4).  In an
 unleached OPC/silicate sample with
 the simulated metal  waste, normal
 hydration products of C-S-H, C-H,
 calcium aluminate hydrates (: Xt and
 Afm phases) and unhydrated cement
 grains together with calcium sili-
 cate gel were observable.  In com-
uarison with OPC/silicate without
 metal addition, increased growth of
 the Aft phase with less C-S-H
 (Mostly Type I) was  noticeable.
 The SEM study showed that the most
TABLE 2. SEMI-QUANTITATIVE XRD DATA
   Sample
                               Relative

                               Int«n»lty*
 A 50 g OPC

   12 Bl KB.
 B 50 g OPC
   12 Kl N«2Si03
                     C-H
                               2.45
                    bellte (C2S)  1.03

                    •lite  {C3SJ  0.87

                    C-B        1.64
   200 al 2000 ppct Hg,Zn  belite (C^S)  1.16

                    •Xite (CjS)   0.95



 * normaliaed to HgCOH)
                                     342

-------
   -  0-14 r
    e»
   -E 0-12 -
    •g 010 -
    JJ
    6 D oe-
    § 004-
    I 0-021-
                          I*)
7500   3700    1500   750    370
      08
      0-6
      0-i
   §0.2
   1
                                          1SO
"n"
                                                i
                                               37
—T~
 15
"rT
                                                        Pore rotJiui nin
                                                                          3-7
                                                                         1C!
                                                                          IB)
7500  3700    1500   750   370
                                          150    75     37       15
                                                  Pert rediu* nm
                    7-5
If
i i
*
* »
i:
i;
; j
-
-

-
-

-
™
-
nm mo noo »>» m no n r »
Swpl* *•
•
s
» •
•
1 *
* I
hi J"
r
-
—
-
—
-
-
]_, _
NlrTT "i
TI it noc STDD two rMtTD tsonif nti»
mm fNp* *•«>•«» *»
       MD  no  in
       Siopl* e
Figure  1. Cumulative pore volume and pore-*.M.ze distribution.
                                       343

-------
Figure 2.  Micrograph showing pre-leached sample with long rods of
           ettringite, C-S-H, calcium silicate gel.  Corresponding
           EDAX analysis showing major peaks at 1.74 and 3.69 ev
           (silicon and calcium respectively - more Ca than Si).
Figure 3.  Micrograph of 1-day leached sample showing a grain with
           ettringite crystals and C-S-H.  The structure of C-S-H is
           less defined.  Sample still contains more Ca than Si.
 Figure 4.  Micrograph of 5-day leached sample showing smooth hydrolysed
            surface of grain and areas of gel-like morphology.  EDAX
            analysis indicates sample contains more Si than Ca.
                                344

-------
easily hydrolysed  structure was the
C-S-H phase which  after the 3  day
leaching period was  no  longer
observable.  However Zn and Hg
leachate concentrations did not
change appreciably which indicates
that C-S-H is unlikely  to be
involved in the fixation mecha-
nisms .

    Further leaching hydrolysed the
matrix and was associated with con-
tinued Ca removal  as demonstrated
by the EDAX analysis.   Possible
sources of Ca are  AFt and Mm,
calcium silicate gel, C-H and
unhydrated cement  grains.  After 3
days, less Aft (the  most iden-
tifiable phase) and  Afm were obser-
vable with increased calcium
silicate gel type  structures.
Concentrations of  Si and Ca were
similar at this stage.   However,
the Aft phase was  no longer visible
after the 5 day leaching period and
this coincided with  the dramatic
rise in Zn and Hg  leachate con-
centrations which  occurred sub-
sequently.  This indicates that the
disappearance of this phase marks
the beginning of break  down of the
structures that "fix" the metal
though there is no direct evidence
to prove that this phase is
directly responsible for such fixa-
tion.  After this  phase was hydro-
lysed the cementitious  matrix has
been sufficiently  broken down for
the fixed waste material to be
easily leached.  This occurs after
approximately 55%  of Ca removal and
corresponds to a massive breakdown
of structure.

    Figure 5 and 6 demonstrate that
high Si/C ratios increase initial
strength {within a few  hours) but
that the final strength is more
dependent on the w/c ratio).  The
increase in w/c not  only increases
the total intruded volume but also
        60-1
        so-
        40-
       o>
       c
      §30-
       *
       >
        2O-
      O 10.
                    -i	r W/C
          0 0-2 0-4 0-6 08 1-0
Figure 5. Strength vs W/C  ratio.
    O-l
    2H
   o
   o
    1-
                          28d
     o   O-04 o-es o-oe o-o?  o-oe
        1-04 1-05 *O6 1-07  t-08   W/C
Figure 6. Strength vs Si/C and
          effective W/C ratios.
                                   345

-------
shifts the pore size distribution
to a large pore radii.  This  is
considered to be the most critical
factor in determining the mechani-
cal strength of a cementitious
system (5).  The role of sodium
silicate in accelerating the
setting of the product is crucial
in normal stabilization practice in
order to minimize runoff and
leaching of waste material during
the critical initial setting  stage.
The addition of sodium silicate
does not promote a significant
improvement in final strength which
is in accord with the findings of
Nelson and Young (6).

    Material costs contribute the
majority of the overall cost  of
solidification processes and  thus
to a waste disposer, the addition
of additives such as sodium sili-
cate which accelerate setting may
increase the volume of waste  that
can be treated for the same amount
of material.  However, such an
increase in the water content
results in reduced physical strength
which has important implications
for the disposal of solidified
wastes in landfill sites.  It must
be noted that the objective of
these processes is to reduce  both
leachability and permeability and
to improve compressive strength
with minimal material costs.

ACKNOWLEDGEMENTS

    One of us (CSP) wishes to
acknowledge the support of Wimpey
Waste Management and Wimpey
Laboratories.

REFERENCES

1.  Poon, C.S., C.J. Peters,  R.
    Perry and C. Knight, 1984,
    Assessing the leaching charac-
    teristics of stabilized toxic
    waste by the use of thin layer
    chromatography, Environ.
    Techno1. Lett., Vol. 5, pp.
    1-6.

2.  Poon, C.S., C.J. Peters and R.
    Perry, 1983, Use of stailiza-
    tion processes in the control
    of toxic wastes. Effluent and
    Water Treament J., Vol. 23, pp
    451-459.

3.  Tashiro, C. and S. Tatibana,
    1983, Bond strength between CjS
    paste and iron, copper or zinc
    wire and microstructure of
    interface.  Gem, and Concr.
    Res., Vol. 13, pp. 377-382.

4.  Malone, p.G., C.w. Jones, J.P.
    Burkel, 1984, Application of
    solidification/stabilization
    technology to electroplating
    wastes.  In Land Disposal of
    Hazardous Wastes. Proc. Annual
    Research Symposium (9th), Ft
    Mitchell, Kentucky,
    PB-84-11877.

5.  Ramachandran, V.S., R.F.
    Feldman and J.J. Beaudoin,
    1981, Concrete Science,
    Treatise onCurrentResearch,
    Heydon and Sons Ltd., London,
    UK.

6.  Nelson, J.A. and J.F. Young,
    1977, Addition of colloidal
    silicas and silicates to
    Portland cement paste.  Gem.
    Conor. Res», Vol. 7,
    pp. 277-282.
               Disclaimer

 The work described in this paper was
 not funded by the U.S. Environmental
 Protection Agency.  The contents do
 not necessarily reflect the views of
 the Agency and no official endorse-
 ment should be inferred.
                                   346

-------
SAMPLE
h* OK: *
H2°

B. GPC/


c. OIK:/
solution


D. QPC/
+ Hg
Solution

SEH
{ 1 day sample)
C-S-H
Ca (QH)_
ettringite
C-S-H
Cm (Otn 2
ettringite
Ca-silicate
C»S-H
Ca 2
ettringite

Unhydrated
Ca { OH ) »
ettringite
Powder XRD
day sample)
cement medium strong
strong
weak
cement medium strong
week

cement strong
absence
medium

cement raedium strong
medium
weak
ftorosimetry Total Pore Leachatoility
C? days sample) Volume Values
single 0.136
370ft
double 0.416
370A
7500&

single 0.684
low low
7200ft

double 0.376
370A high high
7500A
Ca-silicate gel  raasaivn
                                         347

-------
            SORBENT ASSISTED SOLIDIFICATION OF A HAZARDOUS WASTE
       Tommy E. Myers, Norman R. Francingues, Jr., Douglas W. Thompson
                      USAE Waterways Experiment Station
                            Vicksburg, MS  39180
                                     and
                               Donald 0. Hill
                        Mississippi State University
                        Mississippi State, MS  39762

                                  ABSTRACT

     Sorbent assisted solidification as discussed in this paper is a treat-
ment technique for hazardous wastes containing toxic metals.  The basis of
the technique is adsorption/ehemisorption of metals by a sorbent that is used
in conjunction with a solidification process to immobilize metal contaminants.
The sorbent-metal complex is thought to become incorporated (not simply
entrapped) into the crystalline matrix provided by solidification processing.

     Sorption isotherms and chemical leach tests were used to investigate the
capacity of various sorbents to seize and hold metal ions, specifically
copper ions.  The sorbents investigated were flyash, soil, and organosilane
conditioned flyash and soil.  Organosilanes are chelating agents that have
the ability to seize and hold metal ions.  Adsorption isotherms were run in
order to determine the ultimate capacity of the various sorbents for copper.
The Langmuir equation was used to model the adsorption process.  Desorption
isotherms were run in order to obtain distribution coefficients related to
the release of copper from solidified waste.

     The data show that N-(B-aminoethyl)-Y-aminopropyl-trimethoxysilane, a
commercially available organosilane, can be used to improve the adsorption
properties of soil, and that sorbent assisted solidification reduces copper
leaching.  With the proper development and application, sorbent assisted
solidification could provide the technology needed for improved land disposal
of solidified hazardous waste.
INTRODUCTION

     Solidification is a treatment
technology that is sometimes
applied to liquids and semi-solids
which are too toxic for biological
treatment, too low in energy value
and/or too corrosive for thermal
processing, and too dilute for
landfilling.  Solidification typ-
ically involves mixing a setting
agent(s) with a waste to form a
hard, durable product that is sub-
stantially insoluble in water and
in which the waste contaminants
are entrapped in the solidified
mass.  There are several commer-
cially available solidification
processing systems  in use  in  the
United States  (12).  The most common
setting agents are  Portland cement
and pozzolans such  as flyash, kiln
dust, lime, soluble silicates,
gypsum, and combinations of these
materials.  (Pozzolans are materials
other than Portland cement that have
cementious properties.)  Generic
descriptions of the commercially
available solidification processes
have been published by Malone and
Jones (11).

     Solidification typically pro-
vides three major advantages over raw
waste disposal| these are 1) removal
of free liquid, 2) development of
                                      348

-------
structural integrity, and 3) improved
contaminant isolation and containment
(11, 12, 14,).  Isolation and con-
tainment of hazardous constituents
are accomplished by waste entrapment
in a cemented matrix and by con-
version of waste constituents to less
soluble compounds (precipitation).
Unfortunately, these mechanisms do
not always prevent the leaching of
hazardous constituents.  The
effectiveness of the entrapment
mechanism depends on the permeability
and durability of the solidified pro-
duct.  Because waste constituents can
interfere with the setting reactions
responsible for the development of a
hardened mass, there are problems
with durability.  Insoluble products
from precipitation can be resolu-
bilized if the leaching conditions
are different from the conditions in
which precipitation took place.  In
particular, pH and oxidation-
reduction potentials can be altered
by percolating water to resolubilize
toxic metals.  In addition, not all
materials are insoluble under the pH
and oxidation—reduction conditions
in moist concrete or pozzolan.
Hence, contaminants that have been
simply entrapped or precipitated can
be leached from solidified waste in
varying degrees, depending on the
type of waste and the kind of addi-
tives used (14).

     Adsorption is one means by which
soluble metals can be removed from
contaminated aqueous systems
(2,3,7,8).  Since adsorption is
reversible, desorption will occur to
some extent depending on the relative
affinity of the contaminant for the
aqueous phase versus the sorbed
phase.  The thermodynamics of the
sorption system partitions the con-
taminant mass between aqueous and
adsorbed phases so that the con-
taminant is never all in one or the
other phase, and thus, cannot be
released all at one time.  Con-
sequently, the amount released and
especially the release rate is
reduced if the contaminant is
adsorbed to a solid phase, rather
than simply entrapped in a lattice
work as a soluble or potentially
soluble salt.

     Unfortunately, the solid matrix
provided by cement and pozzolan pro-
cessing has little or no sorption
potential.  However, if a sorbent
that becomes incorporated into the
crystalline matrix provided by solid-
ification is included in the process
formulation, then the pollutant
potential of the solidified waste
should be significantly reduced.

     The metal sorption properties
of materials can be improved by bond-
ing certain organosilanes to them
(9, 13).  Organosilanes are silicon
compounds derived from silane, SiH,.
As chelating agents some organosilanes
have the ability to seize metal ions
and sequester them from further
reactions.  Leyden and Luttrell (9)
used the metal chelating properties
of organosilanes to preconcentrate
dissolved metals prior to chemical
analysis by X-ray fluorescence.
Malone and Karn (13) reported the
usefulness of an organosilane-silica
gel sorbent in removing cadmium,
chromium, copper and zinc from con-
taminated wastewater.

PURPOSE

     The objective of this study was
to investigate the feasibility of
reducing the metal leaching potential
of solidified waste by conditioning
of selected solidification additives
with N~(g-aminoethyl)-Y-aminopropyl-
trimethoxysilane.

APPROACH

     The research approach consisted
of 1)  conducting adsorption isotherm
tests on organosilane-additive pre-
parations in order to determine the
sorption characteristics for copper
and 2) conducting desorption isotherm
                                    349

-------
tests on solidified waste prepared
with and without silane conditioning
of selected solidification additives
in order to obtain distribution coef-
ficients for copper release,

Waste Solidification

    A concentrated brine containing
approximately 12 percent by weight
chloride, 8 percent by weight organic
carbon, 17 percent by weight dis-
solved solids, 4040 mg/£ copper, and
various toxic substances such as
aldrin, arsenic, and cyanide at parts
per million levels was collected from
a hazardous waste impoundment for
study and testing.  The liquid was
solidified in 1 liter batches with
equal weights of soil, flyash, lime,
and waste.  This solidification pro-
cess was chosen for investigation
because it included two materials
with sorbent potential (soil and fly-
ash) .  The flyash was obtained from
a local power plant.  The ash had a
specific gravity of 2.07 and con-
tained 4,7 percent lime as CaO.  The
soil, also available locally, was a
sandy clay (CL by the Unified Soil
Classification System).  The solidi-
fied waste was cured at room tem-
perature for 1 days prior to testing.

Sorbent Preparation

    The preparation of sorbents
involved the bonding of
N-(8-aminoethyl)-Y~aminopropyl-
trimethoxysilane to either flyash or
soil.  The organosilane (Dow Z-6020)
was obtained from SCM Speciality
Chemicals, Gainesville, Florida.  The
bonding procedure adapted from Leyden
and Luttrell (9) incorporated the
following steps:

    _a_.  A 10% aqueous silane solution
was prepared by adding silane to
deionized-distilled water with
stirring.  The solution was acidified
to pH 5-6 by adding reagent grade
glacial acetic acid.  The pH was
checked with pH paper.  Plastic con-
tainers were used to avoid reaction
with glass.
                                   350
    b_.  One gram of either flyash or
soil was contacted with aqueous
silane on a mechanical shaker for
30 minutes at a liquid to solids
ratio of 1.5 ml of aqueous silane to
one gram of substrate.

    _c_.  The mixture was reacted at
70°C in a vented oven for 24 hours.
In one bonding procedure the loss of
water was controlled so that the mix-
ture was not allowed to dry.  In
another the mixture was taken to com-
plete dryness at 70°C.

    d_.  The sorbent preparations that
were taken to complete dryness were
washed with water to remove excess
silane and then dried at 40°C.

    _e_.  The sorbent preparations that
were not taken to complete dryness
at 70°C were washed with water to
remove excess silane and then air
dried in a hood at room temperature.

Adjs orp t ion I so therms

    Adsorption isotherms were run in
order to determine the ultimate
capacity of the various sorbents for
copper and to determine equilibrium
adsorption constants.  In these tests
one gram quantities of sorbent were
contacted on a mechanical shaker for
24 hours with 100 ml of liquid waste
in various dilutions.  Each mixture
was then filtered and analyzed for
copper.  Six dilutions of liquid
waste were used as follows;  1000/1,
100/1, 50/1, 10/1, 5/1, and 1/1 (no
dilution).  Blanks consisting of
sorbent and deionized water were run
with each adsorption isotherm test.
Liquid-solid separation was by filtra-
tion using Gelman No, 61631 glass
fiber filters.  Adsorption isotherms
were run on soil, soil with organo-
silane, flyash, and flyash with
organosilane.

Desorption Isotherms

    Desorption isotherms were run by
contacting solidified waste samples

-------
with deionized-distilled water on a
mechanical shaker for 24 hours in
liquid to solid ratios as follows:
50 ml:5g, 50 ml:2g, 50 ml:lg,
100 ml:lg and 100 ml:Q.5g.  The mix-
tures were filtered and analyzed.
Blanks consisting of deionized-
distilled water were included in each
set.  Liquid-solids separation was
by filtration using Gelman No. 61631
glass fiber filters.  Desorption iso-
therms were run on waste solidified
using soil without organosilane condi-
tioning and on waste solidified using
organosilane conditioned soil.

Chemical Analysis

    Isotherm samples (aqueous phase)
were analyzed for copper on a
directly-coupled plasma arc spectro-
photometer by the Analytical Labora-
tory Group (ALG), Environmental
Laboratory, USAE Waterways Experiment
Station, Vicksburg, MS.
the soil surface are forced into a
high collision probability by taking
the mixture to dryness.

RESULTS

Adsorption Isotherms

    In an isotherm test the amount
of contaminant removed is determined
as a function of the aqueous con-
centration at a constant temperature.
The resulting set of data is called
an adsorption isotherm.  From the
data a table of aqueous phase con-
centrations, C, and corresponding
sorbent phase concentrations, q» can
be prepared.

    The Langmuir equation is often
used to model adsorption processes
at equilibrium (15).  The Langmuir
equation is

        q - K. Q C/(l + K. C)    (1)
PROBLEMS ENCOUNTERED

    The most significant problem
encountered involved the
soil/organosilane bonding procedures.
When the soil organosilane mixture
was not taken to dryness, the sorbent
produced was inferior to that pro-
duced when the mixture was taken to
dryness.  This was indicated by
reduced adsorption coefficients as
discussed in the results section.
One possible explanation for this
relates to the collision frequency
between the silane molecules and
active hydroxyl sites on the soil
surface.  The reaction of organo-
silane with a substrate involves
hydrolysis of the methoxy groups,
polymerization by condensation,
hydrogen bonding between the con-
densed organosilane polymer, and
finally formation of a silicon-
oxygen bond (siloxane) between the
substrate and the silane (1).
Apparently the final step is not
accomplished until condensed organo-
silane polymer and active sites on
where
     q = Concentration of contaminant
         in the adsorbed phase, m/m
                                   5

     Q = Ultimate monolayer capacity
          of the sorbent, m/m
     C = Concentration of contaminant
         in the aqueous phase, m/L
    K. = Langmuir distribution
         coefficient, L /m
    m  = Mass of sorbent
     s
    The adsorption isotherm data
obtained in this study were analyzed
by least squares fitting of the data
to the linear form of equation (1)
below.
         C/q
l/(QKd)
C/Q
(2)
The coefficients 1/(QK.) and 1/Q were
determined by least squares analysis
and from these Q and K, were obtained.
These coefficients were then used to
produce the adsorption isotherms
shown in Figure 1.
                                    351

-------
      0       500      1000     1500
                 C, mg/K


               LEGEND

  (1);  SOIL
  (2);  SOIL/ORGANOSILANE TAKEN TO
        DRYNESS
  (3):  SOIL/ORGANOSILANE, WET
  (4):  FLYASH/ORGANOSILANE TAKEN
        TO DRYNESS
  (5):  FLYASH

Figure 1.  Adsorption Isotherms

    The curves show that con-
ditioning of the soil with organo-
silane enhanced the ultimate
adsorption capacity, Q.  (Q is the
value each curve asymptotically
approaches.)  On the basis of ulti-
mate adsorption capacities, the
organosilane conditioned sorbents
were superior to the unconditioned
sorbents, and the soil based
sorbents were superior to the flyash
based sorbents.  The adsorption
isotherm data also show that the
soil even without organosilane
conditioning is more than just a
filler in the solidification
process.  Copper is adsorbed by the
soil.

    The data also indicate that the
soil/organosilane bonding procedures
affects sorbent performance.  The
best copper adsorbent investigated
in this study, as indicated by the
isotherms shown in Figure 1, was the
soil/organosilane sorbent prepared
by taking the soil/organosilane mix-
ture to dryness.  Soil was generally
less effective than the
soil/organosilane sorbents, espe-
cially when the soil/organosilane
mixture was taken to dryness during
sorbent preparation.  The flyash
based sorbents were inferior to the
soil based sorbents.  The poor per-
formance of the flyash preparations
was probably due to the lime com-
ponent in the flyash.  Base
hydrolysis of the siloxane bond can
occur under certain conditions (1).

Desorption Isotherms

    Desorption isotherms can be used
to provide fundamental information
on the interactions between ground-
water and contaminated soils and
sediments (4, 5, 16).  If the sorp-
tion processes of adsorption and
desorption have taken place under
identical conditions, then the
desorption of a contaminant back into
the aqueous phase should proceed down
the adsorption isotherm and follow
it exactly.  However, the conditions
under which, adsorption takes place
is usually significantly different
from those under which desorption
isotherms are developed.  If the
sorption systems differ significantly
in pH, ionic strength, and chemical
activity, the desorption process will
not simply be a reversal of the
adsorption process.

    Jeffe and Ferrar (6) suggested
the following simple mass action
desorption model:
dC/dt
                         Kq
(3)
where K| is the adsorption rate and
K_ is tne desorption rate.

For steady state conditions dC/dt =
0, and equation 3 becomes equation 4
below:
                                     352

-------
                                            4 p
              q-K' C
(4)
where Kt = K!/K
       a    1
Equation 4 describes the
relationship between sorbed and
aqueous phase concentration for a
desorption-dominated equilibrium by
a simple distribution coefficient,
K'.  Each value of contaminant
loading in the solid phase, q,
supports a unique aqueous phase
concentration, C, that at equilibrium
is directly proportional to q by the
distribution coefficient, K'.  In
terms of leaching potential, the
higher the distribution coefficient,
Kj, the lower the aqueous phase con-
centration, C, that a given sorbent
loading, q, will support.

    The desorption isotherm data are
presented in Figure 2.  Sorbed versus
aqueous phase concentrations are
plotted for waste solidified using
soil without organosilane condition-
ing and for waste solidified using
soil with organosilane conditioning.
The desorption isotherm data fit the
linear model of q versus C presented
in equation (4).  The desorption
isotherms show that sorbent assisted
solidification using organosilane
conditioned soil produced a product
with a higher Kl than did sorbent
assisted solidification using soil
alone.  The affinity of copper for
the organosilane reduced the amount
of copper in the aqueous phase.  The
organosilane used in the desorption
isotherm test was not prepared by
taking the soil/organosilane mixture
to dryness.  The adsorption isotherms
in Figure 1 indicate that had sorbent
preparation involved taking the
soil/organosilane mixture to dryness,
the distribution coefficient would
have been even higher.  The problem
with bonding procedures was not
recognized early enough in the test-
ing program to include sorbents pre-
pared by taking the mixture to
dryness in the desorption isotherm
testing.
                                    353
                                                           0.6829^'? °'3562
                     l.  I   I	L
                                   LEGEND

                                 SOIL/ORGANOSILANE
                               I  SOIL
                               	1,  I	1	1
                     3456
                         C, mg/8
                                7  8  9  10
         Figure 2.  Desorption Isotherms

         PotentialFor Field Application

             Several important aspects of
         field application were not addressed
         in this laboratory study of sorbent
         assisted solidification using organo-
         silane.  Topics beyond the scope of
         the investigation include scale-up
         factors, organosilane compatibility
         with alternative binder/substrate
         systems, long-term stability of £he
         solidified product, and engineering
         economy.  Additional testing and
         evaluation is needed before organo-
         silane assisted solidification can
         be applied in the field.

             In addition, organosilanes are
         produced as speciality chemicals that
         are expensive in small quantities.
         Even with a significant cost break-
         through between laboratory and bulk
         quantities, full-scale application
         of sorbent assisted solidification
         using organosilane may be limited to
         small volumes of highly contaminated
         metal wastes that would otherwise
         pose a serious environmental hazard
         if landfilled.

         CONCLUSIONS

             Sorbent assisted solidification
         using organosilane is an innovative
         treatment technology that could be
         applied, depending on technical and
         economic factors associated with
         full-scale application, to highly
         contaminated metal wastes prior to

-------
land disposal.  Specific conclusions    3.
drawn from the results of the study
are as follows:

1.  Organosilane, specifically
N-(0-aminoethyl)-Y-aminopropyl-
trimethoxysilane, can be used to
improve the natural adsorptive capa-    4.
city of soil for copper.

2.  Organosilane, specifically
N-(0-aminoethyl)-y-aminopropyl-
trimethoxysilane, can be used to
reduce the copper leaching potential
of solidified waste when Organosilane
conditioned soil is used as a solidi-
fication additive.
                                        5.
3.  Soil/organosilane bonding pro-
cedures affect sorbent performance.
When the soil/organosilane mixture
is not taken to dryness during
preparation, the sorbent produced is
inferior to that produced when the
mixture is taken to dryness.            6.

ACKNOWLEDGEMENTS

    The tests described and the
resulting data presented herein were    7.
obtained from research conducted
under the Department of the Army In-
House Laboratory Independent
Research (ILIR) Program, 1LIR project
No. 4A161101A91D, by the US Army
Engineer Waterways Experiment Sta-
tion, Vicksburg, MS  39180.             8.

REFERENCES

1.   Arkles, B.  1977.  "Techniques
     for Silylation," Chemtech,
     7:713-717.
                                        9.
2.   fuller, W. H., Amoozegar-Fard,
     A., Niebla, E. E., and
     Boyle, M.  1980.  "Influence of
     Leachate Quality on Soil
     Attenuation of Metals."  Proc.
     Sixth Annual Res. Symp. on
     Disp. on Haz. Wastes,
     EPA-600/9-80-010, U. S. Environ-
     mental Protection Agency,
     Cincinnati, OH  45268.
Griffin, R. A., et al.  1976.
"Attenuation of Pollutants in
Landfill Leachate by Clay
Minerals."  Envir. Geology
Notes No. 78, Illinois Geo-
logical Survey, Urbanna, IL.

Houle, M. J. and Long, D. E.
1980.  "Interpreting Results
from Serial Batch Extraction
Tests of Wastes and Soils."
Proc. Sixth Ann. Res. Symp.,
Chicago, IL,
EPA-600/9-80-010, US Environ-
mental Protection Agency,
Cincinnati, OH  45268.

Isaacson, P. J. and Frink, C. R.
1984.  "Nonreversible Sorption
of Phenolic Compounds by
sediment Fractions:  The Role of
Sediment Organic Matter," Envir.
Sci. &Tech.. 18:43-48.

Jaffe, P. R. and Ferrara, R. A.
1983.  "Desorption Kinetics in
Modeling of Toxic Chemicals," _J._
of Env. Eng.. 109:857-867.

Korte, N. E., Skopp, J., Fuller,
¥, H., Niebla, E. E., and Alesii,
B. A.  1976.  "Trace Element Move-
ment in Soil:  Influence of Soil
Physical and Chemical Properties,"
Soil Sci.. 122:350-359.

Korte, N. E., Skopp, J., Niebla,
E. E., and Fuller, W. H.  1975.
"A Baseline Study on Trace Metal
Elution From Diverse Soil Types,"
Water, Air and Soil Pollut.,
5:149-156.

Leyden, D. E. and Luttrell,
G. H.  1975.  "Preconcentration
of Trace Metals Using Chelating
Groups Immobilized via
Silylation," Anal. Chem., 47:9,
1612-1617.
                                    354

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10.  Maloch, J. L., Averett, D.  E,
     and Bartos, M. J., Jr.   1976.
     Pollutant Potential of  Raw and
     Chemically Fixed Hazardous
     Industrial Wastes and Flue Gas
     Desulfurization Sludges.
     Interim Report.  EPA-600/2-76-
     182, U. S. Environmental Pro-
     tection Agency, Cincinnati, OH
     45268.

11.  Malone, P. G. and Jones, L. W.
     1979.  Survey of
     Solidification/Stabilization
     Technology for Hazardous
     Industrial Wastes.  EPA-600/2-
     79-056, U, S. Environmental Pro-
     tection Agency, Cincinnati, OH
     45268.

12.  Malone, P. G., Jones, L. W., and
     Larson, R. J.  1980. Guide to
     the Disposal of Chemically
     Stabilized and Solidified Waste.
     SW-872, U. S. Environmental Pro-
     tection Agency, Cincinnati, OH
     45268.

13.  Malone, P. G. and Karn, R.  A.
     1982.  Toxic Metal Removal From
     Electroplating Wastewater Using
     Silylated Silica Gel, Misc. Paper
     EL-82-3, USAE Waterways Experi-
     ment Station, Vieksburg, MS
     39180.

14.  Malone, P. G. and Larson, R. C.
     1983.  "Scientific Basis of
     Hazardous Waste Immobilization,"
     Hazardous and Industrial Solid
     Waste Testing.  Second  Symposium,
     STP 805, ASTM, Philadelphia, PA
     19103.

15.  Metcalf and Eddy, Inc.   1979
     WastewaterEngineering;  Treat-
     ment, Disposal, Reuse,  2nd ed.
     McGraw Hill Book Co., New York,
     NY.
16.  Myers, T. E. and D, 0. Hill.
     1985.  "Extrapolation of Labora-
     tory Leach Data to the Field
     Situation," Paper presented to
     the Annual Meeting Mississippi
     Academy of Science, 21 Feb 1985,
     Jackson, MS.
                 Disclaimer

   The work described  1n  this  paper was
   not funded by  the U.S.  Environmental
   Protection Agency.   The contents do
   not necessarily  reflect the views of
   the Agency and no official  endorse-
   ment should be Inferred.
                                     355

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           THE EFFECT OF PARTICLE SIZE ON THE.LEACHING OF HEAVY METALS
                        FROM STABILIZED/SOLIDIFIED WASTES

                        Todd M, Brown and Paul L. Bishop
                           University of New Hampshire
                           Durham, New Hampshire 03824

                                    ABSTRACT

     Stabilization/solidification of hazardous liquids and sludges by a
variety of techniques has been investigated as a method of treatment that
will bind hazardous materials in a form that minimizes adverse effects on
the environment after landfilling.  One method of stabilization/solidifi-
cation that has been investigated is the combination of the waste with
Portland cement to form a cement paste.  The structure of the paste re-
sists chemical attack, making the technique attractive as a disposal alter-
native for heavy metal sludges.  This paper presents results concerning the
effect of particle size on the leaching pattern of metals from these
wastes.  Both batch and upflow column leaching tests were investigated.

     The results indicate that in the early part of the column test, small
particles at the bottom of the column release both metals and alkalinity.
As the leachant moves upward through the column, the alkalinity leached
neutralizes the acid leachant causing the pH to rise.  This forces the
metals that were leached below to either be re-precipitated or sorbed onto
a particle surface.  As the leaching zone rises through the column, metals
are concentrated near the top of the column.  When the leaching zone breaks
through the top of the column, metal concentrations in the leachate increase
rapidly.  As the extraction continues beyond this point, the concentrations
of metals in the leachate gradually decline.  In the columns packed with
larger particles, however, the rate of alkalinity release from the particles
is not rapid enough to neutralize all the acid in the leachant by the time
the leachant reaches the top of the column.  This results in an immediate
release of metals into the leachate. As extraction continues, the rate of
metals release gradually increases, indicating that the alkalinity that is
being released is exposing  more surface area to the acid leachant.

INTRODUCTION AND PURPOSE                    One method of disposing of
                                       some of these wastes.in a more en-
     The disposal of hazardous         vironmentally acceptable fashion is
waste on land has almost universally   to stabilize/solidify them before
led to environmental problems due      landfilling.  In this process the
to leaching of waste constituents      waste sludges are combined with
into groundwater.  Properly designed,  various additives that both chemically
constructed and managed "secure"       bind and physically solidify the
chemical landfills, in which clay      hazardous materials, thus making them
or synthetic membrane liners and       less, susceptible to leaching.  Stabi-
leachate collection systems are        11 zed/solidified wastes may still
used, can delay the onset of ground-   leach with time, but the rate of
water contamination, but these         leaching should be very low so that
liners may eventually break down.      the pollutants will disperse into the


                                      356

-------
environment without adverse con-
sequences. 	

     One method of stabilization/
solidification which has been stud-
ied extensively at the University
of New Hampshire consists of the
combination of inorganic waste
sludges with port!and cement to form
a cement paste.  The structure of
the Solidified paste resists physical
attack and gives the product strength
and durability, and the highly
alkaline nature of the material
resists chemical attack, making the
technique attractive as a disposal
alternative for heavy metal sludges.

     The environmental acceptability
of hazardous wastes is partially
determined by use of the U.S. En-
vironmental Protection Agency Ex-
traction Procedure (EP) test, in
which the waste is contacted with a
mild acetic acid leachant for 24
hours, after which the leachant is
analyzed for specific metals which
may have leached.  This test proce-
dure is not valid, though, for
stabilized/solidified wastes because
the alkalinity present in the waste
quickly neutralizes all of the acid
present so that leaching occurs
under highly alkaline conditions
rather than acific ones, and because
the solidified waste is a monolithic
mass rather than in particulate
form.  These properties are bene-
ficial from the standpoint of environ-
mental protection as they greatly
decrease the tendency of the material
to leach, but.they do cause problems.
relative to determining the.actual
Teachability of:the waste.  Diffi-
culties associated with the al kali.ne
nature of the waste are addressed
elsewhere U»3»4,7}.  This paper is
concerned with, the effect of part-
icle size on leaching properties of
solidified/stabi 1i zed hazardous
wastes.
     Stabi 1 tzied/s.olIdifled wastes
are placed,in the environment as
monolithic blocks. With low •perme-
abilities.  Over.time».tfi.Qugh, these
blocks may be physi cally and chemi =
cally attacked in such a way as to
create smaller particles. It has
been:proposed that the amount of
metals, leached:should be directly
proportional to the surface area
available for leaching (5,6,8).
Early research at the University of
New Hampshire, though, found that
smaller particles leached less metals
than larger particles (2).

     The purpose of this paper is to
evaluate this phenomenon and to ex-
plain how particle size affects the
release pattern of heavy metals from
stabilized/solidified hazardous
wastes during the conduct of both
batch and column extraction tests.

APPROACH

Synthetic hazardous waste sludges wfere
prepared in the laboratory, solidified/
stabilized with type II port!and
cement, ground to specified size
ranges, and the ground material sub-
jected to various leaching tests.
Batch extractions were performed us-
ing both the U.S. EPA EP Toxicity
test procedure (9) and a modified
test developed by Bishop et al. (2).
Column extraction test procedures
were developed by the authors.

     The sludges were formulated to
contain Q.04 moles/I each of cad-
mium, chromium, and lead.  Metals
were added as chromium chloride,
cadmium nitrate and lead nitrate and
converted to thei r hydroxide precipi tate
forms in the sludge by neutralization
of the solution to pH 8.5 with sodium
hydroxide. .The sludges were mixed
with type!! Portland cement to form
cement pastes with water/cement (w/c)
                                     357

-------
ratios of Q.5 and 1.0 using ASTM
procedure C30582.  The freshly
mixed pastes were placed in 3,8 cm
diameter by 7.6 cm tall PVC cy-
linders and allowed to set for
24 to 48 hours at 100% humidity
before they were removed from
their molds and returned to the
100% humidity environment.

     Cylinders to be used in the
extraction tests were broken and
pulverized with a mortar and
pestle.  The particles were
mechanically sieved and the
resulting particle sizes were
collected for testing.  Particle
size ranges used were 4.8-9.5 mm
(large particles) and 0.3-0.6 mm
(small particles).

      Batch extraction of the
particle fractions were performed
using the U.S. EPA-EP toxicity
test and a modified version
developed in our laboratories.
The two main differences in
these tests are: 1) The EP-
toxicity test uses 0.5N acetic
acid to enhance leaching while
the modified test use 17.4 N
glacial acetic acid, and 2) the
EP-toxicity test limits the
amount of acid added to keep the
pH at 5.0 +. 0.5 to 40 ml so that
the actual pH of the leaching
medium may be well above pH 5.0,
while there was no limit to how
much 17.4 N acetic acid could be
added to keep the pH at 5.0 +
0.5 in the modified test.  TRe
samples were placed on a shaker
table in a contolled temperature
room (20 C); the pH was monitored
and adjusted over a 24 hour
period as specified in the EP-
toxicity test procedure (9).

     The samples were removed
from the shaker table after 24
hours and filtered through a
0.45 vm filter. Metal analysis
was performed on the filtered
leachate by atomic absorption
spectrophotometry.

     Column leaching tests were
performed in the upflow mode.  The
columns were 46 mm diameter by 139
mm high Buchner type funnels that
were modified by a glassblower.  The
modifications included addition of a
side arm for effluent flow and taper-
ing the neck of the funnel to a pi pet-
like tip to accomodate narrow bore
tubing.

     All leachant flows were set at
0.2 ml/min.  Acid strengths of Q.05N
and 0.1N were used to create acid
fluxes of 1.0 and 2.0 meq/g sample/
day.  Leachates from the columns
were collected in 500 ml Erlenmeyer
flasks.  Leachate was collected every
24 hours, pressure filtered through a
0.45 ym filter, and the metal concen-
trations determined. The alkalinity
of the leachate was measured with a
recording titrator.

RESULTS AND DISCUSSION

     The results of batch leaching
tests for cadmium using the modified
EP procedure are presented in Figure
1.  Leachate lead concentrations
followed similar patterns. Leachate
metal concentrations in the EPA-EP
extracts were much lower, being at or
near minimum detection limits.  The
pH of these leachates were generally
between 10 and 11, considerably
higher than in the modified EP leach-
ates.  Thus, little of the metal in
the samples subjected to the EPA-EP
test was in a soluble form.
                                     358

-------
                                       ate metal  concentrations.
 100
i
o
 O.I I	
   O.OOI
             O.OI         O.I
            PARTICLE SIZE (IncMl)
 Figure 1.  Effect of Particle Size,
 Water: Cement Ratio and Sludge Con-
 centration on Cadmium Leaching -
 Batch Tests,
     Column leaching tests were
then developed to investigate this
phenomenon further.  It was observed
that as the extractions proceeded,
the small size particles that were
exposed, to. the .'acid turned from their
natural cement-gray color to a dark
gray and then to an orangish-brown
color and finally to a white color.
By observing the boundary between the
cement gray and the dark gray, the
progression of the acid attack could
be closely monitored. The larger
particles also turned an orangish
brown, but never turned to the white
color of the smaller particles.  The
progression of acid attack in the
columns containing large particles
was faster than in columns with small
particles.  All the large particles
turned  to an orangish brown color
in  the  first two days of extraction,
while  the  color change of the small
particles  was  a slower progression  up
through  the column.
      It was initially hypothesized
 that as the particle size decreased,
 thereby increasing the surface area,
 the magnitude of metal leaching would
 increase.  Surprisingly, the reverse
 of this was found to occur.  This led
 to the question as to whether the
 heavy metals are actually "locked up"
 in the smaller particles or whether
 some other property of the smaller
 particles enhances metal binding.
 Total digestions were performed on
 representative particles of each size
 range using boiling nitric acid.
 These indicated that heavy metal
 concentrations were:the same in all
 particle sizes before leaching.  One
 explanation for these results is that
 the heavy metals are bound to the
 particles by sorption mechanisms.
 Increased surface areas occurring in
 the smaller particles would cause
 greater  ion exchange and adsorption
 of heavy metals and thus lower  leach-
      The  difference  in  behavior  of
 the  large and  small  particles may be
 explained by the difference in avail-
 able surface area.   The small particles
 have more available  surface to  leach
 alkaline  species from,  neutralizing
 the  acidity of the  leachant before  it
 reaches  the particles near the  top  of
 the  column. The large  particles, on
 the  other hand, do  not  have as much
 available surface alkalinity and the
.acid attacks the entire column without
 being completely neutralized.   In all
 cases, the time of  break through of
 the  orange front at the surface  of
 the  layer of particles  corresponded
 to the time when the pH of the  leach-
 ate  dropped below 6, and to the time
 When the ratio of total alkalinity
 leached from the particles to the
 total amount of acid passed through
 the column fell below 1.0.  This is
 the point at which the acid being
                                    359

-------
added is no longer being  com-
pletely neutralized by  the  alka-
linity of the cement paste.

     Figure 2 shows the concen-
trations of metals leached  from  the
particles as a function of  the
total amount of acid passed through
the column for one experimental
run.  The release of metals into
the leachate water leaving  the
columns containing small  particles
did not occur until after addition
of approximately 8 meq  acid/g waste.
   2,3
   Z.O
  X 0,3
      A Lor 54 porllcw,C4
      * Lorn* parlkM,Cr
      & Smol pattid»,Cd°
      O Srocfl portid»,er
               10    IS    20
               TOTAL ACID (nwq/g)
Figure 2. Metals  Leached as a
Function of Total  Acid Added -
Column Tests.

Metal concentrations  in the leachate
then increased  rapidly for a time
before falling  back to lower con-
centrations. The  rapid rise in
concentrations  corresponded to the
time when the ratio of alkalinity
leached/ meq of acid  passed through
the column fell below 1.0 (Figure
3), indicating  the time when the
alkalinity  leached from the solid
could no longer neutralize all of
the acid being  added.  The period
of declining concentrations is
probably due to a bulk diffusion
limited release, which would  pre-
dict similar declining rates  of
release as time progresses  since
it takes more time for ions to
e 0.8
                                        "0.6
                                        jO.4
                o Small partlcta— Ratio
                a Small particl*— gH
                * Lorgt partid* ~Ro1lo
                » Latg» patUctt—pH
         5     IO     19     20    28
             TOTAL ACID (m»q/g)

Figure 3. Alkalinity Leached to  Acid
Added Ratios - Column Tests.

diffuse from further within  the
particle.

     The metal leaching patterns for
large particles, shown  in  Figure 2,
were quite different than  those  for
the small particles. The release of
metals from the large particles  began
immediately and concentrations  in-
creased throughout the  test, with only
a slight decrease near  the end of the
test.  Cadmium appeared to
more readily than chromium
This rise in metal release
direct function of surface
for leaching. As alkalinity  is  leached
from the particles, more pores  are
opened, leading to additional surface
area available for acid attack  and
metals release.  Alkalinity  leached/
acid added ratios were  always below
1,0 (see Figure 3} indicating that
sufficient alkalinity  to neutralize
acid was not immediately available to
the leachant due to  the reduced surface
area provided by larger particles.  As
                            leach much
                            or lead.
                            could be a
                            area available
                                      360

-------
a result, the pH of the  leachant
remained low, allowing any metals
leached to remain in solution.

     Figure 4 shows curves of alka-
linity leached as a function of acid
          5      IO     19
           TOTAL ACID (|MD/|)
Figure 4. Alkalinity Leached  Funct-
ion of Total Acid Added - Column
Tests.

passed through the column for both
small and large particle columns.
The rate of alkalinity leaching from
the large particles dropped as the
extraction progressed, but not as
rapidly as that from the small part-
icles.  This indicates that the
available surface area for leaching
was increasing at a decreasing rate,
which corresponds with the metal
releases.

     These results are in general
agreement with those presented earl-
ier for batch leaching tests, where
it was found that smaller particles.
leached less metals than larger
particles, particularly for low
acid doses which would correspond
to conditions in the batch tests.
However, plots of cumulative metals
leached as a function of total acid
addition (Figure 5) indicate  that
eventually cumulative metals  leach-
ed from the small•particles.be-
comes greater than from the large
particles.  This generally"occurs
at the point at which the acid
flowing by the small particles is
no longer totally neutralized and
leachate pH drops.
                                              Larg* parflclf*, Cd

                                             • large pgrticlt*, Cr

                                             * Larga particle*, PS

                                              Smell ptjrllcltl, Cd

                                             o Small partlclu, Cr

                                             D Small portion*. Pb
Figure 5,  Cumulative Metal  Leached
as a Function of Total Acid  Added  -
Column Tests.

     Chromium and lead were  leached
in much higher concentrations from
the small particles than from the
large particles.  The cement mat-
rix in the small particles was
probably breaking down due to the  lack
of alkaline species available to neu-
tralize the acids containing them.   If
the chromium and lead were bound into
the cement matrix, the higher rate of
leaching from the small particles  would
be explained.  To determine  whether  the
cement matrix of the small particles was
actually being broken down at a higher
rate than for the larger particles,
representative samples were  analyz-
ed for silicon.  These analyes
showed that.the smaller particles
released three times as much sili-
con as the large particles after
the initial alkalinity was reduced.
                                     361

-------
     Figure 6 shows a pC-pH dia-
gram for hydroxides for lead, cad-
mium, and chromium,  Hicjher pC
Values mean less, metal in tfie
soluble phase since pC is the nega-
tive logarithm of the concentration.
                B
                PH
Figure 6.  pC-pH Diagram for solu-
bility of Metal Hydroxides.

The high pH of the paste as it is
being mixed (around pH 12) causes
lead and chromium to form soluble
hydroxide complexes.  Availability
of these anions in solution allows
them to participate in the formation
reactions, possibly much like
aluminum.  The insoluble cadmium hy-
droxide is not available to take part
in solution reactions and is trapped
in the pores as the solid is formed.
This could explain why Teachability
of chromium and lead appears to be
dependent on the dissolution of the
silicate matrix while release of
cadmium seems to occur as pores are
opened.  Although the curve shows
that only about 10% of the chromium
and lead orginally present would
form the anionic hydroxide complex,
more could be formed as that init-
ially present is depleted by parti-
cipating in solid formation re-
actions.  The hypothesis cannot
rule out the possiblity of an
encapsulation type reaction where
lead and chromium hydroxide are
 surrounded  by  the  silicate fibrils
.that'are  formed.   However, there is
 no  apparent reason.why,encapsulation
 would.occur for chromium and  lead
 and not for cadmium.

      The  results of the column
 tests indicate that cadmium is
 primarily bound into  the solid
 matrix  by surface  related mechanisms
 such as ion exchange  and adsorption.
.The lead  and chromium, however, are
 primarily bound into  the silicate
 matrix  of the  paste.

      The  size  of the  particles
 being leached  controls the extent
 to  which  acidic leachant is neutraliz-
 ed  in the beginning of the extract!on,
 with small  particles  having more
 alkalinity immediately available.
 When the  leachant  is  neutralized,
 metal concentrations  in the leachate
 are low.   However, when the leachate
 can no  longer  be neutralized  be-
 cause much of  the  available alka-
 linity  has been  leached, the  metal
 concentrations in  the leachate  in-
 crease.  The small particle size
 leached more metal than the larger
 size, but release  was delayed by
 the particles' ability  to  neutralize
 the leachant before  it  left the
 column  in the  early  part of the
 extraction.

      The  small particles  in the
 lower portions of  the column  began
 to dissolve early  in the  extraction,
 as buffering capacity of  these
 particles was quickly reduced.   The
 rapid reduction of buffering  capa-
 city was  due to immediate  avail-
 ability of alkaline species  from
 the  large exposed  surface  area.
 This dissolution of the small part-
 .ides.led to the release of lead
 and  chromium in higher concen-
 trations than were observed in
 the  large particle leachates  where
 alkaline species available from
 deeper within the particles pre-
                                   362

-------
vented dissolution from oecuring
as rapidly.  Final cumulative
cadmium concentrations and total
alkalinity 1 ea.ched, f rom large'and
small particles were similar. -The
similarity in alkalinity leached
indicates that approximately the
same amount of surface area Bad
been exposed to th".e leachant by
the end of the extraction.  This.
led to nearly equal amounts of
cadmium leached, since the cadmium
is primarily bound to the surface
or held as insoluble hydroxides in
the pores.

     It is apparent that batch leach-
ing tests or short duration column
tests do not provide a true indi-
cation of the leaching potential of
solidified/stabilized hazardous
wastes or of the metal binding
mechanisms present.  It is only
through the use of longterm column
leaching tests or possibly with
multiple extraction batch leaching
tests that meaningful data can be
obtained.

ACKNOWLEDGMENTS

     This research was supported in
part by the Office of Sea Grant,
National Oceanic and Atmospheric
Administration, and by New Hampshire
Division of Public Health Services,
Office of Waste Management.

REFERENCES

1.   Bishop, P. and D. Gress, 1982,
Leaching from Stabilized/Solidified
Hazardous Wastes., Proceedings, 1982
National Conference on Environmental
Engineering, Minneapolis, MN, 423-429;-

2.  Bishop, P., S. Ransom and D.
gress, 1983, Fixation Mechanisms in
Solidification/Stabilization of In-
organic Hazardous Wastes, Proceedings,
38th Purdue Industrial Waste Confer-
ence, .West Lafayette, IN, 473-480.

3.   Brown, T.:and p. Bishop, T985,
Alkal i nity;Releas.es..and _th.e Leach.i.ng
of Heavy- Metals from Stabilized/
Sol i di fied Was tes. Proceedings, Fifth
International Conference on Chemistry
for Protection of the Environment,
Leuven, Belgium.     •

4.  Brown, T.» W. Shively, P. Bishop
and D.  Gress, 1985, Use of.an Upflow
Column Leaching Test to study the Re-
lease Patterns of Heavy Metals from
Stabilized/Solidified Heavy Metal
Sludges, Proceedings, International
Symposium on Industrial and Hazard-
ous Waste, Alexandria, Egypt.

5.   Ham, R., M. Anderson, R. Steg-
mann and R. Stanforth, 1979, Back-
ground Study on the Development of
a Standard Leaching Test, EPA 600/
2-79-109, USEPA, Cincinnati,  OH.

6.   Lowenbach, W., 1978, Compilation
and Evaluation of Leaching Test Me-
thods, EPA 600/2-78-095, USEPA, Cin-
cinnati, OH.

7.   Shively, W., T. Brown, P. Bishop
and D. Gress, Heavy Metal Binding
Mechanisms in the Stabilization/
Solidification Hazardous Waste
Treatment Process 1984, Industrial
Waste, .57th Annual Conference of the
Water Pollution Control Federation,
New Orleans, LA.

8.   Thompson, D., 1979, Elutriate
Test Evaluation of Chemically
Stabilized Waste Materials, EPA
6QQ/2-79-154, USEPA, Cincinnati,, OH,

9.   U.S. Environmental Protection
Agency, T98Q, Hazardous Waste and
Consolidated.permit Regulations,
Federal Register. Vol. 45, No. 98,
33Q63-33285, May 19, I960.
The work described In this paper was not funded by the U.S. Environmental
Protection Agency.  The contents do not necessarily reflect the views of the
Agency and no official endorsement should be inferred.
                                    363

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                     DEVELOPMENT OF A METHOD FOR MEASURING
                          THE FREEZE-THAW RESISTANCE OF
                          SOLIDIFIED/STABILIZED WASTES

                            P.  Hannak,  and A.  3.  Li em
                          Alberta Environmental Centre
                           Vegreville,  Alberta, Canada
                                     TOB 4LO
                                    ABSTRACT

    A description is given of the development of a method for measuring the
freeze-thaw resistance of solidified/stabilized wastes.  Various features of
the existing ASTM methods have been adopted, such as the use of weight loss as
a measure of freeze-thaw resistance, and the media and durations of the
freezing and thawing phases.  New features are also introduced, including
loose particulate removal method and the use of control specimens to isolate
the effect of freezing and thawing.

    The initial results show that a relative standard deviation (ratio of
standard deviation to mean) of better than 11% could be obtained in the
cumulative weight loss measurements.  The method was applied to a synthetic
waste treated with five different additives that are commonly used in
solidification/stabilization processes.  Differences in freeze-thaw resistance
could be readily observed, thus indicating the potential use of the method for
comparing different processes on the basis of freeze-thaw resistance.

    Modification to simplify the method are suggested, and further tests are
planned to assess its applicability to a wide variety of wastes treated by
commercially used processes.  Adoption of the method for measuring wet-dry
resistance will also be assessed.
INTRODUCTION

    Leaching of contaminants from
land-disposed  wastes is a well
recognized environmental concern.
To reduce such leaching and its
consequent potential for ground-
water contamination, solidi-
fication/stabilization (s/s) pro-
cesses are widely used to treat
wastes prior to disposal.  Typ-
ically, aqueous wastes containing
heavy metals are treated in this
manner.
    In brief, s/s processes involve
the use of additives to convert a
liquid waste into a solid mon-
olithic-matrix.  The contaminants,
which are then  contained within
such a matrix, will therefore
become less accessible to potential
leaching agents.  In some cases,
the additives are selected to also
react with and reduce the sol-
ubility of the contaminants.
                                    364

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Hence, an additional measure is
provided to further reduce the
potential for groundwater con-
tamination.

    Clearly it is important that
the physical integrity of such
treated wastes be maintained.
Disintegration, resulting in
generation of small particulates,
or formation of cracks, thereby
increasing the apparent per-
meability of the solid matrix,
would defeat the purpose for which
s/s processes are used.

    Such deterioration in physical
integrity could be caused by
adverse climatic conditions, such
as changes in temperature which
cause repeated freeze-thaw cycles.
Even if the treated wastes are
eventually buried under soil
layers, which would minimize such
effects, there is still an in-
termediate period during which
these wastes are exposed to such
adverse conditions.  Therefore, at
locations where freezing and
thawing occur, measurements of
ability to withstand these
conditions are an important and
integral part of s/s process
evaluation.

    This paper describes the
development of a new method for
quantifying the freeze-thaw re-
sistance of solidified wastes on
the basis of weight loss
measurements.
EXISTING METHODS

    To our knowledge, there are
only two existing methods for
measuring freeze-thaw resistance.
Both are ASTH standard methods,
developed for concrete and
soil-cement mixtures.  These are
briefly described as follows:

ASTH C 666-80. "Resistance of
Concrete.to Rapid Freezing and
Thawing" '

    The test specimens  are prisms
of 10 x 10 x 38 cm nominal di-
mensions, which are immersed in
water at 4.4°C during the thawing
phase.  For the freezing phase, one
of two procedures could be
adopted.  In Procedure A, the test
specimens remain in the water used
in the thawing phase, and in Pro-
cedure B,  they are exposed to
air.  In both cases, the freezing
phase temperature is -18°C,

    Several constraints are imposed
on the duration of the transition
period, on the rate of temperature
change during this period, and on
the minimum duration of the thawing
phase relative to that of one
freeze-thaw cycle.  However, strict
requirements are not specified for
the freezing and thawing periods.
Test specimens could be stored in a
frozen condition "indefinitely"
when interruptions occur.

    The freeze-thaw resistance is
expressed as durability factor
(OF), ranging from 0 to 100, which
is computed from measurements of
dynamic modulus of elasticity.
These measurements are carried out
at least once every 36 freeze-thaw
cycles.

    The prescribed number of
freeze-thaw cycles is 300, or that
when the dynamic modulus elasticity
reduces to 6035 of the initial
value.  The acceptable, within-
laboratory precision values are
specified in terms of standard
deviation and actual difference in
                                    365

-------
Individual OF values.  These vary
depending on the average DF: in the
range of 1-15 in standard deviation
and 2-43 in difference between test
results.

    This method was applied to
samples of Uranium mine-mill
tailings treated by a number of s/s
processes.2  Experimental dif-
ficulties were encountered, such as
surface scaling, sample dis-
integration and warping, and dif-
ficulties in carrying out
quantitative measurements were
reported.  From visual obser-
vations, however, the different
processes were ranked in terms of
freeze-thaw resistance.

ASTH D560-57 (Re-approved 1976).
"Freezingand ThawingTests of
Compacted Soi1-Cement Mixtures" 3

    The test specimens are cylind-
rical, with nominal dimensions of
10 cm diameter and 12 cm long.
Both the freezing and thawing are
carried out in air, with 100% re-
lative humidity and at temperatures
of -23°C and 21°C, respectively.
The freezing and thawing periods
are specified at 24 h and 23 h,
respectively.  As in the previous
method, during interruptions, test
specimens are stored in a frozen
condition.

    The freeze-thaw resistance is
expressed in terms of weight loss.
Measurements of weight loss involve
the application of "firm strokes"
on all surface areas of the test
specimen with a wire scratch
brush.  A firm stroke is defined to
correspond to approximately 13.3 N
(3 Ibf) as measured with a
balance.  For specimens that form
scales, a sharp-pointed instrument
such as an ice pick is to be used
instead of a brush.  These weight
loss measurements are usually made
after each freeze-thaw cycle.

    The prescribed number of
freeze-thaw cycles is 12.  No
specification is given on the
acceptable precision value for the
weight loss measurement.

    This method was applied to four
treated wastes with different types
of physical characteristics:  low-
strength concrete, rubber-like
solid, plastic-encased block and
soil-like material.4  With the
exception of one plastic-encased
sample, all samples disintegrated
after 12 freeze-thaw cycles.  In
fact, 62% of the samples disinte-
grated after 2 cycles.  The weight
loss measurement results were not
reported.

DESCRIPTION OF PROPOSED METHOD

    Various features of the
existing ASTM methods have been
adopted.  These include:

    (1)  Test specimens  are frozen
in air and thawed in water
(C666-80, Procedure B).

    (2)  The freezing and thawing
periods are 24 ± Ih, and the
maximum number of freeze-thaw
cycles is 12.  The freezing and
thawing temperatures are -20 +3°C
and 20 i 3°C respectively (0560-57).

    (3)  Weight loss is used as a
measure of freeze-thaw resistance
and measured after each cycle
(D560-57).

    Modification to the existing
methods have also been made, as
described below:
                                    366

-------
    (1)  The test specimens are 5
cm cubes.  This decrease in volume
is desirable to reduce both mat-
erial and space requirements for
sample preparation and for carrying
out the tests, respectively.  More-
over, it was originally planned to
use unconfined compression strength
(UCS) as a measure of freeze-thaw
resistance.  The standard method
for UCS measurements prescribes
test specimens of such shape and
dimensions.5

    (2)  Measurements of weight
loss are carried out on the removed
and dried particulate matters, and
not on the test specimens.  The
weight loss is then expressed on a
dry basis relative to the original
test specimen weight.  This
approach improves the precision of
the weight loss measurements, and
more importantly, eliminates the
necessity of accounting for moist-
ure changes in the test specimens
during the freeze-thaw cycles.

    (3)  "Control" specimens are
used to correct the weight loss
measurements.  These undergo iden-
tical treatment as the test speci-
mens except exposure to a low tem-
perature during the freezing
phase.  This approach has been
adopted to isolate the effect of
freezing and thawing from others
that might contribute to weight
loss, such as matrix dissolution.

    (4)  The removal of loose part-
iculates is carried out by
ultrasonic application followed by
rinsing, and not by a wire scratch
brush.  This approach has been
adopted to improve reproducibility
and to enhance differences in
weight loss, either between control
and test specimens or between
different test specimens.
    A brief description of the
procedure is as follows:
- Prepare and weigh test and
control specimens (see next
section).
- Prepare identical specimen for
measurement of moisture content and
computation of oven dry weight.
- Each specimen is placed in a
covered beaker with known tare
weight.
- Beakers containing test speci-
mens are placed in a freezing
cabinet, while control specimens
are stored in a moist container at
room temperature.
- At the end of the freezing phase
all of the beakers are filled up
with  distilled water to cover the
specimens and thawed in water.
- At the end of the thawing phase,
the specimens are exposed to
ultrasonic for 4 minutes, rinsed
with distilled water to the beakers
of origin and transferred to a new
set of beakers.  The water
containing the removed particulates
is evaporated and the dry solids
are measured.
- The cycling is repeated 12 times
unless specimens lose integrity
earlier in the process.

MATERIALS

    An aqueous solution containing
0.1 molar of As, Cd, Cr and Pb was
used as the waste.  Table I is a
summary of the types and quantities
of the additives used to treat the
waste.  These have been selected to
represent inexpensive s/s processes
that are at present widely
used,6.7 though the composition
of the matrix may not reflect the
best available s/s technology.  For
each set of treated waste specimens
a corresponding "blank™ set
(containing no heavy metal) was
                                     367

-------
 also  prepared  and tested.               Table I Summary of Additives Used

    Preparation  of test specimens,      Deslg,  Additives(b)   Ratio*3)
 Including mixing and molding, was	
 carried  out  using equipment as
 specified in the ASTH C305-828          A      Cement, Fly ash   1:0.45:2,1
 and C192-81.9  Modifications to         B      Lime, Fly ash     1:0.55:1.85
 the prescribed procedures were          C      Cement, Soluble   1:0.65:0.60
 however  made,  such as lengthening              Silicate
 the mixing time  to ensure homo-         D      Cement, Bentonite 1:0.55:0.85
 genelty.  All the test specimens        E      Gypsum            1:1
 were  cured for 28 days at room
temperature and in excess of 96%        (a) Weight ratio, waste:additive:
relative humidity.                      additive, in the order as shown in
                                        the second column.
               Table II Replicate Weigh Loss measurement results,
                   showing reproducibility of proposed method

                Cumulative relative weight loss after Indicated freeze-thaw
                cycle number (% dry basis)(a)


                1    2    3    4    5    6    7    8    9    10   11    12  Av.


                                TEST SPECIMENS**3)

Hean*c)        0.59 1.18 2.07 2.73 3.74 4.42 5.29 6.39 7.19 7.98 9.00 10.39

RSDX           0.74 7.23 13.1 7.37 4.70 8.04 12.2 16.3 13.8 11.5 12.2  7.65  9.5


                              CONTROL SPECIMENS*0)

Mean*c>        0.57 1.11 1.66 1.18 2.71 3.22 3.71 4.25 4.78 5.30 5.82 6.34

RSDX           1.24 1.42 1.84 1.09 0.61 0.85 0.40 0.39 0.17 0.13 0.07 0.20  0.7


(a)  Relative to specimen initial weight.
(b)  Gypsum process, see Table I;
(c)  Arithmetic mean of 4 measurements, specimens prepared from two batches;
     RSD-ratio of standard deviation to mean in %,
                                    368

-------
(b) Sources of materials

Cement (Portland Cement Type II) -
Genstar, Edmonton, Alberta
Flyash - Power Plant, Ontario
Soluble silicate (Type N) -
National Silicate, Toronto, Ontario
Bentonite (Voloclay No. 200) -
Western Bentonite, Edmonton, Alberta
Gypsum (Envirostone A, B and C) -
US Gypsum  Co., Libertyvilie, 111.

RESULTS AND DISCUSSION

Reproducibility

    An indication of the reprod-
ucibility of the proposed method is
shown in Table II, summarizing the
weight loss measurement results for
both the test and control specimens.

    In terms of weight loss
measurement, a relative standard
deviation of better than 2% could
be achieved, as shown by the
results for the control specimens.
Freezing and thawing, combined with
batch-to-batch variation, in-
troduced more scatter, which is not
unexpected.  A maximum  relative
standard deviation of 17.OS could
be achieved for cumulative weight
loss measurements after freeze-thaw
cycles.
    The results summarized in Table
II also show the importance of
using control specimens, especially
when matrix dissolution is con-
siderable.  By this means, the
contribution to the total weight
loss which is attributed to
freezing and thawing could be
isolated.

Applicability to Different S/S
Processes

    Figure 1 shows a comparison
amongst the five different
additives listed in Table I.  The
vertical axis represents cumulative
weight loss, relative to the
initial weight, expressed on a dry
basis and corrected for control
specimen weight loss.  The hori-
zontal axis shows the number of
freeze-thaw cycles.

    The results show marked dif-
ferences in freeze-thaw resistance
amongst the systems tested, ranging
in cumulative weight loss from 0.1%
after 12 freeze-thaw cycles to
about 3% after 5 cycles.  It is our
contention therefore, that the
proposed method provides a sen-
sitive means of comparing different
s/s processes on the basis of
freeze-thaw resistance.

    It is also interesting to note
the progression of the weight
loss.  For example, specimen  E
(Envirostone A) showed very little
weight loss up to 8 freeze-thaw
cycles, but then there was a
dramatic increase in weight loss,
followed by formation of cracks.
Figure 2 shows an example of a test
specimen  with cracks.

    It should be emphasized that
the proposed test method was not
developed for extrapolation
purposes, to predict freeze-thaw
resistance under actual field
conditions.  No consideration has
been given to the various
similarity factors that must be
accounted for in  order to develop
predictive capabilities.  Never-
theless, the proposed method could
provide a rapid indication of the
relative freeze-thaw resistance of
different s/s processes.
                                    369

-------
    34-^
         in
         o
                                              cement  & sol.  silicate
         .c
         en
         •r—
         0)



         0)
         3
         E
         3
         O
CO
*«J
o
cement &
Bentonite

                       gypsum "A1
    fig.  1
                                                                                                 .' lime flyash
    0 --

                                                                      y
                                                                      /
                                                                                                 — cement  & flyash
                                                                                        cycles
                                                                                   10
                             11
12

-------
FIGURE 2
Effect of Contaminants

    Figure 3 (Matrix C) and 4
(Matrix B)show the differences in
weight loss between test and blank
specimens that were exposed to
freeze-thaw cycles and also those
used as control specimens.  Also
shown in Figure 3 are the number of
freeze-thaw cycles at which speci-
men disintegration occurred.

    Somewhat curiously, some of the
test specimens which contained
contaminants displayed a higher
freeze-thaw resistance than the
blank specimens in which no con-
taminant was present.  It could be
speculated that contaminant-
-additive interactions or reactions
occurred, which resulted in im-
provements in freeze-thaw
resistance.  Investigation of the
possible mechanisms is, however,
beyond the scope of this paper.

Modifications and Extension of
Proposed Method

Ultrasonic Application

    A series of tests were carried
out to assess whether ultrasonic
application was necessary.  Elim-
ination of this means of removing
loose particulate matters would
simplify the method, and moreover,
concerns over standardization of
the ultrasonic equipment and its
method of operation would be
eliminated.  The results for both
test and control specimens are
summarized in Table III.

    Standard conditions were used
by centering samples immersed in
                                     371

-------
        o
        S-
        o
        o
        O)
                                                                                =»=
                                                                                tfi

                                                                                
-------
          OJ

          Q.

          at
                                                                                oo
 % sso[ 5.1)6 IBM
4	1	i	1
                                   373
                                                                             O     M~

-------
230ml water containing beakers
(type Klimax No. 1400) in an
ultrasonic bath (type Bransonic
221).

    For the control specimens a
marginal increase in weight loss
was indicated as a result of ultra-
sonic application.  However, for
the test specimens  no apparent
change was observed.  In fact, in
terms of corrected weight loss
(ie. test-control), the effect of
                            ultrasonic  application  masked  that
                            of freezing and  thawing.   It would
                            seem that when freezing and thawing
                            alone were  sufficient to  effect
                            particulate removal,  ultrasonic
                            application produced  little
                            additional  effect.

                                For the above reason  and also
                            for simplicity,  ultrasonic
                            application is judged unnecessary
                            and hence will be abandoned in
                            future tests.
Duration
(Minutes)
Table III   Effect of Duration of Ultrasonic Application


                                           Control	
           Weight Loss, %  (a)
  Test Specimen (b)   	
Mean(c)
                                            Range
                                             Meantc)
SP(c)
0
4
8
0.55-0.80
0.55-0.80
0.60-0.80
0.68
0.70
0.70
0.08
0.08
0.08
0.45-0.85
0.60-0.80
0.65-0.80
0.61
0.66
0.70
0.12
0.07
0.05
(a)  Relative to initial weight, dry basis
(b)  Gypsum system E, see Table I
(c)  Computed arithmetic mean and standard deviation (SD) of weight loss
     measurements over 12 freeze-thaw cycle.
Test Specimen Dimensions

    As previously mentioned, 5 cm
cubes were used since it was
originally planned to incorporate UCS
measurements to characterize freeze-
-thaw resistance.  UCS measurements
are destructive, hence a large number
of specimens need to be prepared.
Because of this disadvantage, and
furthermore, because weight loss
measurements are sufficient to
characterize freeze-thaw
resistance, in future tests cylin-
drical specimens, 4.4 cm  diameter and
7.4 cm long, will be used.  These
specimens can be prepared using
readily available plastic vials.  A
                            further advantage is thus  gained  in
                            that these vials are considerably less
                            costly than the metalic molds  required
                            to prepare cubical  specimens.

                            Future Plans

                                A cooperative project, involving
                            US EPA, Environment Canada,  the
                            Alberta Environmental Centre and
                            vendors of s/s processes,  will  be
                            undertaken to assess the applicability
                            of various short-term laboratory  test
                            methods.10  The proposed test  method
                            is included in this project.  Thus,
                            further information will be  gathered
                            on its applicability to a  wide variety
                            of wastes, including "real wastes",
                            treated by commercially used s/s
                                     374

-------
processes.  Information on inter-
-laboratory reproducibllity will also
be pursued by conducting a round-robin
study under of ASTM D-34.  Development
of the method to an ASTM standard
level will then be considered.

    Also included in the co-operative
project is a test method for measuring
wet-dry resistance.  The approach used
in the proposed method for measuring
freeze-thaw resistance will be
adopted:  the use of weight loss as a
measure of wet-dry resistance, control
specimens to correct test specimen
weight loss measurements, and the same
particulate removal method.  The
wetting and drying phases will be
carried out at 20 ± 3°C, 60±3°C for 24
hrs and 23 hrs, respectively.  The
weight loss measurements  will be
carried out after each complete
dry-wet cycle.
CONCLUSIONS

    The development of a method for
measuring the freeze-thaw resistance
of solidified/stabilization wastes has
been described.  Novel features are
introduced, including methods for
particulate removal and weight loss
measurement, and the use of control
specimens to isolate the effect of
freezing and thawing.

    The initial results obtained show
promise in terms of reproducibility
and ability to detect differences
amongst different s/s processes.
Various modifications have been
introduced to simplify the method, and
further tests are planned to assess
the applicability of the method to a
wide variety of soldified/stabilized
wastes and to obtain inter-laboratroy
reproducibility values.

    Adoption of the proposed method
for measuring wet-dry resistance will
also be assessed.
ACKNOWLEDGMENTS

    The authors  greatfully acknow-
ledge the scientific support of
Environment Canada Wastewater
Technology Centre, and personally Mr.
Pierre Cote.

    Obtaining data on gypsum became
possible by the assistance of
Mr. Ken Watkins and the US Gypsum Co.

REFERENCES

1.  ASTM  C 666-80.  American Society
    for Testing and Materials, Annual
    Book of ASTM standards, Part 14,
    1980.

2.  Bruce R. B., at al.  Physical and
    Chemical Properties of Chemically
    Fixed uranium Mine-Mill Tailings,
    Ontario Research Foundation Final
    Report, May, 1981.

3.  ASTM  D 560-57.  American Society
    or Testing and Materials Annual
    Book of ASTM Standards, Part 19,
    1980.

4.  Physical and Engineering
    Properties of Hazardous Industrial
    Wastes and Sludges,
    EPA-600/2-77-139, August, 1977.
    US EPA Cincinnati, Ohio  45268.

5.  ASTM  C 109—80  American Society
    for Testing and Materials, Annual
    Book of ASTM Standards, Part 14,
    1980.

6.  Cote, Pierre and Donald Hamilton.
    Leachability Comparison of Four
    Hazardous Waste Solidification
    Processes, presented at 38th
    Industrial Waste Conference
    May 10-12, 1982.
                                    375

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EPA 600/2-79-056, July, 1979.       9.  ASTM  C 192-81.   American Society
Survey of Soldification/-               for Testing and  Materials, Annual
Stabilization Technology for            Book of ASTM Standards, 1981.
Hazardous Industrial Wastes, by US
Army Engineer Wasteways Experiment  10. "Proceedings of  The Environmental
Station, Vicksburg, MS  39180.          Assessment of Waste Stabilization-
                                        /Solidification  Workshop."  Nov.
ASTM  C 305-82.  American Society       21-22, 1983, Alberta Environmental
for Testing and Materials, Annual       Centre, Vegreville, Alberta (in
Book of ASTM Standards, 1982.           press).
                             Disclaimer

               The work described in this paper was
               not funded by the U.S. Environmental
               Protection Agency.  The contents do
               not necessarily reflect the views of
               the Agency and no official endorse-
               ment should be inferred.
                                376

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                              PARTITIONING ANALYSIS
                              OF CHEMICAL SUBSTANCES
                   AS A TOOL FOR MANAGING HAZARDOUS WASTE STUDIES

                        Surya S. Prasad and James S, Whang
                                    AEPCO, Inc.
                                Bethesda, MO 20816
                                     ABSTRACT
     Partitioning  analysis  schemes  were applied to determine distribution of repre-
sentative chemical pollutants within water  to  air and soil  to air pathways.  Esta-
blished theoretical and/or empirical mathematical representations and models;  and
available  chemical  property data were used.   Information  elements  for the schemes
included the  physical, chemical, biological,  and environmental  characteristics of the
chemicals and  the  partition  coefficients.   Relative  fitting of the parameters into
the existing mathematical representations or models was assessed.  Certain data
inadequacies  were taken into  account.

     The findings  suggest that within hazardous waste  management  studies, partition-
ing analysis  is useful  in:

     o Identifying the  predominant  environmental  compartment(s) where a given chemi-
       cal  will reside.
     o Assisting in the design of optimal  field sampling programs.
     o Estimating half-life and  mobility, degree of bioaccurnulation,  residence time
       for  degradation  and  transformation, time of risk exposure,  and  toxic  effects.
     o Establishing bases for the selection of remedial measures.
     o Developing  representative conditions for laboratory or pilot-scale treatabili-
       ty studies.
     o Providing guidance for designing  study protocols.
     o Assisting engineers  in designing remedial disposal  methods  minimizing adverse
       environmental  impacts.
     o Providing guidance in the formulation of environmental regulations.
INTRODUCTION AND PURPOSE

  After a pollutant is released  into the
environment, it is distributed  chiefly
among  three compartments:   air (atmos-
pheric),  water (aquatic), and  soil  (ter-
restrial).   The concentration of a che-
mical present initially  in each compart-
ment is  a function of both  its  proper-
ties and type of release. Once  present
in the environment, the chemical under-
goes dynamic changes which are a fun-
ction  of intercompartmental  transfers,
transformations, and degradations.  Lf
the pollutant is persistent, the poten-
tial  for eventual  uptake by aquatic and
terrestrial  organisms  increases.  Conse-
quently through  biomagnification,  it is
                                       377

-------
possible for concentrations  in  biologi-
cal tissues to reach a  level, which may
cause  significant toxicological  hazard
to humans and other populations.

  Health and  environmental  hazard or
risk assessments can be initiated once
the pollutant-favored environmental com-
partment is  delineated.   One of the most
difficult tasks in performing  these risk
assessments is adequate screening and
testing of  large numbers  of  chemicals
under stringent time  and budgetary con-
straints.   To alleviate this problem,
partitioning  analysis  can   assist  in
focusing limited  resources to key media
and elements of the risk assessments.

  Water-to-alr  and  soil-to-water  parti-
tioning schemes involve the use of ma-
thematical  representations  or  models
that are predominantly based on chemical
partitioning  properties  such as  the
molecular  formula, structure,  and
weight; specific gravity and density;
vapor pressure and density;  solubility
in water and certain organic solvents;
octanol/water partition  coefficient;
soil adsorption  coefficient;  half-lives
related to  evaporation,  photolysis,
hydrolysis, and other physical, chemi-
cal, and biochemical  reactions.  Predic-
tive mathematical models based  on the
above properties  can  either be  obtained
from  the  available literature  or be
specifically developed.

APPROACH

The following general categories  of the
potential  transformation and transport
pathways were studied.
  o Intercompartmental transfers
  o Transformation,  bioaccumulation,
    biomagnification
  o Environmental  degradations
        Each environmental  pathway  was  consi-
       dered separately as a function  of  the
       physical  and chemical properties of  a
       given  chemical pollutant in relation to
       the  intercompartmental  transfer (the
       transport and redistribution processes
       among the environmental solid,  liquid
       and  gaseous  phases.)

       Hater-to-AIr Models

        The  two models employed  in this phase
       of the study were originally proposed by
       Uilling (Model I,  1977)  and Mackay  and
       Leinonen  (Model  II, 1975).
       Model  I
         H =
        Kl «
               16.U4 x P x M
                   T x S
                    221.1
              (1.042/H + 100) X M0*5

       t1/2 =  (0.6931) x d / K,

       where,
         H   =  Henry's law  constant (dimension-
              less)
         P   =  Vapor pressure (mm Hg)
         M   =  Molecular weight (gm/mole)
         T   =  Absolute temperature  (°K)
         S   =  Solubility in water (mg/L)
         Ki  =  Overall  liquid exchange constant
              (cm/min)
       ti/2 =  Evaporation half-life (min)
         d   =  Solution depth  (cm)
and
       Model II
          H =
                VP
                ws
                                      378

-------
n/2 '

where3
  H  •

  VP =
  WS *
 kiLs
 kiG
 MW  -
1/2  *

 R   -

 T   .
        U.2 x (MU of C02)
                         0.5
        (MW of Compound)0*5
        30 x (MW of H2U)

        (MW of Compound)
                        0.5
                        0.5
K1L
              H  x
             x L
                      /(R x T)
Henry's  law constant (atm-m^/
mole)
Vapor pressure  (atm)
Water solubility (moles/gm)
Liquid film  mass transfer coeffi-
cient (m/hr)
Gas  film  mass transfer  coeffi-
cient (m/hr)
Overall  liquid  coefficient (m/hr)
Molecular weight (gm/rnole)
Volatilization  half-life  (hr)
Liquid depth  (assumed 1 m)
Gas constant  =  8.2 x 10"6 (m3-
atm/tnole-°K)
Absolute temperature  (°K)
  Water-to-air partitioning was repre-
sented by the  half-life of a chemical  in
a water  body  of given depth.   It was
assumed that the water depth was 1  m and
the water temperature was at 20°C.   The
partitioning procedures were:

  1. Obtain vapor  pressure  and water
     solubility data from reliable  sour-
     ces.
  2
  3.
     Calculate  Henry's law constant.
     Apply these values to the Oil I ing
     or Mackay  and  Leinonen models to
     calculate  coefficients/constants
     and the ha If- life.
                                           Soil-to-Water Models

                                             The two models adopted for this phase
                                           of the study  were originally proposed by
                                           Kenaga  and  Goring (Model  I,  1980)  and
                                           Briggs (Model II,  1973).
                                           Model I
                                            Log K
                                                 oc
                                             where,
                                                Koc
                                                 WS «
                                                     3.64  -  0.55 x (Log WS) ± 1.23
                                                     order of magnitude
                                                     [95% confidence level and
                                                     correlation coefficient of
                                                     0.84]

                                                     Soil/water partition coeffi-
                                                     cient per unit  organic  matter
                                                     (dimensionless)
                                                     Water solubility in (mg/L)
                                           Model II
                                              Log Q = (0.524 x  Loy  P) + 0.618
                                              where,
                                                  Q
                                                  P =
                                                      Soil organic  matter/water
                                                      partition coefficient (dimen-
                                                      sionless)
                                                      Octanol-water partition coef-
                                                      ficient (dimensionless)
                                    For the definition of soil adsorption
                                    capabilities, we adopted KQC (Kenaga  and
                                    Goring,  1980) and Q  values  (Briggs,
                                    1973).   We assumed that the soil/water
                                    matrix  was at an equilibrium temperature
                                    of 20°C.   The procedures used for  calcu-
                                    lating  KQC and Q were:

                                      1.  Obtain water solubility data from
                                         rel1able  sources.
                                      2.  Calculate the relevant  transfer
                                         coefficient(s) in  the Kenaga  and
                                         Goring's and Briggs1 models.
                                      3.  Calculate KQC  and Q values.

                                       Mobility of a given  compound  from  soil
                                     to water  (e.g., by leaching) is a  fun-
                                       379

-------
ction of soil  adsorption coefficents.
The mobility  rating scheme proposed by
Kenaga (1980) is as follows:

  o Immobile (KQC  >  1,000)
  o Moderately  to highly mobile
    (Koc <  1UU)

  The mobility  rating scheme proposed by
Brlggs is as follows:

  o Immobile (Q >  398)
  o Low (398 >  Q >74)
  o Intermediate (74 > q > 29)
  o Mobile (29 > Q > 4.5)
  o Very mobile (Q < 4.b)

PROBLEMS ENCOUNTERED

  The  applicability  of  the proposed
partitioning  schemes  was  generally
limited by the  following;

  o They are less effective for chemical
    pollutants  having  inadequate  or in-
    complete data.
  o The  analysis was  based on  purely
    empirical  data and detailed experi-
    mental  protocols  were  not esta-
    blished.
  o The schemes were generally  appli-
    cable to known  and pure compounds
    only.
  o The schemes served  as  a  guide to the
    partitioning character  of the indi-
    vidual  compounds studied  individual-
    ly but  yielded no information on the
    environmental  partitioning of heter-
    ogeneous groups of toxic  chemicals.

  Furthermore, information was  inade-
quate on the environmental transforma-
tion or transport  pathways  of pollutants
for which  mathematical models are not
readily available.   Some of the availa-
ble models are formulated  in  terms of
kinetic parameters rather than  simple
physical and chemical  data.   Application
 of these  models  is  limited  because they
 lack published  kinetic data for  most
 compounds.   Availability  of  relevant
 field data  are  scarce  for environmental
 partitioning  scheme  development  and
 validation.
RESULTS

Hater-to-Air Partitioning

  The results  of  calculations for the
selected  compounds are  summarized in
Table 1.   The calculated half-life
values range from 4.8 to 14.U hours for
all compounds,  except  for aniline, iso-
phorone, and phenol having a predicted
half-life  greater  than  382.2  hours.
Figures  1,  2,   and  3  are plots of the
results.   The following  conclusions can
be generalized from Table 1 and these
plots:

1. Effects of  vapor pressure  on water
   solubility and  half-life (Figure  1):

   o Water  solubility increases  with
     increasing  vapor pressure
   o Half-life  decreases  with increasing
     vapor  pressure

2. Effects  of water  solubility on half-
   life  (Figure  2):

   o Half-life decreases  with increasing
     water  solubility

3. Effects  of molecular weight on vapor
   pressure, water solubility, and half-
   life  (Figure  3):

   o Vapor  pressure and water solubility
     decrease with increasing molecular
     weight
   o Half-life increases  with increasing
     molecular weight
                                       380

-------
              Table 1.   Summary of  Water-to-Air  Partitioning  Analysis
MOOCL i
(OMIIng, 1977)
IIPUT PARAMETERS*
VAPOR PRESSURE
COfCUND
BEKENE
TOLUENE
CHLOROFOW
NOWCHLOR08ENZENE
TRICHLOROETHYLENE
t,5-OICHl«OBENZENe
TETHACHI.OROETHYLENE
1 ,2-DHXLOROeEKZEKE
l,4~0!CHLO«Qe£NZE«E
I,2,4-TRIO4LOR08£NZENE
1 , 2,4 , S-TETRACHLOROBt«ENE
MEXAOILOHOCrCLOPEHTAO 1 EHE
•NILINE
ISQPHORONE
PMEWL
'Nacuy ana L»Jnon»n (1975
{mm Ho)
95. ZO*
28.40°
200.00*"
8.80C
74.00°
l.89d
15.80"
1.00=
0.60C
0.2911
0.05d
0.08'
i.oo"
0.20^
1 .00^
Jj filling.
(»"•>
1.25E-Q1
3. 74E-02
2.63E-01
1.16E-02
9.74E-02
2.4M-03
2.08E-02
1.S2E-03
7.89E-04
3.82E-04
6.56E-OS
I.05E-04
1.32E-03
2.63E-04
I.52E-05
MOLECULAR
•EIGHT
10«/rol.l
78.11
92.15
119.39
112.56
131.39
147.01
165.82
147.01
147.01
181.45
215.90
272.77
93. 1J
138.21
94.11
_ _n_
•t «l. (HJ5H ev»r»eli
WATER SOLUBILITY
(1I9/L1
1.78«>03*
5.15E*02°
7.9SE*03b
5.00f«02!:
I.IOEKIS"
1 .23£*02e
4.00E»02'>
1 ,OOE*02e
7.90£»0l'!
3.00E*OI*
6.00E-KJO*
1.80E«CO°
3.6M»04*
f .20E-*O4
8.20E»(X*
u»r«n I197I); '
l.ol. /mJ)
22.79
5.39
66.S9
4.44
8.37
0.84
2.41
0.68
0.54
0.17
0.05
0.01
293.00
86.82
•71.J2
3R.«.r«=,
HEWW'S
CONSTANT
Kit)
2.29E-01
2.78E-01
I.64E-01
1. 081-01
4.84E-01
1.24E-OI
3.58E-01
8.05E-02
6.IIE-02
9.60E-02
9.84E-02
6.64E-01
1.39E-04
I.26E-04
«.2»6-05
1 tt«B8); *K»
LIQUID
EXCHANGE
CONSTANT MALF-
«, LIFE
met. 11
(MacKav *nd L*lnon*n
HE MIT'S
CONSTANT
(c*/nln) (hr) /f«ol>
0.239
0.222
0.190
0.190
0.189
0.1(8
0.167
0.161
0.156
0.141
0.156
0.132
0.003
0.002
0.001
naga and
4.8
'.2
6.1
6.1
6.!
6.9
6.9
'.2
7.4
'.8
8. 5
8.8
382.2
513.7
B4S.7
5.50E-05
6.68E-03
3.9SE-03
2.61E-03
l.l'E-02
2 97E-03
8.62E-03
1 .9JE-03
I.47E-OS
2.31E-05
2.J7E-03
I.60E-02
3.35f-0«
3.05E-06
1.51E-06
Borlnj CI980); 'll-tin
OKEHALL
TRANSFER
OOEFF.
(B/BD
0,144
0.133
0.114
0.114
0.113
O.I 01
0.100
0.0»7
0.093
0.089
0.082
O.OJ9
0.002
0.001
0.00 1
S196J>! 'o
. 19751

H»LF-
LIFE
inn
4.8
5.2
6.1
6.1
£.1
6.9
6.9
7.2
7.4
7.8
8.3
8.8
382.3
313,8
845.9
,,„„,„
(1979); "Sax (1979);  Ha»l»y (19771;
                             (1980); and frowning (1965).
   2-
   1-
   -1.5      -0.5  0   0.5       1.5
           Log (Vapor Pressure, ran Hg)
                                      2.5
      D MS  « Hater Solubility (rag/L)
      f ti,  " Half-Life {hr)
      ^ KQC (Dimensionless)

Figure 1.   Effects of Vapor Pressure
             (VP)  on Water Solubility,
             Half-Life, and
                                                         8-
                                                         7-
                                                         6-
                                                         5-
                                                         4-
                                                         3-
                                                         2-
                                                          0123
                                                                Log (Water Solubility, mg/L)

                                                           D tij  » Half-Life (hr)
                                                           "*" 'Sec (Dimension!ess)
                                                      Figure  2.  Effects  of Water Solubility
                                                                  on Half-Life  and
                                               381

-------
    9-

    8-

    7-
 o.

 ?  ^
 «J
 u  c,
 o  3

 sg  4'

 -•  3


 3  2-
 «JI  1,


 £.  0-

    -!•
    -2.
     70   100     150     200     250
            Molecular Height (gin/mole)
       0 t, • Half-Life (hr)
       + K3C (Olmensfonless)
       $ HS « Hater Solubility (ng/L)
       A VP • Vapor Pressure  {ran Hg)
                                280
Figure 3.  Effects of Molecular Weight
          on Half-Life (tj,),  Kg,.,
          Water Solubility and va
          Pressure
                               apor
  These findings  are most pronounced for
the chlorinated  benzenes, probably due
to their similarity in molecular struc-
ture.   Extrapolating  this  finding,  par-
titioning  analysis  may  be useful  in
predicting  the volatilization potential
of exotic compounds of unknown physical
properties by  drawing  analogies  from
closely  similar compounds within the
same family.   An increase  in chlorine
atoms per molecule causes an increase in
molecular  weight, a decrease  in vapor
pressure, a decrease in water solublity,
and  an  increase  in  half-life.   Com-
pounds of  higher molecular weight and
longer  half-life  tend to favor the aqua-
tic over the atmospheric compartment.
Other  observations, awaiting further
confirmation,  are that the structural
positions of chlorine  atoms  on  the  ben-
zene rings  somehow dictate the values of
 vapor pressure and water solubility, and
 hence  the  half -life  of the compound
 within the chlorinated benzene family.

  Aniline,  isophorone, and  phenol  nave
 vapor pressure values  very close to that
 of most compounds listed in  Table 1, but
 they also have  nigh water solubilities.
 The  latter  property  hinders the  vola-
 tilization process.

  Focusing on  the volatilization poten-
 tial or  half-life  of various  benzene
 derivatives, some  guidance information
 relevant to  hazardous  waste  management
 can be preliminarily deduced.  For exam-
 ple, high volatile  substances, which
 upon their  release  to the environment
 favor air pathways,  are more amenable to
 removal by air or steam stripping.  Fur-
 thermore, half- life data can be  used to
 estimate the emission  strength  of sour-
 ces and to assess their  risk potential
 within  hazadous waste sites or produc-
 tion facilities.

 So i 1 -to- Mate r Part i t i on i n g

  The results of the calculations of the
 soil adsorption capabilities  for  the
 compounds studied  are  summarized  in
 Table  2.    The calculated  KQC  values
 range from 9 to 3,lb9.  The calculated Q
 values  range from 5  to 1,162.  In gener-
 al, KQC and Q values and their  respec-
tive mobility  ratings agree with each
other very  well.  Figures 1, 2, and  3
contain plots  of results for all com-
pounds except for aniline, isophorone,
and phenol.  The following conclusions
can  be  generalized  from Table 2  and
these figures:
1.  KQC decreases with increasing  water
              and  vapor pressure (Fi-
     solubility
     gures 1 and
                                                              vapor  pressure
                                                          2, respectively)
                                       382

-------
                Table 2.   Summary of Soil-to-Air Partitioning Analysis
                          MODEL I (Kenaga and Goring, I960).
               HQOB. II, (Brlgas, 1973)


COMPOUND
PHENOL
ACRYLQNITRIIE
ANILINE
1 SOPHORONE
CHLOROFORM
BENZENE
raiCHLOROETHYLENE
TOLUENE
HONOCMLOROBENZENE
TETRACHLORQETHYLENE
,3-OICHLOR06ENZENE
,2-OICHLOROBENZENE
,4-OICHLCROBENZEN£
, 2 ,4 -TR 1 CHLOROBENZENE
,2,4, 5-TETRACHLOR08ENZENE
HEXACHLOROCYCLOPENTAD 1 ENE
WATER
SOLUBILITY
(mq/L!
8.20E«4a
7.50E»04°
3.66£+04a
1.20E+04C
7.95E+05d
I.7BE+038
I.IOE«3d
5. I5£*Q28
S.OOE+02f
• 4.00E+0211
I.23E-HJ2*
I.OOE+02f
7.90E+OI*
3.00E+OIa
6.00E+008
I.BOEtOO9
SOIL
ADSORPTION
COEFFICIENT
Koo
(dimension- RELATIVE
less)
9
9
U
25
31
71
93
141
143
162
309
347
395
672
1,629
3, (59
MOBILITY*
Highly mobile
Highly mobile
Highly mobile
Highly mobile
Highly mobi la
Moderately mobile
Moderately mob Me
Moderate! y mobi *e
Moderately mobl U-
HoderaTety mobile
Moderately nubl 1*
Moderately mobile
Moderately mobile
Imtobl le
Innmobi le
1 fflmob 1 1 e
OCTANOL-WATER SOIL
PARTITION ADSORPTION
COEFFICIENT COEFFICIENT
Log P 0

(dimension- (dimension- RELATIVE
less) less)
0.23*
0.26«
0.5I«
2,26"
1.90«
2,13"
l.72«
2.2t«
5
6
8
63
41
54
33
60
2. 13* 58
2.W" 51
3.44* 263
3.40* 251
3.39* 246
4.17* 635
4,67* 1,162
3.99* 511
MOBILITY*"
Mobile
Mobile
Mobile
n termed late
fitermedlate
ntermad 1 ate
n termed late
n termed late
ntarfflediate
n termed la to
LOM
Lo«
LOW
irmoblle
Imioobl le
Imobl le
      * Based on the mobility rating method proposed by Kanaga, 1980.
      •• Calculated using the equation suggested by Kanaga and Goring, 1980.
      * Values reported by Hanscn and Leo, 1979.
     *** Based on the rnobltlty rating method proposed by Briggs, 1973.
      °Kanaga and Goring (1980); bKenaga U9aO); qBro«tn§ (1965)i tfOI 11 Ing et al. (1975); 8Mackay and Lelnonen (1975);
      fverscnueren (1977);  and 9Callanan (1979).
  2. KQC increases with increasing mole-
     cular weight  (Figure  3)
  These general findings  are also most
consistent for  the family  of  chlorinated
benzenes, probably  due to their simi-
larity in molecular  structure.   Extrapo-
lating tnis finding, partitioning analy-
sis  may  be useful  in  predicting the
mobility  of exotic  compounds of  unknown
physical  properties  by drawing  analogies
from  closely similar compounds within
the same family.  An  increase  in chlo-
rine  atoms per molecule causes a de-
crease in water solubility (which corre-
lates well with an increase in  molecular
weight), an increase  in KQC  or Q, and a
decrease in mobility from  aquatic  to
terrestrial compartments.   Compounds  of
higher KOC or  Q tend to  resist leaching
and stay  in the terrestrial compartment.
Other tentative observations,  awaiting
further  confirmation,  are  that the
structural positions  of chlorine atoms
on the benzene rings somehow  dictate the
values of  water solubility,  and,  hence,
the mobility  of the compound within the
chlorinated benzene family.

  Regarding guidance information for the
management of hazardous waste,  prelimi-
nary  findings  suggest that  compounds
having high mobility tend to escape from
their sources of release by leaching and
to contaminate surface  water  and ground-
water systems.  These compounds  are more
effectively recovered  from water media
(e.g.,  via groundwater pumping  or lea-
chate  interception)  for central onsite
or offsite treamtent.
                                        383

-------
  Compounds  having low mobility tend to
remain at  the source,  potentially
causing bioaccumulation and biomagnifi-
cation problems.  However, these com-
pounds  can  be effectively removed by
exacavation  or controlled  by  source
containment  and  encapsulation.

ACKNOWLEDGEMENTS

  Information  in this paper was obtained
in part from a study project  sponsored
by the United  States Environmental Pro-
tection Agency.

REFERENCES

 1. Briggs,  G.6., 1973, A  simple rela-
    tionship  between soil adsorption
    coefficients.  Proceedings 7th Bri-
    tish insecticide  and Fungicide Con-
    ference, pp. 83-86.

 2. Browning  E.,  1966,  Toxicity  and
    metabolism  of  industrial solvents.
    New York,  NY:  Elsevier Publishing
    Co.

 3. Callahan,  M.A.,  H.W.  Slimak,  N.W.
    Gabel, et  al., 1979, Water-related
    environmental fate of 129 priority
    pollutants: II. Halogenated  alipha-
    tic  hydrocarbons,   halogenated
    ethers, monocyclic aromatics,  phtha-
    late  esters,  polycyclic aromatic
    hydrocarbons, nitrosamines,  miscel-
    laneous compounds.  Monitoring and
    Data  Support  Division,   Office of
    Water Planning  and Standards, U.S.
    EPA, Washington,  D.C.,  EPA-44U/4-79-
    029b.
 4, Oil ling,  W.L.,  N.8. Tefertiller and
    G.J. Dallos, 1975, Evaporation rates
    and  reactivities of  methylene chlo-
    ride, chloroform, 1,1,1-trichloro-
    ethane, trichloroethylene,  tetra-
    chloroethylene, and other chlori-
    nated compounds in dilute  aqueous
    solutions.   Environ.  Sci.  Technol.
    9:833-B3B.

 b.  Dill ing W.L.,  1977,  Interphase tran-
    sfer processes.   II.  Evaporation
    rates of  chloro methanes,  ethanes,
    ethylenes, propanes, and  propylenes
    from dilute aqueous solutions.  Com-
    parisons  with theoretical  predic-
    tions.  Environ.  Science &  Technol.
    11:4U5-4U9.

 6.  Hansch, C. and A, Leo,  1979,  Substi-
    tuent constants for  correlation
 .   analysis  in chemistry and  biology.
    New  York,  NY:   John Wiley and Sons.
 7.  Hawley, G.G,  (Editor), 1977, Conden-
    sed  chemical  dictionary, 9th ed. New
    York,  NY:   Van Nostrand Reinhold Co.

 8.  Irish, D.D.,  1963, Hydrogenated
    hydrocarbons: hexachlorocyclopenta-
    diene.   In:  Patty F.A.  (Editor),
    Industrial  hygiene and toxicology,
    2nd  rev. ed., New York: Johy Wiley &
    Sons, Inc.  pp. 1333-1363.

 9.  Kenaga E.E.,  1980,  Predicted biocon-
    centration factors  and soil  sorption
    coefficients  of pesticides and other
    chemicals.   Ecotox.  Environ. Safe-
    ty.  4:26-.38.

10.  Kenaga E.E. and C.A.I.  Goring, 1980,
    Relationship  between water  solubil-
    ity, soil sorption, octanol/water
    partitioning, and  bioconcentration
    of chemicals  in biota.   In:  Eaton
    JC,  Parrish  PR,  Hendricks AC, eds.
    American  Society  for Testing and
    Materials.  ASTM STP  7U7.   pp. 78-
    115.

11.  Mackey I), and P.J. Leinonen, 197b,
    Rate of evaporation of low-solubil-
    ity  contaminants  from water bodies
                                      384

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    to atmosphere. Environ.  Science &
    Technology 9(13): 1178-1180.

12.  Richardson,  L.T.,  1968,  Selective
    vapor phase activity  of chloronitro-
    and  chlorobenzene in  soil.  Phytopa-
    thology.   58:316-322.

13.  Sax, N.I., 1979, Dangerous  proper-
    ties of industrial  materials. 4th
    ed.  New  York, NY:   Van  Nostrand
    Reinhold  Co.

14.  U.S. Environmental  Protection Agen-
    cy,  1984,  Effluent Guidelines Divi-
    sion.  Combined Sewer Overflow Toxic
    Pollutant Study.    EPA  440/1  -
    84/304. April   19b4.   p.  38. yashing-
    ton, O.C.

15.  Vershueren,  K., 1977,  Handbook of
    environmental data on organic chemi-
    cals.   New York, NY:  Van Nostrand
    Reinhold  Co.
                                     Disclaimer

                       This paper has been reviewed in
                       accordance with the U.S. Environ-
                       mental Protection Agency peer and
                       administrative review policies and
                       approved for presentation and publi-
                       cation.
                                    385

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                      RECYCLING AND CLEANER TECHNOLOGY
                  AS A MEANS  OF HAZARDOUS WASTE MANAGEMENT

                             Dr. Klaus Muller
                National  Agency of Environmental Protection
                           Copenhagen, Denmark


                                 ABSTRACT

    Increasing amounts of wastes, new  hazards,  new types of wastes,  and
limited possibilities for disposal or  incineration  of hazardous wastes create
the need for new ways in hazardous waste management.

    Great progress  has  been made in the  development of new technologies  for
treating hazardous wastes, but the so-called "end-point-solutions" will not be
sufficient to solve the problem.

    Recycling and cleaner technologies are presented as new concepts and means
for hazardous waste management.

    Recovery methods  as a part of recycling activities  have great importance
and are demonstrated by some examples.

    Cleaner technologies  try  to avoid  hazardous waste problems by regarding
the whole  production and product-life  cycle.  Problems  and examples  of  the
diffusion of cleaner technoloiges are discussed.

    Denmark has established  a system for promoting recycling and  cleaner
technologies acitivites; some  experiences are presented.
                                    accept  new industrial installations  at
INTRODUCTION                         various  distances  from the  homes.
                                    Source:/U.S. Council.../)
    Hazardous  wastes  are the  new
challenge of our time—all over the      Figure 1 shows  the lowest percentage
world.    We  are   all  aware  of  of people willing to accept new disposal
increasing  amounts  of wastes;  sites for  hazardous  waste  chemicals  in
household  wastes,   post-consumer  their neighborhood—even  nuclear  power
wastes,   industrial   wastes,  plants  are  not as  threatening as  those
agricultural  wastes and—last,  but  disposal sites!   It is, furthermore,
not least—hazardous wastes.   This  becoming more and more difficult—at
is a threat to all  nations in that,  least in Europe — to  find suitable  and
not only are the amounts of  wastes  accepted disposal  sites for all kinds of
increasing,   but  also  the'wastes.    We  are  confronted  with
dangerousness  and  the   risk,  increasing  amounts  of hazardous  wastes
especially of  hazardous  wastes,  and we need new solutions for hazardous
People feel this and, as  an example  waste management!
of their opinion and their feelings,
I will  show a  result of  a national      in  the  future  we will have  to deal
opinion survey which demonstrates  with new production methods,  with  new
the need for active work to find new  products, and  with new environmental
ways  of  dealing  with  hazardous  problems:  this strengthens the need not
wastes.  (See  Figure  1:   Cumulative  only for new technologies, but even more
percentage of  people  willing   to  for  new  strategies  and concepts  for

                                  386

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treating  hazardous wastes—and
recycling and  cleaner  technologies
are the  approaches for solving these
problems in the future!

Figure 1.   Cumulative percentage  of
people   willing  to accept  new
industrial  installations  at  various
distances from their  homes.
         Hazardous Waste Treatment

         Hazardous waste is  a very  wide  and
         unprecise term—it covers generally a-11
         wastes which  are  regarded as  toxic,
         reactive,  corrosive  or  radioactive.
         Just the fact that you  can find two such
         divergent numbers as  150 million tons
         versus 67 million tons, as the amount of
          100
           10
         Wouldn't Less
          m»tt*r  Than
         on* way one
          or the  mile
          other
*-S »-9 1O- IS- 20- 30- 4O- SO 51-  100 1O1*  Don't
      14  19  29  39 49    39         want

        Miles                     .-•»«•»
                                 distant*
 U.S.   Council  on  Environmental
 Quality,  Department of  Agriculture,
 Department  of  Energy,    and
 Environmental  Protection  Agency:
 Public  Opinion   on  Environmental
 Issues:   Results  of  a  National
 Public  Opinion Survey,   Washington,
 Government Printing Office, 1980.
          hazardous waste production projected for
          the  United States  in  1985, shows the
          problem  of defining and of controlling
          hazardous wastes!

              I  do   not  want   to  add  a   new
          definition  to the existing ones; I just
          take hazardous wastes as a problem which
                                   387

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has to be solved!   In the past it
was easy to  dump those wastes, but
an Increasing  understanding of our
environment,  a rise  in  public
consciousness,  and  more  complete
environmental  legislation  supported
the  development   of  physical,
biological and chemical  treatment
methods for hazardous wastes.  There
is still  a  need,  and this  will
always  exist,  to  find  new  ways
because the most predominant present
methods of hazardous  waste treatment
(listed below),  as,  for example,
they  are used  in  the  United States,
will   be  neither sufficient nor
allowed  in a  couple of  years, or
they  will become too  costly:

   - indiscriminate  dumping
   - drum dumping
   - ocean dumping
   - pooling for evaporation
   - encapsulation and fixation
   - placement into lined  disposal
      sites
   - spraying into the ground
   - mixing with soil
   - deep well injection
   - ocean burning
   - incineration
    Emphasis  is currently placed  on
developing "new" advanced methods,
still dealing  with the three so-
called "end-point"-solutions,  which
are as follows:

a)  Destruction of the hazard or the
    hazardous  waste.    This  is
    achieved either by  biological
    degradation   methods   or  by
    thermal  processes such  as  high
    temperature fluid wall  (HTFW)-,
    fluid bed-,  or  molten  salt-
    incineration;   pyrolytic
    processes; plasma arc reactions;
    microwave plasma  technologies;
    wet  air oxidation  (WAO);  or
    supercritical   fluid  (SCF)
    oxidation;   among   other
    destruction technologies.

b)  Reduction of the hazard or the
    hazardous waste.  There  is  much
    work done in developing new chemical
    or biological methods.  The  most
    outstanding results seem to be found
    in the field of enzyme technologies
    and genetic  engineering  ('gene
    splicing')  for development  of new
    microbial      strains which  are
    capable   of degrading  previously
    recalcitrant organic chemicals; but
    progress  has  also been achieved in
    development of chemical  processes
    that reduce the hazard and danger of
    heavy metal wastes (as, for example,
    the conversion  of  hexavalent-
    chromium  waste  to the  trivalent
    state) or that involve  the oxidation
    or hydro!ization  of organic
    compounds.  Other examples could be
    the  use  of  reduction  agents,
    different  chemical  treatments,
    photolysis, and gamma irridation
    methods.   But physical  processes can
    also be  used  to reduce the hazard—
    let us   just take  as  examples
    distillation,  absorption,   and
    extraction  by  supercritical  fluids;
    as well  as  different  membrane
    processes such as  ultrafiltration,
    reverse  osmosis,  dialysis  and
    electrodialysis,  and  freezing and
    crystallization processes.

c)  Isolation  of hazardous wastes.
    Progress  has  also been achieved in
    the  isolation  of hazardous   wastes,
    which has to be regarded as the most
    traditional  and coventional  of end-
    point treatment methods. There have
    been achieved  better knowledge and
    safer methods  of disposing  wastes,
    either  in  secure landfills  or by
    neutralizing,  solidifying,  or
    encapsulating the  wastes  in  cement
    or pozzulano-based  materials,
    thermo-plastic materials,  organic-
    polymers,   or  glassification
    materials;  but  there is still  a
    great deal  of uncertainty about the
    long-term effects of these methods.

    But even in  achieving these end-
points there  will, in almost all  cases,
remain the need for  disposal  or
isolation of  residuals,  and there will
always be an  emission of stack gases and
                                  388

-------
effluents,  because  none  of  the
treatment methods can obtain a zero
level  of pollution.

Recycling and Cleaner Technologies  as
Farsighted Means of  Hazardous Waste
Management

    Many  of  the above  named  new
methods  for  the  treatment of
hazardous wastes  are  the result of
the development or  adaption of  new
industrial production methods or
reactor designs, as in the case of
fluid  bed reactors.  By economically
and  technologically  improving
production methods, technologies,
and systems, people became more and
more aware of minimizing production
spills and wastes—and  one of the
means  to achieve this  was recycling.

Recycling

    Recycling has for a long  time
been an  integral part of  resource
management,  adding  to materials
supply  and  alleviating  resource
depletion.  But in the recent years
recycling has had an important role
as a means in waste management, and
there  are  good   chances   for
establishing recycling  as a means of
hazardous waste  management—though
there are still  a  lot of  barriers
and constraints.

    But  what  is  recycling?   Well
knowing  that there are a lot of
diverging definitions,   I  will
explain,  by the next figures,  which
possibilities  there  are  to  use
materials physically again,  to
recycle them.
Figure  2.    Recycling Possibilities.
             Source:  Muller
   raw material A
    raw material BI
:              reduction B[   4use BI  »
                      I    i	 __    _ _ f1"'""" ""••
    We all  know the principle of reusing
a product for its original purpose,  such
as a returnable bottle, or a material
for its original  purpose (glass from
broken bottles),  and we also  know a  lot
of other materials which are used  in
such  recycling  processes.   Scrap,
rubber, plastics, paper and glass  are
examples   for   these  well-known
processes—but we all know as well  that
much  more  could be  done in  these
traditional  fields  of   recycling
activities!

    But recycling  has  also  become  an
important  part  of  hazardous  waste
management  activities — either  for
directly regaining economic  value or by
combining  environmental  needs with
recovery activities.   Recycling of waste
oils,  asphalts,  solvents  and acids  are
well  known,  but not fairly well used
examples for recycling activities in the
field  of hazardous wastes.

    It is obvious that the possibilities
for a direct recycling  of hazardous
wastes,   both  technologically   and
economically, seem to be rather limited
because of  the  increasing complexity of
many production processes and production
wastes.  But there  are still  a  lot of
often  surprising  possibilities—for
example the  recycling of petrol from the
petrol-laden air which  is emitted under
each tankfilling operation.

    Recycling as a means of hazardous
waste management  has become of greater
                                 389

-------
importance  for  those activities
which have been called "recovery".
Let us just look at some examples
which show that there  are a  lot  of
possibilities which  can be  used  in
an economic way:

  - In  the electronics industry you
    can  find  a  lot  of  copper
    containing wastes from  excess
    copper which is  removed by means
    of   hydrochloric  acid.    This
    waste liquid could  go to special
    hazardous waste  treatment plants
    to  end up as filter cakes which
    have   to   be  deposited   in
    controlled landfills.   But  on
    the other  side is copper,   a
    micro-nutrient  in  fertilizers,
    where  the  Cu-requirement  is
    approximately 01%—and therefore
    some fertilizer producers are
    recycling  the copper  from
    copper-containing wastes from
    the  electronics  industry.

  - Another example  could   be the
    recirculation of process  waters
    from  the  production  of  glass
    wool.   These  waters contain
    hazardous organic compounds and
    are now  recirculated for the
    production of  a binding agent
    which is used for the production
    of  glass wool.

  - Acid wastes from sulphate based
    titan-dioxide production  can  be
    recycled in  an energy  saving
    manner.  Thus it can be achieved
    that no acid  wastes have to  be
    dumped in the ocean.

  - Bottom  products from  the
    distillation  of  solvents
    containing wastes from the paint
    and  colour  industry  can  be
    recirculated  as  fillers  in
    certain paint types.

  -Pickling  acid  wastes  and
    electrolytic pickling baths from
    the   aluminum   industry  are
    hazardous wastes  which  can  be
    recovered  and converted  by
    special  combinations of these two
    waste  streams,  whereby  sodium
    aluminate  (NaAlC^h   aluminum
    sulphate-Al9(804)3- and   Glauber's
    salt (miraEil i'te",
    can  be  produced.
NaS04.10
H2S04)
    There are a lot of other examples
for the recycling of materials by the
recovery of  hazardous wastes—but it
must be said  that there is still a need
for further development.

Cleaner Techno!ogies

    The  development  of  extended
recycling and recovery  processes  was the
first step on the way  to  a  new  concept
in  managing  waste  problems--cleaner
technologies,  known  also  as  low-waste-
technologies.

    Though there are many  differences in
defining this term,  cleaner technologies
should be regarded  as  those production
measurements  which  reduce the  quantity
and the hazard of all types of emissions
of  a  production cycle,  which  can be
illustrated by the following figure:

    It  is  obvious  that  a  recycling
policy just  covers  those  production or
product wastes which have occurred,
while cleaner technologies try  to avoid
the origin of wastes and  emissions,  as
far as possible, by regarding the whole
production and product  cycle.

    How can this be  achieved?

    There are three principle ways of
reducing the level of emissions and
wastes:

Figure 3:Cleaner Technologies and the
           Production  Cycle.
           Source:   Miljostyrelsen

a)  Choice of other  or alternative raw
    materials
b)  Development of new  processes
c)  New or alternative  product design
    ada:   It  is  a  basic principle  that
those raw  materials which contain fewer
                                  390

-------
    Figure 3
                          frecyc-^
                            ling
V7c.t. = cleaner technology
       "Environment"
      391

-------
pollutants   result  in  fewer
environmental emissions;  but also
the choice of alternative materials
with  the same  function  in  the
production process will make a given
technology   cleaner.     These
substitution processes  can  be
divided  into physical  (such as
replacement of transformer  oils by
PCB-free  oils),  quantitative  (such
as  using thinner  coatings)  or
functional  (as in replacement of
solvents in  paints  by  water)
substitutions.

    ad  b:  The development of new
processes is a very  important part
of   a   cleaner   technology
conceptualization,  and  there  are
numerous examples  of  cleaner
technologies  avoiding  airborne,
liquid or solid hazardous wastes:

  - Development of a non-polluting
    process for recovering 99.99%-
    pure  lead  from  discarded
    batteries.   The  method  reduces
    lead  and  sulphur  dioxide
    emissions  by avoiding smelting,
    the  conventional   way  of
    recovering  lead from spent
    batteries.  The new process  uses
    electrolytic   melting  and
    subsequent chemical/electroly-
    tical operations.

  - Development  of  an   (as  yet
    unpublished)  ion-exchange
    process,  which converts waste
    gypsum   (CaSO^) and  cheap
    potassium chloride  into  the
    valuable  fertilizer component
    potassium  sulphate  (KgSO^) and
    harmless  calcium   chloride
    (Cad?)-   This process  gives a
    profit   compared   to   the
    conventional  production  and, at
    the  same time, gypsum  waste is
    avoided and  the  heavy metals
    from  the  proceeding  rock-
    phosphate  treatment process--
    especially copper, lead, zinc,
    cadmium   and  mercury--can  be
    precipitated.
  -  Development of alternative spray-
    coating  processes or  production
    technologies  for fly-ashes  or
    different  filter dusts in order to
    minimize solid hazardous wastes.

    ad  c:  New or alternative product
design   includes   substitution   of
function,  materials,   and construction.
These substitution methods are important
in hazardous waste  management,  as  the
following examples show:

  -  substitution for mercury-containing
    batteries  of zinc-oxygen  batteries
    to  avoid  mercury emissions from
    refuse incinerators

  -  development  of  water-based  and
    solvent-free paints and colours

  -  development  of  chlorine-free
    bleaching  processes in the pulp and
    paper industry

  -  replacement of cadmium in colouring
    pigments

  -  substitution for PCB-containing oils

  -  substitution  for  halogenated
    hydrocarbons as  propellent, sponging
    or foaming agent

  -  development  of new  construction
    principles and materials

    It    is   apparent   that  the
conceptualization  of  cleaner
technologies  is  very complex, and that
the  development  of new raw  materials,
production processes or products will
take time, as the following table shows.
                                 392

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Figure  4:   Levels of Substitution
             and Associated Develop-
             ment Times.
             Source: Schlabach
                            Development
                              time
       Level
1  Noninteractive material substitutions       1 - 3
  Assembly or component change
2  Development of new material or chemical    3-4
   process
3  Interactive materials substitution         4 — 5
  Electronic technology change
  Subsystem or small system development
4  Systems of reasonable complexity         ~7
5  Complex weapon systems             ~10
6  Telephone exchange technology          ~13
7  Time for scientific discoveries to find large-   ~15
   scale technical application


    Many  will  claim that all new
developments concerning  products,
production processes,  and  emission
equipment can be  regarded as cleaner
technologies  because of their effect
on reducing emissions  and  spill
products,  and as a consequence  of
minimizing production  costs—but
isn't that  too  easy to  ease our
consciences?

    Cleaner  technologies  should  be
regarded as those technologies which
are a real and jntended  alternative
to existing  technologies, from  an
environmental  point of view; the
environmental benefits should not  be
regarded  as an accidental by-
product!

RecyclIng andCleaner Techno!ogy  in
Denmark
                                     law,  which was passed  in the extended
                                     form  including  cleaner  technologies  by
                                     October 1, 1984,  can be  given:

                                     a)  We feel  that recycling activities
                                         have been promoted very much by this
                                         law, and that information activities
                                         are  of  great  importance  to  the
                                         attitude of  the  population  and  the
                                         result of the recycling activities.

                                     b)  The importance of easy,  consumer-
                                         oriented  collection systems  is
                                         evident  both  for  households  and
                                         industries.    This  is  a  very
                                         important factor for separation  and
                                         recycling  activities  concerning
                                         hazardous wastes.

                                     c)  It  takes  time  to  develop and
                                         introduce  cleaner technologies  in
                                         the industry,  especially in  small
                                         and medium sized enterprises.

                                     d)  There  is  a  great  interest   in
                                         participating in  our  recycling-and
                                         cleaner technology program,  and  we
                                         feel  that  we  are  promoting this
                                         concept a lot.  We  hope to  be able
                                         to  extend  our  activities  more
                                         towards hazardous  wastes.

                                     e)  A great incentive, or press,  for  the
                                         promotion of  cleaner technologies is
                                         given  by   environmental   law
                                         activities—and it always turned  out
                                         that cleaner  technologies  are paying
                                         for themselves.

                                     SUMMARY AND CONCLUSIONS
                                     1.
    Denmark has  passed  a  new  law on
recycling  and  cleaner technology
which enables the state,  to support
all types  of  recycling activities
concerning  materials.   On the other
hand,  it  is  possible to promote
cleaner technology by  financing  or
supporting  research  and information   2.
activities  or  research  and
demonstration  projects.

    It would be  inappropriate to try
to  explain and  discuss  this  law   3.
here.  Some experiences with  this
                                    393
Increasing  amounts  of  wastes,
increasing  hazards,   and  new
technological   developments  make
solving future  problems by new  way
of  managing   hazardous  wastes
inevitable.

Conventional  ways of treatment will
become more  and more insufficient
both    economically   and
environmentally.

Recycling is  becoming an  integrated
part of the industry's activities,

-------
but  there  are  still
unsolved  problems.
                    a  lot  of
4.
Cleaner  technologies  offer  new
and non-traditional  possibili-
ties for solving hazardous waste
problems  by  regarding   the
complete  product life cycle.
5.
It
cleaner
   seems  that  all recycling and
        technology activities
can  be ensured  by   law  and
financial support measurements
by state  authorities.
REFERENCES
1.
Curran, Linda H.:  New Solutions
To Industrial Waste Management,
in:   Environmental  Progress,
Vol.  3, No. 2,  May 1984.

Lovgren,  Peter:   The  Danish
System,  in:  Proceedings of the
1st  International Symposium  on
Operating  European  Centralized
Hazardous  (Chemical)  Waste
Management Facilities,  Odense,
Denmark, September 1982.
    M a c k i e,
    Kathleen:
    Chemical
    1984.
           Jay  A.;   Niesen,
          The Alternatives, in:
         Engineering, Auag. 6,
4.   Miljostyrelsen (NAEP): Recycling
    and  Cleaner  Technologies,
    Copenhagen, Oct.  1983.

5.   Muller,  Klaus:  Altolverwertung
    (Reuse  of  used  oils),  Erich-
    Schmidt-Verlag,  Berlin,   W.
    Germany,  1982.

6.   N.N.:    Lead-recovery  Route
    Eliminates   Smelting,  in:
    Chemical Engineering, Aug. 20,
    1984.

7.   N.N.:    Recy