\"
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 2d460
EPA-SAB-EEC-90-010
OFFICE OF
THE ADMINISTRATOR
March 27, 1990
Honorable William K. Reilly
Administrator
U.S. Environmental Protection Agency
401 M Street, s.W.
Washington, D.C. 20460
Dear Mr* Reilly:
The Science Advisory Board has completed its review of the
Office of Research and Development's (QRD) Municipal Waste
Combustion Ash Solidification/Stabilization (S/S) research program.
It was based on briefing materials and discussions with staff in
a review meeting conducted on September 18-19, 1989 by the
Municipal Waste Combustion Ash Subcommittee (MWCAS) of the
Environmental Engineering Committee (EEC), and on selected
materials provided to the MWCAS in May and June, 1989,
. The issues reviewed by the Subcommittee were (1) appropriate
testing procedures to be applied to S/S ash products and reuse
products made from S/S ash to determine long-term environmental
effects, and (2) methods of testing to determine the bioavail-
ability and toxicity of S/s ash products.
The OSD staff are to be complimented on their formation and
effective use of a Technical Advisory Panel (TAP), The TAP
provided focused technical input on the best applications of GRD's
limited funding,
Highlights of our findings and recommendations for long-term
effects research are as follows. The highly variable array of
ashes fr
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Bioavailability and toxicity should be examined as two
distinct and separate phenomena. While limited in scope, bioassays
can be used effectively for making relative comparisons of the
toxicities of leachates derived from various ashes and products,
Extensive bioassay testing will be required, and no single bioassay
procedure can adequately assess biological effects of residue reuse
or disposal alternatives.
The Municipal Waste Combustion Ash research program should be
reviewed for adequacy of funding. This program should emphasize
front-end prevention at least as much as back-end treatment.
Additionally, the potential risks associated with ash disposal
should be compared with long-term risks associated with alternative
municipal solid waste disposal options.
We appreciate the opportunity to provide advice to the Office
of Research and Development's municipal waste combustion ash
research program on this important topic, and look forward to your
response.
Sincerely,
Raymond C. Loehr, Chairman
Executive Committee
Science Advisory Board
Richard A. Conway, Chairman
Environmental Engineering Committee
Science Advisory Board
Ben B. Evring, JEhairman
Municipal Wa^te Combustion Ash
Subcommittee
Science Advisory Board
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U.S. Environmental Washington, DC
Protection Afl*ncy EPA-SAB-ESC-90-010
Report of the Municipal Waste
Combustion Ash Subcommittee
Review of the ORD Municipal
Waste Combustion Ash Solidification/
Stabilization Research Program
A SCIENCE ADVISORY BOARD REPORT March 1990
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EPA-S&B-EEC-9Q-01.Q
REPORT Of TIE MUNICIPAL WASTE COMBUSTION ASH SUBCOMMITTEE
OF THE ENVIRONMENTAL ENGINEERING COMMITTEE
REVIEW OF THE OFFICE OF RESEARCH AND
DEVELOPMENT'S MUNICIPAL WASTE COMBUSTION ASH
SOLIDIFICATION/STABILIZATION RESEARCH PROGRAM
MARCH, 1990
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NOTICE
This report has been written as a part of the activities of
the Science Advisory Board, a public advisory group providing
extramural scientific information and advice to the Administrator
and other officials of the Environmental Protection Agency. The
Board is structured to provide a balanced, expert assessment of
scientific matters related to problems facing the Agency. This
report has not been reviewed for approval by the Agency,* hence,
the comments of this report do not necessarily represent the views
and policies of the Environmental Protection Agency or of other
Federal agencies. Any mention of trade names or commercial
products does not constitute endorsement or recommendation for use.
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ABSTRACT
The Municipal Waste Combustion Ash Subcommittee (MWCAS)
reviewed the Agency's municipal waste combustion ash
solidification/stabilization (S/S) research program. The issues
reviewed were (1) appropriate testing procedures to be applied to
S/S ash products and reuse products made from s/S ash to determine
long-term environmental effects, and (2) methods of testing to
determine the bioavailability and toxicity of S/S ash products.
The Subcommittee's findings and recommendations for long-term
effects research dealt with test routines and leach testing
research, focusing upon the properties of the leachate and the
physical and chemical characteristics of the solid matrix in order
to define the breakdown and exposure of surfaces of stabilized
products, the need to evaluate weathering, and for some reuse
alternatives, of dynamic abrasion and erosion, other findings and
recommendations dealt with the effect of salts, microbial activity
and swelling of ash upon the long-term usefulness of concrete
products, and the usefulness of deterministic models of transport
mechanisms to assess relative effectiveness of the various S/S
treatment processes.
Highlights of the findings and recommendations for
bioavailability and toxicity dealt with examining bioavailability
and biotoxlcity as two distinct and separate phenomena, the
effectiveness of bioassays for making relative comparisons of the
toxicities of leachates derived from various ashes and products,
the need for extensive bioassay testing, and the finding that no
single bioassay procedure can adequately assess biological effects
of residue reuse or disposal alternatives.
Key Words: Ash, Ash Research, Municipal Waste Combustion Ash,
Ash Solidification/Stabilization
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MUNICIPAL WASTE COMBUSTION ASH SUBCOMMITTEE
ENVIRONMENTAL ENGINEERING COMMITTEE
of the
SCIENCE ADVISORY BOARD
Chairperson
Or. Ben B. Ewing, Professor of Environmental Engineering, institute
for Environmental Studies, University of Illinois
Members and Consultants
Mr. Allen Cywin, Consultant, Savannah, Georgia
Mr. George Green, Manager of Electric Operations Services, Public
Service company of Colorado, Denver, Colorado
Dr. Rolf Hartung, Professor of Environmental Toxicology, School of
Public Health, University of Michigan, Ann Arbor, Michigan
Dr. William Haun, Director of Engineering, General Mills, Inc.
(Retired), Maple Grove, Minnesota
Dr. Ishwar P, Murarka, Program Manager for Land and Water Quality
Studies, Environmental Division, Electric Power Research Institute,
Palo Alto, California
Dr. Walter M. Shaub, Technical Director, Coalition on Resource
Recovery and the Environment, U.S. Conference of Mayors,
Wash ington, DC
Dr. Thomas T. Shen, Senior Research Scientist, New Yorlc state
Department of Environmental Conservation, Albany, New York
Science Advisory Board Staff
Or. K. Jack Kooyoomjian, Designated Federal Official, Science
Advisory Board (A101F), U.S. Environmental Protection Agency,
Washington, DC 20460
Mrs. Marie Miller, Staff Secretary, Science Advisory Board
Dr. Donald G. Barnes, Director, Science Advisory Board
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TABLE OF CONTENTS
1. 0 EXECUTIVE SUMMARY. , ........ 1
2 . 0 INTRODUCTION ...» ............................ 2
3.0 LONG-TERM EFFECTS........... ...................... 3
4.0 BIQAVAILABILITY/BlGTOXieiTY .7
5. 0 OTHER RELATED ISSUES 10
APPENDIX A - THE CHARGE TO THE SUBCOMMITTEE....... . . . 12
APPENDIX B - GLOSSARY OF TERMS AND ACRONYMS. 13
APPENDIX C - INITIAL REVIEW DOCUMENTS 14
APPENDIX D - RESOURCE MATERIAL , .15
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i-0 EXECUTIVE SUMMARY
The Municipal Waste Combustion Ash Subcommittee (MWCAS) of the
Science Advisory Board's (SAB) Environmental Engineering Committee
(EEC) reviewed the Agency's municipal waste combustion ash
solidification/stabilization (S/S) research program. The issues
reviewed were (l) appropriate testing procedures to be applied to
S/S ash products and reuse products made from S/S ash to determine
long-term environmental effects, and (2) methods of testing to
determine the bioavailability and biotoxicity of S/S ash products.
Highlights of the findings and recommendations for long-term
effects research are as follows:
a. The highly variable array of ashes from many combustion
facilities dictates that test routines developed must apply to the
behavior of various products of different ashes.
b. The research program should address both the properties of
the leachate and the physical and chemical characteristics of the
solid matrix in order to define the breakdown and exposure of
surfaces of stabilized products.
c. There is a need to continually evaluate the effect of
weathering, and possible dynamic abrasion and erosion, the effect
of salts, microbial activity and swelling of ash, for evaluation
of the long-term effect of use of S/S products for some purposes
such as road base or building materials.
d. Deterministic models of transport mechanisms may be useful
to assess relative effectiveness of the various S/S treatment
processes.
In discussing bioavailability and toxicity, the Subcommittee
recommendations the followingt
e. Bioavailability and toxicity should be examined as two
distinct and separate phenomena.
f. While limited in scope, bioassays can be used effectively
for making relative comparisons of the toxicities of leachates
derived from various ashes and products,
g. Extensive bioassay testing will be required, and no single
bioassay procedure can adequately assess biological effects of
residue reuse or disposal alternatives.
The Subcommittee is concerned that the Municipal Waste
Combustion Ash research program is inadeguately funded. The
Municipal Waste Combustion Ash program should emphasize front-end
prevention at least as much as back-end treatment. Additionally,
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the potential risks associated with ash disposal should be compared
with long-term risks associated with alternative municipal solid
waste disposal options.
The Office of Research and Development (QRD) has established
and used a Technical Advisory Panel (TAP) to guide its management
of the S/S program to effectively use the very limited resources
of money and manpower.
2.0 INTRODUCTION
At the request of the Office of Solid Waste (OSW), the Office
of Research and Development (ORD) has instituted a research program
on municipal solid waste (MSW) disposal and particularly on the
handling, disposal and possible reuse of ash produced by the
incineration of MSW. While this is a continuing program, the
current research is focused on the solidification and stabilization
of municipal waste combustion ash (S/s)« Phase I of the program,
which is already in progress, is a demonstration of the technical
feasibility of various methods of S/S and characterization of the
short-term environmental behavior of the products of S/S.
The Science Advisory Board was aslced to review the Municipal
Waste Combustion Ash (MWCA) research program and assigned the
review to the Environmental Engineering Committee (EEC). The EEC
has established a MWCA Subcommittee, members of which are listed
in this report.
The Subcommittee (MWCAS)has been charged with (a) a continuing
review of the ORD MWCA research program, and (b) more immediately,
consideration of two issues related to the current S/S
demonstration. These two issues, considered at the initial meeting
of the Subcommittee, were (1) the appropriate testing procedures
to be applied to the S/S ash products and reuse products made from
the S/S ash to determine the long-term environmental effects, and
(2) appropriate methods of testing to determine the bioavailability
and "biotoxicity" of S/S ash products.
The issues to be considered at the initial meeting were worked
out during an August 17, 1989 teleconference between EPA personnel
of the ORD and the Risk Reduction Engineering Laboratory (REEL)
together with members and staff of the EEC. on September 18 & 19,
1989, the 1WC& Subcommittee held its initial meeting in Washington,
DC to review the current MWCA research program and consider the two
issues of long-term effects and bioavailability/toxicity. The
documents which had been made available to the Subcommittee and
were reviewed by its members prior to that initial meeting are
listed in Appendix C. During the meeting, the MWCAS was provided
copies of the briefing materials used by Mr. Carlton C. Wiles of
the RREL.
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The ORD staff has organized a Technical Advisory Panel (TAP)
consisting of approximately 26 experts from various agency and
interested organizations and has used the group effectively in
guiding the management decisions for the program. The Agency staff
is to be complimented for their use of peer review for its research
program.
3,0 LONG-TERM EFFECTS
The first issue the MWCAS considered had to do with the
testing required to enable the prediction of long-term
environmental effects of products made from MWC ash residue. The
MWCAS made the following observations:
a. Any test routine used to predict long-term effects must
apply tothebehaviorofvarious products of different ashes .from
different incinerators _ produced,by different S/S processes, .under
both.. dj.s|3o.saj.. conditions,, and, for different _reu_se§_. __A _single-site
assessment is not expected. tobe adequateJso provide, data which are
applicable to the highly_variable array of ashes from the^ many
municipal combustion facilities.
The selection of an ash management practice, a S/S process,
or use of ash products depends largely on ash characteristics. Ash
(fly ash, bottom ash or combined ash) should be tested for quality
and variability of the ash at several sites. The phase I program
is limited to ash from a single site. Therefore, the results may
not be broad enough to be applicable to the highly variable array
of ashes from the many municipal combustion facilities.
The criteria for site selection should include data availa-
bility, such as the approximate waste input composition, the
incineration system design and operating conditions, and the
performance of the air pollution control device(s) used with the
municipal waste combustor. Such data are valuable for under-
standing and managing the overall solid waste and incineration ash
programs.
Tests to be used will depend on what products are being
tested, what process was used to produce them, and what scenario
is to be mirrored. The facility used to produce the ash, the air
pollution control devices installed and the performance of the
devices and the process by which the ash is treated for S/S should
be identified and described. Fly ash will be the most difficult
residue for which to predict long-term behavior, because that
behavior will depend significantly on ash characteristics
determined primarily by the combustion conditions and secondarily
by the air pollution control devices which captured the ash.
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Although present practice generally provides for combined ash
disposal, the research should be directed toward evaluating S/S
processes separately on fly ash and bottom ash, as well as combined
ash. Certain S/S processes might very well be more applicable to
either the fly ash or bottom ash long-term disposal problem.
b. Addressing long-term (and short-term) environmental
behavior requires a fundamental understanding of _geochemica!I
reactions expected to cause the leaching: and mobilization of
chemicals Contained in the residues._ It is therefore recommended
that the research plan focus on the solid phase, including
identifyingthe original quantities.chemical speciesandphysical
forms of inorganic chemicals of interest. Furthermore,laboratory
tests should be conductedtodevelop data for specifying the
mechanistic basis that would quantitatively deJfine the breakdown,
the exposure of surfaces and resulting releases _of :the _chemica_ls
from the s tab i1 i zed products«
To address long-term environmental behavior of products
prepared by S/S of MWCA, the EPA ORD plans to carry out several
laboratory tests and measure concentrations of chemicals in the
aqueous extracts. These tests span from regulatory extraction
tests (i.e., TCLP) to monolith leach tests for estimating
diffusion-dominated, transfer of chemicals into the aqueous phase.
In addition to the leaching tests for untreated and treated MWCA,
several physical tests will also be carried out. The scientific
principles underlying the long-term behavior of chemicals in waste
are intimately connected to dissolution reactions between solids
and liquids. Therefore tests on the solid phases are needed in
addition to leachate solution tests. An accurate understanding of
these reactions and quantification based on data from laboratory
experiments can provide a capability to predict release of
chemicals from MWCA products.
Two options are available to address the science and the data
needs for long-term predictions. The first approach is fundamental
and provides a mechanistic understanding of applicable equilibrium
and kinetic reactions,* but it uses relatively short-term input
data. The second approach is empirical and uses statistical
correlations of short-term nature. However, the only realistic
option to predict long-term behavior is the fundamental approach
using models with good empirical and necessarily short-term input
data. The SPA's current research plan appears to utilize the
second approach. However, analysis of the data to be gathered
through equilibrium speciation models »such as MINTEQ and ECHEM
(Appendix D, references 4 and 14) can offer insights into the
applicability of the mechanistic approach to predicting leaching
from the products of MWCA. The aqueous concentration measurements
alone will not yield the understanding necessary for predicting
long-term environmental behavior.
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It Is recommended that the research include an analysis of the
solids for the explicit purpose of identifying quantities and types
of solid phases of the inorganic chemicals of interest to the
Agency. For a long-term behavior prediction,, not only does one
need to have a specific identity of solubility/dissolution
reactions, but also one needs to know how much of the total amount
of the chemicals would actually be available for leaching and how
this relates to the receptor environment, one additional challenge
in this research program is the ability to develop testing
procedures and data for the mechanistic basis that would
quantitatively define the breakdown and exposure of surfaces of the
stabilized products.
c. There is a need to continually evaluate the effect of
weather ing and, for some reuse alternatives, the dynamic effect, of
abrasion anderosion, because the physicalchanges ofthematrix
may alter the rate of JLeachinqof the resultant const ituent.sfrom
the matrixand also the mechanical integrityof the material.
The stability or mobility of the reuse products (such as for
roads, construction and various beneficial uses in the energy
industry) should continue to be evaluated both with and without
weathering, abrasion, and erosion. The effect these processes have
on the surface area, and the surface properties of the solid matrix
must be considered. This reinforces the need for understanding
both the chemistry of the aqueous phase and the physical and
chemical nature of the solid matrix.
d. Whilemathematicaltransport and fate models may not be
quantitatively predictive, they may still be useful for determining
which contaminants warrant further study of their potential
environmental impact^ as .well as for determining relative
effectiveness of the various S/S_ treatment: processes«_
The Subcommittee questions whether existing models for trans-
port and fate of contaminants in environmental media can be used
to quantitatively predict the migration of chemical constituents
from stabilized ash. Also, difficulty in estimating the rate of
release of contaminants from the solid phase makes the input data
for these models uncertain. Therefore, it is very doubtful that
the prediction will provide the basis for reliable estimates of the
exposure and health risk to target populations. Still, it is
believed by the Subcommittee that some of the better transport
models could be very useful in determining which contaminants are
sufficiently mobile to warrant further study. These models might
be used to analyze the data to indicate the relative effectiveness
of the S/S treatment processes. If one cannot quantitatively
estimate the mobility of chemicals leaching from the ash product,
one might, at the very least, determine the relative mobility of
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the constituents.
e. Better predictions of long-termbehavior can be_ madefor
certainchemicals than for others. Chemicalsshould toeidentified
and focused upon to fill data craps.
The scientific basis for predicting the leaching of inorganic
chemicals is incomplete for most trace elements. Although some of
the major constituents (e.g., calcium and silicon) have well
defined dissolution/precipitation chemistry, similar reliable
foundation needs to be developed for a target set of trace
elements, it is recommended that selected elements be chosen and
research focused on the development of the data to fill the key
data gaps hindering capability to accurately predict release of
chemicals from residues or stabilized products.
Since this research is to fill data gaps on MWCA S/S products,
there are many constituents which are being analyzed even though
they may not be present in appreciable, or significant,
quantities. Therefore, it is very important that appropriate data
analyses be carried out on a real-time basis to identify as early
as possible those chemical constituents that need to be focused
upon.
f, Thehighsalt contentof MWCA couldlimit the long-term
usefulness of concrete for reuse. Further examination of
acceptable standards for allowable salt content of aggregate used
for reinforced concreteis recommended.
There is need to evaluate impacts of various chemical species
(e.g., sodium, potassium, calcium, zinc and chloride) on the
integrity of portland-cement concrete in those cases where the
proposed reuse of the stabilized ash is by incorporation into
concrete. Especially in the case of reinforced concrete products,
where the reinforcing steel is susceptible to electrolytic
corrosion in the presence of these ions, there is a serious need
to avoid leachable salts. These species may also affect properties
related to mechanical fracture and embrittlement.
Standards have been established for allowable chloride content
of aggregate used for reinforced concrete. The Agency should
consult with the various sources of potentially useful information.
For instance, the Highway Research Board, concrete manufacturers,
trade association standards (such as ASTM Designation; C618-89 or
ASTM Designation? C311-88) and agencies such as the Bureau of
Reclamation or the U.S. Army Corps of Engineers should be
consulted concerning allowable salt content, as well as other
specifications that may be of concern when ash is incorporated in
concrete.
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9* If microbial activity shifts the pH or the oxidation-
reduction potential fffh), the solubility of toxic metals can
change. The effects of microblal actiyity shouldbe included in
the assessment of loner-term performance.
Microbial activity may be supported by organic matter in the
ash products, or, more likely, in the milieu surrounding the ash
product in its place of use or in a monoflll. If the stabilised
ash is used for highway base and is in contact with organics-rich
soil, microbial activity nay change the pH or Eh. If MWC ash is
disposed in a monofill, the organic matter in the ash may support
some microbial activity, but it is more likely to be an inorganic
interaction phenomenon. Long-term environmental performance
assessment should take these possible changes into consideration
when studying the solubility of metals.
n* The tendency of the ash matrix to swell upon adsorption
o_f_ moisture may have long-term adverse effects on some uses of the
stabilized product. Tests should incorporate this phenomenon in
the evaluation procedure.
There is a need for incorporating some test in the evaluation
procedure to obtain an indication of expected swelling due to the
hygroscopic nature and surface features of the ash mixture. Many
road base and sub-base construction requirements cannot tolerate
large amounts of ash or S/S ash products because of this
hygroscopic property and the numerous freeze-thaw cycles.
4.0 BIQAVAILABILITY/TOXICITY
The Subcommittee was also asked to comment on possible tests
to evaluate the toxicity and bioavaliability of MWCA S/S products.
a. The committee recommends that the potential for toxicitv
and bioavailabilitYof MWCA S/S be examined as separate phenomena*
Bioavailability can be demonstrated by measuring the uptake
of the chemicals of interest into organisms. Alternatively, when
exposed organisms respond with physiological or pathological
changes, then by implication the compounds or some ingredients of
the mixture have been demonstrated to be toxic.
Existing laboratory methods are adequate to examine many
aspects of bioavailability in animals and plants under standardized
conditions (Appendix D, reference 26). However, the applicability
of these methods to complex situations, such as the bioavailability
of substances in amended soils to plants and animals, will require
validation of existing tests or the development of new
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methodologies»
b. Sioassays. like chemical analyses. are only tools in the
assessment of the potential environmental impact of disposal and
reuse alternatives.,
Prom the information received by the MWCAS, it is clear that
at present the potential roles of various forms of biological
testing for the assessment of ashes and ash products are still
poorly defined. The Agency appears to champion the position that
bioassay results can be used directly to assure the public that
appropriate policy decisions are being made. However, bioassays are
no more than tools in such assessments. The most important aspects
in the use of these tools are the specific applications and the
proper interpretation of the results.
Sometimes the most difficult decisions relate to when
bioassays are the most appropriate tools to use, given the expense
and difficulties in interpretation of many bioassay results. Thus,
to date it has not been found to be necessary to conduct bioassays
or risk assessments on other recycled resources, such as glass,
paper, and aluminum cans.
Prom a technical point of view alone, a number of issues need
to be considered to evaluate the desirability of biological
testing. In toxicity studies the responses of organisms, specific
organs, or cellular components are measured in relation to
exposures to specified concentrations of compounds or mixtures of
compounds, preferably at a graded series of concentrations. Each
biological test has specific strengths and specific limitations,
because such tests are in fact model systems where each test
examines only a specific aspect of the "real world" conditions.
Biological systems incorporate a complex system of chemical and
physical phenomena, and therefore the interpretation of tests done
on biological model systems is exceedingly complex. In any event,
bioassays need to be supplemented by leaching tests and models to
predict exposure conditions likely to be encountered in the real-
world environment.
c. No _ single Jaiojissay, procedure can adequately assess the
biological effects of residue reuse and/or disposal alternatives.
Should it be found to be necessary to conduct bioassays
because potential exposures derived from MWCA S/s materials are
deemed to be high, then no single bioassay procedure exists that
will adequately demonstrate the multiple toxicological end-points
that could potentially occur. This will reguire a battery of
bioassays using a range of test species. Ancillary problems
include the great variability of components in the ash, and
differences in the physical characteristics of the ash that will
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ultimately affect the biological availability of such components.
d. While limited in scope, bioassavs cantoeused effectivelyfor
making relative,. eompa|'lsgjns_of the taxiiiities_.of leachates derived
from various ashesand products jer_iveclfrom MWCA.
Bioassays in their broadest sense are tools that can be used
for many purposes. Among these are evaluations of comparative
toxicities of leaehates derived from various ashes and various
products of ashes. Such evaluations are much more limited in
scope, but can assess the interacting effects of components in
mixtures within the limitations of the specific bioassay procedures
utilized. Such studies can be relatively inexpensive and can be
used as an adjunct to chemical analyses.
e. Ijb Is important to establish (as a_ baseline) the -background
bioavaliability of the .e.on.ajcit_uentsjpf_Jjit.eres.t_ for the environment
into., which. ^e._g./Sr_igg£Aj_progMCt-.s._ are to be utilized.
Absent any credible baseline information, expected
perturbations to the ambient environment due to S/s MWCA
constituents cannot be established. The assessment of potential
risks associated with ash and products derived from ash needs to
be compared with an assessment of the background concentrations of
the same compounds that may already be present due to natural
sources or due to normal human activities. This approach is
encouraged as an adjunct activity, because comparative risk
assessments have a much firmer scientific basis than absolute risk
assessments.
f, Another approach is_ to base theapproval, of reuse and .disposal
alternatives on conf irjiat j.on that the leachate from. S/jS jaroducts
meet some multiple of driolcing Mater standards or Mater cpaajjlty.
criteria.
If realistic methods could be developed which produce
conditions similar to those produced under "real world" conditions,
then a comparison of the contaminant concentrations found in the
leachatea with published water quality criteria and drinking water
standards would allow an initial evaluation of the relative
toxicity for the protection of aguatic life and human health* The
Agency does have considerable information on bioconcentration, and
this phenomenon has been made an integral part of the present water
quality criteria. It should be noted that the bioconcentration
issue has been found to be important for highly hydrophobia organic
chemicals, but is generally not important for inorganic chemicals,
with a few notable exceptions (e.g., mercury).
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5.0 OTHER RELATED ISSUES
a. The SubCQimitteeis concerned that the,level, of funding forithe
municipal waste combustion ash research program may be inadequate.
It is estimated that at present there are approximately 200
municipal waste incinerators in operation or under construction and
that over 100 municipal waste incinerators are under procurement
or in the planning stages. The construction cost of each is in the
range of tens of millions to several hundreds of millions of
dollars. This represents a national investment of perhaps $17
billion (See Appendix D, references 29 and 30 and note below) .
Each of these 200 municipal waste incinerators is facing the
problem of what to do about its ash residues. The over 100
municipal waste incinerators yet to be built will also face these
same problems with the ash residues. The estimated ORD budget for
the Phase I S/s research program is less than $1 million. It seems
inadequate that only 0.006 percent of the Federal component of the
public investment is being devoted to solution of the ash disposal
problem within the ORD budget.
At its initial meeting, MWCAS heard presentations from persons
associated with state agencies and academic institutions in New
York and in Florida. It was learned that these states are each
devoting more financial resources to MWCA research than is EPA.
The Agency should continue to leverage funding its research
programs with state and private entities.
We recommend that funding for MWCA research be reviewed for
adequacy in light of the above. We also recommend that the Agency
track significant federal, state, municipal, and private sector
activities in municipal waste combustion.
NOTE: Personal communication of March 20, 1990 Between Mr.
Steven Levy of the USEPA Office of Solid Waste with Dr.
K. Jack Kooyoomjian of the Science Advisory Board staff.
Combined Total ApproKL. Cost jkpprgx..Total
Capacity To Construct Cojpstruction
Facilities llymber fTons/Dav) Per Ton capacity costlBillions)
In Operation 167 91,705
Under Con-
struction 39 40,586
Under Pro-
curement 63 56,086
In Planning
Stages
51
$75,000
$100,000
$125,000
$6,9
$4.06
$6.26
Total = $17.22
10
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b. The municipal _wastecombustionash research, should emphasize
front-endprevention instead of back-jmd treatment.
MWC ash quality is the Jcey to proper ash disposal or reuse
that affords adequate protection to the environment* Ash quality
differs among fly ash, bottom ash, and combined ash. It varies
with input waste characteristics, design and operating conditions
of an incinerator, and to some extent to the air pollution control
device used. Obtaining a good knowledge of highly varying ash
quality could, be difficult and costly. However, if undesirable
chemical or consumer products in the waste can be prevented by
front-end removal activities, then the quality of ash could be
improved for either disposal or reuse without exceeding
environmentally acceptable levels or performance specifications for
ultimate use end-products.
c. Potentialrisks associated withashdisposal should be compared
with risksassociatedwith alternative municipal, solid waste
d.is_BQ.sal options.
The risks inherent in municipal waste incineration, including
the ancillary risles due to disposal of residuals from incineration,
are receiving a great deal of attention by the public and the
Agency. In many ways the concerns seem to be on a mutually
reinforcing spiral. The anticipation appears to be that all
aspects associated with the incineration process would be free of
health risks. At the same time it is clear that other legitimate
solid waste disposal management options for the handling of
municipal waste, such as recycling and landfilling, have not
received the same level of scrutiny as ash disposal options. This
appears to be due to a lack of data and due to preconceived notions
that these processes are relatively free of risks so that they do
not merit investigation. This sentiment may be misplaced and may
lead to inappropriate actions relating to the minimization of risks
associated with waste disposal options.
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APPENDIX A - THE CHARGE TO THE SUBCOMMITTEE
Based on materials submitted to MWCAS and conference with Agency
personnel, the following charge for the Subcommittee evolved;
a) continuing review of the ORD MWCA research program, and
b) consideration of two issues related to the current s/s
demonstration. These two issues, considered at the initial
meeting of the Subcommittee, were (1) the appropriate testing
procedures to be applied to the S/s ash products and reuse
products made from the S/S to determine the long-term
environmental effects, and (2) appropriate methods of testing
to determine the bioavailability and "biotoxicity" of S/S
products.
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APPENDIX B - GLOSSARY OF TERMS AND ACRONYMS
ASME- AMERICAN SOCIETY OF MECHANICAL ENGINEERS
EEC- ENVIRONMENTAL ENGINEERING COMMITTEE OF THE
SCIENCE ADVISORY BOARD
ECHEM- EQUILIBRIUM CHEMISTRY (GEOCHEMICAL COMPUTER CODE
FOR SPECIATION OF INORGANIC CHEMICALS)
Eh- OXYGEN-REDUCTION POTENTIAL
EPRX- ELECTRIC POWER RESEARCH INSTITUTE
EPA- U.S. ENVIRONMENTAL PROTECTION AGENCY
MINTEQ- A COMBINATION OP TWO EQUILIBRIUM aEOCHEMICAL
COMPUTER CODES (MINERAL EQUILIBRIUM CODE (MINTEQ) AND
SPECIATION CODE (WATEQ3) FOR SPECIATION OF INORGANIC
CHEMICALS)
MITE- MUNICIPAL INNOVATIVE TECHNOLOGY EVALUATION
MSW- MUNICIPAL SOLID WASTE
MWCA- MUNICIPAL WASTE COMBUSTION ASH
MWCAS- MUNICIPAL WASTE COMBUSTION ASH SUBCOMMITTEE
NTIS- NATIONAL TECHNICAL INFORMATION SERVICE
ORD- OFFICE OF RESEARCH AND DEVELOPMENT OF THE U.S. EPA
OSW- OFFICE OF SOLID WASTE OF THE U.S. EPA
pH- THE NEGATIVE LOG OF THE HYDROGEN ION CONCENTRATION
RREL- RISK REDUCTION ENGINEERING LABORATORY OF THE U.S. EPA
SAB- SCIENCE ADVISORY BOARD OF THE U.S. ENVIRONMENTAL
PROTECTION AGENCY
S/S- SOLIDIFICATION/STABILIZATION
TAP- TECHNICAL ADVISORY PANEL
TCLP- TOXICITY CHARACTERISTIC LEACHING PROCEDURE
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APPENDIX C - INITIAL REVIEW DOCUMENTS
Item It A copy of the Request for Participation that has been
sent to potential participants. This document describes the
S/S program, but concentrates on Phase I. This document also
includes tables of tests and analyses proposed for
characterizing and evaluating the untreated and treated
residues.
Item 2s A list of members of the Technical Advisory Panel
(TAP) which was established to assist in the selection of
tests and analyses to be used, evaluation of potential
processes for including in the program, evaluation of data and
similar aspects of the program. This panel was considered
necessary to have a program that is credible to state and
local authorities likely to implement potential processes, as
well as the public.
Item 3: A copy of cost estimates prepared for conducting Phase
I. This estimate was prepared by a small sub-group of the
TAP.
Item 4: Several items of information which provide background
on the generation of the program and previous activities,
These include a letter from Carlton c. Wiles to the TAP,a
letter from Carlton C. Wiles to John H. skinner dated Oct. 27,
1988 describing the S/S program, and a letter from wiles to
Skinner dated March 4, 1988 submitting a proposed plan for
the S/S program.
Item 5: A description of the Municipal Innovative Technology
Evaluation (MITE) program. The MWC Ash S/S program is now
being considered a MITE prototype.
Item 6: Some issues which will or may affect the conduct and
outcome of the program.
Item 7: A letter from Wiles to Kooyoomjian dated June 5, 1989
identifying other quest ions/issues on which MWCAS could focus.
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APPENDIX D - RESOURCE MATERIAL
1) ASME White Paper on Research Needs for Municipal Waste
Combustor Residue Management, 1988, 10 pages
2) ASTM, Standard Specification for Fly Ash and Raw or calcined
Natural Pozzolan for Use as a Mineral Admixture in Portland
Cement Concrete, Astm Designation G618-89, pages 296-298
3) ASTM, Standard Test Methods for Sampling and Testing Fly Ash
or Natural Pozsolans for Use as a Mineral Admixture in
Portland Cement Concrete, Astra Designation C311-88, pp. 185-
189
4) Battelle Pacific Northwest Laboratory, FASTCHEM™, Package,
Volume 4, User's Guide to the ECHEM Equilibrium Geochemistry
Code, 1PRI Report Number EA 5870-ccm, September 1988
5) Baumeister, T, ed., Standard Handbook for Mechanical
Engineers, McGraw-Hill Book Company, New York, 1978
6) Briefing by EPA's ORD Staff entitled "Municipal Waste
Combustion Ash solidification/stabilization Program"1
dated Sept. 18-19, 1989, 22 pages
7) Briefing by EPA's ORD Staff entitled "III Review of the
Municipal Waste Combustion Ash Solidification/Stabilization
Program Design," Sept, 18-19, 1989, 27 pages
8) Briefing by EPA's ORD Staff entitled, "IV. Key Issues and
Program Directives," Sept. 18-19, 1989, 18 pages
9) Briefing by EPA's ORD Staff, Three tables entitled (1)
Measured Concentrations of Metals in the Extract from EP Tox
Tests from Various Processes and Sites; (2) Ranges of Values
of Toxic Metals in MSW Combustion Ash? (3) Ranges of Values
of Tox Metals in MSW Combustion Ash, 3 pages
10) Cal Recovery Systems, Inc., North Santa Clara County
Comprehensive Waste Characterization Study (1982-82), Report
No. 83-10, January 1984
11) city of Los Angeles, Bureau of Sanitation, unpublished data,
1983
12) EPA Memo with attachments, Wiles, Carlton C, to Kooyoomjian,
K. Jack, entitled "Information for SAB Review of EPA MWC Ash
S/s Program," May 11, 1989
13) EPA Memo, Wiles, Carlton C. to Kooyoomjian, K. Jack entitled,
"SAB Review of EPA MWC Ash Solidification/stabilization
Program," June 5, 1989, 2 pages
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14) Felmy, A.R., D.C. Girvin and E,A. Jenne, MINTEQ: A Computer
Program for Calculating Aqueous Geocheraieal Equilibria, EPA
Report Number 600/3-84-032, 1984 (Also available from NTIS,
Springfield, VA as NTIS Report Number PB 84-157148),
15) Franklin Associates, characterization on Municipal Solid Waste
in the United States, 1960 to 2000, a report prepared for the
USEPA, Contract No. 68-01-7037, 1986
16) Franklin, M.A,, "Characterizing the Municipal Waste Stream,"
presented at the Third Annual Symposium on Materials and
Energy Recovery from Municipal Solid Waste, October 20-22,
1987
17) Franklin Associates, Characterization of Products Containing
Lead and Cadmium in Municipal Solid Waste in the United
States, 1970-2000. Executive Summary. EPA/53Q-SW-89~015c
18) Hartlen, Jan.Dr., Director General, Swedish Geotechnical
Institute, "Incinerator Ash Utilization In Some Countries In
Europe," pages 33-47, no date
19) H.R. 2162, 101st Congress, 1st Session, House of
Representatives Bill Dated May l, 198S, To amend Subtitle D
of the Solid Waste Disposal Act to regulate municipal solid
waste incinerators and municipal solid waste incinerator ash,
19 pages
20) Kaiser, E.R., D.C. Zeit, and J,B. MeCaffery, "Municipal
Incinerator Refuse and Residue." Proceedings of the 1968
National incinerator Conference, ASM!, May 1968
21) New York State Department of Environmental Conservation, Ash
Residue Characterization Project Report, July 1987
22) Savage, G.M. and J.c. Glaub, "Approaches to Coupling the
Design of Resource Recovery Facilities to Performance
Specifications and Acceptance Testing," Proceedings of the
llth National Waste Processing Conference, ASMS, Orlando,
Florida, June 1984
23) SAB Report of the Environmental Effects, Transport and Fate
Committee entitled "Evaluation of Scientific Issues Related
to Municipal Waste Combustion,1* SAB-EETFC-88-25, April 1988
24) SAB Report of the Environmental Engineering Committee
entitled, "Resolution on Use of Mathematical Models by EPA for
Regulatory Assessment and Decision-Making," EPA-SAB-EEC-89-
012, January 1989
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