Technical
Background
Document:
Mercury
Wastes
Evaluation
of
Treatment
of
Bulk
Elemental
Mercury
Final
Report
February
8,
2002
Submitted
to:

U.
S.
Environmental
Protection
Agency
Ariel
Rios
Building
Office
of
Solid
Waste
1200
Pennsylvania
Avenue,
N.
W.
Washington,
D.
C.
20460
Submitted
by:

Science
Applications
International
Corporation
Engineering
and
Environmental
Management
Group
11251
Roger
Bacon
Drive
Reston,
Virginia
20190
EPA
Contract
No.
68­
W­
98­
025
Work
Assignment
No.
3­
8
SAIC
Project
No.
06­
0758­
08­
1373­
000
Evaluation
of
Treatment
of
Bulk
Elemental
Mercury
Executive
Summary
The
Environmental
Protection
Agency
(
EPA)
and
Department
of
Energy
(
DOE)
have
collaborated
on
a
series
of
studies
to
evaluate
the
effectiveness
of
treatment
technologies
at
stabilizing
wastes
containing
large
concentrations
of
mercury.
In
addition
to
mercurycontaminated
wastes,
the
disposal
of
bulk
elemental
mercury
is
of
concern
because
of
the
excess
quantity
of
mercury
in
the
Defense
Logistics
Agency
(
DLA)
stockpile.

The
study
described
in
this
report
was
designed
to
assist
in
evaluation
of
options
for
disposition
of
the
inventory,
by
providing
information
on
the
ability
of
current
technologies
to
convert
elemental
mercury
(
or
wastes
with
large
components
of
elemental
mercury)
into
a
stable
waste
form
for
disposal.
The
study
evaluated
the
effectiveness
of
three
technologies
at
stabilization
of
bulk
elemental
mercury.
Bulk
elemental
mercury
was
treated
by
each
vendor,
and
the
treated
waste
forms
evaluated
for
mercury
leachability,
using
both
the
TCLP
and
a
novel,
automated,
constant­
pH
leaching
protocol.
Constant
pH
leaching
was
conducted
at
pH
2,
4,6,
8,
10,
and
12
for
14
days
at
each
pH.

The
report
provides
descriptions
of
the
study
plan
and
the
treatment
processes,
as
well
as
detailed
discussions
of
the
leaching
results.
The
leaching
data
presented
demonstrate
that
the
stability
of
the
mercury
in
the
treated
waste
forms
varies
widely
across
the
pH
range
tested.
Clearly,
the
stability
of
mercury
in
these
treated
waste
forms
will
be
highly
dependant
on
the
disposal
conditions.
The
combination
of
site­
specific
disposal
conditions
and
appropriate
treatment
technology
must
be
considered
as
decisions
are
made
about
disposal
of
waste
bulk
elemental
mercury.

Project
Team
Mary
Cunningham
 
Project
Manager
EPA
1201
Pennsylvania
Ave.,
NW
Washington,
DC
20460
John
Austin,
EPA
1201
Pennsylvania
Ave.,
NW
Washington,
DC
20460
Mike
Morris
ORNL­
UT­
Battelle
PO
Box
2008
Oak
Ridge,
TN
37831­
6180
Greg
Hulet,
INEEL­
Bechtel
PO
Box
1625
Idaho
Falls,
ID
83415­
3875
1.
Introduction
The
Hazardous
and
Solid
Waste
Amendments
(
HSWA)
to
the
Resource
Conservation
and
Recovery
Act
(
RCRA)
require
the
EPA
toestablish
treatment
standards
for
all
listed
and
characteristic
hazardous
wastes
destined
for
land
disposal.
After
the
effective
date
of
a
restriction,
wastes
that
do
not
meet
the
Land
Disposal
Restrictions
(
LDR)
treatment
standards
are
prohibited
from
land
disposal.

The
LDR
treatment
standards
for
the
six
waste
codes
(
D009,
K071,
K106,
P065,
P091,
and
U151)
which
contain
mercury
as
the
primary
hazardous
constituent
(
Mercury
Wastes)
were
promulgated
in
the
Third
Third
LDR
Rule
(
55
FR
22520,
June
1,
1990).
Some
of
these
standards
were
revised
when
EPA
promulgated
Universal
Treatment
Standards
in
the
Phase
II
LDR
Rule
(
59
FR
47980,
September
19,
1994).
Since
these
rules
were
promulgated,
however,
the
Agency
has
become
aware
of
information
and
data
which
indicate
that
the
treatment
standards
for
some
categories
of
these
wastes
may
be
inappropriate
and
warrant
further
review.

1.1
Disposal
Options
for
Wastes
Containing
>
260
mg/
kg
Total
Mercury
Under
the
existing
LDRs,
treatment
by
stabilization
and
disposal
is
not
an
available
option
for
most
wastes
containing
greater
than
260
mg/
kg
total
mercury
(
high
mercury
wastes).
The
reasons
given
in
the
3rd
3rd
rule
for
this
regulation
are
that,
"
EPA's
data
for
untreated
mercury
wastes
being
retorted/
roasted
domestically
show
minimum
concentrations
of
mercury
up
to
255
mg/
kg,"
and
that
"
There
is
a
strong
preference
in
the
land
disposal
restrictions
legislation
for
treatment
standards
to
be
based
on
recovery
where
possible."
The
technical
background
document
for
mercury
wastes
also
cited
data
from
attempts
to
treat
K106
sludge
containing
25.9
g/
kg
of
total
mercury
using
conventional
metal­
stabilizing
agents
(
cement,
kiln
dust,
lime/
fly
ash),
indicating
that
the
leachability
of
the
waste
was
actually
increased
by
the
process.

Mercury
is
a
high­
priority
chemical
at
EPA.
It
is
one
of
twelve
Persistent,
Bioaccumulative
and
Toxic
Chemicals
(
PBT)
targeted
in
the
U.
S.
Bi­
National
Strategy
between
the
U.
S.
and
Canada
and
is
included
in
EPA's
PBT
Strategy.
There
are
also
efforts
in
the
Agency
to
reduce
mercury
consumption
and
to
take
mercury
out
of
circulation
to
minimize
air
emissions.
For
these
reasons,
it
appears
that
the
general
preference
for
recovery
over
immobilization
may
not
be
appropriate
for
some
categories
of
mercury
wastes.
In
addition,
various
commenters
and
petitioners
have
submitted
data
indicating
that
wastes
containing
concentrations
well
above
260
mg/
kg
may
be
effectively
stabilized.
Therefore,
EPA
has
decided
to
revisit
the
issue
of
mercury
stabilization
by
gathering
currently
available
performance
data,
possibly
conducting
new
stabilization
research,
and
investigating
the
long­
term
potential
for
oxidation
or
vaporization
of
land
disposed
mercury.
1.2
Wastes
which
are
not
directly
amenable
to
roasting
and
retorting
Retorting
or
roasting
for
recovery
(
RMERC)
is
currently
required
for
inorganic
high
mercury
wastes.
Commenters
and
petitioners
have
asserted
that
many
subcategories
of
mercury
wastes
(
e.
g.,
inorganic
salts,
corrosive
wastes,
incineration
residues,
wastewater
treatment
residues)
are
not
directly
amenable
to
RMERC
treatment,
and
are
not
accepted
by
commercial
retorting
facilities.
Although
EPA's
general
position
has
been
that
those
nonamenable
subcategories
can
be
pretreated
to
make
recovery
possible,
current
management
practices
indicate
that
this
position
may
be
impractical
and
unrealistic.
Therefore,
EPA
has
decided
to
investigate
alternative
treatment
technologies
to
roasting
and
retorting
for
high­
mercury
wastes.

1.3
Incineration
of
Mercury
Wastes
Incineration
(
IMERC)
is
currently
either
required
or
allowed
as
an
alternative
to
RMERC
for
organic
high
mercury
wastes.
The
rationale
for
this
standard
given
in
the
3rd
3rd
rule
is
that
IMERC
will
destroy
the
organic
component
of
organo­
mercury
complexes
or
mixtures,
so
that
the
"
valuable
mercury"
present
in
the
waste
can
be
subsequently
recovered
from
the
incineration
residuals
(
e.
g.,
ash,
baghouse
dust,
sludge
from
treated
scrubber
water).
However,
given
the
high
volatility
of
mercury,
it
is
reasonable
to
assume
that
both
mercury
and
organo­
mercury
compounds
will
be
vaporized
by
incineration
rather
than
remain
in
the
ash.
Although
some
of
this
mercury
will
be
captured
by
air
pollution
controls,
the
rest
will
be
lost
to
the
atmosphere.
Furthermore,
evaluation
of
current
waste
management
practices
indicates
that
incineration
residuals
are
in
fact
not
being
treated
for
mercury
recovery.
Therefore,
the
Agency
has
decided
to
further
investigate
whether
treatment
alternatives
exist
for
mercury
wastes
that
might
currently
be
going
to
incinerators
for
treatment.

Elemental
Mercury
Waste
Project
Report
The
purpose
of
this
report
is
to
provide
an
evaluation
of
the
effectiveness
of
commercially
available
stabilization
technologies
on
elemental
mercury.
The
Department
of
Defense
has
maintained
a
huge
inventory
of
mercury
for
many
years.
However,
the
DoD
has
determined
that
they
will
not
need
the
volumes
in
the
inventory.
The
DoD
is
preparing
an
environmental
impact
analysis
of
the
options
for
disposition
of
the
inventory.
The
options
include
sale,
storage
by
other
governmental
agencies,
and
disposal.
This
report
is
designed
to
assist
in
identifying
the
proper
methods
of
safe
1
40
CFR
268.40
2
This
procedure
is
described
in
Method
1311
of
U.
S.
Environmental
Protection
Agency
(
EPA)
Publication
SW­
846.
2.
Background
The
Resource
Conservation
and
Recovery
Act
(
RCRA)
1
defines
several
categories
of
mercury
wastes,
each
of
which
has
a
defined
technology
or
concentration­
based
treatment
standard,
or
universal
treatment
standard
(
UTS).
RCRA
defines
mercury
hazardous
wastes
as
any
waste
that
has
a
TCLP
value
for
mercury
of
0.2
mg/
L
or
greater.
Three
of
these
categories,
all
nonwastewaters,
fall
within
the
scope
of
this
report
on
new
technologies
to
treat
mercurycontaminated
wastes:

­
Wastes
as
elemental
mercury;
­
Hazardous
wastes
with
less
than
260
mg/
kg
[
parts
per
million
(
ppm)]
mercury;
and
­
Hazardous
wastes
with
260
ppm
or
more
of
mercury.

2.1
Current
Treatment
Methods
While
this
report
deals
specifically
with
the
first
category
 
waste
elemental
mercury
 
the
other
two
categories
will
be
discussed
briefly
so
that
the
full
range
of
mercury
treatment
challenges
can
be
understood.
The
current
treatment
requirements
for
these
three
categories
are
as
follows:

­
Waste
as
elemental
mercury
 
RCRA
identifies
amalgamation
(
AMLGM)
as
the
treatment
standard
for
elemental
mercury
contaminated
with
radioactive
materials.

­
Waste
with
<
260
ppm
mercury
 
No
specific
treatment
method
is
specified
for
hazardous
wastes
containing
<
260
ppm.
However,
RCRA
regulations
require
that
such
wastes
that
exceed
a
TCLP
mercury
concentration
of
0.20
mg/
L
be
treated
by
a
suitable
method
to
meet
the
toxicity
characteristic
leaching
procedure
(
TCLP)
2
limit
for
mercury
of
0.20
mg/
L.

­
Waste
with
>
260
ppm
mercury
 
For
hazardous
wastes
with
mercury
contaminant
concentrations
>
260
ppm
and
RCRA­
regulated
organic
contaminants
(
other
than
incinerator
residues),
incineration
or
retorting
(
IMERC
or
RMERC)
is
the
treatment
standard.
For
wastes
with
mercury
contaminant
concentrations
>
260
ppm
that
are
inorganic,
including
incinerator
and
retort
residues,
RMERC
is
the
treatment
standard.

EPA's
hazardous
waste
classification
system
identifies
six
categories
of
mercury­
bearing
wastes,
each
of
which
has
a
separate
RCRA
waste
code.
Table
2­
1
shows
the
six
mercury
waste
codes
and
a
brief
description
adapted
from
the
May
28,
1999
proposed
rule:
Table
2­
1
RCRA
Codes
for
Wastes
that
Contain
Mercury
Waste
Code
Description
D009
 
Characteristic
Mercury
Wastes
D009
wastes
are
extremely
variable
in
composition,
and
depend
on
the
industry
and
process
that
generate
the
waste.
Some
of
the
more
common
types
of
D009
wastes
include
miscellaneous
wastes
from
chlor­
alkali
production
facilities
(
especially
cell
room
trench
sludge
and
activated
carbon
for
liquid
or
gas
purification),
used
fluorescent
lamps,
batteries,
switches,
and
thermometers.
D009
wastes
are
also
generated
in
the
production
of
organomercury
compounds
for
fungicide/
bactericide
and
pharmaceutical
uses,
and
during
organic
chemicals
manufacturing
where
mercuric
chloride
catalyst
is
used.*

K071
 
Brine
purification
muds
from
the
mercury
cell
process
in
chlorine
production,
where
separately
prepurified
brine
is
not
used
K071
wastes
are
generated
by
the
chlor­
alkali
industry
in
the
mercury
cell
process.
In
this
process,
sodium
chloride
is
dissolved
to
form
a
saturated
brine
solution.
The
brine
solution
is
purified
by
precipitation,
using
hydroxides,
carbonates,
or
sulfates.
The
precipitate
is
dewatered
to
form
K071
wastes,
while
the
purified
brine
continues
in
the
process.
The
depleted
solution
from
the
mercury
cell
is
ultimately
recycled
to
the
initial
step
of
the
process.

K106
 
Wastewater
treatment
sludge
from
the
mercury
cell
process
in
chlorine
production
Like
K071
wastes,
K106
wastes
are
generated
from
chlorine
production
using
the
mercury
cell
process.
Effluent
from
the
mercury
cell
includes
spent
brine,
a
portion
of
which
is
recycled
and
a
portion
of
which
is
purged
to
wastewater
treatment.
Other
plant
area
wastewaters
(
e.
g.,
stormwater,
washdown
waters)
are
also
typically
sent
to
this
treatment
system.
The
wastewater
treatment
process
generates
a
sludge
through
precipitation
and
filtering,
which
is
K106
waste.
The
mercury
concentration
in
K106
waste
is
consistently
greater
than
260
mg/
kg
and
therefore
retorting
is
a
required
technology
for
this
waste.

P065
 
Mercury
fulminate
P065
wastes
consist
of
discarded
mercury
fulminate
product,
off­
specification
mercury
fulminate
product,
and
container
or
spill
residues
thereof.

P092
 
Phenylmercury
acetate
P092
wastes
consist
of
discarded
phenylmercury
acetate
product,
off­
specification
phenylmercury
acetate
product,
and
container
or
spill
residues
thereof.

U151
 
Mercury
U151
wastes
consist
of
discarded
elemental
mercury
product,
off­
specification
metallic
mercury
product,
and
container
or
spill
residues
thereof.
The
principal
constituent
of
U151
is
metallic
mercury.**

*
U.
S.
EPA,
Best
Demonstrated
Available
Technology
(
BDAT)
Background
Document
for
Mercury
Wastes,
Nov
1989,
page
2­
18.
**
Mercury
Treatment
and
Storage
Options
Summary
Report,
A.
T.
Kearney
report
for
USEPA
Reg
5,
May
1997,
page
1.

2.2
What
is
the
Impetus
for
the
Current
Study?

2.2.1
Land
Disposal
Restrictions
The
Land
Disposal
Restrictions
(
LDR)
treatment
standards
established
by
the
3rd
3rd
Rule
(
55
FR
2250,
June
1,
1990)
requires
roasting
and
retorting
(
RMERC)
to
recovery
mercury
as
the
treatment
for
high­
mercury
wastes
greater
than
260
mg/
kg
mercury.
In
the
3rd
3rd
Final
Rule,
EPA
cited
Congress'
preference
for
"
treatment
standards
to
be
based
on
recovery,
where
possible"
(
S.
Rpt.
98­
284,
p.
17).
In
addition,
the
Agency
cited
technical
reasons
for
not
3
Memorandum,
G.
Tracy
Mehan,
III
to
Steve
Johnson,
September
27,
2001,
"
Developing
an
EPA
Game
Plan
for
Surplus
Mercury
(
draft
issue
paper).
promulgating
stabilization
as
the
preferred
treatment
technology
for
high
mercury
subcategory
wastes.
Specifically,
data
available
to
support
the
3rd
3rd
Final
Rule
indicated
that
the
metal
stabilization
agents
actually
increased
the
mobility
of
mercury
in
the
stabilized
matrix.
Given
a
growing
excess
of
mercury
stocks,
as
uses
of
mercury
decline,
the
disposal
requirements
for
excess
mercury
need
to
be
considered.

2.2.2
Defense
Logistics
Agency
Stockpile
The
National
Defense
Stockpile
program
was
established
by
Congress
in
the
Strategic
and
Critical
Materials
Stock
Piling
Act
of
1939,
as
amended,
to
minimize
the
United
States'
dependence
on
foreign
sources
of
essential
materials
in
times
of
national
emergency.
Between
1949
and
1988,
the
General
Service
Administration
and
Federal
Emergency
Management
Agency
were
responsible
for
the
program.
In
1988,
the
responsibility
for
the
program
was
delegated
to
the
Secretary
of
Defense
who
assigned
the
program
to
the
Defense
Logistics
Agency
(
DLA)
.
The
Defense
National
Stockpile
Center
(
DNSC)
was
established
within
DLA
to
manage
the
program.
DNSC
is
headquartered
at
Fort
Belvoir,
Virginia
and
operates
storage
depots
nationwide.
The
stockpile
currently
includes
68
commodities,
including
mercury.

DNSC
is
responsible
for
all
activities
necessary
to
provide
safe,
secure,
environmentally
sound
stewardship
of
all
commodities
in
the
National
Defense
Stockpile.
Over
the
past
several
years
as
new
technologies
have
evolved
and
global
economies
emerged,
Congress
has
declared
most
of
the
Defense
National
Stockpile
materials
to
be
in
excess
of
national
defense
needs
and
has
authorized
their
disposition,
generally
by
sale.
Mercury
is
one
of
these
commodities
determined
to
be
in
excess
of
national
defense
needs.
In
January
2001,
DNSC
initiated
an
Environmental
Impact
Statement
(
EIS)
to
solicit
comments
from
the
public
and
policy­
makers
about
what
to
do
with
its
remaining
11
million
pounds
of
mercury.
3
The
DNSC
excess
inventory
of
mercury
is
"
prime
virgin"
i.
e.,
between
99.5
and
99.9
percent
pure
mercury.
The
material
is
currently
stored
in
steel
flasks
weighing
about
76
pounds
(
34.5
kilograms).
The
flasks
are
stored
in
wooden
pallet
boxes.
Some
of
the
flasks
date
from
the
1940s
and
1950s.

As
custodian
of
the
excess
inventory
of
mercury,
DNSC
must
decide
on
a
strategy
for
management
of
the
material.
As
required
by
CEQ
and
DLA
NEPA
regulations,
this
decision
must
include
consideration
of
a
range
of
reasonable
management
alternatives
and
the
environmental
impacts
of
those
alternatives.
2.3
Bulk
Elemental
Mercury
Treatment
Study
The
Bulk
Elemental
Mercury
Treatment
study
was
conducted
to
analyze
the
effectiveness
of
commercially
available
technologies
for
stabilizing
elemental
mercury.
This
study
was
sponsored
by
EPA
and
focuses
on
the
DLA
stockpiles.
The
study
started
with
a
solicitation
to
industry
to
demonstrate
the
effectiveness
of
their
stabilization
process
treatment
of
elemental
mercury.
This
effort
had
two
major
objectives.

1.
The
first
objective
was
to
evaluate
alternative
processes
to
RMERC
and
IMERC
for
the
DLA
elemental
mercury
stores.
To
that
end,
a
process
that
will
treat
an
elemental
mercury
sample
to
meet
a
TCLP
treatment
goal
of
0.025
mg/
L
or
less
was
desired.

2.
The
second
objective
was
to
provide
EPA
with
the
treated
waste
forms
for
use
in
empirical
testing
to
compare
proposed
new
analytical
protocols
to
the
standard
TCLP
results,
and
to
assess
potential
suitable
disposal
environments
for
the
wastes
forms.

Technology
vendors
participated
in
this
demonstration
at
their
expense,
except
for
the
analytical
costs
incurred
from
the
use
of
an
outside
laboratory
to
perform
the
surrogate
waste
characterization,
TCLP
testing
on
the
treated
waste
forms,
and
the
costs
of
shipping
the
treated
waste
forms
to
ALTER,
Inc.,
where
the
constant­
pH
leaching
was
performed.

Sample
waste
forms
from
stabilization
of
elemental
mercury
were
characterized
and
leached
by
ALTER,
Inc.,
using
both
the
TCLP
and
a
novel,
automated,
constant­
pH
leaching
protocol.
These
data
are
presented
in
detail
in
Section
5.
Characterization
of
the
waste
forms
consisted
of
bulk
density,
moisture
content,
percent
organic
matter,
cation
exchange
capacity
and
particle
size
distribution.
These
data
are
presented
in
Appendix
C.
Mercury
vapor
pressure
testing
will
also
be
performed
on
the
final
treated
waste.
The
results
of
the
Oak
Ridge
National
Laboratory
testing
will
be
presented
in
a
separate
report.
3.
Detailed
Description
of
Study
3.1
Overall
Plan
Mercury
contamination
exists
in
various
forms,
such
as
soil,
sludges,
and
debris,
and
in
various
species,
such
as
organic,
inorganic,
and
elemental.
The
objective
of
this
investigation
is
to
provide
information
on
the
ability
of
current
technologies
to
convert
elemental
mercury
(
or
wastes
with
large
components
of
elemental
mercury)
into
a
stable
waste
form
for
disposal.
Each
of
the
current
technologies
relies
on
chemical
reactions
to
minimize
volatilization
and
solubility,
as
opposed
to
recovery
or
separation
technologies
which
generate
a
near
mercury­
free
residual
in
addition
to
concentrated
or
purified
mercury.

EPA
and
DOE
are
investigating
possible
stabilization
methods
for
mercury­
contaminated
waste
and
mixed
waste
streams.
These
methods
are
`
nonthermal,'
occurring
at
conditions
below
the
boiling
point
of
mercury
(
about
350
E
C
or
650
E
F).
To
investigate
the
ability
of
these
technologies
to
effectively
treat
wastes,
EPA
designed
a
detailed
project
plan
(
EPA
Quality
Assurance
Project
Plan
 
Technical
Support
for
Amendment
of
Land
Disposal
Restrictions
for
Mercury
Wastes,
December
2000,
Appendix
A).
EPA
requested
that
several
different
vendors
attempt
to
treat
elemental
mercury
using
their
processes
identified
for
the
MER
04
project.
The
resulting
treated
wastes
would
each
undergo
a
rigorous
set
of
procedures
to
better
understand
the
performance
of
the
technology.
In
addition
to
reducing
mercury
mobility,
the
process
should
minimize
worker
exposure,
minimize
volume
increase
as
waste
is
treated,
minimize
secondary
waste
generation,
and
maximize
operational
flexibility.

In
completing
this
project,
a
coordinated
effort
was
required
between
technology
vendors,
laboratories,
DOE/
ORNL,
and
EPA.
Key
participants
in
the
project
were
as
follows:

Treatment
technology
vendors
 
Three
vendors
volunteered
to
be
participants
in
the
study.
These
vendors
participated
in
the
related
MER
04
surrogate
waste
study.
Detailed
discussion
of
their
roles,
technologies,
and
activities
are
discussed
in
Chapter
4
of
this
report.
Responsibilities
of
the
vendors
included
treating
the
elemental
mercury
using
bench
scale
technology,
and
sending
the
treated
waste
back
to
the
laboratory.

The
Accelerated
Life
Testing
and
Environmental
Research
Corporation
(
ALTER),
Dillsboro,
IN
 
ALTER's
responsibilities
include
providing
instructions
to
the
vendors,
receiving
the
treated
wastes,
and
conducting
leaching
tests
of
the
resulting
treated
wastes.
Actual
analysis
of
the
treated
waste
material
or
leachates
for
most
chemical
and
physical
parameters
(
including
mercury)
was
conducted
by
other
laboratories.
ALTER
conducted
alkalinity
and
acidity
testing,
and
pH
analysis.

Environmental
Enterprises,
Cincinnati,
OH
 
Environmental
Enterprise
was
primarily
responsible
for
conducting
mercury
analysis
of
solid
and
aqueous
(
i.
e.,
leachate)
matrices
(
Appendices
B
and
E).

Agvise
Laboratories,
Northwood,
ND
 
Agvise
was
primarily
responsible
for
testing
physical
characteristics
of
the
treated
waste.
These
tests
include
bulk
density,
moisture
content,
percent
organic
matter,
cation
exchange
capacity,
and
particle
size
distribution
(
Appendix
C).
The
Agvise
testing
uses
standard
methods
for
soils,
established
by
the
USDA
and
the
Soil
Society
of
America
(
Appendix
D).

Oak
Ridge
National
Laboratory,
Oak
Ridge,
TN
 
ORNL
is
responsible
for
the
measurement
of
the
mercury
vapor
pressure
at
20
E
C
and
60
E
C
of
treated
waste
forms.
ORNL
results
will
be
reported
separately.

Activities
performed
by
these
parties
are
described
below
in
more
detail.
These
activities
include
preparing
a
surrogate
sludge
for
evaluation
and
treatment
and
characterizing
both
the
untreated
surrogate
sludge
and
treated
residue.
Activities
relating
to
the
treatment
itself
are
discussed
in
detail
in
Section
4
of
this
report.

3.1.1
Elemental
Mercury
Preparation
Each
vendor
was
responsible
for
obtaining
elemental
mercury
for
use
in
the
study.
Relatively
small
quantities
(
less
than
approximately
one
kilogram
per
batch)
were
generally
used
by
the
vendors.

3.1.2
Treated
Waste
Characterization
The
commercial
vendors
returned
the
treated
material
to
ALTER
for
testing.
The
vendortreated
materials
were
characterized
and
subjected
to
physical
and
chemical
analyses
to
determine
their
behavior
under
a
range
of
potential
disposal
conditions.

3.2
Physical
and
Chemical
Analysis
Samples
of
the
baseline
(
elemental)
mercury
and
the
treated
waste
generated
by
the
vendors
were
subjected
to
a
battery
of
physical
and
chemical
analyses.
The
technologies
used
by
the
vendors
are
described
in
Section
4.
Table
3­
1
summarizes
the
analyses
conducted
on
the
materials.
These
testing
and
analysis
procedures
are
described
below:

Baseline
untreated
mercury:
total
mercury,
TCLP
mercury,
and
constant
pH
leaching
analysis
of
mercury;
physical
and
chemical
analysis
at
Agvise
Laboratory,
additional
characterization
by
ALTER.

Treated
waste:
total
mercury,
TCLP
mercury,
and
constant
pH
leaching
analysis
of
mercury;
physical
and
chemical
analysis
at
Agvise
Laboratory,
additional
characterization
by
ALTER.

In
order
to
assess
the
stability
of
the
materials,
several
leaching
procedures
were
performed
on
the
baseline
untreated
and
vendor
treated
waste.
Leaching
tests
performed
by
ALTER
included
the
toxicity
characteristic
leaching
procedure
(
TCLP)
and
constant
pH
testing.
Upon
completion
of
each
leaching
test,
the
pH
of
the
leachate
was
recorded
and
leachate
samples
sent
to
Environmental
Enterprises
Inc
for
determination
of
their
mercury
content.
These
two
leaching
tests
are
discussed
below:

Toxicity
Characteristic
Leaching
Procedure
 
This
is
a
standard
regulatory
test
(
40
CFR
261.24,
SW­
846
Method
1311)
intended
to
determine
the
potential
mobility
of
contaminants
in
a
solid
waste
under
simulated
landfill
conditions.
The
TCLP
entails
exposure
of
a
sample
that
has
been
size
reduced
to
pass
a
9.5
mm
sieve
to
a
20
fold
large
volume
of
acetate
buffer
for
18
hours.

Constant
pH
Leaching
 
Constant
pH
leaching
tests
are
a
means
to
determine
the
effect
of
pH
on
the
stability
of
a
waste.
The
constant
pH
procedure
was
developed
at
ALTER
and
is
attached
as
Appendix
B
to
the
QAPP
(
presented
as
Appendix
A
to
this
report).
Samples
are
leached
in
a
constant
pH
solution
that
is
adjusted
to,
and
maintained
at,
the
desired
pH
end
point.
The
constant
pH
leaching
tests
were
performed
at
a
minimum
of
pH
values
of
2,
4,
6,
8,
10
and
12.
The
pH
is
maintained
by
automated
systems
for
a
14
day
period,
at
which
point
the
resulting
leachate
is
filtered
and
analyzed
for
mercury.
A
nominal
20:
1
liquid/
solid
ratio
(
20
Kg/
1
L)
was
used
in
these
tests.
The
longer
exposure
period
of
14
days
was
selected
to
ensure
equilibrium
conditions
were
obtained.

Table
3­
1
Test
Procedures
for
Bulk
Elemental
Mercury
Project
Parameter
Reference
Laboratory
Matrices
Physical
characteristics:
density;
water
content;
particle
size;
cation
ion
exchange
capacity;
percent
organic
matter;
cations
(
magnesium,
potassium,
calcium,
sodium)
Standard
Methods
for
Soils
established
by
the
USDA
and
the
Soil
Society
of
America.
Agvise
Laboratories
1,
2
Mercury
analysis,
in
leachate
and
solid
matrices
SW
846
Method
7470A
Environmental
Enterprises
1,
2;
all
leachates
Mercury
vapor
pressure
testing
Jerome
431
Arizona
Instruments
(
Phoenix,
AZ)
ORNL
2
Alkalinity,
acidity
Standard
Methods
for
the
Examination
of
Water
and
Wastewater
ALTER
2
pH
Standard
Methods
for
the
Examination
of
Water
and
Wastewater
ALTER
All
leachates
Moisture
content,
particle
size
ASTM
ALTER
2
TCLP
leaching
SW
846
Method
1311
ALTER
1,
2
Constant
pH
leaching
 
ALTER
2
Matrices:
1:
elemental
mercury
(
untreated).
2:
treated
waste
prepared
by
each
vendor.
*
Only
total
levels
of
mercury
were
to
be
analyzed
in
the
untreated
waste
prepared
by
each
vendor.
4.
Treatment
Technologies
Four
waste
treatment
technology
vendors
participated
in
the
related
MER
04
study.
Three
of
these
vendors
(
identified
in
this
report
as
Vendors
A,
B
and
C)
elected
to
participate
in
the
elemental
study.
Each
of
the
technologies
used
by
the
three
vendors
involves
stabilization
and/
or
amalgamation
of
the
mercury.
ORNL
and
EPA
specifically
were
evaluating
technologies
which
immobilize,
rather
than
separate,
mercury
within
wastes.
Data
and
information
concerning
these
treatment
technologies
were
obtained
from
the
vendor
project
reports
submitted
to
EPA/
ORNL,
as
well
as
previously
prepared
technology
or
performance
descriptions
prepared
for
ORNL.

Detailed
descriptions
of
these
technologies
are
presented
in
this
section
of
the
report.
Similarities
and
differences
between
the
technologies
are
presented
in
Table
4­
1.

Table
4­
1
Summary
of
Technologies
Used
for
Treatment
of
Bulk
Elemental
Mercury
Comparison
Factor
Vendor
A
B
C
Process
Overview
Formation
of
mercuric
sulfide
followed
by
thermoplastic
encapsulation
using
sulfur
polymer
stabilization/
solidification
process
Formation
of
mercuric
sulfide
with
micro­
and
macroencapsulation
Amalgamation
and
stabilization
process
with
precipitation
of
stable
salt
Reagents
added
95%
sulfur
polymer,
5%
organic
modifier,
and
proprietary
additives
Sulfide
and
proprietary
encapsulants
Amalgamation
agent
and
proprietary
stabilization
reagent
Waste
Loading
(
On
dry
basis)
33
wt%
Phase
I:
55
wt%
Phase
II:
44
wt%
20.1
wt%

Volume
or
Weight
Increase
203%
by
weight
1500%
by
volume
Phase
I:
81.8%
by
weight
Phase
II:
127%
by
weight
398%
by
weight
Final
Form
of
Treated
Waste
Monolithic
solid
Soil­
like
and
macroencapsulated
pellets
Monolithic
Mercury
Losses
to
Air
Estimated
0.3%
None
identified
None
measured
or
expected
*
Several
vendors
use
reagents
and/
or
process
steps
which
have
been
claimed
to
be
confidential
business
information
(
CBI).
Only
non­
CBI
is
presented
in
this
report.

4.1
Vendor
A
Vendor
A
used
its
proprietary
sulfur
polymer
stabilization/
solidification
(
SPSS)
process
for
treating
the
elemental
mercury.
The
purpose
of
this
process
is
to
chemically
stabilize
and
physically
encapsulate
mercury
to
reduce
vapor
pressure
and
leachability.
This
process
is
conducted
in
two
stages.
The
first
step
is
a
reaction
between
elemental
mercury
and
powdered
sulfur
polymer
cement
to
generate
mercuric
sulfide
(
HgS).
(
Sulfur
polymer
cement
consists
of
95
wt­%
elemental
sulfur
reacted
with
five
wt­%
of
an
organic
modifier.)
During
reaction,
the
vessel
is
placed
under
inert
nitrogen
gas
to
prevent
mercuric
oxide
(
HgO)
formation
(
a
compound
much
more
environmentally
mobile
than
mercuric
sulfide)
and
heated
to
40
E
C
to
enhance
the
sulfide
formation.
The
purpose
of
this
first
step
is
to
chemically
stabilize
the
mercury.

The
purpose
of
the
second
step
is
to
solidify
the
product.
The
mixture
is
heated
to
130
E
C
to
melt
the
thermoplastic
sulfur
binder.
It
is
then
poured
into
a
mold.
On
cooling,
the
reacted
sulfide
particles
become
microencapsulated
within
the
monolithic
sulfur
matrix.

Pilot­
scale
SPSS
processing
was
accomplished
using
a
1­
ft3,
oil­
heated,
vertical
cone
mixer.
Mixing
action
was
provided
by
a
24­
inch
long
auger
screw.
Feed
materials
were
charged
to
the
unit
through
a
6­
inch
diameter
port
on
the
cone
lid
with
the
auger
screw
drawing
material
upward
from
the
base
of
the
cone.
When
mixing,
the
system
was
purged
with
an
inert
gas
by
connection
to
a
regulated
nitrogen
gas
supply.
Heat
was
provided
to
the
jacketed
cone
by
a
circulating
fluid
heat
transfer
system.
A
heated
ball
valve
at
the
base
of
the
cone
was
used
to
discharge
the
molten
SPSS
product.

Off­
gas
was
controlled
by
a
sequence
of
a
heat
exchanger,
a
liquid
nitrogen
trap,
and
HEPA/
charcoal
filters
prior
to
atmospheric
discharge.
Vendor
A
did
not
measure
mercury
air
releases
during
processing
of
the
elemental
mercury.
In
earlier
demonstrations
of
treatment
of
elemental
mercury
and
mercury­
contaminated
soils,
a
mercury
balance
demonstrated
that
0.3%
of
mercury
was
volatilized
and
captured
in
the
off­
gas
collection
system.

Vendor
A
submitted
two
physical
forms
of
treated
waste
(
both
from
batch
2)
to
ALTER
for
testing.
The
first
waste
form
was
created
by
allowing
the
molten
material
to
solidify
in
bulk.
The
second
waste
form
submitted
for
testing
by
vendor
A
was
pelletized.
To
prepare
the
pellets,
monolithic
material
was
heated
to
approximately
140
E
C
and
poured
into
Teflon
molds
to
create
small
pellets
approximately
8­
mm
in
diameter
by
8­
mm
in
length.
This
dimension
was
selected
so
that
the
material
would
meet
the
9.5
mm
particle
size
requirement
for
TCLP
testing.
The
bulk
(
monolithic)
material
was
crushed
at
ALTER,
using
a
commercial
compression
machine
to
yield
<
9.5mm
pieces
for
parallel
TCLP
testing.
Both
the
pellet
and
crushed
forms
were
tested
in
parallel
throughout
the
evaluation.

4.2
Vendor
B
Vendor
B
used
a
multi­
step
process
that
can
be
stopped
at
a
given
stage
dependent
on
what
the
performance
specification
is.
The
first
step
(
primary
stabilization)
consists
of
conversion
of
elemental
mercury
to
mercuric
sulfide
(
meta­
cinnabar).
This
step
fits
the
EPA
definition
of
elemental
mercury
amalgamation.
The
primary
product
is
then
subjected
to
micro
and
macro
encapsulation
utilizing
a
range
of
polymeric
and
other
agents
to
attain
the
desired
product
specification.
For
the
study
in
question
the
final
product
was
a
bead­
like
material
that
had
a
top
size
diameter
of
9.5
mm.

On
a
dry
weight
basis
the
primary
product
contained
55
wt­%
elemental
mercury.
The
product
that
has
been
processed
through
micro
and
macro
encapsulation
contained
44
wt­%
elemental
mercury
on
a
dry
weight
basis.

4.3
Vendor
C
Vendor
C
used
an
ambient
temperature
process,
developed
to
treat
elemental,
ionic,
and
complexed
forms
of
mercury
in
mixed
(
radioactive
and
hazardous)
waste.
Vendor
C
has
previously
permitted
and
operated
this
process
for
treatment
of
mercury­
contaminated
mixed
wastes.

Vendor
C
placed
approximately
1.5
to
2
kg
of
elemental
mercury
and
reagents
inside
of
a
sealed
polypropylene
bottle.
The
material
was
mixed
externally
(
i.
e.,
without
a
stirrer,
propeller,
or
other
internal
mechanism).
Following
treatment
of
the
elemental
mercury,
each
batch
remained
in
the
chamber.
The
final
waste
form
was
best
described
as
a
monolith
which
set
up
within
24
hours.
The
weight
of
the
treated
mercury
was
increased
significantly:
for
an
initial
1.5
to
2
kg
mercury,
the
final
weight
was
10
kg.
This
is
much
greater
than
the
15
to
20
%
increase
typically
seen
for
soil
treated
by
the
process.

Airborne
mercury
concentrations
were
not
obtained
during
this
study.
Releases
are
expected
to
be
minimal
because
all
steps
following
charging
of
the
mercury
and
reagents
(
e.
g.,
mixing,
setting)
are
conducted
within
the
sealed
bottle.
5.
Leaching
Results
Samples
of
the
treated
waste
form
from
each
vendor
were
leached
according
to
both
the
TCLP
and
the
constant
pH
leaching
protocol,
and
the
concentrations
of
mercury
in
both
the
waste
forms
and
leachate
were
measured.

Sections
5.1
to
5.3
present
the
leaching
data,
by
vendor,
both
as
a
concentration
of
mercury
in
the
leachate,
and
as
the
percentage
of
mercury
that
leached
from
the
treated
waste
form.
The
percent
mercury
calculations
are
based
on
the
waste
loading
data
provided
by
the
technology
vendors,
rather
than
on
the
measured
concentrations
of
mercury
in
the
waste
due
to
incomplete
digestion
of
the
diverse
final
waste
forms.
This
approach
was
used
because
the
data
indicate
a
significant
negative
bias
in
the
analysis
of
the
mercury
content
of
the
treated
waste
forms.
Quality
control
data
indicate
that
the
precision
and
bias
of
the
analysis
of
mercury
in
the
leachates
were
acceptable.

5.1
Vendor
A
Two
final
waste
forms
(
pellets
and
crushed
material)
were
evaluated.
Table
5­
1
summarizes
results
for
total
mercury
recovered
from
the
digested
solids
representing
the
treated
waste
form
and
the
TCLP
tests.
The
crushed
fraction
shows
more
uniform
leaching
results
(
i.
e.,
a
relatively
lower
standard
deviation
and
CV),
as
expected
for
a
sample
with
smaller
particle
size.
Also,
the
pelletized
waste
is
known
to
be
more
heterogeneous
than
the
monolith,
from
which
the
crushed
material
came.
However,
pellet
sample
3
is
the
only
solid
that
met
the
performance
goal
of
0.025
mg/
L
Hg
in
leachates
generated
using
the
TCLP.
One
replicate
of
each
waste
form
leached
unacceptably
in
excess
of
0.2
mg/
L
TCLP.

Table
5­
1
Analytical
Results
for
Vendor
A
EEI
Work
Order
01­
07­
213
TCLP
Pellets
Crushed
Sample
pH
TCLP
(
mg/
L)
Percent
Leached
Sample
pH
TCLP
(
mg/
L)
Percent
Leached
1
5.18
0.0580
0.0004
1
4.98
0.144
0.0009
2
5.22
1.13
0.0068
2
4.97
0.0493
0.0003
3
5.22
0.0243
0.0001
3
4.98
0.202
0.0012
Average
0.404
0.0024
Average
0.132
0.0008
Std.
Dev.
0.629
­
Std.
Dev.
0.0771
­
CV
155
­
CV
58.4
­
The
amount
of
mercury
recovered
by
the
TCLP
test
is
reported
as
percent
leached,
and
is
based
on
the
waste
loading
in
the
solid
sample.
Percent
leached
is
calculated
as
follows:

[(
mg
Hg/
L
leachate)/(
mg
Hg/
kg
sample/
20]
*
100
where
mg
Hg/
L
is
the
TCLP
result,
mg
Hg/
kg
sample
is
the
mercury
concentration
in
the
solid,
based
on
the
vendor's
waste
loading,
and
20
is
the
liquid
/
solid
ratio
of
the
leaching
test.

Results
for
the
constant
pH
leach
tests
are
tabulated
in
Table
5­
2
and
plotted
on
Figure
5­
1
with
the
TCLP
results.
For
this
waste
form,
the
constant
pH
results
at
pH
4
and
6
are
similar
to
the
TCLP
results
obtained
at
pH
~
4.98.

Table
5­
2
Constant
pH
Leaching
Results
for
Vendor
A
EEI
Work
Order
01­
07­
213
&
01­
10­
360
pH
Pellets
Crushed
RPD
Sample
Dups.
Hg
conc.
(
mg/
L)
Percent
Leached1
Leachate
volume2
(
mL)
Hg
conc.
(
mg/
L)
Percent
Leached1
Leachate
volu
me2
(
mL)

2
0.00542
0.000034
511.59
0.00658
0.00004
512.69
P
 
86.6
2
0.0137
0.000091
546.80
0.0132
0.00008
509.88
C
 
66.9
4
0.984
0.006136
514.48
0.0621
0.00042
552.00
­

6
0.0835
0.000511
504.43
16.7
0.11135
550.06
­

8
44.9
0.274293
503.99
30.8
0.22007
589.46
P
 
59.5
8
24.3
0.148242
503.29
53.5
0.36116
556.93
C
 
53.9
9
13.7
0.085078
512.33
­
­
­

10
0.0742
0.000499
555.21
0.0839
0.00054
531.59
­

11
0.00951
0.000063
550.01
­
­
P
 
60.2
11
0.0177
0.000121
561.98
­
­
C
­
NA
12
127
0.773669
502.58
74.6
0.53159
587.88
P
 
19.9
12
155
1.031492
549.02
23.5
0.20415
716.68
C
­
104
2
<
0.00050
­
501.81
<
0.00050
­
506.14
Blank
1
Calculated
based
on
the
waste
loading
in
the
solids.
2
Total
volume
of
leachate,
including
addition
of
NaOH
and/
or
HNO
3
0
.
0
0
1
0
.
0
1
0
.
1
1
1
0
1
0
0
1
0
0
0
0
2
4
6
8
1
0
1
2
1
4
pH
Hg
Conc.
(
mg/
L)
P
e
lle
t
s
Cru
s
h
e
d
0.025
mg
/
L
0.2
m
g
/
L
TCL
P
P
e
lle
t
s
TCL
P
C
ru
s
h
e
d
Figure
5­
1
Constant
pH
Leaching
Results
for
Vendor
A
Concentration
Leached
Table
5­
2
reports
the
analytical
results,
the
amount
of
mercury
leached
from
the
solid
(
percent
leached),
and
the
total
volume
of
leachate
fluid
after
addition
of
reagents
to
maintain
the
indicated
pH.
Duplicates
were
run
at
pH
values
of
2,
8
and
11
(
pellets
only)
and
12.
Percent
leached
is
calculated
according
to
the
equation
presented
for
the
TCLP
results.
Relative
percent
difference
(
RPD)
for
the
experimental
duplicates
do
not
meet
the
QA
criteria
of
±
50
percent,
with
the
exception
of
the
pellet
duplicates
at
pH
12.
The
duplicate
values
appear
with
the
calculated
average
on
Figure
5­
1
and
Figure
5­
2,
and
the
trend
is
drawn
through
the
calculated
average.
Additional
tests
for
the
pellet
samples
were
run
at
pH
9
and
11
to
investigate
the
sharp
decrease
in
mercury
concentration
at
pH
10.

Percent
leached
is
calculated
according
to
the
equation
presented
for
the
TCLP
results
using
the
leachate
volume
in
Table
5­
2
to
calculate
the
liquid/
solid
ratio.
Values
in
Table
5­
2
indicate
that
0.11
to
0.53
percent
of
the
original
mercury
treated
is
leached
from
the
crushed
solid
at
pH
6,
8,
and
12,
which
did
not
undergo
recasting.
Much
smaller
losses
were
observed
at
pH
2,
6,
and
10.

A
comparison
of
the
results
for
pellets
and
crushed
samples
shows
that
mercury
concentrations
are
similar
at
pH
2,
8,
10
and
12,
and
quite
different
at
pH
4
and
6.
Laboratory
QA/
QC
(
Appendix
E)
indicates
the
analytical
results
are
valid
as
reported.
Samples
representing
the
pellets
plot
as
a
saw
tooth
pattern,
and
the
crushed
samples
show
increasing
mercury
values
up
to
pH
8
followed
by
a
decrease
and
then
an
increase
to
pH
12.
The
additional
pellet
samples
run
at
pH
9
and
11
indicate
the
minimum
at
high
pH
lies
near
11,
rather
than
10.
0.00001
0.0001
0.001
0.01
0.1
1
10
0
2
4
6
8
10
12
14
pH
%
Leached
Pellets
Crushed
Figure
5­
2
Constant
pH
Leaching
Results
for
Vendor
A
Percent
Leached
5.2
Vendor
B
Vendor
B
provided
both
an
intermediate
(
Phase
I)
and
final
waste
form
(
Phase
II).
Only
the
final
waste
form
was
used
in
the
TCLP
tests.
The
data
from
the
TCLP
analyses
are
presented
in
Table
5­
3.
The
mercury
concentrations
in
the
TCLP
leachates
were
below
the
performance
goal
of
0.025
mg/
L
Hg.

Table
5­
3
Analytical
Results
for
Vendor
B
EEI
Work
Order
01­
12­
039
TCLP
Phase
I
Phase
II
Sample
pH
TCLP
(
mg/
L)
Percent
Leached1
Sample
pH
TCLP
(
mg/
L)
Percent
Leached1
1
5.53
­
­
1
4.84
0.00588
0.000027
2
5.63
­
­
2
4.84
0.00611
0.000028
3
5.79
­
­
3
4.78
0.00284
0.000013
­
­
­
4
4.81
0.00613
0.000028
­
­
­
­
­
­
Average
­
­
Average
0.00524
0.000024
Std.
Dev.
­
­
Std.
Dev.
0.00183
­
CV
­
­
CV
34.8
­

1
Calculated
based
on
the
waste
loading
of
the
solids.
Phase
II
results
for
the
constant
pH
leach
tests
are
tabulated
in
Table
5­
4,
and
plotted
on
Figure
5­
3
on
a
concentration
basis
with
the
TCLP
results,
and
in
Figure
5­
4
as
a
percentage
of
mercury
that
leached.
Table
5­
4
reports
the
analytical
results,
the
amount
of
mercury
removed
from
the
solid
(
percent
leached),
and
the
total
volume
of
leaching
fluid,
including
the
volume
of
reagents
added
to
maintain
the
indicated
pH.
Duplicates
were
run
at
pH
values
of
2,
8
and
12,
with
the
RPD
at
pH
2
and
8
meeting
the
QA
criteria
and
the
results
at
pH
12
failing.
The
duplicate
values
appear
with
the
calculated
average
on
Figures
5­
3
and
5­
4,
and
the
trend
is
drawn
through
the
calculated
average.
Laboratory
QA/
QC
(
Appendix
E)
indicates
the
analytical
results
are
valid
as
reported.

Table
5­
4
Constant
pH
Leaching
Results
for
Vendor
B
EEI
Work
Order
01­
12­
039
Phase
II
pH
Hg
conc.
(
mg/
L)
Percent
Leached1
Leachate
Volume2
(
mL)
RPD
Sample
Dups.

2
0.00105
0.000005
550.62
39.1
2
0.00156
0.000007
500.28
4
0.00186
0.000009
504.97
6
0.00484
0.000022
501.29
8
0.0110
0.000050
503.34
27.7
8
0.00832
0.000038
501.45
10
0.0118
0.000056
525.30
12
0.143
0.000665
511.34
72.1
12
0.0672
0.000317
518.18
2
<
0.00050
­
500.77
Blank
1
Calculated
based
on
the
average
total
mercury
concentration
in
Phase
II
solids.
2
Total
volume
of
leachate,
including
addition
of
NaOH
and/
or
HNO
3
The
mercury
concentration
increases
by
two
orders
of
magnitude
as
the
pH
climbs
from
2
to
12
(
Figure
5­
3).
A
very
small
fraction
of
the
total
mercury
is
released
from
the
solids,
which
is
in
agreement
with
results
from
the
TCLP
tests.
The
volume
of
reagent
added
to
each
test
does
not
appear
to
effect
the
result.
Duplicates
at
pH
2
show
a
gross
difference
in
the
amount
of
reagent
added
to
each,
yet
the
mercury
concentrations
are
similar.
This
is
the
likely
result
of
solubility
limited
conditions.
0.001
0.01
0.1
1
10
0
2
4
6
8
10
12
14
pH
Hg
Conc.
(
mg/
L)
Phase
II
­
Elemental
Hg
0.025
mg/
L
0.2
mg/
L
0.000001
0.00001
0.0001
0.001
0
2
4
6
8
10
12
14
pH
Percent
(%)
Leached
Phase
II
Figure
5­
3
Constant
pH
Leaching
Results
for
Vendor
B
Concentration
Leached
Figure
5­
4
Constant
pH
Leaching
Results
for
Vendor
B
Percentage
Leached
5.3
Vendor
C
Table
5­
5
summarizes
the
TCLP
results
for
of
a
treated
waste
form
produced
by
Vendor
C.
Relative
to
Vendors
A
and
B,
there
is
considerably
less
variation
in
the
mercury
concentration
between
the
sample
aliquots,
as
demonstrated
by
the
reported
standard
deviation
and
coefficient
of
variation
(
CV).
The
TCLP
tests
yielded
mercury
concentrations
that
met
the
performance
goal
of
0.025
mg/
L
Hg
by
the
TCLP.

Table
5­
5
Analytical
Results
for
Vendor
C
EEI
Work
Order
01­
08­
371
TCLP
Sample
pH
TCLP
(
mg/
L)
Percent
Leached1
1
6.67
0.0129
0.00013
2
6.67
0.0133
0.00013
3
6.70
0.0152
0.00015
4
6.70
0.0154
0.00015
­
­
­

Average
0.0142
0.00014
Std.
Dev.
0.00128
­

CV
9.04
­

1
Calculated
based
on
the
waste
loading
of
mercury
in
the
treated
waste
form
Results
for
the
constant
pH
leach
tests
are
tabulated
in
Table
5­
6
and
plotted
in
Figure
5­
5
with
the
TCLP
results.
For
this
waste
form,
the
constant
pH
results
at
pH
6
and
8
are
greater
than
the
TCLP
results
obtained
at
pH
~
6.7.
This
indicates
that
the
TCLP
likely
did
not
reach
equilibrium
for
this
matrix
during
its
18­
hour
exposure
period.

Table
5­
6
reports
the
analytical
results,
the
amount
of
mercury
removed
from
the
solid
(
percent
leached),
and
the
total
volume
of
leachate,
including
the
reagents
added
to
maintain
the
indicated
pH.
Duplicates
were
run
at
pH
values
of
2,
8
and
12,
with
the
RPD
at
pH
2
and
12
meeting
the
QA
criteria
and
the
results
at
pH
8
exceed
the
desired
criteria.
This
may
be
attributed
to
sample
heterogeneity.
The
duplicate
values
appear
with
the
calculated
average
on
Figure
5­
5
and
Figure
5­
6,
and
the
trend
is
drawn
through
the
calculated
average.
Laboratory
QA/
QC
indicates
the
analytical
results
are
valid
as
reported.
The
mercury
concentration
decreases
by
three
orders
of
magnitude
as
the
pH
climbs
from
2
to
12
(
Figure
5­
5).
0.01
0.1
1
10
100
0
2
4
6
8
10
12
14
pH
Hg
Conc.
(
mg/
L)
Vendor
C
0.025
mg/
L
0.2
mg/
L
TCLP
Table
5­
6
Constant
pH
Leaching
Results
for
Vendor
C
EEI
Work
Order
01­
08­
371
&
01­
10­
360
pH
Hg
conc.
(
mg/
L)
Percent
Leached1
Leachate
Volume2
(
mL)
RPD
Sample
Dups.

2
29.7
0.39069
661.02
6.25
2
27.9
0.36725
661.44
4
0.315
0.00393
626.71
6
0.0323
0.00032
501.32
8
0.0494
0.00049
500.93
153
8
0.368
0.00367
500.72
10
0.139
0.00145
524.17
12
0.0251
0.00028
566.20
0.80
12
0.0249
0.00025
501.09
2
0.00066
­
506.86
Blank
1
Calculated
based
on
the
waste
loading
of
mercury
in
the
treated
waste
form
2
Total
volume
of
leachate,
including
addition
of
NaOH
and/
or
HNO
3
Figure
5­
5
Constant
pH
Leaching
Results
for
Vendor
C
Concentration
Leached
4Characterization
and
Evaluation
of
Landfill
Leachate
(
Draft),
SAIC,
Reston,
VA,
September
2000.
0.0001
0.001
0.01
0.1
1
0
2
4
6
8
10
12
14
pH
Percent
(%)
Leached
Vendor
C
Figure
5­
6
Constant
pH
Leaching
Results
for
Vendor
C
Percentage
Leached
5.4
Mercuric
Selenide
A
process
to
convert
mercury
into
mercuric
selenide
(
HgSe)
has
been
developed
by
Bjasta
Atervining
A
B,
Bjasta
Sweden.
In
the
process,
mercury
and
selenium
are
heated
and
allowed
to
react
in
the
vapor
phase
to
yield
a
mercuric
selenide
powder
when
cooled.
In
order
to
assess
the
leachability
of
this
type
of
treated
wasteform
over
the
range
of
pH
values
expected
at
a
RCRA
Subtitle
C
landfill,
reagent
mercury
selenide
was
obtained
and
subjected
to
constant
pH
leaching
at
pH
7
and
pH
10,
and
again
at
pH
7
and
pH
10
with
500
ppm
of
chloride
present
in
the
leachate.

While
mean
ground
water
chloride
concentrations
are
approximately
160
mg/
L,
landfill
leachates
range
from
59
to
6560
mg/
L
in
industrial
landfills
and
96
to
31,100
mg/
L
in
hazardous
waste
landfills.
4
Because
mercury
chloride
is
a
soluble
mercury
species,
these
initial
runs
were
performed
to
explore
the
effects
of
chloride
on
the
solubility
of
mercury
selenide.

The
constant
pH
leach
tests
are
tabulated
in
Table
5­
7,
and
plotted
on
Figure
5­
7
on
a
concentration
basis
with
the
TCLP
results,
and
in
Figure
5­
8
as
a
percentage
of
mercury
that
leached.
At
pH
7,
the
addition
500
ppm
of
chloride
increased
solubility
approximately
three
fold
and
almost
four
fold
at
pH
10.
This
indicates
that
the
major
ions
present
in
a
given
disposal
environment
may
significantly
impact
the
release
from
the
treated
waste
form
and
must
also
be
considered
in
the
evaluation
of
suitable
disposal
sites
in
addition
to
pH
and
redox
conditions.
Table
5­
7
Constant
pH
Leaching
Results
for
Mercury
Selenide
pH
Hg
conc.
(
mg/
L)
Percent
Leached1
Leachate
volume2
(
mL)

7
0.00656
0.000018
501.93
7
(
Cl)
0.0216
0.000060
500.98
10
0.0278
0.000308
528.84
10
(
Cl)
0.108
0.000082
512.39
10
(
Blank)
<
0.00050
500.24
1
Calculated
based
on
the
mass
of
mercury
in
the
mercury
selenide
reagent
2
Total
volume
of
leachate,
including
addition
of
NaOH
and/
or
HNO
3
Figure
5­
7
Constant
pH
Leaching
Results
for
HgSe
Concentration
Leached
0
0.00005
0.0001
0.00015
0.0002
0.00025
0.0003
0.00035
0
2
4
6
8
10
12
pH
Percent
(%)
Leached
HgSe
HgSe
with
Cl
Figure
5­
8
Constant
pH
Leaching
Results
for
HgSe
Percentage
Leached
5.5
Conclusions
Figure
5­
9
provides
the
constant
pH
leach
test
data
discussed
previously
for
all
three
vendors,
plotted
on
a
concentration
basis.
Figure
5­
10
provides
the
same
data,
plotted
as
a
percentage
of
mercury
that
leached
from
the
treated
waste
forms.
From
these
Figures,
it
is
evident
that
the
stability
of
the
mercury
in
the
treated
waste
forms
varies
widely
across
the
pH
range
tested.
For
example,
Vendor
A's
treated
waste
form
performed
better
at
pH
2
and
10­
11,
than
at
the
other
pHs
tested.
Vendor
B's
treated
waste
form
performed
best
at
low
pH,
while
Vendor
C's
waste
form
leached
less
mercury
at
high
pH
than
at
low
pH.
Clearly,
the
stability
of
mercury
in
these
treated
waste
forms
will
be
highly
dependant
on
the
disposal
conditions.
The
combination
of
site­
specific
disposal
conditions
and
appropriate
treatment
technology
must
be
considered
as
decisions
are
made
about
disposal
of
waste
bulk
elemental
mercury.
0.001
0.01
0.1
1
10
100
1000
0
2
4
6
8
10
12
14
pH
Hg
Conc.
(
mg/
L)
Vendor
A
Pellets
Vendor
A
Crushed
0.025
mg/
L
0.2
mg/
L
Vendor
B
Vendor
C
Figure
5­
9
Constant
pH
Leaching
Results
for
All
Vendors
Concentration
Leached
0.000001
0.00001
0.0001
0.001
0.01
0.1
1
10
0
2
4
6
8
10
12
14
pH
%
Leached
Vendor
A
Pellets
Vendor
A
Crushed
Vendor
B
Vendor
C
Figure
5­
10
Constant
pH
Leaching
Results
for
All
Vendors
Concentration
Leached
5.7
Additional
Information
Resources
The
following
articles
are
relevant
to
this
topic:

+"
Stabilization/
solidification
(
S/
S)
of
mercury­
containing
wastes
using
reactivated
carbon
and
Portland
cement",
Zhang,
Jian;
Bishop,
Paul
L.
Journal
of
Hazardous
Materials
(
2002),
92(
2),
199­
212.

"
Sulfide­
induced
stabilization
and
leachability
studies
of
mercury
containing
wastes",
Piao,
Haishan;
Bishop,
Paul,
Abstracts
of
Papers,
223rd
ACS
National
Meeting,
Orlando,
FL,
United
States,
April
7­
11,
2002
(
2002),
ENVR­
207.

"
Phosphate­
induced
mercury
stabilization",
Zhang,
Jian;
Bishop,
Paul
L.,
Preprints
of
Extended
Abstracts
presented
at
the
ACS
National
Meeting,
American
Chemical
Society,
Division
of
Environmental
Chemistry
(
2001),
41(
1),
422­
424.

"
Sulfide­
induced
mercury
stabilization",
Piao,
Haishan;
Bishop,
Paul
L.,
Preprints
of
Extended
Abstracts
presented
at
the
ACS
National
Meeting,
American
Chemical
Society,
Division
of
Environmental
Chemistry
(
2001),
41(
1),
428­
431.
"
Stabilization
of
radioactively
contaminated
elemental
mercury
wastes",
Stewart,
Robin;
Broderick,
Tom;
Litz,
John;
Brown,
Cliff;
Faucette,
Andrea.,
Proceedings
of
the
International
Conference
on
Decommissioning
and
Decontamination
and
on
Nuclear
and
Hazardous
Waste
Management,
Denver,
Sept.
13­
18,
1998
(
1998),
3
33­
36.

"
Mercury
stabilization
in
chemically
bonded
phosphate
ceramics",
Wagh,
Arun
S.;
Jeong,
Seung­
Young;
Singh,
Dileep,
Ceramic
Transactions
(
1998),
87(
Environmental
Issues
and
Waste
Management
Technologies
in
the
Ceramic
and
Nuclear
Industries
III),
63­
73.

"
A
Framework
for
Risk
Assessment
of
Disposal
of
Wastes
Treated
by
Solidification/
Stabilization",
Batchelor,
B.,
Environmental
Engineering
Science,
14(
1):
3­
13,
1997.

"
A
study
of
immobilization
of
four
heavy
metals
by
solidification/
stabilizatioin
with
Portland
cement",
Susan
A.
Trussell,
Ph.
D.
Dissertation,
Texas
A&
M
Univeristy,
College
Station,
Texas,
1994.

"
Immobilization
of
chromium
and
mercury
from
industrial
wastes",
Wasay,
S.
A.;
Das,
H.
A.
,
J.
Environ.
Sci.
Health,
Part
A
(
1993),
A28(
2),
285­
97.

Chemical
Fixation
and
Solidification
of
Hazardous
Wastes,
Jesse
R.
Conner,
Van
Nostrand
Reinhold,
New
York,
1990.

"
An
investigation
of
mercury
solidification
and
stabilization
in
portland
cement
using
x­
ray
photoelectron
spectroscopy
and
energy
dispersive
spectroscopy",
McWhinney,
Hylton
G.;
Cocke,
David
L.;
Balke,
Karl;
Ortego,
J.
Dale.,
Cem.
Concr.
Res.
(
1990),
20(
1),
79­
91.

"
Studies
of
zinc,
cadmium
and
mercury
stabilization
in
OPC/
PFA
mixtures",
Poon,
C.
S.;
Perry,
R.,
Mater.
Res.
Soc.
Symp.
Proc.
(
1987),
86(
Fly
Ash
Coal
Convers.
By­
Prod.),
67­
76.

"
Permeability
study
on
the
cement
based
solidification
process
for
the
disposal
of
hazardous
wastes",
Poon,
C.
S.;
Clark,
A.
I.;
Perry,
R.;
Barker,
A.
P.;
Barnes,
P.,
Cem.
Concr.
Res.
(
1986),
16(
2),
161­
72.

"
Mechanisms
of
metal
fixation
and
leaching
by
cement
based
fixation
processes",
Poon,
C.
S.;
Clark,
A.
I.;
Peters,
C.
J.;
Perry,
R.,
Waste
Manage.
Res.
(
1985),
3(
2),
127­
42.

"
Mechanisms
of
metal
stabilization
by
cement
based
fixation
processes",
Poon,
C.
S.;
Peters,
C.
J.;
Perry,
R.;
Barnes,
P.;
Barker,
A.
P.,
Sci.
Total
Environ.
(
1985),
41(
1),
55­
71.
