Document ID: EPA-HQ-RCRA-2002-0001-0032
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2002-07-05T04:00Z

1
The
NSWMA
letter
was
postmarked
January
30,
2002
but
was
not
received
by
EPA
until
mid
February.
Receipt
of
this
letter
by
EPA
may
have
been
delayed
due
to
the
irradiation
of
mail
that
was
being
sent
to
Federal
offices
in
Washington,
DC.

Virginia
Bioreactor
Project
XL
Landfills
­
Response
to
Comments
­
Page
1
UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
PROJECT
XL
VIRGINIA
BIOREACTOR
PROJECT
XL
LANDFILLS
RESPONSE
TO
COMMENTS
May
13,
2002
Introduction
The
purpose
of
this
document
is
to
present
comments
and
EPA's
responses
to
comments
on
a
proposed
Project
XL
Site­
Specific
Rule
for
Implementing
Waste
Treatment
Systems
at
Two
Virginia
Landfills
that
was
published
in
the
Federal
Register
on
December
28,
2001.

Background
On
December
28,
2001,
EPA
requested
comments
on
the
proposed
rule
for
the
Project
XL
Site­
Specific
Rulemaking
for
Implementing
Waste
Treatment
Systems
at
Two
Virginia
Landfills
(see
66
FR
67152).
The
proposal
was
to
provide
regulatory
flexibility
under
the
Resource
Conservation
and
Recovery
Act
(RCRA),
as
amended,
at
two
Virginia
landfills:
the
Maplewood
Recycling
and
Waste
Disposal
Facility,
located
in
Amelia
County,
Virginia
(Maplewood
Landfill);
and
the
King
George
County
Landfill
and
Recycling
Facility,
located
in
King
George
County,
Virginia
(King
George
Landfill).
The
Maplewood
Landfill
is
owned
and
operated
by
USA
Waste
of
Virginia,
Inc.,
and
the
King
George
Landfill
is
owned
by
King
George
County
and
operated
by
King
George
Landfills,
Inc.
USA
Waste
of
Virginia,
Inc.
and
King
George
Landfills,
Inc.
are
both
subsidiaries
of
Waste
Management,
Inc.,
and
will
be
referred
to
collectively
as
"Waste
Management".
Maplewood
Landfill
and
King
George
Landfill,
both
of
which
are
municipal
solid
waste
landfills
(MSWLFs),
will
be
referred
to
collectively
as
the
"Virginia
Project
XL
Landfills".

As
a
result
of
the
December
28,
2001
proposed
rule
for
the
Virginia
Project
XL
Landfills,
EPA
received
two
comment
letters.
The
National
Solid
Waste
Management
Association
(NSWMA)
provided
comments
in
a
letter
dated
January
28,
2002
1
.
The
NSWMA
supported
the
2
According
to
the
Federal
Register
Notice
the
comment
period
for
the
proposed
rule
closed
on
January
28,
2002.
EPA
was
contacted
via
telephone
by
NRC
on
January
28,
2002
and
agreed
to
include
their
comments
in
the
record
and
docket
but
to
designate
them
as
late.

Virginia
Bioreactor
Project
XL
Landfills
­
Response
to
Comments
­
Page
2
project
and
did
not
call
for
any
revisions.
The
NSWMA
comment
letter
states,
"NSWMA's
Landfill
Institute
supports
the
Project
XL
bioreactor
landfill
projects
proposed
for
the
Maplewood
Landfill
and
the
King
George
Landfill
in
Virginia
as
proposed
in
the
Federal
Register
on
December
28,
2001
(66
FR
67152)".
EPA
acknowledges
the
NSWMA
comments;
no
response
is
necessary.

The
National
Recycling
Coalition,
Inc.
(NRC)
provided
comments
in
a
letter
dated
February
1,
2002.
2
EPA's
complete
and
detailed
response
to
these
comments
is
contained
below.
Generally,
some
of
the
NRCs
comments
addressed
the
legal
basis
or
adequacy
of
EPA's
existing
municipal
solid
waste
landfill
(MWSLF)
criteria,
40
CFR
Part
258.
EPA
requested
and
received
comments
on
Part
258
prior
to
its
issuance,
and
addressed
these
comments
in
the
preamble
at
the
time
of
its
publication.
See
56
Fed.
Reg.
50978,
October
9,
1991.
In
any
event,
the
NRC's
comments
on
the
Part
258
MSWLF
Criteria
itself
are
beyond
the
scope
of
this
rulemaking.
Other
NRC
comments
called
for
EPA
to
establish
uniform
design
and
operating
criteria
for
all
bioreactor
landfills.
These
comments
are
also
beyond
the
scope
of
this
rulemaking,
which
addresses
only
the
Maplewood
and
King
George
County
landfills.
NRC's
comments
also
addressed
the
adequacy
of
landfill
gas
monitoring,
collection,
control
and
reporting
requirements
for
the
XL
Project.
The
proposed
rule
did
not
provide
any
flexibility
to
existing
regulations
addressing
these
requirements,
therefore
these
comments
are
also
beyond
the
scope
of
this
rulemaking.
Finally,
the
NRC
submitted
comments
on
suggested
testing
changes
for
the
XL
Project.
EPA
has
carefully
considered
these
comment
and
suggestions
and
discussed
them
with
the
Virginia
Department
of
Environmental
Quality
and
Waste
Management
and
their
consultant
in
a
number
of
phone
calls
and
a
meeting
and
site
visit
to
the
landfills.
EPA
believes
the
monitoring,
testing
and
reporting
requirements
contained
in
this
rule,
the
Final
Project
Agreement
(FPA)
and
the
State
solid
waste
and
air
permits
will
provide
sufficient
information
to
characterize
the
bioreactor
operations
at
the
Virginia
Project
XL
Landfills
and
protect
human
health
and
the
environment.
Therefore,
no
changes
have
been
made
to
the
proposed
rule.
The
remainder
of
this
RTC
document
responds
in
detail
to
comments
submitted
by
the
NRC
in
their
letter.

EPA
Responses
to
National
Recycling
Coalition
Comments
on
the
Virginia
Project
XL
Landfills
Proposed
Rule
Virginia
Bioreactor
Project
XL
Landfills
­
Response
to
Comments
­
Page
3
Executive
Summary
1.
Comment:
The
"superior
performance"
of
the
bioreactor
design
cannot
be
met
in
comparison
to
the
dry
tomb
standards
in
current
regulations
because
those
are
fatally
flawed
and
in
violation
of
the
Resource
Conservation
and
Recovery
Act.

Response:
Comments
regarding
the
legal
basis
or
adequacy
of
EPA's
current
municipal
solid
waste
landfill
(MWSLF)
criteria
are
beyond
the
scope
of
today's
rulemaking.
EPA
promulgated
regulations
implementing
sections
1008(
a)(
3),
4004(
a)
and
4010(
c)
of
the
Resource
Conservation
and
Recovery
Act
(RCRA)
in
1991,
in
accordance
with
the
requirements
of
the
Administrative
Procedure
Act.
The
time
limit
for
challenging
part
258
has
long
since
passed,
and
this
rulemaking
did
not
reopen
part
258
for
comment
or
review.
There
is
no
basis
for
the
commenters
statement
that
the
regulations
are
"fatally
flawed"
or
that
they
violate
RCRA.

For
purposes
of
the
XL
Project
that
is
the
subject
of
today's
rule,
the
part
258
criteria
are
the
only
basis
for
evaluating
whether
this
project
meets
the
"superior
performance"
criterion
of
Project
XL.
Under
Project
XL,
EPA
may
provide
project­
specific
flexibility
to
existing
rules,
regulations
and
guidance
provided
the
project
meets
all
the
Project
XL
criteria.
As
set
forth
in
the
Final
Project
Agreement
http://
www.
epa.
gov/
ProjectXL/
virginialandfills/
page1.
htm,
EPAhas
determined
that
this
project
meets
the
"superior
environmental
performance"
criteria.

2.
Comment:
The
artificial
cost
collar
imposed
on
the
design
and
operation
of
the
bioreactors
in
order
to
keep
their
net
costs
less
than
those
of
dry
tomb
landfills
effectively
prioritizes
costs
over
economics
(sic),
and,
this
too,
is
impermissible
under
law.

Response:
The
commentor
assumes
a
"cost
collar"
but
it
is
unclear
what
the
commentor
means
by
this
term.
As
stated
in
the
preamble
to
the
proposed
rule,
Project
XL
includes
"cost
savings
and
paperwork
reduction"
as
one
of
eight
criteria
for
determining
whether
a
project
proposal
should
be
accepted,
along
with
"superior
environmental
performance,"
and
"
avoidance
of
shifting
risk
burden"
to
name
two
others.
66
Fed.
Reg.
67154.
EPA
disagrees
that
the
proposed
rule,
or
the
XL
project
to
which
it
applies,
prioritizes
costs
over
environmental
protection.

3.
Comment:
EPA
must
establish
uniform
protocols
for
any
XL
or
Cooperative
Research
and
Development
Agreement
(CRADA)
bioreactor
tests
to
insure
that
the
designs
provide
additional
layers
of
conservatism
to
make
this
type
of
landfill
"fool
proof"
and
the
tests
produce
all
relevant
information
with
statistical
techniques
for
reliability.

Response:
EPA
is
currently
supporting
bioreactor
testing
under
the
Project
XL
and
CRADA
programs.
EPA
disagrees
that
the
Agency
should
establish
"uniform
protocols"
for
testing
bioreactor
technology
under
these
programs.
The
monitoring
requirements
for
each
program
and
the
projects
under
these
programs
are
similar,
but
not
the
same.
Each
project
is
slightly
different
and
therefore
the
requirements
differ
somewhat.
However,
there
are
common
requirements
of
bioreactor
projects
under
Project
XL
and
CRADA
to
ensure
that
these
projects
do
not
pose
an
Virginia
Bioreactor
Project
XL
Landfills
­
Response
to
Comments
­
Page
4
unreasonable
risk
to
human
health
and
the
environment.
For
example,
all
the
projects
require
the
monitoring
of
the
leachate
head
on
the
liner
as
well
as
leachate
quality
and
quantity,
landfill
gas
composition
and
quantity
collected,
moisture
and
temperature
sensors,
waste
characteristics
as
it
changes
over
time,
waste
settlement
as
well
as
ground
water
quality.
Furthermore,
as
EPA
stated
in
its
notice
modifying
its
Guidance
for
Project
XL,
62
Fed.
Reg.
19872
(April
23,
1997),
EPA
expects
data
and
experiences
that
will
help
the
Agency
make
sound
decisions
as
we
look
for
ways
to
improve
the
current
regulatory
system."
The
Federal
Register
notice
also
explained
that
another
of
the
objectives
of
Project
XL
is
to
"transfer
successful
approaches
into
the
current
system
of
environmental
protection."
If
EPA
decides
in
the
future
that
the
federal
municipal
solid
waste
landfill
criteria
in
part
258
should
be
amended
to
allow
more
widespread
implementation
of
bioreactor
technology,
the
information
learned
from
various
approaches
in
Project
XL
and
CRADA
projects
will
be
the
basis
for
determining
what
uniform
criteria
should
apply.

4.
Comment:
Among
the
design
changes
that
the
NRC
believes
ought
to
be
included
in
protocols
are:
pre­
shredding
the
incoming
waste
load;
lighter
in­
place
compaction
of
the
waste
load;
double
composite
liners;
4:
1
side
slopes;
and
greater
redundancy
in
leachate
collection
lines.

Response:
It
is
important
to
note
that
the
tests
cells
in
the
Project
XL
bioreactor
landfills
are
already
constructed,
have
been
filled
with
waste
and
are
no
longer
actively
receiving
waste.
EPA
does
not
believe
that
any
design
changes
are
required
for
the
Virginia
Project
XL
Landfills
in
order
to
conduct
the
bioreactor
testing
at
these
sites.
Bioreactor
operating
and
testing
requirements
for
the
XL
Project
are
described
in
the
FPA,
the
Final
Site
Specific
Rule
and
the
VADEQ
solid
waste
and
air
permits
for
the
Virginia
Project
XL
Landfills.
As
previously
stated,
one
purpose
of
this
XL
project
is
to
test
and
compare
various
design
elements
to
determine
what
design
criteria
should
apply
generally
to
bioreactors,
if
EPA
decides
in
the
future
to
amend
part
258.
Since
the
waste
is
already
in
place
in
the
bioreactor
test
cells
EPA
does
not
agree
that
preshredding
or
lighter
in­
place
compaction
could
or
should
be
required
for
this
XL
project.
See
response
to
Comment
13
(a)
regarding
pre­
shredding
of
waste
and
Comment
13
(b)
regarding
compaction.
There
is
an
existing
double
(and
in
the
case
of
the
King
George
Landfill
a
triple)
synthetic
liner
under
the
Virginia
Project
XL
Landfill
cells.
See
response
to
Comment
13
(c)
regarding
composite
liners.
A
slope
stability
analysis
was
conducted
for
both
landfills
and
considered
the
effect
of
bioreactor
operations
in
the
test
cells.
The
slope
stability
analysis
for
both
landfills
was
determined
to
exceed
the
value
of
1.5
recommended
by
EPA.
See
response
to
Comment
13
(d)
regarding
side
slopes.
The
existing
design
of
the
leachate
collection
systems
provides
for
redundant
drainage
as
is
explained
in
the
response
to
Comment
13
(e)
below.

5.
Comment:
Among
the
test
changes
that
the
NRC
proposes
are:
statistical
sampling
of
bore
samples
to
produce
reliable
data
on
site
stabilization
and
gas
emissions;
and
in­
line
camera
surveys
of
the
leachate
collection
lines.

Response:
The
proposed
rule
states
the
operator
of
the
landfill
shall
collect
representative
samples
of
the
landfill
waste
in
the
test
areas
on
an
annual
basis
and
analyze
the
samples
for
the
following
solid
waste
stabilization
and
decomposition
parameters:
Moisture
Content,
Biochemical
Virginia
Bioreactor
Project
XL
Landfills
­
Response
to
Comments
­
Page
5
Methane
Potential,
Cellulose,
Lignin,
Hemi­
cellulose,
Volatile
Solids
and
pH.
EPA
believes
that
the
testing
agreed
to
in
the
Final
Project
Agreement
will
provide
reliable
and
representative
data
on
site
stabilization
and
gas
emissions.
The
monitoring
and
testing
requirements
specified
in
the
proposed
rule
go
beyond
the
requirements
specified
in
existing
regulations.
See
response
to
Comment
14
regarding
waste
stabilization
and
Comments
13
(f)
and
15
regarding
gas
emission.
The
proposed
requirements
regarding
monitoring
and
testing
reflect
what
was
agreed
to
by
the
stakeholders
in
the
Final
Project
Agreement
(FPA)
which
was
announced
for
public
comment
on
September
8,
2000
(65
Fed.
Reg.
54520).
The
commentor
did
not
submit
comments
on
the
proposed
FPA.

I
­
Correction
of
the
Fundamental
Assumption
6.
Comment
Summary:
Misreading
of
Superior
Performance
Criteria
(page
5)

The
commentor
states
that
because
the
current
landfill
rules
in
40
CFR
part
258
are
the
baseline
against
which
to
evaluate
whether
this
XL
project
meets
the
"superior
performance"
criteria,
"whole
sections
of
[the
Final
Project]
Agreement
(FPA)
"must
be
largely
revamped."
The
commentor
also
argues
that
"the
problem
with
simply
following"
the
`Superior
Environmental
Performance'
criteria
guideline
in
this
case
is
that
it
does
not
take
into
consideration
"whether
EPA's
current
rules
that
are
otherwise
applicable
protect
the
environment."

Response:
This
comment
is
beyond
the
scope
of
this
rulemaking.
See
response
to
Executive
Summary,
Comment
1
above.

7.
Comment
Summary:
Systemic
Long­
Term
Fallacy
of
Dry
Tomb
Designs
(pages
5­
8)

The
commentor
argues
that
because
landfill
liners
"will
ultimately
fail"
EPA
rules
which
include
"dry
tomb"
designs
violate
RCRA
and
should
not
be
used
as
the
baseline
for
this
rulemaking.
The
commentor
cites
several
sources
which
describe
the
rules
prescribing
"dry
tomb"
landfills
as
protecting
the
environment
initially,
but
as
also
failing
to
address
the
long­
term
potential
for
leakage
of
leachate
and
landfill
gas.

Response:
These
comments
are
beyond
the
scope
of
today's
rulemaking,
as
they
question
the
existing
rules
and
not
today's
rulemaking.
See
Response
to
Comment
1
above.
However,
EPA
notes
that
the
commentor's
arguments
in
fact
support
today's
rule.
This
site­
specific
rule
is
intended
to
allow
for
the
testing
of
technologies
that,
if
successful,
may
be
useful
in
reducing
the
long­
term
risks
from
MSWLFs.
As
stated
in
the
proposal,
"Several
studies
have
shown
that
leachate
quality
improves
over
time
when
leachate
is
recirculated
on
a
regular
basis.
For
all
of
these
reasons
bioreactors
are
expected
to
decrease
potential
environmental
risks
and
costs
associated
with
leachate
management,
treatment
and
offsite
disposal.
Additionally,
use
of
bioreactor
techniques
is
expected
to
shorten
the
length
of
time
the
liner
will
be
exposed
to
leachate
and
this
should
lower
the
long
term
potential
for
leachate
migration
into
the
subsurface
environment.
Bioreactors
are
also
expected
to
reduce
post­
closure
care
costs
and
risks,
due
to
the
Virginia
Bioreactor
Project
XL
Landfills
­
Response
to
Comments
­
Page
6
accelerated,
controlled
settlement
of
the
solid
waste
during
landfill
operation.
Finally,
bioreactors
provide
for
greater
opportunity
for
recovery
of
methane
gas
for
energy
production
since
a
larger
quantity
of
methane
is
produced
earlier
than
in
a
normal
MSWLF."
66
FR
67155.

8.
Comment
Summary:
Other
Short­
Term
Design
Failings
(page
9­
13)

(a)
Air
Emissions.

"Chief
among
them
is
the
issue
of
air
emissions
from
landfills.
The
impression
that
has
been
left
is
that
the
regulation
in
40
CFR
Part
60
Subpart
WWW,
requiring
a
piping
system
intended
to
extract
gas
in
large
landfills,
resolves
concerns
over
landfill
gas
emissions.
Those
regulations
do
not,
however,
create
any
emission's
limit
other
than
certain
piping
design
requirements.
Notwithstanding
that
fact,
the
Agency
has
assumed
that
the
collection
efficiency
is
75%,
without
any
factual
basis
for
that
conclusion."
The
commentor
provides
information
regarding
variations
in
landfill
gas
collection
efficiencies
and
reasons
for
this
variation.
The
commentor
also
noted
that
"EPA
rules
mandating
the
installation
of
gas
collection
systems
only
covered
54%
of
the
waste
in
the
ground
in
2000
..."
andcommentedonthecontributionof
landfill
gases
to
global
warming
and
distribution
of
mercury
and
other
hazardous
compounds
into
the
atmosphere.

Response:
Similar
to
the
commentor's
statements
regarding
the
adequacy
of
the
existing
MSWLF
criteria
in
40
CFR
part
258,
the
comments
in
this
section
address
the
adequacy
of
existing
regulations
implementing
the
Clean
Air
Act
at
40
CFR
part
60
Subpart
WWW.
These
comments
are
beyond
the
scope
of
today's
rulemaking.
Neither
today's
rule
nor
this
XL
project
as
a
whole,
provide
for
any
flexibility
regarding
landfill
gas
monitoring,
collection
and
control
required
by
existing
regulations.
This
project
must
comply
with
all
applicable
existing
air
regulations.
As
discussed
in
the
preamble
to
the
proposed
rule,
Waste
Management's
obligations
with
respect
to
landfill
gas
will
be
set
forth
in
a
Federally
Enforceable
State
Operating
Permit
(FESOP).
(66
FR
67157)
The
Virginia
Department
of
Environmental
Quality
(VADEQ)
is
the
regulatory
agency
which,
under
the
federal
Clean
Air
Act,
has
air
permitting
authority
for
both
landfills.
The
VADEQ
was
a
major
stakeholder
in
the
XL
Project
and
has
issued
a
New
Source
Review
Permit
9
VAC
5­
80­
10
(NSR)
for
the
King
George
Landfill
which
contains
the
enforceable
parameters
and
requirements
implementing
the
New
Source
Performance
Standards
(NSPS)
regarding
gas
collection,
control
and
monitoring.
In
addition,
on
July
31,
2001,
VADEQ
issued
a
Title
V
Operating
Permit
9
VAC
5­
80­
50
et.
seq.
(Title
V),
for
the
King
George
Landfill.
Both
the
Title
V
permit
and
the
underlying
NSR
permit
issued
by
VADEQ
are
considered
Federally
enforceable.
An
NSR
Permit
for
the
Maplewood
Landfill
is
under
development.
An
NSR
Permit
will
be
in
place
for
each
landfill
prior
to
the
addition
of
liquids.
It
is
important
to
note
that
an
active
gas
collection
system
is
already
in
place
and
operating
at
both
landfills.
Details
on
the
piping
system
for
the
LF
gas
extraction
system
are
contained
in
the
monitoring
plan
in
the
NSPS
permits
for
the
landfills.
There
is
currently
beneficial
reuse
of
the
LF
gas
at
the
Maplewood
LF
which
is
used
for
energy
production
and
WM
is
working
towards
the
beneficial
reuse
of
the
methane
from
the
King
George
LF.
Virginia
Bioreactor
Project
XL
Landfills
­
Response
to
Comments
­
Page
7
(b)
Leachate
Collection
Systems
"A
continuing
threat
to
the
ability
of
these
systems
to
remove
excess
liquids
is
the
problem
of
clogging
of
the
pipes
from
microbial
action
and
clog
materials,
exacerbated
by
organic
matter
and
calcium
concentrations
in
the
waste
load.
That
is
the
reason
why
it
is
absolutely
essential
that
these
lines
be
cleaned
out
at
least
annually
for
as
long
as
the
site
remains
biologically
active
in
order
to
preserve
their
functionality.

"However,
the
ability
to
clean
out
the
collection
pipes
becomes
substantially
more
difficult
as
the
length
of
the
pipes,
and
the
number
of
joints
and
the
problems
laying
the
segments
in
a
straight
line,
increases.
Yet,
to
our
knowledge,
EPA
has
never
undertaken
any
systematic
technical
review
to
validate
the
maximum
length
which
collection
pipes
can
be
reliably
cleaned
out
overtime....
Combinedwithsteep3:
1,
insteadof4:
1,
sideslopes,
thesedesignchangeshave
facilitated
the
construction
of
mega­
landfills
covering
thousands
of
acres,
hundreds
of
feet
high.
.
.
.
.
Moreover,
so
far
as
we
are
aware,
neither
has
any
regulatory
consideration
been
given
to
how
a
clogged
line
would
be
repaired
in
a
mega­
fill
that
would
require
digging
out
a
cone­
shaped
cavity
through
hundreds
of
feet
of
garbage
to
provide
clearance
for
workers
to
access
the
clogged
pipe
segment."

Response:
This
comment
is
beyond
the
scope
of
today's
rulemaking.
Today's
rulemaking
concerns
only
the
site­
specific
requirements
for
operation
of
specific
existing
cells
in
the
King
George
and
Maplewood
landfills
as
bioreactor
landfills.
The
commentor's
complaints
about
leachate
collection
systems
are
general
in
nature.
Existing
regulations
(40
CFR
258.28(
a)(
2))
allow
leachate
recirculation
in
MSWLFs
that
meet
the
design
specifications
in
section
258.40(
a)(
2),
which
include
the
requirement
of
a
leachate
collection
system
that
can
ensure
a
hydraulic
head
(leachate
layer)
above
the
liner
of
30
centimeters
(cm)
or
less,
i.
e.
approximately
12
inches.

With
respect
to
this
proposal,
the
requirement
of
maintaining
less
than
30
cm
of
head
on
the
liner
in
specifically
included
(40
CFR
258.41(
c)(
1)).
Waste
Management
will
not
be
allowed
to
add
liquids
if
the
requirements
for
the
head
on
the
liner
are
exceeded.
EPA
does
not
agree
that
it
is
necessary
to
specify
how
such
a
leachate
collection
system
must
be
designed.
It
is
the
responsibility
of
the
landfill
owner/
operator
to
comply
with
the
leachate
control
requirements
regardless
of
the
length
of
pipes
or
number
of
joints.

(c)
Monitoring
Wells.
"EPA
requires
groundwater
monitoring
wells
in
order
to
detect
leakage
before
it
reaches
groundwater,
generally
150
meters
from
the
direction
the
groundwater
will
flow
from
the
landfill
and
no
more
than
200
feet
apart."
The
commentor
argued
that
monitoring
wells
as
much
as
200
feet
apart
have
an
exceedingly
low
probability
of
detecting
a
leak
from
"a
typical
two­
foot
long
tear
or
rip
.
.
.
in
a
sand
aquifer
system"
that
would
only
be
expected
"to
spread
laterally
about
ten
feet
within
150
meters
of
the
source."

Response:
This
comment
is
beyond
the
scope
of
today's
rulemaking.
Today's
rulemaking
Virginia
Bioreactor
Project
XL
Landfills
­
Response
to
Comments
­
Page
8
concerns
only
the
site­
specific
requirements
for
operation
of
specific
existing
cells
in
the
King
George
and
Maplewood
landfills
as
bioreactor
landfills.
These
comments
concern
the
commentor's
view
of
the
existing
MSWLF
criteria
with
respect
to
detection
monitoring
requirements
and
do
not
address
today's
rulemaking.

With
respect
to
today's
rule,
the
Project
sponsor
did
not
request
any
regulatory
flexibility
with
regard
to
groundwater
monitoring
at
the
Virginia
Project
XL
Landfills.
Waste
Management
is
required
to
comply
with
all
existing
regulations
for
ground
water
monitoring
at
the
two
sites.
EPA
considers
groundwater
monitoring
an
important
indicator
for
monitoring
environmental
impact.
As
of
February
2002
there
are
12
monitoring
wells
at
the
Maplewood
Landfill
and
14
monitoring
wells
at
the
King
George
County
Landfill.
The
wells
are
sampled
on
a
quarterly
basis.
The
state
solid
waste
permit
contains
complete
information
on
the
ground
water
monitoring
programs
at
the
Virginia
Project
XL
Landfills.
EPA
has
added
figures
to
the
docket
for
this
rule
that
depict
the
ground
water
monitoring
well
locations
on
the
Virginia
Project
XL
Landfill
properties.

9.
Comment
Summary:
Proper
Base
Line
Assumption
for
Bioreactor
Designs
and
Tests
(page
14)

"The
design
must
be
determined
not
on
the
basis
of
whether
it
poses
less
of
a
threat
to
the
environment
than
current
rules,
but
rather
whether
"there
is
no
reasonable
probability
of
adverse
effects
on
health
or
the
environment
from
disposal
of
solid
waste"
under
the
modified
rules,
regardless
of
whether
the
threat
is
less."
It
must
be
structured
so
as
to
provide
reliable
data
on
which
to
pattern
new
rules
that
would
be
applicable
to
all
applicants
for
landfills
after
the
discredited
dry
tomb
standards
are
repealed.

Response:
See
response
to
Executive
Summary,
Comment
1.
The
criteria
in
part
258
set
out
the
requirements
that
implement
section
4004(
a)
of
RCRA
based
on
a
determination
that
"there
is
no
reasonable
probability
of
adverse
effects
on
health
or
the
environment
from"
facilities
meeting
these
requirements.
The
part
258
criteria
are
the
proper
and
only
basis
for
evaluating
whether
this
project
meets
the
"superior
performance"
criterion
of
Project
XL.
Today's
rulemaking
is
for
the
purpose
of
implementing
this
project
as
two
specific
landfill
sites
and
is
not
a
rule
to
define,
as
a
general
rule,
the
requirements
applicable
to
all
bioreactor
landfills.

II
Proposed
Changes
in
Bioreactor
Design
and
Operation
10.
Comment:
A
reading
of
the
technical
documents
in
this
docket
provides
little
inkling
of
the
urgent
need
for
any
special
care
in
the
design
or
operation
of
a
bioreactor.
But,
as
explained
below,
we
vigorously
disagree
with
this
characterization
and,
because
of
the
actual
real­
world
problems
in
bioreactors,
we
strongly
urge
that
the
conditions
of
their
design
and
operation
be
made
foolproof.
Virginia
Bioreactor
Project
XL
Landfills
­
Response
to
Comments
­
Page
9
Response:
The
commentor
misconstrues
the
purpose
of
today's
rule.
EPA
is
not
promulgating
a
rule
setting
forth
generally
applicable
design
and
operation
criteria
for
bioreactor
landfills.
Rather,
today's
rulemaking
is
a
site­
specific
rule
to
allow
specified
techniques
to
be
tested
at
particular
existing
landfill
facilities.
Based
on
the
technical
support
documents
and
the
Project
XL
proposal
information
contained
in
the
Docket
for
this
proposed
rule
including
the
Slope
Stability
studies
for
the
test
cells
that
will
be
operated
as
bioreactor
landfills
(Docket
Numbers
4.
5
and
4.6),
EPA
believes
that
today's
rule
is
protective
of
human
health
and
the
environment.
Furthermore,
the
monitoring
and
testing
requirements
in
the
rule
will
allow
for
evaluation
of
the
processes
taking
place
in
the
test
cells
and
provide
EPA
with
detailed
information
on
bioreactor
operations.
As
the
commentor
notes,
bioreactors
are
currently
operating
in
different
locations
in
the
United
States.
Table
2
in
the
FPA
contains
a
Summary
of
Field
Scale
Leachate
Recirculation
and
Bioreactor
Projects.
Numerous
technical
writings
on
the
subject
show
that
safe
and
effective
operation
is
achievable.
The
commentor
rightly
states
that
technical
challenges
remain,
and
bioreactors
can
be
operated
improperly.
This
need
can
be
answered,
in
part,
by
projects
like
this
one
that
will
provide
additional
data
on
bioreactor
operations
under
measured
and
controlled
conditions.

11.
Comment
Summary:
Advocate
Role
Inappropriate
(pages
15­
16)

The
commentor
notes
that
EPA
listed
six
reasons
why
bioreactor
technology
will
provide
environmental
benefits
but
did
not
acknowledge
any
of
the
numerous
and
widely
recognized
problems
of
bioreactors.
The
commentor
believes
that
the
record
creates
the
impression
that
EPA
is
acting
as
an
advocate
for
an
untested
and
highly
controversial
technology.
The
commentor
views
EPA's
decision
to
approve
the
Virginia
Project
XL
Landfills
as
a
product
of
combined
function
of
promotion
and
regulation,
which
the
commentor
believes
is
contrary
to
EPA's
obligation
to
independently
and
objectively
evaluate
each
application
on
its
merits.

Response:
EPA
objectively
evaluated
the
project
XL
proposal
for
the
VA
landfills
project
and
determined
that
the
project
meets
the
criteria
for
acceptance
under
Project
XL.
The
basis
for
EPA's
determination
with
respect
to
this
project
is
set
out
in
a
Letter
to
Waste
Management,
Inc
from
Thomas
C.
Voltaggio,
regarding
selection
of
the
Waste
Management,
Inc.
Project
XL
Proposal,
August
3,
2000
and
in
the
Final
Project
Agreement.
The
August
3,
2000
Letter
is
in
the
Docket
for
this
rule
and
posted
on
the
EPA
website
at:
http://
www.
epa.
gov/
ProjectXL/
virginialandfills/
voltaggio.
pdf.
The
draft
FPA
was
made
available
for
public
review
and
comment
(65
FR
54520,
Sept.
8,
2000).
The
FPA
is
also
contained
in
the
Docket
for
this
rule
and
is
posted
on
the
EPA
website
at:
http://
www.
epa.
gov/
ProjectXL/
virginialandfills/
fpa.
pdf.
The
commentor
did
not
submit
comments
on
the
draft
Final
Project
Agreement
(FPA)
in
response
to
the
Agency's
Notice
of
Availability
of
the
FPA
and
solicitation
of
public
comments.
Nevertheless,
EPA
disagrees
that
its
approval
of
the
Virginia
Project
XL
Landfills
project
was
inappropriate,
nor
does
EPA
agree
that
it's
role
is
one
of
advocacy.
As
explained
in
the
above
Federal
Register
notice
concerning
the
FPA,
Project
XL
"gives
regulated
entities
the
opportunity
to
develop
alternative
strategies
that
will
replace
or
modify
specific
regulatory
requirements
on
the
condition
that
they
produce
greater
Virginia
Bioreactor
Project
XL
Landfills
­
Response
to
Comments
­
Page
10
environmental
benefits."
As
further
explained
in
the
preamble
to
the
proposed
site­
specific
rule
for
this
project,
"these
efforts
are
crucial
to
the
Agency's
ability
to
test
new
regulatory
strategies
that
reduce
regulatory
burden
and
promote
economic
growth
while
achieving
better
environmental
and
public
health
protection."
66
FR
67154.

By
promulgating
today's
rule,
EPA
is
not
advocating
the
wide
spread
use
of
bioreactor
landfills
for
MSW
waste.
Promulgation
of
a
site­
specific
rule
to
allow
an
alternative
approach
in
the
context
of
a
given
XL
project
is
not
an
indication
that
EPA
plans
to
adopt
that
approach
as
a
general
matter.
It
would
be
inconsistent
with
the
forward­
looking
nature
of
these
pilot
projects
to
adopt
such
innovative
approaches
prematurely
on
a
widespread
basis
without
first
determining
whether
or
not
they
are
potentially
viable
in
practice
and
successful
for
the
particular
projects
that
embody
them.

Alternative
policy
approaches
and/
or
interpretations,
on
a
limited,
site­
or
state­
specific
basis
and
in
connection
with
a
carefully
selected
pilot
project,
is
consistent
with
the
expectations
of
Congress
about
EPA's
role
in
implementing
the
environmental
statutes
(so
long
as
EPA
acts
within
the
discretion
allowed
by
the
statute).
Congress
recognizes
that
there
is
a
need
for
experimentation
and
research,
as
well
as
ongoing
reevaluation
of
environmental
programs,
is
reflected
in
a
variety
of
statutory
provisions,
e.
g.,
Sec.
8001
of
RCRA,
(42
U.
S.
C.
6981).

12.
Comment
Summary:
Special
Challenges
of
Bioreactors
(pages
16­
17)

"In
order
to
attempt
to
accelerate
decomposition
in
the
ground,
the
moisture
content
and
temperature
of
the
waste
load
must
be
doubled,
increasing
the
weight
of
the
waste
load
by
approximately
one­
third,
in
an
unstable
and
dynamic
state
in
which
there
is
differential
settlement
on
the
bottom
liner,
the
possibility
of
anticipated
seepages
threatening
side
wall
stability,
the
complexity
of
achieving
adequate
gas
extraction,
and
so
on."
The
commentor
summarized
two
instances
where
breaches
occurred
in
landfills
where
liquids
were
being
recirculated.

Response:
EPA
is
aware
of
the
issues
mentioned
above
as
being
concerns
for
the
operation
of
bioreactor
landfills.
It
is
for
these
reasons
that
EPA
and
the
other
stakeholders
have
agreed
to
evaluate
this
technology
and
gather
data
on
these
issues
at
the
Virginia
Project
XL
Landfills
and
other
Project
XL
bioreactor
landfill
test
sites.

EPA
agrees
that
careless
injection
of
large
quantities
of
leachate
could
lead
to
slope
stability
problems
and
these
issues
must
be
taken
into
account
at
all
phases
of
bioreactor
operation.
See
the
response
to
Comment
13
B,
13
D
and
13
G
regarding
compaction,
side
slope
and
buffer
zones
below.

Waste
Management
has
installed
temperature
monitoring
wells
in
several
locations
and
depths
throughout
the
test
areas
at
both
landfills
and
will
be
monitoring
and
recording
the
temperature
at
these
locations.
Virginia
Bioreactor
Project
XL
Landfills
­
Response
to
Comments
­
Page
11
Based
on
the
volume
and
density
of
waste
measured
in
the
test
areas
and
the
volume
and
mass
of
liquid
that
is
proposed
to
be
added
to
the
Maplewood
and
King
George
Landfills
on
an
annual
basis,
it
is
calculated
that
the
weight
of
waste
in
the
test
areas
would
increase
by
1.
7%
and
2.
6%
at
the
Maplewood
and
King
George
Landfills,
respectively
(Site
Visit
to
Maplewood
and
King
George
Landfills).

In
addition
to
the
two
landfill
failures
cited
by
the
commentor,
there
are
several
other
bioreactor
landfills
that
are
operating
without
incident.
They
include
Yolo
County
in
California;
Florida
Center
for
Solid
and
Hazardous
Management,
Bioreactor
Landfill
Demonstration
Project;
Outer
Loop
Landfill
in
Kentucky
and
the
Delaware
Solid
Waste
Authority,
Sussex
Landfill
which
historically
recirculated
leachate.
Table
2
in
the
FPA
contains
a
Summary
of
Field
Scale
Leachate
Recirculation
and
Bioreactor
Projects.
Technical
results
of
this
project
coupled
with
other
landfill
bioreactor
projects
will
lead
to
design
and
operational
guidance
that
the
commentor
desires.

Finally,
this
rule
is
only
allowing
bioreactor
landfill
operations
at
two
test
locations
in
Virginia.
This
rule
is
not
meant
to
address
all
design
concerns
for
a
bioreactor
landfill
and
they
are
clearly
not
meant
to
"serve
as
the
basis
for
the
second
generation
landfill".

13.
Comment
Summary:
Need
to
Upgrade
Dry
Tomb
Specifications
for
Bioreactors
(pages
18­
23)

The
commentor
stated
that
for
a
rule
change
for
the
second
generation
landfill
design
that
would
be
applied
across
thousands
of
facilities
over
time,
a
heightened
level
of
additional
conservatism,
beyond
that
in
dry
tomb
design,
must
be
built
into
bioreactor
design
specifications,
and
that
this
contrasts
with
the
cost
constraint
on
bioreactor
design
specifications
incorporated
into
the
VA
landfills
project.
The
commentor
advocated
that
EPA
set
up
a
generic
docket
for
conducting
an
investigation
that
can
provide
a
factual
basis
to
set
up
a
generic
protocol
with
which
to
evaluate
project
applications
and
compare
results
of
various
experiments.
The
commentor
also
stated
that
no
further
XL
or
CRADA
bioreactor
projects,
including
the
Virginia
Project
XL
Landfills
project,
should
be
approved.
The
commentor
proposed
a
set
of
recommendations
for
changing
the
design
and
operation
requirements
in
40
CFR
part
258
with
respect
to
(a)
pre­
shredding,
(b)
compaction,
(c)
liner,
(d)
side
slopes,
(e)
leachate
collection,
(f)
gas
collection,
(g)
buffer
zones,
and
(h)
final
flush.

Response:
These
comments
are
beyond
the
scope
of
today's
rulemaking.
As
previously
stated,
EPA
did
not
propose
and
is
not
promulgating
today
a
rule
of
general
applicability
regarding
bioreactor
design
specifications.
Moreover,
the
comments
regarding
the
XL
Project
that
is
the
subject
of
today's
rule
concern
the
terms
of
the
Final
Project
Agreement
(FPA).
The
commentor
did
not
submit
any
comments
on
the
draft
FPA
in
response
to
EPA
Federal
Register
notice
and
request
for
comments.
However,
although
the
commentor
made
no
mention
of
any
aspect
of
the
proposed
site­
specific
rule
in
the
comments,
the
commentor
referenced
the
VA
Project
XL
Landfills
in
its
broad
discussions
of
how
the
part
258
criteria
should
be
changed
prospectively
for
design
of
landfills
that
will
be
operated
as
bioreactors.
To
the
extent
these
comments
can
be
Virginia
Bioreactor
Project
XL
Landfills
­
Response
to
Comments
­
Page
12
applied
to
today's
rule,
EPA
responds
in
the
context
of
responding
to
those
recommendations.

Regarding
a
generic
protocol
and
docket
for
bioreactor
projects,
EPA
notes
that
the
Office
of
Solid
Waste
and
the
Office
of
Research
and
Development
are
developing
a
centralized
Internet
page
for
bioreactor
landfills.
EPA
plans
to
make
annual
reports
for
each
project
available
to
the
public.

(a)
Pre­
shredding
of
waste
Comment:
Pre­
shredding
is
needed
to
maximize
distribution
of
liquid
and
promote
decomposition,
due
to
the
heterogeneous
nature
of
solid
waste,
the
omnipresence
of
plastic
bags,
extremely
high
densities,
and
the
difficulty
of
evenly
distributing
water
in
trench
works
throughout
the
waste
load.

Response:
As
previously
stated,
these
comments
are
beyond
the
scope
of
this
rulemaking.
However,
if
the
commentor
intended
that
today's
rule
should
require
that
waste
placed
in
the
VA
Project
XL
Landfills
cells
to
be
operated
as
bioreactors
be
pre­
shredded,
such
a
requirement
would
not
be
possible.
The
test
cells
that
are
the
subject
of
today's
rule
are
generally
inactive,
meaning
that
they
do
not
and
will
not
receive
waste
on
an
ongoing
basis
during
this
XL
Project.
Additional
fill
may
be
added
to
maintain
positive
drainage
on
the
surface
of
the
landfill
during
the
project,
however
this
will
be
a
small
fraction
of
the
waste
volume
in
the
cells
and
a
shredding
requirement
for
additional
fill
would
not
provide
useful
information
for
evaluating
the
effect
of
shredding.
None
of
the
existing
waste
in
the
landfill
test
cells
was
shredded.
Moreover,
since
the
existing
waste
was
not
shredded,
this
will
provide
for
a
rigorous
test
of
bioreactor
operations.

(b)
Compaction
Comment:
FPA
did
not
include
a
discussion
of
the
point
at
which
increased
densities
prevent
liquid
additions
from
reaching
a
part
of
the
load
where
compaction
is
greatest.
Detailed
information
on
what
those
density
limits
are
and
what
operational
practices
are
necessary
to
keep
compression
below
those
limits
in
all
parts
of
the
affected
load
are
necessary
before
operational
practices
can
be
established.

Response:
To
the
extent
that
this
comment
requests
that
this
project
establish
operational
practices
for
all
bioreactors,
this
comment
is
beyond
the
scope
of
today's
rulemaking.
Since
little,
if
any,
additional
waste
will
be
added
to
the
cells
during
the
XL
Project,
EPA
does
not
believe
that
density
limits
or
operational
practices
are
needed
for
this
project.
Compression,
settlement
and
waste
characteristics
will
be
monitored
during
the
XL
Project.
Among
the
goals
for
the
XL
Project
as
stated
in
the
FPA
are
the
uniform
distribution
of
leachate
throughout
the
waste
mass
in
the
test
areas.
The
Project
will
evaluate
the
relative
effectiveness
of
different
horizontal
trench
designs
for
uniformly
distributing
leachate
throughout
the
waste
mass,
identify
several
leachate
delivery
options
to
simplify
operations
and
provide
monitoring
features
within
the
horizontal
trenches
so
that
liquid
head
and
distribution
rate
within
the
trenches
can
be
measured
and
Virginia
Bioreactor
Project
XL
Landfills
­
Response
to
Comments
­
Page
13
documented.
The
application
capacity
of
the
trenches
has
been
estimated
using
the
methodology
described
by
Maier
[1998].
This
evaluation
considered
the
moisture
content
of
the
waste,
the
hydraulic
properties
of
the
waste,
the
moisture
retention
capacity
of
the
waste,
and
the
head
of
liquid
on
the
trench.

(c)
Liners
Comment:
All
bioreactors
must
be
built
with
two
complete
Subtitle
C
composite
liner/
leachate
collection
systems
and
with
additional
underliner
specifications.
The
commentor
notes
that
the
proposal
specified
a
design
for
Maplewood
and
King
George
that
achieves
much
more
than
other
MSWLF,
although
not
to
the
specification
recommended
by
the
commentor.

Response:
To
the
extent
the
comment
recommends
a
generally
applicable
liner
requirement
for
bioreactor
design,
it
is
beyond
the
scope
of
today's
rule.
EPA
agrees
that
the
proposed
liner
specification,
which
is
in
place
at
the
Maplewood
and
King
George
landfills
should
be
protective
of
human
health
and
environment
under
circumstances
of
liquids
addition.
During
landfill
permitting,
VADEQ
determined
that
the
design
of
the
liner
was
equivalent
to
the
composite
design
specified
in
40
CFR
Part
258.

(d)
Side
slopes
Comment:
Bioreactors
should
be
required
to
have
side
slopes
no
steeper
than
4:
1
because
the
introduction
of
liquids
significantly
increases
the
risk
of
seepages
leading
to
side
slope
failures.

Response:
To
the
extent
the
comment
recommends
a
generally
applicable
requirement
for
bioreactor
design,
it
is
beyond
the
scope
of
today's
rule.
In
both
cases
GeoSyntec
conducted
a
site
specific
slope
stability
analysis
to
determine
the
effect
of
bioreactor
operations
on
the
VA
Project
XL
Landfills.
The
slope
stability
analysis
for
the
existing
conditions
at
the
landfills
calculated
a
factor
of
safety
of
1.62
for
the
Maplewood
Landfill
and
1.
53
for
the
King
George
Landfill.
These
results
both
exceed
the
minimum
value
of
1.5
recommended
by
EPA
in
"Solid
Waste
Disposal
Facility
Criteria
Document
No.
EPA
530­
R­
93­
017,
November
1993.
GeoSyntec
also
evaluated
whether
bioreactor
operations
in
the
test
cells
would
affect
the
factor
of
safety.
In
both
landfills
GeoSyntec
concluded
the
factor
of
safety
would
remain
unchanged
by
bioreactor
operations
in
the
test
cells.
In
the
results
of
analyses
for
the
Maplewood
Landfill
GeoSyntec
concluded
the
critical
failure
surface
is
located
outside
the
anticipate
zone
that
would
be
wetted
by
liquid
application
during
recirculation
events.
The
side
slopes
adjacent
to
the
bioreactor
test
area
at
the
Maplewood
Landfill
are
4:
1
on
threes
sides
while
the
fourth
side
is
located
adjacent
to
another
cell.
The
King
George
Landfill
test
area
is
bounded
on
three
sides
by
adjacent
cells.
The
fourth
side
is
approximately
450
feet
long
and
is
adjacent
to
a
3:
1
slope.
Finally,
there
will
be
a
minimum
50
foot
setback
from
the
crest
to
the
outward
slope
for
leachate
injection
as
a
safety
measure
against
side
slope
leachate
outbreaks.
Virginia
Bioreactor
Project
XL
Landfills
­
Response
to
Comments
­
Page
14
(e)
Leachate
collection
Comment:
Problems
with
increased
biofouling,
clogging
and
siltation
can
be
expected
to
be
severe.
Increased
temperature
as
the
organic
material
at
the
bottom
of
the
waste
load
"cooks"
may
degrade
the
performance
of
the
polymer
membrane
if
leachate
pools
instead
of
being
drained
away
by
high
performance
leachate
lines.
Reliance
on
the
HELP
model
is
insufficient
for
future
decision
making.
There
should
be
enhanced
redundancy
to
cope
with
unanticipated
problems
including,
a
maximum
distance
between
lines,
a
maximum
length
of
the
lines
that
are
more
difficult
to
clean
out
when
clogged,
greater
grades
and
more
rigorous
resilience
of
the
gravel
bed
to
resist
clogging.
A
100­
foot
separation
between
lines,
1,
000
foot
line
length,
5

grade
and
gravel
not
sand
and
not
calcium­
based
gravel
for
the
drainage
bed
is
suggested.

Response:
EPA
believes
that
there
is
sufficient
information
available
to
reliably
predict
the
performance
of
the
leachate
collection
systems
that
are
subject
to
today's
rule.
There
is
a
dedicated
leachate
line
for
each
of
the
test
cells.
The
leachate
lines
are
already
in
place
and
adequate
for
the
test
at
the
site.
Leachate
lines
are
approximately
1650
feet
and
are
approximately
1500
feet
at
King
George
and
Maplewood,
respectively.
The
design
of
the
leachate
collection
system
piping
provides
for
the
pipe
to
be
embedded
in
a
high
permeability
stone
layer.
Geocloth
over
the
stone
and
the
stone
itself
distributes
the
weight
and
load.
Further
the
high
permeability
stone
acts
as
a
redundant
pathway
for
removal
of
leachate
from
the
landfill
if
the
piping
were
to
become
clogged.
There
is
also
a
second
riser
extending
from
the
primary
leachate
collection
layer
up
to
the
sump
house
building
at
both
the
King
George
and
Maplewood
Landfills.
Finally,
WM
has
stated
that
the
leachate
lines
could
be
cleaned
out
with
a
jetting
device
if
they
were
to
become
clogged.

The
cells
in
question
will
be
operated
as
anaerobic
bioreactors.
Elevated
temperatures
are
generally
not
a
problem
with
anaerobic
reactions.
Only
aerobic
processes
are
of
concern
since
they
generate
much
more
heat.
Air
is
not
being
injected
to
any
of
these
landfills
and
therefore
there
should
be
no
significant
aerobic
reactions
to
cause
major
temperature
increases.
In
addition
to
the
HELP
model,
monitoring
information
available
from
existing
landfills
operated
as
bioreactors
show
that
there
is
some
elevation
of
temperature
in
the
waste
but
only
minimally
near
the
liner.
(See
"The
Potential
Effects
of
Elevated
Bioreactor
Temperatures
on
the
Interface
Shear
Strength
of
Textured
Geomembranes
and
the
Hydraulic
Transmissivity
of
Geocomposite
Drainage
Materials,
Waste
Tech
2002,
Melody
A.
Adams,
Lance
Reed,
Nathan
Ivy,
February
2002).
In
addition,
available
information
indicates
the
waste
appears
to
be
hottest
in
its
core,
not
near
the
perimeter.
There
is
also
a
buffer
of
sand
and/
or
gravel
above
the
liners
for
additional
protection
against
elevated
temperatures.
WM
has
installed
temperature
monitoring
wells
at
three
depths
at
Maplewood
and
fourth
depths
at
King
George
in
several
locations
throughout
the
test
cells
and
the
landfills.
WM
will
be
monitoring
and
documenting
temperature
at
these
locations.
Finally,
the
FPA
provides
for
collection
of
data
on
the
temperature
of
landfill
gas.

(f)
Gas
collection
Virginia
Bioreactor
Project
XL
Landfills
­
Response
to
Comments
­
Page
15
Comment:
The
commentor
could
find
no
specification
in
the
Application
or
Final
Project
Agreement
of
how
the
gas
collection
system
would
be
constructed
to
address
gas
emissions
from
the
bioreactor
cells.
Repeated
reference
is
made
that
the
design
will
comply
with
40
CFR
part
60,
subpart
WWW.
Subpart
WWW
does
not
address
system
components
needed
to
capture
fugitive
gases
from
a
bioreactor
landfill.
This
is
totally
unacceptable.
Before
this
case
proceeds
any
further,
the
applicant
must
be
required
to
submit
as
part
of
its
proposal
detailed
plans
for
how
it
intends
to
cope
with
the
unique
gas
generation
patterns
of
a
bioreactor
in
which
the
site
is
highly
unstable,
making
pipe
and
trench
placement
extremely
difficult
and
the
rate
of
gas
generation
is
accelerated
to
a
point
in
time
when
the
geometry
of
a
landfill
creates
additional
hurdles
to
capturing
gas.

Response:
Today's
rule
does
not
address
gas
collection
because
it
is
a
site
specific
rule
under
RCRA.
Thus
this
comment
is
beyond
the
scope
of
today's
rule
making.
The
gas
collection
and
control
requirements
applicable
to
MSWLFs
(including
both
dry
tomb
and
bioreactor
land
fills)
are
regulated
under
the
Clean
Air
Act
(CAA).

With
respect
to
this
project,
the
project
sponsor
did
not
request
any
regulatory
flexibility
for
any
increased
fugitive
emissions
of
landfill
gas
that
might
result
from
the
project.
The
landfills
both
have
undergone
New
Source
Performance
Standards
(NSPS)
permitting
and
CAA
Title
V
permitting.
WM
as
the
operator
must
comply
with
all
applicable
air
regulations.
EPA
and
Virginia
Department
of
Environmental
Quality
permitting
staff
have
reviewed
this
project
and
do
not
believe
it
represents
any
increased
adverse
impact
on
human
health
or
the
environment.

As
stated
in
the
FPA,
the
surface
test
for
methane
concentration,
which
is
used
to
determine
collection
efficiency
and
surface
integrity,
will
be
conducted
according
to
the
MSW
Landfill
NSPS
surface
monitoring
requirements
set
forth
in
40
CFR
section
60.755(
c).

As
stated
in
the
FPA,
one
of
the
project
goals
is
to
minimize
landfill
gas
emissions
by
maximizing
collection
and
control
through
early
installation
and
operation
of
a
comprehensive
collection
and
control
system
in
the
bioreactor
cell.
If
odor
problems
or
air
quality
problems
occur,
then
the
system
will
be
expanded
as
needed
(e.
g.,
using
additional
extraction
wells
or
trenches
or
by
placing
less
permeable
cover
over
affected
areas).

As
stated
in
the
FPA,
one
of
the
goals
of
the
monitoring
program
is
to
monitor
the
ground
surface
of
the
entire
site,
including
the
liquid
application
area,
for
the
presence
of
landfill
gasses
(i.
e.
methane,
NMOCs,
etc.,)
to
ensure
that
permit
and
regulatory
limits
are
not
exceeded,
and
evaluate
the
need
for
additional
landfill
gas
collection
components
(i.
e.,
wells
and
header
pipe)
during
liquid
application
events
to
improve
the
effectiveness
of
the
landfill
gas
collection
system.
(see
section
3.
1.
2.
4
Potential
Environmental
Impact
to
Air)

As
stated
in
the
rule,
effective
November
1999,
Waste
Management
installed,
and
is
operating,
an
active
(i.
e.
vacuum
induced)
landfill
gas
collection
system
in
Phases
1,
2
and
3
at
the
Maplewood
Landfill.
An
active
gas
collection
system
became
operational
at
the
King
George
Landfill
on
Virginia
Bioreactor
Project
XL
Landfills
­
Response
to
Comments
­
Page
16
December
10,
2000.
In
addition,
on
September
1,
2001
Waste
Management
signed
an
agreement
with
a
private
energy
development
company
to
construct
a
9MW
power
plant
fueled
by
landfill
gas
at
the
Maplewood
Landfill.
This
plant
is
currently
beneficially
reusing
the
landfill
gas
to
generate
energy.
Waste
Management
is
currently
negotiating
a
similar
gas/
energy
recovery
agreement
for
the
King
George
Landfill.

(g)
Buffer
Zones
Comment:
Buffer
zone
are
needed
to
keep
liquids
away
from
side
walls
in
order
to
avoid
seepage
that
can
lead
to
a
side
wall
failure.
The
commentor
did
not
see
a
discussion
of
buffer
zones
or
how
liquid
addition
would
be
managed
to
prevent
leakage
into
the
buffer.

Response:
Buffer
zones
for
the
side
slopes
are
discussed
in
the
FPA.
The
FPA
states
that
in
order
to
minimize
the
potential
for
the
occurrence
of
seeps,
liquid
distribution
structures
will
be
placed
at
least
50
feet
away
from
the
crests
of
outward
slopes.
The
FPA
also
states
that
the
potential
impacts
that
could
be
caused
by
seeps
are
and
will
continue
to
be
promptly
mitigated
at
the
Maplewood
and
King
George
County
Landfills
through
a
program
of
seep
detection
through
visual
inspections
and
of
maintenance
to
quickly
repair
any
seep
that
would
occur.
The
leachate
distribution
pipes
will
be
installed
along
contour
lines
or
perpendicular
to
the
slope.
WM
agreed
to
monitor
the
liquid
levels
in
the
landfill
gas
extraction
wells
during
the
project
as
an
additional
safe
guard
against
liquid
buildup
in
the
landfill
and
the
possibility
of
surface
seeps.
WM
also
will
be
monitoring
gas
production.
If
liquid
levels
were
to
rise
into
the
gas
extraction
wells
this
could
lower
the
production
of
landfill
gas.
This
program
of
inspections
and
maintenance
will
continue
to
be
implemented
throughout
the
XL
Project.
Further,
because
of
the
ongoing
project,
site
personnel
will
be
particularly
advised
to
be
more
sensitive
to
the
potential
for
seeps.
At
King
George
only
the
south
side
of
the
test
area
is
directly
adjacent
to
a
side
slope,
the
other
three
sides
are
adjacent
to
other
cells
of
the
landfill.

(h)
Final
flush
Comment:
Before
final
cap
is
placed
on
the
cell,
clean
water
should
be
flushed
through
the
site
to
leach
out
hazardous
compounds.

Response:
As
stated
in
proposed
rule,
at
the
end
of
the
project
term
the
VA
Project
XL
Landfills
must
return
to
compliance
with
the
regulatory
requirements
which
would
have
been
in
effect
absent
the
flexibility
provided
through
the
site
specific
rule.
As
explained
in
the
preamble
of
the
proposed
rule,
research
reported
in,
"Active
Municipal
Waste
Landfill
Operations:
A
Biochemical
Reactor,"
Reinhart,
1995
(Reinhart
1995),
has
shown
that
bioreactor
processes
tend
to
reduce
the
concentration
of
many
pollutants
in
leachate,
including
organic
acids
and
other
soluble
organic
pollutants.
Bioreactor
operations
brings
pH
to
near­
neutral
conditions
and
generally,
metals
are
much
less
mobile
under
these
condition.
The
Reinhart
1995
study
found
that
metals
were
largely
precipitated
and
immobilized
in
the
waste
of
bioreactor
landfills.
Upon
completion
of
the
Project
term,
the
liquid
addition
to
the
bioreactor
test
cells
will
be
stopped
and
Virginia
Bioreactor
Project
XL
Landfills
­
Response
to
Comments
­
Page
17
the
leachate
will
be
drained
and
the
head
on
the
liner
will
continue
to
be
maintained
as
specified
by
standard
RCRA
Subtitle
D
landfill
regulations.

III
Proposed
Changes
in
Bioreactor
Tests
14.
Comment
Summary:
Stabilization
(pages
24­
27)

To
determine
whether
a
waste
load
has
been
stabilized
such
that
the
post­
closure
period
might
be
reduced
requires
a
reliable
measurement
of
how
much
organic
material
remains
undecomposed
at
closure.
This
requires
statistical
sampling
techniques,
and
then
reliable
measures
of
remaining
carbon
values
and
of
the
rate
of
decomposition.
The
commentor
stated
its
view
of
what
constitutes
reliable
statistical
sampling
for
the
purpose
of
measuring
waste
stabilization.

Response:
The
comment
is
beyond
the
scope
of
today's
rulemaking.
There
is
nothing
in
the
proposed
rule
or
today's
final
rule
that
would
shorten
or
reduce
the
post­
closure
period.
Moreover,
the
comment
concerns
the
FPA,
which
the
commentor
did
not
comment
on
when
the
Agency
announced
the
availability
of
the
draft
FPA
and
solicited
public
comments.
The
FPA
provides
for
annual
testing
of
solid
waste
stabilization
and
decomposition
by
the
collection
of
4
test
borings
per
year
with
3
samples
per
boring.
The
samples
will
be
collected
from
approximately
5
­
10
ft.,
25
­
30
ft:,
45
­
50
ft.
and
analyzed
for
moisture
content,
biochemical
methane
potential,
cellulose,
lignin,
hemi­
cellulose,
volatile
solids
and
pH.

15.
Comment
Summary:
Gas
Collection
(pages
28­
29)

The
FPA
relies
on
measurements
of
fugitive
gas
emissions
pursuant
to
40
CFR
part
60,
subpart
WWW,
but
that
rule
only
requires
limited
measurement
of
the
concentration
of
select
compounds
in
grab
samples.
Measurements
of
the
total
quantity
of
methane
emissions
are
needed,
not
just
concentration
levels.
Measurements
are
also
essential
to
determine
the
collection
efficiency
of
the
gas
extraction
systems
for
estimating
landfills'
contributions
to
global
warming.

The
study
by
SCS
Engineers
contains
no
empirical
data
to
support
a
claim
of
enhanced
gas
collection
performance
of
bioreactors,
but
rather
is
purely
hypothetical
in
which
the
authors
assume
that
bioreactor
gas
collection
is
more
efficient.

The
commentor
recommended
that
same
statistical
sampling
techniques
it
recommended
for
stabilization
tests
(see
p.
25)
should
be
used
to
determine
how
many
samples
are
necessary
and
which
part
of
the
landfill
face
to
sample,
but
specified
the
following
differences:

(1)
The
additional
separation
of
the
waste
load
by
vertical
strata
is
unnecessary,
(2)
The
importance
of
including
the
exposed
side
walls
as
well
as
the
working
face
in
the
array
from
which
samples
are
pulled
is
absolutely
essential;
and
(3)
Samples
should
be
pulled
during
each
season
of
the
year
on
a
day
selected
randomly.
Virginia
Bioreactor
Project
XL
Landfills
­
Response
to
Comments
­
Page
18
The
commentor
also
recommended
that
if
a
cylindrical
polypropylene
enclosure
is
placed
on
the
ground
surface
and
a
small
amount
of
surrounding
dirt
is
used
to
provide
a
seal,
with
a
batteryoperated
fan
within
the
enclosure,
samples
can
be
collected
from
within
the
head
space.

Response:
The
comment
is
beyond
the
scope
of
today's
rulemaking.
As
the
commentor
notes,
requirements
concerning
landfill
gas
collection
and
control
are
contained
in
Clean
Air
regulations.
These
regulatory
requirements
are
implemented
through
VADEQ
permits.
However,
as
part
of
the
XL
Project
studies
agreed
to
in
the
Final
Project
Agreement,
Waste
Management
will
measure
the
flow
rate
of
landfill
gas
to
determine
the
quantity
of
gas
generated,
measure
emissions
of
releases
of
landfill
gas,
in
order
to
verify
that
permit­
specified
air
quality
standards
are
not
being
exceeded,
and
track
the
frequency
of
any
odor
complaints
during
and
after
liquid
application
events.

For
the
first
year,
tests
will
be
done
quarterly
and
for
the
following
years
some
test
frequencies
will
be
changed
to
semi­
annually
or
as
otherwise
required
in
the
FESOP
with
the
VADEQ
for
early
gas
collection,
control,
and
monitoring.

Details
on
this
measuring
and
the
LF
gas
extraction
system
are
contained
in
the
monitoring
plan
in
the
NSPS
permits
for
the
landfills.
There
is
active
gas
collection
at
both
Project
XL
Landfills.
WM
is
currently
beneficially
reusing
the
LF
gas
at
the
Maplewood
LF.
WM
is
working
toward
the
beneficial
reuse
of
the
methane
at
the
King
George
LF.

The
FPA
outlines
the
goals
for
the
monitoring
system
which
include
the
monitoring
of
the
ground
surface
of
the
entire
site,
including
the
liquid
application
area,
for
the
presence
of
landfill
gasses
(i.
e.
methane,
NMOCs,
etc.,)
to
ensure
that
permit
and
regulatory
limits
are
not
exceeded,
and
evaluate
the
need
for
additional
landfill
gas
collection
components
(i.
e.,
wells
and
header
pipe)
during
liquid
application
events
to
improve
the
effectiveness
of
the
landfill
gas
collection
system.
The
surface
test
for
methane
concentration
which
is
used
to
determine
collection
efficiency
and
surface
integrity
will
be
conducted
according
to
NSPS
surface
monitoring
requirements
in
40
CFR
section
60.755
(c).

The
surface
test
for
methane
concentration
which
is
used
to
determine
collection
efficiency
and
surface
integrity
will
be
conducted
according
to
NSPS
surface
monitoring
requirements
in
40
CFR
section
60.755
(c).

16.
Comment
Summary:
Leachate
Collection
Line
(page
30)

The
commentor
stated
that
the
ability
to
maintain
leachate
collection
lines
in
dry
tomb
landfills
has
not
been
scientifically
qualified
and
is
a
serious
cause
of
concern,
which
is
greater
in
bioreactor
landfills
due
to
increased
problems
of
siltation,
clogging
and
biofouling.
A
key
test
to
evaluate
whether
the
performance
of
these
lines
may
be
compromised
is
to
use
an
in­
line
camera
along
with
the
clean
out
head
annually
in
the
test
and
control
cells.
Virginia
Bioreactor
Project
XL
Landfills
­
Response
to
Comments
­
Page
19
Response:
Today's
rule
requires
that
the
leachate
collection
system
shall
be
operated,
monitored
and
maintained
to
ensure
that
less
than
30
cm
depth
of
leachate
is
maintained
over
the
liner.
The
rule
also
requires
the
operator
to
collect
monthly
sampling
of
the
leachate;
determine
on
a
semiannual
basis
the
total
quantity
of
leachate
collected
in
test
and
control
areas;
the
total
quantity
of
liquids
applied
in
the
test
areas
and
determination
of
any
changes
in
this
quantity
over
time;
the
total
quantity
of
leachate
in
on­
site
storage
structures
and
any
leachate
taken
for
offsite
disposal.
The
collection
of
this
information
will
provide
sufficient
information
to
be
able
to
evaluate
how
well
the
leachate
collection
system
is
performing.
Although
a
leachate
line
visual
inspection
using
an
in­
line
camera
is
one
way
of
assessing
the
performance
of
the
leachate
collection
lines,
EPA
does
not
agree
that
this
test
should
be
required
as
part
of
today's
rule.
GeoSyntec
performed
a
leachate
pipe
strength
calculation
as
part
of
the
evaluation
of
the
landfill
leachate
system.
See
response
to
Comment
13
(e)
above.

Conclusion
17.
Comment
Summary:
The
FPA
does
not
resolve
key
issues
regarding
development
of
bioreactor
designs,
foremost
of
which
is
the
assumption
that
performance
equal
to
dry
tomb
landfills
constitutes
superior
performance
and
that
economics
takes
priority
over
the
environmental.
Greater
scientific
rigor
is
needed
in
several
tests
in
order
to
produce
reliable
data.
The
commentor
does
not
believe
that
the
rulemaking
should
go
forward
until
the
signification
deficiencies
identified
are
corrected.
Economic
considerations
and
pressures
should
not
deter
EPA
from
making
the
necessary
corrections.

Response:
EPA
appreciates
that
the
commentor
has
serious
reservations
regarding
bioreactor
landfill
technology
in
general
and
is
concerned
in
particular
about
design
criteria
for
bioreactor
landfills.
However,
today's
rulemaking
does
not
concern
design
criteria
for
bioreactors,
rather
it
concerns
site­
specific
requirements
for
operation
of
existing
landfill
cells
as
bioreactors
for
a
finite
period
of
time.
EPA
does
not
agree
that
today's
rule
or
the
XL
project
that
it
addresses
prioritized
economics
over
the
environment.
As
set
forth
in
the
FPA
and
guidelines
for
Project
XL,
superior
environmental
performance
means
environmental
performance
that
is
superior
to
what
would
be
achieved
through
compliance
with
current
and
reasonably
anticipated
future
regulations.
The
agency
does
not
agree
with
the
statement
that,
"performance
equal
to
dry
tomb
landfills
constitutes
superior
performance"
but
rather
believes
bioreactors
have
the
potential
to
provide
superior
performance
as
stated
in
the
Rule
and
FPA.