ILLINOIS POLLUTION CONTROL BOARD
February
~0,
1985
IN THE MATTER OF:
PROPOSAL OF THE ILLINOIS POWER
R83-1.
COMPANY FOR A
SITE~SPECIFIC
EFFLUENT RULE CHANGE
(PROPOSED
AMENDMENT TO ILL. ADM.
CODE,
TITLE 35, PART 304~STJ~PART
B~
ADOPTED RULE.
OPINION AND ORDER ~
BOARD
(By B~Forcade):
This matter c~
3efore th~Board on
Illinois Power
Company~s(~IPC~) ~
filed May 17, 1983,
to amend the
Board’s Water Po1iu~
Regulations by adding a new
Section
304.209.
Under
the
....
:.posed s~te~speeific
effluent rule change,
the effluent limitat
on the discharge of
total suspended
solids
(“TSS”)
from
ash pond system of IPC’s Wood
River
Station in East A1to~ Illinois,
into Wood
River Creek would be
raised from 15 milii~~msper liter
(mg/I)
to 30
mg/.
as an
average of daily valuas for thirty consecutive
days, and from 30
mg/i
to 100 mg/i as a maximum for one day.
(See:..
Exhibit.).
On April 27,
1984, the Board adopted for
first notice a new
§304.209 to
Subpart B of Part 304 of Title 35 of
the Illinois
Administrative Code,
This new
section
would
provide eite—
specific relief to IPC for their Wood River
Station.
First
noticeof this propo~a1was
pubi ~ad
Ot
8 Iii.
Reg.
8116, on
June
8, 1984
Lro~~vrs
~
~
first
notice,
the
applicable TSS effI~ntlimitati~vafor the
facility’s ash pond
system effluent woald. ce 30 mg/I
average
of daily values
for thirty consecutive days and
~Gt
2rcJ/~.
as
a daily maximum.
Comments
were
received, during the first notice
period,
from the
Illinois
Environmental
Protection !rqency
(“Agency”)
and from
IPC.
The Administrative Code Unit
thrritted
a
comment on June
11,
1984, concerning
the lilirtoir Register first
notice format.
In response to the Agency~rconnients during
first notice and
on reexamination of
the record~ tI::~e Board
changed the proposed
rule by reducing the daily maxinow iron 100
mg/i to 50 mg/i.
By
Order
of the Board, dated Octoba:
12,.
1984,
the proposed rule, as
modified, was submitted to the Joint COmmittee
on Administrative
The
Board wishes
to acknowledge
the
contributions of David
G
Mueller
who
was
r
as5lstant
for this
rulemaking
63~
118
Rules (~JCAR~).~R~R ~
~L~:c;~J
r~t~
~e review
commenced on
November
5,
1984
2AR ~r~e~eda Jartification
of No Objection to
this rulemaking ~
Jecea.oer 11, f9~~ending
the second notice
period.
The TSS staa~arde~opcsed’b$
122 are the
same as suggested
by
the United St~~s
Enviton;ieotrif
atotection
Agency
(“USEPA”)
for the electric on~ergeneraling g~intsource
category as set
forth
in 47 Fed~!R~i~.
522~0
(cvenbrr
19,
1983)
(to be codified
in 40 C.F.R.
Par~.
423)~.
Tie
trone~believes
that the Federal
effluent standard ~f 30
iig/1
:s
no~eappropriate
in the instant
situation because
i~
was tntenlionaLiv established
by the USEPA
as being
the beer cr’rc,ticahie
creatr,enr currently
available
for
one
specific md ‘c~rry—tbe~taainelectric
industry.
(R.
137—
138).
The Petit~cnerassorts that the (JSEPA
set the Federal
effluent limits ~isr
car~’fu~Iy
ec~n~uating
the
fuel.
types,
equip-
ment,
age and
si~
c2
~1e~rnii
pL~tnt~,water
usage, ~nd
wastewater
constit’nnts
rnici~ed
ir,
ftc
steam
electr4c
cost
of
control
and
treatnecr
tech~oIogies
aun liable
for
potential
use
in
this
particular
i~2~rrc’
(R~
~~1G;
R~ 156—162).
Accordingly,
IPC
regces~log
‘~~211
be
granted
a
site—specific
relaxation
of
the
ecet~
~
~t~nR~rd
to
the
same
level
as
the
Federal standards
~Jo.
0io~i~tt5~
Two
hear ings
cc
~.
~.
regulatory
proposal were
conducted.
The
f1rr~
:c
r
~.
~‘.
held
on
August
22,
1983,
in
Altori,
I11inois~
‘
‘.
‘.
took
place on August
26,
1983,
in
Chicago,
~‘
‘I;
~.
the
public were present
at
both
hearings;
jc.:
,
;‘
~d,
and
nine exhibits were
admitted
into
evid~
At these hear
~,,
~ttempted
to demonstrate
that
it has been
~
~~v~ting
statewide non—
industry
specific
.
~j/1
as
set forth
in 35
Ill, Adm,
Code
30
.~.
,
~nta11ation
of
numerous
control measures~
~
,
~.
‘~ieonly
economically
feas-
ible physiochemica
~
.
.‘
~
facility
would
cost
$3.9
million to install
,
.
to
operate and
maintain.
(R.
35
‘.~
1’
.
a
F).
The company ‘cc~
;~acility
would deprive
Wood River Creek of
~.;
~.
.
-.
~~ton and
adversely affect
the propagation ar
.
‘~
~i1e
fish
from the
new’ ash
pond
system by deC
1
~“
~
vital
breeding ground.
An
engineering St
‘
‘
~..
.
was
proffered
to
demon-
strate that the p
~
“.
~
system
is
the
least
costly alternative
~
~
hieve
compliance with the
existing 15 mg/i $~
The Director
~
~cent
of
Energy and Natural
Resources
(~‘DENR’~adr~$
1n December
6,
1983,
that
the
DENR
had
made
.~
fOr
:.
c.
~omic
impact
study
on
the
regulatory
propoe-~
~
2fOfO1
is
rrfO
~eceesary.
At its December
13,
1983 meeting
rr ~‘~cic’r~ard
~-r~rcical
Advisory Committee
3
(“ETAC’~) concurred
in
the
DENR~s finding.
IPC owns and operates a steam—electric
generating plant
in
East Aiton, Illinois, which discharges effluent
pursuant to NPDES
Permit NO.
IL00007O1.
(R. 123—131; see:
Exhibits
6,
7 and
8).
The Petitioner’s plant,
which
is known as
the Wood River Station
(“Station”),
includes two large coa1~fired
electric generating
units which~provide77
of the facility’s
maximum capacity to
generate el~tricity, and three smaller units
which burn oil or
natural gas.
CR.
14).
In
the
two
coai~fired
units, bottom ash
and fly ash are
(1)
produced no
by”~products
of coal combustion;
(2)
removed from the
units by o’~~c~
~“dLng
with water withdrawn from
the Mississippi
River;
(3)
rcrnsported by the sluice to an
ash pond system;
and
(4)
deposirod ~inthe ash pond system.
(R,
14—15),
TSS are first
removed frcno~,ihewater which is channeled
into the ash pond
system.
Thnr~cater
is released from the ash
pond system, which
serves
as
Icaf:
of
the
Station’s pollution control
equipment, and
subsequentlo discharged
through an earthen
conveyance into an
unnamed
tribc~t~ary
of Wood River Creek,
which
flows into Wood
River Creek
and
then
to the Mississippi
River.
During the
twelve~-monthperiod ending on December 31,
1982, effluent flows
from the ash pond system averaged 2.74
million gallons per day
(mgd)
and
ranged
from 0.45 mgd to 5.10 mgd.
CR.
14—15).
Bottom ash and
fly ash were
sluiced
from the two coal—fired
units
into an older ash pond system
(Old Ash
Pond System)
before
the
completion and utilization of IPC’s
New Ash Pond System.
CR.
16).
Because of its many years of service,
the Old Ash Pond
System had become nearly filled with ash by
1977,
and dredging
was necessary
to
keep
it operative.
Additionally,
the concentra-
tion of TSS
in
the
effluent
from
the
Old
Ash Pond
System would
sporadically
exceed
the
15
mg/I
limit
for
TSS
delineated in 35
Ill, Adm, Code 304.124(a),
(R, 16),
To
avoid
the
necessity
of
continual
dredging
operations and
to
reduce
TSS
excursions,
IPC
applied
to the
Agency and to the
U.S.
Army
Corps
of
Engineers
for
the
requisite
construction
permits
to
build
the
New
Ash
pond
System
early in 1977.
(R.
16—
17).
On
May’17,
1977,
the
Agency
approved
IPC’s
construction
request.
Similarly,
in
December
of
1977,
the Corps
of Engineers
issued
IPC
a
construction
permit.
(R.
17).
Construction of
the
New
Ash
Pond
System
began
in
June
of
1978 and
was
completed on
September
29, 1979.
(R, 17—18).
Discharge
of water sluiced from
the
two coa1~firedunits first began from
the New Ash Pond System
on
February 22,
1980.
CR. l8~~l9).
Subsequently,
in May of
1981,
the
Agency
permitted
IPC by
permit modification approval for the rerouting of
overflow water
from
the
ash
hopper
boiler blowdown water, certain
water
treatment
plant
wastes,
and
demineralizer
regenerate wastes
to
the
New
Ash
Pond
System,
On
November
6,
1981,
the rerouting
of
these
waters
and
wastes
into
the
New
Ash Pond System was
63420
4
completed.
While
the
New
Ash
Pond System was under construction during
the
interim
time
period
between
June,
1978 and September,
1979,
the
Petitioner
tried
to
control the
TSS levels
in its effluent
by
undertaking various measures
such as
(1)
adding a
polymer to
the
sluice water
so that suspended solids might settle more rapidly;
(2)
installing
gravel
near the outfall to reduce ash resuspension
brought
about
by
the
action of the wind and waves;
(3) installat-
ion of utility poles
in front of the overflow weir to combat
wave
action;
(4)
designing
new skimmers for the existing pond
outfalls;
and
(5)
testing
to see what further actions would be
helpful.
CR,
17—19),
After construction of the New Ash Pond
System was completed
on
September
29, 1979,
the Petitioner capped
the old
ash
pond
on
October
25, 1979.
(R.
18),
The
New
Ash
Pond
System which is currently in use at IPC’s
generating
station
consists of three interconnected compartments
which
are
operated
in
series.
CR. 15),
Initially, water
is
passed
into
the
first
compartment which has a surface area of 66
acres
and
a
design
volume of 539 acre—feet,
This water
is next
channeled
into
a
smaller,
second compartment which has a surface
area
of
5,2
acres
and
a design volume of 16 acre—feet,
The water
then
flows
into
a third compartment which
is smaller
than
the
other
two
ponds
and
has a surface area of 4.7 acres and a design
volume of 14 acre—feet,
CR.
15—16),
Mr. Thomas B. Davis,
P.E,,
the supervisor
of water quality
for IPC~sWood River Station, testified extensively on
behalf of
the
proponent.
(R. 9—36;
R. 122—155;
see:
Exhibit 2).
In
reference
to
various
tables
in Exhibit B indicating
the monthly
average
and
daily
maximum
TSS concentration values of the
effluent
from
both
the
old and new ash pond systems during the
time
period
from
January,
1976,
to June,
1983, Mr. Davis
indicated
that
(1)
60
(24
of
40)
of the monthly average effluent
TSS
concentration
values
from the New Ash Pond System exceeded
15.0
mg/I
and
12.5
(5
of
40) were also greater than 30 mg/i;
(2)
85
(34
of
40) were
also
greater
than 30.0 mg/i;
(3)
only one
daily
maximum
TSS
value
exceeded 100,0 mg/i and this occurred
in
April,
1980;
and
(4)
these
percentages are comparable with the
Old
Ash
Pond
System.
CR.
18—20;
see:
Exhibit B and Exhibit
9).
Mr.
James
A. Smithson, a certified fishery scientist who is
presently the supervisor of field biology for IPC, testified
about the biological monitoring,
testing, and treatment programs
conducted at the Petitioner’s facility.
CR,
37—107;
R. 156—162;
see:
Exhibit
3),
Mr.
Smithson stated that,
although water
quality in
the
New
Ash Pond System has promoted the development
of
a diverse
fish
community,
“the use of green sunfish and large—
mouth bass
in
the
second and third ponds has genera1l~’prevented
the
populations
of
bottom
dwelling species from becoming abundant
enough
to
cause
a
major
elevation in TSS.”
(R,
44).
Mr.
Smithson
noted
that,
even though the TSS
in the effluent
63~121
5
from the New Ash Pond System
often
has
exceeded the 15 mg/i
level,
a diverse aquatic
community
has
thrived over the last
three years
in the New Ash Pond
System
and
in the ditch running
from it to the Wood River Creek.
(R.
45).
After conducting an
in—depth biological survey in July, 1982
to
examine the aquatic
communities existing
in the New Ash
Pond
System,
Mr. Smithson
determined
that the system
was
analogous to
an
“artifical back water
area”
where Mississippi River water with
a high TSS
is used to move ash into a retention area
and the ash
and
silt then settle out,
(R.
59—62).
~onsequentiy,
the
phytoplankton thrive
due
to
the
increased
addition
of
nutrients
and
improved water clarity.
The
flourishing phytoplankton in
turn provide
the primary energy
source
for the rest
of
the aquatic community.
(R,
61),
Juvenile
fish, which are
produced
and
thrive
in
the New Ash Pond
System,
can
escape through the discharge
pipe
and
enter the ditch
running
from the system and eventually
reach
Wood
River Creek and the
Mississippi River,
CR, 61),
Thus,
“the
very
richness of
the aquatic
community in the New
Ash
Pond System has helped to
create
a situation where the
System’s effluent cannot meet the
present
limit for TSS set in
the
Board rules,”
CR.
63).
Accordingly,
Mr.
Smithson concluded
that
“the biological community
in the receiving
waters would
benefit more
from the
biological contributions from the New Ash
Pond
System
as
they
currently exist than from receiving water
which
has been treated and
filtered
to reduce the TSS below
fifteen milligrams per liter,”
(R,
63—64),
During the time period
between April
of 1980
and September
of
1982,
IPC spend over $125,169 on corrective measures to
reduce
the TSS levels
in effluents from its New Ash Pond System.
Bowever, all
such
corrective actions have proved futile,
(R.
31;
R.
34—35;
see:
Exhibits
E
& F),
The seven major factors
which
possibly have
been
contributing
to high concentrations
of
TSS
in
IPC’s effluent include
(1) berm
damage
caused by burrowing
muskrats;
(2)
feeding activities of bottom fish;
(3)
floating
fly
ash and waves;
(4) wind and wave action causing bank erosion
and
ash resuspension;
(5)
dramatic increases in the abundance of
one
or more algal species
(i.e.,
“algal bloom”);
(6) non—uniform
distribution of influent flow through the basin
(i.e.,
“short—
circuiting”)
and
(7)
insufficient hydraulic detention time in
the
basin which limits the amount
of suspended
solids which
can
settle out of suspension.
CR,
30—31).
Although
the
Petitioner
has
taken various steps
to
lessen the effects
of these seven
primary
contributing factors
to the TSS problem,
it has not
been
able
to substantially reduce the
total
levels of TSS
in effluent
from its New Ash Pond System.
To alleviate the berm damage caused by the burrowing
activities of muskrats, IPC trapped these muskrats during the
winters of 1980 and 1981,
The Petitioner has also attempted to
63-122
6
limit
the
possible
effects
of the feeding activities of bottom
fish
by
conducting
fish
eradications and by adding several
hundred
green
sunfish,
a
natural predator,
to aggressively feed
upon
the eggs,
fry,
and
young
bottom—dwelling
fish,
CR, 32—33;
R.
42)
To lessen
the
possible
effects of floating fly
ash
and
waves,
IPC has
(1)
installed boards around
the skimmers
in the
first and
second
compartments of the New Ash Pond System in
October of
1980;
(2)
located a
diagonal
row of floating utility
poles
in the second
and: third
compartments
of the New Ash Pond
System
in July of 19Sf;
and
(3)
installed floating utility poles
near
the outfall of
‘i”:kor
first
compartment
of the New Ash Pond
System
in
September
oftOOl.
(R.
32).
To reduce the effects of
wind
and waves,
along
of
tb the àoncomitant effects of bank
erosion and
ash
resus’gcnoion,
rip—rap was placed along the banks
in
the
first compartmo:I
(reduce shoreline erosi~) during June,
1981 and additionally atility poles were installè~in rows across
the surface of the third compartment
to
combat wave action,
CR,
32)
Additionally,
IPC considered using an aigicide or biocide to
control algal blooms,
These blooms, which fregqitly result
in
decreased water transparency and a
visible
laye~f algae
at
the
surface,
contribute to
the
volatile
organic
port~nsof TSS,
Rowever,
this control measure
was not
implemented because it
would
not reduce any of the
non—volatile inorganic
portions of
TSS.
Moreover,
its long—term
use would have
a detrimental effect
on
the
biological communities in the
New
Ash Pond System and
in
waters receiving effluent from the ash pond.
CR,
34;
R, 44—45).
Moreover,
a
forty—five
degree diversionary elbow was
installed in
July,
1981,
on
the
inlet pipe to the second compart-
ment
in
an
attempt
to
riiduce
the
possible effects
of
short—circu-
iting.
(R, 33),
Howev4’Pr,
on August 31,
1982, and September
1,
1981,
IPC
conducted
a
dye~tracer
study of the
flow
patterns
in
each
compartment
which
showed
that the influent was not short—
circuiting.
CR.
33—34),
Similarly, 1PC’s evaluation of the theoretical and actual
hydraulic retention times of the New Ash Pond System concluded
that the 67—day retention time was adequate’ and was not
responsible for
the
high
concentrations of TSS,
(R,
33—34),
IPC has maintained
that, although the studies and corrective
measures that it implemented have resulted
in increased control
over
some of the possible sources of TSS,
its expenditures of
$125,169 and the efforts to bring the concentration levels of TSS
‘in the effluent from the New Ash Pond System into consistent
compliance with the
15 mg/i standard of Section 304,124(a)
have
not been successful,
(R,
34—35),
According to IPC,
the only other possible corrective action
which could offer reliable assurance of the reduction of TSS i~
63.123
7
the
effluent
I
r
che
New
Ash Pond System
to
meet
the
15
mg/i
limit would
tcaatment by means of a physiochemical wastewater
treatment
plani.
hat chemical coagulation,
flocculation,
and
precipitation
.lowed by filtration could occur.
However,
IPC
has
asserted
t~a
a
oh
a facility would prove
effective
only at
the
cost
of
a
umber
of
adverse economic and
environmental
effects.
(H
35~3
IPC has estimated that
the
installation
of
the
physiochemca
astewater treatment facility wdtl cost appro-
ximately $3,90
n capital expenditures plus $145,000 per
year for
operti
r
maintenance and chemicals.
(H
35—36),
In
ad~
~be
high
capital and
ma~nte~iancecosts
of
physiochemic
eater
treatment,
IPC believes
that
treatment
of
the high
TSS
in
the
New Ash Pond
System
by
the
use of
chemicals,
a
a ical filtration would deprive the receiving
waters of
the
~ry energy subsidy” from the phytoplankton and
of
the recrui
o~.
juvenile fish fro~theNew Ash Pond
System.
(H,
IPC has
r
catred that the New Ash Pond System
is
ecologic-
ally
important
case it currently serves as
a spawning and
rearing
area
(~
rnurseryn)
for various speci~sof fish and is
an
abundant
soc
of
phytoplankton.
CR.
46; H.
50—60;
H.
61—
62),
Phytoplan
)r,
the
passively floating
plant
life
t
a
body
of water,
acts
a primary energy
source
for
tne
curio
nding
aquatic
ecosyste
aid
provides
foods and
energy
for
growth
and
development
of aquatic life.
CR.
67).
Because
Wood
River
Creek,
which
receives
the
effluent from the New Ash
Pond
System,
is
very
limited in its
natural
ability to maintain its own biological
and
aquatic commun
,
the
juvenile fish and phytoplankton produced
in
the New A’f
‘
S
a
em
greatly
contribute
to
the
aquatic
life
in the
creek.
;
H. 61—62;
R.
68;
see:
Exhibit
4).
Concomitant~
ase
in the abundance of phytoplank~ton
also is
a co
a factor in the increase in the volatile, or
organic,
po~
185
~.n
the
New
Ash
Pond
Sy~~tem
(H,
62—
63)
The Petit
las also indicated that its utilization of
green sunfis~a
gemouth bass as biological controls
in the
New
Ash
Pond
3
~.
a s
provided
Wood River Creek and Lhe Missi-
ssippi
River
w’t
i
additional source of these
important
game
fish,
CR.
44,
Additional~
PC emphasized that its New Ash Pond System
provides a
mocha
ci.
for withdrawing water from the Mississippi
River
which
is
i
ga
in TSS and holding the water
for
a while so
that
silt is set’
ad out and nutrients
in the water can be
utilized
by the
patio organisms in the ash pond.
When water
is
discharged
to
tI~
warned
tributary
of Wood
River
Creek,
juvenile
fish,
phytoplan
and
other
organisms
leave
th~ ash
pond
system and
even,
enter
Wood
River
Creek
a
d
the
Mississippi
River,
Accor
‘
IPC argues
that treatment of tie TSS
in the
New
Ash Pond
,
by the use of chemicals ard mechanical
filtration
.~
,
‘;ve
the
receiving
waters
of
the
primary
63-124
8
energy subsidy
from the
phytoplankton and the recruitment of
juvenile fish
from the
New Ash Pond System.
(R.
83;
R.
98—
101).
Conversely, IPC contends that the discharge of effluent
containing
30
mg/I of
TSS would have no adverse effect on the
aquatic community
in
Wood River Creek.
CR.
36—37;
R. 45—46;
R.
63)
IPC has
noted that it
must currently comply
with
the general
TSS standard of
15
mg/i
set forth in 35 Iii. Adm, code 304.123(a)
which applies
statewide
to
all types of industry and facilities
without making
any
realistic
distinction as to variations which
may occur
in
the technologies
employed or
in existing
physical
conditions.
(See:
January 6,
1972
Opinion
of the Pollution
Control
Board
in R70—8).
Thus,
IPC
believes
that the
Federal
effluent
limitation
is
more apropos
to conditions experienced by
electric
utilities
and
more relevant
to the control and treatment
technologies
which are
effective and available to
the
Station
than
is
the
limitation
contained
in
Section
304,124(a),
(R,
137—
140);
R,
156—162;
see:
Exhibit
5;
39
Fed.
Reg.
36,
186
(October
8,
1974);
45
Fed,
Reg.
68,
331
(October
14,
1980))
Moreover, IPC
feels
that
the
data used
to
develop
the
Federal
effluent
standard
is
more
representative
than
the
historical
data
on
TSS
compiled
from
pollution
control
equipment
at
the
Station
over
a
relatively
short
four
year
period,
since
the
Federal
standard
represents
an
across—the—board
evaluation
of
data
from
many
sources
throughout
the country over
the
life
of
multifaceted
control
equipment.
(R.
139—140;
R.
142—163)
In its written comment of January 10,
1984, the Agency did
not
dispute the basic facts presented by the Petitioner and did
not
disagree with
IPC’s
cost estimates,
The Agency also
concluded
that
“the effluent
from outfall 002 of the new ash pond
does not appear
to
be
having a
deleterious
effect on the
aquatic
life
of the
receiving
stream.”
(Agency Comment p.
1).
Although
the
Agency
has
endorsed the 30—day average effluent
limit of 30
mg/l
of
TSS
as
being appropriate,
the Agency has
advocated that
the
daily
maximum effluent limit for TSS
applicable
to
IPC’s
Station
should be
50 mg/i,
rather than the
requested
Federal
standard
of
100
mg/i.
(Agency
Comment
p.
3).
Although some
daily
maximum
concentrations
of TSS
in
excess of
50
mg/i
occurred
at
IPC’s facilities, the Agency notes that these
excursions
happened before
“final control measures” were taken in
March, 1982
and
the Agency
believes
that
a 50 mg/I daily
maximum
eUluent
standard
for TSS will
be
adequate
to allow IPC
to
continue
operations without
requiring
further
treatment,
(Agency
Comment p.
3).
On the
other
hand,
IPC
has contended
in
its Second
Written
Submission
filed
on
January 20,
1984,
that
the evidence
presented
at the hearings
indicates
that
the daily
maximum effluent limit
on TSS should
be
ioa
mg/i,
rather than the
50
mg/i
figure
suggested
by
the
Agency.
63-125
9
The
Agency,
in
its
first
notice comment,
filed
July
17,
1984,
agreed
that
IPC
is
entitled to site—specific relief,
They
disagreed,
however, as to the degree of relief that should be
granted.
The
Agency’s
position
is
that
the
proposed
100
mg/I
daily
maximum
is less stringent than
the
levels
of
treatment
that
are
demonstrably
achievable,
Three
years
of
data indicates
that
the
system
can
consistently achieve effluent under
50 mg/i,
Consequently,
this demonstrated ability should
be
the
basis
for
the
site—specific
rule
(Agency Comments on
First
Notice,
p.
3).
IPC,
in its
first
notice
comment
filed
July
23,
1984,
argUed
that
the
ash
pond
toretnent
system is a dynamic
process
that is
influenced
by many
foc’tors,
including factors
not
within
IPC’
s
control.
Thus, IPC
contended
the proposed daily maximum
of
100
mg/i
provides
a
reanrcnbly
achievable limitation
that
will
provide
relief
over
the life of the system and latitude during
periods
of
uncontrolittie fluctuation,
In its
first
notice
Opinion,
the Board
requested
the
participants
to address the possibility that
pontoons
with
silt
curtains,
or
rafts
or
utility
poles might improve
solids
settling.
IPC
responded
that these systems, collectively,
referred
to as
“floating baffles,” had proved ineffective,
It
is the
opinion of the Board that the 50
mg/i
daily
maximum
limitation
as the more appropriate standard
is better
supported
in
the
record,
Data submitted at hearing by IPC clear-
ly shows
the
system’s performance capability since construction
was completed
in May of 1982 (Petitioner’s Exhibit 9).
Effluent
has not
exceeded
50 mg/i for
three years.
In support of the 100
mg/i
standard,
IPC has argued that it
is more likely that the 50
mg/l standard
will
be
violated
than the 100 mg/i
standard
(R.
146).
While
this
is
most
certainly
a
true
statement,
it
is
also
likely
that the system will continue
to achieve TSS
concentrations
below 50 mg/i.
Site—specific relief here cannot
be based
on
abstract
and
unsupported
statements
regarding
“probabilities”
where
the
data
clearly supports
another
conclusion.
IPC
testified
that
it
is
probable that
as
the
ash
lagoon
system fills
over time,
TSS
concentrations
will
increase
CR,
136).
IPC,
however,
also
testified that these
future
concentrat-
ions
are
presently
unquantifiable.
Because of
this
uncertainty
and because of
the
ten
to twenty year life expectancy
of
the
lagoon system,
the
Board
is
unable to fashion a
TSS
limitation
that will
account
for
potential changes in the
lagoon
system’s
efficiency
in
the
distant
future.
At present,
there
is
no
support
in
the record for any
limitation
other
than
50
mg/i.
While
site—specific
rules
are
intended to provide long—term
relief,
there are limits
to
the Board’s ability
to
do
so
where
future
conditions
cannot
be predicted,
A more
important
factor,
when
creating
site—specific rules,
is
to base them on system
capabilities
and limitations
as reflected
by
the
available
data.
Today’s
rule
reflects
this principle,
63-128
10
ORDER
The
Board
hereby
adopts
the
following
rul~
o
be
codified
as
35
Iii, Adm.
Co&
304.209,
and
instructs
the
a
‘
of
the
Board
to
file
this
rule
with
the
Secretary
of
Sta
e
TITLE
35,
EIWIRONMENTAL
PROT~CTI N
SUBTIILE
C:
WATER
POLLUTION
CHAPTER
1:
POLLUTION
CONTROL
BOAFD
PART
304
SITE-SPECIFIC
RULES
AND
EXCEPTIONS
NOF
OF
GENERAL
APPLICABILITY
Section
304.209
Wood
River
Station
Total
S
ended
Solid
~ares
~
e
‘013
~s
conta
ined
inS e~on
~
~~all
n2~~l
the
dthch~
~theashondsstemo~noisPower~om~
4
~ver
~
I
t~e
~
~
~
ore
IT IS SO
ORDERED.
I,
Dorothy N.
Corn
Clerk
of
the
Illinor
a
io~ Control
Board,
hereby cci
i~.
a
ti.
above Opinioi
‘-dci was
adopted on the
~
I y of
,~___s;i~±~a&,.eL.
,
1985, by
a vote of
$—c’
/
Dorothy
N.
Gunn
C
k
Il)inois
Pollution
Con
rol
Board
