ILLINOIS POLLUTION CONTROL BOARD
May
9, 1986
IN THE MATTER OF:
)
)
THE JOINT PETITION OF THE CITY
)
OF PEORIA AND THE ILLINOIS
)
PCB 85-210
ENVIRONMENTAL PROTECTION AGENCY
)
FOR EXCEPTION OF THE COMBINED
)
SEWER OVERFLOW REGULATIONS
)
MR. RALPH EVANS APPEARED ON BEHALF OF THE CITY OF PEORIA
MR.
E. WILLIAM HUTTON,
ESQ. APPEARED ON BEHALF OF THE
ENVIRONMENTAL PROTECTION AGENCY
OPINION AND ORDER OF THE BOARD
(by
J. Marlin):
This matter comes before the Board upon
a joint petition for
a combined sewer overflow
(CSO) exception filed pursuant to
35
Ill. Adm. Code 306.305 by the City of Peoria
(Peoria) and the
Illinois Environmental Protection Agency (Agency).
The Board
conducted
a public hearing
in Peoria on February
7,
1986.
Members
of the press and public attended the hearing.
The Board
has received no comment,
other than that offered by Peoria and
the Agency at the hearing.
As is discussed belo~w, on March 14,
1986 the board
requested additional information from Peoria and the Agency.
The
Board received the response to the Interim Order on May
2,
1986,
together with a motion for leave
to file instanter,
which is
granted.
CSO Regulations
The CSO regulations are contained in 35 Ill. Adm. Code
306.302
et seq.
They were amended
in R81-17,
51 PCB 383,
March
24,
1983.
Section 306.305 provides
as follows:
All combined sewer overflows and treatment plant
bypasses shall be given sufficient treatment to prevent
pollution,
or the violation of applicable water
standards unless an exception has been granted by the
Board pursuant to Subpart
D.
Sufficient treatment shall Consist of the following:
a)
All dry weather flows, and the first
flush of
storm flows as determined by the Agency,
shall
meet the applicable effluent standards;
and
69-407
2
b)
Additional flows,
as determined by the Agency
but not less than ten
times
to average dry
weather flow for the design year,
shall
receive
a
minimum
of
primary
treatment
and
disinfection
with
adequate
retention
time;
and
c)
Flows
in excess of those described in
subsection
(b)
shall be treated,
in whole or
in part,
to the extent necessary to prevent
accumulations of sludge deposits,
floating
debris and solids
in accordance with
35
Iii.
Adm.
Code 302.203, and to prevent depression
of oxygen levels; or
d)
Compliance
with
a
treatment program authorized
by
the
Board
in
an
exception
granted
pursuant
to
Subpart
D.
Subpart
D
allows
the
discharger
to file
a
petition
for
an
exception either singly, or jointly with the Agency, as Peoria
has done.
A joint petition may seek an exception based on
minimal discharge
impact
as provided
in Section 3O6.361(a):
An exception justification based
upon minimal discharge
impact shall include,
as
a minimum, an evaluation of
receiving stream ratios, known stream uses,
accessibility to stream and side land use activities
(residential, commercial, agricultural,
industrial,
recreational), frequency and extent of overflow events,
inspections
of unnatural bottom deposits, odors,
unnatural floating material or color,
stream morphology
and results of limited stream chemical analyses.
Where
a minimal impact exception cannot be established, or
where an exception will include modification of water quality
standards,
Section 306.361(b) allows an alternative
justification.
In addition to the elements of paragraph
(a), the
justification must include:
(E)valuations of stream sediment analyses, biological
surveys
(including habitat assessment), and thorough
stream chemical analyses that may include but are not
limited to analysis of parameters regulated in 35
Iii.
Adm. Code 302, analysis of toxics or metals
if the
collection system tributary to the overflow receives
wastes which might contain them,
sediment oxygen
demand,
volatile solids, and diurnal monitoring under
both dry and wet weather conditions.
Peoria and the Agency believe they have made the “minimal
impact” showing pursuant to Section 306.305(a).
Alternatively,
69-408
3
they believe the petition is justified pursuant to Section
306.305(b).
(R.41).
Exhibits
Peoria introduced four studies as exhibits at
the hearing
(also referred to
as attachments A through D to the petition):
Exhibit
1
Facilities Plan
Exhibit
2
An Assessment of the Impact of Combined Sewer
Overflows at Peoria on the Waters of the
Illinois Waterway,
Dept. of Energy and Natural
Resources,
September,
1983.
Exhibit
3
The Procedures, Observations,
and Results of
a
Mixing Zone Study
for Combined Sewer Overflows
at Peoria,
Illinois, Department
of Energy and
Natural Resources, October
1984.
Exhibit
4
Report
on Combined Sewer Overflow Control
Plan, Greeley and Hanson and Randolph and
Associates,
Inc., December,
1985.
Illinois River
Peoria is situated on the west bank of the Illinois River.
East Peoria is directly across
the river.
The Illinois River at
Peoria forms
a pool known as Peoria
Lake.
It
is used for water skiing and other recreational
purposes.
Immediately below Peoria, the river is less suited
for
recreation because
it
is narrow, with heavy barge traffic and
barge moorings.
Access to the River from the city is by way of
marinas, all of which will
be upstream of the CSO outfalls upon
completion of the project described below
(R.
44).
The River has an average flow of about 15,000 cubic feet per
second
(CFS), with a ten-year low flow of around 4000 CFS
(R.
28).
Peoria conducted
a study to determine the CSO impact on
water
quality,
sediment and benthic organisms.
Parameters were
measured above, among and below the CSO discharges during the
summer of
1982.
River flow was around 6000 to
101000 CFS.
Measurements were taken after CSO overflows
in response to
rainfall events of 0.33 to 1.44 inches per hour (R. 23).
Most water quality parameters measured were usually well
within the general use water quality standards of
35 Ill. Adm.
Code 302,
including dissolved oxygen, pH, ammonia, cadmium,
lead,
zinc and temperature.
(R.24).
Four of 654 samples violated the
69-409
4
lead standard.
The water quality standard for copper was
violated above and below the CSO discharges.
The CSO
contribution to the violation was determined to be imperceptible
(R. 25).
Other parameters measured,
for which there are no water
quality standards, included biochemical oxygen demand
(BOD),
suspended solids and turbidity.
The CSO contributions to
suspended solids and turbidity were not significant compared with
that originating from small water courses and overland drainage
(R.
25).
Overland urban drainage and other discharges were
thought by petitioner to be as significant as CSO’s with respect
to BOD water quality
(R. 26).
The study determined that the CSO outfalls were contributing
to violations of the water quality standard
for fecal coliform
and were introducing undesirable floatables into the River
(R.
26).
The fecal coliform standard
is 200 Counts per 100 ml
(Section 302.209).
Floating debris
is prohibited by Section
302.203.
Above the CSO discharges
fecal. coliform ranged from
4
to 50 counts per 100 ml during dry weather, and from
3 to 4900
after rainfall events.
Near and below the CSO discharges fecal
coliform ranged from
5 to 340 counts per 100 ml during dry
weather, but ranged up to 240,000 counts per 100 ml after
rainfall events.
(R.
26,
Exh.
2,
p.
37).
Peoria also conducted a study of the bottom sediments,
including composition, percent volatile solids and concentrations
of cadmium, copper,
lead, zinc,
grease and oil.
(R.
24).
Bottom
sediments
in the vicinity of CSO~discharges were primarily sand,
or a mixture of sand and rock.
No sludge accumulations were
encountered.
Sediments showed an increase in grease and oil,
zinc,
and lead,
which are indicative of urban storm drainage,
rather than sewage
(R.
26,
Exh.
2,
p.
59).
Bottom dwelling organisms were typical of those residing
upstream in the Peoria pool.
Densities were not typical of
significant organic enrichment,
as would be the case if
sewage
were
a factor.
The limiting factor for
a well diversified bottom
dwelling population
is the unstable habitat of shifting sand,
compounded by excessive wave action, rather than water quality.
(R.
26,
Exh.
2,
p.
62).
Sewerage
The sewage system includes the original area of downtown
Peoria in which sewers were built before 1900.
They were
designed as storm sewers which ran under streets toward the
River.
With the development of indoor plumbing,
residential and
other sanitary sewers were connected to the storm
sewers.
In
1931, Peoria completed construction of the Riverfront Interceptor
sewer, which collected the dry weather flow from these sewers for
transportation to the sewage treatment plant1
Flows
in excess of
69-410
5
dry weather flow were bypassed to the River,
as well as flows
when the River was above the Interceptor.
In its present configuration, the Riverfront Interceptor
is
5.6 miles
long,
serving 5,080 acres,
about 2,950 acres of
combined sewers and 2,130 acres of separate sewers
(R. 29).
There are 23 regulator structures which discharge to 20 CSO
outfalls.
(R.
30).
The Interceptor has around
499 overflow
events per year
(R.
31).
The Riverfront Interceptor flows to the Greater Peoria
Sanitary District treatment plant.
It has
a capacity of about
80
million gallons per day (MGD) at the plant.
The plant also
receives up to 74 MGD from the Kickapoo Interceptor, which serves
only separate sewer areas
(R.
30,
47).
The plant treats up to
60 MGD.
It has an 8.5 million gallon
basin
to store first flush
flows for later treatment.
Flows
in
excess of
60 MCD receive primary sedimentation
(R.
30).
CSO Reduction Plan
Peoria presented
a plan for reducing the frequency and
intensity of CSO overflows.
This is detailed
in Exh.
4.
The
plan includes the elements described
in the following paragraphs.
Peoria will construct
a 5,100 foot,
48 inch sewer near the
northern end of the Interceptor.
This would provide storage for
about
21 percent
of the first
flush at the upper overflows, which
have the greatest impact on recreational uses
(R.
32).
Peoria will build diversion sewers to consolidate five CSO
outfalls into two outfalls, moving the outfalls downstream to
minimize recreational
impact
(R.
33).
A floatables capture
system will be provided
at many outfalls to capture floating
solids.
(Exh.
4,
p.
62,
R.
34).
No capture will be provided at
four downstream outfalls, because of excessive costs.
However,
the frequency and severity of overflows will be reduced by the
other aspects of the project
(Response to Interim Order).
Peoria will move regulator devices to higher ground,
so that
all will be functional up to the 25 year flood level.
This will
decrease the frequency of CSO discharges,
and allow treatment of
part of the flow up to the
25 year flood level.
(R.
34,
38).
Peoria will reduce the area served by combined sewers by
separating eight sewers.
Peoria will extend sanitary sewers to
divert sanitary flow from some of these,
and will extend storm
sewers to divert inflow from others
(R.
33,
34).
The treatment plant
capacity will
be increased to
accommodate higher flow rates from the interceptor.
Additional
69-411
6
pumps will be installed to increase discharge capacity at high
river
stages.
An additional sluice gate will be installed to
bypass
flows
in excess of 154 MCD
at the plant
(R.
35).
The overall project will cost $7,340,000, with an estimated
annual operating and maintenance cost of $102,000 per year.
A
1976 plan to eliminate all CSO discharges was estimated to cost
$38,000,000, with $467,000 in annual maintenance
(R.
36).
The
addition of downstream floatables capture would add more than
$2,900,000.
Adding swirl concentrator type floatable capture
systems at
six locations would add $6.1 million
(Response to
Interim Order).
Grant funding may be available for a part of the cost.
However,
local government
is prepared to pay the entire cost
if
necessary.
(R.
12,
15,
19).
Not included
in Exhibit
4,
and perhaps more important
in the
long run,
are Peoria’s efforts to reduce and eliminate combined
sewers
in conjunction with new development and redevelopment.
Peoria has an ordinance which prohibits the discharge of storm
flow into
a sanitary line
(R.
56).
New buildings must have
separate storm and sanitary sewer systems,
even if these
ultimately discharge to the same combined sewer.
(R. 56).
When
streets are reconstructed sewers are separated.
Also,
separate
sewers are constructed within area redevelopment projects
(R. 57).
New separated storm sewers have also been constructed
(R.
58).
Expected System Performance
Section 306.302 defines “sufficient treatment”
for CSO
discharges
in the absence of an exception.
This includes:
1.
Treatment of all dry weather flows.
2.
Treatment of first
flush flows.
3.
Primary treatment and disinfection for flows up to ten
times dry weather flow.
4.
Treatment of excess flows to prevent accumulations of
sludge deposits, floating debris,
solids, and to prevent
suppression of oxygen levels.
As noted above,
the existing system appears to be capable of
performing without accumulation of sludge deposits
or suppression
of oxygen levels.
Relocation of regulation devices will ensure
treatment of dry weather flow up to a 25-year flood.
First
flush can be defined in terms
of the flow required to
restore oxygen demand or suspended solids to normal values.
If
first flush is defined in terms of oxygen demand, Peoria will be
69-412
7
able
to capture and treat nearly all of the first
flush.
However,
it will fail to capture the entire first flush of
suspended solids.
Because of the low oxygen demand of the
suspended solids flush,
Peoria believes
it represents
a wash-out
of grit collected by the storm sewer system,
rather than of
sanitary sewage solids.
Such solids would also be washed out of
a separated storm sewer system.
(R.
53; Exh.
4, p.
30).
The Interceptor will capture from 3.8 to 22 times the dry
weather flow at various CSO outfalls.
(R.
33,
35).
Overall,
the
project will result
in treatment of four times dry weather flow.
(R.
55).
The downstream CSO discharges will be without provision for
capture of floating solids.
(R.
35).
However,
these will
discharge less frequently and are located below the area of heavy
recreational use.
Peoria will remain subject to Sections 302.203
and
306.305(c), which prohibit these discharges
(Response to
Interim Order).
Overall the number of CSO discharge events is expected to
drop from 499 to 161 per year
(R. 36).
The number of days during
which
an overflow occurs would be reduced from around
40 to
around
28
(Exh.
4,
p. 84-85).
Improvement
in Water Quality
Section 302.102 requires co~mpliancewith water quality
standards at the edge of
a mixing zone.
Because of the size of
the Illinois River,
Peoria is able to take advantage of
a large
amount of dilution in
a reasonable mixing zone even under low
flow conditions.
Peoria has conducted
a study to define the size
of an allowable mixing zone.
(Exh.
3).
The plan is expected to
result
in
a considerable reduction in fecal coliform levels
outside the mixing zone.
Nevertheless,
there will continue to be
some violation of this standard.
(R.
45).
Peoria has requested
no modification to the water quality standard.
Conclusion
Having considered the evidence and the factors enumerated
in
Section 306.361(a),
the Board concludes that the Peoria CSO
discharges will have
a minimal impact.
Although there will
continue to be some violations of the water quality standard for
fecal coliform,
they will be greatly reduced
in severity and
frequency, and generally moved downstream away from areas of
heavy recreational use.
The Board will grant an exception with
language similar to that recommended by Peoria and the Agency.
In order to assure that this Order
is not construed as
authorizing Peoria to abandon its other efforts to reduce
its CSO
discharges,
the Board will add conditions obligating Peoria to
continue with its program of separating sewers
in conjunction
69-413
8
with development projects.
The Board recognizes
that
in certain
situations this may not be feasible from an engineering
standpoint.
The Board
notes that the relief
is restricted only to those
substantive requirements for effluent treatment of CSO’s, and not
to relief from water quality standards.
To insure that this
issue is clear, the Board will introduce into the Order language
identifying the scope
of the exception as granted.
This Opinion constitutes the Board’s
finding of fact and
conclusions of law
in this matter.
ORDER
1)
The City of Peoria
is granted an exception from
35
Ill.
Adm.
Code 306.305(a) and
(b), subject to the following conditions:
a)
All components of the recommended combined sewer
overflow plan presented in Exhibit
4, and generally
described
in the above Opinion,
shall be implemented in
accordance with the time schedule contained in Paragraph
2.
b)
Within eighteen
(18) months after completion of system
improvements,
the City of Peoria shall report
to the
Illinois Environmental Protection Agency on performance
and effectiveness of th~eimprovements, including extent
of overflow reduction, attainment of additional excess
flow treatment at Greater Peoria Sanitary District
Treatment Facility, adequacy of floatable capture
appurtenances at each remaining overflow point and
performance of backflow prevention facilities.
c)
The City of Peoria shall,
in addition to the plan
contained
in Exhibit
4:
1)
Prohibit new connections of residential downspouts
to sanitary sewers;
ii)
Require that sanitary sewers and storm sewers exit
new buildings as two separate lines;
iii) Construct separate storm and sanitary sewers to the
extent feasible when streets are reconstructed and
when area redevelopment occurs.
2)
The City of Peoria shall fully implement all requirements of
Paragraph
1 in accordance with the following time schedule:
69-414
9
I~pl~eme
n~ta•t
ion. Schedul~e
Ev~e
n~t
Begin
Design of Improvements
Complete Design of
Improvements
Complete Securing of Land and Easements
Secure Construction Financing
Construction of
Improvements
Phase
I
-Treatment Plant and
)
Upstream Storage Sewer
)
-Sewer Separations
)
Phase III -Remainder of Recommended)
Project
)
Achieve Full Operational
Status
Phase
II
Data
October 1986
February 1988
March 1988
April 1988
June 1988 thru
June 1990
June 1989 thru
September 1992
June 1990 thru
August 1992
December 1992
3)
Within forty-five
(45) days ,after the date of this Order,
the
City of Peoria shall execute
a Certification of Acceptance
and Agreement to be bound to all terms and conditions of this
exception.
Said Certification shall be submitted to the
Illinois Environmental Protection Agency at 2200 Churchill
Road;
Springfield, Illinois 62706.
The form of said
Certification shall be
as
follows:
Cer~tificat.i~on
I,
(We)
hereby accept
and agree to be bound by all terms and conditions of the Order of
the Pollution Control Board in PCB 85-210, _______________________
1986.
Pet it ion er
Authorized Agent
Title
69-415
10
Date
IT IS SO ORDERED.
J.D. Dumelle and 3. Anderson concurred.
J.T. Meyer and B. Forcade dissented.
I,
Dorothy
M. Gunn, Clerk of the Illinois Pollution Control
Board, hereby certify that the above Opinion and Order was
adopted on the
9t~..
day of
~
,
1986, by a vote
of
..
Dorothy
~.
C nn,
Clerk
Illinois Pollution Control Board
69-416
