ILLINOIS POLLUTION CONTROL BOARD
May 9, 1986
IN THE MATTER OF:
)
)
JOINT PETITION OF THE CITY
)
OF CAIRO AND THE ILLINOIS
)
ENVIRONMENTAL PROTECTION
)
AGENCY FOR EXCEPTION TO THE
)
PCB 85-225
COMBINED SEWER OVERFLOW
)
REGULATIONS
)
)
MR. JOHN HOLLAND, SR. OF HOLLAND & HOLLAND APPEARED ON BEHALF OF
THE CITY OF CAIRO;
MR. STEPHEN C. EWART APPEARED ON BEHALF OF THE ILLINOIS
ENVIRONMENTAL PROTECTION AGENCY.
OPINION AND ORDER OF THE BOARD (by J. Marlin):
This matter comes before the Board upon the filing on
December 31, 1985 of a joint petition for a combined sewer
overflow (“CSO”) exception from 35 Ill. Adm. Code 306.305 (a) and
(b) by the City of Cairo (“City”) and the Illinois Environmental
Protection Agency (“Agency”). A public hearing was held in
Cairo, Illinois on March 20, 1986. No members of the public
attended and no public comments were received.
CS0 ~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
b) Additional flows, as determined by the Agency but not
less than ten times to sic average dry weather flow
for the design year, shall receive a minimum of primary
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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 Ill.
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 the City
had done. The joint petition seeks an exception based on minimal
discharge impact as provided in Section 306.361(a).
Was tewat~er System
The City is located at the confluence of the Ohio and
Mississippi Rivers
at
the southernmost tip of Illinois.
The Ohio
flows along the east side of the City while the Mississippi flows
along the west side. The City with its population of 6,000 is
surrounded by a levee system. The wastewater system is composed
of combined sewers, pump stations, and a primary wastewater
treatment plant (WWTP).
The City holds NPDES permit 1L0023825. The sewer system was
constructed prior to 1900 and consists of 33 miles of 8” to 72”
diameter combined sanitary and storm sewers, including the main
trunkline sewer and the interceptor sewers. Waste from the
sanitary sewer system in Future City, to the north of Cairo,
flows to a pump station and is pumped through a force main to a
manhole located at Sycamore and Union Streets, in Cairo (R. 13).
Another component of the wastewater system is the three
CSO’s with the three CSO pump stations located at 38th, 28th and
10th Streets. The 38th street pump station is used as a backup
only in emergencies and is considered abandoned by the U.S. Army
Corps of Engineers (Corps). The other pump stations, recently
constructed by the Corps, have five pumps each with a capacity of
60 cubic feet per second (cfs) at each station. These two pump
stations were designed to handle all possible stormwater
conditions (R. 14).
The two CSO’s currently used discharge approximately 200 to
220 days/year to the Ohio River when the river stage reaches 25
feet 295 mean sea level (MSL) or above. Their flow capacity is
approximately 38.75 MGD apiece and the maximum biochemical oxygen
demand (BOD) effluent concentration, using 1972 data, was 11.14
mg/i BOD (R. 25; Exh. B to Exh. 3).
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The mean annual flow of the Ohio River is 307.5 million
gallons/minute (MGM). During normal dry weather (below 25 foot
stage) the river’s flow ranges from 60 to 200 MGM. During
highwater (above 25 foot stage) the flow ranges from 200 to 735
MGM (Petition at 4).
There is another pump station at 10th Street which handles
dry weather flow. It Consists of two pumps with a capacity of
four million gallons per day. This station pumps directly to the
WWTP.
The WWTP, has a design average flow (DAF) of 1.3 million
gallons per day (MCD) and 1.9 MGD design maximum flow (R. 14).
The existing plant, built in 1963 (Petition at 6), includes a bar
screen, grit removal and a settling base. Solids are digested in
an aerobic digester and discarded in a sludge lagoon.
The influent BOD loading to the WWTP is between 60 to 100
mg/l or slightly less; usually about 60 to 70 mg/l BOD (R. 68-
9). The WWTP has a BOD removal rate of between 50 and 60 percent
and its effluent consistently meets the 30 mg/i BOD and 37 mg/l
total suspended solids effluent standards (R. 65-6, Agency Exh.
1).
When the Ohio River is below 25 on the gauge (295 MSL), the
outflow flood gates are open at each overflow. When a flash
flood rainfall of two to three inches per hour occurs during this
period, any flow over 1.9 MCD flows directly by gravity into the
Ohio River at 10th Street. Gauge readings below 25 (295 MSL)
occur on an average of 150 days per year and flash floods occur
approximately ten times during this period (R. 15-16).
When the Ohio River reaches a stage of 25, the outflow flood
gates are closed. When the river stage is between 25 and 34 (304
MSL), the WWTP treats 1.9 MCD. In addition, the 10th Street CSO
pump station is turned on approximately three times a day for
1/2
hour periods. The pump station at 28th Street is activated only
during flash floods (R. 16).
Between a river stage of 34 and 40, the WWTP treats 1.9 MCD,
the 10th Street CSO pump station operates approximately three
times per day for one hour periods, and the 28th Street pump
station is activated during flash floods (R. 16—17).
At a river stage above 40, the WWTP treates 1.9 MCD. The
10th Street CSO pump station operates three times per day for
one-and-a-half to two-and-a-half hour periods.
The 28th Street
pump station
is
activated during flash floods.
Gauge readings
above 25 occur approximately 200 days per year (R. 17).
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Existing• CSO I~pac~t
The City offers 1972 data from the Corps asserting that the
CSO discharges have negligible impact on the Ohio River. The
Corps data shows that once the CSO’s discharge to the river, the
maximum BOD residual concentration in the Ohio River from the CSO
discharge, assuming full mixing was 0.00188 mg/l at a river stage
of 30 (300 MSL). In most cases, this BOD residual ranged from
0.0035 to 0.000089 mg/l BOD ER. 25; Exh. C to Exh. 3 (Petition).
The City alludes to a 1977 variance petition in PCB 77-256
which allegedly contains Agency sampling data one mile up and
downstream of the WWTP showing no increase in BOD, suspended
solids and fecal coliform in the Ohio River due to the City’s
discharges. While the City introduced two Board Opinions and
Orders into evidence (Exh. 7), it failed to include a copy of the
1977 variance petition. Other data in the instant record shows
compliance with the effluent standards for the WWTP and a very
small BOD residual in the Ohio River due to the CSO discharges.
The bar screens at the pump stations remove any floatables (R.
45). Although fecal coliforrn counts are not given, the Board
would expect that the counts would be low for the CSO discharges
due to the amount of infiltration and inflow in the sewer
system. Any residual amounts in the Ohio river due to CSO
discharges would be negligible due to the relatively large flow
of the Ohio River.
CSO ResGiut ion
Pla~n
Two alternatives are available to the
City to achieve
compliance with the CSO regulations. The first, the construction
of a 7 MC stormwater retention lagoon, would cost $2.5 million.
This alternative was considered not feasible for many reasons:
sufficient land was unavailable; sandy soil and high groundwater
conditions necessitated a liner in the lagoon, increasing the
cost substantially; and because of the amount of flow involved in
high water CSO events, a 7 MG lagoon would be filled in a very
short time (R. 21-2).
The second alternative would be the separation of the
combined sewers at a total cost of $30 million. The City cannot
afford this alternative because the City would exceed its debt
limit (R. 47—8). 111. Rev. Stat. 1985, ch. 24, par. 8—5—1.
The City has chosen instead to upgrade its WWTP facilities,
which in turn would be able to treat more flow, thereby reducing
the extent of CSO discharges. A diagram of the upgrade is in the
petition (Exh. D to Exh. 3). The WWTP, once upgraded, will be an
advanced primary treatment facility based on physical/chemical
rather than biological treatment. The upgrade will add a primary
clarifier, a chemical mixing basin, one additional digester,
three new blowers, two chlorine contact tanks, two chlorinators,
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and a coil sludge filter. Associated process piping, pumping and
controls will be in accordance with Illinois- Recommended
Standards.for~.Sewerag-e~Wo-rks(Exh. 9~Exh. D to Exh. 3). The
upgraded WWTP DAF will be 1.3 MCD and the peak flow capacity will
be increased from 1.9 to 3.0 MCD (R. 29-30).
The capital cost of the WWTP upgrade is $1,700,000 (R. 26-
7). Operation and maintenance costs will increase from $150,000
to $190,000 per year (Petition at 5). The City is currently in
project priority range for a 55 percent USEPA construction grant
and a 15 percent state grant. If both grants are awarded, the
City’s share of the project would be $510,000; with only the
federal grant, $765,000; with only the state grant, Sl,445,000
CR. 26-7). The City does not anticipate exceeding its debt
limit.
City Programs
The City currently has active street sweeping and sewer
cleaning programs. Streets are cleaned about once a month (R.
42). Any blockages in smaller sewers are cleaned as well as pump
stations CR. 43). The City also has an ordinance which mandates
separated sewer connections in new buildings (R. 36)
,
as well as
outlawing connections of roof drains to the sewers (R. 37). The
City plans to continue these programs.
Conclus ion
Having considered the evidence and the factors enumerated in
Section 306.361(a), the Board finds that the Cairo CSO
discharges, after implementation of the WWTP upgrade, will have
minimal impact. The upgrade will increase the treatment capacity
of the WWTP, thereby reducing the extent of the CSO discharges.
The Board will grant an exception with language similar to
that recommended by the City and the Agency. The City will be
required to certify acceptance of the Order.
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.
Finally, in order not to give the City a total exemption
from treating dry weather flows under Section 306.305(a),
language has been added to limit dry weather flow relief to those
dry weather flows beyond the capabilities of its WWTP.
This Opinion constitutes the Boardts findings of fact and
conclusions of law in this matter.
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6
ORDER
The City of Cairo (City) is hereby granted an exception from
35 Ill.
Adrn.
Code 306.305(a) as such provision relates to first
flush
of storm flows and dry weather flows beyond the
capabilities of its wastewater treatment plant and Section
306.305(b) for combined sewer overflows to the Ohio River,
subject to the following conditions:
I. The City shall construct and operate the improvements to
its wastewater treatment plant as described in Croup
Exhibit 9 no later than November 1, 1987.
2. The City shall follow the operation and maintenance
procedures identified in Group Exhibit 9, specifically
street cleaning, pump station cleansing and outflow
structure cleansing, as well as those procedures in
paragraph (3) below.
3. The City, for a period of two years after the date for
completion of the wastewater treatment plant upgrade
identified in paragraph (1) above, shall submit an
annual report to the Agency at the address below on
inspections of the discharge areas for sludge deposits.
4. This grant of exception does not preclude the Agency
from exercising its authority to require as a permit
condition a CSO monitoring program sufficient to assess
compliance with this exception and any other Board
regulations, including Section 306.305(c), and other
controls if needed for compliance, including compliance
with water quality standards.
5. This grant of exception is not to be construed as
affecting the enforceability of any provisions of this
exception, other Board regulations, or the Environmental
Protection Act.
6. Within forty—five (45) days of the date of this Order,
the City shall execute a Certification of Acceptance and
Agreement to be bound by all terms and conditions of the
exception granted. This Certification shall be
submitted to the Agency at 2200 Churchill Road,
Springfield, Illinois 62706. The form of said
Certification shall be as follows:
Cer•ti-fi-ca-t ion
I, (We)
,
hereby
accept and agree to be bound by all terms and conditions of the
Order of the Pollution Control Board in PCB 85-225, dated
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7
Petitioner
Authorized Agent
Title
Date
IT IS SO ORDERED.
J.D. Dumelle and J. Anderson concurred.
I, Dorothy M. Cunn, Clerk of the Illinois Pollution Control
Board, hereby certify that the above 0 inion and Order was
adopted on the
9~/..
day of
~
,
1986,
by a vote
of
7—~
.
.
• ~..
Dorothy M. ~unn, Clerk
Illinois Pollution Control Board
69-440