ILLINOIS POLLUTION CONTROL BOARD
January
8,
1981
CITY OF CAIRO,
Petitioner,
v.
)
PCB 80—161
ILLINOIS ENVIRONMENTAL PROTECTION
AGENCY,
)
Respondent.
OPINION AND ORDER OF THE BOARD
(by J.D.
Dumelle):
The
City of Cairo
(Cairo)
filed a Petition for Variance
Extension on September
5,
1980,
requesting an extension of
the
variance granted by the Board in PCB 77—256
(March
16,
1978,
29
PCB 371). An amended petition was filed on October 17,
1980,
requesting a variance from Rule 602(c)
of Chapter
3:
Water
Pollution Regulations, for 5 years or until proceedings in
R77—12 are complete, whichever occurs first.
On December
1,
1980,
the Illinois Environmental Protection Agency
(Agency)
reco~ei~ded
that the vaitance be qranted sub5ect to certain
conditions.
Hearing was waived,
and none was held.
The conditions evident in Cairo at the time of the variance
petition in PCB 77—256 are essentially unaltered,
Cairo is
located at the confluence of the Mississippi and Ohio Rivers
at
the southern tip of Illinois,
Cairo’s current sewage system
serves approximately 6,500 people.
The facility consists of two
aerated grit tanks, two parallel preaeration tanks,
a primary
settling tank and two aerobic digesters.
The design average flow
is 1.9 million gallons per day
(MGD) and provides treatment for
a
maximun flow of 3.7 MGD,
The hydraulic load to the Cairo facility typically exceeds
1.0
MGD
or 10,000 population equivalents
(PE),
However,
the
organic load is substantially less than the 10,000 PE due to
the
massive infiltration into the City~scombined sewer
system.
Discharge from the Cairo facility flows
into the Ohio River which
has a minimum estimated flow at Cairo of 29,200 MGD,
This
provides dilution at a ratio of 20,000:
1.
Also serving the City of Cairo
is a combined sewer system
and four lift stations.
One station pumps dry weather flow
to the Cairo STP; the other three 1i!t stations pick up excess
flow.
When incoming flow exceeds the maximum capacity of this
lift station, the excess flow is pumped by the other three
40—261
—2—
lift stations directly to the Ohio River,
These
lift stations
are the
subject of this variance extension.
Rule 602(c) provides in pertinent part that:
All combined sewer overflows and treatment plant
bypasses shall be given sufficient treatment to prevent
water pollution or the violation of applicable water
quality standards. Sufficient treatment shall consist
of the following:
(1)
All dry weather flows,
and the first
flush of
storm flows as determined by the Agency,
shall
meet the applicable effluent standards;
(2)
Additional flows,
as determined by the Agency hut
not less than ten times
the average dry weather
flow for the design year,
shall receive a
minimum
of primary treatment
and
disinfection with
adequate detention time;
The combined sewer system in Cairo, Illinois suffers from
some quite unusual infiltration problems which
are
directly
related to the level of the rivers.
Because the
City
is
located
on a sand spit between the Ohio and Mississippi Rivers,
local
groundwater levels tend to correspond closely to the water stages
of those rivers.
At 28 feet or higher,
infiltration becomes
a
serious problem and at 30 feet bypassing at
the
lift stations
occurs.
During
this
time,
the
Cairo STP receives the amount of
wastewater it is capable of treating.
However, when the Ohio
River reaches
a river stage of 50,0-50,5 feet, bypassing occurs
at the plant.
At 51,0—51.5
feet,
the Ohio River covers the
Cairo
STP’s discharge pipe and flood gates are closed shutting down
the
Cairo STP.
Thus, any environmental impact
is self~limiting
since untreated water
is discharged only
at times when there
is maximum dilution due to flooding.
The City of Cairo
is currently
in
a Step
1 phase of the
federal construction grants program.
Although petitioner
has
submitted a precise plan of method of control which will
ultimately bring the Cairo sewage system
into
compliance for
flows up to and including
1.9 MGD, petitioner
is
unable to
present plans by which
it will eventually comply
with Rule 602(c)
of Chapter
3 for the three pump stations.
In this petition,
Cairo has requested an extension of the variance, but there is no
indication as to how compliance with the technical requirements
of Rule 602(c) will be achieved by the end of that period.
However, the three pump stations
in the Cairo sewerage system
provide necessary protection against flooding so that the City
may be maintained for human habitation. Furthermore, when the
pump stations become operational,
the discharge of excess flow
does not violate Illinois effluent
limitations for BOD5 or for
suspended solids
(see 29 PCB 372—3)and therefore does not pose
a
threat of pollution.
The fecal coliform limitations
is, however,
exceeded, both for first
flush and for additional
flows.
40—262
Petitioner alleges that to treat its flows
in the sewer
system which at times equal
56
MGD
would cause
a
severe financial
hardship for any small city required to disinfect wastewater.
Furthermore,
it
is highly unlikely that a conventional separate
sanitary sewer system,
free from excess infiltration could be
constructed to serve the City of Cairo at a reasonable cost.
As
noted
in the Board’s Opinion in PCB 77—256, the cost for
separating the combined sewer system would be $25,000,000
(29 PCB
372).
Therefore, the Board finds that re9uiring petitioner
to
comply with the fecal coliform
(disinfection) requirements of
Rule 602(c) would impose an arbitary or unreasonable hardship.
Apparently,
the first
flush violations will be remedied once
the federal grant construction work is completed.
When POB
77—256 was decided on March
16,
1978, Cairo was
in Step
1 of that
process and remains
so.
The record offers no insight to the
Board as
to why
no progress has been made since 1978,
but neither
are dilatory actions alleged.
Because the delay
is not explained
the five year variance will not be granted but the Board will
grant a variance until January
31,
1983,
Any future proceedings
should clearly discuss reasons
for delay,
This Opinion constitutes the Boards findings of fact and
conclusions of law
in this matter.
ORDER
The City of Cairo
is granted a variance until January
31,
1983,
from Rules 602(c)(1) and
(2)
of Chapter
3:
Water Pollution
Regulations,
in order
to allow
it
to discharge first
flush and
additional flows
from its sewage system which exceed 1.9 MGD into
the Ohio River without treatment,
subject to the following
conditions:
1.
Petitioner shall provide treatment for all flows u~to
and including 1.9 MCD; and
2.
Petitioner shall submit to the Agency
a Certification
of Acceptance within 45 days of the date of this Order.
This Certification shall be addressed to the Illinois
Environmental Protection Agency Variance Unit,
Division of Water Pollution Control,
2200 Churchill
Road Springfield, Illinois
62706.
The form of such
certification shall be as follows:
40—263
—4—
CERTI~ICATEOt~
The
City
of
Cairo
has
received
arid
undt~r~andsthe
Ocder
t:he Illinois Pollution Control Boarr~ in PCB S0—161 and ~r~1y
~c~epts
said
Order
and
agrees
to
be
houn~1by
~ll of the
conditions
thereof.
signed
Title
Date
IT
IS
SO
ORDERED,
I,
Christan
L.
Moffett,
Clerk
of
the Illinois Pollution
Control Board, hereby certify that the above Opinion and Order
was
adopted on the
:
~“
day
of
~
1980 by
a
vote of
~
~
Chi~istanL. Moffett,
Clerk
Illinois Pollution Control
Boar’!
40—264