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