ILLINOIS POLLUTION CONTROL BOARD

February

26, 1986

IN THE MATTER OF:

)

JOINT PETITION OF TUE CITY OF

)

PCB 85—211

MARSEILLES AND THE ILLINOIS

ENVIRONMENTAL PROTECTION

)

AGENCY FOR EXCEPTION TO TUE

COMBINED

SEWER

OVERFLOW

REGULATIONS

ML. KEITH

R.

LEIGH APPEARED ON BEHALF OF TUE CITY OF MARSEILLES,.

MR1 THOMAS DAVIS APPEARED ON

BEHALF OF

THE

ILLINOIS

ENVIRONMENTAL

PROTECTION AGENCYI

OPINION AND ORDER OF THE BOARD

(by R~C~ Flemal):

This matter comes before the Board

upon a December

26,

1985,

joint petition filed

on behalf of the City of Marseilles

(“City”)

and

the Illinois Environmental Protection Agency

(“Agency”)

for

an exception to

35

1111

~dm1 Code 3061305(b)

of the Board’s

combined sewer overflow

(CSO)

regulations

as they apply to the

City’s existing C3O and sewage treatment facilities.~

Section

3061305(b) provides

as follows:

Additional

flows,

as determined

by the Agency but 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 retention time1

The “additional flows”

identified

in this Section

refer

to

discharges

above

and beyond all dry weather

flows

and the first

flush of storm flows,

as specified

in Section

3061305(a),.

Hearing was held

on January 30,

1986,

at the Marseilles

City

HalL

Testimony and exhibits were presented only by Petitioners;

no members of the public were

in attendance.~ There was

no

disagreement

as to the facts1

Petitioners contend that existing overflows from the City’s

combined storm and sanitary sewer system have minimal

impact on

the water

quality of, and do not restrict the use of,

the

Illinois River

(the receiving stream)1

Petitioners also propose

that Marseilles undertake

a program which would enable the City

to capture

and treat first flush flows and

to otherwise improve

the capabilities

of

its sewage treatment system,

and

thus further

minimize any impact of its CSO discharges1

---

—2—

In Board review of

a joint petition, granting

an exception

to C3O rules

based upon minimal

discharge impact,

as

is the case

here,

is conditioned upon Petitioners providing justification

according to the provisions

of

35

111,.

kdm,.

Code

306,.36l(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 analyses1

The BoaLd

finds that Petitioners have provided the

information specified in Section

306,.361(a),

and that such

information

indicates that the granting

of the requested

exception would have

a minimal discharge

impact1

Petitioners

also contend

that the alternative

to granting

of the requested

exception would entail

a costly, large—scale expansion of the

sewage treatment plant1

In view of these considerations the

Board will grant the requested exception,

subject to conditions

as proposed by Petitioners,.

DISCHARGE IMPACT

The City

is located on the north bank

of the Illinois River

at approximately river mile

246 and approximately

25 miles below

the confluence of

the Des Plaines and Kankakee Rivers

(head of

the

Illinois River),.

The City

is served

by approximately 12,000

L1F,.

of combined sewers

and approximately 57,000

L1F1

of separate

sanitary

sewers,.

The collection system drains through

a single

27

inch sewer which has an estimated maximum capacity of

817

million gallons per day

(MGD),.

This

27

inch sewer discharges

to

the Marseilles wastewater treatment plant1

Overflows occur when

flows

in the

27 inch sanitary sewer exceed

the pumping capacity

of

the primary treatment plant or primary flows exceed

the

capacity of the primary clarifier;

this occurs at

a flow rate

between 2q30 and

2,.48

MGD, depending upon the head

in the system

(R1

at

87),.

Both sources

of overflow are discharged

to the

Illinois River through

a single

30

inch line which

also carries

the treated discharge from the plant1

No other

overflows exist

in the Marseilles collection system1

At ~4arseillesthe Illinois River

consists of

two channels,

a

north natural channel approximately 300 feet wide,

and

a narrow

south channel modified

for

navigation1

The two channels are

separated by

a forested

island1

The discharge point of the 30

inch bypass line

is

located on the north side of the north

channel1

The river bottom in the north channel

is rocky

(Ex

2)

and has

a normal

4 to

6 foot depth1

This part of

the river

has

no channelization or dredging for approximately one mile

in each

of the upstream and downstream directions~

At the point

of

---

—3—

discharge and

for approximately one mile downstream the north

bank

of the north channel

is bordered by

a ten—foot wide forested

belt,

behind which

is agricultural land1

Petitioners contend

that the near—stream land

is not utilized nor

accessible

by

children for recreational activities,

nor

is the river

suitable

for recreational activities other

than fishing

for

at least

one

mile downstream due to rapid current and

the shallow,

rocky river

bottom

(Ex

7,

p.

8);

sport fishing

is

a popular activity

(R,.

at

45).

Petitioners contend that

the impact of the C30 overflow on

the Illinois River

is negligible,

noting that the

7 day

10 year

low flow of the Illinois River

in the vicinity of Marseilles

is

2086 MGD

or 3228 cubic feet per

second*,.

The maximum peak hourly

flow rate

to the treatment plant

is approximately 9.43

MGD,.

(Ex

4,

~,.

18;

R1

at

89),.

Assuming all

of the

sewage from the

combined

system in excess of plant capacity were dumped

into

the

river, which

it

is

not,

the total discharge into the rivet would

be

7,.46

MGD,.

This provides

a dilution ratio

of

230

to

1 at

low

flow1

At average flow rates, the dilution ratio would be

considerably higher,

making

the

impact

on the Illinois River

considerably

less,.

Petitioners

also note (Petition,

p,.

3):

The first

flush analysis established

a volume of

405,000

gallons.

Even

if the entire

first flush

is bypassed

to the

Illinois River, which

it

is

not,

it

is approximately

0,.0l9

of the low flow for the Illinois River1

The first flush volume of 405,000 gallons cited

above was

calculated from analysis of

an overflow event which occurred on

June l~,1993

(Ex

1, p~ 17),.

At hearing the City noted that an

earlier event, which occurred on May 1,

1983, but which had not

been previously analyzed

in this context,

produced an estimated

first flush of 651,300

gallons

(Ex

1, p~ 18),

more than 50

larger

than that cited

in the Petition.

As regards impact

on the

receiving stream,

the Board

notes that

this larger

first flush,

if entirely bypassed,

would

still constitute significantly less

than one percent of the low flow for

the Illinois

River,.

Petitioners estimate that

4

to

8 events sufficient

to cause

overflow occur

per year, depending upon rainfall conditions

(Ex

1,

p,. 9)~ Actual numbers

of events

in the past ten years have

varied from 17

in

1977

to none in 1981

(Ex 8,

p.

1).

Petitioners

further contend that the expected number

of events has decreased

over the past several years due to effective removal

of inflow

and infiltration sources

(R,.

at 38—40),

which

is supported by the

*Flow figures for

the Illinois River are

for

the combined

discharge of the north

and south channels,.

However,

according

to

PetitioneLs

(R.

at

57, 94),

flow

is predominantly through

the

north channel;

south channel

flow is

limited essentially

to

lockage,.

---

—4—

observation that within the past five years

the number

of

overflow events has averaged five per year verus 8~6per year

in

the preceeding five—year period

(Ex

1,

~1

9;

Ex

8,

~1

1),.

However,

the City believes that inflow and infiltration removals

have been

or are

in the process

of being taken

to their practical

limits,

and that therefore

no further

significant gains

in this

direction can be expected

(R1

at

30—31),.

Actual inspection

of the

river bank and

river bottom of the

north channel

indicate that there

is no visual effect of the

discharge on

the river

bank

or

river bottom

(Ex

2;

R,.

at

43),.

Included

in this inspection was determination via dye discharge

(Ex

2;

Ex

5,

p.

4)

of the mixing

zone, which was determined

to be

between

6

to

15 feet wide and

15

to

75 feet long

(Ex

5,

~1

4;

R,.

at

44), depending on flow conditions

in the river1

Petitioners

assert that sampling

of stream bottom sediments within the mixing

zone revealed no discoloration, abnormal textures,

or

odors

(Ex

7, P~3)~

Analyses

of instream water quality were undertaken,

representing both dry and wet weather sampling

(Ex 7,

p.

9),.

Sampling included

fecal coliform bacteria, dissolved oxygen,

five—day biochemical oxygen demand,

suspended solids, volatile

suspended solids, and

ammonia,.

Petitioners

note that during each

sampling from

an overflow event

the receiving water

of the

Illinois River was more turbid than water

coming from the outfall

(Ex

71,

p1

9).,.

Petitioners believe

that these data show that the

present bypassing has no effect on instream parameters,

other

than perhaps for fecal

coliform bacteria,.

With capture and

treatment of the

full first flush Petitioners assert that the

water quality impact will

be further minimized.

PROPOSED CONDITIONS

If

the exception

is granted,

the City proposes

to change

its

influent pumping capacity to be compatible with

a design maximum

flow

(DMF)

of

2,.0l6 MGD

(Ex

1,

~1

3)

and

to ensure that overflows

occur only while the treatment plant

is receiving

its DMFI

The

City further

proposes,

if the exception

is granted and

as

conditions

to such action,

to undertake

a facilities construction

program which,

at

an estimated cost of $474,650, would provide,

inter alia

(R,.

at 92),

for the following:

1)

Capture, storage

in

a

0,.65 million gallon storage tank

or basin, and complete

treatment

of the entire

first

flush,.

2)

Screening of all flows

received at

the plant prior

to

discharge1

3)

Increase

in flood protection by raising the existing

dikes around

the treatment plant

to

an elevation of

481,.l

feet, which

is 1.5 feet above the highest

recorded flood.

4)

Elimination of

river backup

into the

system..

---

—5—

The City intends to capture the first 650,000 gallons of

overflow

in its first flush storage system.

This capacity

Petitioners believe

is adequate

to insure treatment of the full

first flush

as well

as to provide

an adequate safety margin

(R.

at

53).

Storage

of some volume less than the actual

first flush

volume can be accommodated because that portion of the

first

flush which arrives

at the plant between

the time the dry weather

flow

is

initially exceeded and the time the OMF

is reached would

enter

the plant

and be treated immediately;

only the residual,

not—immediately—treated

first flush requires

storage.,

This

is

illustrated by the May 1,

1983 event.

Had the proposed plant

then been

in existence,

323,800 gallons

of the 651,300 gallon

first flush would have undergone immediate treatment and 327,500

gallons would have required storage and later

treatment

(Ex

1, p~

18).,

Thus,

a 650,000 gallon storage facility would have provided

a safety factor

of approximately

2.,

The City agrees

to undertake the three additional

facilities

construction items

(screening,

dike modification, and backup

elimination) as

a good faith effort

to assure

that the plant

operates

in such

a manner

as

to continue to minimize

environmental impact.

In view of

the evidence above,

the Board finds that granting

of

a

CSO

exception to the City of Marseilles,

based

on minimal

discharge impact,

is

justified.

The Board

therefore grants

the

exception, with conditions

as specified by ~JointPetitioners.,

This Opinion constitutes

the Board’s findings of fact and

conclusions

of law

in this matter.

ORDER

The City of Marseilles (City)

is hereby granted

an exceotion

from 35 Ill.

1~drn.,

Code 306.305(b),

for combined sewer overflows

into the Illinois River,

subject to the following conditions:

a)

The City shall ensure that overflows occur only while

the treatment plant

is receiving and treating

its

design maximum flow.

b)

The City shall provide

for capture

and complete

treatment of

the entire first flush.

c)

The

City shall provide

for screening of

all flows

received at the plant prior

to discharge.

d)

The City shall provide increased flood protection

for

the treatment plant by raising the existing dikes

around

the plant

to

an elevation

of

481.2

feet.

e)

The City shall eliminate river

backup into the system.

---

—6—

Within forty—five days of the date of this Order,

the City

shall

execute

a Certification

of Acceptance and Agreement to be

bound

to all

terms

and conditions

of this exception1

Said

Certification shall

be submitted to the Board,

as well

as

to the

Agency

at

2200 Churchill Road,

Springfield, Illinois 62706~

The

forty—five day period

shall

be held

in abeyance during any period

that this matter

is being

appealed,.

The form of said

Certification shall

be as follows:

CERTIFICATION

I,

(We), ____________________________, having read the

Order

of the Illinois Pollution Control Board,

in PCB 85—211,

dated February

26,

1986, understand

and accept

the said Order,

realizing

that such acceptance renders

all terms

and conditions

thereto binding and enforceable.

Petitioner

By:

Authorized Agent

Title

Date

IT

IS

SO

ORDERED,.

J,.

D,. Dumelle and Joan Anderson

concurred,.

I,

Dorothy

M,. Gunn,

Clerk of the Illinois Pollution Control

Board,

hereby certify that the above Opinion

an

Order was

adopted

on the ______________________ day of

~

,

1986,

byavoteof

7C

,.

~.

2/~

Dorothy

M1 Q~n, Clerk

Illinois Pollution Control Board