ILLINOIS POLLUTION CONTROL BOARD

May 9,

1986

IN THE MATTER

OF:

)

)

JOINT PETITION OF THE CITY

)

PCB 85-212

OF MORTON AND THE ILLINOIS

)

ENVIRONMENTAL PROTECTION

)

AGENCY FOR EXCEPTION TO THE

)

COMBINED SEWER OVERFLOW

)

REGULATIONS

)

MR. THOMAS

E.

DAVIES APPEARED ON BEHALF OF THE CITY OF MORTON;

MR.

E. WILLIAM HUTTON APPEARED ON BEHALF OF THE ILLINOIS

ENVIRONMENTAL PROTECTION AGENCY.

OPINION AND ORDER OF THE BOARD

(by R.

C. Flemal):

This matter comes before the Board upon

a December

26,

1985

joint petition filed by the City of Morton (“Morton”)

and

the

Illinois Environmental Protection Agency (“Agency”).

The

petition seeks exception to 35

Ill. Adm. Code 306.305(b)

(treatment of overflows and bypasses)

as

it applies

to Morton’s

existing combined sewer overflow (“CSO”) facilities and one of

its sewage treatment plants.

Hearing was held March 31,

1986,

at the Morton Village

Hall.

At hearing the Joint Petitioners amended their request to

include exception

from 35

Ill. Adm. Code 306.305(a)

as this

section relates

to treatment requirements of the first flush of

storm

flows

(R at

51; Ex.

N).

CSO REGULATIONS

The CSO regulations are contained

in

35 Iii.

Adm. Code,

Subtitle

C, Chapter

I, Part 306.

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

69.417

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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 Morton has

done.

A joint petition may seek an exception based

on minimal

discharge impact

as provided

in Section 306.361(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 unnatur~lbottom deposits, odors,

unnatural floating material or color,

stream morphology

and results of limited stream chemical analyses.

Pursuant

to 306.361(a) Morton and the Agency assert that

overflows from its combined storm and sanitary sewer system have

minimal impact on the water quality of, and do not restrict the

use of,

Prairie Creek

(the receiving stream).

BACKGROUND

Morton has

a population of 14,200, and is located

in

Tazewell County along Interstate

74 approximately 10 miles east

of Peoria and

30 miles west of Bloomington.

Petitioner owns and

operates two sewage treatment plants,

referred to as Plants

2 and

3.

These plants serve the southern and northern portions of

Morton, respectively.

The service area of Plant

3 does not

contain any combined sewers,

so is not directly related to

Morton ‘s petition.

Plant

2 is designed to treat an average flow of 2.4 million

gallons per day

(mgd) and to give complete treatment to

a peak

flow of 6.0 mgd.

All flows

in excess of 6.0 mgd are bypassed

after passing through a coarse

(3-inch) bar screen.

Bypassing

occurs either by gravity through a 30-inch gravity bypass

(if the

stage of Prairie Creek permits), or by pumping at the excess flow

pump station located at the facility.

This bypass

is designated

as outfall 002.

69.418

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—3-

As

is the case with many Midwestern communities,

older sewer

lines in Morton were often constructed as combined sewers.

Morton has,

since

1980, undertaken

a program to separate many of

the combined sewer lines

(Ex.

C and D).

Morton has also

significantly increased interceptor capacity, thereby allowing

diversion of combined sewer flow to Plant

2

for treatment.

Over

the period 1980 to date these efforts have allowed Morton

to

eliminate eight CSOs

(R.

at

8).

In combination with other

programs, including improvements to the hydraulic capacity of

Prairie Creek, Morton has spent approximately $3 million to date

designed at least in part to reduce

CSO impacts

(R.

at

4).

Petitioners contend that additional improvements needed to come

into complete compliance with CSO regulations would cost a

minimum of $1,101,000,

and would produce little environmental

benefit

(Joint Petition,

p.

1,

7).

In addition to the Plant

2 bypass, Morton presently has two

remaining CSOs.

These, designated as outfalls 011 and 015, are

both located within the central commercial section of Morton

where separation of sewers

has been most difficult.

Nevertheless,

as

a condition to granting of the requested

exception, Morton has agreed to eliminate overflow 015.

Thus,

the requested exception relates only to the plant bypass CSO

outfall 002,

to outfall Oil,

and to outfall 015 during

its

remaining period of service.

In addition to eliminating pverflow 015, Morton proposes,

as

conditions to granting of the requested exception, to undertake

several improvement projects.

These include provision of primary

treatment and chlorination plus flow measurement and sampling of

all flows bypassed through outfall 002; reduction of overflows

at

outfall 011 by separation of additional areas of combined sewer

area tributary to 011; elimination of the possibility of solids

deposition downstream of outfall 011 by modifying the channel of

Prairie Creek; and, elimination of the possibility of back-up

into overflows 011 and 015 by installation of appropriate control

structures.

Morton also agrees to monitor the excess

flow

facilities and, should

a swirl concentrator be employed as part

of the improvements program,

to provide an engineering study of

the effectiveness of the concentrator.

DOCUMENTATION OF MINIMAL I~MPACT

The Village of Morton is located at,

and the CSOs at issue

herein discharge

to,

the headwaters

of Prairie Creek.

Throughout

the reach in question Prairie Creek

is an intermittent stream,

with the principal discharge derived from runoff and groundwater

infiltration within Morton itself.

For these reasons CSO events

tend to occur concurrently with high flows

in Prairie Creek.

A

modeling study conducted by Morton indicates that for a one-year

three-hour

storm CSO 011 would contribute approximately 17

of

the flow in Prairie Creek at the point of discharge and

approximately 11

downstream beyond the developed area of Morton

CR.

at

21).

Similarly,

bypass 002 would contribute

10

of the

69.419

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—4-

flow of Prairie

Creek at

the point of discharge, but this would

decrease to

4

immediately downstream due to the addition of a

large tributary

(R.

at

22).

There are no impoundments on Prairie Creek;

points of public

access are limited to road crossings; for significant periods

during the year there is virtually no flow.

As such,

there

is

little recreational use of the stream and virtually no fishing

activities

(Ex.

E, p.

14).

Prairie Creek joins the Mackinaw

River approximately 10 miles south of Plant

2; the Mackinaw is

fished

(Ex.

E,

p.

18).

Petitioners believe that the first

location where Morton’s effluent might affect

a drinking water

supply

is more than

100 miles downstream at Alton,

Illinois,

on

the Mississippi River

(Ex.

E,

p. 18).

Stream side land use varies along the reaches

in question.

For the initial 3500 feet downstream from outfalls 011 and 015

the adjacent land

is

zoned residential.

The next 3300 feet

is

currently

in agricultural use, but could potentially develop as

residential.

Thereafter, and including the point of outfall 002,

adjacent land use is agricultural (Ex.

E,

p.

18).

Modeling studies have been undertaken by Morton to estimate

the number of overflow events which can be anticipated annually

from outfalls 011 and 015.

These are

29 and

6, respectively

(R.

at

36).

The frequency of bypassing through 002 is less certain,

but

is anticipated

to be similar to that experienced during the

first nine months of 1985 when three events, each of

several days

duration, occurred

CR.

at

11;

Ex.

E,

p.

23).

Bypassing

experienced

in 1983 and 1984 showed

a pattern similar to that

experienced

in

1985

(Ex. 0).

Several stream inspections have been undertaken.

The most

recently reported occurred on October

18,

1985, and

is detailed

in Exhibit

E

(p.

16-17).

No unnatural bottom deposits, odors,

unnatural floating materials,

or colors were noted to occur

within the inspected

areas of outfalls 011 and 015 or of the

bypass outfall 002.

However,

at hearing Mr.

James C. Roth,

engineering consultant to Morton,

indicated that he has

occasionally seen sludge deposits and floatable materials

downstream from outfall Oil

(R.

at

27,

46).

Through much of the residential sections of Morton the

channel of Prairie Creek has been modified, including sections

which have been paved.

In the paved sections the channel

averages 20 feet

in width and has

a bank height of

8 to

12

feet.

In the relatively natural sections the channel width

averages

10 feet and the bank heights average

5 to

8 feet

(Ex.

E,

p.

17).

Most available chemical analyses on the CSOs and on Prairie

Creek were made early

in the program of work on

CSO

reductions.

Much dates back to

1980.

Therefore,

these data reflect the

overflow and interception facilities as then existent.

The

69-420

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—5—

substantial configuration changes subsequently made, including

the reduction

in CSO tributary areas and number of outfalls, plus

the increase in interceptor capacity,

have all been in the

direction of lessening impact.

Even with this perspective,

analyses of biochemical oxygen demand

(BOD) and total suspended

solids

(TSS)

in outfall 011 made

in 1980 indicate low

concentrations.

Petitioners conclude that high BOD wastes either

are not deposited

in the sewers to be scoured by high flows

resulting

from runoff,

or are intercepted and diverted to Plant

2

in the early part of an event before overflow occurs

(R.

at 8).

Elevated TSS concentrations, however, do occur in the CSO

discharge.

Petitioners believe that the majority of TSS loads

comes from the storm sewer component of the combined sewers,

and

that they do not differ appreciably from the TSS loadings

in the

separate storm sewers

(Ex.

E,

p.

24).

Some sampling of the water quality of Prairie Creek

in the

vicinity of outfall 002 has been undertaken by Morton as required

by their

NPDES permit.

These samples

show no water quality

problems

(Ex.

E,

p.

20).

Similarly,

analyses of water quality at

the nearest downstream ambient water quality monitoring station,

which

is located on the Mackinaw River near South

Pekin,

indicates minimum or no water quality problems

(Ex.

E, p.

19).

The principal industries which discharge to the Morton

system conduct pretreatment of their wastes.

Additionally,

a

review of Plant

2 influent, effluent, and sludge data indicates

that industrial waste loads are not significant and have not

caused any treatment problems

or upsets.

Therefore,

Petitioners

conclude that no problems are expected from industrial wastes

in

the Plant bypass 002

(Ex.

E,

p.

15).

•ISSUE0F~THE.FIRST~~FLUSH

Joint Petitioners originally requested exception only from

the provisions of 306.305(b),

and not from the first

flush

provision of 306.305(a).

This position was based on the belief

that the interceptor sewer configuration would allow all of the

first flush to be routed to Plant

2, and that the 6.0 mgd maximum

capacity of the plant would allow complete treatment of the first

flush.

Later reflection combined with uncertainties regarding

the ability to calculate first flush has

led Petitioners to

reconsider this position.

Although it is still considered to be

highly probable that first

flush will be treated

in its entirety

CR. at 22,

54), Petitioners desire exception from the first flush

provision as protection against the possibility that some portion

of the first flush under some circumstances would bypass the

treatment plant or be discharged through outfall 011.

SUMMARY

In view of the above,

the Board determines that granting of

exception to the first flush provision of

35

Ill. Adm.

Code

3O6.305(a)

and to 35 Ill. Adm. Code 306.305(b) would produce

69.421

---

—6—

minimal discharge impact pursuant to the provisions of

35

Ill.

Adm.

Code 306.361(a).

Accordingly, the requested exception shall

be granted with the conditions proposed by the Joint Petitioners.

The Board notes that the Agency has emphasized that its

support

of the Joint Petition is predicated on the assumption

that the relief

is restricted only to those substantive

requirements for effluent treatment of CSOs,

and not to relief

from water quality standards

CR. at 52).

Morton appears to have

been aware of this condition,

and has not objected to it.

The

Board itself notes that up to the present time,

the United States

Environmental Protection Agency has indicated that only variance

(i.e.

non-permanent) relief from water quality standards can be

granted consistent with the Clean Water Act

(see document

entitled

“Status Report on Discussions with USEPA”,

dated October

4,

1985; this document is part of the record

of, and

is cited

in,

Borden. Chemical• Company. v...Illinois. Environmental Protection

Kgency,

PCB 82—82,

PCB

December

5,

1985).

To assure

that this issue is clear,

the Board will introduce into the

Order,

as

proposed by Petitioners, language identifying the scope

of the exception as granted.

ORDER

1.

The Village of Morton

(Village)

is hereby granted an

exception from the treatment requirements of 35

Ill. Adm. Code

306.305(a),

as such provision relates to first

flush of storm

flows,

and to 35

Ill. Adm.

Cod 306.305(b),

for discharges into

Prairie Creek,

subject to the following conditions:

a.

The Village shall provide excess flow treatment at

Plant

2 for all excess

flows reaching the plant,

consisting of primary treatment followed by

chlorine contact, including flow measurement and

sampling, by September

30,

1988.

b.

The Village shall eliminate overflow 015 by

constructing storm sewers to separate the sewers

tributary to the overflow.

The completion date is

subject to IDOT/Morton Joint Project.

c.

The Village shall reduce overflows

from outfall

Oil by additional separation of storm and sanitary

sewers,

resulting

in

a remaining combined sewer

area of 106.2 acres, by October,

1991.

d.

The Village shall provide Prairie Creek channel

improvements to eliminate the possibillity of

solids deposition downstream of overflow 011 and

convey the overflows to

a point downstream of the

developed area of the Village by October, 1992.

69.422

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-7—

e.

The Village shall eliminate the possibility of

Prairie Creek back-up into overflows Oil and 015

by September,

1986.

f.

The Village shall collect data and monitor the

excess flow treatment facilities.

If a swirl

concentrator

is used,

an engineering evaluation as

to its effectiveness compared with that of a more

conventional primary clarifier should be submitted

to IEPA within one year after

items

a), b), c),

and e) have all been completed and the system has

been in operation.

2.

This grant

of exception does not preclude the Agency

from

exercising

its

authority

to

require

as

a

permit

condition

a)

a

CSO

monitoring

program

sufficient

to

assess

compliance

with

this

exception

and

any

other

Board

regulations,

including

Section

306.305(c);

and b) other controls

if needed for compliance,

including compliance with water quality standards.

3.

This grant

of exception

is not to be construed

as

affecting the enforceability of any provisions of this exception,

other

Board regulations,

or the Act.

4.

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

Village 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 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 85-212

dated May 9,

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

69-423

---

—8—

IT IS SO ORDERED.

Board

Members Joan Anderson, Jacob

D. Dumelle and Bill

Forcade concurred.

I,

Dorothy M. Gunn, Clerk of the Illinois Pollution Control

Board, hereby certify that the above Opinion and

Order was

adopted on the

...

day of

~

,

1986,

by a vote

of

____________.

~/TL~c~

~

Dorothy

M. Cu

n,

Clerk

Illinois Pollution Control

Board