ILLINOIS POLLUTION CONTROL BOARD

April

10,

1975

CENTRAL

DU PAGE HOSPITAL ASSOCIATION,

Petitioner,

v.

)

PCB 74—364

ENVIRONMENTAL PROTECTION AGENCY,

Respondent.

SUPPLEMENTAL OPINION AND ORDER

OF THE BOARD

(by Mr.

Dumelle)

This

Opinion and Order supplements the pr~viously

issued Order of the Board, dated November 22,

1974, and

Interim Opinion of the Board,

dated January

9,

1975.

The case concerns a Petition for Variance filed on

October

9,

1974 by Central DuPage Hospital Association

(Hospital)

located in the Village of Winfield in DuPage

County.

The relief sought

is from Sections

12 and

39

of the

Environmental Protection Act and Rule 927 of Chapter

3:

Water Pollution Regulations to allow the Hospital to connect

its planned 112-bed hospital addition to the Village of

Winfield Sewage Treatment Plant.

On November 22,

1974 the Board issued its Order granting

the variance to the Hospital but required the following from

the parties:

“2.

Within 60 days of the date of

this order, petitioner

shall provide

a study of the condition of the receiving

stream

(as regards water quality)

below the Winfield Sewage

Treatment Plant and the environmental effects

(especially

those resulting from plant bypassing)

expected from the

grant of this variance.

“3.

The Agency shall comment upon the petitioner’s

response to the Board within 10 days after receipt.

“4.

The Board shall retain jurisdiction in this case

to consider the possible requirement for holding tanks.

The

report and comments shall also be directed toward consideration

as to the necessity and feasibility for holding tanks.”

Responses to the Board’s Order of November

22,

1974

were received from the Petitioner and from the Agency.

The

Agency filed, on December

23,

1974,

an Amendment to Recommenda-

tion which contained results of two stream biological surveys

16

—365

---

—2—

conducted

on the DuPage River

-

West Branch to assess

the

environmental

impact of

the Winfield Sewage Treatment Plant.

These surveys were conducted on December

4,

1974

and September

4—5,

1973

at

4 locations upstream and downstream

of the

Winfield Sewage Treatment Plant outfall,

and

the environmental

quality of

the river and

the marsh

that, receives

the

sewage

treatment plant effluent was assessed.

The results and

their significance are

as follows:

DATE

LOCATION

STREAM

CLASSIFICATION

BIOLOGICAL SPECIES

SIGNIFICANCE

9/4/7 3

West Branch

-

1.5

miles upstream from

sewage treatment plant

outfall

balanced

Intolerant

organisms

are many in number and

species,

or more

in

number

than other forms

present.

9/4/7 3

Marsh

-

20 yards

“downstream”

from

sewage treatment plant

outfall.

polluted

Intolerant forms are

absent.

Only tolerant

forms

are

present

or

no organisms

present.

9/5/73

Marsh

—

outlet

channel

to West

Branch.

semi—polluted

Intolerant

organisms

are

few

or may not be

present.

Moderate or

facultative organisms

may be present.

9/5/7

3

West Branch

-

100 yards downstream

from Marsh outlet

channel.

balanced

See above.

12/5/74

West Branch

-

1.5 miles upstream

from sewage treatment

plant outfall.

unbalanced

Intolerant organisms are

fewer in number than

other forms combined,

but

combined with moderate

forms, they usually

outnumber tolerant forms.

12/5/74

Marsh

-

20 yards

“downstream”

from

sewage treatment plant

outfall.

polluted

See

above.

12/5/74

Marsh

-

outlet

channel to West

Branch.

semi—polluted.

See above.

12/5/74

West Branch

-

100

yards downstream from

marsh outlet channel.

unbalanced.

See above.

16—366

---

—3—

Based on this work,

the West Branch at

a

point 100 yards

downstream from the marsh outlet channel has approximately

the same biological quality as it does 1.5 miles upstream of

the Winfield Sewage Treatment Plant.

The Petitioner filed

its study entitled “Anticipated

Water Quality Effects on the West Branch DuPage River Resulting

from a Planned Expansion of the Central DuPage Hospital” on

January

22,

1975.

The study discusses the Winfield Sewage

Treatment Plant, estimates the additional wastewater load to

be generated by the hospital ac~c3ition, assesses the present

water quality of the West Bran~hupstream and downstream of

the Winfield Sewage Treatment Plant input, and estimates the

impact on the stream of the hospital addition.

The study

also discusses the benefits and costs of a wastewater holding

tank at the hospital.

The Winfield Sewage Treatment Plant consists of a

contact stabilization plant of 0.5 MGD design capacity

followed by

a two polishing ponds in series having a total

volume of

3.2 million gallons.

The raw sewage pumping

capacity is 4.04 MCD.

Influent flows to the plant in excess

of the 0.5 MGD contact stabilization capacity are bypassed

to the polishing ponds.

At present the plant is hydraulically

overloaded

in that the 1974 average flow was 1.34 MGD.

By-

passing of the contact stabilization unit occurred on

67

days in 1974.

Average influent concentrations

in 1974 were

56 mg/l

(626 lb/day)

of BOD and 83 mg/l

(928 lb/day) of SS.

The sewage treatment plant effluent contained an average of

5.9 mg/l of BOD and 51 mg/l of SS in 1974,

the average BOD

and SS removal efficiencies being 89

and 39,

respectively.

Petitioner

now estimates that wastewater will be

generated by the 112-bed hospital addition at a rate of

22,400 gal/day

(0.022 MGD)

and will contain 24.6 lbs/day of

BOD and 29.1 lbs/day of

SS.

This additional flow represents

a 1.6

increase in flow,

a 3.9

increase in BOD, and a

3.1

increase in SS to the Winfield Sewage Treatment Plant.

The DuPage River

-

West Branch near Winfield has a 7-

day once-in--lU-year low flow of

3.9 MCD.

Water quality

surveys

taken by the Agency and by Petitioner’s engineers

show little effect of the Winfield Sewage Treatment Plant on

water quality.

The additional

flow of 0.022 MCD generated

by the hospital addition represents

a 0.6

increase in

stream flow during dry weather.

During wet weather, when

bypassing of the contact stabilization unit occurs,

the

stream flow

is higher so that more dilution is available.

The Petitioner sized

a wastewater holding tank at

16—367

---

—4—

22,400 gallons,

sufficient

to hold one day’s generated

waste.

The tank would include an air system to prevent

septic conditions and solids settling and a

lift station to

control the discharge to the sewer system.

The capital

cost,

including engineering,

contingencies,

overhead,

and

profit

is estimated

to be $35,000.

Based

on

its

study

the Petitioner

concludes

that the

additional wastewater

from

the hospital addition will

“not

cause any adverse water quality changes

in

the West Branch

DuPage River”.

Furthermore,

it concludes

that

a holding

tank

is not recommended because “adverse factors such as

possible odor problems,

septic sewage,

operation and maintenance

problems

and costs,

outweigh

the unlikely possibility

of

improving water

quality

of

the effluent

at the Winfield

Sewage Treatment Plant’.

On February

19,

1975

the Agency submitted

its comments

entitled

“Response of the Environmental

Protection Agency.

The Agency agrees with

the Petitioner’s study and conclusions.

The Board concludes

from

the above information

that

a

holding tank

is not necessary

in this instance.

Although

sewage does bypass the contact stabilization unit,

it still

undergoes some treatment in the polishing ponds, and in fact

the BOD was reduced to 5.9 mg/l

in

the effluent in 1974.

The retention time in the ponds

is at least

25 hours and

ranges up to 136 hours based on 1974 monthly average flows.

This Opinion constitutes the Board’s findings of

fact

and conclusions of law.

ORDER

Petitioner, Central DuPage Hospital Association,

is not

required to install sewage holding

tanks.

IT IS SO ORDERED.

I, Christan L. Moffett, Clerk of the Illinois Pollution

Control Board, hereby certify the above Opinion and Order were

ad pted on the

/~t’~

day of April, 1975 by a vote of

-D

___

C ristan L. Mo

e

er

Illinois Pollution

ntrol Board