ILLINOIS POLLUTION CONTROL BOARD

April 19,

1984

CITY OF MATTOON,

)

Petitioner,

)

v.

)

 PCB 84—47

)

ILLINOIS

 ENVIRONMENTAL

)

PROTECTION AGENCY,

)

Respondent.

OPINION AND ORDER OF THE BOARD

 (by W.

 J. Nega):

This provisional variance request comes before the Board

upon an April 19,

 1984 Recommendation of the Illinois Environ-

mental Protection Agency (Agency).

 The Agency recommends that a

45-day provisional variance be granted to the City of Mattoon

(Mattoon) from 35 Ill. Mm.

 Code 304.120(c) and 35

 Ill. Adm. Code

304.141(a)

 to allow higher levels of biochemical oxygen demand

(BOD) and suspended solids

 (SS)

 in the effluent discharged from

the Petitioner’s wastewater treatment plant

 (WwTP) during the

time that its tertiary sand filters are removed from service for

upgrading and rehabilitation.

The Petitioner owns and operates a wastewater treatment

facility which has a design average flow of 4.5 million gallons

per day (MCD).

 Mattoon’s WWTP has treatment units which include

pumping, primary settling, grit removal, activated sludge process,

secondary settling, chlorination, treated storm overflow, sludge

digestion and drying, and tertiary sand filters.

 (Rec.

2).

The proposed work to be done on the tertiary sand filters

includes:

(1)

 replacement of the butterfly valves;

 (2) installation

of a new low pressure air diffusion system;

 (3) partial replacement

and cleaning of the underdrain mesh;

 (4) cleaning of the clearwell;

and

 (5) installation of a new chemical cleaning system.

 (Rec.

2).

Because some of the butterfly valves and piping are at, or

below, water level and the clearwell needs to be drained in order

to clean it, the only feasible method of performing this work is

to temporarily remove the sand filters from service.

 (Rec.

2).

The Petitioner contends, and the Agency agrees with the Petitioner,

that this procedure is the best method for upgrading and rehabili-

tating the sand filters and rapidly getting these filters back

into service.

 (Rec.

2).

57-441

—2—

Mattoon has experienced various problems with its sand

filters since at least October,

 1983.

 (Rec.

3).

 Since that

time,

 the Petitioner has reported the following levels for BOD

and SS on its discharge monitoring reports to the Agency:

BOD

SB

Month

 Flow

 (MGD)

 Avg.

 (mg/i)

 Max.(mg/l)

 Avg.

 (mg/i)

 Max.

 (mg/i)

October,

1983

5.4

10

14

17

21

November, 1983

7.3

9

11

17

19

December, 1983

8.2

8

9

15

22

January,

1984

5.3

10

11

15

18

February,

1984

7.4

9

12

13

16

Average

6.7

9

11

15

19

According to the Agency’s field personnel, Mattoon’s

WWTP

is

currently able to process only one to two MCD through its ter-

tiary sand filters.

 (Rec.

3).

 However, as indicated

 in the

above table, the Petitioner is still able to meet its NPDES

Permit limits with some excursions

 in SS even though most of the

flow is bypassing the filters.

 (Rec.

3).

 Mattoon’s effluent

limitations as set forth in NPDES Permit No. 1L0029831 are

 10 mg/i

BOD and 12 mg/i

 SS as

 30 day averages, and 25 mg/i BOD and 30 mg/i

SS as daily maximums.

 (Rec.

3).

The Petitioner has indicated that

 it does not expect any

adverse environmental impact to be caused by a small increase in

BOD and SS levels in the effluent during the time period of the

requested provisional variance because of the high stream flows

during this part of the year.

 Mattoon intends to operate all

portions of its WWTP except the tertiary sand filters during the

period when the filters are being upgraded.

 (Rec.

3).

The Agency believes that the provisional variance is appro-

priate because

 it will allow the Petitioner an opportunity to

correct the problems previously experienced with the sand filters

and will have a minimal environmental impact on the receiving

stream due to the high stream flows and the quality of the effluent

discharged from Mattoon’s WWTP.

 (Rec.

3).

 Accordingly, the

Agency believes that the denial of the provisional variance would

impose an arbitrary or unreasonable hardship on the City of

Mattoon.

Thus,

 the Agency recommends that the Board grant the City of

Mattoon

 a 45-day provisional variance from Sections 304.120(c)

and

 304,141(a),

 subject to certain conditions.

 Pursuant to

Section

 35(b) of the Illinois Environmental Protection Act, the

Board hereby grants the provisional variance as recommended.

57-442

—3—

ORDER

The City of Mattoon is hereby granted a provisional variance

from 35 Ill, Mm. Code 304.120(c) and 35 Ill. Adm. Code 304.141(a)

for a period of 45 days to begin on April

19,

 1984 to allow

higher levels of BOD and SS in the effluent discharged from the

 Petitioner’s wastewater treatment plant during the time that its

tertiary sand filters are removed from service for upgrading and

rehabilitation,

 subject to the following conditions:

1.

 The Petitioner shall meet the effluent limitations as

given below:

30 day avg.

 daily max.

BOD

 20 mg/l

 30 mg/i

sS

 25 mg/i

 37 mg/i

The frequency of sampling and testing shall remain as

in NPDES Permit #1L0029831.

2.

 Work on the sand filters shall continue as expeditiously

as possible so that the sand filters will be returned to

service as soon as possible.

3.

 The Petitioner shall notify Roger Cruse of the Agency’s

Compliance Assurance Section by telephone at 217/782—9720 of

any violations of the above effluent limits.

 Such notification

shall be followed by written notification sent to Robert Cruse

at the address indicated below.

4.

 The Petitioner shall notify Roger Cruse by telephone at

217/782—9720 when the work on the sand filters is completed

and when the sand filters are placed back in service.

 Such

notification(s)

 shall be followed by written notification(s)

sent to Roger Cruse at the address indicated below.

5.

 During the period of this variance, the Petitioner

shall operate and maintain the wastewater treatment facility

(with

 the exception of the tertiary sand filters)

 so as to

achieve the best quality of effluent possible.

 If the work to the sand filters is accomplished in less

than 45 days,

 this variance shall expire when the work to

the sand filters is completed and they are placed back in

service,

7.

 Within 10 days of the date of the Board’s Order, the

City of Mattoon shall execute a Certificate of Acceptance

and Agreement which shall

 be sent to:

 Illinois Environmental

Protection Agency, Division of Water Pollution Control,

 Corn—

57-443

—4—

pliance Assurance Section, 2200 Churchill Road, Springfield,

Illinois

 62706.

 This certification shall have the follow-

ing

 form:

CERTI FICATION

I,

(We),

having

read

the Order of the Illinois Pollution Control

Board

 in PCB

84—47

dated April

19,

 1984, understand and accept the said Order, real-

izing that such acceptance renders all terms and conditions thereto

binding and enforceable.

Petitioner

By:

 Authorized Agent

Title

Date

IT IS SO ORDERED.

Christan

Moffett,

Clerk

the

Illinois

Pollution

Control Board,

hereby

~ertify

that

th~ above

Opinion

and

Order

was

 adopted on the

~day

~J,

1984

vote

Christan L. Moff~t~)Clerk

Illinois

PollutioI1~Control

Board

57.444