ILLINOIS POLLUTION CONTROL BOARD

August 14, 1986

MOBIL OIL COMPANY,

Petitioner,

V.

)

PCB 86—45

ILLINOIS ENVIRONMENTAL PROTECTION

)

AGENCY,

Respondent.

EUGENE W.

BEELER, JR.

AND ARTHUR G. HOFMANN APPEARED ON BEHALF OF

THE PETITIONER;

THOMAS DAVIS APPEARED ON BEHALF OF THE RESPONDENT.

OPINION

AND

ORDER OF THE BOARD

(by J. Marlin):

On March

31, 1986

Mobil Oil Company (Mobil)

filed a petition

for variance extension from 35 Ill. Adm. Code 304.122 as

it

relates

to the

3.0 mg/i ammonia nitrogen standard applicable to

Mobil’s Joliet Refinery’s discharge into the Des Plaines River.

Mobil waived hearing.

Citizen objections

to the variance and a

request for hearing were filed on April

24 and April 26.

A Board

order

of May 9, 1986,

addressed the citizen filings and ordered

that a hearing

be held

in

this matter.

On May 6,

the Illinois

Environmental Protection Agency

(Agency) filed

a recommendation

that the variance request

be granted,

but with some modifica-

tion.

Mobil filed

a response to the Agency Recommendation on May

9.

The Agency filed a motion

to amend

its Recommendation on June

26, 1986.

That motion

is granted.

Hearing was held on July 15,

1986.

On July 30, Mobil

filed a motion for leave

to file a

compilation of materials

to be incorporated by reference.

That

motion

is also granted.

Mobil owns and operates

a conventional fuels petroleum

refinery with

a rated capacity of 180,000 barrels per day located

in Will County.

The refinery discharges 2.74 million gallons of

effluent ~er day.

Stormwater,

noncontact cooling water and

process water are discharged from the facility into the Des

Plairies River.

The process water

and contaminated surface runoff

(1600 gpm) are treated

in Mobil’s wastewater treatment plant

(WWTP) which consists of an API separator,

a dissolved air

flotation unit,

an equilization basin for primary treatment and

a

conventional activated sludge facility for secondary treatment.

Treated effluent from the final clarifier

is

routed through a

4.98 million gallon guard basin where

it

is retained for

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approximately 51 hours and then aerated in the final

aeration

cone prior

to release

to the Des Plaines River.

The effluent

meets all discharge standards other than ammonia nitrogen.

Mobil has been granted five previous variances from the

ammonia nitrogen standard of Section 304.122 (old Rule 406,

Chapter

3):

(PCB 77—22, PCB 78—97, PCB 80—54, PCB 82—36 and PCB

84—37.

In PCB 84—37, 60 PCB 97, Sept.

20, 1984, variance was

granted until July 1, 1986 subject

to certain conditions,

including an ammonia nitrogen effluent limitation of

25 mg/i

monthly average and

35 mg/i daily maximum concentration.

In the present petition,

Mobil requests an ammonia nitrogen

effluent limitation of 25 mg/i monthly average and 40 mg/i

daily

maximum concentration until final action

is

taken on its site

specific regulatory proposal, R84—l6

(Pet, at

8).

The Agency

recommends standards of

5 mg/i annual average, 10 mg/l monthly

average and 30 mg/I daily maximum.

In the past 13 years, Mobil

has expended considerable time

and effort

in

its attempt

to reach ultimate compliance with the

ammonia standards.

The total cost of ammonia

related capital

expenditures is

in excess of $2.1 million (Pet. at

3).

The

average annual operating cost for

ammonia reduction projects

during the last five years has been $1,801,000,

including

amortization of capital investments

(Pet. Table 2).

Equalization

system improvements and continuous dissolved oxygen monitoring

in

the aeration basins cost an additional

$64,000 between 1982 and

1985

(Pet,

at 3).

Projects have included the purchase and

installation of

a nitrification pilot plant,

nitrification

inhibition studies, mutant bacteria trials, alkalinity addition

and temperature control

in the aeration basins.

Since

1973,

these efforts have reduced Mobil’s discharged ammonia

concentration by 96 percent

(Id).

In 1973, Mobil’s discharge averaged 77 mg/l ammonia

nitrogen.

In 1979 and 1980

it averaged

13 and 17 mg/i,

respectively.

During 1984 and 1985,

the average was down

to

3

mg/i

(Pet. Table 1).

Reports filed August

7, 1986,

as part of

the R84—l6

record,

indicate that the monthly averages for the

first

six months of 1986 range from

7 mg/I

in January to zero

in

March and June.

The daily maximum range

is from

0

to 16.

Mobil contends the requested monthly average limitations of

25 mg/i and daily average limitations of 40 mg/i are justified

because the waste water treatment plant

can experience

variability in ammonia loading due

to the nitrogen content of

crude oil and

in ammonia discharge due

to nitrification

inhibition.

During periods when the biological treatment system

is out of service for repair

or maintenance, nitrification

capability

is greatly reduced.

(The Board notes

that a

provisional variance may be appropriate at such times.)

Mobil

also points out that the 40 mg/i maximum was exceeded twice

during

the previous variance period

(Pet,

at

7).

The Agency

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believes

that the presently achievable performance supports more

stringent levels than those requested (Agency

rec.

at 2).

Mobil contends that the ammonia content of the crude oil

available to Midwestern refineries has been increasing as sources

shift from the oil fields of the Middle East.

Mobil asserts that

this increase will make

it more difficult to achieve consistently

low levels in the effluent

(R84—l6 transcript,

pp.

22—36; exhibit

1, exhibit lA).

The crude

oil nitrogen content at the Joiiet

refinery has gone from

a

low of about 680 ppm in 1976 to

a high

of about 1450 ppm in

1984.

In 1985

it was down

to roughly 1120

ppm (figure attached

to petition).

Both Mobil

and the Agency agree that the effect of the

ammonia loading

to the river at levels

in excess of the standard

would

be

a minute increase

in the river ammonia concentration,

and accordingly that the environmental effects

of grant of

variance would

be minimal.

The Board concurs in this belief,

as

it has

in granting previous variances, but particularly since

Mobil’s discharges

in i984 and 1985 on an average meet the

standard,

although excursions continue to occur.

The Board previously found

that denial of variance would

result

in an arbitrary or unreasonable hardship “given that

technically and economically feasible means

of meeting the

standard have not been

identified despite Mobil’s diligent

efforts”

(60 PCB at

99).

The Board again

so finds, noting that

since

that time, Mobil

has continued

its efforts at achieving

compliance and has further improved its effluent quality.

The Board will accordingly grant variance beginning July 1,

1986 for

a period

of two years,

or until final action is taken in

R86—i6, whichever first occurs.

While the Board would anticipate

taking such final action long before expiration of

the variance

period,

the Board chooses this term to allow sufficient time to

accomodate unforeseen contingencies.

The variance term begins on

July 1, 1986 in

recognition of

the fact that the variance

petition was timely filed

90 days before expiration of the prior

variance, of Mobil’s diligent pursuit of its case

in both this

and the site specific action,

and of its continuing compliance

efforts.

As to the limitations and conditions

of variance, the Agency

correctly asserts that the Joliet refinery has produced high

quality effluent during the past two years.

The Board, however,

does not presently find this to be sufficient reason

to tighten

the effluent limitations during the short life of the variance,

and will impose

the daily and monthly limits contained

in the

prior variance.

Mobil

has pointed out circumstances which

could

lead

to exceedances of

the current limitations.

Mobil has made

admirable progress

in reducing its ammonia nitrogen discharge,

and there

is no reason

to believe

it will lessen its control

72-35

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—4—

efforts during the period

of this variance.

However, the Board

will emphasize

that its choice of these higher limits is not

to

be construed

as authorization for “backsliding”.

The Board will reevaluate the daily and monthly effluent

limitations while reaching

a decision in R84—l6;

today’s action

is not

to be construed as

a predetermination of the outcome of

that proceeding.

The Board will additionally consider the issue

of what,

if

any,

annual limitation should be imposed in R84—l6,

and will not impose one

as

a condition of this variance.

This Opinion constitutes

the Board’s findings of fact and

conclusions of law in this matter.

ORDER

1)

Mobil Oil Corporation

is hereby granted

a variance from 35

Ill.

Adm. Code 304.122

for discharges from its Joliet Refinery,

beginning July 1, 1986 and terminating July 1, 1988,

or

at such

earlier

time as

the Board takes final action in R84—16,

subject

to the following conditions:

A)

Mobil’s ammonia nitrogen effluent discharge shall not

exceed a monthly average concentration of 25 mg/i and

a

daily maximum concentration of

35 mg/i during the

period of this variance.

Mobil

shall,

however,

to the

extent practicable,

continue its efforts

to produce

effluent which complies with the limitations of Section

304 .122.

B)

Mobil

shall continue its research aimed at complying

with the ammonia nitrogen standard and shall continue

to submit bi—monthly reports

to the Agency outlining

its efforts to achieve compliance with 35

Ill. Adm.

Code 304.122, including any studies on nitrification

inhibition,

alkalinity addition and any further pilot

plant

testing.

2)

Within

45 days

of the date of this Order, Mobil

shall

execute and forward

to the Illinois Environmental Protection

Agency, Compliance Assurance Unit, Water Pollution Control

Division, 2200 Churchill Road, Springfield, Illinois

62706,

a

Certification of Acceptance and Agreement to

be bound

to all

terms

and conditions set forth in the Order.

The 45 day period

shall

be held in abeyance during any period

in which

this matter

is being appealed.

The form shall

be as shown

below:

CERTI FICATION

I,

(We),

_____________________,

hereby accept and agree

to

be bound by the above terms and conditions of the Order

of the

Pollution Control Board

in PCB 86—45 dated August 14, 1986.

72-36

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—5—

Petitioner

By:

Authorized Agent

Title

Date

IT

IS SO ORDERED.

I, Dorothy M.

Gunn,

Clerk

of the Illinois Pollution Control

Board, hereby certify that the above Opinion and Order was

adopted

on the

/~ttZ~ day

of

_________________,

1986

by

a vote

of

__________.

~Dorothy M. dunn, Clerk

Illinois Pollution Control Board

72-37