ILLINOIS POLLUTION CONTROL BOARD

March 31,

1994

MARATHON

OIL

COMPANY,

)

Petitioner,

v.

)

 PCB 92—166

)

 (Permit Appeal)

ILLINOIS ENVIRONMENTAL

PROTECTION AGENCY,

Respondent.

JOSEPH W. WRIGHT, OF MCBRIDE

BAKER

& COLES, AND

RONALD L~ANDES

APPEARED ON BEHALF OF PETITIONER;

CHARLES

GUNNARSON

APPEARED

ON BEHALF OF RESPONDENT.

OPINION

AND

ORDER

OF THE BOARD

 (by R.

Flemal):

This matter comes before the Board upon a petition for

review filed by Marathon Oil Company

 (Marathon).

 Marathon

requests that the Board remand the National Pollutant Discharge

Elimination System (NPDES) permit issued on September 30,

 1992 by

the Illinois Environmental Protection Agency

 (Agency) for waste

water discharges from Marathon’s petroleum refinery located near

Robinson, Illinois.

 Marathon contests the manner in which

dilution/allowed mixing was utilized by the Agency in determining

discharge limits in the NPDES permit and the manner in which

toxicity provisions are expressed in the permit.

 Marathon also

raises procedural issues regarding the manner in which Marathon’s

 NPDES permit application was processed by the Agency.

The Board’s responsibility in this matter arises from the

Environmental Protection Act

 (Act)

 (415 ILCS 5/1 et seq.

 (1992).)

The Board is charged there to adjudicate disputes arising out of

permit decisions made by the Agency.

 More generally, the Board’s

responsibility in this matter is based on the system of checks

and balances integral to Illinois environmental governance:

the

Board is charged with the rulemaking and principal adjudicatory

functions, and the Agency is responsible for carrying out the

principal administrative duties,

 including the issuance of

permits.

Based on review of the record, the Board remands this matter

to the Agency for reissuance of the permit consistent with the

actual low flow conditions in the receiving stream.

—2—

PROCEDURAL HISTORY

Marathon has been issued NPDES permit No. IL0004073 covering

waste water discharges from the Robinson refinery.

 That permit’

was due to expire on August

1,

 1991.

 On January

1,

 1991 Marathon

timely filed an application for reissuance of the

permit2.

Various exchanges between Marathon and the Agency thereafter

ensued, culminating in reissuance of permit No. IL0004073 on

September 30,

 1992.

On October 29,

 1992 Marathon filed the instant appeal

 contesting the September 30,

 1992 reissuance.

The Agency filed its record in this proceeding on December

1992.

The

Agency

 record contains forty-seven individual

documents

(exhibits)

plus

 attachments, comprising 766 pages in

aggregate.

February

25,

1993

Marathon

filed

motion

supplement

the record.

 The motion was denied by Board order of March 11,

1993.

After

being

rescheduled

from

time

allow

for

settlement

discussion

and

discovery,

hearing

was

held

 before

hearing

officer

Stephen

Davis

October

27,

1993

Robinson,

Illinois.

 Marathon called three witnesses:

 Richard F.

 Bonelli,

Jr., Manager of Technical Services at Marathon’s Robinson

facility; Sandra N. Bron,

 an engineer employed in the Permit

Section of the Agency’s Division of Water Pollution Control; and

Robert G. Mosher, Unit Supervisor for Standards and Monitoring

Support in the Agency’s Division of Water Pollution Control.

The

Agency called one witness, the same Mr. Mosher.

Neither party presented either opening or summary arguments

at hearing,

 instead standing on their briefs-

Marathon’s brief was filed on December 10,

 1993.

 The Agency

filed its brief on January 10,

 1994.

 Marathon filed a reply

brief on February 15,

 1994.

At the time Marathon filed the instant appeal,

 it had two

additional actions before this Board that involve provisions of

its NPDES permit:

 a variance petition from chloride limits and a

petition to amend the site-specific rule from which the same

chloride limits flow.

 The variance petition has since been

resolved by grant of the variance, with conditions,

 for a term of

The “old permit”

 is Exh. B to the Marathon petition

 (Pet.

Exh.

B).

 The application is Exh. A to Marathon’s Petition

 (Pet.

Exh.

A)

 and Exh.

 8 of the Agency Record

 (Rec.

Exh.

8).

—3—

one year or upon completion of the site—specific rulemaking.

(Marathon v.

 IEPA, PCB 91-173,

 October

 7, 1993.)

 The site—

specific rulemaking is in first notice.

 (In re: Marathon Site-

Specific, R91—23, October 7,

 1993.)

BACKGROUND

The NPDES permit at issue here covers three separate

 effluent outfalls: 001,

 002, and 003.

 Outfall 001 carries the

discharge from Marathon’s waste water treatment plant

 (WWTP).

Outfalls 002 and 003 carry the discharge from impoundments on the

Marathon

property.

The

WWTP

treats wastes generated in operations within the

refinery.

 Marathon’s

WWTP

has had various configurations over

time

 (Tr.

 9-12).

 Most recently Marathon began operating a new

WWTP,

with

 a startup date January 1,

1993

 (Tr. at 10).

The receiving stream for the Marathon discharge is an

unnamed3 tributary of Sugar Creek.

 There are permitted point

source discharges to the unnamed tributary located upstream of

the Marathon discharge.

 Although the natural 7-day 10-year low

flow

(1Q10)

 of the unnamed tributary is zero, actual low flow at

the point of the Marathon discharge is determined by the upstream

discharges.

ISSUES AND BOARD FINDINGS

MixincilDilution

As an initial point, the Board observes that it will remand

this permit to the Agency for reissuance consistent with

admission at hearing

 (Tr. at 51—54) that the 7Q10 appropriate for

mixing/dilution considerations in this matter is 1.2 cubic feet

per second

 (cfs).

 When the permit was originally issued in

September 1992 the Agency proceeded under the assumption that the

 appropriate 1Q10 was zero4, and accordingly that no allowance for

~Although not officially named, the creek is sometimes

referred to as Robinson Creek.

~

 Each party blames the other for causing the “1Q10

 zero”

assumption to ever have had currency with the Agency.

 The Board

does not find it productive to try to sort out and assign blame.

The Board

 is perplexed however, as to how the matter could ever

have arisen as late as September 1992.

 That the actual 7Q10 was

not zero is affirmed in the instant record in documents as old as

1986 (e.g.,

 R. at 18) and has even been cited in several earlier

Board opinions concerning Marathon matters

 (e.g.,

 PCB 85-83 at 67

PCB 514, January 23,

 1986; PCB 91-173 at 129 PCB 52, January

9,

—4—

mixing could be made.

 The Agency is now apparently prepared to

entertain rewriting the permit allowing for dilution.

 Under

these circumstances remand is appropriate.

In some other cases of this nature, the Board might find

that

remand

with

the

 simple instruction to reconsider the permit

light

the

appropriate

1Q10

figure

would

sufficient

resolve

the

matter.

However,

the

instant

case

it

apparent

to the Board that the parties are sufficiently at odds that more

instruction on the issue of dilution/mixing is going to be

necessary.

Underlying the instant dispute is the concept of allowed

mixing.

 The Board discussed this concept at the time it adopted

the concept in its currently applicable form:

Today’s rules affirm a long-standing tenet of

Illinois environmental law.

 That tenet is that a

discharger unable to comply with the requirement of not

causing or contributing to water quality violations

found at 35 Ill. Adm. Code 304.105, after making every

effort to fulfill the obligations of the discharger

(see discussion below)

 and given

the

limits imposed by

the nature of the receiving water body and the

character of the outfall(s),

 is entitled to use a

limited portion of the receiving body of water to

effect mixing of

the

effluent with the receiving water.

Within this limited portion of the receiving body of

water, the discharger is excused from compliance with

304.105.

 This is the “allowed mixing concept”, which

is developed principally in Section 302.102.

 (In re:

Amendments to Title 35. Subtitle C (Toxics Controls,

R88—21(A), 107 PCB 279, January 25, 1990.)

This concept is expressed in the rules at Section 302.102(a):

a)

 Whenever a water quality standard is more

restrictive than its corresponding effluent

standard, or where there is no corresponding

effluent standard specified at 35 Ill. Adm. Code

304,

 an opportunity shall be allowed for

compliance with 35 Ill.

 Adm. Code 304.105 by

mixture of an effluent with its receiving waters,

provided the discharger has made every effort to

comply with the requirements of 35 Ill. Adm. Code

304.102.

The limiting circumstances under which allowed mixing may be

used for compliance with Section 304.105 are set out at Section

1992).

—5—

302.102(b).

 As the Board has previously noted, taken as a whole

an intent of the provisions of subsection

(b)

 is that the volume

of waters used for allowed mixing must be as small as is

practical, such as to limit impact on aquatic life, human health,

and recreation.

(~.

at 107 PCB 281.)

 Subsection

(b)

 in full

reads:

b)

 The portion, volume and area of any receiving

waters within which mixing is allowed pursuant to

subsection

(a)

shall

limited

the

following:

1)

 Mixing must be confined in an area or volume

of the receiving water no larger than the

area or volume which would result after

 incorporation of outfall design measures to

attain optimal mixing efficiency of effluent

and receiving waters.

 Such measures may

include, but are not limited to, use of

diffusers and engineered location and

configuration of discharge points.

2)

 Mixing is not allowed in waters which include

a tributary stream entrance if such mixing

occludes the tributary mouth or otherwise

restricts the movement of aquatic life into

or out of the tributary.

3)

 Mixing is not allowed in waters adjacent to

bathing beaches, bank fishing areas, boat

ramps or dockages or any other public access

area.

4)

 Mixing is not allowed in waters containing

mussel beds, endangered species habitat, fish

spawning areas,

 areas of important aquatic

life habitat, or any other natural features

vital to the well being of aquatic life in

such a manner that the maintenance of aquatic

life in the body of water as a whole would be

adversely affected.

5)

 Mixing is not allowed in waters which contain

intake structures of public or food

processing water supplies, points of

withdrawal of water for irrigation,

or

watering areas accessed by wild or domestic

animals.

6)

 Mixing must allow for a zone of passage for

aquatic life in which water quality standards

are met.

—6—

7)

 The area and volume in which mixing occurs,

alone or in combination with other areas and

volumes of mixing, must not intersect any

area or volume of any body of water in such

a

manner that the maintenance of aquatic life

in the body of water as a whole would be

adversely

affected.

8)

 The area and volume in which mixing occurs,

alone or in combination ‘with other areas and

volumes of mixing, must not contain more than

25

 of the cross—sectional area or volume of

flow of a stream except for those streams

where the dilution ratio is less than 3:1.

Mixing is not allowed in receiving waters

which have a zero minimum seven day low flow

which occurs once in ten years.

9)

 No mixing is allowed where the water quality

standard for the constituent in question is

already violated in the receiving water.

10)

 No body of water may be used totally for

mixing of a single outfall or combination of

outfalls.

11)

 Single sources of effluents which have more

than one outfall shall be limited to a total

area and volume of mixing no larger than that

allowable if a single outfall were used.

12)

 The area and volume in which mixing occurs

must be as small as is practicable under the

limitations prescribed in this subsection,

and in no circumstances may the mixing

encompass a surface area larget~than’ 26

 acres.

A principal source of dispute between Marathon and the

Agency focuses on the consequence of applying subsection

 (b) (8)

to the Marathon situation.

 According to subsection

 (b) (8) up to

25

 of the volume of flow of the receiving stream is available

for mixing (dilution) j~the ratio of the stream flow to the

effluent discharge is greater than 3:1.

 Subsection

 (b) (8)

further provides that no mixing

 (dilution) is allowed if the 7Q10

is zero.

For the Marathon discharge the ratio of stream flow to

effluent discharge is less than 3:1.

 The “up-to-25”

 provision

of subsection

 (b) (8) accordingly does not apply.

—7—

The unnamed tributary does not have a 7Q10 of zero.

Accordingly, the “no mixing” provision of subsection

 (b) (8) also

does not apply.

In this circumstance, the parties seen to have concluded

that it is correct to interpolate between the 25-mixing

 and no-

mixing conditions cited at subsection (b)(8).

 In this vein,

Marathon

produces

graphs

illustrating

the

interpolation

procedure.

 (Marathon brief at p.

8,

 10.)

 The interpolation

procedure, however, is without justification, either

mathematically or legally.

Mathematically there is no justification for a linear

 interpolation, particularly so when the ordinate is not linear;

there is also no justification for the assumption that the limit

for a ratio of

0:.

 is a 100

 dilution allowance.

Legally there

 is no basis for the interpolation.

 Subsection

(b) (8)

 on its face addresses just two circumstances: what is

allowed when dilution is greater than 3:1, and what is allowed

when the 1Q10 is zero.

 Nothing is said in subsection

 (b) (8)

about any other circumstances, including the circumstance of the

Marathon discharge.

 Subsection

 (b) (8)

 is simply mute on the

circumstance of the Marathon discharge.

Subsection

 (b) (8) therefore does not enter into the

determination of a mixing/dilution value in the instant case.

Other provisions in subsection

 (b) may.

 For example, not all of

the flow in a receiving stream may be used for dilution lest the

provision for a zone of passage at subsection

 (b) (6) be violated.

Similarly,

 it is possible that the amount of allowed dilution

might be defined on a parameter by parameter basis, including the

possibility of no allowed mixing for some parameters pursuant to

subsection

(b) (9).

A second point of some issue is the matter of a mixing zone

applicable to the Marathon discharge.

 Marathon requests, for

example, that the Board remand this matter to the Agency with

instruction that the Agency “calculate a mixing zone for the

 stream”.

 (Marathon brief at p.17.)

It would appear that both parties miscomprehend the nature

of a mixing zone and how a mixing zone is different from allowed

mixing.

 The nature of a mixing zone is set forth at 35 Ill.

Adm.

Code 302 .102 (d)

—

(i).

 Pursuant thereto, a mixing zone is a

physical volume with dimensions of length, width, and depth, not

percentage of flow (compare Marathon Brief at p. 7—11 and Agency

brief at p. 9-18).

 Moreover,

 a mixing zone is a condition in an

NPDES permit that derives because the permit applicant provides

proof that allows the Agency to determine that the proposed

mixing zone conforms with federal and State law.

 (Section

302.102(d) and

 (f).)

 These and other facets of mixing zones have

been discussed in some detail by the Board in the opinion that

—8—

accompanied adoption of the current Section 302.102.

 (See In re:

Amendments to Title 35, Subtitle C (Toxics Control), R88-21(A),

107 PCB 283-9, January 25,

 1990.).

 For additional discussion of

the distinction between allowed mixing and mixing zones the

parties are directed to the Illinois Supreme Court’s opinion in

Granite

City

Division of National Steel Company et al.

 v. The

Illinois Pollution Control Board,

 613 N.E.2d 719,

 155 Ill.

 2d 149

(1993).

There is no indication that Marathon has presented the

Agency with the proof necessary for the Agency to determine a

mixing zone.

 To remand with instructions that the Agency

determine a mixing zone would constitute shifting a burden of

proof to the Agency.

 This the Board will not do, and accordingly

the request to remand for a mixing zone determination is denied.

Moreover, should Marathon wish to receive a mixing zone

determination,

 it will have to follow the appropriate application

procedures as part of a new permit application.

 The Board will

not allow the instant application or its adjudication to be

burdened with the new issue of a mixing zone determination.

Lastly, Marathon contests the Agency’s use of the design

average flow in determining Marathon’s dilution ratio.

 Use of

the design average flow in circumstances like this is in line

with standard engineering practice (e.g.,

 see Wastewater

Treatment Plant Design, Water Pollution Control Federation Manual

of Practice No.

 8 and American Society of Civil Engineers Manual

on Engineering Practice No.

36,

p.

 6); Marathon presents nothing

that convinces the Board that the standard practice is

inappropriately applied here.

Toxicity Testing/Evaluation

The September 30,

 1992 permit contains at conditions 13,

14,

and

 15. provisions relating to toxicity testing, including at

condition 15 a provision that requires Marathon to conduct a

Toxicity Reduction Evaluation (TRE).

 Marathon now pleads that

the “Board remand this matter to the Agency with instructions to

impose toxicity testing and a TRE in a manner consistent with

U.S. EPA guidance”.

 (Marathon brief at p.

 17.)

However, Marathon fails to point the Board to any USEPA

guidance that the toxicity provisions of the September 20,

1992

permit are allegedly inconsistent with,

 either generally or

specifically.

 Moreover, Marathon also does not present argument

that USEPA guidance even controls the content of the permit

conditions.

The Board reminds Marathon that in review of contested

permit conditions it is the burden of the petitioner to prove

that there would be no violations of the Act or Board regulations

if the permit were to issue with different conditions.

 (e.g.,

—9—

Browning-Ferris Industries of Illinois.

 Inc.

 v. Pollution Control

Board (2nd District 1989),

 179 Ill.

 App.

 3d 598,

 534 N.E.2d 616.)

Marathon has not met this burden,

 and the Board must thereby deny

remand of the permit as regards consistency of toxicity testing

and evaluation.

Although this denial disposes of the sole toxicity issue

before the Board, for the purposes of assuring that there be no

future confusion on the matter,

 the Board again believes that

some further discussion is warranted.

Underlying much of the issue of toxicity testing/evaluation

appears to be the matter of how the new

WWTP

should be factored

into the permit.

 Even though it is never so explicitly put,

Marathon appears to view the toxicity provisions of the September

30,

 1992 permit as onerous and unnecessary given the presence of

the new WWTP.

 (See Tr. at 21—22; Marathon brief at p. 13-14).

The Board finds nothing in the record that demonstrates that

the presence of the new

WWTP

warrants a change in the provisions

of the September 20,

 1992 permit.

 It would certainly be honed

that the new

WWTP

has

 caused Marathon’s effluent to be improved.

However, this does not rise to the level of the necessary proof.

Finally, the Board notes that it is uncontested that the

waters of the unnamed tributary have exhibited a degraded aquatic

community associated with toxicity of its waters.

 This fact is

not only documented within the instant record

 (e.g., Rec. Exhs.

1

and 20), but has been presented in several prior actions brought

by Marathon before this Board (Marathon v.

 IEPA, PCB 85-83,

67

PCB 513, January 23,

 1986; In the Matter of: Marathon Petroleum

Company Site—Specific, R87—2,

 103 PCB 133, September 13,

 1989;

Marathon v.

 IEPA, PCB 91-173, October 7, 1993;

 In re: Marathon

Site-Specific, R9l-23, October

 7, 1993).

 The Board shares the

deep concerns of the Agency regarding the toxicity in the unnamed

tributary.

 This toxicity does need to be characterized and

eliminated.

 On this basis the Board affirms that the

requirements for both toxicity testing and a TRE are conditions

necessary to assure compliance with the Act and the Board’s

regulations.

Public Hearing and Agency Rules Governing NPDES Permits

Marathon alleges that the Agency is in violation of the Act

and Board regulations because it failed to hold a public hearing

in this matter and because the Agency has not promulgated rules

governing the issuance of NPDES permits.

 Marathon asks that the

Board direct the Agency to afford Marathon a hearing on its NPDES

permit, and to further direct the Agency to come into compliance

with the Act and promulgate procedures for the issuance of NPDES

permits.

—10—

The

Board

finds

that

these

allegations

are

improper

enforcement in a permit appeal proceeding.

 In a permit appeal

proceeding the Board may not entertain challenges to the Agency’s

performance of its duties in the granting of permits.

 (See,

Landfill.

Inc.,

Pollution

Control

Board

(1978),

387

N.E.

258).

Assuming arguendo that the matter of the hearing was

properly before the Board in this permit appeal, the Board still

could not find favor with Marathon’s request for the Agency to

now be ordered to hold a hearing.

Whether an Agency hearing is to be held in an NPDES permit

review is discretionary with the Agency,

 as has been declared by

the

appellate

court:

apparent

from

the

language

this

Rulet5~that

the

decisions

whether

hold

public

hearing

made

the

Agency,

based

upon

its

determination

as to the existence of a significant degree of public

interest in the permit or group of permits.

 It is a

discretionary decision to be made by the Agency.

(Borg—Warner

Corp.

 V. Mauzy,

 100 Ill. App. 3d 862,

427

N.E.2d 415, 56 Ill. Dec. 335

 (3rd Dist.

 1981).)

Marathon presents no argument that would allow this Board to

conclude that the Agency abused this discretion or otherwise

failed to comport with the requirements pertaining to NPDES

 hearings.

This opinion constitutes the Board’s findings of fact and

conclusions of law in this matter.

~ The “Rule” here referred to reads:

The Agency shall hold a public hearing on the issuance

or denial of an NPDES Permit or group of permits

whenever the Agency determines that there exists a

significant degree of public interest in the proposed

permit or group of permits

 (instances of doubt shall be

resolved in favor of holding the hearing), to warrant

the holding of such hearing.

At the time this rule was addressed by the Court it was Rule

909(a)

 of the Board’s Water Permits rules,

 Chapter 3, Part IX.

Upon codification Rule 909(a) was moved to 35 Ill. Adm. Code

309.115(a) (1), where it now resides.

—11—

ORDER

This matter is hereby remanded to the Illinois Environmental

Protection Agency for reissuance of NPDES permit No.

 IL0004073

consistent with the Board’s findings of fact and conclusions of

law in this matter.

IT IS SO ORDERED.

Section 41 of the Environmental Protection Act (415 ILCS

5/41

 (1992)) provides for the appeal of final Board orders within

35 days of the date of service of this order.

 The Rules of the

Supreme Court of Illinois establish filing requirements.

 (See

also 35 Ill.Adm.Code 101.246 “Motions for Reconsideration”.)

I, Dorothy M. Gunn,

 Clerk of the Illinois Pollution Control

 Board, hereby certify that the above o inion and order was

adopted on the

~3/~4

 day of

____________________,

 1994, by

a vote of

_______________

Dorothy M. ç~nn,Clerk

Illinois PQ~1utionControl Board