ILLINOIS POLLUTION CONTROL BOARD

July 31, 1986

BLOOMINGTON AND NORMAL SANITARY

DISTRICT,

Petitioner,

)

PCB 86—116

ILLINOIS ENVIRONMENTAL

PROTECTION AGENCY,       

)

Respondent.

OPINION AND ORDER OF THE BOARD (by J. D. Dumelle):

This provisional variance request comes before the Board

upon a July 31, 1986 Recommendation of the Illinois Environmental

Protection Agency (Agency). The Agency recommends that a 45—day

provisional variance be granted to the Bloomington and Normal

Sanitary District from 35 Ill. Adm. Code 304.120(c) and 35 Ill.

Mm. Code 304.141(a) to allow the Petitioner to exceed its NPDES

Permit effluent biochemical oxygen demand (BOD) and total

suspended solids (TSS) limits during the time period that the

tertiary filters are bypassed while the filters are out of

service for structural inspection and repair. The Bloomington

and Normal Sanitary District was previously granted a provisional

variance in PCB 85—34 on March 22, 1985 to allow the rebuilding

and replacement of the tertiary filters’ media and to allow the

construction of some piping changes around the filters. (See:

Opinion and Order of March 22, 1985 in PCB 85—34, Bloomington—

Normal Sanitary District v. IEPA). However, the Petitioner has

not yet completely rebuilt and replaced the media of its tertiary

filters because of unanticipated wastewater treatment plant

operating constraints. (Rec. 1).

The Bloomington and Normal Sanitary District, which serves

approximately 85,000 residents in a 25 square mile area, owns and

operates three wastewater treatment facilities. Preliminary,

primary, and secondary treatment are provided by each of these

three wastewater facilities before their secondary effluents are

combined for tertiary treatment and disinfection. (Rec. 1).

Additionally, each facility has the capacity to disinfect its

secondary effluent individually if necessary. These three

facilities have a total design average flow of 16.0 million

gallons per day (rngd). Effluent from the Petitioner’s wastewater

treatment facilities is discharged to Sugar Creek, tributary to

Salt Creek, the Sanganion River, and the Illinois River.

(Pet.

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The Petitioner’s NPDES Permit #1L0027731 provides that its

wastewater treatment facilities must meet tertiary effluent con-

centration limits of 10 milligrams per liter (mg/l) biochemical

oxygen demand and 12 mg/l total suspended solids as a monthly

average and 15 mg/l BOD and 18 mg/i TSS as a 7—day maximum

average plus associated loadings limits. In its letter to the

Agency dated July 24, 1986, the Petitioner submitted the fol-

lowing table which summarizes the relevant monitoring and past

secondary effluent data pertaining to actual flow, BOD, and total

suspended solids levels:

TABL.E I

BL~CK~IlNGTONAND NORMAL

SANITARY

DIS~IR1CT

nonth period

1984

1985

July ‘85 

—

June

‘86

Aug. Sept. 

Oct. Aug. Sept. Oct.

*plaflt

1

Flow(ngd)     

5.4  3.9  

6.5  8.8 6.1  7.6     

8.1

BZID(mg/l)

31.8 27.4 23.8 17.3 26.6 17.0    

23.4

SS(mg/1)

28.0 22.7 21.9 20.2 21.0 24.6    

28.0

Plant 2

Flow(mgd)     

0.5  1.7  

2.0  1.6 1.9  1.7     

2.1

&~D(mg/1)

15.8 8.8  

7.4  4.9 8.3  

9.3

13.0

SS(mg/1)

26.9 11.6  

8.5  5.0 9.3 21.1     

15.6

Plant

Flow(mgd)     

5.9  7.0  

6.3  5.9 6.0  7.2     

7.4

9~D(mg/l)

8.4

9.6

7.6

5.1 8.1  

6.1

6.6

SS(~r~g/1)

9.8 13.7 10.7  6.4 12.3 16.0    

11.2

**c~j~Ø5j~~

Sample

Flow(mgd)    

11.8 12.6 14.8 16.3 14.0 16.5     

17.6

~D(mg/1)

19.4 15.0 14.7 11.7 16.2 11.4    

15.1

SS(uvg/l)

18.9 16.0 15.3 13.7 15.7 20.5    

19.5

***Fjnal Effluent

Flow(mgd)    

11.9 12.5  14.8 16.2 14.0 16.6     

17.6

a~D(mg/I)  

11.0 10.0 10.0 8.0 10.0  6.0     

10.2

~DT(mg/l)   

N/A N/A  N/A 5.4 7.9  5.3     

7.6

SS(~g/1)

3.0  3.0  

4.0 4.0 5.0  6.0     

8.8

tPlant 1,2,3 secondary effluents

**Co(tposjte sample 

based

upon weighted averaging for 3 plant 

secondary

effluents.

***Final effluent is with tertiary filtration

BODT

~)D carbonaceous 

nitrogenous demand

BOD carbonaceous demand

7 1-452

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The Petitioner has requested effluent limitations of 25 mg/i

for both BOD and TSS as 30 day averages during the requested

45—day provisional variance period. Those limits will be

determined from a composite sample based upon the weighted

averaging for the three secondary plant effluents with no

tertiary filter treatment. From the past secondary effluent data

delineated in Table I, the Agency has concluded that the

“Petitioner should generally be able to meet the requested

effluent limits without the tertiary filters”. (Rec. 2).

In reference to the rationale for its provisional variance

request, the Petitioner stated in its letter to the Agency dated

July 24, 1986 that:

The tertiary filter has recently exhibited

structural problems with the media support floors. On a

preliminary basis, these problems have been identified

as loosening and failure of the media support anchor

system. The floor in one of the cells has “blown up”

during backwash, with pull—out of the anchors and

cracking of some of the media support plates. Other

cells also exhibit substantial movement of floor during

backwash. The District intends to implement a compre-

hensive structural investigation to determine the cause

of this failure and to develop a program for

correction. In order for the District to implement such

an investigation and take corrective action, it will

have to removal all of the media to inspect the media

support anchoring system in all 16 cells.

Additionally, the tertiary filter has experienced media

loss over the past several years. The District was in

the process of addressing the media loss problem when

the structural failure problem came into existence. In

order for the District to rebuild the media and bring

the filter up to optimum operational capability, the

structural problem has to be corrected first. Recent

evidence indicates that some media loss may be occurring

due to floor uplift, in addition to media loss over the

weirs. Compliance with provisions of the Act will

certainly impose an arbitrary and unreasonable hardship

since the District cannot provide tertiary level treat-

ment if the filter is out of service. The District is

able to provide good quality secondary effluent without

filtration. Additionally, the filter does not have the

‘structural integrity and physical media capability to

handle high flows in its present condition. Further-

more, the other media support floors may buckle, if kept

in operation, leaving the District with a filter in a

more extensive state of repair.” (Pet. 1—2).

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As indicated in the aforementioned statements of the

petitioner, the Bloomington and Normal Sanitary District does not

intend to replace and rebuild the media until the serious problem

relating to the media support floors has been investigated and

appropriately repaired. In reference to the propriety of this

method of operation, the Respondent has indicated that “the

Agency agrees with Petitioner that it would be unwise to replace

and rebuild the media prior to investigating and correcting the

media support floor problem.” (Rec. 2). To rectify its media

support floor problems, the Petitioner intends to remove the

media from all sixteen of the tertiary filter cells so that the

media support floor in each cell can be carefully inspected. The

Bloomington and Normal Sanitary District has entered into a con-

tract with, and already retained, the structural consulting firm

of Wyss, Janney and Elstner to analyze and evaluate the

structural capacity of the tertiary filter through detailed

physical inspection of the media support floor and the media

support anchoring system; by thorough physical inspection and

review of all pertinent design criteria; arid by performing the

requisite testing before replacement of the media and placement

of the filter in operation. The structural engineering

consulting firm has been retained to appropriately evaluate the

situation and to present its conclusions and to recommend

engineering solutions to the Petitioner, since the sanitary

district is, at the present time, unsure of the solution to its

problems. (Rec. 2). The Petitioner has estimated that it will

cost approximately $250,000.00 to properly effectuate its filter

restoration. (Pet. 3).

The Petitioner has asserted that it has previously

demonstrated good faith by diligently working to keep the

tertiary filter out of service a minimum time during 1985. The

sanitary district has noted that it enhanced effluent quality by

re—routing the drain—down water piping and removing it from the

filter—bypass line and by making chlorine piping changes at the

filter in 1985 to provide better cleaning capability, while

keeping the filter out of service only three days during these

piping operations. (Pet. 4—5).

In the present situation, the Petitioner has indicated that

“the actual time needed for restoration of the filter can only be

determined when the extent of the structural problem is known arid

the method of correction is defined.” (Pet. 4).

The Petitioner believes that, at the present time, there is

no practical alternative to removing the tertiary filters from

service in order to properly evaluate and correct the media

support floor problem. The Petitioner has stated that:

There are no other alternatives to consider if

the filter is to be put back into full operational

71-454

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capability. The structural integrity of the filter has

to be restored. As the media has to be removed to

inspect the floor and anchor system, the opportunity to

restore the media to the proper depth can also be

achieved at this time. If the District is not allowed

to take the filter out of service, it will only be a

short matter of time before the filter floor collapses

and the District will no longer be able to achieve

compliance with its NPDES permit limits.” (Pet. 4).

The Agency has also indicated that, in view of the need to

remove the tertiary filters from service in order to resolve the

media support floor problem, it “agrees with Petitioner’s assess-

ment of the alternatives”. (Rec. 2)

The sanitary district has stressed that it anticipates no

adverse environmental impact on the receiving stream during the

time period of the requested provisional variance. In its

assessment of the environmental impact, the Petitioner notes

that:

The receiving stream has sufficient flow

available at this time of year (August—October) to

adequately handle effluent of good secondary quality.

Table I contains monitoring information on the

District’s facilities. Table II reflects the downstream

fish monitoring results obtain in 1985. Tables III and

IV reflect the 5 year period from May 1, 1980 to

April 30, 1985 and indicate percent of total flow given

complete treatment (tertiary). The District is able to

disinfect the three secondary effluents. The District

maintains a 14 station water quality monitoring network

throughout its 25 square mile service area, including

5 stations up to four miles downstream of the treatment

plant. Any changes in water quality from 1-4 miles

downstream can be detected. Furthermore, the District

maintains a 20 station biological monitoring network.

The District will be able to document any 

changes in

fish number or fish species for a distance of up to

20 miles downstream. It should be noted that under

average flow conditions and within 5 days, the effluent

will have traveled 113 miles distance and will have

reached a point 18 miles in the Illinois River where the

average flow is 17,600 cfs.” (Pet. 3—4).

The Agency agrees with the Petitioner’s environmental

assessment and believes that “the expected environmental impact

will be minimal because disinfected secondary effluent will be

discharged”. (Rec. 2—3). Additionally, the Agency thinks that

any adverse environmental impact will be readily detected, and

treatment operations modified accordingly by the Petitioner as

capabilities allow, because the sanitary district “has

71-455

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established its own water quality and biological monitoring

stations downstream of its discharge”. (Rec. 3).

The Petitioner has claimed that denial of its requested

provisional variance would cause an arbitrary or unreasonable

hardship “since the District cannot provide tertiary level treat-

ment if the filter is out of service” and it would be unfair and

inappropriate to require the Petitioner to meet tertiary effluent

limits while being physically able to provide only secondary

treatment. The Agency agrees with the Petitioner’s contention in

regard to such hardship and has indicated that denial of the

requested relief would place an arbitrary or unreasonable

hardship on the sanitary district because the Petitioner:

(1) “wants to evaluate and correct the problem as quickly as

possible so the tertiary filters can be returned to service”;

(2) “has, and is willing to spend, the money necessary to

evaluate and correct the tertiary filter problems”, and (3) “has

demonstrated via past data that it has the capability to produce

good secondary effluent while the tertiary filters are out of

service”. (Rec. 2).

Accordingly, the Agency has concluded that compliance on a

short—term basis with the provisions of 35 Ill. Adm.

Code 304.120(c) and 304.141(a) would impose an arbitrary or

unreasonable hardship upon the Petitioner. The Agency has stated

that there are no Federal regulations which would preclude the

granting of the requested relief and there are no downstream

public water supplies which would be adversely affected by the

granting of the provisional variance. Therefore, the Agency

recommends that the Board grant the Bloomington and Normal

Sanitary District a provisional variance from Sections 304 .120(c)

and 304.141(a) for a period of 45 days, subject to certain

conditions.

Pursuant to Section 35(b) of the Illinois Environmental

Protection Act, the Board hereby grants the provisional variance

as recommended.

This Opinion constitutes the Board’s findings of fact and

conclusions of law in this matter.

ORD ER

The Petitioner, the Bloomington and Normal Sanitary

District, is hereby granted a provisional variance from 35 Iii.

Adin. Code 304.120(c) and 35 Ill. Adm. Code 304.141(a), subject to

the following conditions:

1. This provisional variance shall begin when the

tertiary filters are first removed from service and

shall continue for 45 days, or until the tertiary

filters are returned to service, whichever occurs

first.

7 1-456

—7—

2.  Effluent shall be limited to 25 mg/l weighted

average of the three secondary effluents for both

BOD and TSS as monthly averages. Effluent shall be

sampled by the Petitioner according to NPDES Permit

~IL002773l as to frequency and sample type.

Analysis results shall be submitted to the Agency

on the monthly discharge monitoring report as

30 day averages.

3.  The Petitioner shall notify Pat Lindsey of the

Agency’s Compliance Assurance Section via telephone

at 217/782—9720 when the tertiary filters are taken

out of service and when they are returned to

service. Written confirmation of each telephone

notification shall be submitted within 5 days to

the Agency at the address given below:

Illinois Environmental Protection Agency

Division of Water Pollution Control

Compliance Assurance Section

2200 Churchill Road

Springfield, Illinois 62706

Attention: Pat Lindsey

4.  The Petitioner shall keep the Agency apprised of

the tertiary filter situation, especially con-

cerning necessary corrective measures and estimated

time frames to implement and complete them.

5.  The replacement and rebuilding of the tertiary

filter media shall be included as part of the final

scheme for returning the tertiary filters to

service.

6.  The Petitioner shall operate the remainder of the

three treatment facilities so as to produce the

best effluent possible.

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

the Petitioner shall execute a Certification of

Acceptance and Agreement which shall be sent to

Mr. James Frost of the Agency at the following

address:

Mr. James Frost

Illinois Environmental Protection Agency

Division of Water Pollution Control

2200 Churchill Road

Springfield, Illinois 62706

71-457

—8—

This certification shall have the following form:

I, (We), ________________________________, having read the

Order of the Illinois Pollution Control Board in PCB 86-116 dated

July 31, 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

IT IS SO ORDERED.

I, Dorothy M. Gunn, Clerk of the Illinois Pollution Control

Board, hereby certj,fy that the above Opi~ion,.and Order was

adopted on the ~    

day of 

_____________________,

1986 by a

vote of 

_________________.

‘2

~7

orothy M. Gurn, Clerk’

Illinois Pollution Control Board

71-458