ILLINOIS POLLUTION CONTROL BOARD
January 23, 1986
GREATER PEORIA SANITARY DISTRICT, )
)
Petitioner,
)
)
v.
)
PCB 86-14
)
)
ILLINOIS ENVIRONMENTAL
)
PROTECTION AGENCY,
)
)
Respondent.
)
OPINION AND ORDER OF THE BOARD (by
~. J.
Nega):
This provisional variance request comes before the Board
upon a January 23, 1986 Recommendation* of the Illinois
Environmental Protection Agency (Agency). The Agency recommends
that a 45-day provisional variance extension be granted to the
Greater Peoria Sanitary District (GPSD) from 35 Ill. Adm. Code
304.120 (deoxygenating wastes), 35 Ill. Adm. Code 304.121
(bacteria), and
35
Ill. Adm. Code 304.122 (nitrogen) while
portions of GPSD’s secondary treatment facilities
are temporarily
out of service during the time period that necessary repairs are
being made.
The Board previously granted the Petitioner
a 45-day
provisional
variance in PCB 85-193.
(See:
Opinion and Order of
November 21, 1985 in PCB 85-193, Greater Peoria Sanitary District
v. IEPA.) However, the Petitioner has found that the requisite
repairs will take more time than originally anticipated and has,
therefore, requested the instant provisional variance extension.
The Greater Peoria Sanitary District owns and operates
wastewater treatment facilities serving the City of Peoria, some
outlying communities, and several industries. The Petitioner’s
facilities
include screening, grit removal, primary and secondary
clarification, activated sludge, nitrification utilizing rotating
biological contactors (RBC’s), tertiary ponds, and chlorination
equipment.
Prior to its disposal, sludge
is first thickened,
treated anaerobically, and then
dried. The Petitioner’s
treatment plant has a design average flow of 37 million gallons
per day (MGD) and
discharges directly into the
Illinois River
pursuant to the
appropriate NPDES Permit authorization. (1st
Rec. 1; 2nd Rec. 1-2).
*The Agency has incorporated
by reference
its November 21,
1985 Recommendation in PCB 85-193 into its January 23, 1986
Recommendation in PCB
86-14. Accordingly, the November 21, 1985
Recommendation in PCB 85-193 will be cited as
“1st Rec.”, while
the January 23, 1986 Recommendation in PCB 86-14 will be
cited as
“2nd Rec.”.
67-553
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During the middle of October, 1985, the Petitioner
discovered that, due to groundwater related erosion problems,
portions of its secondary treatment system’s aeration tanks,
aeration gallery, and secondary clarifiers had become seriously
undermined. Bottoms of several aeration tanks, a part of the
aeration gallery floor, and at least one corner of the bottom of
one secondary clarifier had dropped up to two inches into the
voids below. As a result of the leaks that had started
developing in the walls and floors of its activated sludge tanks,
mixed liquor was flowing in a stream up to 4 inches deep into the
aeration gallery. The aeration gallery, which houses equipment
for the aeration tanks, is a tunnel-like structure which is below
grade and next to the aeration tanks.
To stop these leaks and to provide access for investigatory
work and repairs as well as to minimize additional undermining of
the tanks, the Petitioner removed nine of its twelve aeration
tanks and three of its five secondary clarifiers from service in
mid-October. Of the remaining three aeration tanks, two are
being utilized as contact tanks and the third is being utilized
as a reaeration tank. The Petitioner’s employees have begun to
dewater various aeration tanks in order to find the leaks. The
apparent cause of the leaks is the development of “voids” (i.e.,
areas of water and/or mud) beneath aeration tanks. (1st Rec. 1;
2nd Rec. 2).
The Petitioner is currently required by its NPDES Permit
#1L0O21288 to meet effluent limitations of 20 mg/i of biochemical
oxygen demand (BOD) on a 30 day average with a 40 mg/l BOD limit
as a weekly average, and to meet effluent limitations of 25 mg/l
of total suspended solids (TSS) on a 30 day average with a 45
mg/i TSS limit as a weekly average. This NPDES Permit also
delineates a 2.5 mg/l effluent standard for ammonia nitrogen as N
during the months of April through October, and a 4.0 mg/l
effluent standard for ammonia nitrogen as N during the months of
November through March. (1st Rec. 2).
According to discharge monitoring reports submitted to the
Agency by the Petitioner, the following results were indicated:
Monthly Average
NH3-N
Flow
BOD
TSS
Month
(MCD)
(mg/i)
(mg/l)
(mg/i)
9/85
22.29
4
4
1.9
8/85
22.65
4
4
1.9
7/85
22.31
5
7
1.2
6/85
23.24
7
ii
2.5
5/85
23.21
7
10
3.1
4/85
29.06
5
10
2.5
67-554
—3-
Monthly Average
NH3-N
Flow
BOD
TSS
Month
(MCD)
(mg/i)
(mg/i)
(mg/i)
3/85
34.39
7
20
1.8
2/85
29.12
5
8
2.6
1/85
25.57
7
8
2.1
12/84
28.18
4
7
1.4
11/84
26.14
7
7
3.0
10/84
22.99
12
7
3.8
Average
25.76
6.2
8.7
2.3
(1st Rec. 2).
However, due to the groundwater-related erosion problems and
the tank leaks, the Petitioner has indicated to the Agency that
its effluent quality has already significantly deteriorated. For
example, the average BOD for all of October 1985 was 15 mg/i,
while the average BOD for the last half of October, 1985, when
flows had begun to be diverted, was 22 mg/i. (1st Rec. 2). The
Petitioner has reported that TSS levels have experienced similar
deterioration due to the problems at the facility. Moreover, it
is possible that fecal coliform levels might rise due to
increased chlorine demand and CPSD anticipates
that the effluent
quality will deteriorate even further in the near future. (1st
Rec. 2).
Since CPSD’s rotating biological contactor nitrification
system is currently receiving much of the plant’s primary
effluent, a very real risk of overloading the RBC shafts
exists. The Petitioner is now providing effluent treatment by
use of its three in-service aeration tanks and by diverting flows
to the RBC’s, and then to the polishing pond and chlorination.
In reference of this diversion of flows to the RBC’s, the Agency
has stated that:
“...
the RBC’s were not designed to treat the
strength of wastes that are now being applied to
them. Based upon the Agency’s past experience with
RBC’s, structural failure of the RBC’s could result
due to the increased biomass growth on the units
thus causing the shafts to break due to the extra
weight of the biomass. Petitioner’s personnel are
routinely monitoring the performance of the RBC’s
and will be able to provide minimum treatment
consisting of primary clarification, tertiary
clarification, the polishing lagoon, and
chlorination.” (1st Rec. 2).
The Agency has noted that CPSD has already begun corrective
action in that core drillings which are about two inches in
diameter have been completed which led to the determination that
some of the voids beneath the aeration gallery floor are as deep
67-555
—4—
as 89 inches. The Petitioner’s core drillings were taken about
every five to ten feet through the aeration gallery floor and
core samples which are about five inches in diameter have been
analyzed.
In reference to the plan of corrective action and the
necessary repair and maintenance work, the Agency has indicated
that:
“The core drillings have been completed
and Petitioner has determined a course of
corrective action. Another 150 holes will be
drilled in the floor of the gallery and the
aeration tanks. Also, the drainage system
under the tanks will be plugged. Once these
actions are completed, Petitioner will begin
pumping pressure grouting.
...At the last meeting of Petitioner’s
Board of Trustees, a proposal was made by
Petitioner’s technical staff to begin these
repairs under change order, thus expediting
the commencement of repairs. The Board agreed
and the additional borings should have already
begun. Pumping of the pressure grout should
begin in two (2) weeks. Petitioner believes
that repairs should be completed by
February 19, 1986. Petitioner does not know
how much grout will have to be pumped in order
to repair the tanks.
...Petitioner has been using its
remaining treatment units as required by the
previous order. The RBC’s are currently
loaded at about 75 of their design loading
and if biomass continues to grow as expected,
these units may have to be partially by-passed
to prevent their failure.
...Petitioner reports that it is meeting
the terms of the variance. However, it is
concerned that because of the reduced
treatment capability and thus increased
chlorine demand that fecal coliform levels in
its effluent are high while chlorine residual
levels are at or near zero. The chlorination
equipment is apparently operating at its
maximum capacity. Petitioner has been
continuing its ammonia nitrogen study on the
Illinois River and believes that there has
been no noticeable impact even though the
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—5—
Illinois River is now below normal pool
elevation.”
(2nd Rec. 2-3).
The Agency expects that there will be little adverse
environmental impact upon the Illinois River from CPSD’s
presently degraded discharge,
because the Illinois
River at
Petitioner’s
discharge point provides a dilution ratio of
about
74 to
1 using the Illinois
River’s 7 day, 10 year low flow and
CPSD’s average flow over the past year (1st Rec. 2-3). Moreover,
the Petitioner will also be providing as much treatment as
possible which will serve to reduce the environmental impact
further over the discharging of raw sewage. (1st Rec. 3; 2nd
Rec. 3). The Petitioner’s discharge is approximately 168 miles
upstream from the nearest public water supply intake which is the
City of Alton’s intake on the Mississippi River. (1st Rec. 3;
2nd Rec. 4).
Based on the inability of the Petitioner to provide full
treatment when units had to be taken out of service to retain
what was left of their structural integrity, the Agency has
stated that the “Petitioner’s hardship in this case is readily
apparent.” (1st Rec. 2; 2nd Rec. 3). The Agency has also
indicated that there are no federal regulations that would
preclude the granting of the provisional variance.
The Agency has therefore concluded that compliance with
applicable standards would impose an arbitrary or unreasonable
hardship upon the Greater Peoria Sanitary District. (1st Rec. 2;
2nd Rec. 1). Accordingly, the Agency has recommended that the
Board grant Petitioner a provisional variance extension from 35
Ill. Adm. Code 304.120, 304.121, and 304.122, subject to certain
conditions.
Pursuant to Section 35(b) of the Illinois Environmental
Protection Act, the Board will grant the provisional variance
extension as recommended.
This Opinion constitutes the Board’s findings of fact and
conclusions of law in this matter.
ORDER
The Creater Peoria Sanitary District is hereby granted a 45-
day extension of its prior provisional variance from 35 Ill. Adm.
Code 304.120, 304.121, and 304.122, subject to the following
conditions:
1. The provisional variance shall commence on January 5,
1986 and shall terminate 45 days thereafter.
2. During the term of this provisional variance, the
Petitioner’s effluent shall be limited as follows:
67-557
—6—
Parameter
Monthly Average
BOD
50 mg/l
TSS
50 rng/l
Ammonia nitrogen discharges shall not cause a violation of
water quality standards.
3.
Chlorination shall be provided for all flows discharged
through Outfall OOla and the Petitioner shall make every effort
to comply with the 400/100 ml fecal coliform standard.
4.
The Petitioner
shall provide the maximum degree of
treatment possible by using all treatment units possible.
5. The Petitioner shall immediately notify the Agency’s
Peoria Regional Office by telephone if more units are removed
from service and when the aeration units are returned to
service.
This notification
shall be supplemented by a written
notice within 5 days submitted to:
Illinois
Environmental Protection Agency
Division of Water Pollution Control
Compliance Assurance Section
2200 Churchill Road
Springfield, Illinois 62706
Attention: Mr. Roger Cruse
6. 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
This certification
shall have the following form:
I, (We),
,
having read
the Order of the Illinois Pollution Control Board in PCB 86-14,
dated January 23, 1986, understand and accept the said Order,
realizing that such acceptance renders all terms and conditions
thereto binding and enforceable.
Petitioner
By: Authorized Agent
67-558
—7--
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
_______________
day of
~
,
1986 by a vote
of
_____________.
/
Dorothy M. Gunn, Clerk
Illinois
Pollution Control Board
67-559