ILLINOIS POLLUTION CONTROL BOARD

April 3, 1980

CENTRAL ILLINOIS PUBLIC SERVICE COMPANY,

(ilutsonville Power Station)

Petitioner,

v,

)

PCB 80—16

ENVIRONMENTAL PROTECTION AGENCY,     

)

Respondent.

OPINION AND ORDER OF THE BOARD (by Dr. Satchell):

This matter comes before the Board upon a variance petition

filed January 21, 1980 by Central Illinois Public Service Company

(CIPS). The petition requests for the Hutsonville power station

a variance from the effluent standards for copper (total) 

iron

(total) and iron (dissolved) which are found in Rule 408(a) of

Chapter 3: Water Pollution. On March 3, 1980 the Environmental

Protection Agency (Agency) recommended that the variance be

granted with conditions. The hearing was waived and the Board

has received no public comment.

The Hutsonville power station is a 210 megawatt fossil—

fueled electric generation plant which is situated two miles north

of Hutsonville, Crawford County. On October 23, 1979 the Agency

issued for the facility renewed NPDES Permit IL 0004120. This

authorizes discharges from an ash pond to the Wabash River and

discharge of boiler chemical and air heater cleaning solutions to

the ash pond. The previous permit designated the ash pond dis-

charge to the Wabash River as the point of discharge for these

solutions. The new permit reauires application of the Rule 408(a)

effluent standards at the point of discharge to the ash pond. On

November 21, 1979 CIPS filed a petition for review of these permit

conditions which is pending before the Board (PCB 79-247).

During ordinary operation deposits build up inside boiler

tubes. At Hutsonville these deposits are mostly iron and copper

compounds which derive from corrosion of metal in the system. CIPS

cleans boilers 5 and 6 at Hutsonville about once in three years.

Cleaning is to take place during scheduled outages which for Boiler

S is from February 3 through March 22, 1980 and for Boiler 6 is

from April 27 through June 21, 1980. Delay in cleaning could re-

sult in damage to the boiler. Rescheduling of cleanings is dif-

ficult since CIPS must schedule generator outages with sufficient

lead time to schedule other maintenance and so as to maintain

adequate generating capacity in its system.

—2—

CIPS proposes to clean the boiler tubes by filling each with

about 16,000 gallons (61,000 1) of a solution of ammoniated

ethylenediaminetetraacetic acid (EDTA). This is a chelating agent

which complexes metals rendering them water soluble in conditions

under which they would otherwise be insoluble. After use the

cleaning solution will contain about 700 pounds (320 kg) of iron

and 200 to 300 pounds (90 to 140 kg) of cooper. This will be far

in excess of the concentrations allowed by Rule 408(a). The

boilers will be rinsed three times with water, resulting in another

48,000 gallons (180,000 1) of water per boiler which will contain

less iron and copper but will probably still exceed the concen-

tration limits of Rule 408(a) (Pet. 3). The Agency estimates that

a total of 2000 pounds (900 kg) of iron and 200 pounds (90 kg) of

copper will be removed per boiler (Rec. 2).

This is the first time the EDTA solution has been used at

Hutsonville (Rec. 2). The ash pond provides treatment as well as

dilution for the iron and copper in the effluent since the metals

precipitate as hydroxides under basic conditions present in the

ash pond. However, the Agency believes the EDTA chelated metals

will be much more resistant to precipitation than the metals con-

tained in other cleaning solutions. A detention time of 60 to

120 days may be required. This may be greater than that provided

by the ash oond (Rec. 3).

CIPS retained a consulting engineering firm to investigate

alternative methods of disposal. Three basic engineering alter-

natives were proposed: incineration, chemical treatment and. off—

site disposal. The first two could not be developed in time for

the scheduled 1980 cleanings (Pet. 4). CIPS proposes to haul the

spent EDTA cleaning waste to an Agency approved disposal facility.

The EDTA will be pumped back into the tank trucks which deliver it.

However, it would be impracticable to haul the 48,000 gallons of

rinse water off site for disposal. It is doubtful if enough tank

trucks are available to do this at the present time. Construction

of a holding tank could not be done prior to the cleanings. The

i3oard therefore finds that it would impose an arbitrary and un-

reasonable hardship on CIPS to require immediate pretreatment of

the rinse solutions.

Air heater cleaning involves much l~irgervolumes of water

than boiler cleaning (Pet. 7). Disposal of the contaminated water

poses problems similar to the boiler rinse. The Agency has con-

ceded, for purposes of this variance only, that the ash ponds are

—3—

adequate to precipitate the iron and copper from the air heater

wash solutions. Since very little of this will be discharged to

the Wabash River, the Board will grant a variance for the air

heater cleaning solution wastes also. Since CIPS has not indicated

a different cleaning schedule for air heaters, this variance will

expire upon completion of the boiler cleaning.

This Opinion constitutes the Boardts findings of fact and

conclusions of law in this matter.

ORDER

Central Illinois Public Service Company is granted for its

Hutsonville power plant a variance from the effluent standards

for copper (total), iron (total) and iron (dissolved) of Rule

408(a) of Chapter 3: Water Pollution, subject to the following

conditions:

1. This variance will expire on July 22, 1980.

2. This variance will apply only to boiler cleaning rinse

water and air heater wash discharges into the ash pond.

3.~ Petitioner shall not discharge EDTA boiler chemical

cleaning solution into the ash pond.

4. Petitioner shall conduct a study to determine treatment

capabilities of the ash pond. The study shall include

as a minimum data on pH of the ash pond, the constituents

in the metal cleaning waste rinses, the concentration of

the constituents and the volume of the metal cleaning

waste rinses discharged to the ash pond. A summary of

results shall be sent to the Agency by August 30, 1980.

5. The Agency, pursuant to Rule 914 of Chapter 3: Water

Pollution, shall modify the NPDES Permit IL 0004120

consistent with the conditions set forth in this Order.

6. Within forty—five days of the date of this Order, Peti-

tioner shall execute and forward to the Illinois En-

vironmental Protection Agency, Variance Section, 2200

Churchill Road, Springfield, Illinois 62706, a Certifi-

cate of Acceptance and Agreement to he bound to all

terms and conditions of this variance. This forty-five

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—4—

CERTIFICATION

I, (We), 

______________________,

having read

and fully understanding the Order in PCB 80-16,

hereby accept that Order and agree to be bound by

all of its terms and conditions.

IT IS SO ORDERED.

SIGNED

TITLE

DATE

I, Christan L. Moffett, Clerk of the Illinois Pollution

Control Board, he~~ycertify the above Opinion and Order were

adop~don the ~   

day of 

______________,

1980 by a vote

Christan L. Mof  

Clerk

Illinois Polluti Control Board