ML20005G984

NPDES Noncompliance Notification:On 891227,permit Limit for Zinc Exceeded.Caused by Sampling Inadequacies Rather than Excessive Chemical Discharges.Routine Daily Flushing of Sample Line 001 Performed & Lower Range Control Used

ML20005G984
Person / Time
Site:	Limerick
Issue date:	01/15/1990
From:	Mccormick M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Bauer R PENNSYLVANIA, COMMONWEALTH OF
References
NUDOCS 9001240003
Download: ML20005G984 (5)

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PHILADELPHIA ELECTRIC COMPANY ,

i 2301 M ARKET STREET  ;

P.O. BOX 8699 PHILADELPHI A, PA,19101 1215f e4140oo January 15, 1990 i b Hr. Robert Bauer, Jr.

Department of Environmental Resources Bureau of Water Quality Management 1875 New Hope Street Norristown, PA 19401 Subiect: Follow-up to Noncompliance Letter  !

Limerick Generating Station l NPDES Permit No. PA-0051926

Reference:

NPDES Noncompliance Letter dated 12/21/89

Dear Hr. Bauer:

This letter is a follow-up to the incidents docukented in the December 21, 1989 noncompliance letter and documentation of'an additional noncompliance of our permit limit for zine as per your request. The referenced letter has been attached for your convenience.

One of the weekly samples for total cine that was collected in December was above the permit limit of 1.0 mg/1. The. result of the sample taken on 12/27/89 was 1.1 mg/1. Station personnel were notified of this noncompliance on 1/2/90. Immediate notification to your l

office at the DER was performed on the morning of 1/2/90.

This noncompliance was determined to be due to the same circumstances that caused the previously reported incidents that occurred in November.

We have concluded preliminary investigations into our sampling method for total zinc, and determined that sampling ]

inadequacies, rather than excessive chemical discharges, j were the cause of the reported results.

l The tendency for soluble zine to adsorb onto suspended  !

solids is a recognized occurrence in cooling water treatment. Between sampling events, the 001 discharge sample line experiences extremely low flow conditions, creating the potential for solids to accumulate. It was suspected that insufficient flushing of our 001 sample line prior to zine sampling was resulting in excessive amounts of solids entering the sample, thus causing a positive error. A comparison of zinc levels in 001 samples during various stages of the-flushing process was performed on 1/3/90.

This comparison revealed that samples obtained from the 001 sample line during the early stages of the flush contained as much as 0.9 ppm more zine than the samples obtained from the cooling tower basins, which are the sole source of zinc. 0pk 9001240003 900115 AN PDR ADOCK 05000352 V S PDC

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comparison, it was confirmed that our colorimetric test ,

continues to be a conservative control method. Results for i the cooling tower basins, via this method, were at least 0.1 ppa higher than those determined by atomic absorption.

These findings reaffirm our original contention that the )

actual total zine discharges were likely to be within permit  ;

limitations. l I

Corrective Actions ,

Immediate corrective actions are to perform routine i daily flushing of our 001 sample line and the use of a lower ,

. control range for total zine during daily cooling tower l monitoring. In addition, we are continuiny to modify the i sampling technique to better assure representative samples.

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Plant Manager  !

' Attachment A 1

cci U.S. Nuclear Regulatory Commission w/ attach.  !

Document Control Desk l Washington, D.C. 20555 1

Administrator Region I w/ attach.

U.S. Nuclear Regulatory Commission .

i l 475 Allendale Road l King of Prussia, PA 19406 Station Resident NRC Inspector w/ attach.

Tom Kenny, H.C.# NRC Program Management Section (3WH52) w/ attach.

Permits Enforcement Branch I' Water Management Division Environmental Protection Agency Water Permits Section Region III 841 Chestnut Building Philadelphia, PA 19107 i .

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PHILADELPHIA ELECTRIC COMPANY 2301 M ARKET STREET P.O. BOX 8699 PHILADELPHI A. PA.19101 (215) Sol-dooo December 21,1989 Mr.~ Robert.Bauer, Jr.

Department of Environmental Resources Bureau of Water.Quelity Management.

1875 New Hope. Street.

Norristown, PA 19401

SUBJECT:

Noncompliance with-NPDES permit.

' Limerick Generating Station NPDES Permit No. PA-0051926

Dear.Mr. Bauer:

DESCRIPTION OF NONCOMPLIANCE Discharge Point 001 was sampled once per week for Total Zine'during November. Two of the five samples taken were above the permit limit of 1.0 mg/1. The results of samples

.taken on 11/1/89 and 11/17/89 were 1.1 and 1.5 mg/l respectively. Station personnel were notified of this noncompliance on 12/19/89. Immediate notification to DER was' attempted-and limited information was left with the

. answering service. A follow up call was made to your office the morning of 12/20/89 to assure appropriate notification.

CAUSE OF THE NONCOMPLIANCE Station personnel perform daily cine analysis on water '

.from.the~ cooling tower basins. This analysis is not an NPDES appreved analytical method, but historical data shows that it traditionally yields slightly higher results than actually exist. .This daily test is used to monitor and  :

conservatively control the zine residual below our NPDES limit. Samples are then sent offsite for analysis per the EPA approved method. '

Daily analysis results for the period of noncompliance I were lower than the official values giving us no indication that a noncompliance had occurred. In addition, daily pumping rates, and weekly chemical usage logs indicate that the conditions during the apparent noncompliance were not significantly different from normal operating conditions. i l

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These conditions'have been shown to be within NPDES '!

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limitations repeatedly during the-1989 year. Therefore it ,

is< felt ~that the apparent noncompliance-is either the result i of-a random error, such as sample contamination, or the L result of' limitations in the daily zine testing. Recently f f ^

it has been discovered that this test can be negatively biased by cold water temperatures.

g I' DURATION OF THE NONCOMPLIANCE  !

Supporting documentation indicates the zinc permit limit was exceeded from 10/30/89 through 11/1/89. During

this.3 day period the

ine concentration was between 1.0 and 1.1 mg/1.- Approximately 37 million gallons of cooling water k was discharged at this concentration. The permit limit for [

d1scharge is 1.0 mg/1.  ;

j The. apparent noncompliance on 11/17/89 is not supported L, by our daily cine analysis, weekly metals analysis, chemical  ;

( . pumping rates, or chemical usage logs. Therefore it is our

• L contention that only one release in excess of permit ,

limitations occurred (11/1/89) for a duration of not more L than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

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CORRECTIVE ACTION t

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.No immediate corrective actions were taken because no knowledge of.the event was available at the time of the occurrence.

PREVENTION OF PUTURE OCCURRENCES-A procedure revision is already in place to compensate for cold water temperatures on daily analyses, which should

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ellow'us to collect more accurate daily cinc data; thus providing better control over the treatment process. In addition, our sampling process is being reviewed to identify potential sources of contamination. This review will be completed by January 15, 1990. ,

Both out-of-spec samples were analy=ed offsite on 11/27/89. At that time the analyst was not aware of o'ur permit limit for zine and therefore not aware that a violation had occurred. This problem has already been remedied verbally, with the analyst. To ensure timely notification, a copy of the permit limits will be sent under cover letter to the appropriate department supervision by December 29,1989.

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y1/ .In; addition, we are examining'the feasibility of {

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maintaining the:zine' concentrations.in.the cooling towers at 3 at slightly lower level in order to provide additional i

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! assurance.that the~ permit limit'will.not be exceeded.  !

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Sin e ely, l b .-

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Q M.J. McCormick, Jr.  !

Plant Manager-  !

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cci 'U.S. Nuclear Regulatory. commission Document Control Desk Washington, D.C. 20555 -

" i 9 Administrator Region I l

,1 U.S. Nuclear Regulatory Commission E475 Allendale Road

, .Kingfof_ Prussia, PA 19406- l 4

Station; Resident NRC Inspector Tom' Kenny, M.C. #NRC;

= Program Management Section~(3WH52)  ;

Permits Enforcement: Branch  !

-Watbr Management Division.  ;

f, Environmental Protection Agency

' Water Permits Section Region'III  !

841 Chestnut Building Philadelphia, PA 19107 r h

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