ML20087A503

NPDES Noncompliance Notification:On 911230 Sample Indicated That Chlorinated Water Was Being Discharged to Altamaha River.Caused by Failure of Valve Which Isolates Chlorine Addition Sys from Svc Water Sys Intake.Valve Replaced

ML20087A503
Person / Time
Site:	Hatch
Issue date:	01/03/1992
From:	Hobson C GEORGIA POWER CO.
To:	Hedges L GEORGIA, STATE OF
Shared Package
ML20087A489	List: ML20087A486 ML20087A503
References
NUDOCS 9201090184
Download: ML20087A503 (3)

Text

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~~ TEL NO:4045267063 4391 P01 -

JA+03 '92 FR1 - 15:59 IDiFOSSIL 6 HYDRO Geo'g4s Power Company 333 hoomont Avgnyt Alienta,Geo'p;e 30308 lelephone 404 526-6t26 Meilmg Adoress:

- H>st ottce Dox 4545 l- Aftents. Georg.e 30302 Georgia Power tre so#ern *ccic sprem Ctwls M.Hobson

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ucensing eno compliance .7anuary 3, 1992 PIANT MATCH

. NPDES Permit No. GA0004120 I Mr. Lawrence W. Hedges Program Manager Industrial Wastewater Program 205 Butler Street, S.E., Room 1070 Atlanta, Georgia 30334

Dear Mr. Hedges:

In_accordance with Part II.A.2. of the above-referenced NPDES parait, attached is a report of the circumstances of the chlorine exceedance which was reported to Mr. Michael S.

Creason by telephone on December 30, 1991.

If you have questions or comments, please advise.

Yours very truly,

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( 4/ 5-C. M. Hobson GNG:el Attaohtent xct Mr. Michael S. Creason, south Unit Coordinator Mr. Larry P. Klost, Environmental Enginear L

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Plant E. I. Hatch NPDES Permit No. GA 0004120

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Descriotion of Event A weekly sample from the Unit I final discharge mixing chamber (OSN 01) taken at 0905 hours0.0105 days <br />0.251 hours <br />0.0015 weeks <br />3.443525e-4 months <br /> on 12/30/91 indicated that chlorinated water was being discharged to the Altamaha River with a total residual chlorine (TRC) concentration of 1.4 parts per million (ppm) and a free available chlorine concentration (FAC) of 1.2 ppm.

No specific chlorine limits for OSN 01 are specified in the NPDES Permit.

However, the permit does require an increased sampling frequency at OSN 01 of once per 15 minutes during periods of chlorinated water discharge.

A measurable chlorine concentration at OSN 01 was not expected and, therefore, this increased sampling frequency was not being performed prior to the analysis of the weekly sample. An increased sampling frequency was initiated upon discovery of the measurable chlorine concentration.

Cause of Event The direct cause of the evert was an internal failure of the valve which isolates the chlorine addition system from the Unit I service water system intake. The chlorine addition system serves the service water intakes for both Unit 1.and Unit 2. Due to the valve failure, the Unit I service water system was receiving an unintentional chlorine treatment during a planned chlorine addition to the Unit 2 service water system. The Unit I service water system was aligned at the time to discharge directly to OSN 01.

Period of Event The discharge of chlorinated water began at 0730 when the Unit I service water system was first aligned to discharge _directly to OSN 01. At 1000, following identification of the failed valve, the chlorine addition to the service-water systems was terminated. TRC and FAC concentrations at OS4 01 both decreased to <0.1 ppm by 1040. The time of chlorine discharge through OSN 01 was approximately 190 minutes. ,

i Actions Taken to Prevent Recurrenga

1. The failed plant service water chlorine addition valve has been replaced.

2. The corresponding valve for Unit 2 will be inspected for similar  ;

conditions as was found on Unit I within the next 30 days, l

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'3. " As an additional measure to preclude an unplanned discharge of chlorine from the site due to'an undetected valve failure, chlorine will ~ normally be _ added to a 31 ant service water system on1g,when the service water systems of bot 1 units are aligned to discharge to-the circulating water: system of the respective unit. At times _when

! chlorination _of the plant service water system is required and the above alignment is not possible (e.g., with either unit's plant service water system ~ being diverted directly. to the final discharge mixing chamber) then sampling will be performed at the-final discharge mixing chamber of both units to verify that_the chlorine addition is occurring only on the desired unit's plant service water system.

4. Chlorination of the plant service water systems for both units has been suspended until the necessary operating procedures have been modified as described above.

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