ML20086F815

Environ RO 77-8:on 770217,total Suspended Solids for Sewage Plant Effluent Exceeded ETS Limit.Caused by Sys Upset Brought About by Reduced Bacterial Action within Activated Sludge Aeration Tank

ML20086F815
Person / Time
Site:	Peach Bottom
Issue date:	02/25/1977
From:	Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Stello V Office of Nuclear Reactor Regulation
References
RO-77-8, NUDOCS 8401090301
Download: ML20086F815 (2)

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.j PHILADELPHIA ELECTRIC COMPANY 2301 M ARKET STREET P.O. BOX 8699 ,

PHILADELPHI A. PA.19101 saim e414ooo 1 gMLE cou 1 February 25 , 1977 >al~ <

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Mr. Victor Stello, Jr. ,y 9, Otractor 5-Division of Operation Reactors Office of Nuclear Reactor Regulations s j.

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l U.S. Nuclear Regulatory Corsaf ssion y Washington, DC 20555 Dear Mr. Stello

SUBJECT:

ENVIRONMENTAL DEVIATIg 9

The following deviation was reported to Mr. Walt Baunack, Office i

of Inspection and Enforcement, Region I, United States Nuclear Regulatory

Consnission on February 18, 1977 l

Reference License Number DPR-44/56 Appendix B Environmental Techn'ical Specifications: faction 2.2 3 R epor t No.: 50-277/278-77 8 Report Date: February 25, 1977 l Deviation Date: February 1/,1977 Facility: .-

Peach Bottom Atomic Power Station i Units 2 & 3

, R . D. 1, De l t a, PA 17314 Identification of Deviations l The total suspended solids for the Unit 2 and 3 sewage plant af fluent exceeded the Environmental Technical Specification 2.2.2 limit. .

Conditions Prior to Deviationy The sewage plant was in the autoeestic mode.' ^

t Description of Deviations i On February 17, 1977, the daily turbidity measurements and l other operating parameters indicated a degradation in the quality of I

the Unit 2 and 3 sewage plant biota leading to a high total suspended solids level of a continuous nature. Several samples were taken each

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Mr. Victor Stollo, Jr.

O O 50:277/278-77 8 s

February 25, 1977 Page 2 day thereaf ter until February 22, 1977 The gross suspended solids level ranged from a low of 43 8 ppm to a high of 548 ppm with an average of 122 ppm. The average river water total suspended solids level during the period was 5 54. This problem continues.

Designation of Apparent Cause:

A system upset brought about reduced bacterial action within the activated sludge aeration tank. The resultant sludge did not floc and settle properly. This, coupled with greater than normal water in-put due to the Unit 3 refueling outage, created the high total suspend-ed solids in the system effluent. The cause of the upset is under in-vestigation.

Analysis of Deviation:

Because the sewage plant flow is diluted by a f actor of 50,000 with circulating water flow, the suspended solids of the circulating water leaving the discharge canal was not greatly af fected. Theref ore, the environmental impact was minimal.

Corrective Action:

Initially the problem wasthought to have been caused by higher than normal input flow which pronpted cleaning of the chlorine contact tank. However, degradation of the activated sludge and foaming in the aeration tank indicated problems with the bacterial colonies. Some of the old sludge was then pumped from the aeration tank, which should allow the bacteria to recover and form sludge that will floc and settle properly. Design changes that will eliminate the high flow periods that aggravate the carry over problem are under investigation. To establish the cause of the system upset, we have asked our consultant to investigate and supply technical advice for prevention of further incidents.

Failure Data . . .m 50 277/278-77-4, 50-277/278-7f-2, 50-277/278-77-14, 50-277/

178-76-44, 50-277/278-76-37, 50-277/278-76-34, 50-277/278-76-26, 50-277/

J/8-76-7, and 50-277/278-76-6.

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Very truly yours,

.J.

Cooney /  ;

3 rintendent '

Generation Division-Nuclear l

cc: Mr. J. P. O'Reilly -

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