ML20078G842

Submits Response to Violations Noted in Insp Repts 50-338/94-10 & 50-339/94-10.Corrective Actions:Upset Conditions Corrected & Facility Performance Inproved

ML20078G842
Person / Time
Site:	North Anna
Issue date:	11/09/1994
From:	Marshall B VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	Pandey J VIRGINIA, COMMONWEALTH OF
References
NUDOCS 9411160207
Download: ML20078G842 (3)

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% l November 10, 1994 VIRGINIA POWER CERTIFIED MAIL RETURN RECEIPT REOUESTED 1

1 Janardan R. Pandey j Valley Regional Office 1 Department of Environmental Quality P. O. Box 268 Bridgewater, VA 22812 RE: NORTH ANNA POWER STATION - VPDES PERMIT NO. VA0052451 NOTICE OF VIOLATION NO. 94-10-VRO-017

Dear Dr. Pandey:

This is in response to the subject Notice of Violation (NOV) delivered to North Anna Power Station on October 27, 1994. The violations listed in the NOV were those experienced as a result of separate, unrelated sewage treatment plant upsets at the package STP which discharges via Outf all 007 and the main STP, Outfall 011.

Upon discovery of the violations of permit limitations, you were notified by telephone on October 6, 1994. The explanations of the upset events were then discussed in my follow up letter dated October 13, 1994.

Since the upset events, the previous primary operator has left the company, new operators have been assigned to these facilities and operations have been changed to improve performance of all of the STPs and to help preclude recurrence of similar events. Upset conditions were corrected and facility performance improved by:

Outfall 007, Package Sewage Treatment Plant-The plant was seeded to replace the microorganism population lost during the upset and to increase biological activity.

- The mixed liquor suspended solids was increased.

A malfunctioning timer was replaced.

A failing joint on an air compressor was repaired.

Additionally, in anticipation of possible increased flows, the sister package STP (Outfall 005) was started up to be prepared to treat future influent increases.

Outfall 011, Main Sewage Treatment Plant-

- One side of the plant was shut down to increase flow to the other to 25% of design.

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l Janardan R. Pandey November 10, 1994 i Page 2 I

- One side of the equalization tank was shut down to decrease holding time before influent is processed.

Mixed liquor suspended solids was increased. i Reseeding of microorganisms was used to increase l biological activity. l Sludge was cleaned from the equalization tank sides and '

bottom.

- Aeration on/off timing was changed from 15 min./15 min. ,

to 30 min./30 min.

Plant upset recovery and performance improvements brought BOD results at the 007 STP down to 33 mg/l by 10-14-94. Results for TSS on 10-21, 10-23 and 10-24 were 33, 17 and 21 mg/1, respectively. The main STP, 011, was producing TSS of 19 mg/l on i 10-15 and 24 mg/l on 10-17. Other BOD results are not yet l available but will be reported on the appropriate DMRs.

1 As discussed in my follow up letter, the receiving waters of the STP discharges did not show any evidence of environmental problems from the discharges nor was there any indication that abnormal l discharges had occurred at any of the discharge points. The discharge rate at outfall 007 is small enough that it likely would have been quickly assimilated by the receiving waters at the subsurface outfall pipe. Any excessive solids in the Outfall 011 discharge would likely settle out again in the discharge canal or the Waste Heat Treatment Facility. No detrimental environmental damage would be expected from either discharge. We believe that both of these incidents were properly characterized as sewage i treatment plant upsets.  !

Also, during the visit for delivery of the NOV, the inspector, Mr.

C. L. Auckerman, pointed out that our maximum results had not been properly calculated. The actual highest single values had been reported on the DMR rather than weekly averages. The only item where tne proper calculation method has any significant impact is with respect to the TSS Concentration Maximum for discharge 007 listed on the NOV. This should be 43.9/45 as opposed to the 66.0/45 originally reported and is therefore not a violation of the j limitations. Corrected DMR pages for the affected outfalls have i been submitted. )

Should you desire additional information or have any questions about this matter, please contact Daniel James at (804)273-2996.

Sincerely,  !

h*)w l

)

B. M. Marshall, P.E.

Manager Water Quality l

T .

Janardan R. Pandey

-November 10, 1994 Page 3 4

i cc: U.S. Nuclear Regulatory Commission l Region II 101 Marietta St., NW Suite 2900 Atlanta, GA 30323 Re: North Anna Units 1 & 2 -

Docket Nos. 50-338/50-339 License Nos. NPF-4/NPF-7 U.S. Nuclear Regulatory Commission Document Control Desk '

Washington, DC 20555 Re: North Anna Units 1 & 2 Docket Nos. 50-338/50-339 License Nos. NPF-4/NPF-7 Mr. R. D. McWorter NRC Senior Resident Inspector North Anna Power Station 6

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