ML20064L670

Proposes to Install New Demineralizing Sys Using Reverse Osmosis & Smaller Ion Exchange Resin Bed as Discussed Previously.New Process Will Pretreat City Water by Reverse Osmosis,Removing 98% of Impurities

ML20064L670
Person / Time
Site:	Pilgrim
Issue date:	03/17/1994
From:	Boulette E BOSTON EDISON CO.
To:	Landry T ENVIRONMENTAL PROTECTION AGENCY
References
94-031, 94-31, NUDOCS 9403250155
Download: ML20064L670 (2)

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BOSTON EDISON Pilgnm Nuclear Power Station Rocky Hill Road Plyrnouth, Massachusetts o236o E. T. Boulette. PhD March 17, 1994 Senior Vice President--Nuclear BECo 94-031 Mr. Ted Landry Environmental Protection Agency Waste Water Compliance Section JFK Federal Bldg Room 2113 WMM Boston, MA 02203

Dear Mr. Landry:

As discussed with you previously, Pilgrim Station would like to install a new, more efficient and economical demineralizing system for its use of city water.

The current makeup water system utilizes city water processed through an ion exchange resin bed on a portable trailer. Reject water from the makeup trailer is discharged from neutralizing sump to the PNPS discharge canal via storm drain #005. Boston Edison is proposing to install a new demineralizing system using reverse osmosis and a smaller ion exchange resin bed.

The new process will pretreat the city water by reverse osmosis, removing 98%

of the impurities. The system uses a small resin bed downstream of the reverse osmosis units. The impurities, i.e. constituents normally found in city water, are concentrated by a factor of approximately 3.3 and rejected by a waste stream that would be routed directly to the discharge canal via storm drain outfall #005, bypassing the neutralizing sump. The flow of the waste stream will be a maximum of 20 gpm, and an average daily volume of 1500 gallons, well within the NPDES permit limit of -.015 MGD. The following table ,

compares the current waste stream to the proposed waste stream: l Current Process Proposed Process ,

1 Max Waste Flow 500 gal / day 1500 gal / day pH 6.1 - 8.4 6.1 - 8.4 Chlorides (ppm) 20 65 .

.)

Sulfates (ppm) 20 65 Silica (ppm) 20 65  !

Total Organic Carbon (ppm) 30 100

^ 4 4 6 3 M o '1 5 5 9 4 0 3 1 7 PDR ADOCK 05000293 p' 0 1

P PDR j

~ ~ , _

Due to the low suspended solids,'in the city water (<1 ppm) and the micron filters in the proposed process, the suspended solids,in the waste stream will be well below the permit limit of 30 ppm (average monthly). The new system does not use any aggressive chemicals or toxic ' compounds for cleaning. Sodium meta-bisulfite is added continuously to the feed water to remove chlorine.

Membranes are cleaned using a " clean-in-place" system that allows cleaning solutions to be collected and discharged via the neutralizing sump. It is anticipated that this type of cleaning will only be done once every six to twelve months.

.i We would appreciate your written approval of our use of a new PNPS demineralizing system as described above. Please contact Mr. Robert D.  !

Anderson at (508) 830-7935 should you need further information regarding this matter.

Sincerely,  !

E Y fw o w W h E. T. Boulette Senior Vice President-Nuclear ETB/RDA/nas/DEMINERA cc: Mr. Paul Hogan Mass. Department of Environmental Protection Division of Water Pollution Control Regulatory Branch - 7th Floor One Winter Street Boston, Mass 02108 U.S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406 U.S. Nuclear' Recjiilatory Comniission '

' Attn: Document Control' Desk Washington, DC 20555 Senior Resident Inspector Pilgrim Nuclear Power Station