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LETTERS Process measurements Dear Sir: I would like to call your attention to the omission of TRW’s role in the implementation of the Process Measurements for Environmental Assessment Symposium (ES&T , May 1978, p 513). T R W was funded by EPA to run the symposium. Most of my coordinating activities for the implementation of the symposium were performed when I was employed by T R W ; since January 1978, T R W has provided a subcontract to me at Systems, Science and Software (S-Cubed) to assure continuity in the implementation of the symposium. Through an EPA contract, T R W clearly was financially responsible for the symposium. In addition, many hours of T R W employees were spent in behalf of informing the attendees of the symposium and the topics to be covered
participating in the social activities planned, and performing the needed work of manning registration desks, providing visual aid support, and assuring things went well. E. A. Burns Systems, Science and Software La Jolla, Calif. 92038
Toxin removal-correction Dear Sir: I n the feature article, “Target: Toxin Removal” ( E S &T, May 1978, p 533), under the heading “Chemical oxidation”, it was misstated that :“Hydrogen peroxide and potassium permanganate would result in an oxidized by-product plus manganese dioxide”. The corrected statement should read, “Hydrogen peroxide and potassium permanganate could also feasibly be used to oxidize toxins. The use of potassium permanganate would result in an oxidized by-product
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plus manganese dioxide which is relatively insoluble in water.” Anthony V. Metzner Ecod yne Union, N.J. 07083
Power plant chlorination Dear Sir: The figure in ES& T, July 1978, on page 781, shows “hot side” blowdown. This has been proscribed by 40 CFR 423 for all electric generating units constructed after 1974. The circulating cooling water system blowdown should be taken off between the cooling tower and makeup water injection. Hot side blowdown has the further disadvantage of wasting directly to blowdown some 10-50% of the excess chlorine passing the condenser. This chlorine should be used to maintain biological cleanliness in tower. As Zeitoun and Reynolds correctly pointed out, algae are the dominant problem in the tower; and it will
