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cost of operating a standard 10 n1.g.d. secondary treatment plant. Thus, when such advanced treatment is necessary it will triple the cost of present secondary treatment. The Dow Chemical treatment, which 50 far has shown a 70-80% removal, is perhaps cheaper. But I have seen no place where they have given the additional cost due to additional sludge handling. increased sludge digestion tanks, or incineration costs. A t least one third of the cost of sewage treatment is in the handling of the sludge which is produced. The article by Ferguson on algal growth and nutrients (page 188) is an excellent summary and is an article which does not give any false propaganda about the terrible condition of our surface waters. Algal blooms in our lakes have existed before phosphates were ever used i n our detergent mixtures and some of the present publicity is propaganda with very little scientific background. It is doubtful if the removal of 90% of the phosphorus in sewage effluents will sufficiently reduce algal growth to be worth the cost. William D. Hatfield L)rcYlffft., Ill.
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Myopia or short term
DEARSIR : I feel compelled to write to you to voice objection to the title of Mr. Ferguson’s paper, “A Nonmyopic Approach to the Problem of Excess Algal Growth,” in the March issue (ES&T: page 188). T h e title infers that a host of people who have spent many years of their lives in study of the problem are suffering from myopia simply because they are attempting to do something constructive to relieve the situation. There is always room for a difference of opinion, but there is not room for “headline hunting” titles in professional publications. There is an element of heme in Mr. Ferguson’s paper, but to suggest that we postpone all preventive action because there may be a few isolated cases which do not seem to fit the general pattern is to “beg the question.” Many of these result from “fair weather” or short term investigations which lead to unjustified conclusion\. In my experience. every study has pointed to nitrogen and ’or phosphorus as the prime nutrients, regardless of their origin. In my opinion. if we are to be accused of myopia. it should be because we are attacking phosphorus alone and not both phosphorus and nitrogen. I predict the latter will be within five years, also. Clair N. Sawyer Bo.s/orr, MrLSs.
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Yolume 2, Number 6,Julie 1968 393 .
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