Letters. In other words.. - Environmental Science & Technology (ACS

In other words.. William Hatfield. Environ. Sci. Technol. , 1968, 2 (6), pp 392–393. DOI: 10.1021/es60018a602. Publication Date: June 1968. ACS Lega...
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LETTERS In other words

DEARSIR: I wish to commend the American Chemical Society for the quality of the new journal ENVIRONMENTAL SCIENCE AND TECHNOLOGY. I look forward to each issue. ‘The issue for March had two very good articles, one on phosphate removal from waste water (page 1 8 2 ) , the other on phosphates and algal growth in natural waters (page 188). O n page 194 was a good article on surfactants in the Illinois River. These are very well written articles and the data on phosphate removal at Lake Tahoe is well described. However, as a member of this branch or section of the Society for many years, and as a consultant in this field, I wish to object to the prominence given in the subtitle “and the cost is moderateless than 5 cents per 1000 gallons” (ES&T,March, page 182). This cost really is $50 per million gallons and is more than the total operating costs of present secondary treatment plants of any other size except the very small ones, in which case the costs are much higher. T h e most recent published results from Lake Tahoe are in an article by R. L. C ~ l p [J. A m . Water Works Assoc., 60, 84-94 ( 1968) which summarizes the costs as follows] :

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Process

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Cost per million gallons Capital Operationiotai

Lime treatment for PO4 removal $11 Filtration after lime 17 SUBTOTAL 28 Ammonia stripping 6 Activated carbon 18 adsorption TOTAL estimated costs atTahoe 52

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$52 24 76 9

$63 41 104 15

12

30

97

149

Please note that the total cost of lime treatment and filtration is given as $104 per million gallons which is almost the same figure as the one given in ES&T on page 185 (that is 10.46 cents per 1000 gallons o r $104.60 per million gallons). My objection is not to the accuracy of your reporting but to the impression given by the headlines and the early table in the article, which dwells on how cheap 5 cents per 1000 gallons is. The total cost of PO4 removal as given by your article for a 10-m.g.d. plant is: 10.46 cents X 1000 X 10

= $1046 per day $1 046 X 365 = $382.000 annually

This cost is almost twice the annual Circle No. 30

on Readers’ Service Card

392 Environmental Science and Technolog?

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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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