utility, industrial, and government customers for these services have benefited in terms of improved quality of the monitoring data, increased percentages of valid data collection, and a host of other specialized monitoring program services provided at the minimum possible cost. Howard M. Ellis, Presldent Enviroplan, Inc. Rutherford, N.J. 07070
If you want the latest facts on Electrostatic PreciDitators. send for this fre; book!
Water monitoring Dear Sir: We just completed a multiclient study, “Instrumentation and Process Control for Analysis and Control of Water Quality”. We forecasted that the markets for instrumentation and process control systems for the analysis and control of water quality will total over $4 billion during the 1976-85 period. The forecasts were made for (1) analytical instruments, (2)conventional instruments and control systems, (3) final control devices, and (4) computers and telemetry. In addition, markets were forecasted for various individual analytical and specialty instruments, as well as for other product categories. Seven market sectors relating to water quality were evaluated and market projections were made for each sector. These included: (1) municipal water treatment, (2) municipal water distribution, (3) industrial water treatment, (4) municipal wastewater collection, (5)industrial wastewater treatment, (6) municipal wastewater treatment, and (7) water quality monitoring. The markets for the various instruments and process control systems will vary, but will average about 11 YOI y during the 1976-85 period. In addition to the above study, we conducted a multiclient study entitled, “Industrial Water Pollution Control-US. Markets and Technology,” last year. The price of the instrument study is $1200 per client. Robert E. De La Rue, President Robert E. De La Rue Associates
United McGill is offering an important new publication devoted entirely to the subject of Electrostatic Precipitators. Fifty pages of text (with over 100 color photographs and illustrations) detail the construction, operation and capabilities of United McGill’s unique EP. The categories covered are -Solving your air pollution control problem Mobile EP’s and Testing Labs Modular EP construction Fundamental concept of United McGill’s EP and comparisons with conventional designs Electrical aspects Flow distribution considerations Sizing an EP and fi Subassemblies. T h e book also includes useful conversions to the International System of Units, a Glossary of air pollution control/EP terminology and an Index to key words in the text. If you want the latest facts on Electrostatic Precipitators, send for your free copy today. Simply fill out the coup attach it to your letterhead and drop it in the mail.
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Santa Clara, Calif. 95051 Opacity correction Dear Sir: I would like to correct one of the sketches used to illustrate the feature, “Clearing the Opacity Issue” (€S&T, June 1977, pp 561-563) in order to clear up any confusion. The caption under the sketch labeled Altitude states, “Due to sunlight scattering, visual opacity increases as the sun’s altitude increases. In summer, the altitude of the sun at noon is 79’; in winter, 33’; spring 56’ and fall 34’.” The last clause is in error, the altitude of the sun at noon in the fall (at the autumnal equinox) is not 34’. In the caption I submitted I stated “In spring and fall, the sun’s altitude at noon is 56’ at 34’ North Latitude.“Therefore, in the sketch itself, the label “fall” should not have been attached to “winter sun” but to the “spring sun.” The relationship of the sun’s altitude to opacity is quite significant. A perfect observer who read 56% opacity at noon in winter, would read 75% opacity in Volume 11, Number 9, September 1977
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Environmental Science & Technology
spring or fall and 85% opacity in summer, all other factors being constant. A minor error was also observed in Table 1. The heading of the third column should read “No. within 7.5 ?h opacity of meter reading”, rather than ”No. with 7.5% opacity. . .”. Thus, in only 17 times out of 94 were EPA observer’s opacity readings within 7.5% opacity of the transmissometer reading. Alex Weir, Jr. Southern California Edison Co. Rosemead, Calif. 91770 Opacity controversy Dear Sir: I am deeply disturbed by the continuing controversy in your magazine concerning plume opacity and visual effects. In my opinion, the two feature articles by Dr. Alexander Weir, Jr. (“Factors Influencing Plume Opacity,” June 1976, p 539; “Clearing The Opacity Issue”, June 1977, p 561) serve no constructive purpose in the dissemination of information on the subject, but through misconception and misrepresentation attempt an indictment of visual opacity as a regulatory option. The primary misconception in the June 1977 feature is that an industry’s failure to meet NSPS opacity standards while complying with mass emission standards will result in the expenditure of millions of dollars in additional control equipment to meet the opacity limit. Perhaps the author should read 40 CFR 60.11, which specifies the procedure to be followed in appealing to the EPA Administrator for an adjusted opacity standard, which will be established upon demonstration of the source operator that control equipment was being properly maintained and operated at the time of the opacity excursion. A new opacity standard will be established that the source will be able to meet all times during which the source meets the applicable mass emission standard. The author’s emotional appeal to consumers that opacity regulation will increase prices of concrete, steel, and electricity because of additional controls to meet a visual standard is simply not valid, as the FederalRegisterwill indicate to all who will read it. Dr. Weir’s statements on the effect of sun angle or altitude on visual opacity can be refuted by data collected by the Texas Air Control Board during Visible Emissions Evaluation courses, which are given twice yearly at each of six locations across Texas. For example, the Corpus Christi course is held in December and June, so an observer training in December should be reading higher opacities on the same plume in June because of the higher sun angle. Since most observers requalify in June on the first set of readings, apparently no bias exists because of sun altitude. The field experience of hundreds of Method 9 opacity evaluators simply does not support his supposition. The examples cited here are but two of the many mistaken and misleading assertions made by the author in the cited articles. I believe your magazine is remiss
in sponsoring the publication of these articles, which unfortunately by their very publication in a prestigious journal such as €S&T gain unwarranted credence. I would hope that the EPA will be invitedto submit a feature article in which any damage done by Dr. Weir might be repaired. John W. Key Texas Air Control Board Austin, Tex. 78758 Financing pollution control Dear Sir: In the April issue ( E S T , April 1977, p 329) you incorrectly say that the Small Business Administration (SBA) will guarantee tax-free municipal bonds. The SBA will guarantee the payment of the financing contracts, which are the security for the bonds. There is an important difference that will be noted by your rqore sophisticated readers. California expects to shortly sell about $5 million worth of bonds for its pilot program. James H. McCall California Pollution Control Financing Authority Sacramento, Calif. 95814 Nuclear radiation Dear Sir: The letter by Andrew P. Hull ( E S T , April 1977, p 326) regarding our reply (€SAT, December 1976, p 1185)to the Currents (€S&T, August 1976, p 730) report of our atmospheric tellurium-132 research fails to recognize the significant points of the communication. The purpose of our earlier reply was to state that our data showed no evidence of the Hanford nuclear facilities being the source of the tellurium-132, as was inadvertently implied in the Currents report. The concentrations of ls2Te were mentioned in the reply solely for clarification and were not reported as research results since there is no space for concomitant data interpretations. However, a detailed technical report concerning this research project is available upon request from the authors. S. 0. Farwell S. J. Fernandez Washington State University Pullman, Wash. 99163 NO, in boilers Dear Sir: In your informative article on Exxon’s Thermal Denox Process ( € S T , March 1977, p 226), it is stated that the sulfuric acid dewpoint in boilers is generally around 180 O F . Hopefully, this is just a typographical error on your part. Actually, you meant to say 180 OC. This corrected value would agree with the fact that the sulfuric acid dewpoints generally range between 130-180 OC for residual oil or coal-fired boilers. The exact dewpoint is dependent on the SO3 and water vapor in the flue gas. Richard C. Diehl Calgon Corp. Pittsburgh, Pa. 15230
