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Purification of the Washington water supply
Purification of the Washington water supply Author:United States Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: Professor Mason. Is that for the whole run ? Dr. Woodward. Yes, regarding, however, December 27 as the end of the fourth run of the slow sand filter, as indic... more »ated by page 52 of Colonel Miller's report, but even including the figures for the beginning of the fifth run when the filter was undoubtedly polluted as result of use from December 27 to January 5. Without reference to, or considering the two experimental filters, but simply for the sake of the argument, is it not the number of bacteria in the effluent and not the number left in the filter that indicate the danger in the water? Professor Mason. Yes; as to the general proposition you are right: That if you have more bacteria present in the effluent from filter A than you have in the effluent from filter B, of course the danger will increase with the number of bacteria in the water. There is no doubt about that. Dr. Woodward. And probably in proportion to the two. Professor Mason. Provided you do not get those numbers too small. STATEMENT OF ALLEN HAZEN. Mr. Moore. Mr. Hazen, with what filtration work have you been connected ? Mr. Hazen. I was connected at first with the Lawrence Experiment Station of the Massachusetts State board of health. The Lawrence city filter was built in 1892, and was put in operation in September, 1893. Also I have been connected as engineer with the construction of filter plants at Far Rockaway and at Red Bank, and with the Albany filter plant and with the Superior Water, Light, and Power Company at Superior, Wis., and a plant for the Pennsylvania State Insane Asylum at Harrisburg. I have also designed other filters and have made many investigations and tests of filters in service. Mr. Moore. You are the author of a treatise on the purification of water, the latest edition ...« less