Conservation by sanitation ; air and water supply, disposal of waste, including a laboratory guide for sanitary engineers.

  • Richards, Ellen H. (Ellen Henrietta), 1842-1911.
Date:
1911
Catalogue details

Licence: Public Domain Mark

Credit: Conservation by sanitation ; air and water supply, disposal of waste, including a laboratory guide for sanitary engineers. Source: Wellcome Collection.

Provider: This material has been provided by the Harvey Cushing/John Hay Whitney Medical Library at Yale University, through the Medical Heritage Library. The original may be consulted at the Harvey Cushing/John Hay Whitney Medical Library at Yale University.

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    mixture, varying not only every day in the week but every hour in the day. Discharged into a stream it is, moreover, more or less diluted; as the stream rises and falls it is pushed against the bank by the current and mingling with the colder water is often delayed by the friction of the banks. After a short distance has been traversed the fluid has become so complex that any question of animal or vegetable origin of the organic matter is futile. However obtained, the products include C02, CH4, NH3, N, H20, H, H2S, S02 (?), sulphur, alcohols as mercaptan, C2H6SH, etc. Although little is known of the decomposition of the phos- phorous radicals, they doubtless add to the odors. Offense is given by the intermediate products only, and by those not food for organisms but produced by chemical reduction processes, en- zymes, etc. Therefore it is the manager's task to keep the process going forward as fast and as far as is possible, and not backward. The laboratory work of the class will depend upon the time available. The best exercise will be a test for sulphur products (either lead or zinc acetate — odor may be more delicate) or for organic acids as butyric, and for fats, soaps, etc. The chief value of this exercise will be to draw attention to investigations now going on which may change all views. See Rideal, Sewage and the Bacterial Purification of Sewage; Lafar, Vols. I and II, Chemistry of the Proteids, Gustav Mann, etc. EXERCISE XI Trade Wastes If a field trip cannot be made for collection the instructor may procure a variety from different sources. What was said of the extreme variation of sewer content is still more true of the discharge from manufacturing plants, the chemicals used in the processes, the materials themselves, often of putrescible substances, as in a tannery or a creamery;