A manual of practical hygiene : intended especially for medical officers of the Army and for civil medical officers of health / by Edmund A. Parkes.

Date:
1873
Catalogue details

Licence: Public Domain Mark

Credit: A manual of practical hygiene : intended especially for medical officers of the Army and for civil medical officers of health / by Edmund A. Parkes. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

    22/746 (page 18)
    Page 336—Removal of Excreta—Since the chapter on Removal of Excreta was in print, the “Fourth Report of the Committee of the British Associa- tion on the Treatment and Utilization of Sewage ”* has been published, and contains numerous valuable analyses by Dr Russell. I need only notice the following processes:— 1. Messrs Weare’s process of charcoal filtration as carried on at the Stoke Union Workhouse.—The sewage from water troughs is filtered through successive chambers of vegetable or peat charcoal; the analyses show a con- siderable purifying effect, the ammonia being reduced from 24*01 parts per 100,000 to 2T5, and the organic nitrogen from 4*94 to *63; the suspended matters were entirely removed, and the dissolved solids reduced from 163*8 to 68*9 per 100,000. The effluent water had still, however, a strong smell of sewage ; there was no oxidation into nitrates or nitrites. 2. General Scott's cement process at Ealing (see page 354).—The com- mittee gives analyses which show that the suspended matters are precipitated very completely by General Scott’s process; the effluent water contained rather more than frds of the chlorine and Jths of the dissolved nitrogen ; the ammonia was reduced to one quarter, but the “ organic nitrogen ” was nearly doubled. Some oxidation into nitrates had taken place, the effluent water was therefore valuable as an irrigator. 3. Whittlireadls patent (precipitation by dicalcic and monocalcic phosphate, see page 353) was found to give good results in removing suspended matters and “ organic nitrogen,” and the committee consider the process deserves “ further investigation.” 4. Dry earth system.—The committee gives the following analyses by Dr Gilbert:— Before use. Used once. Used twice. Used three times. Percentage of nitrogen in soil dried at 212° . *073 *240 *383 *446 The committee repeat, therefore, that “ such a manure, even if disposed of free of charge, would bear carriage only to a short distance.” 5. Merthyr-Tydfil Sewage Farm (see page 354).—The ordinary flow of dry weather sewage was found to be 650 gallons per minute, and the outflow 1425 gallons per minute, chiefly from the influence of percolation from the neighbouring river; the suspended matters were removed; the ammonia and the nitrogenous matters in solution were almost completely oxidised into nitrates and nitrites; the sewage, therefore, was “satisfactorily purified.” 6. Bretons farm near Romford.—A great number of analyses of the sewage and effluent water, and determinations of the amount of nitrogen taken up by the crops, are given in this part of the report. The general results were that “ less than 11 per cent, of the total nitrogen in the sewage escaped in the effluent water, and of that only a fractional percentage in an organic form, and upwards of 40 per cent, was actually recovered in the crops grown on the land.” There was thus, therefore, very satisfactory purification and utilisation as well. Page 345, line 2—for “the pipe should not be” read “ the pipe should be.” Page 353, line 11—for “Whitehead” read “ Whitthread.” Page 355—footnote—last line but one—for “editors” read “2d edition.” Page 367, line 18—for “ In 1859 ” read “ In 1869.” Page 373, line 14—for “page 369 for the Air Purifiers” read “page 128.” * Published by Taylor and Francis, Red Lion Court, 1873.