Report on an examination of Schutzenberger's process for the estimation of dissolved oxygen in Thames water / by Henry E. Roscoe.
- London County Council
- Date:
- 1889
Licence: Public Domain Mark
Credit: Report on an examination of Schutzenberger's process for the estimation of dissolved oxygen in Thames water / by Henry E. Roscoe. Source: Wellcome Collection.
Provider: This material has been provided by London School of Hygiene & Tropical Medicine Library & Archives Service. The original may be consulted at London School of Hygiene & Tropical Medicine Library & Archives Service.
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![Carbonic acid deter inination. Effect of diffusion on the gases in the z'iv’er. acquired oxygen in the rain water, accounts for the expulsion of part of the nitrogen. Thus the carbonic acid determination becomes of importance as giving an indication of the amount of recently oxidised organic matter, and samples of water from Crossness might with advantage be examined from time to time by the absolute method. The natural tendency of such impure waters, especially those of March 5th, 6th, and 7th, containing little oxygen (independently of the action of organisms), is to lose the excess of carbonic acid by diffusion into the air, and to regain by atmospheric aeration the original proportion of oxygen shown in the Eichmond water. AVhilst speaking of the absorption, by the impure water at Crossness, of the oxygen naturally dissolved in the purer water higher up the river, it may be well to obtain an idea of the action exercised by a heavy fall of rain on the natural purification of the river, as com- pared with the artificial addition of oxygen by means of manganate of soda. For this purpose the sum of money may be calcu- lated which must be spent in manganate to give to the river as much oxygen as is dissolved in the fresh water coming over Teddington Weir in one day. On November 27th, 1883, 4,187,500,000 gallons of water passed over the Weir, and this may be supposed to contain icc. of oxygen per litre,* or 0‘7 grains per gallon. This corresponds to 418,750 lbs., or nearly 187 tons of oxygen per diem, and this is equivalent to t / ,713 tons of manganate, the cost of which, at £‘8 per ton, amounts to £61,704 ; this sum representing the purifying value of the fresh water flowing over Tedding- ton Weir on this particular dav, expressed in terms Sf tlie available oxygen contained in manganate of soda. The average daily flow over Teddington Weir for July, 1886, was 596,000,000 gallons, equivalent to 59,600 lbs! or 26 6 tons of oxygen on the same basis. This is equivalent to 1,097| tons of manganate, or £8,778 per diem during July, 1886. The flow of fresh water over the AVeir is seldom below one-third this amount. riiewater at llichmond in February contained t lo furnish 1 ton of oxygen, 411 tons of required. 8cb.c. per litre.] manganate are](https://iiif.wellcomecollection.org/image/b24766380_0008.jp2/full/800%2C/0/default.jpg)
