The purification of sewage and water / by W.J. Dibdin.

Date:
1897
Catalogue details

Licence: Public Domain Mark

Credit: The purification of sewage and water / by W.J. Dibdin. 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.

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    the works, although there was a considerable evolution of gas, no trace of sulphuretted hydrogen was detected, there being practically an entire absence of odour from the gas as it issued from the burner placed on the top of the septic tank. Septic Tank System of Seicage Treatment.—Exeter (Belleisle) Installation. —Summary of Analyses. Grains per gallon. Ammonia. Nitrogen. Suspended Dissolved p c3 .i.H d 3 k jwiiua, 1 1 April and June, 1897. Oxygei absorbed f permanga] in four hoi Free. Albuminoid Chlorine As nitrites. As nitrates. Total. Mineral. Organic. Total. Mineral. Organic. Crude sewage, aver- i age of 12 samples .. j 2-028 3-778 0-212 5-0 — — 24-5 1 10-0 14-5 29-9 14-0 15-9 Tank effluent, aver- i age of 13 samples.. | 1-405 2-763 0-175 5-1 — — 10-8 3-5 7-8 30-7 16-1 14-6 Purification per i cent i 30-8 26-9 17-5 Filtrate, average of i 19 samples > Purification on , 0-388 1*705 0-078 5-3 0-253 0-353 Pra ctic nil. ally 44-5 20-3 24-2 tank effluent j per cent ’ Purification on \ 72-4 38-3 55-5 crude sewage > per cent ' 80-9 54-9 63-2 I made a careful series of measurements to ascertain the depth of deposit at the bottom of the tank, which had not been emptied, or in any way cleared out, since it was started on the 15th August last, exactly six months previous to the date of inspection. The result was to show that the line of demarcation between sludge and water was about 15 in. from the bottom of the tank. At the first or grit-intercepting chamber, which forms part of the septic tank, there was about 2 ft. of grit in one corner but very little elsewhere, so that it is evident that the efficiency of the tank in this re- spect had not been in any way impaired by the ten months’ work. It is evident, moreover, that when the deposit becomes