Hints from the Health Department. Leaflet from the archive of the Society of Medical Officers of Health. Credit: Wellcome Collection, London
[Report of the Medical Officer of Health for Twickenham]
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Table 7
Results of the Chemical and Bacteriological Examination of the Water Supply to the Borough of Twickenham for 1956
Parts per million (unless otherwise stated)
Description of the Sample | Number of Samples | Ammoniacal Nitrogen | Albuminoid Nitrogen | Oxidised Nitrogen (Nitrate) | Chloridesas C1 | Oxygen abs. from Permanganate 4 hrs. at 27 °C. | Turbidity, in terms of Silica | Colour, mm. brown, 2 ft. tube, Burgess's Tintometer | Hardness {total) | Hardness (Non-carb.) | pH. Value | Phosphate as P.O 111/4 | Silica as SiO2 | Sulphates as SO4 | Electrical Conductivity (gemmhos.) |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
River Thames water filtered at Hampton Works | 225 | 0.024 | 0.087 | 4.1 | 30 | 1.16 | 0.3 | 13 | 258 | 72 | 7.7 | 0.90 | 11 | 58 | 475 |
Description of the Sample | Number of Samples | Plate count (average per millilitre) Colonies counted on agar after 20-24 hrs. at 37 °C. | Bact. coli test | |
---|---|---|---|---|
Percentages of samples negative in 100 ml. | Average number of Bact. coli per 100 ml. | |||
River Thames water filtered at Hampton Works | 985 | 3.7 | 100.0 | Nil |