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 Bromley]
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Average results of the Chemical and Bacteriological examination of the water supplied to Bromley during the year 1956. Milligrammes per litre (unless otherwise stated).
Shortlands Well No. 1 | Shortlands Well No. 2 | West Wickham Well | Orpington Well | North Orpington New Bore Hole | North Orpington Well No. 1 | Thames-derived filtered water | |
---|---|---|---|---|---|---|---|
Chemical | |||||||
No. of samples | 4 | 4 | 5 | 3 | 3 | 3 | 1598 |
Ammonia Nitrogen | 0.001 | 0.005 | 0.003 | 0.003 | 0.007 | 0.002 | 0.0036 |
Albuminoid Nitrogen | 0.024 | 0.025 | 0.022 | 0.018 | 0.020 | 4.7 | 0.086 |
Oxidised Nitrogen—Nitrate | 4.8 | 5.1 | 5.4 | 6.2 | 5.3 | 4.7 | 4.3 |
Chlorides as Cl. | 16 | 16 | 13 | 15 | 16 | 12 | 30 |
Oxygen abs. from Perman ganate 4 hours at 27°C. | 0.08 | 0.06 | 0.04 | 0.10 | 0.06 | 0.06 | 0.3 |
Turbidity in terms of Silica | Nil | Mil | Nil | Nil | – | Nil | 13 |
Colour m.m. brown 2ft. Tube Burgess's Tintometer | 282 | 282 | 260 | 278 | 258 | 262 | 258 |
Hardness (Total) | 74 | 72 | 48 | 36 | 42 | 72 | |
Hardness (non-carbonate) | 7.2 | 7.2 | 7.1 | 7.1 | 7.3 | 7.1 | 7.7 |
Phosphate as P.O4 | – | – | – | – | – | – | 0.90 |
Silicate as SiO2 | — | – | – | – | – | — | 10 |
Sulphates as SO4 | — | – | 4 | 16 | 8 | 8 | 58 |
Conductivity | 40 475 | 40 500 | 400 | 475 | 425 | 450 | 500 |
Bacteriological Results
Shortlands Wells | West Wickham Well | Orpington Well | North Orpington Wells | Thames-derived filtered water | |
---|---|---|---|---|---|
Before Chlorination No. of samples | 499 | 232 | 251 | 146 | 7086 |
Plate count (Average per millilitre) Colonies counted on Agar : 37°C. (20-24 hours) | 0.01 | 0.01 | 0.3 | 4.7 | – |
Bact. coli test: Percentage samples negative in 100 ml. | 100.0 | 100.0 | 99.6 | 13.7 | 61.2 |
Average number per 100 ml. | – | – | 0.02 | 17.86 | 4.43 |
After Chlorination (Water passing into Supply). No. of Samples | 255 | 236 | 256 | 149 | 3736 |
Plate count (Average per millilltre) Colonies counted on Agar: 37°C (20-24 hours) | – | – | — | – | – |
100 ml. | 100.0 | 99.6 | 100.0 | 100.0 | 99.9 |
Average number per 100 ml. | – | 0.013 | – | – | 0.002 |