[Report of the Medical Officer of Health for Chislehurst] page 30

Chislehurst 1954

[Report of the Medical Officer of Health for Chislehurst]

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Table: BACTERIOLOGICAL RESULTS

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BACTERIOLOGICAL RESULTS

	Orpington Well	N. Orpington Well	Shortlands Well	Eynsford Well	Bexley Well	Wilmington Well	Darenth Well	Thames derived filtered water
Before Chlorination (Raw Water)
Number of samplesPlate Count (Average per millilitre)	246	231	504	257	572	477	136	7222
Colonies counted on Agar:
22°C. (3 days)	1478.7	42 0	21	18 4	5.6	51.2	29.8	Nil
37°C. (20-24 hours)	101 0	4.6	0.2	0.1	0.1	0.3	0.8	Nil
Bact. coli test:
Percentage samples negative in 100 ml.	100 0	22.9	100.0	100.0	100.0	100.0	100.0	62.2
Average number per 100 ml	Nil	11 70	Nil.	Nil	Nil	Nil	Nil	3.45
After Chlorination (Water passing into Supply)
Number of samples	257	235	257	265	306	252	236	3604
Plate Count (Average per millilitre) Colonies counted on Agar:
22°C. (3 days)	Nil	Nil	Nil	Nil	Nil	Nil	Nil	Nil
37°C. (20-24 hours)	01	Nil	Nil	Nil	Nil	Nil	Nil	8.8
Bact. coli test:
Percentage samples negative in 100 ml.	100.0	100.0	100.0	100.0	100.0	99.6	99.6	99.8
Average number per 100 ml.	Nil	Nil	Nil	Nil	Nil	0.008	0.008	0.004