View report page

Table 17
Average results of the chemical and bacteriological examination of the water supply to the Borough of Lewisham for 1963
milligrams per litre (unless otherwise stated)
Description of the
Sample
No. of
Samples
Ammoni-
acal
Nitrogen
Albuminoid
Nitrogen
Nitrate
Nitrogen
Chlorides
as CI.
Oxygen
abs.
from
KMn04
4 hrs.
at27°C.
Turbidity
units
Colour
(burgess)
scale
Hardness
(total)
Hardness
(noncarbo
nate)
PH
value
Phosphate
as
PO4
Silicate
as
SiO2
Sulphate
S04
Magnesium
as
Mg.
Natural
Fluoride
as F.
Surface
active
material
as
Manoxol
OT
Sodium
as
Na.
Potassium
as
K
Electrical
Conduc
tivity
(microm
hos)
Bexley well
9
0.007
0.018
4.3
19
0.10
Nil
Nil
316
70
7.1
13.0
2.1
580
Darenth well
5
0.010
0.015
4.8
18
0.02
Nil
Nil
266
32
7.1
11.0
1.9
480
Deptford well
4
0.005
0.020
6.0
40
0.08
Nil
Nil
354
110
7.2
25
5.1
700
Wilmington Well
3
0.016
0.016
6.9
23
0.20
0.1
Nil
282
44
7.2
15
2.2
550
Thames-derived
South of River
156
0.20
0.079
3.8
32
1.18
0.3
10
266
66
7.8
1.3
11
62
5
0.25
0.08
550
Table 18
Bacteriological Results—Yearly Averages, 1963 of water supplied to the Borough of Lewisham
Source of supply
BEFORE TREATMENT
AFTER TREATMENT
Number
of
samples
Agar plate
count per ml.
Coliform count
Escherichia coli
count
Number
of
samples
Agar plate
count per ml.
Coliform
count
E. coli.
count
20-24
hours
at
37°C
3 days
at
22°C
Per cent.
samples
negative
in
100ml.
Count
per
100ml.
Per cent
samples
negative
in
100ml.
Count
per
100ml.
20-24
hours
at
37°C
3 days
at
22°C
Per cent.
samples
negative
in
100ml.
Per cent.
samples
negative
in
100ml.
Bexley well
251
2.9
32
99.60
—
100.0
—
256
0.1
4
100.0
100.0
Darenth well
251
0.0
10
99.20
—
99.20
—
255
0.0
5
98.43
100.0
Deptford well
251
0.2
18
98.80
—
99.60
—
255
2.3
102
100.0
100.0
Wilmington well
197
0.2
51
97.97
—
99.49
—
198
0.0
45
99.48
100.0
Thames-derived South of River
1.873
12.5
—
99.41
99.47
24