KING INSTITUTE, GUINDY, FOR 1927-28
difference between the effluents from the open and closed septic tanks. The
closed septic tank effluent was definitely the better as regards the albuminoid
nitrogen present, but was a little the worse as regards the oxygen absorbed which
is what one would expect. Since the result for albuminoid nitrogen is more
important we may conclude that on the whole the closed septic tank gave slightly
better results than did the open tank. The bacterial filter worked well judging
from the results (compare Tables II and 1II) which are well above the standards
laid down by the Royal Commission on Sewage, viz., 0.2 per 100,000 for albu--
minoid nitrogen, 2.0 parts per 100,000 for oxygen absorbed. Further there
were always plenty of nitrites and nitrates in the final effluent.
TABLE I.—Analyses of Raw sewage, Engineering College, Guindy.
Date.
Ammoni-
acal
nitrogen.
Albuminoid
nitrogen.
Oxygen
absorbed
in 4 hours.
Date.
Ammoni-
acal
nitrogen.
Albuminoid
nitrogen
.
Oxygen
absorbed
in 4 hours.
Period I.
Results are expressed in parts per 100,000.
1926.
1926.
6th July
...
0.56
0.22
1.59
4th August ..
1.15
0.34
3.29
7th "
...
1.12
0.45
1.96
9th "
...
0.84
0.48
2.73
8th "
0.53
0.22
0.75
10th "
...
0.90
0.36
2.17
9th "
...
0.78
0.34
1.48
13th "
-
0.74
0.26
2.14
12th "
...
0.50
0.28
2.02
19th "
...
0.40
0.14
0.42
13th "
...
0.64
0.24
2.13
20th "
...
1.68
0.62
5.35
14th "
...
1.08
0.34
3.10
25th "
0.48
0.31
2.03
15th "
...
0.80
0.42
2.71
31st "
...
0.25
0.14
1.72
16th "
...
1.00
0.62
3.28
2nd September.
0.66
0.26
2.15
19th "
...
0.86
0.30
1.50
7th
"
0.53
0.32
2.01
22nd "
...
1.25
0.36
2.29
8th
"
1.04
0.29
1.77
23rd "..,
1.08
0.43
2.60
14th
"
0.62
0.17
1.97
26th "
...
1.35
0.45
3.16
23rd
"
0.48
0.17
1.55
27th "
...
1.00
0.18
2.40
27th
"
0.53
0.12
0.30
28th "
...
1.02
0.34
2.65
Average of 32
samples
...
0 . 8 5
0.30
2.21
29th "
...
1.00
0.30
2.32
30th "
..
1.19
0.26
2.60
2nd August ...
1.02
0.26
2.41
Period II.
1926.
1926.
30th September.
0.52
0.25
...
16th November...
0.20
0.30
1.71
1st October ...
0.56
0.28
...
17th
"
...
0.24
0.21
1.51
4th "
...
0.92
0.24
...
18th
"
0.80
0.56
1.23
7th "
...
1.00
0.48
2.58
19th
" ...
0.48
0.34
1.26
11th "
...
0.84
0.18
1.61
22nd "
0.26
0.17
0.82
20th "
...
0.48
0.16
1.00
23rd
"
...
0.44
0.21
0.93
21st "
...
0.52
0.22
...
24th
"
...
0.62
0.36
1.75
25th "
...
0.43
0.24
1.30
25th
"
...
1.13
0.26
1.51
26th "
...
0.32
0.19
..
29th
"
....
0.53
0.35
1.54
27th "
...
0.26
0.18
...
30th
"
...
0.52
0.26
1.35
1st November ...
0.28
0.24
1st December ...
0.44
0.18
...
2nd
"
...
0.34
0.24
...
2nd
"
...
0.40
0.20
...
9th
" ...
0.18
0.07
0.46
Average ...
0.48
0.25
1.26
10th
"
...
0.15
0.11
0.56
12th
"
...
0.17
0.16
0.83
15th
"
. . .
0.43
0.31
0.68
Period III.
1926.
1927.
6th December ...
0.82
0.36
1.71
6th January ...
0.40
0.22
1.00
7th
...
0.40
0.22
1.25
10th
"
...
0.92
0.26
1.46
8th
...
0.36
0.18
1.19
11th
"
...
1.10
0.34
2.51
9th
0.72
0.40
2.40
17th
"
...
1.00
0.44
2.40
13th
0.82
0.34
1.97
19th
"
...
1.20
0.48
2.06
16th
0.66
0.22
1.60
24th
"
...
1.32
0.50
2.80
20th
0.40
0.20
1.34
25th
0.72
0.26
1.46
21st
0.84
0.62
1.98
1st February ...
1.08
1.37
4.02
22nd
"
...
0.56
0.14
1.65
7th
"
1.08
0.44
2.20
1927.
8th
"
1.12
0.40
2.43
9th
0.48
0.40
2.69
10th
"
0.72
0.48
2.80
3rd January ...
0.52
0.28
1.66
14th
"
...
1.36
0.47
2.07
4th " ..
.
0.60
0.26
1.67
15th
"
0.86
0.34
1.80
43
6-A.