Massachusetts. State Board of Health.

Annual report of the State Board of Health of Massachusetts, Volume 27 online

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results — chemical, bacterial and hygienic — obtained by the Law-
rence city filter. A portion of the investigation into the condition
of the Neponset River has been carried out by the force employed
at the laboratories of the station.

Filtration of Sewage.

The sewage applied to the experimental filters is drawn through a
2.5 inch pipe, 4,300 feet long, from the Lawrence Street sewer at a
point just below the main business street of the city and just above
the entrance of wastes from the large mills. This sewer drains the
streets, houses and stores of the most densely populated section of
the city.

When the investigations at the station were begun, the sewage
drawn from this sewer was of a composition and strength quite dif-
ferent from the sewage used at the present time. There are a
number of reasons for this change, the most important being the
use at the present time of day sewage only at the station, and a
large increase in the number of house connections with the sewer.
Low rainfall and a smaller consumption of water per capita also have
an influence.

Table showing Comparison of Average Analyses of Sewage applied to Experi-
mental Filters at Different Periods.

[Parts per 100,000.]





r


Albuminoid AxMoifiA.


i


j


li


Pbkiod.





1


1




1895

WW

1888-1803,


4.05
8.48
2.00


1.00
0.63
O.flT


.28
.26
.80


.72
.37
.87


11.43
8.07
0.64


6.10
8.88
8.84


2,007,000

1,830,000

870,000



Composition of Sewage and Results of Analyses of Sewage

APPLIED to Experimental Filters.

The above table shows that the sewage of 1894 was stronger

than the sewage of the six preceding years, and that during 1895

it was still stronger than in 1894. The quantity of free ammonia



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No. 34.]



FILTRATION OF SEWAGE.



447



and the numbers of bacteria present have both largely increased,
the total albuminoid ammonia is much greater than heretofore, while
the quantity of insoluble albuminoid ammonia is nearly double that
of any previous year. Analyses of samples of sewage collected
directly from the Lawrence Street sewer, at the point where the
pipe from the sewer to the station begins, have been made each
week during the year. These samples have been collected almost
invariably between eight and nine o'clock in the morning, when
the strongest sewage of the day is passing through the sewer. The
results of the monthly averages of these analyses are given in the next
table, and the second table beyond shows the results of the monthly
analyses of the regular station sewage. The greater quantity of free
ammonia and the lower quantity of oxygen consumed in the station
sewage are due to the slow passage of the sewage through the 2.5
inch pipe from the sewer to the station, with the consequent bac-
terial and chemical changes. It will also be noticed that the sewage
taken directly from the Lawrence Street sewer has invariably con-
tained nitrogen in the form of nitrates and nitrites and also free
dissolved oxygen, and that these substances have disappeared when
the sewage reaches the station.

Monthly Averages of Analyses of Sewage from the Lawrence Street Sewer,

[Part* per 100,000.]







a

r


Albcxinoid Ammomia.


1


NlTBOOBX A8 1


1

1^


it


1809.


1


1


i

3

8

e


1





m


Janaary, .


48


3.93


1.19


.63


.66


7.71


.17


.0115


7.75


3,830,000


Febniary, .


40


2.70


1.02


.64


.38


0.10


.15


.0140


6.10


1.277,000


March, . .


46


2.87


1.02


.68


.84


12.56


.25


.0220


6.84


1,828,000


April, . .


46


2.50


1.07


.02


.45


10.66


.26


.0185


8.00


1,687,000


May. . . .


66


2.87


.09


.64


.46


21.78


.25


.0342


5.16


3,836,000


Jane, .


63


8.28


.03


.46


.48


16.02


.00


.0175


5.45


3,712,000


Jnly. . . .


67


8.73


.04


.47


.47


17.67


.14


.0108


5.08


2,410,000


August, .


71


1.78


.78


.80


.34


0.73


.00


.0000


5.95


3,870,000


September,


72


2.10


.04


.47


.47


11.03


.18


.0000


6.78


1,938,000


October, .


60


2.27


.74


.47


.27


10.18


.17


.0350


6.52


1,892,000


November,


61


1.01


.76


.61


.25


7.01


.10


.0000


5.30


2,217,000


December,


63


2.21


.86


.66


.30


7.96


.23


.0146


7.72


8,716,000


Average, .


67


2.64


.03


.64


.43


11.94


.18


.0148


6.54


2,642,750



Digitized by LjOOQ IC



448



STATE BOARD OF HEALTH. [Pub. Doc.



On at least four days in each week a bottle of sewage has been
taken for analysis from a large tank of sewage at the station, and
this sewage is known as the *' regular" sewage.

Monthly Averages of Analyses of Regular Sewage Samples,

[Parts per 100,000.]





II


a

r


Albuminoid AiiMOiriA.


1


1^


It


1809.


1


1

1


1




January


41


8.67


1.21


.30


0.01


0.08


0.81


2.064,000


February,


41


8.71


O.M


.88


0.06


11.40


6.44


1,678,000


March,


44


4.03


0.87


.88


0.40


0.42


6.82


1.010,000


April


46


8.82


0.88


.80


0.68


8.00


6.44


2,118,000


May


68


8.71


0.67


.22


0.86


10.63


3.40


2,288,000


June,


00


4.24


1.06


.26


1.70


18.07


8.60


8,431,000


July


M


4.41


0.80


.28


0.00


14.37


6.10


2,000,000


August,


70


4.81


1.02


.23


0.70


10.08


6.03


3,422,000


September


08


4.68


1.03


.26


0.78


14.67


6.44


8,073.000


October,


64


4.21


0.87


.27


0.00


10.47


6.34


8,037.000


November,


64


8.93


0.76


.28


0.47


0.47


4.10


8,144,000


December,


48


4.10


0.05


.87


0.68


8.88


6.02


6,218,000


Average, ....


66


4.05


1.00


.28


0.72


11.43


6.10


2,907,000



Other Samples of Sewage collected for Analysis.

In addition to the sewages represented by the preceding tables,
it has been the practice to collect other representative samples for
analysis, as follows : —

1. A sample representing an average of all the sewage pumped
on each Tuesday of the year.

2. Samples representing an average of all the sewage applied to
filters Nos. 1, 6 and 9 A.

3. On each Tuesday of the year a sample of the supernatant
liquid, after allowing regular sewage to stand for four hours.

4. On each Tuesday of the year a sample of the supernatant
liquid, after treating the regular sewage of the day with sulphate of
alumina in the proportion of 1,000 pounds per 1,000,000 gallons,
and allowing to stand and settle for four hours.

5. On each Tuesday of the year a sample of the liquid resulting
from straining regular sewage through a layer of coke breeze.



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No. 34.]



FILTRATION OF SEWAGE.



449



Monthly Averages of Analyses of Average Sewage Samples.

[Parts per 100,000.] ,















a

r


Albuvimoid Ammokia.


i


o s




1809.


1


1


1


i


Janoary, .












8.86


.72


.86


.87


7.58


3.08




February, .












4.20


.87


.42


.46


10.66


4.80




March. . .












8.70


.76


.88


.87


8.60


4.07




AprU, . .












8.45


.77


.84


.48


10.07


6.00




May. . . •












4.48


.77


.83


.44


10.61


8.33




Jnoe, .












4.79


.88


.86


.48


12.86


4.17




July. .












4.14


.65


.28


.87


16.37


8.64




August.












8.01


.64


.20


.84


12.71


8.70




September.












5.24


.77


.28


.40


14.80


4.27




October, .












4.00


.70


.28


.42


11.21


2.75




November, .












8.09


.78


.88


.86


0.27


8.03




December, .












4.14


.74


.42


.82


10.71


4.04




Average,


4.16


.74


.88


.40


11.97


4.12





Monthly Averages of Mixed Samples, representing all of the Sewage applied to
Filters Nos, I, 6 and 9 A.

[Parte per 100,000.]



Digitized by LjOOQ IC



450



STATE BOARD OF HEALTH. [Pub. Doc.



Monthly Averages of Analyses of SupemcUant Liquid from Settled Sewage^ for

FiUer No. 13 A.

[Part* per 100,000.]













§
s
s

r


Albuxihoid AMMOKIA.


j


1

1-1

M
O


i

2


tt


1805.


1


i


1

a

1


Bacteria
Cubic Ce


Jannary,










4.26


.fll


.41


.20


0.22


3.86


4.3


2.270.00O


February,










4.81


.64


.48


.16


8.88


4.02


6.0


l,M7,0OO


March, .










4.77


.70


.47


.28


13.74


6.05


2.7


1,464,000


April, .










4.52


.66


.47


.10


13.10


8.70


-


1,017,000


May, .










4.23


.46


.28


.17


12.66


2.50


2.4


1,065,000


June, .










4.82


.46


.29


.17


17.16


2.85


1.0


1.447,000


July, .










4.23


.80


.26


.18


14.64


2.02


4.6


1^14,000


August,










8.01


.36


.18


.18


12.11


2.47


1.8


1,601,000


September, .










4.71


.46


.22


.24


14.07


2.42


3.0


1,436.000


October,










4.08


.46


.28


.18


12.30


3.60


0.0


2,610,000


November, .










4.08


.61


.83


.18


10.68


8.48


6.3


2,471,000


December, .










4.81


.68


.88


.20


7.80


3.08


8.8


3,740.000


Average




4.47


.62


.34


.10


12.27


3.40


3.3


2,018,000



Monthly Averages of Analyses of Supernatant Liquid from Sewage treated with
Sulphate of Alumina, for Filter No. 19.

[ParU per 100,000.]













a

r


Albumimgid Akuonia.


1


5




li


1805.


1


1


1
1




January,










8.77


.86


.26


.10


8.42


2.20


1.0


734,000


February,










3.40


.33


.21


.12


10.16


2.23


1.0


M6,000


March, .










4.68


.60


.86


.14


12.89


4.23


8.0


496,000


April. .










4.20


.80


.27


.12


11.10


2.00


-


1,033,000


May. .










4.02


.28


.10


.00


10.45


1.83


1.6


1,818,000


June, .










4.63


.88


.20


.18


12.69


2.30


1.8


1,252,000


July. .










4.23


.87


.28


.14


14.89


2.30


2.8


1,680,000


August,










4.66


.86


.21


.16


14.21


2.16


1.3


2,222.000


September,










6.17


.42


.26


.17


26.48


2.65


2.6


1.683,000


October,










4.48


.88


.24


.00


12.80


2.70


0.7


1,880,000


November,










3.06


.36


.29


.07


10.44


2.28


2.8


886,000


December,










4.27
4.20


.40


.27


.18


7.32


2.00


1.2


1,185,000


Average




.87


.26


.12


12.67


2.30


1.0


1,147,000



Digitized by LjOOQ IC



No. 34.]



FILTRATION OF SEWAGE.



451



Monthly Averages of Analyses of Sewage strained through Coke, for Filter

No. 14 A.

[P«rU per 100,000.]













1

a

r


ALBUMIKOm AlIMOMIA.


i


1

9

5




li


1805.


1


1


1


ill


JaDoary,


4.21


.48


.88


.15


8.06


3.00


-


1,344.000


Februi/ry, .










4.74


.58


.41


.12


8.84


8.40


0.0


742,000


March, .










5.64


.67


.47


.20


12.84


4.40


4.0


1.150.000


April, .










4.40


.60


.84


.10


11.04


8.18


-


840.000


May. .










4.10


.34


.24


.10


12.00


2.27


2.8


1.040.000


Jaoe, .










4.61


.89


.22


.17


21.50


2.25


1.2


888.000


July. .










4.67


.30


.26


.14


17.80


1.00


8.0


1,100,000


Aagnat,










4.48


.30


.10


.11


14.36


1.83


1.6


098.000


September,










6.50


.42


.28


.10


17.00


2.05


3.3


1.909.000


October,










4.86


.52


.88


.10


18.56


8.10


1.0


1,822.000


November,










4.06


.56


.34


.21


10.45


8.03


0.0


1.888.0C0


December,










4.08


.88


.20


.12


7.62


2.48


2.8


1.664.000


Average




4.82


.40


.80


.18


13.09


2.80


3.3


1,883,000



Summarizing these results, we find that, by allowing the sewage
to settle in barrels for four hours and then drawing a sample for
analysis from a faucet half-way between the top and bottom of the
barrel, this sample shows a removal of 48.0 per cent, of the organic
matter (total albuminoid ammonia) and 31.0 per cent, of the bac-
teria. By this same treatment, together with the addition of sul-
phate of alumina, a removal of 63.0 per cent, of the organic matter
and 61.0 per cent, of the bacteria has been obtained. By straining
sewage through a layer of coke, 54.0 per cent, of the organic mat-
ter and 54.0 per cent, of the bacteria have been removed from the
entire volume of sewage strained.



Digitized by LjOOQ IC



452



STATE BOARD OF HEALTH. [Pub. Doc.



Comparison op the Strength of Station Sewage.

Bringing together for comparison the average results of analyses
of the several series of samples of untreated sewage, we have : —

[Parts per 100,000.]





r


Albuminoid Ammonia.


i
1
S


ll
1


e

2i


180S.


I


1


j


i'


Regular,


4.05


1.00


.28


.72


11.43


5.10


4.08


Average,


4.15


0.74


.83


.41


11.07


4.12


4.61


For Filter No. 1,


4.29


0.74


.88*


.41


11.73


4.78


4.78


For Filter No. 8


4.05


0.68


.80»


.88


10.09


4.00


4.43


For Filter No. A


4.20


0.78


.33*


.40


9.01


3.55


4.71



• Estimated.



Composition or Sewage.

During 1895, series of samples of sewage from Framingham,
Marlborough and the Worcester State Lunatic Hospital have been
taken in continuation of the studies of the strength and composition
of the sewage applied to different filtration areas in the State. All
chemical samples were treated, immediately upon collection, with
mercuric acetate in the proportion of 1 pai-t to 4,000, to kill the
bacteria and prevent decomposition between the time of collection
and of analysis. A separate sample was taken for the immediate
determination of the dissolved oxygen present, and still another set
of samples was taken, from which plantings for the determination
of the number of bacteria present were made. These samples were
all taken during cooler weather in 1895 than in 1894, and, conse-
quently, the percentage of dissolved oxygen present was greater.

It will be noticed that all samples were taken at a point where
the sewage entered a settling basin. The special features in regard
to the places where samples were taken in 1895 were given in the
report for 1894, but, for accurate understanding, are repeated.

Worcester State Lunatic Hospital. — Situated on the outskirts of
the city, and not connected with the city sewers. Practically all the
water entering the sewer passes through a meter on the city service
pipes. The number of inhabitants on the day when the series was



Digitized by LjOOQ IC



No. 34.] FILTRATION OF SEWAGE. 453

taken was 980. The samples were collected, as in 1894, at a man-
hole several hundred feet from the buildings, and just above the
settling tank through which the sewage passes on its way to the
irrigating field. The high temperature of the sewage is due to
the fact that a considerable portion of the water supply is used for
laundry purposes six days in the week. The sewage is very fresh
at £he point of collection of samples ; that is to say, the mixture of
organic pollutions and water has very recently taken place, and,
owing to this fact, the sewage uniformly contains nitrogen in the
form of nitrates and nitrites, and the proportion of free ammonia to
organic nitrogen is very low. In fact, the sewage is so fresh that
. good and representative samples are collected with difficulty, as the
floating matters are not well broken up before reaching the point
of collection. The measurements of the flow of sewage were taken
from the meter readings giving the volume of water used.

Marlborough. — The sewerage system of this city is of the so-
called separate type ; but, as there are no underdrains beneath the
sewers, a considerable volume of ground water enters them. The
length of the outfall sewer, from the last lateral to the point where
it discharges into the settling tank at the filter field, is about four
miles.

The following series of samples was taken October 30, at the
man-hole just as the sewage enters the settling tank. Measure-
ments of the rate of flow were made by noting the length of time
taken to fill one of the compartments of this tank. Free oxygen
was present in the sewage during the entire twenty-four hours.

Framingham, — The sewerage system is arranged with under-
drains beneath the principal sewers to carry off" the ground water.
The series was collected October 30, at the point where the sewage
enters the collecting basin, about one mile from the village. Free
oxygen was present in the sewage during the entire twenty-four
hours.

In regard to the tables given, it may be said that the samples
analyzed were made up of equal portions of sewage taken at the
hours enclosed by brackets. The average analysis given in each
case is a simple average of the determinations given, and is not, of
course, an exact representative analysis of the sewage of the day.

It is proposed during the coming year to take more frequent
samples in each series, and that these samples shall be in some
measure proportional to the rate of flow of the sewage.

Digitized by LjOOQ IC



454



STATE BOARD OF HEALTH. [Pub. Doc.






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Digitized by LjOOQ IC



No. 34.]



FILTRATION OF SEWAGE.



455



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Digitized by LjOOQ IC



No. 34.]



FILTRATION OF SEWAGE.



457



TcLble shotoing Comparison of Relative Amounts of Different Substances in
Represeniative Sewage from the Several Places Aforesaid.

Nitrogen as Albuminoid Ammonia (WdnJdt/n), with Organic Nitrogen (Kjeldahl),

[Parta per 100,000.]





Worcester

Bute
Lunatic
Hospital.


Marl-
borough.


Framing-
ham.


Lawrence
Street
Sewer.


Experiment
Station.


Nitrogen as albaminoid ammonia

(Wanklyn),

Organic nitrogen (Kjeldahl), .

Per cent, which former Is of latter,

Per cent, of dissolved oxygen.


0.65
8.26

17

00


0.60
1.20

80

46


0.43
1.46

80

28


0.68
2.16

26

63


0.61
1.68
88




Nitrogen as Free Ammonia, with Total Nitrogen (Kjeldahl),



Nitrogen as free ammonia,


0.77


1.04


1.67


1.86


2.81


Total nitrogen (Kjeldahl), .


4.10


8.47


3.19


8.80


4.89


Per cent, which former is of latter,


10


66


49


86


64



Oxygen consumed, determined after boiling Two Minutes and Five Minutes.



Oxygen consumed after two mlnates, .


6.26


2.38


2.88


4.24


-


Oxygen consumed after five minates, .


9.30


8.62


6.16


7.06


-


Per cent, which former is of latter,


66


66


66


60


-



Total Nitrogen (Kjeldahl), with Oxygen consumed after Two Minutes.



ToUl nitrogen (Kjeldahl), . . .


4.10


8.47


8.10


8.80


4.89


Oxygen consumed after two minutes, .


6.26


2.38


2.88


4.24


6.22


Per cent, which former is of latter.


78


146


112


89


84



Total Nitrogen (Kjeldahl), with Chlorine,



Total nitrogen (Kjeldahl),

Chlorine,

Per cent, which former is of latter.



4.10
8.93
104



3.47
6.73
61



8.19
7.01
46



8.80
6.79
66



4.39
9.17
47



lotal Nitrogen (Kjeldahl), uHth Fats.



ToUl nitrogen (Kjeldahl),

Fats,

Per cent, which former is of latter.



4.10
6.1
80



8.47
2.7
128



8.19
6.6

68



8.80



4.89



Digitized by LjOOQ IC



458 STATE BOARD OF HEALTH. [Pub. Doc.

This last table shows the relative amounts of the diflTerent sub-
stances in the average sewage of each place. The average analysis
of the Worcester Hospital sewage agrees very closely with the aver-
age analysis of the 1894 series. The number of inhabitants of the
institution and the total flow of sewage for the day are also nearly
identical for both years. With the Marlborough and Framingham
sewages the amounts of these various substances are less in almost
every instance in 1895 than they were in 1894. This difference is
due to the fact that the total daily flow of sewage was greater on the
day on which the series were taken in 1895 than it was in 1894.
That is to say, the sewage, especially at Marlborough, was diluted
by a much larger volume of ground water, owing to recent rains.

The chief points of the analyses to be noticed are that, as in
1894, the amount of organic nitrogen represented by the albuminoid
ammonia is a comparatively small and variable per cent, of that
found by the Kjeldahl method. This percentage is lowest where the
sewage is freshest and the amount of dissolved oxygen highest ;
where the sewage is most stale, that is, where it has undergone the
longest- continued chemical and bacterial action, the percentage is
greatest. The percentage which the nitrogen, as free ammonia,
forms of the total nitrogen, follows the same general rule.



Permanency of Sewage Filters.

The permanency of a sewage filter depends upon the maintenance
of an equality between the amount of organic matter applied to the
filter, and the amount purified and removed in the effluent or escaping
into the air in the form of gas, plus the amount removed from the
surface of the filter. If a limited area for filtration purposes is a
necessity, there is of course more or less accumulation of organic
matters upon the surface of the filter or within the upper few inches
of the filtering material.

If the sewage is fresh when it flows upon the filter, the organic
matter in suspension will not be finely divided and hence will strain
out, remain upon the surface of the filter, and can be removed with-
out removing much if any of the filtering material. This removal
keeps the filter porous, in good condition, and the dry scum removed
decomposes so slowly that it does not create a nuisance. On the
other hand, if the sewage is stale when it flows upon the filtering



Digitized by LjOOQ IC



No. 34.] FILTRATION OF SEWAGE. 459

area, and the sludge or organic matter in suspension is finely divided
"by the comparatively long-continued mechanical, chemical and bac^
terial actions through which it has passed, a much larger percentage
of this organic matter will pass into the interstices of the filtering
material, and, if removed in any way except by being changed into
the inorganic form and passing away in the effluent or escaping into
the air in the form of nitrogen and carbon gases, a considerable por-
tion of the surface layers of the filtering material will have to be
removed also.

During the earlier years of the investigations at this station the
sewage applied to the filters was comparatively weak, but fresh ; and
considerable trouble was experienced, caused by the clogging of the
surface of the filters by the crude organic matters of the sewage ; and



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