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

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and this, together with the extremely cold weather and the conse-
quent depth of frost in the filter, clogged the surface of the filter to
such a degree that the applied sewage was disposed of with diffi-
culty, and on February 1 the rate of application was reduced to
80,000 gallons per acre daily and increased to 160,000 gallons per
acre daily April 1. The character of the eflluent deteriorated,
however, during February, but improved rapidly in March and
was fairly satisfactory during the remainder of the year. During
the winter the sewage was applied to a trench 1 foot in depth
and on March 23 this trench was filled and the surface of the filter
levelled. Later in the spring it seemed probable that sub-surface
clogging was taking place in the filter, and the quarter of the surface
to which sewage is applied was dug over to the depth of 18 inches
on May 18. This was followed by greatly improved nitrification.
On October 22 the surface of the filter to which sewage is applied
was spaded over to the depth of 6 inches. The following table gives
the results of the monthly averages of the weekly analyses : —

Monthly Averages of Analyses of Effluent of Filter No. 10,

[Parts per 100,000.]



Sewage applied, 200 gallona six timea a week, January 1 to 81; 100 gallons six times a week, Feb-
ruary 1 to March 31; 200 gallons six times a week, April 1 to July 81 ; 160 gallons six times a week,
August 1 to October 22; 75 gallons three times a week, October 23 to 31; 160 gallons six times a week,
November 1 to December 31. April 11 to 20, experiment interrupted by a freshet. August 81 to Sep-
tember 6, a trap 18 Inches high was attached to outlet pipe. October 12, grass and weeds removed from
that part of surface which Is not flooded, and sand dug over inches deep. That part of the surface to
which sewage Is applied has been raked once each week, except once In January and twice in February.
May 18, that part of surface to which sewage Is applied was spaded over 18 Inches deep; August
20, 8 Inches deep; October 22, 6 inches deep; December 27, 3 Inches deep. During January, 16} Inches
of snow and 3 Inches of loe removed from that part of surface to which sewage Is applied ; during Feb-
ruary, 30| Inches of snow and 6| Inches of Ice removed; during March, 5] Inches of snow removed;
during April, \ Inch of snow removed; during December, 8 Inches of snow and | inch of Ice removed.



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482



STATE BOARD OF HEALTH. [Pub. Doc.



Filters Nos. 12 A, 15 B and 16 B.

Filter No. 12 A contains 60 inches in depth of sand of an effective
size of 0.19 millimeter, and filters Nos. 15 B and 16 B contain 65
inches in depth of gravel stones of an effective size of 5.40 milli-
meters. These three filters were first put in operation in July,
1892, and the effluents of filters Nos. 15 B and 16 B have uniformly
been applied to Filter No. 12 A.

The actual rates of filtration in gallons per acre daily of these
three filters during their period of operation up to Jan. 1, 1896,
have been as follows : —





ISM.


1898.


1894.


1895.


Filter No. 16 B


206,000


406,000


474.000


440,000


Filter No. IflB


206,000


432,000


463,000


406,000


Filter No. 12 A


411,000


T46,000


700.600


641,000


Average rate for the combined area, .


137.000


248,300


283,600


214,000



Since the first part of 1893, filtration in filters Nos. 15 B and 16 B
has been aided by a current of air drawn down through the filters.
It is seen from the table above that Filter No. 12 A has not been
able to take the entire volume of effluent of the gravel-stone filters
during the past three years, and that its quantitative capacity has
gradually decreased. Beginning March 24, 1893, the surface of
Filter No. 12 A was scraped on an average once in five days during
the year, to relieve clogging, and the average depth of sand removed
at each scraping was 0.24 inch. The removed sand was washed and
replaced. From Jan. 1, 1894, to June 19, 1894, the surface of this
filter was scraped whenever necessary, to remove clogging, and the
removed sand was not replaced.

The average interval between scrapings up to June 19 was seven-
teen days, and the average depth scraped was 0.17 of an inch, equiv-
alent to 12 cubic yards of material removed per 1,000,000 gallons
of partially purified sewage filtered. From this date until the end
of 1894 the surface was raked to a depth of 3 inches twice each
week and spaded over 6 inches deep September 6 and October 27,
and 8 inches deep on November 21. The filter was in good con-
dition at the beginning of 1895 and the same method of treatment



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No. 34.] FILTRATION OF SEWAGE. 483

was contiDued, the surface being raked to a depth of 3 inches twice
each week during the year and spaded over to a depth of 6 inches
March 15, May 25, July 17 and August 3. Towards the end of
September the filter began to be badly clogged, and was spaded over
to a depth of 6 inches six times between September 21 and Novem-
ber 1, and to a depth of 8 inches seven times between November 1
and December 12. The quantitative capacity of the filter steadily
decreased however, and on December 7 the surface sand to a
depth of 7 inches was removed, washed and replaced. This sand,
before washing, contained 76.10 parts of nitrogen by weight in
100,000 parts of dry sand, and after washing, 7.90 parts. Follow-
ing this treatment the applied sewage was disposed of more readily.
It seems probable that though the organic matters stored in the sand
are not present in large quantities, they are of a fatty nature not
easily acted upon bacterially ; are, in fact, the organic matters that
have been partially worked over while passing through the gravel
filters and the more easily attacked portion removed. The effluent
of Filter No. 12 A has been of most excellent quality throughout the
year.

Filters Nos. 15 B and 16 B have received sewage during their
period of operation at the rate in gallons per acre daily given in the
preceding table. From the time the aspirators were attached to the
filters until Sept. 1, 1894, a current of air was constantly drawn
down through the filters at the rate of about one gallon in every four
minutes. At this date the method of a(3ration was changed, so that
the filters were aferated only at night for twelve or sixteen hours.
Better results followed this method of aeration, and the volume of
air supplied was sufficient, as shown by examination of the effluents
for dissolved oxygen, it being almost uniformly present. The sur-
faces of these two filters were not disturbed until July, 1893, a year
after they were first put in operation, but since that date they have
been raked and spaded over very often. During 1895 they have
been raked over once each week to a depth of 3 inches and spaded
over 6 or 8 inches deep when the condition of the surface required
it. There has been an accumulation of organic matter in the filters
each year, and to such an extent that, in order to continue them in
service. Filter No. 15 B had to be flushed out twice during 1894 by
applying city water under pressure for six hours to the outlet pipe,
the wash water flowing away over the top of the filter. Filter No.
16 B was given a similar flushing out during 1894, and later the



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484



STATE BOARD OF HEALTH. [Pub. Doc.



filtering material was entirely removed and replaced after washing.
February 1, 1895, the entire filtering material of Filter No. 15 B
was removed, washed and replaced, and after the high water of the
Merrimack River in April, the upper 6 inches of gravel in both
filters was removed and washed, to free it from river silt. The
aspirator of Filter No. 16 B has been allowed to run from nine p.m.
to five A.M. each night during the year, and that of 15B for the
same hours until September 2, since when it has been allowed to
run from nine to eleven p.m. Aeration for two hours has sufficed
to give a good effluent, but there has undoubtedly been a hirger
percentage of organic matter stored in the filter than there would
have been with longer continued aeration each day. In conclusion
it seems reasonable to say that the rate of application of sewage and
the period of aeration should be so defined that flushing out the
filters, or removing and washing the filtering material, would seldom
be necessary, as these operations in themselves create a very large
volume of sewage to be in some manner disposed of.

The quality of the effluents of these filters during 1895 is shown
by the following tables : —

Monthly Averages of Analyses of Effluent of Filter No. 12 A,

[Parts per 100,000.]





Q'lan-
Ap^ilfed.


rKMPRRA- '
TUBE.

Dbo. F.


Length of

Time

Sewage


Appbaramck.


Ammonia.




KITROOKN
AS


1


1
6


















1895.


Gnllons
per Acre

Dalljr
for Six
DHVsina

Week.


f


1

1


Remained

on
Sarfkce.

Hours and
Minutes.


f


i


1


a
1

<


7.75


s


2


e

1


||


JaDaary, .


620,000


42


45


' 2h.81m.


V. Blight.


.19


.0014


.0282


2.57


.0000


.29


1,670


February, .


690,000


41


43


, 3h. -


V. slight.


.24


.1030


.0290


8.05


2.27


.0015


.87


2,866


March,


701,000


44


48


2h. 45m.


V. slight.


.26


.0109


.0288


10.12


2.12


.0002


.87


2,146


April,


402.000


47


50


2h. 19m.


None.


.27


,.0019


.0277 111.07


2.«1


.0000


.36


676


May, . .


804,000


58


56


2h.31m.


V. slight.


.26


.0013


.0282112.2.5


1.32


.0000


.88


006


June,.


835,000


68


68


Ih. 19m.


None.


.27


.0012


.0275 16.27


1 1.46


.0000


.83


474


July, . .


837,000


69


69


2h. 82m.


None.


.22


.0008


.0257i 18.53


' 1.94


.0000


.30


87T


Auifaat,


855,000


71


71


2h. 22m.


None.


.19


t.00l2


.0206 14.43


: 2.60


.0000


.27


128


September,


874,000


67


65


1 2h.36m.


1 None.


.17


.0013


.0237 16.71


1 3.44


.0000


.23


810


October, .


408.000


56


56


3h 22m.


1 None.


.34


.0046


.0249 12.12


2.35


.0003


.26


1,566


November,


254.000


54


54


1 3h. 80m.


None.


.17


.0098


.0340


8.76


2.40


0005


.18


971


December,


411,000


50


53


8h. -


None.


.19


.0010


.0222


8.09


1.81


.0002


.26






Effluent of filters Noa. 15 and 16 applied 24 times a week^ January 1 to July 9; thirty timea a week»
July 10 to Auguai 2; twenty-four times a week, August 3 to September 21; thirty times a week, Sep*
tember 22 to November 7; none applied October 18 to 26; once a week, November 8 to 24; twenty. four
times a week, November 26 to December 31. April 11 to 24, experiment interrupted by freabet. Bnr>
face raked 3 inchea deep twice each week. February 16, 6 Incbea of aand removed; aand replaeed in
Unk March 1. February 18 and August 8, | inch of sand removed. Sand disturbed 6 inchea deep on
following dates: February 16, March 15, May 26, July 17, Auguat 8, September 21, October 6, 10, 12, 18
and 28. Sand disturbed 8 inches deep on the following datea : November 8, 11, 16, 18, 22, 29 and Decern,
her 2. December 7, 7 Inches of sand removed, washed and replaced In tank.



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No. 34.] FILTRATION OF SEWAGE. 485

Monthly Averages of Analyses of Effluent of Filter No. 15 B.



Sewage applied, 2 eallons aeventy two tlmee a week. No sewage npplled, January 4 to 10, January
28 to February 1. April 10 to 20, experiment interrupted by freshet. Filter was aspirated sixteen hours
each night, January 1 to March 2, except frora January 4 to 10, and January 28 to February 1, when
aspirator was run continuously; eight hours a day, March 4 to May 13; fifteen minutes a day, May 14
to June 4; one hour a day, June to 12; eight hours a day, June 13 to August 31; two hours a day,
September 2 to December 31. February 1, all the gravel Uken out of tank, washed and replaced.
March 2, 5 inches of gravel removed from tank. April 20, inches of gravel removed from tank,
washed and replaced. Surface raked 8 inches deep once a week. Surface spaded 12 inches deep Jan.
nary 30. December 14, under-d rains washed out with city pressure.

Monthly Averages of Analyses of Effluent of Filler No, 16 B,



Sewage applied, 2 gallons seventy-two times a week. April 10 to 20, experiment interrupted by
freshet. Filter aspirated eight hours each night. September 2 to 26, aspirator run at one-quarter reg.
ular speed. March 2, 5 inches of gravel removed from tank. April 20, 6 inches of gravel removed from
tank, washed and replaced. December 14, under-drains washed out with city pressure. Surface raked
3 inches deep once a week.

Filter No. 13 A.
This filter contains 60 inches in depth of medium fine sand of an
effective size of 0.19 millimeter, and has received the supernatant
liquid from sewage which has been allowed to settle for four hours.



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486 STATE BOARD OF HEALTH. [Pub. Doc.

The rate of filtration during the greater part of 1895 has been ap-
proximately 160,000 gallons per acre daily. The filter was in good
condition at the beginning of the year and was raked to a depth
of 3 inches twice each week during the year and spaded over to a
depth of 6 inches March 15, July 5, August 24, September 4 and
22, and October 4, 18 and 28. During the first eight months of the
year nitrification was active in the filter although the eflluent con-
tained free ammonia in considerable quantity, but during September
the nitrates of the eflluent rapidly decreased and the filter was
spaded over repeatedly to a depth of 6 inches, as noted above,
but without appreciable eflfect upon the character of the efiiuent.
On October 28 the gravel under-drains of the filter were flushed out
with city water and a large amount of iron which had been deposited
upon the gravel was in this way removed. Following this treat-
ment the quality of the eflluent rapidly improved, and during
November and December the nitrates were the highest and the
ammonias the lowest of the year. It seems probable that during
September and October there was good nitrification within the filter
but that the nitrates of the effluent were reduced to free ammonia
while passing through the under-drains of the filter. The following
table gives the monthly averages of the weekly analyses : —

Monthly Averages of Analyses of Effluent of Filter No. 13 A.

[Parte per 100,000.]



Settled sewage applied, 4 gallons twelve times a week. No sewage applied, October 17 to Novem-
ber 1. April 10 to 22, experiment interrupted by freshet. Surface raked 3 inches deep twice each week*
Surface dug over 6 inches deep on the following dates : March 16, July 5, August 24, September 4, 22,
October 4, 12, 18 and 28. October 28, under-drains washed out with city pressure.



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No. 34.] FILTRATION OF SEWAGE. 487



Filter No. 14 A.

This filter contains 60 inches in depth of medium fine sand of an
effective size of 0.19 millimeter, and has received since June 1,
1894, sewage which has been strained through a shallow layer of
coke. This partially purified sewage has been applied to the filter
at an average rate, excluding periods of rest, of 320,000 gallons per
acre daily during the year. The surface of the filter has been raked
to a depth of 3 inches twice each week during the year and spaded
over to a depth of 6 inches, March 15, August 24 and October 6.
The quality of the effluent has been satisfactory throughout the year
and has invariably contained high nitrates. The filter was in ex-
cellent condition at the end of the year. The following table gives
the monthly summary of the analyses made during the year : —

Monthly Averages of Analyses of Effluent of Filter No. 14 A,

[Parts per 100,000.]



Four gallons of sewage, strained through coke, applied twenty-foar times a week. No sewage
applied October 21 to November 1. April 10 to 20, experiment interrupted by freshet. Surface raked 3
Inches deep twice each week. Surface dug over 6 inches deep on the following dates : March 15, Au*
gust 24, October 4, 21 and 28.



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488



STATE BOARD OF HEALTH. [Pub. Doc.



Filter No. 19.

This filter contains 60 inches in depth of medium fine sand of an
effective size of 0.19 millimeter, and has received the supernatant
liquid from sewage which has been allowed to settle four hours after
treatment with sulphate of alumina at the rate of 1,000 pounds per
1,000,000 gallons. The filter has received this supernatant liquid
since Jan. 20, 1893, and the rate of application during 1895 has
been, excluding periods of rest, 200,000 gallons per acre daily.
Nitrification has been very active in the filter during the entire
year, as shown by the high nitrates of the eflluent. The albumi-
noid ammonia of the effluent was comparatively low during the
year, and the comparatively high free ammonia was not caused by
any clogging of the filter but was the natural consequence of the
extremely high free ammonia of the applied sewage. The filter
was raked 3 inches deep each week and spaded over 6 inches deep
October 28.

Monthly Averages of Analyses of Effluent of Filter No. 19 A,

[Pan« per 100,000.]





Qaan-

Applled.

Oalloni
per Acre
Daily
for Six
Days in a
Week.


Tkmprra-

TURK.

Deo. F.


Length of

Time

Sewage

Remained

on
Surface.

Hours and
Minutes.


Appearamcb.


Ammonia.


i
i

6


NlTBOOBM
A8


o


1






o


1

i

.4040


2
o

c

a

o

<
.0288


s


s


.


1890;


i
1


c

s

1


P


January, .


200,000


47


40


38m.


V. slight.


.13


7.24


2.19


.1160


.s«


8,770


February, .


200,000


46


38


6h. 27m.


Slight.


.16


.7500


.0607


0.14


1.76


.0967


.43


8,670


March,


200,000


47


42


Ih.llm.


V. alight.


.15


.4325


.0265


7.66


2.09


.0850


.39


1,62S


April,


200,000


61


47


35m.


V. Blight.


.15


.4750


.0380


11.90


2.90


.0425


.36


1,820


May. . .


200,000


62


60


22m.


None.


.14


.5000


.0295


11.04


2.93


.0413


.30


422


June, .


208,000


72


67


16m.


V. slight.


.17


.0160


.0525


16.55j


4.42


.0083


.34


117


July, . .


103,000


71


67


13m.


None.


.16


.5175


.0415


15.08|


8.94


.0004


.35


664


Auguat, .


10fl,000


73


70


14m.


V. slight.


.14


.1847


.0260


15.26

1


3.52


.0001


.29


460


September,


200,000


60


63


16m.


NODO.


.13


.1474


.0254


13.92


3.68


.0001


.28


126


October, .


170,000


66


67


13m.


None.


.14


.3550


.0260


12.29


3.74


.0000


.26


09


November,


196,000 '


54


50


16m.


None.


.12


.1720


.0313


8.30


3.39


.0167


.27


92


December,


200,000


45


47


19m.


None.


.11


.««


.0353


8.82

1


3.21


.0017


.24


819



Chemically precipitated sewage applied, 5 gallona twelve times each week. No Mwage Applied
October 28 to November 1. April 10 to 20, experiment interrupted by freshet. Surface raked 8 Inches
deep twice eAch week. October 28, surface dug over 6 Inches deep.



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No. 34.] FILTRATION OF SEWAGE. 489

Filter JSTo. 21 A.
This filter was started March 19, 1894. A portion of the filter-
ing material was removed during 1894, but on April 1, 1895, the
filter was restored to its original depth of 60 inches of fine sifted
gravel of an eflfective size of 1.60 millimeters. Since July 7, 1894,
it has had a current of air drawn downward through it, at the rate
of about one gallon in four minutes, for ten or twelve hours each
night. During 1895 this filter has received sewage during its period
of actual operation at the rate of 360,000 gallons per acre daily, ex-
cept during June and July, when the rate of application was 499,000
and 427,000 gallons per acre daily, respectively. The filter became
badly clogged during February and was allowed to rest from Feb-
ruary 18 to April 1, with continual aeration. This treatment im-
proved the condition of the filter and restored nitrification. In
August clogging again occurred and the filter was allowed to rest,
with continuous aeration from ^Vugust 7 to 21 inclusive. During
the remainder of the year the filter was in good condition. The
following table gives the results of the monthly averages of the
weekly analyses : —

Monthly Averages of Analyses of Effluent of Filter No 21 A.

[Parts per 100,000.]



Sewage applied, 2 gallona twelve times a day at intcrvala of one-half hour, six days in a week,
January 1 to August 20; 1^ gallons twelve times a day from August 21 to December 31. No sewage
applied and aspiration continuous, January 5 to 10, January 28 to February 3, February 18 to March 31,
May 18 to 31, August 7 to 20. April 10 to 21, experiment interrupted by freshet. Filter aspirated sixteen
hours each night. Surface raked 3 inches deep daily January 1 to March 31, and once a week during the
remainder of the year. April 1, filter filled to its original depth with washed gravel. April 20, 6 inches
of gravel removed, washed and replaced in tank. January 30, surface dug over 12 Inches deep. Surface
scraped on January 4 and April 1.



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490 STATE BOAKD OF HEALTH. [Pub. Doc.



Filtei* No. 22 A.

This filter contained originally 60 inches of fine coke breeze above
the usual under-drains. The rate of filtration during 1895 has been
360,000 gallons per acre daily. On account of clogging during
February the filter was allowed to rest from February 18 to April 1.
The surface of the filter was raked to a depth of 3 inches daily until
the period of rest and to the same depth twice each week during the
remainder of the year. Up to Nov. 14, 1894, 3.5 inches of the sur-
face coke had been removed, equivalent to 8.6 cubic yards per
1,000,000 gallons of sewage filtered. During 1895 6.1 inches of
coke were removed up to November 14, equivalent to 15 cubic
yards per 1,000,000 gallons of sewage filtered. With the exception
of the months of January and February nitrification in the filter was
active throughout the year. The table of monthly averages of the
weekly analyses is presented below : —

Monthly Averages of Analyses of Effluent of Filter No. 22 A.

[Parts per 100,000.]



Sewage applied, 6 gallons eighteen times a week. No sewage applied February 18 to March 31 •
April 10 to 21, experiment Interrupted by freshet. Surface raked 3 Inches deep daily, January 1 to 31,
and once a week during the remainder of the year. February 1, 8 inches of coke removed, and 3 Inches
of clean coke put on filter. February 18, ^ inch of coke removed from filter; November 15, 3.1 inches
removed.



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No. 34.] FILTRATION OF SEWAGE. 491

. Fillers ^os. 51 and 52.

Each of these filters is one three-thousandth of an acre in area.
Filter No. 51 contains 60 inches in depth of gravel of an effective
size of 5.30 millimeters above the usual under-drains, and Filter No.
52 contains 60 inches in depth of coke breeze, from which the finer
particles have been removed, above the usual under-drains. The
outlets of these two filters have been trapped and they have been
aerated by means of a fan blower driven by electric power, as pre-
viously described. Beginning February 1, each of these filters
received sewage at the rate of 500,000 gallons per acre daily, applied
in six doses between 6 a.m. and noon. This rate of filtration and
method of application continued until May 2, when the method of
application was changed so that twice this volume of sewage was
applied in twelve doses between 7 a.m. and 11 p.m., giving a rate
of 1,000,000 gallons per acre daily. This continued until June 21.
From June 21 to June 25 inclusive the filters were allowed to rest,
and on June 26 they were started again, but the rate of application
of sewage was reduced to 500,000 gallons per acre daily, applied in
six doses between 7 a.m. and 10 p.m. This continued until June
29, when the same quantity of sewage was applied in twelve doses
between 7 a.m. and 11.30 p.m. During these first five months of
operation of the filters nitrification did not become well established,
and although there was a considerable reduction of the free and
albuminoid ammonia of the sewage in passing through the filters, it
was largely on account of retention and storage in the filters. From



Online LibraryMassachusetts. State Board of HealthAnnual report of the State Board of Health of Massachusetts, Volume 27 → online text (page 47 of 73)