The Worcester spy. [volume] (Worcester, Mass.) 1898-1904, 1901-12-17

~ rises TO several scores OF nlllllOnS.
The cost of maintaining the Purifica-
tion Works for the year has been $44,
1922 amounting to $036 per capita.
The amount of sewage treated has
been reduced by the use of the new
system of intercepting sewers so that
the cost per million gallons has in
creased somewhat over that Of pre-
ViOus years 1t should be stated that
necessary repairs and improvements
to plant have been prevented by lack
of funds, which fact will make larger
appropriate for 1902 very necessary.
The average daily flow of sewage
treated has amounted to 9.76 million
gallons, of which about onethird has
been filtered
During July and August. the two
months when the river is most often
sive, the publication amounted to 73.43
per cent removal of albumenOid am
mOnia. During this time, as through
the most of the year, the floating or
suspended organic matter was practi-
cally entirely removed
The work accomplished by the puri-
fiCation plant has been far more salts
factory than during any previous year
and it would seem that if necessary
enlargement of plant could be made,
the problem of sewage disposal would
be solved satisfactorily.
The sewage not filtered has been
treated with chemicals before being
discharged into the river. The method
of treatment has not differed materially
from that followed in previous years.
The increase in the amount of lime
used per million gallons of sewage
treated is explained partly by the very
large amount of sulphuric acid con-
tanned in the sewage and partly by the
e
The net cost of the chemical treat
ment has been 500, 079 %, which makes
the cost per million gallons treated
$6.41. To this should be added the cost
per million gallons sewage treated for
disposing of the sludge, S. So making a
total Of $12 80. The above cost of press
ing the sludge includes the Expense Of
pressing 1t from the settled sewage as
well as that chemically treated, but is
calculated on the latter only.
All sludge produced during the year
has been pressed and the cake hauled
by the narrow-gauge trolley road to
the same dump used last year
The total volume of sludge pumped
from the settling basins to the storage
tanks was 26,957,000 gallons. 1t was al
lowed to remain here as long as pos
Sible and the clear supernatent liquor
W
presses. This amounted to 2,037 900
gallons or IL per cent of the total
The cost of pressing the sludge per
million gallons of sewage treated has
been reduced over that of last year by
1928 calculated on the entire flow of
sewage through the basins.
The filters have received an average
of 100000 gallons Of sewage or chemical
etfluent per acre per day for every day
during the year. This amount has
been purified by the filters to the ex-
tent of about rs per cent of it's organic
matter and including the publication
by sedimentation and chemical preci-
pitation, about IS per cent of the or
ganic matter has been removed.
OF the various methods of treating
sewage which have been tried during
the year. chemical precipitation fol-
lowed by filtration gives by far the
most satisfactory results, if cost is not
taken into account.
The surface of the filters was
ploughed, narrowed or raked once each
month from April to October inclusive
During the latter month 492 cubic
yards of material containing a large
amount of organic matter were re
moved from the filters, averaging "a
cubic yards per acre.
The cost of maintaining the filters
has amounted to $528201, making the
cost of filtering one million gallons
$4.54, reduction of 81 so per million
gallons over last year.
The septic treatment, which might
appropriately be called the municipal
cesspool method, has been continued in
use since May. 1900 and has given in
teresting results. The value attached
to this method of treatment appears to
be chiefly confined to the disposal Of
the suspended organic matter in sew
age. As this is the most troublesome
part of the pOlluting matter, any
method by which it can be disposed Of
Is worthy of careful consideration. A
considerable portion of the suspended
organic matter has been taken out of
the sewage. The flow through the
tank amounted to about 300 900 gallons
per day for six days in the week until
September, 1901, when the flow was
increased to about 100000 gallons per
day. The increase of the flow through
the tank did not appear to make any
material difference in the amount of
organic matter removed from the wat
err The capacity of the tank was $50
600 gallons, about 80 900 of which might
be considered as taken up with the ac-
emulation of solid matter in the bot
tom.
The disagreeable odors from this ba-
sin have continued as in the past, but
are not. on account of the small area.
as Objectionable as the odors arising
from the filter beds. on to which the
efTiuent is turned The odor from these
beds is especially noticeable when the
beds are covered with water. but dur
ing the remainder of the day the sur
face is so moist that the odOr does not
disappear. 1t would seem that this diff
ficultv was one of the most serious in
connection with the use of the septic
tank in any community in which there
are dwellings or through which high
ways run adjacent to the filter beds.
The condition of the Blackstone
River has been studied as in former
years and it is a satisfaction to be able
to report a marked improvement in the
chemical composition of its waters al
though the bed and banks Of the
stream are so foul that the improve
ment has failed to be detected by the
people living in the vicinity. A special
advantage has been gained this year
with the aid of the intercepting system
of sewers and the filter beds. making
ii possible to prevent the increase Of
pollution during the summer months
over that of the rest of the year. Until
last year the pollution of the river was
annually greater during the summer
months. resulting largely from the re-
duction in the volume of water flowing
during that period. 1t is a pleasure to
acknowledge the kindly interest in the
work of the department shown at all
times by the committee on sewers. The
work of the engineering department
has been maintained at it's usual high
efficiency. At this occasion 1t can not
be out of place to credit the assistants
in charge of the various branches Of
the work of this department with the
interest and ability which has marked
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