Evening star. [volume] (Washington, D.C.) 1854-1972, 1890-07-08
TESTING A NEW SEWERAGE PLAN
The Chemical Precipitation Process
Promises Good Results I'm Worcester.
From the Worcester sry

Prom the Worcester SPY.
trial of the new sewage publication works
on Wednesday afternoon Was entirely satisfac-
tory and gives reason for the confident belief
that the sewage problem. 80 vexatious and for
midable to the city government and people OF
worcester for many years, has az length been
solved.
The apparatus and process have been more
than once described. but we may say hero
briefly that the plant consists mainly OF q Sc
ries OF large open tanks or basins solidly con-
s'ructed OF brick, and having combined sur
lace area OF about an acre. and a building in
winch are mill for grinding the chemicals
ana watts IN which these chemicals after being
ground. are mixed with n small quantity OF
crude sewage. This mixture Is thence dis
charged into the stream which flows from the
sewers into the brick basins. where the chemi-
Gals chiefly lime, combine with some of the im-
purities. forming coagulum, which, as n set
ties. carries with 10 60 the bottom OF the basin
the other impurities, leaving the clarified sew
age almost as clear aud hplpid ~ pure spring
water. Tins clarified sewage L. then allowed
TO now on into the river. where our friends in
the valley below expected 60 ind it wholly
unobjectonahle and the sludge is drawn OF
from below and deposited on land adjacent to
the works. where AZ Will be plowed under and
is expected to cause dctriment TO the health
or comfort OF the nelghborhood. The basins
are so constructed that all NAV be used simul-
tancously, or the flow of sewage may be cut OF
from any one or more Of them for removing
the sludge, for cleansing or repairs. When the
system II IN practical operation one OF the ba-
sins will probably be empty OF in the process OF
emptying. while the Others are in use.
On Wednesday, for the FIRST time the sewage
was turned into the new works. and the first
trial was made in America on large scale for
the process OF chemical precipitation for puri-
lying sewage. The discharge from the sewer
flowed into the basin. dark. foul, noisoms
flood. One tank was filled; the stream was
shut of. and IN half an hour water dipped from
the basin was clear, without odor aud with
only the slightest possible trace OF discolora-
ton. This very gratifying result. after the
sewage had settled for half an hour only in one
tank. justIiies the confident belief that after
passing IN succession through several tanks,
with opportunity for further settlement in
each. the eifiuent will be free from all OBJ
lecnonable matter could be desired This.
however, Is only the first trial of the new pro-
cess. Further experiments will be necessary
20 determine the best combination of cheml-
Gals, and the proper quantity TO make the pro-
cess most efficient with the least expense and
other conditions which will best secure the
efficient aud economical operation of the works.
These experiments will Toe made carefully and
their results used 10 bring the new system into
uniform operation.
The cost has been less than il was at first
feared that II would be. The total appropria-
ton was about si35. 900. of which not all has
yet been expended More than half of this
sum was for the cost OF the outfall sewer from
the main sewer to the purihcation works. The
capacity OF the works II ample Tor the purifica-
ton of 9.OOO,OOO gallons of sewage daily. which
IS more than the present volume of city sewage.
The annual cost of the process Is expected to
be somewhat more than Sz0.O0O. depending in
some measure upon the quantity of chemicals
which may be found necessary