The record-union., 1897-11-06

when the partial oxidation OF organic
matter in flowing water is conceded.
there still remains good ground for OBJ
jecting to this means of disposal.
The first Rivers Pollution Commits
sion'' of England was appointed in
1865 and in its reports emphasized the
fact that publication of flowing water
occurs only in exceptional cases, ana
that sewage cannot be discharged into
any stream or its tributaries without
menace to the health of those using its
waters.
AS the practice of discharging waste
from industrial establishments or
all kinds, as well as crude sewage, into
rivers had become very general in
England, this conclusion was not ac-
cepted without opposition, an oppo-
sition which undoubtedly came large
~ from those who did not wish to be
burdened with the additional expense
that would be put upon them if they
were denied the privilege Of dumping
their refuse into the rivers.
The appointment Of q second COM
mission became necessary, which says,
in one of it's reports: "a very large pro-
portion Of the running waters Of Great
GUS Ito health) or are rapidly becom-
ing So" when the sewage Of towns
or other polluting organic matter is
discharged into running water the sus-
pended matters may be more Or less
perfectly removed by subsistence and
filtration, but the foul organic matters
in solution are very persistent" There
is no river in the United Kingdom long
enough to secure the oxidation and de-
struction of any sewage which may be
discharged into it even at its source. .
The conviction that water, once
fouled, could not be purified by any
method led at least one prominent san
itarian to the conclusion some
years ago that water for domestic use
should not be drawn from rivers at all,
for it seemed hopeless to him to cut
off all sources Of possible contamina-
ton even though crude sewage were
carefully excluded.
BY chemical treatment, often advo-
Gated, and as represented by numerous
processes, it is possible to free the
sewage of portion of it's organic mat
ter. The amount thus removed in act
ual practice rarely reaches one-half:
it is generally only from one fourth 10
one-third. The processes employed are
varied both as regards the chemicals
employed and the method Of handling
the sewage. Sulphate Of iron or sui
phate Of aluminium, together with lime,
are the substances most frequently em-
ployed to produce chemical precipita-
tion. The settling tanks are general
ly arranged either for intermittent on
constant service. In the latter case,
now generally preferred, they are mar
row-usually about thirty feet wide and
long, sometimes 800 to LOCO feet. The
sludge removed from those used for the
treatment of London sewage, after con-
centration in secondary tanks, con-
tainS 90 per cent. of moisture.
No practical chemical treatment has
yet been discovered which does not
leave considerable suspended organic
matter in the effiuent, and about all
that can be said in it's favor is that
it effects a reduction of the amount of
such matter and very often prevents
fouling of stream to that degree
| which renders it apparent to the senses.
There seems to be no justification for
turning the effluent from chemical
precipitation works into q stream
which is to be drawn upon as a source
| of water supply
Chemical treatment produces sedi-
ment or sludge of SO little manurial
value that it is difficult to dispose of
the same even in England, where the
value of manure is fully appreciated.
There are, however, cases where this
treatment is justifiable. It's advocates
some years ago secured its adoption by
London, but the system as applied to
that metropolis has not escaped unfa-
forable criticism. The sludge formed
in tho London settling tanks is carried
fifty miles to sea in specially construct
ed barges The effluent flows into the
| Thames.
Once the conclusion was reached that
| neither by dilution with water nor by
chemical treatment could sewage be
| made harmless, special attention was
devoted to experiments with filters and
the work was so thoroughly done that
the problem of their successful use, not
alone IN the matter of sewage purifi-
cati3n, but also in connection with
water supply for domestic purposes. has
been solved These experiments as
conducted in our country under the i'm
mediate personal supervision of H.
F. Mills of the Massachusetts State
Board of Health, has attracted the at
tention of physicians and sanitarians
in all parts of the world, and the con-
clusions reached are being verified
wherever properly established fltra-
tion systems are made a part of sew
age disposal works.
Without entering into detail it may
briefly be stated that in the upper lay
, ers of 2 mature filter and ii does not
seem to make much difference what the
nature of the material composing the
filter iS-the organic substances in sew
age, all carbonaceous and nitrogenous
substances which are subject to pu-
trefacation and decay. are changed into
harmless compounds This change is
largely due to chemical action facilf-
tated by micro-organisms that have,
not inaptly, been called friendly mi
! crobes.''
The action of new filter does not
become fully established until its upper
layers are thoroughly colonize~d with
these micro organisms Such coloniza-
ton, however, takes place naturally
and easily as a direct result of the
application of sewage to a filter. Fill
tration not only reduces the carbon
aceous ard nitrogenous substances. but
OF the 5o0.0 900 to 5000 600 bacteria per
cubic centimeter in the sewage, very
few are found in the effiuent. or better
stated. the few found in the effiuent
are principally harmless varieties.
Furthermore, 1t was found that filters
n.y. r.,afi fix.esff