The commonwealth. (Scotland Neck, N.C.) 1896-1929, 1902-11-27
RIVER PURIFICATION
New Facts in Regard to the Sani.
tary Condition of Streams.
Old View That Running Water Puri-
fed Itself Every Twenty Miles Ii
Proved FallaciOus Sluggish
Streams Purify Fastest.

"During recent years there has been
change Of opinion as to the self-puri-
fcation of river waters" says re-
port of the geological survey. "The
most rapid purification is found to
take place in still water, and not in
deep, as formerly held. The issue be-
tween Chicago and ST. Louis, occa~
Stoned by the opening Of the Chiea go
drainage canal, through which the
sewage of Chcagois conducted to the
Mississippi river via Desplaines and
Illinois rivers, is based upon the cOndi-
tiopDin the minds Of the people Of ST.
Louis that there will ariss effects det-
rimental to the water Of the Missis-
sippi river at that city. The whole dis
pute centers, therefore, about the cid
moot question as to how long Il dis
tance is necessary for river to flow in
order to purify itself.
1--WE know from chemical analysis
and physical examination thbt vary
ing degree of purific takes place
in river. In early days this was
thought to be due to aeration, and the
tumbli,lg of water down mountain
sides became the basis for poetic txbi-
1ication Of purity. The experiments
of the Massachusetts state board of
health have shown that aeration has
little or no effect upon the condition
of organic matter in water-that is,
the organic matter is not assisted in
it's oxidation by agitation in the air.
1t was also found that the highest de-
gree of activity III oxidation processes
is to be found in qt1escent or stagnant
waters. 1t then became clear that
self-purification in a sluggish stream
is far more effective than in a swift
current, and that dams and other inl-
pediments have beneficial effect up
on the condition CT water i'll river
channels"
''Promulgation of the facts relating
to the self-purification of waters,"
says Prof. Leighton, who is the au-
thor of the report, ''led to an entire
change in the ideas concerning the dis
tance necessary for stream purifica
ton, and it is now understood that no
hard and fast rules can be set for guild
ance in determining the purifying
power of any water course. A royal
commission, appointed to inquire into
the conditions of EnglaAd's rivers,
reported to the English parliament
In the early seventies, held that no
stream i'll the United Kingdom was
sufficiently long to effect it's own puri
fication. The familiar and oft quoted
principle is that a stream phrifies itself
in 20 miles, but how this dis tance was
determined aid who was responsible
for it is a matter of doubt; certain it
IS that the statement is entirely wrong
in the majority of cases. Pettenkof-
fer, Nering, Stearns and others have
given formulae which are undoubtedly
true for the rivers upon which these
men worked. but which can in no wise
be accepted for rivers in general, and
it remains for the investigator to de
termine by actual experiment the pri
flying power of each stream with which
he has to deal"
The work of examination of the sur
face waters of the United States re-
Gently inaugurated by the geological
survey in cooperation with the various
college laboratories throughout
country, will be useful in the determin-
alton of the self-purifying powers o
many of the interstate rivers. Thes
results will be highly beneficial to the
municipalities and corporations which
| may be looking toward the establish
ment OF sewerage systems. and purifi
cation works.