Grand Forks herald. [volume] (Grand Forks, N.D.) 1916-1955, 1921-06-15
WEDNESDAY, EVENING, JUNE il, 1921.
r P-URIFICATIoN.

ggiausa In circular issued by the United states pubic
ppskNrdhealth service the following description Is given OF the
sAvtnethods used by the department for the publication Of
SF6fhss water used for drinking and other domestic purposes
ssFs13t the model hospital village and reservation at Perry
ssssa.1adlle, Maryland:
~ ~ THE raw water, which is pumped from the sus-
sAslpehana river through 3o-inch mains to settling tanks,
Rye subject to rapid changes in turbidity ranging from IL.
- n 100 parts per million: and the amount Of aluminium
= = yulphate to Be added as a coagulant and precipitant must
pe varied to suit. Samples of the water entering the
sN lnains are taken every two hours: and the amount of
sGrfoagulant to be added is determined by the chart based
stIn i the amount OF water and its turbid:ty; Tor instance os
Isl grain Of the alum is added for 10 quarts per million OF
y. atnrbidity. This amount, however, is also governed by
Lathe alkalinity. which may vary greatly during the day;
sE.when it drops below IA parts per million, soda ash is
padded
- Two hours are allowed for settlement in the tanks,
NG1}aiter which the water flows by gravity through mechan-
FGrcal rapid sand filters, passing through three feet Of sand
Grand eight inches of stone and gravel at the rate Of two
HNnyd'nches in SIS seconds. Later. the water is treated with
sNTiiquid chlorine, the amount depending on meteorological
IN Dissemination OF the raw and the chlorinated water. This
G. treatment reduces the bacteria from an average of $3.50
MHBstmaximum 7,S6o) per cubic centimeter to less than one.
l = The condition of the water at Perryville is AFFECT.
Cred by the geological formation of the country, by the
conflict OF the tide and the river current, and by
#@onhe strong winds which often cause terrific wind action
s $50 the low flats. all OF which necessitate very effective
sNs1treatment-"
d It may interest Grand Forks people to be reminded
that this is exactly the method used in this city for the
/ treatment of water taken from the Red river Tor dornes-,
isl tic use here. The water in its raw state is always tur-
bid and always carries a large load of bacteria. The
FaH "a OAuAs 10 ISAuoVSu Ill LII SetLiuS UdSlu Oy n use y !
alum, and the bacteria are removed in part by filtration
through sand and in part by the use of chlorine. The
result is a clear water containing very few bacteria of
any kind. and in most cases none at all Of the disease
5A producing bacteria. #
The Grand Forks water is further treated for the
III rePoval of q part of its natural hardness. A part of the
sE~krreatment at Perryville seems to be intended for this 'pur-
pose, though from the description given it does not a-
;EEpear that tie treatment is intended As d distinctiyely
szsoftening treatment. The result OF the Grand Forks
3 Treatment is to produce a water that 10 perfectly clear
and safe from every standpoint. and that is very mate
rally softer than the water in its natural state.
tsA One rather interesting TACT not generally known re-,
sssHlates to the difference between the water in the two
syNrtvers. Fargo takes its water from the Red river, ana
.sA11rand Forks from the Red Lake river. Each city has Its
IS qualification and softening plant, and the treatment is
III Hgenerally similar. But when experiments were made
is sfor the purpose Of determining the proper softening
j Treatment at Grand Forks it was found that the materials
Is used at Fargo for this purpose, and which give satisrac-
III tory results there, would not answer at Grand Forks at
t# #all. The water in each case is hard. but the hardness
H8s due to the presence of different chemical elements, or
#of the same elements in different combinations. Such,
tS differences are common, and sanitary engineers have
IA found that the treatment which is satisfactory in one
i& place may be worthless in another. The fact, therefore,
~ that some other city uses a different method of treating
III water with success is not evidence. that that system ought
l9% TO be adopted. in some other city.