Document text
MONTHLY BULLETIN
OF THE STATE COLLEGE OFJ WASHINGTON
•«? 1? ^ PULLMAN, WASHINGTON 1? « 1?
vol. 4 FEBRUARY, 1922 Number 9
Water Purification
for the
Country Home
By M. K. SXYDER
Municipal and Sanitary Engineer
ENGINEERING BULLETIN No. 10
Engineering Experiment Station
H. V. CARPENTER, Director
1922
Entered as second-class matter September 5, 1919, at the
postoffice at Pullman, Wash., under Act of Aug. 24, 1912
illlllllllllllliillilllllllllllllllllll
The ENGINEERING EXPERIMENT STATION of the State Col-
lege of Washington was established on the authority of the act passed
by the first Legislature of the State of Washington, March 28th, 1890,
which established a "State Agricultural College and School of Sci-
ence," and instructed its commission " to further the application of
the principles of physical science to industrial pursuits." The spirit
of this act has been followed out for many years by the Engineering
Staff, which has carried on experimental investigations and published
the results in the form of bulletins. The first adoption of a definite
program in Engineering research, with an appropriation for its main-
tenance, was made toy the Board of Regents, June 21st, 1911. This
was followed by later appropriations. In April, 1919, this depart-
ment was officially designated, Engineering Experiment Station.
The scope of the Engineering Experiment Station covers research
in engineering problems of general interest to the citizens of the
State of Washington. The work of the station is made available to
the public through technical reports, popular bulletins, and public
service. The last named includes tests and analyses of coal, tests
and analyses of road materials, testing of commercial steam pipe
coverings, calibration of electrical instruments, testing of strength
of materials, efficiency studies in power plants, testing of hydraulic
machinery, testing of small engines and motors, consultation with re-
gard to theory and design of experimental apparatus, preliminary
advice to inventors, etc.
Requests for copies of the engineering bulletins and inquiries
for information on engineering and industrial problems should be
addressed to Director, The Engineering Experiment Station, State
College of Washington, Pullman, Washington.
The Control of the Engineering Experiment Station is vested in
the Board of Regents of the State College of Washington.
BOARD OF REGENTS
Hon. Louis F. Hart, Governor of the State, Olympia
R. C. McCroskey Garfield
Adam Duncan Dunn, Wapato
Edwin A. Ritz, Walla Walla
A. W. Davis, Spokane
J. H. Hulbert, Mt. Vernon
E. O. Holland, Secretary Ex-Officio, President State College Pullman
ENGINEERING EXPERIMENT STATION STAFF
Director, H. V. Carpenter, B. S., M. S.
Experimental Engineering, Homer J. Dana, B. S., M. S., M. E.
Electrical Applications, Philip S. Biegler, B. S., M. S., E. E.
Electrical Standardizations, Harry F. Lickey, B. S.
Automotive Engineering Aschel C. Abell, B. S.
Steam Engineering, A. R. Nottingham, M. M. E.
Mechanical Design E. B. Parker, B. S.
Engineering Materials, G. Everett Thorton, B. S.
Gas Power, William A. Pearl, B. S.
Steam Power Robert L. Rhoads, M. S.
Mining Engineering, Louis O. Howard, A. B., M. E.
Metallurgical Engineering Chester G. Warfel, M. E.
Economic Geology, Olaf P. Jenkins, A. B., A. M.
Irrigation and Structures Osmar L. Waller, Ph. B., Ph. M.
Municipal Engineering Morris K. Snyder, B S.
Highway Engineering, Howard E. Phelps, B. S., C. E.
Topographical Engineering, Frederic W. Welch, B. S., C. E.
Architectural Engineering Rudolph Weaver, B. S.
Agricultural Engineering, L. J. Smith, B. S.
Physics Brenton L. Steele, B. A., M. A.
Chemical Engineering, . .Clare Chrisman Todd, B. S., Ph. D.
fe^..,— MfV-T .^-B«<fe* -a^U- - ~^g--
Fig. 1, Polution of Ponds and Streams
Introduction
The farmstead, being the source of supply of the food of the
world, deserves to have special attention paid to its needs. Of these
needs, few are greater than the need for pure water. It would seem
that farming regions, which are usually remote from the thickly
settled districts, would find no difficulty in securing such a supply.
But we find that many of our intestinal diseases, such as diarrhoea,
dysentery, typhoid fever, and the like, are more prevalent in the
country than in the city. This can mean but one thing — the farming
community is very careless about its water supply.
The germs of these diseases may be distributed, disseminated
and carried long distances by water or by milk and vegetables which
have been contaminated by water. These diseases are also spread
over restricted areas by flies and other insects which breed in refuse
and filth. It would seem, then, that the vital problems confronting
the farmer are (a) the problem of securing a water supply that is
sufficient in quantity and that is at all times safe and wholesome,
and (b) the closely related problem of the careful and economical
disposal of the wastes in which flies breed and on which they feed.
The importance of pure water for drinking has been repeatedly
demonstrated. Disease is frequently traced to the use of impure
water from wells polluted by cess-pools, barnyard seepage, or othsr
sources of impurities. The water may be clear, ordorless and taste-
less and still contain dangerous disease germs. In such case, only a
chemical and a bacteriological analysis will reveal the danger, and
such an analysis should always be secured if the water is at all doubt-
ful. Such an analysis, costing but a small part of a doctor's bill,
to say nothing of the discomfort to the sick one, will enable the user
to tell whether purification is necessary.
Paszeur Filter
Fig, 1
In other cases, the pollution is evident from the color, taste, or
odor of the water and from these alone it will be known that pro-
cautions are necessary.
Purification of Water
There are two general methods for the treatment of water for
the removal of impurities; (a) mechanical treatment by screens and
filters, and (b) chemical treatment, by the addition of chemicals.
Mechanical Treatment
Filters. Faucet screens and filters are of almost no value in
the purification of water. Comparatively coarse particles of mineral
matter and long slender threads of green or blue algae may be re-
moved from the water by passing it through the set of four or five
fine brass wire screens, such as can be purchased, ready for attach-
ment to the faucet, at the five-and ten-cent counter of any variety
store or from an oily-tongued agent at twenty-five to fifty cents. So
far as real purification is concerned, these accomplish nothing. The
same results can be obtained by straining the water through two or
three thickness of cheesecloth. There is only one type of faucet filter
that accomplishes any real purification. This type consists of an
inner tube of unglazed stoneware or porcelain and an outer metal
casing, tightly attached to the outlet of the supply pipe, to protect
the earthenware filter and to bring all parts of the filter into equal
use.
Its operation is very slow, requiring several minutes to pass a
teakettle full of water. To maintain its efficiency both as to passing
and as to purifying water, it must be boiled out once or twice a week.
Because it operates so slowly, it is an aggravation to anyone wishing
to secure water, and for this reason but few of them are found in use.
Large filters of a similar type are sometimes constructed to
furnish a filtered supply for drinking purposes only. The stoneware
filter is quite large, so that the amount required at one time for
drinking can be had without waiting for the filter. The outside con-
tainer itself may be of a semi-porous character so that the evapora-
tion of the water from its outer surface will keep the water within
the container cool enough for use; the cooling principle is the same
as that involved in the use of the canvas water-bag.
If the supply is taken from a well and requires to be filtered as
described above to insure its wholesomeness, the best treatment is
that suggested in the paragraph on "Safety Distance" in Bulletin No.
9 on "Well and Spring Protection."
The Sand Filter. Where comparatively large quantities of water
are to be filtered, the sand filter is the type of filter used. The
general plans for the construction of such a filter are shown in
Figure 2. (a and b).
The materials used in construction of the filter box or tank
should be either good concrete or else good brick laid in cement
mortar. The inlet and outlet and overflow pipes should be built into
the walls of the filter so that there can be no leakage around them.
The open spaces in the crushed rock or coarse gravel shown in the
bottom of the filter furnishes a collecting basin so that the whole
area of the filter is brought into operation. The sand layer, at the
time of construction, should not be less than about three feet deep.
Depths greater than five feet are more expensive without giving added
safety. The water should be kept at a depth of two feet or more over
the top of the sand, so that the surface of the sand will not be dis-
turbed by any possible currents from the entering water or from
other sources. The sand required for a filter is about the same as
a "good plastering sand." It should be screened through a sieve of
ten or twelve meshes per linear inch (fly screen), to remove all vege-
table matter, coarse particles, clay lumps, etc. The best results are
obtained by using, for the filter sand, a sand that will pass through
a screen having about twenty meshes to the inch and that will not
pass throught a screen having 50 meshes to the inch (screens Nos. 20
and 50); but such screening materially increases the cost. The
Chamber "B" (Fig. 2) is necessary to make it possible to control the
rate of flow of water through the filter. The rising outlet pipe in this
chamber should be a piece of flexible hose with the upper end held at
the proper height by being fastened to the wall of the filter by a cord
or wire.
Operation of the Filter. When the filter is completed, raise the
end of the rubber hose above the level of the inlet pipe; then fill the
filter with water, taking care to disturb the surface of the sand as
l/<zrt]ca/ Section 0/7 B~B
Surface
Sa nd
Crushed /?oc/r or
Grave/
<Z*&:**;:*:
.A-/-. A.-'-.^^'if.-
:' O
4 . -
4 '•'
'X'-
iO*
."•^':
10
little as possible. Now, lower the end of the hose about one and
one-half inches below the level of the inlet; turn on the water in the
inlet pipe and the filter is in operation. The water passing through
the filter for the first two or three days should be allowed to waste,
after which time it may be turned into the cistern or reservoir. The
filter gives best results when operating continuously at a fixed rate.
To make this possible, the reservoir or cistern should be provided
with an overflow.
The rate of operation should be about fifty gallons per square
foot per day. The head "h" (Fig. 2) required to pass this quantity
of water will vary with the sand used and with the length of time
the filter has been in operation. When the filter is new or has just
been cleaned, "h" should not be over two inches; after a month cr
more service it may be twenty inches. Th filter should then be
cleaned.
Cleaning the Filter. Close the inlet pipe and draw off the water
from the filter. With a square pointed shovel or similar instrument,
carefully remove the upper one-half or three-fourths inch of sand.
Then fill the filter with filtered water, if possible, pouring the water
into the filter through the discharge chamber. When the filter is
full, open the inlet pipe, set the end of the discharge pipe just below
the level of the inlet, and the filter is in operation again. If the filter
is filled with raw water, the flow for two or three days must be
wasted, as previously described.
Size Required. If the house is not provided with pressure water,
but all water has to be pumped from the cistern, as used, the dom-
estic use will average from ten to fifteen gallons per person per day.
If the house is provided with pressure water and fitted with bath,
toilet and other conveniences which go with pressure water, the use
will be from thirty to fifty gallons per person per day. Taking all
kinds of stock into consideration, the use will be about six gallons
per head per day in winter and about sixteen gallons per head per
day in summer. Using the average of the above figures and assum-
ing that water must be stored for use for one-half of the year, a
family of five people having twenty head of stock will require per
day as follows:
11
Use
Regular
Storage
Total
Size of Filter Re-
quired at 50 Gal.
per sq. ft. per Day
When pumping
water from cistern as
60 gal
used
60 gal.
120 gal
Stock use . . .
Waste
220
20
220
20
440
40
With Pressure
Painily use . . .
Water :
200
200
600 gal.
400
3 ft. x 4 ft.
22C
220
440
Waste
80
8(
160
1000 gal.
4 ft. x 5 ft.
The waste from leaks in pipes, etc. in pressure water systems
is usually quite large.
Modifications can be made in the above for different quantities
of stock and a different number in the family.
Construction. The filter tank may be constructed of any ma-
terial that is not subject to rapid decay. Occasionally we find one
built of wood painted with asphaltic paint. Often they are built of
brick laid in cement mortar but the best material to use in their con-
struction is concrete. The concrete should be a rich mixture — one
part cement to two parts sand to four parts crushed rock or gravel.
The crushed rock or gravel should contain no stones larger than one
and one-half inches in greatest dimension. Rounded stones screened
from gravel will be found to work better than the sharp angular ones
of crushed rock. The concrete should be well tamped as it is placed
in the forms.
If possible, when constructing the filter tank of concrete, the
excavation should be made just equal to the outside dimensions of
the tank, the side of the excavation being used for the outside forms.
The bottom of the excavation is carefully smoothed to the desired
shape. The forms for the side walls and the division wall are set
first and these walls are put in first. At the same time, the inlet and
outlet and overflow pipes are carefully set in their proper places.
Some concrete should be allowed to crowd out at the bottom of the
wall forms, so that the bottom of the tank, which is next put in place,
will have a good bond to the side walls.
After a few days the forms are removed and the interior of the
tank plastered with a mortar consisting of one part cement to one
12
part sand, the walls being thoroughly wet before the mortar is put on.
Whenever fresh concrete is to be joined to that which is set, the sur-
face of the old concrete should be thoroughly cleaned and wet anl
covered with mortar before the fresh concrete is put in place.
A good concrete slab cover is preferable but a well made wooden
cover will serve very well.
Chemical Treatment
There are a great many different chemicals used in the purifica-
tion of water, but most of them require an expert operator to apply
them so as to get results. Some others are so injurious to health that
they may be used only in carefully determined quantities and by a
skilled chemist. Leaving these two classes out of consideration, we
have only one or two chemicals which are available for use on the
farm.
Hypochlorite Process. For the destruction of all dangerous bac-
teria which may be in the water , nothing equals in efficiency and
convenience ordinary Chloride of Lime. This may be obtained from
almost any grocery store in small cans costing but a few cents and
the amount required is so small as to make the cost almost negligible.
It should be used in the following manner:
One tablespoonful of the Chloride of Lime is dissolved in ten
quarts of water. This quantity is sufficient to treat 1000 gallons of
water, and the operation is carried but by simply pouring the clear
solution into the water to be treated and stirring thoroughly. This
solution is a powerful germicide and its action is very rapid, ten
minutes or so being all the time required to carry out the purification.
One quart of this solution is sufficient to treat effectively a tank con-
taining 100 gallons of water, and one pint of it stirred into a 50-
gallon barrel full of water will destroy any dangerous germs and
make the water safe for drinking purposes.
One is cautioned against using too much of the chemical, not
because it is dangerous at all, but because an undesirable odor or
taste may be imparted to the water when too large amounts are used.
The strength of solution indicated above, used in the manner de-
scribed, will be found perfectly satisfactory. The qualities of the
13
water will be in no wise impaired and no undesirable conditions wi-i
arise from its use. On the other hand, dangerous water may be made
safe and much sickness prevented.
The solution loses its strength if left standing open for any
time but may be kept for several days in a tightly stoppered bottle.
If so kept, it becomes a very handy germicide to use during the har-
vesting and threshing season. The water used about the cookhouse
and for drinking purposes in the field and about the threshing ma-
chine can be made safe and the amount of typhoid fever and other
intestinal trouble made much less.
Lime Process. Lime is sometimes used for purification of water.
About two or three pounds of quicklime is required for 1000 gallons
of water. If the water is very hard, a large amount must be used.
The quicklime is slacked in a pail of water and is then added to the
cistern or reservoir full of water and stirred in thoroughly. The
action of lime is much slower than that of the Chloride of Lime, as
the former requires about 24 hours to sterilize the water. The chief
difficulty in the use of lime is the accumulation of sediment in the
bottom of the reservoir due to the settling of the lime. The bulk of
sediment is many times the bulk of the lime used and frequent clean-
ing is necessary. The hypochlorite treatment is recommended rather
than lime treatment.
ENGINEERING BULLETINS PUBLISHED BY THE STATE COL-
LEGE OP WASHINGTON ENGINEERING EXPERIMENT
STATION.
1. Sewage Disposal for the Country Home.
Septic tanks and underground distribution systems.
By O. L. Waller and M. K. Snyder. Mar. 1914, July 1916.
2. How to Measure Water.
Construction of weirs and tables for same.
By O. L. Waller. Oct. 1915.
3. Water Supply for the Country Home.
Water Sources, pumps, filters, storage tanks and cost data.
By M. K. Snyder.
4. Construction and Maintenance of Earth Roads.
Grades and grading, drainage and dragging.
By L. V. Edwards. April 1916.
5. Cost of equipment and operation of same, with tables of
efficency.
By O. L. Waller. Aug. 1916 (out of print).
6. Fuel Economy in Domestic Heating and Cooking.
Fuel Tables, heating equipment and care of same.
By B. L. Steele. Dec. 1917.
7. Thawing Frozen Water Pipes Electrically. .
Method of Thawing and list of equipment needed.
By H. J. Dana. Oct. 1921.
8. The Use of Ropes and Tackle.
Illustrations of application to diffrent jobs.
By H. J. Dana and W. A. Pearl. Dec. 1921.
9. Well and Spring Protection.
By M. K. Snyder. Jan. 1922.
10. Water Purification for the Country Home.
By M. K. Snyder. Feb. 1922.
11. Farm Water Systems.
By M. K. Snyder and H. J. Dana. (In preparation).
12. Commercial and Economic Efficiency of Commercial Pipe
Coverings.
By H. J. Dana. (In preparation).
15
The
State College of Washington
Founded and Maintained by the National Government and the
State of Washington
College of Agriculture and Experiment Station
Farm Crops, Soils, Animal Husbandry, Dairy Husbandry, Poultry
Husbandry, Horticulture, Landscape Gardening, Forestry, Farm
Management, Plant Pathology, Agricultural Engineering.
College of Mechanic Arts and Engineering
Architecture, Civil Engineering, Electrical Engineering, Hydro-
Electrical Engineering, Mathematics, Mechanical Engineering,
Physics.
College of Sciences and Arts
Chemistry, Chemical Engineering, Botany, Zoology, English,
Economic Science and History, Foreign Languages.
College of Home Economics
College of Veterinary Science
School of Mines and Geology
Geology, Mining, Metallurgy, Metallography.
School of Education
School of Music and Fine Arts
Music, Oral Expression, Dramatic Art, Fine Arts.
School of Pharmacy
The Graduate School
Department of Military Science and Tactics
Department of Physical Education and Athletics
The Summer Session (six weeks)
.Short Courses from one to twelve weeks, beginning early in January,
are offered in Farming, Gas Tractors, Automobiles, Home Eco-
nomics, and Mining.
The Department of Elementary Science offers three-year vocational
courses in agriculture, horticulture, mechanic and industrial arts,
commerce, and domestic economy, from which young men and
women can, if they desire, be admitted to the Freshman class of
the College.
The College Year Begins Monday, September 18, 1922.
Address all inquiries to :
THE REGISTRAR. Pullman. Wash.
Extension Service, under the Smith-Lever Act, is in charge of the
demonstration and correspondence work in Agriculture, Home
Economics, Boys and Girls Club Work, and County Work.
Address: The Director.
The Division of General College Extension gives correspondence
courses, organizes extension classes, supplies lectures and educa-
tional motion picture films.
Address : Director.
MANY DEPARTMENTS PUBLISH SPECIAL BOOKLETS
UNIVERSITY OF CALIFORNIA LIBRARY
14 DAY USE
RETURN TO DESK FROM WHICH BORROWED
T LOAN DEPT.
RENEWALS ONLY— TEL. NO. 642-3405
This book is due on the last date stamped below, or
on the date to which renewed.
MOV Renewed books are subject to immediate recall.
MAP
LD 21-10C
•rvsr** C. I V d L.
rm 1 i_ ȣ'fo j_
u-ul^ 68 ^ i
u
COAN DEP
«
i
3CT 25 1969 1 4
'
Wtf 5 TBS'^PM
*
^
RFC'D LD MAY
4 7^ -\?. AM 1 7
AJAR6 #75
,99
' frtli/l L^u
nlcm .1 -J
(
q
9
GS<>7
D LD
56 -6 PM
;« -2 PM
LD 21A-38m-5,'68
(J401slO)476B
General Library
University of California
Berkeley
THE UNIVERSITY OF CALIFORNIA LIBRARY