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PUBLIC HEALTH REPORTS
VOL. 34 DECEMBER 12, 1919 No. 50
ULTRA-VIOLET RAYS IN WATER PURIFICATION.
Some l Abstracts from the Literature on the Sterilization of Water by the Use of
Ultra- Violet Rays.
The Public Health Service has received a number of requests
regarding the sterilization of water by means of ultra-violet rays.
For the information of persons interested in this subject, abstracts of
certain articles on this method of water purification are given below:
Ultra-violet rays finish treatment of Henderson (Ky.) water supply.
Smith, A. T., Engineering News-Record, vol. 79, pp. 1021-1022,
191 7. — The population of Henderson is 17,000; the average consump-
tion of water is about 2.5 million gallons per day. Sedimentation,
mechanical filtration, and ultra-violet ray sterilization are used to
treat water from the Ohio River. A new form of sterilizer is used,
which consists of 3 parallel 5-unit legs. Estimated current con-
sumption is 92.5 kilowatt hours per 1,000,000 gallons. Good bacte-
rial results are obtained.
Ultra-violet ray sterilization of water. Parkinson, N. F., Annual
Report of the Provincial Board of Health, Ontario, Canada, vol. 33,
pp. 156-216, 1914. — The questions of efficiency and cost are consid-
ered. The dependency of the germicidal efficiency of ultra-violet
rays upon their wave length is given detailed consideration. The
process is affected by the character and the turbidity of the water
treated. The construction and operation of two types of mercury
vapor lamps are fully described. Diagrams of various installations
are given. Graphs show the effect of turbidities up to 50 parts per
million, the color being 21. In the small apparatus, water with a
turbidity of 50 parts per million was treated, with a consequent re-
duction of 97.4 per cent in the 37.5° C. bacterial count and 95.2 per
cent in the colon count. In the large apparatus, water with turbidity
of 30 parts per million was reduced in bacterial count by 94.9 per
cent, 91.3 per cent, and 99.46 per cent in the 18-22° C. count, 37.5°
C. count, and colon fermentation, respectively. Slight irregularities
in the condition of raw water supplies can be handled directly
without preliminary filtration. A continuously good effluent requires
a constant voltage and that the lamp be in good condition. Ultra-
1 From ''Chemical Abstracts."
14997r-19 1 (2831)
December 12, 1019. 2832
violet ray treatment of water can be made satisfactory and reliable.
Overdosing gives no detrimental effects other than increased cost.
Cost data and several pages of bacteriological data obtained under
varied operating conditions are given.
Ultra-violet rays; their advantages and disadvantages in the purifica-
tion of drinking water. Spencer, R. R., J. Am. Water Works Assn.,
vol. 4, pp. 172-182, 1917. — A very complete discussion and history
regarding ultra-violet rays is given, and results obtained at the
laboratory of the Sanitary District of the Great Lakes are shown to be
exceedingly good. The use of this method of water purification is
recent and is considered especially good for circulating systems and
relatively small installations. For municipal supplies its expense is
probably prohibitive. An overdosage is impossible, nor is the water
changed in any way chemically. Turbidity in the water and accu-
mulations on the lamps greatly impair the efficiency of the process.
The use of ultra-violet rays in sterilizing water. Am. City, vol. 17,
pp. 239-241, 1917. — Five lamps per million gallons of water allow a
large factor of safety. At Henderson, Ky., with current at about
$0.01 per kilowatt hour, and 15 lamps in use, the cost is $0.88 per
million gallons.
Ultra-violet ray sterilization of water. Dallyn, F. A., and Parkin-
son, N. F., Annual Report of the Provincial Board of Health, Ontario,
Canada, 1914; Can. Engr., vol. 29, pp. 686-692, 1915.— Ultra-violet
rays should preferably be applied to water free from turbidity or
filtered. Experiments are detailed on sewage-infected tap water.
With turbidity 5 to 20 parts per million, bacterial removal was over
97 per cent; with turbidity 20-50 p. p. m. bacterial removal was from
94 to 97 per cent. The lamps used were of 1 10 and 500 volts. Dallyn
concludes that ultra-violet, rays afford protection against irregularities
of filters, with freedom from taste or odor in case of overdose.
The lactericidal action of ultra-violet rays. De Voogt, J. G., Delft.
Z. Hyg., vol. 81, pp. 62-68, 1916.— The following conclusions of
Henri and Cernovodeanu were confirmed: The bactericidal action
of ultra-violet rays on drinking water is proportional to the depthof
the unit of water exposed. It is uninfluenced by the temperature
(0°-55°) and oxygen content of the water. The formation of H 2 3 is
not necessary to produce sterilization. Different bacteria require
different amounts of light. The most active part of the rays lies
at about 280 ^m- 1
Development of ultra-violet water disinfection. Anon., Eng. News,
vol. 74, pp. 634-636, 1915.— The 320 plants i nstalled or approaching
i Do Voogt has not quoted correctly the French authors, Cernovodeanu and Henri (Comptes rendns Ac.
d. So., vol. 150, p. 54). The original of these French authors reads: "Par consequent, les rayons ultra-
violets , de beaueoup les pins bactericides, sont ceux qui ont une longueur d'onde an-dessovs de 2,800 unitiSs
Angstrom."
That is, according to these authors the rays which are most active as bactericides are these -which have
wave lengths of under 280 ju/i.
3 December 12, 1010.
completion in the United States comprise 20 for swimming pools.
The cost is about $750 per 1,000 gallons per hour capacity for machines
of 200 to 3,000 gallons per hour and $900 for those of 60 to 120 gallons
per hour capacity. Direct current is used at 1 10 to 500 volts. For
swimming tanks a pressure filter is used, followed by sterilization.
Ultra-violet rays and their application for sterilization of water.
Von Recklinghausen, M., J. Frank. Inst., vol. 178, pp. 681-704, 1914;
J. Am. Water Works Assn., vol. 1, pp. 565-588; Chemical Abstracts,
vol. 8, p. 3830.
Germ-destroying power of ultra-violet rays applied to sterilization of
water and disinfection of trade packages in breweries. Moufang, E.
Kirn. a. d. Nahe. Allgem. Z. Bierbrau. Malzfab., vol. 43, pp. 151-155,
1915. — From bis experiments Moufang concludes that by the appli-
cation of ultra-violet rays for sterilizing barrels (by means of a spe-
cially constructed quartz lamp which could be moved through the
bunghole) the biological condition of pitched barrels may be greatly
improved, but that perfect sterilization in a biological sense is not
obtained by the present appliances.
A method for drawing off liquid in a thin layer in connection with
sterilization by ultra-violet rays. Billon-Daguerre, Compt. rend. Ac. d.
Sc, vol. 161, pp. 18-20, 1915. — After passing through a filter the
water to to sterilized enters a tank from which it passes out through
a cylinder provided with opening slots on opposite sides. The quartz
lamps are placed close to these slots, thereby forming a narrow open-
ing between the lamps and the cylinder through which the water
must pass in order to emerge. The apparatus may be mounted on an
auto truck for use in military sanitation.
Water sterilization by ultra-violet rays. Seager, J. A., Municipal
Engr., vol. 45, pp. 415-418. — There are required 160-165 watt hours
per 1,000 imperial gallons of water.
Water treatment by the aid of ultra-violet rays. Schwarz, L., and
Aumann, J. Gasbel, vol. 56, pp. 520-522; cf. Chemical Abstracts, vol.
7, p. 1069. — Various lamps, their methods of control, and their
efficiency are discussed. Certain deficiencies of the various apparatus
are pointed out, as well as the great importance of this method of
water treatment.
The sterilization of water by the aid of ultra-violet rays with a mercury-
vapor lamp. Ebert, F. A., Gesundh. Ing., vol. 37, pp. 170-171. —
Technical description of the sterilization apparatus "industry."
The sterilization of water with ulira-violet rays. Silbermann, A.,
Univer. Bern. Z. Hyg., vol. 77, pp. 189-216.— In a specially con-
structed apparatus, running water infected with pathogenic and sap-
rophytic bacteria was • exposed to ultra-violet rays. In nearly all
cases sterile water was produced. The amount of turbidity and
Decernta 12, 1919. 2834
color apparently had bo effect, although the amount of colloidal sub-
stances did have. The rate of flow had some influence, the degree
of which depended on the quality of the water.
Sterilization of water by ultra-violet rays of the mereury-vapor guaiiz
lamp. Von Recklinghausen, M., Free. Am. Inst.. Elec. ling., roll 33,
p. 1048. — To obtain ultrar-violet rays economically it is important
to study the temperature of the luminous part of the lamp. Ultra-
violet power is measured by physiological, chemical, or bacteriological
reactions. Von Recklinghausen describes the historical develop-
ment of the Hg lamp and the pistol lamp for large sterilizing units.
Different germs show different sensitivity to ultra-violet rays, though
all are destroyed on short exposure. Ultra-violet rays increase pro-
portionately more with lamp voltage than the blue or green rays to a
point above which quartz devitrifies.
Sterilization of water by ultra-violet rays of ike mercury-vapor quarts
lamp. Von Recklinghausen,, M. Discussion. Proc. Am. Inst. Elec.
Eng., vol. 33, p. 1906, 1914'. — The inverse square law holds tree in
the case of ultra-violet rays used for water sterilization if some cor-
rection is made for the line shape of the source and for some absorp-
tion in the air. Water as it comes from a modem mechanical filter
may be considered perfectly clear to the action of the rays. Such
water may be treated at a total cost of $0.60 per million gallons.
While chemical treatment may be somewhat cheaper, considering
the- expert attention required, any increased cost would be offset by a
cleaner, chemical-free H 2 0. Typhoid records from certain European
towns show a total absence of this disease since ultra-violet-ray steriliza-
tion was introduced. Regarding competition with 3 , a comparative
test run at Genoa for six months showed an equal cost for power,
but a higher first cost and operating cost for the 3 equipment.
Violet-ray sterilization for Niagara Falls fliers. Anon., Eng.
Record, vol. 69', p. 701. — Pistol lampsy 7 in each of 5 concrete canals,
will be used to sterilize 16 million gallons daily. The cost of the
canals and lamp installation will be $19,800. Approximate costs
per milHon gallons for maintenance are guaranteed as follows: Current,
7 cents; lamp renewals, based on a 2,900 hour life, 60- cents. About
1 grain per gallon of coagulant and 5 pounds of bleach per million
gallons have been used, the total cost of chemicals being about $1,50
per million gallons, it is hoped to cut down the chemical by half,
thereby making the ultra-violet treatment economical.
Purification of water by ultra-violet rays. Von Recklinghausen, M.,
J. Am. Water Works Association, vol. 1, pp. 565-588; cf. Chemical
Abstracts, vol. 8, p. 2847.— Pistol lamps with U-tubes, immersed
in the water which flows through a flume, are used at Luneville, St.
Malo, and Rouen, France, with high bacterial efficiency. A complete
historical and theoretical discussion is given.