71 
FIFTEENTH REPORT. 
OZONE AS A MEANS OF WATER PURIFICATION. 
BY R. W. PRYER, M. S., ASSISTANT IN HYGIENE, UNIVERSITY OF MICHIGAN. 
At the present day a safe water supply for a city is considered an 
absolute necessity, rather than a luxury as some people seem to think, 
and many schemes have been brought forward to purify a contaminated 
supply and place it above suspicion. 
It is unnecessary in a paper of this kind, which is merely a review 
of the literature on the subject of ozone purification, to go into any of 
the other methods in use except merely for comparison purposes. 
In the year 1891 ozone began to be used in Germany as a means of 
water purification and there are probably at the present time more 
of these plants in that country than in any other except France. One 
of the first plants of any considerable size to be installed and put into 
successful operation was that at St. Maur a dependency of Paris, France. 
The contract was first taken bv Tyndal in 1896 but the results oh- 
tained were mediocre and it was not until several years later (about 
1905 I believe) when De Frise took up the contract and modified the 
plant in various ways that the system was considered as a success. The 
success of this plant and of those installed in Germany led to the in- 
stallation of other plants and while I realize that this list is far from 
being complete it will serve to give one somewhat of an idea of the 
number of these plants that have been installed. France undoubtedly 
leads in the number of cities that have or have had all or part of their 
water supply purified in this way. Paris, Lille, Nice, Marseilles, Chartres 
and a few small towns make up the list for France. In Germany 
Paderborn, Wiesbaden, Munich and some smaller towns are using this 
system of water purification. Other cities that have all or part of 
their water supply purified in this way are Ginnekin. Holland, and St. 
Petersburg, Russia. The United States probably has a fewer number 
of these plants than any other country, unless it be England. Phila- 
delphia, Penn., had at one time an ozone plant for treating part of the 
water supply but I am not sure whether this plant is in actual success- 
ful operation at the present time. Baltimore Co., Maryland, has a 
small plant which is said to be a success and there is a small plant at 
Great Falls, South Carolina, that is reported to be doing good work. 
In regard to the plant at Ann Arbor I wish to say that I have been 
testing this for some time but that my final report will not be ready 
for publication for a few weeks yet. 
Mr. R. M. Leggett of the National Air and Water Purifying Company, 
Ann Arbor, Mich., in an address before the Central States Water 
Works Association in Detroit Sept. 24, 1912, made several statements 
with which I cannot agree. His address was published in “Water and 
Gas Review,” Oct. and Nov. numbers and one of the points with which 
I wish to take exception is as follows: Mr. Leggett is quoted as saying, 
“There is also a plant at Ann Arbor, Mich., with a capacity of three 
million gallons of water daily. This plant was started in Dec., 1910. 
