THE CHEMICAL PURIFICATION OF SWIMMING POOLS * 



By George W. Heise and R. H. Aguilar 

 {From the Laboratory of General, Inorganic, and Physical Chemistry, 

 Bureau of Science, Manila, P. I.) 



TWO TEXT FIGURES 



The purification of swimming pools has long been the subject 

 of much study, and a vast literature has been developed con- 

 cerning it. Many methods have been suggested, notably filtra- 

 tion, sterilization with ultra-violet rays, and the use of ozone, 

 copper sulphate, liquid chlorine, and the hypochlorites of sodium, 

 magnesium, or calcium. Although these methods, or combina- 

 tions of two or more of them, have been found satisfactory under 

 most conditions, great discrepancies exist in the results recorded. 

 In spite of the fact that there are many factors influencing the 

 purification of swimming pools, many experimenters have treated 

 their particular problems as though they were of general ap- 

 plication ; hence has arisen much difference in opinion concerning 

 the relative merits of different purifying agents, amounts neces- 

 sary for efficient purification, methods of application, and the 

 like. In many cases too little attention has been paid to im- 

 portant factors such as quality of water, temperature of pool, 

 number of persons bathing, turbidity and the like to enable 

 general conclusions to be drawn from the results of different 

 workers. The treatment which is highly efficient for one water 

 under certain conditions may fail utterly for a different water 

 under slightly changed conditions. 



Of the methods mentioned, the use of chlorine either as 

 liquid chlorine or as a hypochlorite is probably the most widely 

 practiced, and because of their cheapness and because of the ease 

 with which they can be administered, hypochlorites are em- 

 ployed more than liquid chlorine. 



The work here recorded was done (1) for the purpose of 

 putting the swimming pools in Manila into a sanitary condition 

 and (2) to study the factors influencing the chemical purifica- 

 tion of swimming pools, with a view toward devising methods 

 of chemical control. It is our purpose to discuss here only the 

 chemical work done on this problem; the bacteriological work 

 done in cooperation was performed by Dr. C. E. Gabel, of the 

 Bureau of Science, and is recorded and discussed in detail 

 separately.^ 



The three installations studied, which we shall designate as 



* Received for publication November 26, 1915. 

 ^This Journal, Sec. B (1916), 11, No. 2. 



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