XI, A, 3 Heise and Aguilar: Purification of Swimming Pools 107 



water from the municipal supply is always slightly turbid, so 

 that the bottom of a pool is generally invisible. This turbidity 

 not only makes the pool unattractive and increases the danger 

 from accidental drowning, but also militates against the action 

 of disinfectants. The temperature (27°C. to 30°C.) is an added 

 factor, as it is nearer the bacterial optimum than that of typical 

 United States installations, and bacterial growth is correspond- 

 ingly stimulated. 



Obviously, filtration should be employed as a preliminary meas- 

 ure in the treatment of waters of the kind described; however, 

 the lack of filtration facilities and the desirability of improving 

 the sanitary condition of the local installations as rapidly as 

 possible made it advisable to see what could be done with chemical 

 methods of purification alone. 



In the series of experiments here recorded, chloride of lime, 

 copper sulphate, and sodium hypochlorite (antiformin) were 

 used for purification. The first was either added as a uniform 

 emulsion or was placed in a bag and dragged through the water 

 until thoroughly leached out; the last two were added in water 

 solution. 



The chemical and physical tests consisted in daily determina- 

 tions of turbidity, temperature, and chlorides and oxygen-con- 

 suming capacity, with occasional determinations of total solids, 

 alkalinity, and near the end of the work of factors influencing 

 the chemical decomposition of hypochlorites. With the exception 

 noted, the water was changed at the beginning of each week, and 

 chemicals were added to the fresh water. The analytical data 

 secured are recorded in Tables II to VII, inclusive. 



Table II. — Daily variation in quality of water. No disinfectant added. 



[Results expressed as parts per million.] 



Age of water in days. 



Pool I. a 



Pool II. b 



Pool III. c 



Chlo- 

 rides 

 (CI). 



Oxygen 



con- 

 sumed 

 (0). 



Tur- 

 bidity. 



Chlo- 

 rides 

 (01). 



Oxygen 



con- 

 sumed 

 (0). 



Chlo- 

 rides 



(CD. 



Oxygen 



con- 

 sumed 

 (O). 



Tur- 

 bidity. 



1_. 



5.0 

 4.9 

 4.7 

 4.6 

 4.7 

 5.1 



1.10 



0.9 



0.83 



1.01 



0.92 



0.97 



13.5 

 8.5 



8.4 

 8.4 

 8.8 



6.7 

 4.9 

 4.7 

 4.9 

 4.8 

 4.8 

 4.6 



• 

 1.42 



1.03 



1.06 



1.00 



1.00 



1.00 



1.11 



4.8 

 4.9 

 4.3 

 • 4.6 

 5.0 

 4.4 



1.65 

 1.86 

 1.21 

 1.32 

 1.37 

 1.42 



15.5 

 14.5 

 15.0 

 15.5 



2 



3 . 



4 . . - - 



5... 



6 



7 . 

















141426 2 



• Average temperature, 27.0° C. 

 •" Average temperature, 28.5' C. 

 " Average temperature, 27.5° C. 



Total bathers, 200. 

 Total bathers, 159. 

 Total bathers, 79. 



