XI, A, 1 



Heise: Water Supply of Manila 



suming capacity are shown in Table IV, in which the analyses 

 of water, taken from the Bureau of Science tap, are added for 

 comparison. 



At the time these observations were made, chlorination at 

 the rate of approximately 0.5 part of available chlorine per 

 million parts of water was being employed. 



Table IV. — Daily variation in chlorine content and oxygen-consum- 

 ing capacity. 



[Results expressed as parts per million.] 



Date. 



1916. 



September 20. 

 September 21. 

 September 22. 

 September 23. 

 September 24. 

 September 25. 

 September 26. 

 September 27. 

 September 28. 

 September 29. 

 September 30. 



October 1 



October 2 



October 4 



October 5 



October 6 



October 7 



October 8 



October 9 



San Juan. 



Chlo- 

 rine. 



4.0 

 4.0 

 4.0 

 4.0 

 4.0 

 4.5 



3.7 

 3.7 

 4.0 

 4.9 

 4.4 

 3.8 

 8.8 

 6.8 

 3.9 

 9.4 

 4.7 

 4.4 



Oxygen 



con- 

 sumed. 



>0.8 

 0.65 

 0.77 

 0.74 

 0.73 



0.84 

 0.85 

 1.12 

 1.33 

 1.23 

 1.20 

 0.96 

 1.17 

 1.41 

 0.92 

 1.20 

 1.18 



Tap. 



Chlo- 

 rine. 



4.0 

 4.2 

 4.0 

 3.5 

 4.4 

 5.0 

 4.8 

 3.4 

 4.0 

 4.1 

 3.7 

 4.1 

 3.9 

 4.1 

 4.0 

 3.7 

 5.5 

 4.1 



Oxygen 



con- 

 sumed. 



0.65 



0.7 



0.8 



0.86 



0.88 



0.92 



1.09 

 0.94 

 1.47 

 1.44 

 2.33 

 1.40 

 2.23 

 1.59 

 1.62 

 1.09 

 1.23 

 1.49 



The results show that the oxygen-consuming capacity ' in- 

 creased greatly between the time the water entered the city 

 mains and the time it reached the Bureau of Science, indicating 

 that a large amount of organic matter was taken up by the 

 water in its course through the city distribution system. 



In order to study the chloride of lime treatment, daily bacterial 

 examinations were made both at the reservoir and at San Juan 

 bridge. The amounts of disinfectant added were varied, from 

 an addition representing 0.5 part of "available chlorine" in a 

 million parts of water to one representing 0.75 part per million. 



'Owing to the disturbing influence of small amounts of hypochlorite oa 

 the determination of oxygen consumption, the results obtained are not 

 strictly comparable with the data in Table II. 



