Issue 20 and Volume 45.

FILTRATION Since it was installed, the new filter at Harrisburg, Pa., has always removed all-turbidity and color. A daily average of only 19 bacteria has been removed—making an elimination of 99.62 per cent. On 300 days in the year the number of bacteria remaining in the filtered water was under 25, and was over 100 on fourteen days only. Tests for bacilli coli in the filtered water also showed a more satisfactory elimination than in other years, the average for the entire year being slightly over 1 per cent., while the river water showed it present in 66 per cent, of the samples taken. The turbidity in the river water during the year ranged from 1 part to 1,400 parts per 1,000,000; color from 1 to 30; alkalinity, 6 to 138 parts; bacteria, from 135 to 120,000 per C. C. An average turbidity of 52. color, 9; alkalinity, 55, and…

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