Bacteria in Delaware River, Torresdale Filters, 1913
Levels of bacteria found in the Delaware River using the Torresdale Filters for the year 1913.
This item is part of the 1914 Report on the Collection and Treatment of the Sewage of the City of Philadelphia, which can be viewed here along with two preliminary reports from 1911 and 1912. To see other illustrations from this report, click “1914 Sewage Treatment Plan” in the Subject list.
Under normal conditions of the Delaware River its water at the northern (or upstream) limits of the city is free from noticeable sewage pollution and presents an attractive appearance. The water at this point contains even in summer sufficient dissolved oxygen to justify its use for the purpose of diluting and oxidizing the effluent from the proposed sewage treatment works. But the sewage discharged into the river from towns above Philadelphia and that carried up by the flood tide from the city is evident from the almost constant presence in the water of the bacillus coli, as shown in the following table taken from the Report of the Bureau of Water for 1913.