Issue 23 and Volume 25.

A NEW STYLE OF SAND FILTRATION. Among the ordinances referred to Director Thompson by the water committee of Philadelphia councils, is one for an improved system of sand filtration, by which it is proposed to place the filters on land now owned by the city adjoining the several reservoir_____, thus obviating the necessity for extensive land purchases, and applying all appropriations for the construction of the filters. It also proposes to construct plants to filter the entire water supply for $3,200,000. It is claimed that the above plan will prove itself to be efficacious, practical, durable, and inexpensive in operation. This filtration plan, as submitted to Director Thompson,does away with the natural film that forms on the top of the sand where the filtration proper takes place and catches the bacteria, and substituting for it at artificial film of mineral asbestos, which is not soluble in w iter and will…

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