James Hillhouse Fuertes
Published: 2012-06
Total Pages: 174
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Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: 330 feet to 1,020 feet. In Zurich, Switzerland, instead of extending the intake further from the shore to get pure water, a large plant has been constructed for filtering the entire supply from the lake. THE PURIFICATION OF WATER BY FILTRATION. In the following pages the works and operations necessary for the purification of drinking-water for cities and towns and large institutions, by filtration, will be described with some fulness. The science of water-purification is still in process of development. Each new experimental plant brings to light new difficulties and new methods of overcoming them. Experimental work, such as that done at Louisville, Cincinnati, Pittsburg, Providence, and Philadelphia, and now under way at New Orleans, is of incalculable value, as it leads to the discovery of the proper treatment for the purification of waters of different kinds. Processes that are applicable for the treatment of clear polluted waters fail entirely with turbid waters; and turbid waters themselves vary so greatly in regard to character and seasonal distribution of sediment that each case requires a special study. Some clear waters, also, on account of rank algag growths, at certain seasons, must have special treatment before they can be filtered successfully. The filters described at length in this work are classified under two heads?slow sand-filters and rapid sand-filters. These terms must be used in the restricted sense; both refer to filters in which thefiltering medium is sand. The slow sand-filters may be, though they generally are not, operated with the aid of chemicals for producing the surface film, while the rapid sand-filters can only be efficient by using a coagulant, such as aluminum hydrate, to form the film artificially and rapidly. Other types, such as th...