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: Purification Of Water. It is highly desirable that the water supply of a community should, as far as possible, be free from all foreign and polluting ingredients. Nearly all waters derived from natural sources contain such ingredients, and the various processes of purification aim at their elimination. The foreign ingredients may be divided broadly into mineral and organic matters. As we have seen, most of the spring and deep well-waters, many shallow well- waters, and to a less extent the various river waters, contain the salts of lime and magnesia, which render these waters hard. The removal of these salts, and the production of softer water, is eminently desirable for economic purposes ; and, occasionally, to improve the potability and wholesomeness of the water, when the salts are in great excess, or are chiefly of the kind producing permanent hardness. The removal of the organic matters, suspended or dissolved in water, is another and still more important object in any process aiming at complete purification. We shall now proceed, first, to the consideration of those processes which are—or could be—undertaken on a large scale for the purification of water before its distribution to the consumers; and secondly, to such processes of domestic purification as may be undertaken on his own premises by the consumer, who has received his water from a public source, but is not satisfied with its quality, and desires if possible its still further purification. What should be aimed at is, to procure at its source a water sufficiently good to require no artificial purification ; but failing this, the water should be efficiently purified before its distribution to the consumers. It is certainly not wise to leave the purification to individual effort. Purification on a large scale...