Page:Popular Science Monthly Volume 58.djvu/186

178 De Varona, Engineer of Water Supply, with the writer in immediate charge.

The filtration of all surface water used for domestic supply is one of the probabilities of the future. For years many of the large cities of Europe have been supplied with filtered water, and in England alone more than ten million people are using water from which all danger from disease germs has been removed. In America filtration has gained ground but slowly, and in some of our cities the condition of the drinking-water is a disgrace to civilization. A German health officer once said to me: 'You Americans are a queer people; you filter sewage, but you drink water raw.' One reason for our tardiness in following the practice of the Old World is the fact that the conditions here are not in all respects the same as in Europe. The old methods of filtration cannot be successfully applied to many of our American waters, and water-works' engineers have felt that before expensive works were undertaken the problems should be carefully studied by direct experiment with respect to existing conditions. Thus, recent years have witnessed the operation of experimental filter plants unequalled in magnitude, in the scope of their work and in the accuracy of their methods of investigation.

The experiment station of the Massachusetts State Board of Health at Lawrence was started in 1897 and is still in operation. The results of the investigations of the principles involved in the purification of water and sewage by sand filtration have become classic in the annals of sanitary engineering, and the annual reports are still furnishing results of the highest scientific value. At the present time the work is in charge of Mr. H. W. Clark, Chemist of the Board. One practical result of these experiments was the construction of a sand filter of novel type for the purification of the water supply of the city of Eaw fence, and the immediate reduction of the typhoid fever rate showed the success of the undertaking. The water of the Merrimac River, at Lawrence, though polluted, is comparatively clear, and it became evident that methods of filtration that were applicable to water of this character would not be necessarily successful where the water was highly colored and turbid. Experiments were, therefore, begun in other cities.

In Boston, where the water was of higher color than at Lawrence, and where microscopic organisms were sometimes numerous, a filtration station was in operation from 1892 to 1895. Six sand filters, each within area, of one-thousandth of an acre, and a large number of smaller filters, were used under varying conditions. The station was in charge of Mr. Win. E. Foss, under the direction of Mr. Desmond Fitzgerald, C. E. The analytical work was done partly at the Massachusetts Institute of Technology and partly at the Biological Laboratory described above. It is much to be regretted that the results of these experiments were never published.