St. Johnsbury, Vt. (E. & T. Fairbanks & Co.) These filters were built about 30 years ago, and have been recently enlarged. The filters were originally open, but were afterwards covered with a roof. The single roof proved inadequate to keep them from freezing, and a second roof was added inside and under the main roof. They are used for filtering pond water, which is quite clear and not subject to much pollution. The water supply is one of two, the other is the town supply and is taken from the Passumpsic River. No published description.
Nantucket, Mass. Designed by J. B. Rider, built in 1892. This filter is used to remove organisms from the reservoir water supply. It is only used when the organisms are troublesome, and is satisfactory in preventing the tastes and odors which formerly resulted from their presence. Description: Jour. N. E. Water Works Assoc., Vol. 8, p. 171; Eng. News, Vol. 31, p. 336.
Lawrence, Mass. Designed by Hiram F. Mills, built in 1892-3, and put in operation September, 1893. It is used for treating the water of the Merrimac River, which contains a large amount of sewage. Description: Report of the Mass. State Board of Health, 1893, p. 543; Jour. N. E. Water Works Assoc., Vol. 9, p. 44; Eng. News, Vol. 30, p. 97.
Ilion, N. Y. Designed by the Stanwix Engineering Company and are used for treating reservoir water, which is generally clear and not subject to pollution. Description: Eng. News, Vol. 31, p. 466.
Mount Vernon, N. Y. (New York Suburban Water Company.) Designed by J. N. Chester, built in 1894. These filters are similar in general construction to the Lawrence filter, although the dimensions both vertical and horizontal are reduced, and the area is divided into three parts. The filters are used for treating reservoir water, which is generally quite clear, but which is polluted by a considerable amount of sewage. Since the use of filters the reduction in the typhoid fever death-rate has been very great. Description: Eng. News, Vol. 32, p. 155.
Milford, Mass. Designed by F. L. Northrop. This filter is very simple in construction, and is used for filtering Charles River water as an auxiliary supply. Description: Jour. N. E. Water Works Assoc., Vol. 10, p. 262.
Grand Forks, N. D. Designed by W. S. Russell. These filters are covered with roofs. They treat the water from the Red River, which is very muddy, and also sewage-polluted, and which formerly caused typhoid fever. Description: Eng. News, Vol. 33, p. 341.
Ashland, Wis. Designed by William Wheeler, built in 1895. The Ashland filters were the first vaulted masonry filters to be constructed in the United States, and are used for treating the bay water, which is polluted with sewage, and is at times muddy from the river water discharging into the bay near the intake. The filters are below the bay level, and receive water from it by gravity. Description: Jour. N. E. Water Works Assoc., Vol. 11, p. 301; Eng. News, Vol. 38, p. 338.
Lambertville, N. J. Designed by Churchill Hungerford, and built in 1896. These are open filters with earth embankments, for filtration of reservoir water. Description: Eng. News, Vol. 36, p. 4.
Far Rockaway, L. I. (Queens County Water Company.) Designed by Charles R. Bettes, Engineer in Charge; Charles B. Brush & Co., Chief Engineers; and Allen Hazen, Consulting Engineer. Constructed in 1896. These masonry filters were used for the removal of iron from well waters. They are also designed to be suitable for the filtration of certain brook waters which are available as auxiliary supplies, but the brook water has been but rarely used. Description: Eng. Record, Vol. 40, p. 412.