FILTRATION AT FREEPORT
As considerable trouble arose at Freeport, I11., from growths in its water mains, and as repeated and varying experiments had been made in the way of overcoming the evil, it was resolved to build a test filter plant. A contract was, therefore, entered into with the New York Continental Jewell Filtration company to design the plant and plan of the buildings and to erect the filter plant. The local waterworks company undertook to build all the foundations, and to erect the building and to furnish the low-service pump and connect with the filter plant at the wall of the pump house. The work was begun early in the spring of 1903. The foundation walls and reservoir underneath were made entirely of cement concrete, the building, of substantial brick construction, and the filtering and settling tanks, of three-inch red cypress. The so-called air-wash was used for washing, instead of rakes, and the entire plant was constructed by the filter company complete in every detail. The filter was started on October 13, 1903, and began a thirty days’ test run Professor E. G. Smith, of Beloit, was retained by the waterworks company to make its analyses, while Robert E. Milligan, of the New York Continental Jewell Filtration company, took charge of the plant for that firm. The plant had been started and had run for a few days before Mr. Milligan arrived, and the water had been running through the sand without any coagulant whatever. While this showed quite a remarkable reduction in the iron in the water, it also showed that there was no removal of the carbonic acid gas. On the arrival of Mr. Milligan, the use of plain lime water as a coagulant, lroin two to four grains per gallon, was employed. By this means the iron was reduced to an average of about .04 parts per 1,000,000, all the carbonic acid was entirely removed, and the water was softened from thirteen to fifteen per cent. That average has been kept up continuously, and within six months after the plant was started the crenothrix growth was absolutely stopped, and the old growth in the pipes, which had given much trouble by sloughing off and making the water roily and bad, was largely removed by heavy flushing, only a very small quantity of it being found in the mains. The growth was also found in meters, before the filter plant was installed; it has now disappeared. In some of these meters the supply of water had been very nearly stopped. The iron found in the water was metallic iron—oxide of iron in solution. Its presence was practically done away with in the filtered water, while the crenothrix growth in the mains and meters was completely stopped by removing its cause of growth—starving it out, m fact.
The shareholders of the Johannesburg, South Africa, Waterworks company have just been awarded a twelve and one-half per cent dividend.