Norfolk, Va., Tests Filter Plants.
Chief Engineer Dornin, of the Norfolk, Va., city waterworks, has just entered upon a series of experiments to ascertain if it is practicable to filter the city water by a natural instead of the present alum method. There is available for these tests $6,000, recently appropriated by the city councils tor the purpose, after two New York expert engineers had passed favorably upon Mr. Dornin’s recommendation of the proposition. The tests are being made by the waterworks force under the direction of Chief Engineer Dornin.
Two methods of natural filtration will be tried —the drive well and the infiltration galleries, the better results being expected frem tile former. There will be between two and three hundred test wells sunk, and 10 or 12 full size wells, in making the experiment—about 120 full size wells being needed if this method of filtration proves satisfactory. The test wells will lx of 2-in. pipe, and the full size wells C-in. pipe. The small wells will be used to determine as to the strata, and the large wells as to the capacity and quality of the water.
The infiltration method will consist of galleries cut in from the bank of the lake, and there will be collector pipes under the galleries. The ends of the pipes in either case—the well system or the galleries—will be of practically the same arrangement for the inoflw of the water.
It will take a great deal of equipment for the test, and require a laboratory for the analysis of the water and sand. The water from each well will be subjected to an analytical test as to its chemical and bacterial qualities. Chief Engineer Dornin has great faith in the outcome of the experiments lie is about to make, and estimates a. great saving to the city annually by natural filtration.