December 17, 1914: Municipal Journalarticle—Small Sewage Treatment Plant. “The Home for the Indigent of Delaware County, Pa., is located in Middletown Township, near the village of Lima, and on the main highway leading from Media to West Chester, Pa. There are usually about 125 inmates the home, although during the winter months the number runs higher. With employees, etc., the number of persons contributing to the sewer system will average about 140.
The sewage flow varies considerably on different days. When the laundry is being operated, the total daily flow to about 10,000 gallons, 60 per cent of which runs off in about 6 hours. On all other days, the total flow amounts to about 4,000 gallons.
The plant consists of an Imhoff tank, dosing chamber, percolating filter, secondary tank and sand filter, as shown on the general plan. Both the sewer system and treatment plant operate by gravity….
The plant has now been in operation for about one year and has given perfect satisfaction. No odors are noticeable at any portion of the plant. The sewage is kept in a fresh state and is passed through the plant as rapidly as consistent with the degree of purification necessary.
The Imhoff tank has fully demonstrated its value even in an installation as small as this. The incoming sewage is kept fresh and free from the “blown up” sludge, so common in both plain settling tanks and septic tanks. At a recent inspection by the authors, the vents were covered with scum about 6 inches thick and considerable gas was being produced and given off. This gas was entirely inodorous and inflammable, which substantiated the claim of the inventor.”