March 7, 1912: Municipal Journalarticle. Some Principles of Sewerage Design. “The report of the Sewerage Commission upon the problem presented by the city of Milwaukee, the general conclusions of which were referred to in our issue of Feb. 29, contains a number of features among its details which are of considerable interest. One of these is the quantity of sewage which the engineers, Messrs. Alvord, Eddy and Whipple, think it desirable to provide for. The maximum rate of flow of sewage at the present time is approximately 250 gallons per capita per day, this including water used in manufacturing and ground water leaking into the sewers. The proposed sewer system is estimated of a capacity sufficient for the population and other requirements of the year 1950, and the maximum flow at that time is estimated at 350 gallons per capita per day. As the amount of ground water seepage per capita will probably be less rather than greater at that time, this indicates a belief in a very high rate of water consumption for domestic and manufacturing purposes 40 years hence. The importance, in their opinion, of manufacturing wastes in such a calculation is indicated by the fact that more than three times as much sewage per acre is allowed for from the manufacturing as from the residential areas.
In making provisions for the future, the engineers believe that this should be governed to a great extent by the possibilities of gradual enlargement of capacity of the work in question. Thus sewers, the capacity of which can be increased only at great expense, they think should be designed for the probable needs of the city in 1950; while the sewage purification works, which can be easily enlarged by the addition of small units, they think should be constructed at the present time for a capacity of only 15 or 20 years in advance. An additional argument in favor of the latter is that our knowledge concerning purification methods is continually increasing, and it is very probable that improvements in details, if not in actual principles of operation will be available by that time.”
Reference: “Some Principles of Sewerage Design.” 1912. Municipal Journal. 32:10(March 7, 1912): 349.
Commentary: The three prominent engineers (Alvord, Eddy and Whipple) were wise to not lock in treatment technology in 1912 for 50 years. They knew that the knowledge in this area of sanitary engineering was advancing at a significant rate. They wanted their client to benefit from such a technological advance when it occurred some years in the future.