July 3, 1907: Municipal Journal and Engineer article. Maintenance of Water Mains. “One of the subjects most freely discussed at the Toronto meeting of the American Water Works Association, and which was touched upon by several papers, was the matter of tuberculation and other stoppage of water mains, methods of cleaning them and of measuring the flow therein. Of the papers treating of these general subjects by far the most exhaustive was that of Nicholas S. Hill, Jr., of New York, entitled “Tuberculation and the Flow of Water in Pipes.” In his introduction the author says: “I wonder for how long a time water works engineers and superintendents will be willing to bury their distribution systems under four feet of earth and leave them to rust, corrode, fill up and putrefy, without means of access for inspection or cleaning.” He claims that the cost need not stand in the way of the remedy of these conditions, and that habit alone is to blame for them.
Discussing first the deposits, he says: “The various deposits which lessen the carrying capacity of water pipes and conduits may be divided into three classes: (1) Incrustations, commonly known as tuberculation, on unprotected or imperfectly protected iron pipes. (2) Deposits or growth on the inner surface of iron pipes whether protected or unprotected; the nature of the deposits depending upon the chemical constituents or biology of the water or both. (3) Accumulation of debris and mud in inverts, hollows and dead ends.” The author does not pretend to solve the disputed question as to what tubercles are, but refers to the various chemists and others who have endeavored to determine their nature, including Dr. J. C. Brown and Mr. George C. Whipple. There seems to be little question, however, that the tubercles are dependent upon iron for their existence and do not occur where there are no points of contact between iron and water.”
Commentary: On the whole, this paper is a pretty sophisticated discussion of water chemistry and the corrosion of water mains. It would be many decades before the tubercles would be identified as complex structures of iron oxides and hydroxides. A later discussion in the paper about biological growths in water mains is particularly valuable. It should be recalled that this article was published more than one year before the introduction of chlorine for disinfection purposes at Boonton Reservoir by Dr. John L. Leal. After chlorination became widespread, the flora and fauna of distribution systems changed dramatically.