Volume 3

A study of the pollution and natural purification of the Ohio river / Prepared by direction of the surgeon general.

  • United States. Public Health Service
Date:
1924-
Catalogue details

Licence: Public Domain Mark

Credit: A study of the pollution and natural purification of the Ohio river / Prepared by direction of the surgeon general. Source: Wellcome Collection.

    12/94 (page 4)
    the. pioneer work in sewage bio-chemistry carried out by the Frank lands, McGowan, Letts, Dibdin, Adeney and their coworkers ir England, and to adaptations and modifications of their methods o! study by various workers in the United States, notably Black anc Phelps, Hoover, Lederer, and Theriault. While no extended bibliog: raphy of the studies above noted will be presented in connectior with the present paper, a number of references covering certair specific points will be given in the later text. . . With the aid of the newer bio-chemistry of sewage and of the quantitative view of the oxygen relations in polluted streams whick it permits, it has been possible to formulate and test empirically ¢ general theory of stream purification from an oxygen standpoint using for this purpose the data obtained in connection with the Ohic River studies. Before proceeding with a presentation and analysis of these data, it will clarify the subsequent discussion to outline this underlying theory. THEORETICAL DISCUSSION _ The capacity of a stream to receive and oxidize sewage depend: upon its, oxygen resources. The condition of a polluted stream a any time is the result of a balance between these resources and th demand made upon them by the organic polluting matter carried by the stream. This demand, being the result of a slow bio-chemica reaction, is, in the absence of new pollution, a progressively decreas ing one, and as the resources of the stream are composed in part of : continuous influx of oxygen from the atmosphere, the state of bal ance which determines the momentary condition of the stream 1 constantly changing. There are, therefore, two primary phases 0. the problem—namely, the actual, momentary condition, and th direction and extent of the existing changes, which indicate th future condition. Fresh sewage, for example, may contain some dis solved oxygen, and, measured upon the oxygen scale of nuisance may be in the same momentary condition as a stream which has abou completed the work of oxidizing organic pollution and contains th same amount of residual dissolved oxygen. The direction of change however, is entirely different and determines the distinction betwee the two cases. The oxygen resources are comparable to the assets o a balance sheet; the oxygen demand to the liabilities. The condition of a strong sewage containing oxygen is comparable, in financia terms, to one of momentary solvency, with available cash, but witl excessive obligations maturing on the morrow. A comprehensiv theory of self-purification must therefore deal with the oxyger demand as well as with the oxygen resources, and must consider th relation of the various factors of time, temperature and other phys: