Small sewage tanks / issued by the Division of Sanitary Engineering of the Commonwealth Department of Health under the authority of the Minister for Health.

Date:
[between Dec. 1922 and Nov. 1924]
Catalogue details

Licence: In copyright

Credit: Small sewage tanks / issued by the Division of Sanitary Engineering of the Commonwealth Department of Health under the authority of the Minister for Health. Source: Wellcome Collection.

    18/30 (page 16)
    Disposal of Effluent. In fifteen of the 38 installations the final effluent is discharged direct into a stream or other large body of water. In four of these the tank effluent is passed through an oxidizing filter. In nine other installa- tions the final effluent is disposed of on the surface of the ground, and in six cases out of the nine the tank effluent is passed through an oxidizing bed before final disposal. In twelve other installations the final effluent is disposed of beneath the surface of the ground, and in five of these the tank effluent is passed through an oxidizing filter before final disposal. In one case the effluent goes direct into a street channel. SEWAGE TANK TROUBLES AND MEANS OF AVOIDING THEM. There are various ways in which a sewage tank may be troublesome, among which are the following :— | 1. Its design and construction may be wrong. 2. Its design and construction may be satisfactory, but it may be unfortunately placed with reference to its surroundings. The openings for the flow of liquids may become stopped up. There may be an excessive accumulation of solids. | . The cleaning out of the tank may be left too long. . There may be objectionable odours. . There may be troubles with oxidizing beds attached to the sewage tank. 8. Stoppages may occur in the drains connected with the tanks. 9. The disposal of the effluent may be imperfect. “I> Ot HR CO A discussion of these troubles, their causes, and means of avoiding them, appeals to me as being a useful means of guidance in arriving at suitable designs and satisfactory conditions of operation. If a tank is designed along rational lines a good beginning is made towards satisfaction in its use. And what are “rational lines”? Some idea of this is indicated by the preceding discussion of the record of the 38 installations, but I will here take it up more specifically. . In the design of a sewage tank the following are the outstanding controlled conditions :— | 1. The kinds of wastes, whether human wastes only, or whether other domestic wastes; and whether any wastes are likely to be included which might interfere with biological action in the tank. 2. The degree of purification required governed by conditions relating to the ultimate disposal of the sewage liquids after they leave the tank. : 3. The number of people contributing sewage.