Hygiene and public health / by Louis C. Parkes and Henry Kenwood.

Date:
1901
Catalogue details

Licence: In copyright

Credit: Hygiene and public health / by Louis C. Parkes and Henry Kenwood. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    cause settlement of the sewer. The mortar used in jointing the bricks should be made of the best Portland cement and fine sharp sand. The Separate System.—Where it is intended to convey away sewage proper only, storm, surface, and subsoil waters being separated, the sewers need be only of small size. Under such circumstances glazed stoneware pipes, jointed with Portland cement, are generally used to form the tributaries, whilst the outfall sewer is constructed of brickwork. Cement or silicated concrete pipes have been used, especially in Germany, instead of stoneware pipes. They are said to be less brittle, to withstand extremes of climate, and to resist the chemical action of the sewage better than stoneware pipes. Under the separate system, the sewers, of whatever material, must receive water- closet sewage and waste waters only ; all rain water from roofs, yards, or areas, must be conveyed by separate pipes into surface channels at the sides of the streets, when the gradients are sufficient, or into underground channels constituting a system of drains quite distinct from the sewers. At convenient points the surface channels or underground drains should discharge into the stream or river which forms the natural drainage bed of the locality. The drainage of the subsoil should be effected by agricultural tile drains laid in the same trench, but above the sewers, and diverted into the water- courses at all suitable points. The advantages of the separate system are : (1) The volume of sewage to be conveyed outside the town is small as compared with that to be dealt with by the combined system ; its daily or seasonal fluctuations, and the total quantities to be dealt with, can be calculated approximately from the population and water-supply (points of great importance where the sewage has to be