Sewer ventilation and sewage treatment / [R. Harris Reeves].

  • Reeves, R. Harris.
Date:
1889
Catalogue details

Licence: Public Domain Mark

Credit: Sewer ventilation and sewage treatment / [R. Harris Reeves]. Source: Wellcome Collection.

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    the air forms one of the greatest motive powers in producing air currents in sewers and drains. Given a 12-inch pipe sewer which fills at A, Fig. 2, as is often the case during a heavy rainfall, or even during the discharge of a flushing tank, partial stoppage will take place. A portion of the worst air on a system already formed in the drain B, while the filling of sewer A is proceeding, is driven through the trap C by the lifting of the water at E, through which it passes, and in doing this the air is washed, and would probably leave its worst germs in the liquid. But when the cause of the drain filling had stopped, it would commence to lower itself, and in doing this the sewage would act as the plunger of a pump, creating a vacuum behind it, and drawing the water out of the trap C, leaving a free passage at D, Fig. 3, for the sewer air (which may have been for months oscillating to-and-fro in contact with the sewage) to enter the branch drains F, and through them the houses. Even the mere act of flushing sewers will produce this vacuum, and so lower the water in the trap. In summer time this air in the various branch drains attached to the main sew'er, forms the worst gases that can be found in any part of a system of drainage. The reason of this is that the water passing the intercepting trap from the branch drains drives out into the sewer a cor- responding amount of air to the level to which
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