Metropolitan sewers. 1 Greek Street, 22nd June, 1849. Sir.

  • Lovick, Thomas.
Date:
[1849]
Catalogue details

Licence: Public Domain Mark

Credit: Metropolitan sewers. 1 Greek Street, 22nd June, 1849. Sir. Source: Wellcome Collection.

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    No. -19.] ^metropolitan §3>e\im*s. Sir, 1 Greek street, *22nd June, 1849. In answer to your question, “ What would be the size of sewer that would take the main flow of house sewage of the Metropolis, taking as the data the results of the experiments in Earl street, of the flow upon an ordinary day, not a water-day, AND EXCLUSIVE OF ALL SURFACE AND STORM WATERS ?” I Stated to you that a pipe less than three feet in diameter would be sufficient. As there appears to have been a misconception of this statement, I deem it necessary that you should be in possession of the data upon which it was based. You are aware that for some time past I have been carrying on, by the order of the Court, experiments on the flow of sewage (from between 11 and 1200 houses) through 15-inch pipes, laid in the Earl- street sewer, by direct admeasurement of the flow, at stated periods, through the 24 hours of the day and night. From actual observations the 22nd and 27th Feb.— 3rd, 6th, 8th, 10th, 13th, and 15th of March, continued through the 24 hours—days upon which there was no supply of water to the houses from the Companies, and none from the surface or from storms —a mean flow was deduced of 5‘85 cubic feet per minute, occupying a sectional area in the pipe of about 8^ inches, equal to a circle of about Bf inches in diameter, and representing the flow as above from nearly 1200 houses. It was found that the greatest flow on the days when water was sup¬ plied to the houses by the Companies was 150 cubic feet per minute, with a mean velocity of 3*6 feet per second, and that the sectional area occupied in the 15-inch pipe by this flow was about 100 inches. As it was considered that a merely proximate, although at the same time a maximum estimate was required, I took the results of the actual observations on the ordinary davs of the mean flow of house-drainage only, as data for esti- mating the mean flow of the whole of the Metropolis, assuming, of course, the flow in all other places—other things being equal—to be proportionate to the flow ob¬ served in the Earl-street sewer; and for the size of pipe that would accommodate this flow, the data given by observations on the greatest flow on water-days, as affording results approximating much more nearly to the flow through a larger pipe. ( 44 ) v},'