The question of the value, the uses, and the best means of collecting
for use, the great mass of the sewage of the metropolis, seems to have
become complicated by the statements which have been of late years put
forth by rival projectors and rival companies. In our smaller country
towns, the neighbourhood of many being remarkable for fertility and for
a green beauty of meadow-land and pasturage, the refuse of the towns,
whether sewage or cesspoolage (if not washed into a current, stream,
or river), is purchased by the farmers, and carted by them to spread
upon the land.
By _sewage_, I mean the contents of the _sewerage_, or of the series
of sewers; which neither at present nor, I believe, at any former
period, has been applied to any useful or profitable purpose by the
metropolitan authorities. The readiest mode to get rid of it, without
any care about ultimate consequences, has always been resorted to, and
that mode has been to convey it into the Thames, and leave the rest to
the current of the stream. But the Thames has its ebbs as well as its
flow, and the consequence is the sewage is _never_ got rid of.
The most eminent of our engineers have agreed that it is a very
important consideration how this sewage should be not only innocuously
but profitably disposed of; and if not profitably, in an immediate
money return, to those who may be considered its owners (the municipal
authorities of the kingdom), at least profitably in a national point of
view, by its use in the restoration or enrichment of the fertility of
the soil, and the consequent increase of the food of man and beast.
Sir George Staunton has pronounced some of the tea-growing parts of
China to be as blooming as an English nobleman’s flower-garden. Every
jot of manure, human ordure, and all else, is minutely collected, even
by the poorest.
I have already given a popular account of the composition of the
metropolitan sewage, &c. (under the head of Wet Refuse), and I now give
its scientific analysis.
In some districts the sewage is more or less liquid--in what proportion
has not been ascertained--and I give, in the first place, an analysis
of the sewage of the King’s Scholars’ Pond Sewer, Westminster, the
result having been laid before a Committee of the House of Commons.
As the contents of the great majority of sewers _must_ be the same,
because resulting from the same natural or universally domestic
causes (as in the refuse of cookery, washing, surface-water, &c.),
the analysis of the sewage of the King’s Scholars’ Pond Sewer may be
accepted as one of sewer-matter generally.
Evidence was given before the committee as to the proportion of
“land-drainage _water_” to what was really _manure_, in the matter
derived from the sewer in question. A produce of 140 grains of manure
was derived from a gallon of sewer-water. Messrs. Brande and Cooper,
the analyzers, also state that one gallon (10 lbs.?) of the liquid
portion of the sewage, evaporated to dryness, gave 85·3 grains of solid
matter, 74·8 grains of which was again soluble, and contained--
Ammonia 3·29
Sulphuric acid 0·62
Phosphate of lime 0·29
Lime 6·25
Chlorine 10·00
“and potass and soda, with a large quantity of soluble and vegetable
matter, and 10·54 insoluble.”