Year: 1898

page_text: Date of Application, 20th May, 1898
Complete Specification Left. 20th Feb.. 1899-Accepted, 22nd Apr., 1899
We, FRANCIS MUDIE SPENCE and DAVID DICK SPENCE, both of the Manchester
Alum Works, Manchester, in the County of Lancaster, Manufacturing Chemists, do
hereby declare the nature of this invention to be as follows:-
This invention consists in improvements in the treatment of sewage in which term
we include other similar liquids containing putrescible excrementitious substances
and soapy or fatty matters.
We have recently discovered (a) that when sulphuric acid and aluminoferric or
sulphate of alumina are added in suitable proportions to sewage in which term we
include other similar liquids containing putrescible excrementitious matters not only
are the putrescible matters precipitated, but the fat or fatty acid of the soapy or fatty
matters is also thrown down (b) that when the precipitated sludge containing the
putrescible matters and the fat or fatty acid is dried, the fat or fatty acid can be
extracted by a volatile solvent and recovered for use and the defatted nitrogenous and
phosphatic residue left by the solvent is after the solvent has been dried off an
improved manure. The present invention consists in the utilization of a liquid ferti-
lizer of the effluent produced when sewage is treated by the process above described.
We have discovered that the said process by its neutralisation of the sewage by
sulphuric acid simultaneously with its precipitation of impurities by aluminoferric or
sulphate of alumina has for the production of a liquid fertiliser the advantage over
the process of precipitation alone, that it completely precipitates the matter of a fatty
nature which as is well known tends to clog up the land over which liquid containing
such matter is made to flow and to finally render it practically impervious to the
liquid.
As the deleterious fatty matter is practically speaking completely removed by the
process aforesaid, the clear, bright, neutral effluent containing all the valuable nitro-
genous constituents of the sewage which were not precipitated in the sludge is now
in the best condition for application to land in very large quantities without any fear
of clogging or choking it up.
Our process applies only to alkaline sewages containing more alkali than can be
neutralised by the sulphuric acid present in the aluminoferric or sulphate of alumina
required to precipitate their impurities.
Dated this
1000
HOWARD CHEETHAM,
Agent for the Applicants.

page_text: We, FRANCIS MUDIE SPENCE and DAVID DICK SPENCE, both of the Manchester
Alum Works, Manchester, in the County of Lancaster, Manfacturing Chemists,
do hereby declare the nature of this invention and in what manner the same is to
he performed, to be particularly described and ascertained in and by the following
statement:-
This invention consists in improvements in the treatment of sewage in which term
we include other similar liquids containing putrescible excrementitious substances and
soapy or fatty matters.
We have recently as described in the Specification filed in respect of our Application
for Letters Patent No. 3450) dated February 11th, 1898, discovered (a) that when
sulphuric acid and aluminoferric or sulphate of alumina are added in suitable proportions
to sewage in which term we include other similar liquids containing putrescible
excrementitious matters not only are the putrescible matters precipitated, but the fat
or fatty acid of the soapy or fatty matters is also thrown down (b) that when the
precipitated sludge containing the putrescible matters and the fat or fatty acid is dried
the fat or fatty acid can be extracted by a volatile solvent and recovered for use, and
the defatted nitrogenous and phosphatic residue left by the solvent is, after the solvent.
has been dried off, an improved manure. The present invention consists in the
utilisation, as a liquid fertiliser, of the effluent produced when sewage is treated by
the process above described.
We add aluminoferric and sulphuric acid to the sewage in such quantities that the
alkilinity of the liquid is completely neutralised as indicated by methyl orange in the
way well known to chemists. We find that from 10 to 20 cwts. of aluminoferric and
about 12 to 18 cwts, of sulphuric acid of a specific gravity of 1.7 are suitable quantities
for the precipitation and neutralisation of a million gallons of ordinary town sewage,
but the quantities of the materials necessarily vary with the degree of impurity and
of alkilinity of the sewage as ascertained by tests from time to time. The alumino-
ferric may be used as is well known either in the form of slabs placed in the conduit
delivering the sewage into the precipitating tanks or of a regulated stream of the
material in solution delivered into the conduit. The acid may be delivered in the
form of a regulated stream near the same point. After the addition of the alumino-
ferric and the sulphuric acid, the clear liquid or effluent is then by any suitable means
separated from the precipitated portion or sludge.
We have discovered that the said process by its neutralisation of the sewage by
sulphuric acid simultaneously with its precipitation of impurities by aluminoferric or
sulphate of alumina has for the production of a liquid fertiliser the advantage over the
process of precipitation alone that it completely precipitates the matter of a fatty
nature which as is well known tends to clog up the land over which liquids
containing such matter are made to flow and to finally render is practically impervious
to the liquid.
As the deleterious fatty matter is practically speaking completely removed by the
process aforesaid, the clear, bright, neutral effluent containing all the valuable nitro-
genous constituents of the sewage which were not precipitated in the sludge is now
in the best condition for application to land in very large quantities without any fear
of clogging or choking it up, and we apply such effluent to land to fertilise it by 4
ntilising its well known power of withdrawing fertilising constituents from solutions
and thus also at the same time obtain a further purification of the effluent.
At the present time as the result of the inefficiency of the processes hitherto pro-
posed, almost all authorities on sewage treatment have abandoned as hopeless the
idea of profitably or economically recovering the valuable manurial constituents of

page_text: sewage, and for this reason the adoption of bacterial processes of treatment is now
being contemplated in very many localities.
As the purified and defatted effluent produced by our process contains sufficient
nitrogenous constituents to bring its potential value at present prices for sulphate of
aminonia to about nine pounds sterling per million gallons those local authorities
who do not find in the recovered fat and the defatted manure a sufficient inducement
to utilise their sewage instead of virtually destroying it by bacterial processes are
now by our invention supplied with a much stronger motive to do so; and even those
anthorities who have no irrigable land in their immediate neighbourhood will now be
enabled to utilise their sewage by passing it through pipes to districts at a consider-
able distance the outlay for the pipes being recouped by the value of the produce
obtained from the irrigating effluent.
Our process applies only to alkaline sewages containing more alkali than can be
neutralised by the sulphuric acid present in the aluminoferric or sulphate of alumina
required to precipitate their impurities.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is:
The hereinbefore described process for the treatment of sewage consisting in
purifying it from putrescible matter and fat or fatty acid by means of the addition of
aluminoferric and sulphuric acid or sulphate of alumina and sulphuric acid and
applying the clear neutral effluent containing all the valuable fertilising constituents
not precipitated in the sludge to irrigable land.
Dated this Eighteenth day of February 1899.
HOWARD CHEETHAM,
Manchester, Agent to the Applicants.