Improvements in the Treatment of Sewage.
Year: 1898

page_text: Improvements in the Treatment of Sewage.
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 and has for its object not only such an
efficient precipitation of the putrescible matter together with the fat or fatty acid
of the soapy or fatty matters from the sewage as will enable us to produce a clear,
bright and permanently non-putrescible effluent but also such an efficient separa-
tion of the fat or fatty acid of the soapy or fatty matter from the putrescible
matter as will enable us both to utilize the fatty matter and obtain a manure
better than that hitherto produced from the putrescible matter of sewage.
According to this invention we treat sewage with aluminoferric or sulphate of
alumina and with sulphuric acid in such proportions that the putrescible matter
and the fat or fatty acid of the soapy or fatty matters are precipitated and the
alkalinity of the liquor is at the same time completely neutralised. The clear
liquid is then by any suitable means separated from the precipitated portion or
sludge. The precipitated portion or sludge is freed by pressing and drying or by
any other suitable means from the greater part of the liquid associated with it.
The dried sludge is then treated in a suitable vessel or suitable vessels with ether
or bisulphide of carbon or petroleum spirit or with
other suitable
solvent or solvents with the object of dissolving out the fat or fatty
acid contained in such dried sludge. The resultant liquid consisting
of the solvent or solvents used and the fat or fatty acid dissolved therein is then
separated by filtration or otherwise from the insoluble solid portion and the fat
or fatty acid in such liquid is then separated from the solvent or solvents by
distilling off the solvent or solvents or by any other suitable means which will
The fat or fatty
enable the solvent or solvents to be recovered for further use.
any
acid may be utilized for any purpose for which it may be suitable either in the
form in which it is obtained after separation from the solvent or solvents or
after being subjected to any purification which may be requisite. The insoluble
portion of the sludge contains phosphoric acid and albuminoid matter and may
be dried in any suitable way and utilized as a manure.
1000
HOWARD
CHEETHAM.
Manchester, Agent to the Applicants.

page_text: Improvements in the Treatment of Sewage.
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 and in what manner the same is
to be performed, to be particularly described and ascertained in and by the follow-
ing statement:-
-
This invention consists in improvements in the treatment of sewage in which
teim we include other similar liquids containing putrescible excrementitious
substances and soapy or fatty matters and has for its object not only such an
efficient precipitation of the putrescible matter together with the fat or fatty acid
of the soapy or fatty matters from the sewage as will enable us to produce a clear,
bright and permanently non-putrescible effluent but also such an efficient sèpara-
tion of the fat or fatty acid of the soapy or fatty matter from the putrescible
matter as will enable us both to utilise the fatty matter and obtain a manure
better than that hitherto produced from the putrescible matter of sewage.
According to this invention we treat sewage with aluminoferric or sulphate of
alumina and with sulphuric acid in such proportions that the putrescible matter
and the fat or fatty acid of the soapy or fatty matters are precipitated and the
alkalinity of the liquid is at the same time 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 17 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 alkalinity of the sewage as
ascertained by tests from time to time. The aluminoferric 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.
The acid may be delivered in the form of a regulated stream near the same point.
After the addition of the aluminoferric and the sulphuric acid, the clear liquid
or effluent is then by any suitable means separated from the precipitated portion
or sludge.
The precipitated portion or sludge is freed or practically freed by pressing and
drying or by any other suitable means from the water associated with it. The
dried sludge is then treated in a suitable vessel with a solvent which may be
ether or bisulphide of carbon or petroleum spirit or any other suitable solvent or
may be a mixture of two or more or all of such solvents, with the object of
dissolving out the fat or fatty acid contained in such dried sludge. The resultant
liquid consisting of the solvent used and the fat or fatty acid dissolved therein,
is then separated by filtration or otherwise from the insoluble solid portion. The
fat or fatty acid dissolved in such liquid is then separated from the solvent by
distilling off and condensing the solvent or by any other suitable means which
will enable the solvent to be recovered for further use.
The fat or fatty acid may then be utilised for any purpose for which it may be
suitable either in the form in which it may be after separation from the solvent or
after being subjected to any process of purification which may be requisite such
for instance as that of distillation in a current of superheated steam.
The portion of the sludge which was insoluble in the solvent used contains
phosphoric acid and nitrogenous matter and after drying it in any suitable way
free from the solvent and taking care to recover the latter for futher use, we
utilise the said insoluble portion of the sludge as a manure. Unlike the dried

page_text: sludge produced by precipitation from a highly alkaline sewage without
neutralisation which contains a portion of fatty acid in combination with
the lime originally present in the sewage, the dried sludge obtained by our here-
inbefore described process is free from fatty matter and is thus not only enriched
in phosphoric acid and nitrogenous matter but is freed from a manurially injurious
constituent.
Our process applies only to alkaline sewages containing more alkali than can be
neutralised by the sulphuric acid present in the aluminoferric required to pre-
cipitate their putrescible matter.
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:
1. The herein before described process for the treatment of sewage whereby
concurrently with its purification its fat or fatty acid is obtained from it sub-
stantially as described."
2. The hereinbefore described process for the treatment of sewage whereby
concurrently with its purification a de-fatted manure is obtained from it sub-
stantially as described.
3. The herein before described process for the treatment of sewage whereby con-
currently with its purification its fat or fatty acid and also a defatted manure are
cbtained from it substantially as described.
Dated this Tenth day of December 1898.
HOWARD CHEETHAM.
Agent for the Applicants.