A Process for Treating Sewer Water, with the Double Object of Improving its Sanitary Condition and Separating and Utilizing the Substances contained in it.
Year: 1895

page_text: Date of Application, 26th June, 1895
Complete Specification Left, 21st Mar., 1896-Accepted, 26th June, 1896
PROVISIONAL SPECIFICATION.
A Process for Treating Sewer Water, with the Double Object of
Improving its Sanitary Condition and Separating and Utilizing
the Substances contained in it.
I, ETIENNE DUSSAU of 13 Rue Léon Cogniet, Paris, France, Chemical
Engineer, do hereby declare the nature of this invention to be as follows:-
On leaving the sewer the liquid is first received in a basin where it remains in
perfect stillness for three hours, it then flows by gravitation into a channel where
it is subjected to a jet of fluoric gas.
Fluoric gas is composed of hydro-fluoric-acid gas and fluoric gas of silicium.
It is produced by the direct reaction of sulphuric acid upon ordinary fluor spar
in presence of some silicate.
The sulphuric acid in combination with the fluor spar produces hydro-fluoric
acid, and the presence of a silicate under whatever form, at the moment of the
re-action, produces gas of fluoride of silicium.
For the commencement of this action the fluoric gas is supplied by foreign
substances in the water. In the ordinary course it arises from the deposit in the
basins of precipitation.
If this deposit is mixed immediately after being left, with a current of water it
becomes changed into fluorides, and hydro-fluo-silicates, which in turn produce
fluoric gas.
By its contact with the water this gas is immediately decomposed, and hydro-
fluoric gas is dissolved, the gas of fluoride of silicium becomes changed into
bydro-fluo-silic acid and free silicia, which both dissolve.
The fluoric gas is regenerated easily, and precipitates the potash of the water,
which it renders aseptic.
The liquid is conducted into a second basin where it is again purified by
depositing insoluble matter. From this it proceeds to a third, through a chanuel,
the bed of which has a tube conveying compressed air.
In the third basin are produced simultaneously precipitates of fluorides of calcium,
of hydro-fluo-silicate of potash, of phosphates, and above all of ammoniated
magnesia, of sulphates, of carbonate of lime, of free silicia, a little clay and some
chlorides, of some oxide of iron and traces of organic matter.
If this mixture be dried and treated with fluoride of silicium in which are
proportionate parts of silicium to the matter treated, such will be the general
character of the reaction, in spite of small quantities of carbonic, sulphuric and
hydro-chloric acids, which arise during distillation.
This completes the treatment of the fluid.
The soluble matter left in the basins of precipitation is then treated for the
purpose of obtaining fat and organic matter, and their almost complete separation
from the fluid. For this purpose the operation of precipitation may be retarded
by lime which ought to be done after ten successive days of flowing off, and one
then proceeds as follows:-
One stirs up the deposit soaking in the water in the form of clear pulp, a strong
current of warm compressed air, for three or four hours, by means of a suitable
apparatus, one then rewarms the mass by means of steam introduced by the same
apparatus, to a temperature of 60°, keeping it so for three or four hours, after
which one throws into it a powerful jet of cold air.

page_text: The mass is then turgid and covered with an impure scum containing fat, this is
removed immediately it rises and is purified by well known processes; the water
is then drawn off, and the residue is employed for producing lighting gas, or as
fuel, or as a source for the production of phosphoric acid and potash.
The deposit formed in the second basin is very weak and almost entirely consists
of organic matter deprived of azote.
Dated thi. 04th din Tu1005
S. S. BROMHEAD,
97 Newgate Street, London, Agent for Applicant."
COMPLETE SPECIFICATION:
A. Process for Treating Sewer Water, with the Double Object of
Improving its Sanitary Condition and Separating and Utilizing
the Substances contained in it.
r
I, ETIENNE DUSSAU of 13 Rue Leon Cogniet, Paris, France, Chemical
Engineer, 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 following statement:-
On leaving the sewer the liquid is first received in a basin where it remains in
perfect stillness for three hours, it then flows by gravitation into a channel
where it is subjected to a jet of hydrofluoric acid gas combined with fluoride of
silicium gas.
By its contact with the water this combined gas is immediately decomposed, and
hydrofluoric acid gas is dissolved, the gas of fluoride of silicium becomes changed
into hydrofluosilicic acid and free silica which is also disolved.
The combined hydrofluoric acid gas and fluoride of silicium gas precipitates the
potash of the water, which it renders asceptic.
The liquid is conducted into a second basin where it deposits insoluble matter.
From this it proceeds to a third, through a channel, the bed of which has a tube
conveying compressed air for stirring up the mass.
In the third basin are simultaneously produced by addition of lime, precipitates
of fluoride of calcium of hydrofluosilicate of potash, of phosphates and above all
of ammoniated phosphate of magnesium, of sulphates, of carbonate of lime, of free
silica a little clay and some chlorides of some oxide of iron and traces of organic
matter.
The matter left in the first basin is then treated for the purpose of obtaining fat
and its almost complete separation from the fluid.
For this purpose the operation of precipitation by lime, which ought to be done
after. ten successive days of flowing off, may be retarded, and the operation proceeds
as follows:
The deposit soaking in the water in the form of a clear pulp is stirred up with a
strong current of warm compressed air, for three or four hours, by means of
a suitable apparatus. The mass is then rewarmed by means of a steam introduced
by the same apparatus, to a temperature of 60° C. remaining for three or four hours,
after which a powerful jet of cold air is introduced into it..
The mass is then turgid and covered with an impure scum containing fat, this is
removed immediately it rises and is purified by well known processes, the water
is then drawn is then drawn off, towards the third basin, and the residue is employed
for several suitable uses.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is.
A process for treating sewer water in order to purify the same and to extract the

page_text: substances contained therein (1) by spontaneous decantation, (2) by disinfecting
same by means of combined hydrofluoric acid gas and fluoride of silicium gas
(3) by precipitation of insoluble matters by means of lime (4) by coagulation of
the fatty matters by means of successive currents of compressed air, steam and
cold air, as herein described and explained.
Dated this 21st day of March 1896
S. S. BROMHEAD,
97 Newgate Street, London, Patent Agent.