Improvements in the Utilization of Sewage Sludge and in the Production of Filtering and Purifying Material therefrom.
Year: 1891

page_text: Date of Application, 10th Oct., 1891
Complete Specification Left, 28th June, 1892—Accepted, 30th July, 1892
PROVISIONAL SPECIFICATION.
Improvements in the Utilization of Sewage Sludge and in the
Production of Filtering and Purifying Material therefrom.
I THOMAS BRIGHT WILSON of 37 Arcade Chambers, St. Mary's Gate
Manchester in the County of Lancaster Civil Engineer do hereby declare the
nature of this invention to be as follows --
My said invention consists mainly in the production of an improved material
suitable for use in filtering and purifying sewage or polluted waters the said
material being obtained by treating the sludge of sewage or polluted waters con-
taining oxides of iron or to which salts of iron or perchloride of iron have or has
been added for the purposes of precipitation as is well understood. In precipitating
sewage and the like by iron perchloride the organic matter in suspension is thrown
down along with mineral or inorganic matter and a proportion of per-oxide and
sulphide of iron. I dry the resulting sludge by exposure to the atmosphere as
usual having first pressed out superfluous moisture by means of the ordinary
presses. I then further dry the sludge by suitable means such as stoves and lastly
calcine the material at a low red heat in closed retorts or otherwise allowing the
waste gases to escape after purification when necessary or collecting them for
utilization. The action of the heat partly carbonises the organic material and,
partly drives it off in the form of steam or other gases. The per-oxide of iron in
the sludge in its carbonised condition is reduced to the state of magnetic oxide
which partly becomes assimilated with the carbon. The heat also drives off the
sulphur from the sulphide of iron the iron becoming oxidised and carbonised. The
material thus treated is allowed to cool out of contact with the atmosphere or
beneath water or other liquid. The resulting product or material is found to be
of great value as a filtering and purifying means for sewage. The means for
carbonising the sludge may be greatly varied. For example where the process is
carried out on a large scale I propose to use a closed furnace which might be
heated with producer gas as in the well known Siemens and other furnaces or with
coal or oil or water gas or with natural gas or gas evolved from the sludge itself.
In places where the process would not constitute a nuisance the dried sludge could
be calcined by means of fuel in heaps or kilns the outside of the heaps being
protected from the atmosphere by a coating of clay, sludge or the like. Sufficient
air is admitted to burn the organic matter and until the stack has become heated
to a dull red heat, whereupon the admission of air is stopped and the carbonisation
with the accompanying reduction of the iron oxide to the magnetic state is effected.
When the iron in the sludge is insufficient in quantity I may add enough of iron
ore to make up for the deficiency.
Dated this 9th day of Octol 1801.
DUTTON & FULTON,
1, St. James Square, Manchester, Agents.
COMPLETE SPECIFICATION.
10 Improvements in the Utilization of Sewage Sludge and in the
Production of Filtering and Purifying Material therefrom.
I THOMAS BRIGHT WILSON of 37 Arcade Chambers, St. Mary's Gate,
Manchester, in the County of Lancaster, Civil Engineer, do hereby declare the
nature of this invention and in what manner the same is to be performed to
Pied1

page_text: be particularly described and ascertained in and by the following statement that is
to say :-
My said invention consists mainly in the production of an improved material
suitable for use in filtering and purifying sewage or polluted waters, the said
material being obtained by treating the sludge of sewage or polluted waters con-
taining oxides of iron or to which salts of iron or perchloride of iron have or has
been added for the purposes of precipitation as is well understood. In precipitating
sewage and the like by iron perchloride or persulphate the organic matter in
suspension is thrown down along with mineral or inorganic matter and a proportion
of the per-oxide and sulphide of iron. I dry the resulting sludge by exposure to
the atmosphere as usual and press out superfluous moisture by means of the
ordinary presses or I may dry the sludge by suitable means such as stoves after
the air drying and lastly calcine the material at a low red heat in closed retorts
or in coke ovens or in chambers attached to destructor furnaces employed at works
for dealing with town refuse or otherwise, allowing the waste gases to escape after
purification when necessary or collecting them for utilization. The action of the
heat partly carbonises the organic material and partly drives it off in the form
of steam or other gases. The per-oxide of iron in the sludge in its carbonised
condition is reduced to the state of magnetic oxide which partly becomes assimilated
with the carbon. The heat also drives off the sulphur from the sulphide of iron,
the iron becoming oxidised and carbonised.
The material thus treated is allowed to cool out of contact with the atmosphere
or beneath water or other liquid. The resulting product or material is found to be
of great value as a filtering and purifying means for sewage. The means for
carbonising the sludge may be greatly varied. For example where the process is
carried out on a large scale I propose to use a closed furnace which might be
heated with producer gas as in the well known Siemens and other furnaces or with
coal or oil or water gas or with natural gas or gas evolved from the sludge itself,
or be attached to a destructor furnace. In places where the process would not
constitute a nuisance the dried sludge could be calcined by means of fuel in heaps
or kilns the outside of the heaps being protected from the atmosphere by a coating
of clay, sludge or the like.
Sufficient air is admitted to burn the organic matter and until the slack has
become heated to a dull red heat, whereupon the admission of air is stopped and
the carbonisation with the accompanying reduction of iron oxide to the magnetic
state is effected.
When the iron in the sludge is insufficient in quantity I may add enough of
iron ore or any waste oxide of iron to make up for the deficiency.
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
1) The improved material for filtering and purifying sewage and impure water,
the said material being obtained by drying and calcining the sludge of sewage
and impure water containing oxides or salts of iron substantially as herein set
forth.
2) The improved method of treating the sludge of sewage and polluted waters
containing oxides or salts of iron by thoroughly drying the sludge and calcining it
in closed retorts or coke ovens or otherwise, for the purpose of obtaining a
material suitable for purifying and filtering sewage and the like substantially as
hereinbefore described.
Tinted Lit T... 1000
E. K. DUTTON & Co.,
5, John Dalton Street, Manchester, Agents.