Improved Treatment of the Solid Deposit or Sludge from Sewage for the Application thereof to the Manufacture of Cement and other purposes.
Year: 1892

page_text: Date of Application, 23rd June, 1892
Complete Specification Left, 7th Mar., 1893—Accepted, 2nd June, 1893
PROVISIONAL SPECIFICATION.
Improved Treatment of the Solid Deposit or Sludge from Sewage
for the Application thereof to the Manufacture of Cement and
other purposes.
I, WILLIAM WEBSTER, Chemist, of The Grove, Belmont Hill, Lee, Kent, S.E.
do hereby declare the nature of this invention to be as follows:-
My invention has for its object to utilise or dispose of the solid deposit or sludge
which is obtained from sewage when subjected to the various known methods of
treatment, by making cement and fuel therefrom.
For this purpose according to one method, I mash the sludge in the wet condition
into a mixture of clay (blue gault) and chalk, or chalk and river mud or lower grey
chalk (known as "soap oľ natural cement") this being effected in any known
mashing or incorporating mill, and the mixture is run into backs and allowed to
settle.
22
The supernatent liquid having been run off the deposit is first removed to heated
floors in order to be dried, and is then burnt in kilns together with coke, or by
preference with blocks of fuel made up of ground sludge (known as
"cake")
and coke or coal breeze, the two being thoroughly incorporated with each other.
The blocks thus produced may also be used as a cheap fuel for other purposes,
as the sludge contains a considerable amount of carbonaceous and other combustible
material.
To facilitate priming, the sludge may be mixed with Portland cement and water
or with fluxed lower grey chalk. The fuel blocks thus produced are placed in
alternate layers with the above mentioned dried mixture of chalk, clay and sludge
in kilns, and is burnt in the usual manner.
The material thus produced will, when ground, form a good cement for building
and other purposes.
The grease and carbonaceous matter in the sludge will assist in the burning of
the clay and chalk, and the finely divided siliceous particles, alumina &c. will
improve the qualities of the cement and will produce slow setting when used.
Owing to the presence of the carbonaceous matters in the sludge, less coke will be
required in the burning, and consequently the manufacture of the cement will be
cheapened.
According to another method, I dry and grind the sludge and then mix it with
the chalk and clay or lower grey chalk without the use of water in a separator and
crushing mill, and I then burn the mixture as before, if necessary.
The proportions in which the above mentioned ingredients are mixed together
will depend entirely upon their composition determined by analysis.
Dated this 23rd day of June 1892.
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improved Treatment of the Solid Deposit or Sludge from Sewage
for the Application thereof to the Manufacture of Cement and
other purposes.
I, WILLIAM WEBSTER, Chemist, of The Grove, Belmont Hill, Lee, Kent S.E.
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:-
My invention has for its object to utilise or dispose of the solid deposit or sludge

page_text: which is obtained from sewage when subjected to the various known methods of
treatment, by making cement and fuel therefrom.
For this purpose according to one method, I mash the sludge in the wet condition
into a mixture of clay (blue gault) and chalk, or chalk and river mud or lower grey
chalk (known as "soap or natural cement"); this may be effected in any known
mashing or incorporating mill, and the mixture is run into backs and allowed to
settle.
The supernatent liquid having been run off, the deposit is first removed to heated
floors in order to be dried, and is then burnt in kilns together with coke, or by
preference with blocks of fuel made up of ground solid sewage sludge (known as
"cake") and coke or coal breeze, the two being thoroughly incorporated with each
other.
The blocks thus produced may also be used as a cheap fuel for other purposes,
as the sludge contains a considerable amount of carbonaceous and other combustible
material.
For producing the above described material for use as cement, I prefer to employ
the ingredients in the proportion of about one third by weight of sludge, and
two thirds of the cement materials.
The exact proportion to be employed will however entirely depend upon their
composition, which in the case of the sewage may vary considerably and which
would in each case have to be determined by analysis.
For producing the fuel blocks I employ the ingredients in the proportion of about
three fourths by weight of sludge and one third of the carbonaceous matter.
For the above described processes sludge may also be used that has been produced
by mixing with the sewage treated Portland cement or fluxed lower grey chalk for
facilitating the priming or precipitation of the sludge. The admixture of such
cement or lower grey chalk should be in the proportion of about 10 grains per
gallon of sewage containing about 38 grains of solid matter.
The fuel blocks produced as above described are placed in alternate layers with
the above mentioned dried mixture of chalk, clay and sludge in kilns, and is burnt
in the usual manner. The material thus produced will, when ground form a good
cement for building and other purposes.
The grease and carbonaceous matter in the sludge will assist in the burning of
the clay and chalk, and the finely divided siliceous particles, alumina &c. will
improve the qualities of the cement and will produce slow setting when used.
Owing to the presence of the carbonaceous matters in the sludge, less coke will be
required in the burning, and consequently the manufacture of the cement will be
cheapened.
According to another method, I dry and grind the sludge and then mix it with
the chalk and clay or lower grey chalk without the use of water in a separator and
crushing mill, and I then burn the mixture as before, if necessary.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is.:
1. The manufacture of cement by incorporating the sludge derived from the
treatment of sewage by any known process, with either clay and chalk, or chalk
and river mud, or lower grey chalk, and after separating the solid from the liquid
constituents by settlement and decantation, drying the solid matter and then burning
the sanie for use as cement substantially as described.
2. The manufacture of cement by first drying and grinding the sludge derived
from the treatment of sewage by any known process, and then incorporating it in a
dry condition with either chalk and clay, or with lower grey chalk and then burning
the mixture, substantially as described.
3. The manufacture of fuel blocks from the solid residue or "cake" obtained
from the sludge of sewage, by first grinding up such "cake," and then incorporating
it with coke or coal breeze and pressing the mixture into the form of fuel blocks

page_text: which may be used either for burning the cement referred to in the preceding
claims or for other purposes, substantially as described.
4. The admixture to the fuel compound referred to in the preceding claim of
Portland cement or fluxed lower grey chalk substantially as and for the purposes
described.
Dated this 16th day of February 1893.
ABEL & IMRAY,
Agents for the Applicant.