AN IMPROVED PROCESS FOR DESTROYING THE PUTRESCIBLE MATTER OF HOUSE OR TOWN SEWAGE, SEPARATING THE SOLID MATTER, AND FOR OBTAINING AMMONIA FROM SUCH SEWAGE
Year: 1881

page_text: LETTERS PATENT to John Boyd Kinnear, of 9, Old Square, Lincoln's Inn,
in the County of Middlesex, Barrister-at-Law, for an Invention of "AN
IMPROVED PROCESS FOR DESTROYING THE PUTRESCIBLE MATTER OF HOUSE
OR TOWN SEWAGE, SEPARATING THE SOLID MATTER, AND FOR OBTAINING
AMMONIA FROM SUCH SEWAGE."
PROVISIONAL SPECIFICATION left by the said John Boyd Kinnear at the
Office of the Commissioners of Patents on the 19th October 1881.
JOHN BOYD KINNEAR, of 9, Old Square, Lincoln's Inn, in the County of
Middlesex, Barrister at Law. "AN IMPROVED PROCESS FOR DESTROYING THE
PUTRESCIBLE MATTER OF HOUSE OR TOWN SEWAGE, SEPARATING THE SOLID
MATTER, AND FOR OBTAINING AMMONIA FROM SUCH SEWAGE."
The sewage is run into covered tanks which must not be quite filled. During the
filling or afterwards it is mixed with quick lime or other alkaline matter, in
proportions varying according to the nature and strength of the sewage, a larger
quantity being required where there is much feculent matter. As a general rule
from 10 to 20 grains of quick lime, or a chemically equivalent quantity of other
alkaline matter is required, and sufficient for one gallon of ordinary sewage of
towns, but an excess of lime or alkaline matter is not injurious, and a deficiency
only renders the process less complete. Heat is applied to the sewage either before
or after the mixing, but in any case it is continued for some time after the mixing
and the reception of the sewage in the tanks. It may be applied either directly
to the exterior of the tanks, or by means of pipes passing through them, heated by
hot water or steam, or by injecting hot air, hot water, or steam, or in any other
convenient way. The temperature may be raised to the boiling point, and the
higher the temperature to which the sewage is raised the shorter is the time
necessary, but lower temperatures suffice in a longer time, and at from 120° to 130°;

page_text: the process generally requires about 10 hours of application of the heat. The
nitrogenous compounds existing in the sewage are by this process in great part
decomposed, and the nitrogen converted into ammonia, and the ammonia so formed,
as well as that already existing in the sewage, is expelled from the liquid in a
gaseous form. The expulsion is more rapid in proportion to the extent of surface
of the liquid, and it may be aided by passing air through it. The ammoniacal gas
may be absorbed in dilute sulphuric or other acid contained in troughs, trays, or
other vessels placed in the tanks over the sewage, or made to fall in drops or spray
into such vessels, or otherwise arranged so as to present large surfaces for
absorption, or the air over the sewage may be drawn off and the ammonia con-
densed or combined by passing it through water or acids, or through scrubbers as
in use in gas works, or in any other convenient way. When the evolution of the
ammonia from the sewage is sufficiently complete the heat is to be discontinued,
when the solid matter of the sewage will quickly subside, leaving the supernatant
liquid nearly or quite clear and free from putrefactive matter. If desirable to free
it from lime, this may be effected by passing through it a current of carbonic acid
gas from a furnace or other source, when the lime will be precipitated as carbonate.
The clear liquid may be run off and the solid deposit collected, or a fresh quantity
of sewage may be introduced into the tank and similarly operated on in succession,
till a sufficient quantity of solid matter has accumulated at the bottom of the tank
to require removal, and such solid matter being removed may be dried by the
waste heat of the furnace or tanks, and if desired, may be calcined and used again
for mixing with fresh sewage.
What I claim as my Invention in the process above described is the application
of heat to house or town sewage when mixed with lime or other alkaline matter,
for the purpose of destroying the putrescible matter, separating the solid matter,
and obtaining ammonia from the sewage.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Boyd Kinnear in the Great Seal Patent Office on the
17th April 1882.
JOHN BOYD KINNEAR, of 9, Old Square, Lincoln's Inn, in the County of
Middlesex, Barrister at Law. "AN IMPROVED PROCESS FOR DESTROYING THE
PUTRESCIBLE MATTER OF HOUSE OR TOWN SEWAGE, SEPARATING THE SOLID
MATTER, AND FOR OBTAINING AMMONIA FROM SUCH SEWAGE."
.
The sewage is run into covered tanks which must not be quite filled. During
the filling or afterwards it is mixed with quick lime or other alkaline matter, in
proportions varying according to the nature and strength of the sewage, a larger
quantity being required where there is much feculent matter. As a general rule
from 10 to 20 grains of quick lime, or a chemically equivalent quantity of other
alkaline matter is required, and sufficient for one gallon of ordinary sewage of
towns containing from 5 to 10 grains of combined nitrogen, but an excess of lime
or alkaline matter is not injurious, and a deficiency only renders the process less
complete. Heat is applied to the sewage either before or after the mixing, but in
any case it is continued for some time after the mixing and the reception of the
sewage in the tanks. It may be applied either directly to the exterior of the
tanks, or by means of pipes passing through them, heated by hot water or steam,
or by injecting hot air, hot water, or steam, or by injecting hot air, hot
water, or steam, or in any other convenient way. The temperature may be
raised to the boiling point, and the higher the temperature to which the
sewage is raised the shorter is the time necessary, but lower temperatures suffice
in a longer time, and at from 120° to 140° Fahrenheit; the process generally
requires about ten hours of application of the heat. The nitrogenous compounds
existing in the sewage are by this process in great part decomposed, and the
nitrogen converted into ammonia, and the ammonia so formed, as well as that
already existing in the sewage, is expelled from the liquid in a gaseous form. The
expulsion is more rapid in proportion to the extent of surface presented by the
liquid, and such surface may be increased by passing air through the liquid, or by
forcing it into the air in the form of spray or drops. The ammoniacal gas given
off from the hot liquid may be absorbed in dilute, sulphuric, or other acid contained
in troughs, trays, or other vessels placed in the tank over the sewage, or made to
fall in drops or spray into such vessels, or otherwise arranged so as to present large
surfaces for absorption, or the air over the sewage may be drawn off, and the
ammonia condensed or combined by passing it through water or acids, or through
scrubbers, as in use in gas works, or in any other convenient way. When the
decomposition of the nitrogenous or putrescible matter is sufficiently complete, which
may be generally known by the solid matter becoming of a lighter colour, and
ceasing to show bubbles of gas, and when the evolution of ammonia is carried as far
as can be done to profit the heat is to be discontinued, when the solid matter of the
sewage will quickly subside, leaving the supernatant liquid nearly or quite clear
and free from putrefactive matter. If desirable to free it from lime, this may be
effected by passing through it a current of carbonic acid gas from a furnace or
other source, when the lime will be precipitated as carbonate. The clear liquid
may be run off and the solid deposit collected, or a fresh quantity of sewage may
be introduced into the tank and similarly operated on in succession, till a sufficient
quantity of solid matter has accumulated at the bottom of the tank to require
removal, and such solid matter being removed may be dried by the waste heat of
the furnace or tanks, and if desired may be calcined and used again for mixing

page_text: with fresh sewage. The waste heat of the purified sewage may otherwise be used
to raise the temperature of the next quantity of sewage to be operated on.
What I claim as my Invention in the process above described is,-
The application of heat to house or town sewage when mixed with lime or other
alkaline matter, for the purpose of destroying the putrescible matter, separating the
solid matter, and if desired, obtaining ammonia from the sewage.
In witness whereof, I, the said John Boyd Kinnear, have hereunto set my
hand and seal, this Fifteenth day of April, in the year of our Lord One
thousand eight hundred and eighty two.
T ROVD KINNEAR
I BOVD KINNEAR (I.S.)