IMPROVEMENTS IN THE TREATMENT OF SEWAGE AND OTHER WATERS FOR THE PURPOSE OF PURIFYING THE SAME
Year: 1878

page_text: LETTERS PATENT to Walter East, of Kingston-on-Thames, in the County of
Surrey, for the Invention of "IMPROVEMENTS IN THE TREATMENT OF SEWAGE
AND OTHER WATERS FOR THE PURPOSE OF PURIFYING THE SAME."
Sealed the 13th June 1878, and dated the 7th January 1878.
PROVISIONAL SPECIFICATION left by the said Walter East at the Office of
the Commissioners of Patents on the 7th January 1878.
WALTER EAST, of Kingston-on-Thames, in the County of Surrey.
"IMPROVE-
MENTS IN THE TREATMENT OF SEWAGE AND OTHER WATERS FOR THE PURPOSE OF
PURIFYING THE SAME."
This Invention has for its object improvements in the treatment of sewage and
other waters for the purpose of purifying the same.
The foul odour given off by sewage arises from the liberation of sulphuretted
hydrogen and other gases during the process of fermentation.
According to my Invention I purify the sewage by retaining it in a covered tank,
and whilst it is there I hasten the fermentation by adding to it a ferment con-
taining suitable germs, for example, other sewage in a state of active fermentation,
and I maintain the sewage as nearly as may be convenient at the temperature at
which fermentation goes on most rapidly. By preference, the temperature should
not be allowed to fall below 60 degrees, or to rise above 80 degrees. The gases
liberated are led away by pipes and utilised or destroyed, or they may be liberated
in a situation where they will not cause nuisance.
When the fermentation is complete, some free sulphuretted hydrogen will remain
in solution, and this I get rid of by the addition of oxide of iron, or the same result
may be obtained in other ways.
Other foul waters may be similarly purified, and the process is applicable where
the amount of impurity is but small, as for example, for the treatment of river
water to render it suitable for the supply of towns.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Walter East in the Great Seal Patent Office on the 6th July
1878.
WALTER EAST, of Kingston-on-Thames, in the County of Surrey. "IMPROVE-
MENTS IN THE TREATMENT OF SEWAGE AND OTHER WATERS FOR THE PURPOSE OF
PURIFYING THE SAME."
This Invention has for its object improvements in the treatment of sewage and
other waters for the purpose of purifying the same.
The foul odour given off by sewage arises from the liberation of sulphuretted
bydrogen and other gases during the process of fermentation or putrefaction.
According to my Invention I purify the sewage by retaining it in a covered tank,
and whilst it is there I hasten the fermentation or putrefaction by adding to it a
ferment containing suitable germs, for example, other sewage in a state of active
fermentation, and I maintain the sewage as nearly as may be convenient at the
temperature at which fermentation or putrefaction goes on most rapidly. By
preference the temperature should not be allowed to fall below 60 degrees, or to
rise above 80 degrees. The gases liberated are led away by pipes and utilized or
destroyed, or they may be liberated in a situation where they will not cause
nuisance.
When the fermentation or putrefaction is complete, some free sulphuretted
hydrogen will remain in solution, and this I get rid of by the addition of oxide of
iron, or the same result may be obtained in other ways.
Other foul waters may be similarly purified, and the process is applicable where
the amount of impurity is but small, as for example, for the treatment of river
water to render it suitable for the supply of towns.
In order that my said Invention may be most fully understood and readily
carried into effect, I will proceed to describe the method in which I prefer to
operate when treating sewage, such as is commonly met with in small towns, as it
is in such places that the use of my Invention is especially advantageous.
I provide a number of tanks, each of a capacity to receive a day's sewage or
somewhat more; ten such tanks will be a fully sufficient number in most cases.
The tanks are covered so that gases generated within them can only escape by a
channel provided for the purpose, and which leads them into contact with hydrated
oxide of iron contained in purifiers similar to those in use at gasworks for the
separation of sulphuretted hydrogen from coal gas.
To draw off the gas from the tanks and to cause it to be replaced by air entering
by an aperture provided for the purpose, I conduct a small flue from the purifier to
the ash-pit of a furnace.
I fit the inlet aperture with a self-acting valve to prevent escape of gas.
Where it is necessary to pump the sewage, the furnace employed will be that by
which the steam boilers are heated.
In other cases I provide a furnace to maintain a slow current of air sufficient to
effect a gradual change of the gaseous contents of the tanks.
Any sulphuretted hydrogen gas which may escape decomposition by the oxide
of iron will be burnt in its passage through the fire to the chimney, and so all risk
of nuisance is avoided. Passage through fire also destroys any germs carried in
the gases.
In starting the process I draw into the tank from one of the adjacent tanks a
quantity of sewage already in a state of active fermentation or putrefaction. I take
care as far as possible to employ for this purpose the sewage, which appears to be
most heavily loaded with the germs of putrefaction. These germs are generally
found in greatest number within a few inches of the surface of the sewage in the
fermenting or putrefying tanks. I then proceed to fill the tank, adding to the
fermenting or putrefying sewage three or four times its bulk of fresh sewage.

page_text: Usually the sewage will be drawn from the sewers at a temperature favourable to
fermentation or putrefaction, but should this not be the case I cause the temperature
to be raised to a point which is suitable by blowing steam into the tank. Fer-
mentation or putrefaction rapidly sets in, and continues until all the matters
capable of putrefying are destroyed. Much depends upon circumstances, but these
being favorable, a week should fully suffice to complete the operation.
Towards the end of the operation I force air through the liquid in the tank by
means of pipes dipping down into it, and which are in connection with an air
pump or other apparatus for forcing air. In this way any gases resulting from the
decomposition, and which may be in solution in the liquid, are separated and carried
through the fire. When the liquid has become odourless or nearly so, I draw
it off from the tank through filters, consisting of sand and oxide of iron, and then
the water, which flows from the filters, will be found sufficiently puro for any
purpose of irrigation or admission to streams.
Any deposit remaining in the tank is innoxious, and may be removed when it
has accumulated to an extent to render this necessary.
The oxide of iron when charged with sulphur can be revivified by exposure to
air, and when the sulphur has accumulated to an extent to interfere with the
action of the oxide, it may be utilized by well-known processes.
What I claim is the treatment of sewage and other waters, in the manner sub-
stantially as described, fermentation or putrefaction of the water or matter being
promoted and hastened whilst it is contained in a tank or vessel, so arranged as to
prevent the escape of the gaseous products of decomposition where a nuisance would
be caused.
In witness whereof, I, the said Walter East, have hereunto set my hand and
seal, this Fifth day of July, in the year of our Lord One thousand eight
hundred and seventy-eight.
WALTER EAST. (LS.)