AN IMPROVED PROCESS AND APPARATUS FOR PURIFYING OR DISINFECTING SEWAGE
Year: 1881

page_text: LETTERS PATENT to Friedrich Petri, Doctor of Philosophy, of Berlin, Prussia,
German Empire, for an Invention of "AN IMPROVED PROCESS AND APPARATUS
FOR PURIFYING OR DISINFECTING SEWAGE."
PROVISIONAL SPECIFICATION left by the said Friedrich Petri at the Office of
the Commissioners of Patents on the 9th December 1881.
FRIEDRICH PETRI, Doctor of Philosophy, of Berlin, Prussia, German Empire.
"AN IMPROVED PROCESS AND APPARATUS FOR PURIFYING OR DISINFECTING
SEWAGE."
My Invention relates to an improved process and apparatus for disinfecting or
purifying sewage.
Sewage which cannot or should not be used for the irrigation of land is well
known on account of the organic mixtures, the fecal matters; and other refuse it
contains to have a noxious influence upon the rivers, lakes, or other waters into
which it flows. It is also known that sewage, which through previous ground
infiltration, by means of irrigation, has been deprived of the greater part of its
orgauic admixture, is (even when the land presents the most favorable condition)
still detrimental to health, so that its discharge into waters which are in the neigh-
bourhood of dwelling places should not be effected without serious consideration.
Moreover, during the frost in winter there is a long period of inactivity for the
irrigation canals as regards ground infiltration, which causes an accumulation of
the sewage in basins built at great cost, from which exhalations detrimental to
health are spread far and wide.
This Invention is designed to provide means for chemically and mechanically
purifying sewage without ground infiltration, and in a simple and economical
manner, so that the discharged water or liquor may without danger be led into
rivers, lakes, or other waters.
My Invention is carried into practice in the following manner, that is to
say:
4
The sewage laden with refuse is conducted by means of a pipe into a basin, in

page_text: which it is caused to pass through a bed made of absorbing material, and covered
with disinfectants. The water or liquor which flows from this basin, though already
clear, contains still in small quantities organic constituents, which I destroy by
means of appropriate quantities of acids and chlorides, and the possible excess of
which I neutralize by means of chalk, through which the water has to pass before
its ultimate discharge. For greater security before the water or liquor is discharged
into the river, lake, or other water, it may be made to pass through a bed of coarse
sand so as to clear it from whatever chalk it may have carried with it.
The process is based upon the following features, that is to say :-
The use of a filtering bed, the adjustment of which regulates the flow of water,
and which is so constructed that in case of continuous work, while one part thereof
is in activity the other part is dry, the contents being appropriate to the absorption
of the noxious matters.
The use of an absorbing mass wherewith the basins are filled, and the means
employed to prevent the exhalations from being detrimental to health.
The means employed for the destruction of the organic constituents, and for the
removal of the excess of the same.
According to my Invention I am enabled to completely purify the sewage of
towns.or of several dwellings in close proximity to one another in an economical
manner before it is discharged into streams or other waters.
By employing a filtering bed of sufficiently large dimensions I can, by my
Invention, easily purify 1,000 cubic meters of sewage per day without requiring to
renew the absorbing material more frequently than three or four times a year.
Two such filtering beds placed close to each other may be so connected by means
of valve arrangements that the one or the other may in turn be used while the
other is emptied.
The size of the bed will be determined by local circumstances, the configuration
of the ground, the fall, and the mass of sewage and its consistency.
In
In constructing the filtering apparatus I provide a supply pipe which conducts
the sewage into the apparatus; also a gutter which receives the water or liquors.
from this pipe and conducts it to the basins on both sides; also open work, which
may consist of perforated masonry or of gratings of wood or iron, through which
the sewage reaches the basius, and which prevents the passage of coarse substances
such as rags, paper, shavings, or the like. Basins are placed one on each side of
the gutter, or there may be one basin only provided it is sufficiently large.
these basins rests the bed of absorbing material which effects the mechanical
purification and partially the chemical purification. For these basins I prefer the
rhombus form, because it is suitable for the flow of the water; but they may have
any other suitable form. They are constructed of masonry or concrete in such a
manner that no portion of the unclean sewage can pass through the same either
at the bottom or sides.
The basins are provided on one side with a layer of bundles of brush wood mixed
with coarse sand, in which certain matters which the water would otherwise carry
away in passing through the absorbing materials will be retained. I also provide
diaphragms consisting of sieves or of metal wires, or gauze drawn tight across
frames, which are also designed to hold back or detain the fine mechanical
adimixtures which are still contained in the liquor after the same has passed
through the layer of bundles and sand. For greater security several diaphragms
can thus be arranged behind one another in order to be able to clean them in turns.
I also provide gutters through which the water thus treated flows to a basin
mentioned hereinafter.
:
I also provide an apparatus to be used for the introduction of acids or chlorides, or
both, into the liquor in order to destroy the small quantities of organic matters
which are still in the same. They must be either dripping or suction
apparatuses.
I provide a basin which is filled with basic substances, as for example limestone,
rubble, chalk, marble, or the like, in order to neutralize the possible excess of acids

page_text: or chlorides which have been added to the water. In this basin there is a division
filled with coarse sand or gravel by which the particles of chalk still in the liquor
are held back.
From this basin the liquor is discharged thoroughly cleansed through an
outlet.
For the absorbing mass I employ pervious porous materials which consist of
vegetable materials, as, for example, turf rubbish, charcoal rubbish, small coal,
sawdust, and the like, which by reason of their well known capability of inter-
cepting matter in decomposition cause the same to be changed into innoxious
substances insoluble in water.
When especially thick sewage has to be dealt with, such substances as provide
at the same time antiseptic and filtering media may be added. Such substances
are, for example, gypsum, chalk, or bone black, which, even should there remain
traces of them in the water or liquor when discharged, are not detrimental to the
fish or other living creatures in rivers or the like, and cannot therefore be
injurious.
I
To prevent the filtering mass from getting foul through being supersaturated
with refuse under the influence of the air, especially during the warmer season,
cover the absorption hed with a layer of small pieces of turf which have been
soaked beforehand with a solution of carbolic or salicylic acid, and then dried, so
that the pores remain impregnated with the acids. Over these I spread a second
layer, which consists of potassium bisulfphate, to which is added some substance
pervious to the air, such as leaves, shavings, or chaft.
The layers must be placed at such a height that the water which flows through
does not reach them, and thus prevent their lixiviation. Their purpose is to shelter
the absorption mass from the fermentation which would be produced by the air,
and thus prevent its fouling, and also to combine with the small quantity of
ammonia which is formed.
Therefore at the time of laying the filter the absorbing mass must be built up
comparatively high, so that the water will always flow only through the lower
part of the same.
The water coming out of the filtering basin flows through the gutters, and is on
its way subjected to a further treatment.
I have found that the organic admixtures which remain in the sewage after the
foregoing process, although they can easily be traced by the qualitative analysis,
only very small traces can be detected, so that a comparatively small quantity of
acid is needed to destroy them all.
For that purpose I use sulphuric or hydrochloric acid, the latter in preference,
on account of its cheapness, which I conduct to the water by means of a dripping
or suction apparatus. These apparatus consist of vessels with pipes, which are
brought over or by the side of the gutters. Either the acid drips direct into the
gutter, or a fine pipe dips in the water bent in the direction of the stream, so that
through it suction takes place. The quantity required can be easily regulated by
the insertion of a cock in the efflux pipe. The vessels and pipes of these apparatuses
are made of such materials as will resist the action of the acids, viz., glass or
hardened india rubber.
For the same purpose I use, besides the acid chlorides such for example as
ethylic or trimethylic chlorides, or other chlorides of alcohol.
For the better distribution of the small quantities of the acid or of the chloride
a stirring apparatus is arranged in the gutter, and is set and kept in motion either
by means of the flow of the water itself, or by means of a weight.
When the addition of the acids or chlorides attains a maximum of 5 grammes
per cubic meter of running water a complete destruction of the organic elements
of the water takes place. After the neutralization of the acid has taken place in
the basin filled with chalk through which the liquor is forced to pass, and the
few chalk compounds which were carried away have been detained by the gravel,

page_text: the water or liquid runs away clear and free from all substances detrimental to
health.
By the process herein described with the aid of the said filtering bed the
utilization of sewage without irrigation fields will become possible, and thus town
refuse will be available as manure for agricultural purposes.
When the filtering
ability of the bed becomes perceptibly weak the sewage is led into the neighbouring
basin, and the one hitherto used is emptied in order to replenish it with fresh
material. The protecting layers are raised carefully before the emptying takes
place, and can again be used. The turf rubbish laden with the solid particles of
fecal matter left behind can, after it has been dried in the air, easily be transported
to be utilized as manure.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Friedrich Petri in the Great Seal Patent Offico on the 6th June
1882.
FRIEDRICH PETRI, Doctor of Philosophy, of Berlin, Prussia, German Empire.
'AN IMPROVED PROCESS AND APPARATUS FOR PURIFYING OR DISINFECTING
SEWAGE."
My Invention relates to an improved process and apparatus for disinfecting or
purifying sewage.
Sewage which cannot or should not be used for the irrigation of land is well
known on account of the organic mixtures, the fecal matters and other refuse it
contains to have a noxious influence upon the rivers, lakes, or other waters into
which it flows. It is also known that sewage which through previous ground
infiltration by means of irrigation has been deprived of the greater part of its
organic admixtures is (even when the land presents the most favorable conditions)
still detrimental to health, so that its dischargo into waters which are in the
neighbourhood of dwelling places should not be effected without serious con-
sideration. Moreover during the frosts in winter there is a long period of
inactivity for the irrigation canals as regards ground infiltration, which causes
an accumulation of the sewage in basins built at a great cost, from which
exhalations detrimental to health are spread far and wide.
This Invention is designed to provide means for chemically and mechanically
purifying sewage without ground infiltration and in a simple and economical
manner, so that the discharged water or liquor may without danger be led into
rivers, lakes, or other waters.
My Invention is carried into practice in the following manner, that is to say :-
The sewage laden with refuse is conducted by means of a pipe into a basin, in
which it is caused to pass through a bed made of absorbing material and covered
with disinfectants. The water or liquor which flows through this basin, though
already clear, still contains in small quantities organic constituents, which I destroy
by means of appropriate quantities of acids and chlorides, the possible excess of
which I neutralize by means of chalk through which the water has to pass before
its ultimate discharge. For greater security before the water or liquor is discharged'
into the river, lake, or other water, it may be made to pass through a bed of coarse
sand so as to clear it from whatever chalk it may have carried with it.
The process is carried on, as hereinafter described, and by the following means,
that is to say-The use of a filtering bed, the adjustment of which regulates the
flow of water, and which is so constructed that in case of continuous work while
one part thereof is in activity, the other part is dry, the contents being appropriate
to the absorption of the noxious matters.
The use of an absorbing mass wherewith the basins are filled and the means
employed to prevent the exhalations from being detrimental to health, the
destruction of the organic constituents, and the neutralization of the excess of
acids or other materials employed for that purpose.
According to my Invention I am enabled to completely purify the sewage of
towns or of several dwellings in close proximity to one another in an economical
manner before it is discharged into streams or other waters.
In the accompanying Drawing is shown a filtering bed and apparatus which I
employ in carrying on the improved process. By employing filtering beds of
sufficiently large dimensions, I can by my Invention easily purify 1000 cubic metres
of sewage per day without requiring to renew the absorbing material more

page_text: frequently than three or four times a year. Two such filtering beds placed close
to each other may be so connected by means of valve arrangements that either
one may in turn be used while the other is emptied, but only one bed is shown in
the Drawing. The size of the bed will be determined by local circumstances, the
configuration of the ground, the fall, the mass of sewage and its consistency, and
the form of the bed may be different from that shown in the Drawing if desired.
In constructing the filtering apparatus I provide a supply pipe a which conducts
the sewage into the apparatus; also a gutter b which receives the water or liquid
from this pipe and conducts it to the basins d, d, on both sides; also open work
c, c', which may consist of perforated masonry or of gratings of wood or iron
through which the sewage reaches the basins, and which prevents the passage of
coarse substances, such as rags, paper, shavings, or the like. The basins d, d', are
placed one on each side of the gutter b, or there may be one basin only, provided it is
Bufficiently large. In these basins rests the bed of the absorbing material m which
effects the mechanical purification and partially the chemical purification. For
these basins I prefer the rhombus form because it is suitable for the flow of tho
water, but they may have any other suitable form. They are constructed of
masonry or concrete, in such a manner that no portion of the unpurified sewage
can pass through the same either at the bottom or sides, and the basins d, d', are
provided on one-side-with-a-layer_of_bundles_of_brushwood mixed with coarse
sand, in which certain matters which the water would otherwise carry away in
passing through the absorbing materials will be retained.
I also provide diaphragms f, f¹, consisting of sieves formed of metal wires or
gauze stretched tightly across frames, and designed to hold back or detain the fine
mechanical admixtures which are still contained in the liquor after the same has
passed through the layer of bundles and sand. For greater security several
diaphragms can thus be arranged one behind another in order to be able to clean
them in turns. I also provide gutters g, gl, through which the sewage water thus
treated flows to a basin mentioned hereinafter. I also provide an apparatus h, h',
to be used for the introduction of acids or chlorides, or both, into the liquor in
order to destroy the small quantities of organic matters which are still in the same.
These should be either dripping or suction apparatuses, as shewn in Figures 5
and 6; and I provide a basin i which is filled with basic substances, as, for
example, limestone, rubble, cbalk, marble, or the like, in order to neutralize the
possible excess of the acids or chlorides which have been added to the water. In
this basin is a compartment & filled with coarse sand or gravel by which the
particles of chalk still in the liquor are held back. From this basin the liquor is
discharged thoroughly cleansed through an outlet l.
For the absorbing mass m I employ pervious porous materials, consisting of
vegetable matter (such as refuse turf), charcoal, small coal, saw dust, or the like,
which, by reason of their well known capability of intercepting matter in
decomposition, cause the same to be changed into innoxious substances insoluble in
water.
When especially thick sewage has to be dealt with substances which provide at
the same time antiseptic and filtering media may be added. Such substances
are, for example, gypsum, chalk, or bone black, which even should there remain
traces of them in the water or liquor when discharged are not detrimental to the
fish or other living creatures in the rivers or the like, and cannot therefore be
injurious.
To prevent the filtering mass from getting foul through being supersaturated
with refuse under the influence of the air, especially during the warmer season,
I cover the absorption bed with a layer of small pieces of turf which have been
soaked beforehand with a solution of 2 parts carbolic or salicylic acid in 100 parts
water, and then dried, so that the pores remain impregnated with the acids. Over
these I spread a second layer o, o', which consists of bisulphate of potash, to which
is added some substance pervious to the air, such as leaves, shavings, or chaff. The
layers n and o must be placed at such a height that the water which flows through

page_text: "
does not reach them and thus prevent their lixiviation. Their purpose is to
protect the "absorbing mass from the fermentation which would be produced by
the action of the air and thus prevent its fouling, and also to combine with the
small quantity of ammonia which is evolved. Therefore at the time of laying
the filter the absorbing mass m must be built up comparatively high, so that the
water will always flow only through the lower part of the same.
The water coming out of the filtering basin flows through the gutters g, g¹, and
is subjected during its passage to further treatment. I have found that, although
the organic admixtures which remain in the sewage after the foregoing process can
easily be traced by the qualitative analysis, only very small traces can be detected,
so that a comparatively small quantity of acid is required to destroy them all.
For this purpose I use sulphuric or hydrochloric acid (the latter by preference on
account of its cheapness), which I conduct to the water by means of dripping or
suction apparatuses h, h². These apparatuses consist of vessels with discharge
pipes, which are brought over or by the side of the gutters. Either the acid drips
directly into the gutter, as shown at I in Figure 6, or a small pipe dips into the
water and is bent in the direction of the stream, as shown at 2 in Figure 6, so
that through it the suction takes place. The quantity required can be easily
regulated by the insertion of a cock in the discharge pipe. The vessels and pipes
of these apparatuses are made of such materials as will resist the action of the
acids, such as glass or hardened india-rubber.
For the same purpose I use, besides the acid or without them, chlorides, such for
example as chloride of ethyl or trimethyl, or other chlorides of alcohol.
For the better distribution of the acid, or of the chloride, stirring devices p, p¹,
may be employed in the gutters and kept in motion either by means of the flow of
water itself or by means of a weight.
When the addition of the acids or chlorides attains a maximum of 5 grammes
per cubic metre of running water a complete destruction of the organic elements
contained in the water is effected. After the neutralization of the acid has taken
place in the basin i, filled with chalk, through which the liquor is forced to pass,
and the few chalk compounds which were carried away have been detained by the
gravel, the water or liquid flows away clear and free from all substances detrimental
to health.
By the process herein before described, with the aid of the said filtering bed, the
utilization of sewage without irrigation fields will become possible, and thus town
refuse will be available as manure for agricultural purposes. When the filtering
capacity of the bed m becomes perceptibly weak the sewage is led into the
neighbouring basin, and the one previously used is emptied in order to replenish it
with fresh material. The protecting layers n, n', and o, o¹, are raised carefully
before the emptying takes place and can again be used. The refuse turf laden with
the solid particles of fecal matter left behind can after it has been dried in the air
easily be transported to be utilized as manure. .
Having thus fully described my said Invention, and the manner of performing
the same,
wish it understood that I claim,-
First. The process of chemically and mechanically purifying sewage to enable it
to be discharged into rivers, lakes, or the like, without danger to health, the said
process consisting in first passing the sewage through a bed of filtering material,
either horizontal or inclined, and composed of the absorbing mass m covered with
the layers n, o, then passing the sewage through gravel and wire gauze, or the
like, mixing it with acids or chlorides, or both, to destroy any organic matter still
contained in it, then passing it through chalk or the like to neutralize any excess
of acid, and finally through a bed of gravel, all substantially as and for the purposes
set forth.
Second. The filtering apparatus for the purification of sewage, consisting in a
basin in which the sewage passes through a coarse grating, or through perforated
masonry, and through a bed of filtering material, and then through a layer of
gravel, which clears it of its fine mechanical admixtures, in combination with an

page_text: outlet gutter and a basin containing lime, rubble, or marble, and provided with
a compartment filled with gravel, all substantially as and for the purposes set
forth.
Third. The filtering bed, consisting of a mass of refuse turf, charcoal, or sawdust,
of such height that the water only passes through its lower part, the said mass
being covered with two layers, one consisting of turf soaked with a solution of
carbolic or salicylic acid and dried, and having spread over it the other layer,
consisting of bisulphate of potash mixed with substances pervious to air,
such as shavings, chaff, leaves, or tho like, substantially as and for the purposes
set forth.
Fourth. In combination with the filtering bed, the dripping or suction apparatus
for the introduction of the acids or chlorides into the water or liquor, and the
stirring apparatus for mixing the same, substantially as set forth.
In witness whereof, I, the said Friedrich Petri, have hereunto set my hand
and seal, this Third day of June, in the year of our Lord One thousand
eight hundred and eighty two.