Improvements in the Purification and Utilisation of Sewage and Apparatus therefor.
Year: 1886

page_text: Date of Application, 25th Mar., 1886.
Complete Left, 21st Dec., 1886.
Complete Accepted, 8th Mar., 1887.
Improvements in the Purification and Utilisation of Sewage
and Apparatus therefor.
I, LOUIS GUSTAVE GHILAIN DAUDENART of Brussels in the Kingdom of Belgium,
Inventor, do hereby declare the nature of this invention to be as follows:-
The utilization of sewage is an economical problem interesting both hygienically
and agriculturally, and one that from both these points of view, has not yet received a
satisfactory solution. It is now well recognized that irrigation applied to well
mellowed land constitutes the true, the sole practical means of purifying sewage, by
transforming the organic nitrogen that it contains into ammonia, or into nitrates.
Nevertheless the immediate irrigation of sewage is impracticable for large towns
because, generally in their neighbourhood there cannot be found large spaces of little
value, which an extensive application of sewage to agriculture requires. In such cases
the question is complicated owing to difficulty of transport of the sewage to a distance
often necessitating its elevation to considerable heights. This transport could not be
effected uncovered (of this there is no need of demonstration) and if, for sanitary
reasons hermetically closed conduits be made use of the costs of such an undertaking
would obviously render it unprofitable.
Moreover, whilst admitting (as experience seems to indicate) that the foetid
emanations, which the sewage disengages, when distributed on the ground may be
rapidly enough destroyed as not to be injurious to public health, it is impossible to
prevent the efflux of factory drainage into the drains, which waters, mingle with the
sewage properly so called often introducing substances detrimental to the agricultural
products.
.
These preliminaries admitted, we propose to give hereafter a general solution
of the question so much agitated of the utilization of sewage for agriculture.
Admitting that by means of a chemical process, simple in its application and
inexpensive the sewage has been converted into a clear, limpid, inodorous and
inoffensive liquid, without having lost its fertilizing properties. It is obvious that the
transport in the open air of such a liquid would not in any manner be injurious to
public health, and that the question of transport of the sewage to long distances

page_text: what affers can
gut soms a remedy mау
be found for the open air transport of the sewage, covering the country to be fertilized
with a network of irrigating canals constituting in its entirety a system of navigable
ways receiving their waters from those of the transport canal itself, that is to say from
the sewage.
Such is in a few words the outline of my system for the agricultural utilization of
sewage. My system has consequently the following characteristics. A. Chemical
purification of sewage transforming its contagious and unsanitary waters into a clear,
limpid, inodorous and inoffensive liquid. B. Employment of an open air transport
canal for the sewage, which canal receives the sewage itself. C. Employment of a
mode of irrigation supplying the country to be fertilized with manure, water and
communications that are absolutely or relatively wanting to it.
I will now further describe these three essential parts of our system.
A. CHEMICAL PURIFICATION.
I find that the use of metallic salts and preferably of the soluble salts of zinc, is
indispensable in order to economically effect the removal from the sewage of substances
prejudicial to vegetation. This employment nevertheless presents a danger, that it is
necessary to know how to avoid. When in practice one treats the sewage with a
soluble salt of zinc, the free carbonic acid that the sewage contains, in addition to that
which the reaction sets free, dissolves a part of the oxide of zinc which, besides causing
loss of the re-agent introduces into the liquid a salt injurious to vegetation. It is
important then to fix beforehand this carbonic acid; slaked lime is the most economical
re-agent for this. The sewage is therefore treated first of all with a quantity of lime
so that after the transformation into carbonate of lime which is precipitated, the liquid
shows a slight alkaline re-action. The lime also produces a partial purification by
precipitating the organic matters suspended in the liquid, this effect is well known and has
been already utilized. The alkalinity of the liquid produced by the lime thus assures the
efficaciousness of the treatment by a soluble salt of zinc. The separation of the
precipitate being effected the liquid slightly opalescent and still odoriferous, is treated
with a mixture of sulphate of alumina and of chloride of zinc. The salt of alumina
causes the precipitation of organic matters still capable of being precipitated, and the
zinc salt destroys in the deodorized liquid the sulphuretted hydrogen compounds which
the salt of alumina has not been able to reduce. The result of this re-action is an
organic salt precipitate which is separated, by the filter, from the liquid which now
appears transparent and limpid exhaling no odour and being besides inoffensive. The
precipitate is carefully collected and slightly calcined in closed chambers. On cooling,
it appears in the form of a carbon which contains the alumina and the sulphuret of
zinc resulting from the re-action. This carbon is treated with an acid (sulphuric or
hydrochloric) which reproduces the soluble salts of alumina and of zinc, to be again
employed in a subsequent purification.
This mode of purification is distinguished from all similar processes by this
peculiarity that the action of the reagents employed, lime and sulphate of alumina, is
successive. This succession is a sine qua non condition of success. The lime
employed only precipitates the matters in suspension and a portion of the matters
dissolved, but it only very imperfectly removes the foetid odour, in fact it after a short
time increases it. The sulphate of alumina, employed alone, clears the liquid and destroys
the bad odour, but the voluminous and gelatinous precipitate which it causes, when
used alone renders the necessary filtration impracticable on a large scale. It is this
filtration which is the stumbling block to all purifying processes where salts of alumina
are employed as sole purifying re-agents. In treating, on the contrary the liquid
resulting from the action of the lime, with sulphate of alumina, a quantity of loose
organic matter is precipitated, which does not offer any obstacle to the filtration.

page_text: The separation of the organic matters precipitated by the lime, which easily collect,
owing to their relatively great density, is effected by aid of the apparatus hereafter
described. It consists of a large reservoir, at one end of which is an entrance drain,
and at the other end an exit drain. The dimensions of these three constituent parts of
the apparatus are so calculated that the speed of the sewage holding in suspension
the matters precipitated by the lime is slow enough, when passing through the
reservoir to cause them without stopping, to deposit the solid matters which are
collected and removed by means of an archimedian screw, and thus separated from the
liquid which runs off clear and limpid by the exit drain.
B. MODE OF TRANSPORT BY CANAL.
Apart from the novelty of its employment, from the peculiar character of its waters
and from the novel object that it is desired to attain, we have nothing to say from a
mechanical point of view of the canal in question. The construction is similar to any
other canal used for internal navigation and its dimensions necessarily depend on the
volume of waters which it has to carry, and the purposes for which it is designed.
I have said that the lime precipitates the matters in suspension which the sewage
contains as well as a part of the organic matters that it holds in solution. This
precipitate gathered in the form of liquid sediment expelled by the archimedian screw
may be freed from the water which serves as a vehicle and it would thus constitute a
manure equivalent to a good farm dung. But it is important to remark that
independently of the serious difficulties which the drainage of this precipitate,
suspended in thrice its weight of water, presents, its drainage in so far as manure, will
necessarily only be in a confined and relatively insufficient extent. The production,
besides, being incessant, obstruction would soon take place, and with it the grave
inconveniences that it carries along with it. It is besides desirable that these liquid
sediments be distributed on the soil to be fertilized in order to give it the degree of
porosity and lightness which constitutes the physical character of soils of the first
class. All these considerations have occupied us in effecting the transport of the
liquid sediments by means of a tube of iron or of masonry of 0.18 to 0.20 of
interior diameter, following the direction of the transport canal throughout its entire
length and which serves to distribute these sediments wherever necessary.
We will suppose in the following that the sewage will be distributed over a farm of
two hundred hectares, these forming a small part of the ground that would be
necessary to usefully absorb the sewage of a large centre of population. These 200
hectares form in their entirety a rectangular surface of 2000 metres long and
1,000 metres wide. This fixed, let this rectangle be divided into six equal parts
by 7 canals parallel to each other and to the long side of 2,000 metres, each canal
being of a section proportioned to the daily supply of sewage. These 7 canals are
also connected by two perpendicular canals of the same section which bound them
laterally and cause them to communicate with the irrigating canals of the fields.
The distance between the 2 consecutive and parallel canals is 161 metres and is
settled by the following considerations. A man, bearing a hose fixed at the extremity
of a flexible hose 20 metres in length will be able to irrigate by the jet from his hose,
the portion of the ground comprised in a width of 40 metres. A second man, also
supplied with a hose, 60 metres long will be able to irrigate a fresh width of
40 metres, so that, acting simultaneously, the two men will be able to irrigate an
extent of ground 80 metres wide; the respective hoses being supplied from the same
canal and from the same side of it. But from the other side of this canal, the same
arrangements being effected, a space of 160 inetres wide will thus be submitted to.
irrigation by hoses, that is to say a space equal to that which separates two canals.
If the hose be now moved according to the progress of the irrigation, in directions
always parallel to those of the canals, the irrigation will be able to cover each day the

page_text: 200 hectares constituting a farm. When the state of the fields under cultivation no
longer permits of motion parallel to the irrigating canals, then the workmen keep to
the fields perpendicular to these canals and employ exclusively the flexible hose of 60
metres long. Starting from opposite points of two consecutive canals, they walk
towards each other whilst irrigating on the same side, until they are only separated by
a distance of 40 metres. They then water in front of them as far as their hose will
carry, then returning to the points of departure they water during their return the
other side of the field. They then go to the following field, distant 40 metres from the
preceding one, and repeat the same operation. It will be seen from the calculation,
that in order to distribute the sewage in 24 hours over a farm of 200 hectares, 22 cubic
metres to the hectare, it is necessary to make use of a force of 20 horse power and to
employ 8 men carrying hose with nozzles 4 square centimetres in size. Now the
irrigating canals having a depth of one millemetre fifty and a width of 5 metres close
to the ground, they are consequently capable of supporting a pontoon, carrying an
engine of above 20 horse power, which pontoon, being towed by a man will slowly
traverse the canals with a speed suitable to the progress of the operation. Under
these conditions the persons required will be an engine driver, a tower
and 8 hosemen. Compared with the system of irrigation by hoses receiving water
from iron conduits, our system is distinguished by its extreme economy. But this
economy is the least of its advantages-In fact, each farm of 200 hectares thus
presenting 7 canals, each of 2000 metres length distant from one canal to the following
161 metres, and connected laterally by two canals of 1000 metres length, the country
to be fertilized will thus be covered with a network of navigable ways, which supply
it with the necessary water and manure. Besides all these canals communicating
with one another and ending, directly or indirectly, in the canal for the transport of
sewage, or with other large traffic ways of any kind-which they may meet with in
their course, the cultivator will be able to use them for the economic transport of his
agricultural produce. The great advantage of this system is that it transforms into
green fields land, which is now sterile owing to the absence of water, of manure and
above all of means of access-In certain cases, notably in the case of large extents of
valueless ground, the employment of hosemen may with advantage be done away
with, a great development being given, in place thereof, to the irrigating canals.
With this hypothesis, the interval between the consecutive parallel canals will be
80 metres in place of 160 metres, whilst augmenting the capacity of the hose to a
distance of 40 metres, the irrigation could be effected by means of hose fixed
immoveably at each side of the pontoon, inclined at the angle of 45 degrees and
capable of an automatic circular movement of up to 90 degrees and back again. In
this case the number of attendants will be reduced per farm to an engine man
superintending the hosemen, a fire man and a towing man.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool,
& 323, High Holborn, London,
Patent Agents for the Applicant.

page_text: I, LOUIS GUSTAVE GHILAIN DAUDENART of Brussels in the Kingdom of Belgium,
Inventor, 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:-
The utilization of sewage is an economical problem interesting both hygienically
and agriculturally, and one that from both these points of view, has not yet received a
satisfactory solution. It is now well recognised that irrigation applied to well
mellowed land constitutes the true, the sole practical means of purifying sewage, by
transforming the organic nitrogen that it contains into ammonia or into nitrates.
Nevertheless the immediate irrigation of sewage is impracticable for large towns
because generally, in their neighbourhood, there cannot be found large spaces of little
value, which an extensive application of sewage to agriculture requires. In such cases
the question is complicated, owing to the difficulty of transport of the sewage to a
distance often necessitating its elevation to considerable heights. This transport
could not be effected uncovered (of this there is no need of demonstration) and if, for
sanitary reasons, hermetically closed conduits be made use of, the costs of such an
undertaking would obviously render it unprofitable.
Moreover whilst admitting (as experience seems to indicate) that the foetid
einanations, which the sewage disengages when distributed on the ground nay be
rapidly enough destroyed, as not to be injurious to public health, it is impossible to
prevent the efflux of factory drainage into the drains, which waters mingle with the
sewage properly so called, often introducing substances detrimental to the agricultural
products.
These preliminaries admitted, we propose to give hereafter a general solution of the
question so much agitated, of the utilization of sewage for agriculture. Admitting
that by means of a chemical process, simple in its application and. inexpensive, the
sewage has been converted into a clear, limpid, inodorous and inoffensive liquid,
without having lost its fertilizing properties. It is obvious that the transport in the
open air of such a liquid would not in any manner be injurious to public health,
and that the question of transport of the sewage to long distances will be solved
in a simple and satisfactory manner, by means of an open canal. Now waste lands
owe their sterility not only to the absence of manure and of water, but also to the
want of cominunications that would supply them with the organic and inorganic

page_text: In order to purify this sewage I have employed per cubic metre 375 grammes of
caustic lime, and the liquid separated from the precipitate has been treated with
75 grammes of sulphate of alumina of commerce and subsequently with 25 grammes
of chloride of zinc.
This mode of purification is distinguished from all similar processes by this
peculiartty that the action of the reagents employed, lime, and sulphate of alumina, is
successive. This succession is a sine qua non condition of success. The lime
employed only precipitates the matters in suspension, and a portion of the matters
dissolved, but it only very imperfectly removes the foetid odour, in fact, it after a
short time increases it. The sulphate of alumina, employed alone, clears the liquid
and destroys the bad odour but the voluminous and gelatinous precipitate which it
causes when used alone, renders the necessary filtration impracticable on a large scale.
It is this filtration, which is the stumbling block to all purifying processes where salts
of alumina are employed as sole purifying reagents. In treating on the contrary the
liquid resulting from the action of the lime with sulphate of alumina a quantity of
loose organic matter is precipitated, which does not offer any obstacle to the filtration.
The separation of the organic matters precipitated by the lime, which cohere easily
in virtue of their relatively great density, is effected by aid of the apparatus hereafter
described. The apparatus consists of a large reservoir a a, b b', Figures 1, 2 and 3,
called the depôt, at the ends of which are affixed respectively an inlet g and an
outlet f. In the culvert i flows the sewage from both sides, and passes by means of
a tube suitably curved into the part whence it flows by the run off pipe ab into
the large reservoir, and in this it deposits the matters precipitated by the lime. The
dimensions of the three parts forming the separation apparatus, are calculated in such
manner that the speed of the sewage holding the precipitated matters in suspension
may be sufficiently slow when the liquid passes into and through the reservoir, so that
without being absolutely stationary it will deposit these matters which are collected by
means of an archimedean screw j rotated upon the bottom of the reservoir by means
of suitable gearing, and carried into a well K whence they are removed by the elbow
tube suitably placed in the container o during which operation the purified waters
run off through a into the let off channel f and thence they pass off through
the bent pipe e to their destination.
B. MODE OF TRANSPORT BY CANAL.
Apart from the novelty of its employment, from the peculiar character of its water
and from the novel object that it is desired to attain, we have nothing to say from a
mechanical point of view of the canal in question. The construction is similar to any
other canal used for internal navigation and its dimensions necessarily depend on the
volume of waters which it has to carry and the purposes for which it is designed.
We have said that the lime precipitates the matters in suspension which the sewage
contains as well as a part of the organic matters that it holds in solution. This
precipitate gathered in the form of liquid sediment expelled by the archimedean screw,
Apart from the novelty of its employment, from the peculiar character of its water
and from the novel object that it is desired to attain, we have nothing to say from a
mechanical point of view of the canal in question. The construction is similar to any
other canal used for internal navigation and its dimensions necessarily depend on the
volume of waters which it has to carry and the purposes for which it is designed.
We have said that the lime precipitates the matters in suspension which the sewage
contains as well as a part of the organic matters that it holds in solution. This
precipitate gathered in the form of liquid sediment expelled by the archimedean screw,

page_text: manure equivalent to a good farm dung. But it is important to remark that
pendently of the serious difficulties which the drainage of this precipitate, suspended
in thrice its weight of water, presents, its drainage in so far as manure, will necessarily
be only in a confined and relatively insufficient extent. The production, besides being
incessant, obstruction would soon take place, and with it the grave inconvenience that
it carries along with it. It is besides desirable that these liquid sediments be dis-
tributed on the soil to be fertilized in order to give it the degree of porosity and
lightness which constitutes the physical character of soils of the first class. All these
considerations have occupied us in effecting the transport of the liquid sediments by
means of a tube of iron or of masonry of 0,18 to 0,20 of interior diameter which
follows the direction of the transport canal throughout its entire length, and which
serves to distribute these sediments wherever necessary.
C. IRRIGATIONS.
We will suppose in the following that the sewage will be distributed over a farm
of two hundred hectares, these forming a small part of the ground that would be
necessary to usefully absorb the sewage of a large centre of population. These two
hundred hectares form in their entirety a rectangular surface of 2000 metres long
and 1,000 metres wide. This fixed, let this rectangle be divided into six equal parts,
by seven canals parallel to each other and to the long side A B of 2,000 metres
each canal being of a section proportioned to the daily supply of sewage. These
seven canals are also connected at B C and A D by two canals at right angles thereto,
of the same section which bound them laterally and cause them to communicate with
the irrigating canals of the fields. The distance between the 2 consecutive and
parallel canals is 161 metres and is settled by the following considerations. A man
bearing a hose fixed at the extremity of a flexible hose 20 metres in length and placed
at a (see plan 4 annexed to the description) will be able to irrigate by the jet from
his hose the portion of the ground comprised in between y and y, that is to say a
width of 40 metres. A second man, also supplied with a hose, 60 metres long and
placed at will be able to irrigate all the ground contained between d and d¹ that is
to say a fresh width of 40 metres so that acting simultaneously the two men will be
able to irrigate an extent of ground 80 metres wide, the respective hoses being
supplied from the same canal E, F and from the same side of it. But from the other
side of this canal the same arrangements being effected, a space of 160 metres wide
will thus be submitted to irrigation by hoses, that is to say a space equal to that which
separates two constitutive canals.
If the hose he now moved according to the progress of the irrigation, in directions
always parallel to those of the canals the irrigation will be able to cover each day
the 200 hectares constituting a farm. When the state of the fields under cultivation
no longer permits of motion paralell to the irrigating canals then the workmen keep
to the fields perpendicular to these canals, and employ exclusively the flexible hose
of 60 metres long. Starting from opposite points of two consecutive canals, they
walk towards each other whilst irrigating on the same side, until they are only
separated by a distance of 40 metres. They then water in front of them as far as their
hose will carry, then returning to the points of departure they water during their
return the other side of the field. They then go to the following field, distant
40 metres from the preceding one and repeat the same operation. It will be seen from
the calculation that in order to distribute the sewage in 24 hours over a farm of
200 hectares, 22 cubic metres to the hectare, it is necessary to make use of a force of
20 horse power and to employ 8 men carrying hose with nozzles 4 square centimetres
in size.
Now the irrigating canals having a depth of 1 metre 50 and a width of 5 metres
close to the ground they are consequently capable of supporting a pontoon, carrying
an engine of above 20 horse power which pontoon being towed by a man will slowly
traverse the canals with a speed suitable to the progress of the operation. Under these

page_text: conditions the persons required, will be an engine driver, a tower, and 8 hosemen.
Compared with the system of irrigation by hoses receiving water from iron conduits,
our system is distinguished by its extreme economy. But this economy is the least of
its advantages. In fact, each farm of 200 hectares thus presenting 7 canals, each
of 2000 metres length, distant from one canal to the following 161 metres, and
connected laterally by two canals of 1,000 metres length the country to be fertilized
will thus be covered with a network of navigable ways which supply it with the
necessary water and manure. Besides all these canals communicating with one
another and ending, directly or indirectly, in the canal for the transport of sewage or
with other large traffic ways of any kind which they may meet with in their course,
the cultivator will be able to use them for the economic transport of his agricultural
produce. The great advantage of this system is that it transforms into green fields,
land which is now sterile owing to the absence of water, of manure, and above all, of
means of access. In certain cases, notably in the case of large extents of valueless
land the employment of hosemen may with advantage be done away with, a great
developement being given, in place thereof, to the irrigating canals. With this
hypothesis, the interval between the consecutive parallel canals will be 80 metres in
place of 160 metres, whilst augmenting the capacity of the hose to a distance of
40 metres, the irrigation could be effected by means of hose fixed immovably at each
side of the pontoon, inclined at an angle of 45 degrees and capable of an automatic
circular movement of up to 90 degrees and back again. In this case the number of
attendants will be reduced per farm to an engine man superintending the hosemen, a
fire man and a towing man.
Having now particularly described and ascertained the nature of my said invention,
and in what manner the same is to be performed, I declare that what I claim is :-
(1.) The mode of purifying sewage and obtaining a clear, limpid, inodorous and
inoffensive liquid therefrom substantially as described.
(2.) The separating apparatus of which I have given the discription and illustrated
in the drawing as well as the revivification of the salts of alumina and zinc employed.
(3.) The employment of a canal open to the air for the transport of sewage, the
water of which canal consisting of purified sewage, whatever be the mode of purification
employed This mode of transport being absolutely new and obtaining a new result
tried for in vain up to the present time.
(4.) The employment of a tube of iron or masonry for the transport of the liquid
manure produced by the above described process.
(5.) The net-work of irrigating canals as above described and also characterised by
the following properties 1st. being supplied with the purified sewage and serving for
irrigation 2nd. permitting the distribution of the sewage by means of the new
improved portable system, pontoon and engine previously described. 3rd. The
construction of a system of navigable channels with communications with each other,
and in connection with the main water ways and also with all parts of the country to
be fertilized.
The whole substantially as described and illustrated in the accompanying drawings
0
D
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool,
& 323, High Holborn, London,
Patent Agents for the Applicant.