An Improved Process for Purifying Sewage and Waste Water of a Putrescible Character.
Year: 1894

page_text: Date of Application, 11th May, 1894
Complete Specification Left, 9th Feb., 1895-Accepted, 11th May, 1895
PROVISIONAL SPECIFICATION.
An Improved Process for Purifying Sewage and Waste Water of a
Putrescible Character.
I, OSCAR SCHMIDT of 25 Danzigerstrasse, Berlin in the Empire of Germany,
Merchant, do hereby declare the nature of this invention to be as follows:-
The action of the soil, as well as that of the bed of the stream in the so called
infiltration process, or the self-purification of streams, is based essentially on
apparent absorption both of the unchanged substances, as well as of those which are
modified by the action of micro-organisins and are consequently putrescible, which
substances are contained in the sewage or waste water conveyed on to filtering
beds, or allowed to run into the streams. This apparent absorption, which the
decomposition of the complex organic substances also greatly accelerates, is only
to a small extent brought about by the purely mineral constituents of the soil; the
greater part of this action arising from the so called humus substances. The soil
contains however only a small percentage of these latter, so that it is probable that,
if a soil were made free from the substances which only act mechanically but
consisting on the other hand of humus substances, quite a small fraction of the
same would suffice if care were taken to have a thorough contact of the impurities
with the same, and to have an easy filtration. The soil obtained in this manner
possesses for the above object the advantage of mobility.
The use as at present of ordinary earth or soil has the drawhack that it is
necessary either to thoroughly saturate the upper layer of the same, which always
comes in contact with the substances most charged with impurities, so that all
filtration ceases, or that, in order to avoid this, a very great extent of ground must
be made use of, the obtaining of which naturally comes very dear.
The mode or process of filtration hitherto employed has also the further drawback
that it does not allow of the disinfection of the filtered water or the soil; the
rendering harmless of pathogenetic germs more particularly can only be done under
special circumstances.
An artificial soil however, which contains the necessary mineral substances
(carbonates, silicates and the like) and a 20 to 30 fold quantity of humus substances,
and which can be most finely disintegrated or shaken up, and be always brought
into contact with the sewage water in a fresh, absorbent condition, must be able to
exert such an effect that it is possible to employ the same in place of the immovable
ground soil.
The action of the humus is further increased if salts be added thereto which are
able to precipitate both the saturated humus substances as well as also certain
organic substances from their solutions without chemical alteration, so that they,
like albuminous substances and the like, thoroughly unite with the humus
substances.
Such precipitating substances also exist in a state of solution in the liquid in the
soil, these being more particularly the salts of iron, aluminium and, to a lesser
extent, of magnesium. They are found in the soil liquid in minimum quantities
which may, however, be increased at will.
The process which forms the object of this invention is based on the consideration
of the circumstances hereinbefore mentioned, and, as demonstrated by experiments
conducted on a large scale, is capable of taking the place of the roundabout and

page_text: costly filtration beds, and the nitrogenous contents of the sewage or waste water is
recovered as a high percentage manure which is easily sold, as, if it cannot be
disposed of to agriculturists, it may be employed as a good fuel.
By this process however there is not only obtained a theoretical utilisation of the
manurial value of the sewage or waste water, but it affords the security, in case of
epidemics, of being able at slight cost to disinfect the sludge and the purified water,
in contrast to the present filtration methods.
If finely subdivided humus substances be added to waste water or sewage of the
above named kind, clarification cannot be brought about either by filtration or by
allowing it to settle as at ordinary temperatures the fine particles of humus
themselves are not retained by filter paper, and coarsely subdivided brown coal or
the like is quite without action.
Iron and argillaceous salts alone exert no great purifying effect, as the absorbent
action of the humus substances are wanting and they only yield a precipitate with
certain constituents of the sewage; on the other hand, as Virchow has already
shown, the precipitating capability of the precipitants is weak, and in fact
frequently by a sudden swelling up of the precipitate the action is entirely nullified
and finally passes into stinking decomposition.
Again the decomposition of the sewage water recommended by A. Müller led to
no satisfactory result because it did not provide for constantly removing the fumes
containing bacteria (products of decomposition) given off during the decomposition.
If all three processes combined are allowed to act on the sewage or waste water,
there is obtained
1. A complete clarification;
2. A rapid, permanent, no longer decomposing precipitate;
3. A thorough decomposition without formation of evil smelling products; and
4. A far more complete chemical purification.
Finely subdivided pasty humus substances (such as lignite, turf, peat earth or the
like) in a state of suspension are continuously added to the sewage or waste water
and thoroughly mixed therewith by means of a mixing trough, a sufficient quantity
but not an excess of the soluble salts of iron aluminium and magnesium to cause a
rapid precipitation of the humus substances are then dropped in also continuously.
The water thus treated, clears rapidly and easily. The minud may then be
separated from the clear liquid without difficulty in the usual manner by means of
settling tanks, presses or the like, but preferably by means of the so-called Rothe-
Röckner apparatus.
This latter apparatus has the great advantage over the others that the sewage
which is only slightly decomposing which comes to the clarifying, remains some
hours in contact with the always freshly inflowing humus substances, or with sludge
rich in humus, in which time the decomposing process is completed, the products of
decomposition, etcetera, formed being absorbed, the gases which check the
decomposition being also simultaneously removed.
The process is arranged in such a way that the enriched sludge, some hours old,
is constantly removed, and the clarified water constantly flows away.
The latter then contains about 90% of substances containing permanganate,
and 80-90 per cent. less of nitrogen than the decanted unclarified sewage.
It is
clear, colourless, scentless, neutral and free from organic substances which can be
precipitated with lime, it also contains only traces of salts of organic or carbonic
acids as well as of ammoniacal salts, and is discharged from the clarifying apparatus
in so pure a condition that any disinfection, if such be necessary, may be easily
carried out with small quantities of chemical substances, such as acids or the like.
Dated this 10th day of May 1894.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.

page_text: An Improved Process for Purifying Sewage and Waste Water of a
Putrescible Character.
I. OSCAR SCHMIDT of 25 Danzigerstrasse, Berlin in the Empire of Germany,
Merchant, 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 action of the soil, as well as that of the bed of the stream in the so called
infiltration process, or the self-purification of streams, is based essentially on
apparent absorption both of the unchanged substances, as well as of those which
are modified by the action of micro-organisms and are consequently putrescible,
which substances are contained in the sewage or waste water conveyed on to
filtering beds, or allowed to run into the streams. This apparent absorption, which
the decomposition of the complex organic substances also greatly accelerates, is
only to a small extent brought about by the purely mineral constituents of the soil;
the greater part of this action arising from the so called humus substances. The
soil contains however only a small percentage of these latter, so that it is probable
that, if a soil consisted of humus substances and was freed from those substances
which only act mechanically, only a small quantity of soil would be necessary if
care were taken to ensure a thorough contact of the impurities with the same, and
to have an easy filtration. The soil obtained in this manner possesses for the above
object the advantage of mobility.
The use as at present of ordinary earth or soil has the drawback that it is
necessary either to thoroughly saturate the upper layer of the same, which always
comes in contact with the substances most charged with impurities, so that all
filtration ceases, or that, in order to avoid this, a very great extent of ground must
be made use of, the obtaining of which is naturally very expensive.
The mode or process of filtration hitherto employed has also the further drawback
that it does not allow of the disinfection of the filtered water or the soil; the
rendering harmless of pathogenetic germs more particularly can only be done
under special circumstances.
An artificial soil however, which contains the necessary mineral substances
(carbonates, silicates, and the like) and a 20 to 30 fold quantity of humus
substances, and which can be most finely disintegrated or shaken up, and be always
brought into contact with the sewage water in a fresh, absorbent condition, must be
able to exert such an effect that it is possible to employ the same in place of the
immovable ground soil.
The action of the humus is further increased if salts be added thereto which are
able to precipitate both the saturated humus substances as well as also certain organic
substances from their solutions without chemical alteration, so that they, like
albuminous substances and the like, thoroughly unite with the humus substances.
Such precipitating substances also exist in a state of solution in the liquid in
the soil, these being more particularly the salts of iron, aluminium and, to a lesser
extent, of magnesium. They are found in the soil liquid in minimum quantities
which may, however, be increased at will.
The process which forms the object of this invention is based on the consideration
of the circumstances herein before mentioned, and, as demonstrated by experiments
conducted on a large scale, is capable of taking the place of the roundabout and
costly filtration beds, and the nitrogenous contents of the sewage or waste water
is recovered as a high percentage manure which is easily sold, as, if it cannot be
disposed of to agriculturists, it may be employed as a good fuel.
'

page_text: By this process however there is not only obtained a theoretical utilisation of the
manurial value of the sewage or waste water, but it affords the security, in case of
epidemics, of being able at slight cost to disinfect the sludge and the purified water,
in contrast to the present filtration methods.
If finely subdivided humus substances be added to waste water or sewage of the
above named kind, clarification cannot be brought about either by filtration or by
allowing it to settle, as at ordinary temperatures the fine particles of humus
themselves are not retained by filter paper, and coarsely subdivided brown coal or
the like is quite without action.
Iron and argillaceous salts alone exert no great purifying effect, as the
absorbent action of the humus substances is wanting and they only yield a
precipitate with certain constituents of the sewage; on the other hand, as Virchow
has already shown, the precipitating capability of the precipitants is weak, and in
fact frequently by a sudden swelling up of the precipitate the action is entirely
nullified and finally passes into stinking decomposition.
Again the decomposition of the sewage water recommended by A. Müller led
to no satisfactory result because it did not provide for constantly removing the
fumes containing bacteria (products of decomposition) given off during the
decomposition.
If all three processes combined are allowed to act on the sewage or waste water,
there are obtained
1. A complete clarification;
2. A rapid, permanent, no longer decomposing precipitate;
3. A thorough decomposition without formation of evil smelling products; and
4. A far more complete chemical purification.
Finely subdivided pasty humus substances (such as lignite, turf, peat earth or
the like) in a state of suspension are continuously added to the sewage or waste
water and thoroughly mixed therewith by means of a mixing trough, a sufficient
quantity but not an excess of the soluble salts of irou, aluminium and magnesium
to cause a rapid precipitation of the humus substances is then dropped in also
continuously. The proportions of these substances vary of course according to
the composition of the sewage to be purified, which as is well known varies very
greatly there are however employed per cubic metre of water, that is to say
per 1000 kilos. 25 kilos. up to 10 kilos. of humus substance, such as brown coal,
turf, peat etc., that is to say 25 to 10 per 1000. The quantities of the iron or
other salts employed amount to 06 to 1 kilo. per cubic metre of water, i.e. '06 to
1 per 1000. For town sewage, more particularly, it is necessary to use per cubic
metre about 15 per 1000 of peat, brown coal or the like, and 12 per 1000 iron
salts.
;
The water thus treated, clears rapidly and easily. The mud may then be
separated from the clear liquid without difficulty in the usual manner by means of
settling tanks, presses or the like.
The process is arranged in such a way that the enriched sludge, some hours
old, is constantly removed, and the clarified water constantly flows away.
per
The latter then contains about 90 per cent. of substances containing permanganate,
and 80-90 cent. less of nitrogen than the decanted unclarified sewage. It is
clear, colourless, scentless, neutral and free from organic substances which can be
precipitated with lime, it also contains only traces of salts of organic or carbonic
acids as well as of ammoniacal salts, and is discharged from the clarifying apparatus
in so pure a condition that any disinfection, if such be necessary, may be easily
carried out with small quantities of chemical substances, such as acids or the like.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
An improved process for purifying sewage or waste water of a putrescible
character, consisting in separating the putrescible soluble constituents or those held

page_text: in suspension by producing a precipitation by means of the addition of fiuely
subdivided pasty or spongy humus substances, and by adding thereto soluble salts
of iron, aluminium and magnesium, substantially as hereinbefore described.
Dated this 8th day of February 1895.
WM. P. THOMPSON & Co.,
Of Liverpool, Manchester, Birmingham, and London, Patent Agents.