Improvements in or relating to the Purification of Sewage and Apparatus therefor.
Year: 1897

page_text: Date of Application, 31st May, 1887
Complete Specification Left, 28th Feb., 1898-Accepted, 28th May, 1898
PROVISIONAL SPECIFICATION.
Improvements in or relating to the Purification of Sewage and
Apparatus therefor.
I, WILLIAM DUNDAS SCOTT-MONCRIEFF, of 14, Victoria Street, Westminster,
Engineer,, do hereby declare the nature of this invention to be as follows:-
This invention has relation to certain. improvementa in or relating to the
purification of sewage and apparatus therefor and has for its special object the
provision of favourable conditions for the working of the organisms, of liquifaction
and nitrification in addition to those set forth in my Patent Specifications
Nos. 14181-1891, 17006-1892.
The description of these improved and novel conditions may be divided under two
heads 1st the novel process itself 2nd the means adopted to carry it out. Thesc
means, for the most part are not novel in themselves but consist of novel con-
binations of known appliances.
As regards the novel process, my present invention consists in realising a
certain sequence or cycle of operations which are partly bacteriological and partly
chemical but wholly embraced within the life history of the various organisms
employed in the process and not dependent upon the use of any artificial chemical
substances.
The steps or stages in the process may be repeated either in their whole sequence
or in parts of it, but the essential character of the completed cyole is that
the organic matter contained in the sewage should be finally delivered to the
organisms of nitrification freed as far as possible from the presence of the
organisms employed in the earlier stages of the process and also from their
enzymes or products.
In order to attain this result I alter the conditions which are favourable for the
growth of the organisms which require oxygen as soon as they have performed
the maximum of change which can be obtained from them and I then pass the
Liquified sewage containing them through a tank or chamber provided with highly
anoerobic conditions the most unfavourable possible to the continuance of the
oerobic varieties. As a result of this part of the process an effluent is obtained
which will be highly charged with anoerobic organisms and with a number of
unstable chemical substances having a great affinity for oxygen. I then provide
conditions highly unfavourable to growth of the anocrobic organisms and I make
provision for these conditions being repeated over and over again until the least
possible number of anoerobic organisms survive and until the enzymes or products
of the earlier stages of the process have been broken up as far as possible by
contact with air. In this way, by employing conditions which are alternately
favourable to some organisms and unfavourable to others I am able to do what
bacteriologically speaking would be very difficult by using either one set of
conditions only or either of them continuously.
Dealing with the methods which I employ for obtaining these results, I do not
rely upon any particular means for doing so as the novelty of the process just

page_text: described forms the principal subject matter of my present patent, but preferably
I use the apparatus as set forth in my Patent No. 14181-1891, or any convenient
modification of it and I do this in order to obtain as much work as possible from
the mixed organisms contained in the sewage. 2ndly I use a closed chamber or
tank filled with inverted, open mouthed vessels of any convenient size or material
in which the gasses arising from the life processes of the organisms are occluded
and which provide highly anoerobic conditions. 3rdly I use a series of open
tanks filled with various sizes of filtering materials whose surfaces provide for a
large exposure to the action of the air and I pump, by any convenient means the
sewage effluent from one of these open tanks into another open tank through
pipes or nozzles 80 arranged as to sprinkle the effluent upon their upper surfaces
and so that it is always falling through, them and is pumped away from the bottom
of one tank over the surface of another tank sufficiently often to allow of the
enzymes or products being oxygenised and so that the last tank or filter may be
ablo to retain uninjured a special cultivation of specifically nitrafying and nitri-
fying organisms which complete the work of purification which if necessary, may
be aided by the resting of any or all of the tanks.
Where there is a sufficient fall I utilise the force of gravity for raising and
distributing the effluente in place of mechanical means. In the event of any
offensive smolls arising in the process, I enclose the tops of the various open tanks
underneath glass roofs and I make provision for burning any of the combustible
gasses arising from the process.
Dated thin 98th day of May 1897.
Improvements in or relating to the Purification of Sewage and
Apparatus therefor.
I, WILLIAM DONDAS SCOTT-MONCRIEFF, of 14, Victoria Street, Westminster,
Engineer, 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:-
This invention has relation to the purification of sewage and apparatus therefor
and has for its special object the provision of favourable conditions for the
working of the organisms of liquefaction and nitrification in addition to those
set forth in my Patent Specifications No. 14181 of 1891 and No. 17006. of 1892.
The description of those improved and novel conditions may be divided under
two heads, lat. The novel process itself; 2nd. The means adopted to carry
it out. These means for the most part are not novel in themselves but consist of
novel combinations of known appliances.
As regards the novel process my invention consists in realising a certain
sequence of operations for the purification of sewage by means which are partly
bacteriological and partly chemical, but wholly embraced within the life history of
the various organisms employed in the process and not necessarily dependent upon
the uso of any artificial chemical substances.
The steps or stages in the process may be repeated oither in their whole sequence
or in parts of it, but the essential characteristic of the completed sequence is that
the organic matter contained in the sewage should be delivered to the organisms of
nitrification freed as far as possible from the presence of the organisms employed
in the carlier stages and also from their enzymes or substances which may be

page_text: inimical to the working of the organisms in the further stages. In order to
attain this result I alter the conditions which are favourable for the growth of
the organisms which require oxygen as soon as they havo performed the maximum
of bencficiul change which can be obtained from them and I submit the liquefied
Bewage containing them to highly anaerobic conditions the most unfavourable
possible to the continuance of the aerobic varieties, and a convenient way to effect
this is to pass the sewage through a tank or chamber provided with these special
anaerobic conditions.
As a result of this part of the process an effluent is obtained which will be
highly charged with anaerobic organisms and with a number of unstable chemical
substances having a great affinity for oxygen. I then provide conditiona highly
unfavourable to the growth of the anaerobic organisms and highly favourable to the
aerobic organisms and I make provision for these conditions being n peated over
and over again until the least possible number of anaerobic organisms survive, and
until the enzymes of the carlier stages of the process have been broken up as far
as possible by contact with air, and the purification is completed in a bacterio-
logical sense.
In this way, by employing conditions which are alternately favourable and
unfavourable to different kinds of organisms respectively I am able to do what,
bacteriologically speaking, would be very difficult by using either one set of
conditions only or either of them continuously. For instance by employing
anaerobic conditions only to begin with and then delivering the product to the
organisms of nitrification the latter will be destroyed or at any rate fail to not woll
continuously. By using an aerobic process to begin with and delivering the product
to the organisms of nitrification the fluid will be highly charged with the ordinary
organisms of liquefaction and the organisms of nitrifaction will fail to act well con-
tinuously. Again by using mixed nerobic and anaerobic conditions throughout a
mixed survival of organisms employed to complete the process would equally result
unfavourably to the organisms of nitrification.
By the improved process of providing alternately favourable and unfavourable
conditions to the different kinds of organisms respectively the best result may bo
attained.
Dealing with the methods for obtaining these results I do not limit myself
to any particular means of doing so, as the novelty of the process just described
forms the principal feature of my present invention, but preferably I uso 1st. the
apparatus as set forth in my Patent No. 14181 of 1891 or any convenient
modification of it, and I do this in order to obtain as much work as possible from
the mixed organisms originally contained in the sewage, 2ndly. I use when highly
anaerobic conditions are required, a closed chamber or tank filled with inverted
open mouthed vessels of any convenient size or material, in which gases arising
from the life processes of the organisms are occluded and which provide highly
anaerobic conditions; inasmuch as a number of fixed intermediate liquid sur-
faces or septic cells are formed within the body of the liquid, these surfaces being
all in contact with the occluded gases in the inverted vessels among which the
sewago partly broken up by the first process rises; 3rdly. I then pass the liquid
from the closed chamber or tank above described to a series of open tanks filled
with filtering materials whose surfaces provide for a large exposure to the action
of the air and I pump by any convenient incans the sewage effluent from one of the
open tanks to another open tank through nozzles or pipes so arranged as to sprinkle
the effluent upon their upper surfaces and so that the effluent falls through them
and is pumped away from the bottom of one tank over the surface of another
lank sufficiently often to allow of the enzymes being oxidized so that the last tank
may retain uninjured a special cultivation of specifically nitrifying or oxidizing
organisms which complete the work of purification.
Where there is a sufficient fall I utilize the force of gravity for. distributing
he effluents in place of mechanical means.
In the event of any offensive smells arising in the process I enclose the tops

page_text: of the various open tanks underneath glass roofs and I make provision for burning
any of the combustible gases arising from the process, particularly in the second
stage in which the gases in the inverted vessels are liable to bubble out when
the vessels become surcharged.
Figure 1 of the accompanying drawings is a plan of an apparatus suitable for
carrying out my invention; Figure 2 is a section on the line 2-2-2 of Figure 1;
Figure 3 is a section on the line 3-3.
In these figures, A is the intake for the crude sewage. B is a chamber into
which the fluid is delivered. At the bottom of the chamber is a sump C to receive
any grit &c. that may be deposited therein and this grit &c. may be removed by
any suitable means as for example by a chain pump. D is a tank adjoining the
chamber B; the bottom of this tank has at one part an opening covered with a
perforated or foraminous diaphragm E, below which is a channel F communicating
with the lower part of the chamber B by the opening G. The tank D is filled.
preferably up to a little above the overflow outlets H with materials such as flints,
stones or the like to form a surface to which the bacteria may adhere. The sewagn
which enters the chamber 13 passes through the opening G into the channel F
and thence through the diaphragm E into the tank D. It rises through the
material in the tank and flows out through the overflow outlets H into the
channels J. The crude sewage contains a varying amount of oxygen which is
available for the action of aerobic organisms that is to say the organisms which
require oxygen and which are contained in the sewage or are deposited on the
surface of the materials in the tank 1); the first stage in the process of purification,
that is to say, the breaking up of the organic matters takes place in the tank D
due chiefly to the action of these aerobic organisms which first of all use up the
available oxygen in the sewage and then attack the oxygen contained in the organic
matter itself the result being that a considerable amount of liquefaction takes
place.
From the tank D the more or less broken up sewage flows by the outlets H into
the channels or pipes JJ by which it is delivered to the lower part of a closed
chamber or vessel K. In this chamber above the delivery ends of the pipes J J is
a perforated plate or false bottom L. Above this bottom the chamber is filled
with inverted open mouthdl vessels M M in which gases arising from the life
progress of the organisms are occluded and which provide highly anaerobio
conditions as herein before explained, the effect of which is to further break up
the organic matters in the sewage as this finds its way up between the vessels.
N is the outlet for the liquid from the closed chamber K. This outlet discharges
on to a trough P mounted so as to automatically tip when filled to a given depth.
When it tips it discharges its contents into a series of trays R with perforated
bottom and these in turn distribute or sprinkle the liquid upon the top of the
first of several open tanks Q Q' (of which I show only 2 but more will generally
be employed). The tanks are filled with filtering material such as coke whose
surface provides for a large exposure to the action of the air. From the bottom
of the first tank the sewage effluent is pumped or otherwise conveyed to a trough P¹
like the trough P and which discharges intermittently into the trays R' and these
in turn distribute or sprinkle the liquid upon the top of the second tank, and so
on to the third, fourth, &c. tanks successively, when more than two are employed.
From the bottom of the last tank the effluent is conducted to any suitable place
of discharge. Various modifications of the complete sequence may be introduced
so long as in the last stage of the process in which the sewage is submitted to
organisms at work under highly aerobic conditions there is (as in the tanks QQ'
a continuance of the process by a series of colonies of organisms naturally or
artificially selected to deal with the particular stage of the food supply as it reaches
them.
Where conditions are present for the subjection of the sewage to sufficient
anaerobic change to obtain the maximum advantages from this part of the process
any such method as the use of inverted vessels as described can be dispensed

page_text: with, these inverted vessels having been clevised with the object of intensifying
the anaerobic changes when it is desirable to do so and also with the view of
curtailing the amount of apparatus necessary by reason of the increased activity
to be obtained by adopting them. The separate anaerobic tank may for example
be dispensed with if the tank D be of such depth that all the oxygen is consunied
in the lower part of the tank so that the upper part of the tank and the flints or
like material at such upper part are in anaerobic conditions.
Figure 4 represents in plan and Figure 5 in side elevation a special construc-
tion of apparatus which I have tlesigned in lieu of the tanks Q Q for submitting
the sewage in the nitrifying stage of the purification process to the successive
action of a series of colonies of organisms under highly aerobic conditions. I
make no specific claim to the particular construction of apparatus shown in
Figures 4 and 5 as it is embodied in a subsequent application for Patent No. 18555
of 1897. In these figures, J represents the pipe which conducts the sewage from the
anaerobic chamber K Figures 1, 2 and 3 or other place where it has been subject to
highly anaerobic conditions. The pipe J delivers the liquid to a channel K having
a series of nozzles KK; these deliver the liquid to a series of troughs MM (seen
more clearly in the detached view Figure 5 which is on a larger scale) so mounted
on trunnions NN as will be well understood that when empty or only partly
full they automatically preserve the horizontal position shown in Figure 6 but
when filled up to a given level they are overbalanced, tip on their centres N, pour
out their contents and return to the horizontal position. Below the troughs M M
is a series of superimposed filters PP with a clear air space between them. These
filters, the uppermost of which receives the sewage which is intermittently dis-
charged by the troughs are composed of trays with perforated bottoms and filled
with suitable filtering material such as broken coke. The sewage drips from the
uppermost tray P to the next tray below and so on and during its passage through
the filtering material in the trays and while passing through the clear air spaces
between the trays highly aerobic conditions are established which are greatly
favourable to the work of the aerobic organisms and in this way as is the case
with the tanks QQ of Figures 1 and 2 the sewage by a succession of stages
becomes purifial. From the lowest tray the purified sewage falls into the
channel which conducts it to any suitable place of discharge.
My invention does not preclude the addition if thought desirable of foreign
substances at any stage of the process; my claims to novelty are independent of
any such addition.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed, I declare that what I
claim is:-
1. In the purification of sewage bacteriologically, first submitting the crurle
sewage to the action of mixed aerobic and anaerobic organisms, secondly sub-
mitting the result of the first process to organisms, that work under highly
anaerobic conditions, and thirdly submitting the resulting product to organisms
that work under highly aerobic conditions, these last conditions being repeated or
continued by a series of colonies of organisms to the action of which the sewage
is successively subjected, substantially as herein boforo described.
2. In the purification of sewage bacteriologically, submitting the sewage after
the organic matters therein have been broken up in previous stages of treatment
to treatment in a series of tanks or filters (whether superimposed or not) succes
sively, the sewage coming in contact with the atmosphere in its passage from one
tank or filter to the next throughout the series so that it absorbs oxygen from the
atmosphere whereby highly aerobic conditions are established, substantially as
herein before described.
3. In apparatus for the purification of sewage bacteriologically,, tho com-
bination of apparatus in which the sewage is acted upon first under mixed aerobic
and anaerobic conditions and then under anaerobic conditions and of a series of tanks

page_text: or filters (whether superimposed or not) in which the sewage is successively acted
upon by organisms under highly aerobic conditions, substantially as set forth.
4. In apparatus for the purification of sewage bacteriologically, the combina-
fion of (1) a tauk or vessel for the action upon the sewage of mixed organismis, (2) a
closed chamber from which the sewage passes from the said tank or vessel, the
said closed chamber containing inverted open mouthed vessels, and (3) a series of
tanke or filters (whether superimposed or not) to the first of which the sewage passes
from the said closed chamber, and from one to another of which the sewage
passes in succession in contact with the atmosphere, substantially as and for the
purpose set forth.
5. For use in the treatment of sewage bacteriologically a sories of inverted
open-mouthed vessels in a chamber or tank between which vessels the sewage
passes, the said vessels forming intermediate liquid surfaces or septic cells within
the body of the liquid so that the sewage as it rises is submitted to the action of
the gases occluded in the vessels or cells, and of the organisms living on or near the
liquid surfaces, substantially as and for the purpose set forth.
1000
Dated this on way ay
J. O. MEWBURN & ELLIS,
55 and 56, Chancery Lane, London, Chartered Patent Agents.