Improvements in Purifying the Sewage of Cities and Towns and Foul Waters Discharged from Breweries, Tan Yards, Glue Works, and other description of Manufactory.
Year: 1890

page_text: Date of Application, 3rd Feb., 1890
Complete Specification Left, 3rd Nov., 1890-Accepted, 3rd Feb., 1891
PROVISIONAL SPECIFICATION.
Improvements in Purifying the Sewage of Cities and Towns and
Foul Waters Discharged from Breweries, Tan Yards, Glue Works,
and other description of Manufactory.
I, GEORGE WHIFFEN EWENS of Percy Hall, Malago Vale, Bristol in the
County of Bristol Manufacturing Chemist do hereby declare the nature of this
invention to be as follows:-
This invention has for its object improvements in purifying the sewage of cities
and towns, and foul waters discharged from various manufactories.
All known methods for purifying sewerage have virtually broken down so far as
universal adoption is concerned, the principal cause of failure has been that the
solid matters alone have been precipitated leaving the albumenoids in the effluent
water instead of utilizing the albumenoids to cleanse the whole. By my process
the albumenoids contained in the sewerage are utilized and become the principal
agents in the cleansing.
I find from analysis of the sewage taken from the main sewers of sundry cities
while discharging their normal quantity and in its normal condition that it contains
from one to one and half per cent. of suspended albumenous matter, and that this
matter readily dissolves by adding to the fluid body a little muriatic, sulphuric, or
other acid where it becomes an adhesive slimy mucus which readily adheres to all
the solid matters, and that when in this condition by using an alkaline re-agent such
as hydrate of lime or slaked lime sifted and mixed with water or some form of soda
or potash just sufficient to neutralize the acid all these albumenoids either in suspen-
sion or solution together with the solid matters become a coagulated mass almost
instantly, and very quickly precipitates to the bottom of the tank, leaving the
effluent water clear and bright without either taste or smell. In order to give time
for the acid to act upon and dissolve these albumenoids and to save the heavy
expense of making receiving tanks I add the acid to the sewerage whilst it is still
at a distance from the settling tanks and some time before it can enter these tanks.
I can accomplish the object by placing at the head of the main or intersecting
sewers small tanks composed of either lead, glass or other materials unaffected by
the acid to be used from which the contents may drip or flow at the speed required
into the sewer below, so that by the time the sewage reaches the cleansing tanks
all the albumenous matters will be dissolved. At this stage the sewage should flow
into the cleansing tanks with a fall say of 10 or 12 inches where possible and at this
point should be added the requisite proportion of the alkaline re-agent, hydrate or
milk of lime, or a solution of soda or potash or other alkali which would be mixed
with the sewage by the plunge from the sewer.
The alkaline reagent may be conducted from a mixing apparatus in an adjoining
building by means of a small hose pipe or an open movable shoot. The proportion
of both acid and alkali to be used can be easily ascertained by the effect on the
sewage at the fall, in which a coagulation should be immediately formed and a
consequent precipitation of all solid bodies and matters leaving the effluent water
clear and brilliant to flow on and over the dam at the far end of the cleansing tanks
or reservoirs.
The proportion of both acid and alkali will be entirely governed in each case by
the acid or alkaline character of the sewage and also by the length of time the
sewage takes to flow from the acidulating tanks to the cleansing tanks or reservoirs,
the longer the time the less proportion of acid will be required. Thus, the sewage

page_text: taken from Cheltenham, Bath, Bristol (North and South outfalls) and Exeter
1 in 15000 will be effectual after one hours working of the acid but 1 in 12000 with
half an hours working of the acid.
The number of cleansing tanks must be governed by the requirements of each
particular case they may with advantage be made say three times as long as they
are wide and ranged side by side being divided from one another by strong walls.
The floor of the tanks may be either brick or concrete which should have an incline
towards the overflow dam say of about 1 in 100, and round the outer walls of the
whole of the tanks should be a trench carried down a few inches below the floor of
the tanks, this trench should be filled up with rough stones well rammed down to
support the wall and to carry away the soakage from the surrounding land by a pipe
leading to the outflow. At the upper or feed end of each tank I form an incline
from the high level down into the tank laying down a tram line with branch lines
and diverting points to the sides to facilitate the emptying of the tanks whenever
required, the wagons running on the tram rails could be worked with wire rope from
an engine.
When sewage has been allowed to flow continuously luto any one of the tanks
and the deposit from the sewage appears nearly level with the surface of the water
the sewage must be diverted into another tank and the full one emptied of liquid,
this I accomplish in the following manner. Across the tank near its outlet end and
floating on the liquid within it are thick deal planks. Each plank or float has 3 or 4
copper tubes passed down through it-the lower end of each tube is brought flush
with the under side of the plank or float-the upper end of each tube is bent down-
wards over the side and has coupled to it a length of flexible hose pipe which is
connected with a pipe which passes through the dam and projects into the tank on
a level with the floor. These suction pipes would draw off all the clear effluent
water as the soil subsides and the floats being attached to holdfasts on the dam they
will work down to a certain level to which the soil is ascertained to rise and then
being prevented from descending further would cease working without attention.
A sufficient number of these suction pipes should be provided to discharge the fluid
contents say in about 6 or 8 hours. The semi-solids which will probably be about
one fourth the depth of the tank have now to be dealt with. The lime contained in
this body will still be acting upon the albumenous matter and causing the whole to
contract and become more solid, by this contraction a considerable quantity of
water will be liberated and will percolate to the lower level at the outlet end
of the tank where it is drawn off through a filter-of this I lay down the full
width. The filter may be formed of an iron two inch pipe. Perforated at the top
and sides laid across the end of the tank one brick below the level of the floor and
connected at each end with a pipe running through the dam to the outflow and
having a tap at the end to be opened only when the filter is at work.
Across the whole width of the tank at a short distance from the outlet I place a
strong fine wire gauze about 18 inches high well supported by iron uprights let well
down through the floor, inside this and on the perforated pipe I have a layer of
coarse coal ash cinders and over this fill up with fine sifted cinders, through this
the remaining water would percolate clear and the mud would soon become suffi-
ciently solid to fill into the team waggons, these could be drawn out to the higher
level and the contents thrown up into high banks where it will quickly heat and
become dry by evaporation. It can then be pulverized and packed in bags for sale,
and having the ammonia and phosphates in a perfectly soluble condition would be
of great value to the farmer.
Dated this 1st day of Kolmow 1000

page_text: COMPLETE SPECIFICATION.
Improvements in Purifying the Sewage of Cities and Towns and
Foul Waters Discharged from Breweries, Tan Yards, Glue Works,
and other description of Manufactory.
I, GEORGE WHIFFEN EWENS, of Percy Hall, Malago Vale, Bristol, in the
County of Bristol, Manufacturing Chemist, 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 for its object improvements in the cleansing and purifying the
sewage of cities and towns, and foul waters containing decomposing organic or
other objectionable matters discharged from various manufactories.
Sewage consists very largely of solid matter, decomposed and decomposing
organic and albuminous substances both in suspension and solution and more or less
of all sorts of chemical agents either of an acid or alkaline character from the
discharge waters from local manufactories, any successful method of cleansing the
sewage of any town must be an elastic one capable of being regulated to
the requirements of each case.
So far as universal adoption is concerned all known systems of cleansing sewage
have broken down partly from this want of adaptability and partly from the
expensive agents employed, but principally from beginning to deal with the sewage
at the wrong end by simply precipitating the solid matters and neglecting to call to
their assistance the albuminous substances which so largely impregnate the sewage
and which I utilize as the principal agent for its perfect cleansing.
I find upon analysis of the sewage of various towns while discharging their normal
quantity and condition that the sewage contains from 200 to 350 grams per gallon
of albuminous matter either in solution or suspension and that this matter readily
dissolves and enters wholly into solution by adding to the fluid a due proportion
(just sufficient to acidify it) of either muriatic, sulphuric or other acid when it
becomes an adhesive mucus which readily adheres to all suspended matters and that
when in this condition by using an alkaline re-agent such as hydrate of lime or
slaked lime mixed well with water, or some form of soda or potass just sufficient to
neutralize the acid all this albuminous matter is immediately withdrawn from
solution into suspension and being mixed with the suspended matters the whole
very rapidly precipitates leaving the effluent water brilliant without taste or smell.
In some cases such as where there is a large discharge from breweries containing
a lot of dead ferment or yeast it will be necessary to allow the effluent after going
through the above named process to flow over blocks of sulphate of alumina placed
on a slot on a dividing wall in the cleansing tank.
Now in order to give time for the acid to act on the albumen and to save the
heavy expense of constructing receiving tanks I can accomplish the object by
placing at the head of main sewers tanks of a suitable size lined with lead, glass
or other materials unaffected by the acid from which the contents may flow in due
proportion into the sewers so that by the time the sewage reaches the cleansing
tanks the albumen will be dissolved at this stage the sewage should have as deep a
fall into the tanks as possible so that the agent may be well and violently mixed,
at this point the alkaline re-agent in due proportion should be added with the
plunging sewage. This alkaline solution can be conducted from mixing apparatus
in an adjoining shed by a pipe but an open shoot moveable from one tank to another
will be best as pipes are apt to choke with deposit. The due proportion of lime
being ascertained by its neutralizing the acid the result on the sewage is imme-
diately visible by the coagulation of the albumenoids mixed with all suspended
matters and a very rapid precipitation takes place, the effluent then flows on and
over the dam at the other end of the tank. The proportions of both acid and
alkali must be entirely governed by the character of the sewage and also by the
length of time the sewage takes to flow from the acid tanks to the outfall works,

page_text: 120,000 is sumcient-in others i mno,000 is neened.
CLEANSING TANKS.
The number of tanks must be governed by the requirements of each case, but in
their construction they may with advantage be made 3 times as long as wide,
divided from one another by 26 inch good brick walls well supported every 25 feet
with brick buttresses and the whole faced with good cement. If these tanks are
wholly or partially sunk a trench should be formed round the outer walls to a little
below the floor of the tanks and this trench should be filled up with rough
stones well rammed down to support the wall and carry away to a drain any
land water that would otherwise force the cement from the floors or sides and
prevent a proper drainage of the sludge. The floors of the tanks should have an
incline or slope of say 1 in 200 from the receiving end to the overflow end by this
means the sludge when relieved of the water by the means hereafter named will
gradually drain itself and become solid enough to dig out. At the most convenient
end of each tank an incline may be cut from the land level down to the floor of the
tank to carry a 24 inch tram line with diverging lines through the length of the
tanks so that the sludge when solid may be filled into small trams and drawn up
the incline to the land level. When either tank is so full of sludge that it shews to
the surface the flow should be shut off and diverted to another tank and the
superincumbent water should then be discharged. Instead of valves which draw
from the bottom I do this by having in each tank floating planks of suitable lengths
3 inches thick to prevent canting and with holes perforated vertically through them
at intervals apart, into each hole I screw one end of say 2 inch metallic tube
preferably a right angle bent tube until the lower end of the tube is flush with the
underside of the plank and to the other end of the tube I secure a flexible rubber
pipe these I connect with iron pipes let through the dam on a level with the floors
of the tanks.
When the above syphon pipes are required to be brought into use they can
simply by pushing the plank under the water be caused to start discharging water
from the surface and they will continue working without attention. As the sludge
gradually becomes more solid by the action of these syphon pipes the agents used
in the cleansing process will then exert a contracting force on the albuminous matters
and the remaining fluid in the sludge will be liberated and being of a lighter gravity
than the solid matters will rise to the surface and flow on towards the lower level
for discharge, when these syphon pipes have ceased to act there will still be
a percolation from the sludge, this I would discharge by laying down a few inches
below the level of the tank floors a 2 inch iron pipe perforated top and sides each
end connected with an outflow pipe carried through the dam having a screw tap at
each end to be opened when required to work. Over this perforated pipe I would
have a layer of coarse cinders and then fill up the space with finer cinders, these
could be kept in their place by running along a length of wire gauze supported by
iron stauncheons sunk in the floor.
The sludge I treat in the following manner.
The usual method of treating sludge by pumping it out into earth pits and
allowing it to drain on land is a very crude and objectionable method, the land is
soon overloaded and the atmosphere polluted with dangerous gases keeping back in
or near towns the nuisance the works are intended to prevent and in many towns
the soakage from these sludge pits into a brook or stream renders the supposed
cleansing a mere sham. Now I find that when the sludge by its own natural
drainage in the tanks has become solid and it is then dug out and tipped from the
trams into certain receptacles and after being beaten down into a firm mass and then
covered over with a layer of well puddled clay of an inch or two in thickness
smoothed over with a spade to exclude the atmosphere. The organic matters in the
sludge will at once commence to ferment and heat and the whole mass in a very

page_text: short time reduce itself into a dry powder retaining all its ammoniacal properties as
a valuable manure.
For this purpose I would have constructed above the level of the land a certain
number of brick silos as may be required by building a series of walls 8 or 10 feet
high 100 to 200 feet long with spaces between them of 20 or 25 feet, with a tram
road running the length of each. These spaces to be filled to the top of the walls
with the solid sludge and as filled up covered over with a clay crust to heat.
When reduced to a powder it can be put into bags and sold for the purposes of
agriculture for which it will be of great value as the phosphate and ammonia will
be perfectly soluble and the manure can be run on the land from a drill.
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. Purifying sewage by first acidulating it in the sewers thereby dissolving the
albuminous matters and subsequently neutralizing the acid in the sewage by an
alkaline agent thereby causing a rapid coagulation of the albumen with all suspended
matters, resulting in speedy precipitation.
2. Purifying sewage by first acidulating it then neutralizing the acid in the
sewage and allowing the precipitated matters to settle from the sewage as it passes
slowly through a settling tank substantially as described.
3. The settling tanks constructed with draw off syphon discharge pipes and
discharge drain at the bottom to draw off and separate water from the sludge
substantially as described.
4. The treatment of the sludge in silos substantially as described to cause natural
fermentation by its own heating properties.
Dated this 6th day of October 1800.
GEORGE WHIFFEN EWENS.