Improvements in Purifying Sewage and other Foul Liquids and in Making Oil, Alkali, and Cement from Sewage Precipitate, and in Apparatus for that Purpose.
Year: 1886

page_text: Date of Application, 23rd Nov., 1886.
Complete Left, 17th Aug., 1887.
Complete Accepted, 20th Sept., 1887
Improvements in Purifying Sewage and other Foul Liquids and in
Making Oil, Alkali, and Cement from Sewage Precipitate, and
in Apparatus for that Purpose.
I WILLIAM BURNS of 32 Elmwood Terrace Leith in the County of Mid-Lothian
Consulting Engineer and Chemist, do hereby declare the nature of my said invention
for IMPROVEMENTS IN PURIFYING SEWAGE AND OTHER FOUL LIQUIDS, AND IN MAKING
OIL, ALKALI, AND CEMENT FROM SEWAGE PRECIPITATE AND IN APPARATUS FOR THAT
PURPOSE, to be as follows:-
I provide a number of suitable chambers or tanks through which the sewage is
made to pass, Into No. 1 of these chambers I inject hydrochloric acid gas; hot from
the decomposition of chloride of sodium, which the sewage instantly absorbs and
becomes acidulated and disinfected, and then flows into No. 2 chamber, into which I
inject sulphurous acid gas which is instantly absorbed by the sewage and decomposes
the sulphuretted hydrogen contained therein. The sewage then passes into No. 3
chamber and delivers the unabsorbed gases into flues connected with a furnace. The
sewage then flows into No. 4 Chamber into which I inject Chlorine gas, which is
dissolved by the sewage and coagulates the gelatine and mucus substances. I then
cause the acidulated sewage to flow through an agitating or dash wheel containing
charcoal and peroxide of iron, in constant motion, which oxydises the sewage, I then
cause the sewage to pass through a second dash wheel containing chalk and clay
which absorbs the oily substances and part of the salts of ammonia, The sewage is
then passed through a third dash wheel supplied with coal dust and caustic lime in
sufficient quantity to neutralize the acidity of the sewage, I then cause the sewage to
flow over a pair of rollers which crushes the small lumps into finer particles. The
sewage mixed with the foregoing ingredients flows into large precipitating tanks
where the whole of the solid matters are rapidly precipitated, and the effluent water is
made to flow on to filters composed of charcoal iron turnings and sand, The filter is
made with air channels underneath where a current of air is made to flow constantly
under the perforated floor, which oxydizes the charcoal and iron turnings, and the
oxydized charcoal and iron oxydises the sewage water, and renders it sufficiently pure

page_text: for domestic and manufacturing purposes, I then take the precipitate from the tanks,
and pump or lift it into deep settling tanks and continue to draw off the supernatant
water until the sludge is sufficiently stiff to be moulded into bricks or lumps for drying,
I then distill the dry sludge in close blast retorts under high pressure and low
temperature; until all the ammonia and oil is distilled off, I then force the uncon-
densed gases through a mixture of charcoal and peroxide of iron which absorbs the
sulphur, I then pass the gases through a vessel containing depurating charcoal which
causes a combination of part of the mixed gases and forms bicarbonate of ammonia,
The
gases are then made to pass through a vessel containing chloride of sodium, and
then through a saturated solution of chloride of sodium, which absorbs the bicarbonate
of ammonia and produces bicarbonate of soda, and chloride of ammonium in solution.
The remainder of the gases consisting chiefly of hydrocarbons and nitrogen are
conveyed to the boiler furnace and utilized in evaporating the water, After all the
gases have been discharged from the sludge lumps in the retort under high pressure,
I reduce the pressure in the retort and increase the temperature, and then calcine the
residue under high temperature, which converts the sludge lumps into powerful
hydraulic cement. By the above continuous process the sewage is thoroughly purified,
and the sludge is converted into valuable commercial substances.
The novelty of this invention for purifying sewage and utilizing the precipitate,
does not consist in adding and mixing the aforementioned substances, which have all
been used for mixing with sewage in some form or other before; but the novelty
consists;
First In the order or method of adding and mixing the aforenamed
substances in succession the one after the other in separate chambers as herein
described.
Second-In the novel method of utilizing the sewage precipitate or sludge, by
manufacturing oil, alkali, and cement from the said sludge by a novel combination of
apparatus.
Dated the 22nd day of November 1886.

page_text: COMPLETE SPECIFICATION.
Improvements in Purifying Sewage and other Foul Liquids and in
Making Oil, Alkali, and Cement from Sewage Precipitate, and
in Apparatus for that Purpose.
I WILLIAM BURNS of 32 Elmwood Terrace Leith in the County of Mid-Lothian,
Consulting Engineer and 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 :-
I provide a number of suitable chambers or tanks through which the sewage is
made to pass. Into No. 1 of these chambers I inject hydrochloric acid hot from the
decomposition of salt, which the sewage instantly absorbs and becomes acidulated
and disinfected, and then flows into No. 2 chamber into which I inject sulphurous acid
gas, which is instantly absorbed by the sewage and decomposes the sulphuretted
hydrogen contained therein. The sewage then passes into No. 3 chamber and
delivers the unabsorbed gases into flues connected with a furnace. The sewage then
passes into No. 4 chamber; into which I inject chlorine gas, which is dissolved by
the sewage and coagulates the gelatin and mucus substances. I then cause the
acidulated sewage to How through an agitating dash wheel containing charcoal and
peroxide of iron in constant motion, which oxydises the sewage water. I then cause
the sewage to pass through a second dash wheel containing chalk and clay which
absorbs the oily substances and part of the salts of ammonia, The sewage is then
passed through a third dash wheel supplied with coal dust and caustic lime in
sufficient quantity to neutralize the acidity of the sewage. I then cause the sewage
to flow over a pair of rollers which crushes the small lumps into finer particles.
The sewage mixed with the foregoing ingredients flows into large precipitating
tanks where the whole of the solid matters are rapidly precipitated, and the effluent
water is made to flow on to filters composed of iron turnings charcoal and sand.
The filter is made with an air channel underneath where a current of air is made
to flow constantly under the perforated floor which oxydises the charcoal and iron
turnings, and the oxydised charcoal and iron oxydises the sewage water and renders
it sufficiently pure for domestic and manufacturing purposes. I then take the pre-
cipitate from the tanks, and pump or lift it into deep settling tanks and continue to
draw off the supernatent water until the sludge is sufficiently stiff to be moulded into
bricks or lumps for drying, I then distill the dried sludge in close blast retorts under
high pressure and low temperature until all the ammonia and oil is distilled off, I then
force the uncondensed gases through a mixture of charcoal and peroxide of iron which
absorbs the sulphur, I then pass the gases through a vessel containing depurating
charcoal which causes a combination of part of the mixed gases and forms bicarbonate
of ammonia, The gases are then made to pass through a vessel containing ground
rock salt or chloride of sodium, and then through a saturated solution of chloride of
sodium which absorbs the bicarbonate of ammonia, and produces bicarbonate of soda,
and chloride of ammonium in solution, The remainder of the gases consisting chiefly

page_text: of hydrocarbons and nitrogen are conveyed to the boiler furnace and utilized in
evaporating the water. After all the gases have been discharged from the sludge
lumps in the retort under high pressure, I reduce the pressure in the retort and
increase the temperature and then calcine the risidue under high temperature which
converts the sludge lumps into powerful hydraulic cement, By the above continuous
process the sewage is thoroughly purified and the sludge is converted into valuable
commercial substances.
The novelty of this invention for purifying sewage and utilizing the precipitate does
not consist in adding and mixing the aforementioned substances, which have all been
used for mixing with sewage in some form or other before but the novelty consists,
First in the order or method of adding and mixing the aforementioned substances in
succession the one after the other in separate chambers as herein described, Second
in the novel method of utilizing the sewage sludge or precipitate, by manufacturing
Oil, Alkali, and cement from the said sludge, by distilling the sludge in close retorts
under high pressure and low temperature.
Referring to the drawings Fig. 1 is a plan of the mixing precipitating and filtering
tanks, Fig. 2 is a vertical section on the line X. Y. through the centre of the plan,
Fig. 3 is a vertical section of the screen wheel and part of the main sewer on the
line A, A', on plan. Fig. 4, is a transverse vertical section on the line Z, Z, The
main sewer enters the works at A on the plan and the sewage has to pass through the
screen wheel B, which is divided into six compartments by perforated plates which
intercepts the gross floating substances, and allows the liquid sewage to fall down
into the tank No. 1, as soon as one compartment of the wheel is filled the wheel is
turned round in the direction of the arrow one sixth by the winch C, which brings
an empty compartment under the lip of the sewer, as the wheel is turned round in the
direction of the arrow the solid substances are emptied on the floor W, and mixed
with dry ground chalk, clay, and coal dust, to be afterwards distilled to extract the oil
and ammonia, P is a retort for decomposing salt by heat and sulphuric acid; the
hydrochloric acid discharged from the salt is injected direct while it is hot into the
sewage chamber No. 1, where the sewage instantly absorbs the acid gas which com-
bines with the ammonia and discharges the sulphuretted hydrogen and carbonic acid
held in solution by the sewage. The hydrochloric acid also instantly and completely
disinfects the sewage by destroying the vitality of all germs therein contained. The
acidulated sewage and gases then pass under the dip stone V into chamber No. 2 into
which I inject sulphurous acid produced by burning sulphur or pyrites in the retort Q.
The sulphurous acid decomposes the sulphuretted hydrogen and deposits sulphur,
and the pentatheonic acid produced, is absorbed by the sewage along with the excess
of sulphurous acid; the sulphurous acid has the property of deodorizing and
decolorizing some of the matters contained in sewage. The sewage and gases then
pass under the dip stone V₁ and enter the chamber No. 3, where the unabsorbed gases
pass up the chimney S along with the hot furnace gases from the retorts. The
sewage then passes under the dip stone U into the chamber No. 4, where it meets
with a current of chlorine gas from the chlorine still R; the chlorine completes the
deodorization by coagulating the gelatin and mucus substances which are unaffected
by acids and alkalies. The sewage is now made to pass through the dash wheel D
which is divided into a number of combartments by perforated plates of iron, I fill
these compartments half full with a mixture of peroxide or sesquioxide of iron and
charcoal; the sewage on entering the wheel filters through the charcoal and iron
oxide the wheel keeps turning round in the direction of the arrows, and as one com-
partment dips into the sewage the opposite compartment rises out of the sewage, and
as the water drains out of the charcoal the air enters the pores and charges the
charcoal with oxygen to be again given off to the sewage, as the wheel keeps turning
round the oxide and charcoal is continually mixing and absorbing oxygen from the
air which is again mixed with the sewage and thoroughly oxydises it, The oxide of
iron and charcoal should be in pieces about the size of nuts, in the proportion of half
and half by measure, as the pieces keep wearing away, the compartments must be kept
constantly replenished with a fresh supply through openings in the side of the wheel

page_text: provided for that purpose. After the sewage has passed through the dash wheel D it
enters the compartments of a similar wheel E, the compartments of E are filled with
chalk and clay in the proportion of 3 of chalk to 1 of clay which mixes with the
sewage and absorbs the oil, grease, and salts of ammonia. The sewage after passing
through E enters a third dash wheel F, which is kept regularly supplied with a
mixture of coal dust and slaked lime in equal proportions the revolving of the wheel
thoroughly mixes the ingredients with the sewage. The caustic lime should be used
in sufficient quantity to neutralize the acidity of the sewage, after the sewage has
passed through the dash wheel F, it passes over a pair of crushing rollers G, where
the small lumps fall down between the rollers and are crushed into finer particles, the
manipulated sewage then passes through the sluice gates N, N³, into the precipitating
tanks H, H, If the sewage has not sufficient fall to drive the dash wheels D, E,
and F, they must be driven by an engine. The sewage water after it has precipitated
the solid matters in the tanks H, H, flows on to the filter beds I, I, which are com-
posed of charcoal, iron turnings and sand, a mixture of iron turnings and charcoal in
the proportion by measure of two of charcoal to one of iron turnings is spread about
one foot deep on a perforated iron floor or false bottom J¹, with an air space under it
communicating with the air shafts J and K. The charcoal and iron is covered with
clean sand to a depth of about 3 or 4 feet, any fine particles held in suspension by
the water are intercepted on the surface of the sand and any organic matter that
escapes oxydation in passing through the dash wheels become oxydized in passing
through the iron and charcoal powder in the filter. A current of air flows down the
shaft J and passes under the perforated floor and escapes up the shaft K. The charcoal
and iron turnings absorb oxygen from the air, and then gives off the oxygen to the
sewage in its passage through the filter. The purified water escapes from the filter
by the outfall drain L, and may be used for any purpose.. If it is intended to discharge
the effluent water into a river, there will be no necessity for filtering, because the
effluent water direct from the precipitating tanks would be purer than any river
water in the kingdom, If instead of using charcoal and iron turnings in the filter,
we were to use depurating charcoal, (manufactured by my patent process No. 956980)
in the filter, the filtered water would be made purer than any water delivered by the
London Water Companies. When the filter bed No. 1 is choked, the water is
turned into No. 2, and the surface of No. 1 filter is skimmed and the precipitate
in the tanks H H is discharged by the sluices O, O, into the receiving pits T, The
area of the filter beds ought not to be less than one superficial yard to every
620 gallons filtered in 24 hours, and the area of the precipitating tanks should be
equal to the area of the filter beds and from 5 to 6 feet deep, so that 300,000
gallons of sewage in 24 hours would require a filter of 480 superficial yards or
one tenth of an acre, so that the total area of precipitating tanks and filters required
for a town of 10,000 inhabitants would be at least 1920 superficial yards. The sludge
should be lifted from the pits T into deep settling tanks where the heavy sludge is
allowed to settle down and the supernatant water is drawn off from the top, the heavy
sludge is then drawn out of the bottom of the tank and moulded into bricks or lumps
for drying. The moulded sludge may be stacked in the open air to dry or artificial
heat may be used to dry the lumps. The dried lumps are then distilled in close
retorts under high pressure, to extract the oil and ammonia, and the residue is after-
wards calcined at a sufficient heat to convert it into cement. My patented retort and
condensing apparatus No. 95698 is a convenient apparatus for distilling the dried
sludge and extracting the oil and ammonia.
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;
1st. I claim the disinfecting of sewage by injecting hydrochloric acid gas hot from
the decomposition of salt into the crude sewage contained in suitable tanks therefor.
2nd. 1 claim the injecting of sulphurous acid gas into the disinfected sewage for
the purpose of decomposing the sulphuretted hydrogen and partially deodorizing and
decolorizing the aforesaid disinfected sewage.

page_text: .
3rd. I claim the injecting of chlorine gas into the disinfected and sulphured sewage
contained in a close chamber for the purpose of coagulating the gelatin contained in
the sewage.
4th. I claim agitating the disinfected sewage with charcoal and oxide of iron
contained in dash wheels for the purpose of oxydizing and completing the deodoriza-
tion of the sewage.
.
5th. I claim the mixing of the oxydized sewage with chalk and clay in a second
dash wheel for the purpose of absorbing the oil and grease contained in the sewage.
6th. I claim the mixing of the clayed sewage with coal dust and lime in a third
dash wheel for the purpose of neutralizing the acidity of the sewage.
7th. I claim filtering the supernatant water through a filter composed of charcoal
iron turnings and sand, laid on a perforated floor with an air space underneath where
a constant current of air is made to pass under the perforated floor.
8th. I claim the distilling of the dried precipitate in close retorts under high
pressure to extract the oil and ammonia, and calcining the residue to make cement.
9th. 1 claim the purification and utilization of sewage by performing the above
operations in consecutive order, in proper tanks and retorts, constructed and operated
substantially as herein described.