Improvements in Treating Sewage and other Impure or Waste Liquids for the Recovery and Manufacture therefrom of Manurial and other Products, and in Means or Apparatus therefor.
Year: 1886

page_text: Improvements in Treating Sewage and other Impure or Waste
Liquids for the Recovery and Manufacture therefrom of Manurial
and other Products, and in Means or Apparatus therefor.
I, WILLIAM HENRY HARTLAND of 115 Hydepark Street, in the City of Glasgow,
Industrial Chemist, do hereby declare the nature of this invention to be as follows:-
My invention relates to the treating of sewage discharged from distilleries and other
public works, town sewers and the like in order to recover therefrom products which are
or may be further treated for the manufacture of manures, cements and other com-
pounds the purification of the sewage in whole or in part resulting from the treatment.
In the early stages of treatment of the sewage I employ apparatus similar in kind to
that described in the Specification of Letters Patent No. 7958 of 1885 in passing
through which the matters carried in suspension are caused to subside, neutralisation
of the soluble and acid constituents and subsequent aeration of the partially purified
liquid take place, a further subsidence of suspended impurities is brought about and
finally absorption of the ammoniacal or other alkaline matters is effected, the whole
process being carried on continuously.
The sewage is led from the outfall of the town sewer or from the discharge pipe for
the sewage matters from public works directly into a large and deep subsidence tank
or pond having a sloping bottom and a recess or pocket at its lower end whereinto the
solid matters which subside trom the sewage tend to fall and wherefrom the sludge or
deposit may be periodically removed after disconnecting the tank from the sewer
outfall and pumping or draining off the supernatant fluid.
In one of the walls of the subsidence tank an outlet is formed near the normal
.

page_text: water level so that that portion of the liquid near the surface from which the
impurities have been deposited alone passes off. The outflowing liquid enters a
neutralising tank wherein is fitted a box or a series of boxes or open frames loosely
packed with limestone chalk or other material adapted to neutralise acid and other
soluble matters in the sewage under treatment, such boxes or frames of neutralising
material being fitted to extend from top to bottom of the tank and across its whole
breadth in order that the liquid passing through it from the subsidence tank may be
intercepted and acted on by the neutraliser employed. At the lower end of the
neutralising tank is a doorway communicating with the subsidence tank but which is
normally closed by means of a sliding door or a valve and is only opened when
cleaning out the tanks in order that the sludge or slime deposited in the neutralising
tank may be allowed to drop or be washed into the subsidence tank for removal with
the deposit contained therein. From the neutralising tank the partially purified liquid
is discharged through a perforated screen or a number of perforated screens in a close
tank through which air is blown in order to oxidise organic and other matters in the
liquid which falls through the air in the form of fine spray the power for operating
the blowing apparatus being obtained when available from the fall of the liquid itself.
After aeration the liquid flows into a second subsidence tank wherein are deposited
the organic and other impurities which have been oxidised, and thence the liquid flows
out by an opening near the water level into a tank or canal in which are placed a series
of boxes or frames similar to the neutralising frames but containing charred vegetable
matters and loose rubbish adapted to absorb the ammonia and similar matters of
manurial value contained in the liquid.
Precipitation of the impurities in the sewage in the subsidence tanks may be
facilitated by discharging thereinto lime, sulphate of alumina or similar reagents in
common use for effecting precipitation of sewage matters the reagent employed being
that best adapted for use with the particular kind of sewage under treatment, and
depending largely upon the use to be made of the precipitant. The material deposited
in the subsidence tanks is removed periodically, the sewage from the outfall or discharge
pipe being in the interval directed through a duplicate apparatus, and the semi-liquid
matter is or may be treated in separate tanks into which it is pumped or otherwise
raised in order to effect as nearly as possible complete precipitation.
Thereafter the solid constituents are subjected to treatment varying with the nature
of the material and as hereinafter set forth. In dealing with focal matter for
example the material is after precipitation by use of lime defecated and burnt to
form a product of bigh manurial value consisting largely of phosphate of lime.
In dealing with town's sewage the material removed from the subsidence tanks
or the precipitation tanks, and the deposit formed in the neutralising and aerating
chambers may be mixed together and used as a manure, but in general it will be
advantageous to use the deposit from the various tanks or chambers separately and
mix them with such constituents as are required to form with them useful manures.
The material in the absorption boxes after a time becomes highly charged with
ammonia and is of itself of high value as manure.
On removal of the sedimentary products of the sewage from the tanks or chambers
wherein they are deposited, I in some cases subject these products to a process of
drying and thereafter mix with the dried material varying proportions of sulphate
or nitrate of ammonia, bone dust and similar matters adapted to increase the manurial
value of the products formed.
For the manufacture of cement the liquid after settling is roughly filtered through
natural chalk, which by affinity will absorb phosphoric and sulphuric acid by contact
with sewage, the chalk after being charged with acid may then be ground to a slurry,
dried and manufactured in the ordinary way, or as a cheaper process it may on
account of the acidity it contains be reduced to a clinker under a forced pressure of
air in an ordinary furnace similar in construction to a puddling furnace, the waste
heat of the process being employed to beat the floors underground on which the sludge
and other materials are dried previously to burning.
For the manufacture of manure, (exclusive of ordinary sludge) the charred

page_text: earthy or vegetable filtrate is taken from the second section of the apparatus in
combination with the deposit formed after aeration, the whole being mixed together
and then dried, and if old lime or plaster rubbish is used in place of chalk for
neutralising the liquid it is also incorporated in or about the following proportions:
In the manufacture of manure, (including the ordinary sludge) the proportions may
be as follows:-
Earthy or Vegetable Matter
Dissolved Bones
Phosphorised Lime
Nitrate of Soda
Sulphate Ammonia
Sludge burnt to an ash
1500 parts.
240 parts.
240 parts.
36 parts.
37 parts.
187 parts.
In order to manufacture a superphosphate manure I reverse the proportions of earthy
matters and burnt sludge.
In order to dispose of sludge from town sewage and make it available for manure at
slight cost 1 adopt the following means.
When the deposit obtained as described in the purification apparatus requires
removal the raw sewage is directed through a duplicate tank, the tank full of deposit
being cut off from the apparatus by valves, the sludge and liquid is then discharged
by gravitation or otherwise to a tank, a second tank being provided for the deposit
obtained from the second section of the apparatus, these two tanks are connected with
a divided invert which is situated in the centre of a group of upcast shafts when the
works are on a large scale. At some distance above the invert bottom I form a floor
or room within the central shaft. On the floor I place the upper part of a chain
pump or elevator which raises the sludge or other deposit to this level from which it
gravitates down a pipe or run. A certain distance from the pump discharge I place
a vessel on the run and from it discharge into the sludge, Sulphate of iron in liquid.
The sludge then drops to a lower level to produce thorough admixture. The liquid
then is mixed with quick lime by means of devices such as are described as applied for
this purpose in my specification No. 7958 of 1885, and then enters a tank where precipi-
tation takes place. In order to remove as much moisture as possible, I at the opposite
end of the tank employ a rising and falling sluice or valve to the upper side of which
is attached a pipe or trap, by means of a tap this pipe carries off the supernatant
liquid which is then conveyed to the neutralising tank of the purifying apparatus for
recovery of the soluble matters by aeration.
When the sludge is sufficiently freed of moisture I by means of a screw valve in
the bottom of the precipitating tank discharge on to a drying floor situated beneath.
The drying floor is formed of flues and covered with brick or concrete, the drying
operation being effected by the waste heat obtained both from the steam boilers used
to operate the aeration current or the sludge pumps, and the like and from kilns used
in the process of cement manufacture when such is carried ou and lastly from the
kilns used for burning the dried sludge to an ash. Generally the drying floors are
under the ground surface and form practically the floor of a large flue, one end com-
municating by doors with the open air and the other with an upcast shaft which
carries off not only the heat from the flues but also the odours evolved by the sludge
during the drying process. Generally the drying floor would be covered a certain
depth with refuse coal and ashes or other suitable material to facilitate drying and
absorb odour and by forming fuel to reduce the cost of burning the sludge to
an ash.

page_text: For the purification of manufacturing liquid and recovery of waste products I use
the apparatus described and vary the treatment required by the particular liquid to be
dealt with in the following way. In the case of a liquid containing ferrous salts in
solution with acid as in galvanizing liquid, for instance, I first settle the liquid and
then roughly pass it through burnt chalk and then agitate it violently by aeration
under pressure which frees the gases and allows of the subsidence of the soluble salt,
leaving the liquid a simple acid solution which I then neutralize in the usual way by
bringing it in contact again with chalk.
In treating the metallic liquid resulting from copper works and the like, I aerate
with very cold air which leads to a deposit of iron and other matters on subsidence,
and again violently agitate and aerate with cold air, which leads to a deposit of
sulphate of soda or salt cake.
For alkaline liquids from paper works, soap works and the like I use the same
routine as for town sewage, the filtrate in both sections being charred earthy matter,
and in some cases I would use as a precipitant about two grains of protochloride of
iron and two grains of lime in solution and afterwards aerate the liquid to deposit
matter held in solution.
In dealing with sulphurous liquid I settle and pass through burnt chalk and then
aerate and afterwards pass through animal charcoal which leads to deposition, leaving
the liquid but slightly colored and free from odour.
For liquids containing albuminous matter such as distillery liquid and brewery
liquid and the like, I in the case of raw grain distillery liquid first settle the liquid for
deposition of the suspended matter which may then be dried or cooled as at present
as a sediment for cattle food but to make it more valuable I first dry it on a heated
floor after which it may be ground or pressed into cakes and sold for cattle food.
The finer organic and soluble matter I then agitate and aerate with very cold air,
and after settling it is filtered through charred peat, 'the deposited matter after aeration
and the filtrate being mixed together and form a valuable artificial manure suitable
for fertilizing grain crops.
I sometimes precipitate the soluble matter after the recovery of the suspended
matter has taken place by means of per-chloride of iron & lime in solution. The
reaction forms a sesquioxide of iron and the precipitate is rich in nitrogen and
phosphoric acid and inay be used mixed with peat and dried to form a valuable
artifical manure.
Dated this Seventh day of December 1886

page_text: improvements in Treating Sewage and other Impure or Waste
Liquids for the Recovery and Manufacture therefrom of Manurial
and other Products, and in Means or Apparatus therefor.
I, WILLIAM HENRY HARTLAND of 115 Hydepark Street, in the City of Glasgow,
Industrial 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 :-
My invention relates to the treating of sewage discharged from distilleries and
other public works, town sewers and the like in order to recover therefrom products
which are or may be further treated for the manufacture of manures, cements and
other compounds, the purifications of the sewage in whole or in part resulting from
the treatment. In the early stages of treatment of the sewage I employ apparatus
similar in kind to that described in the Specification of Letters Patent Number 7958
of 1885 in passing through which the matters carried in suspension are caused to
subside, neutralization of the soluble and acid constituents and subsequent aeration
of the partially purified liquid take place, a further subsidence of suspended impurities
is brought about and finally absorption of the ammoniacal or other alkaline matters is
effected, the whole process being carried on continuously.
The sewage is led from the outfall of the town sewer or from the discharge pipe
for the sewage matters from public works directly into a large and deep subsidence
tank or pond having a sloping bottom and a recess or pocket at its lower end where-
into the solid inatters which subside from the sewage tend to fall and wherefrom the
sludge or deposit may be periodically removed after disconnecting the tank from the
sewer outfall and pumping or draining off the supernatant fluid.
In one of the walls of the subsidence tank an outlet is formed near the normal
water level so that that portion of the liquid near the surface from which the
impurities have been deposited alone passes off. The outflowing liquid enters a
neutralising tank wherein is fittec a box or a series of boxes or open frames loosely
packed with limestone, chalk or other material adapted to neutralise acid in the
sewage under treatment, such boxes or frames of neutralising material being fitted to
extend from top to bottom of the tank and across its whole breadth in order that the
liquid passing through it from the subsidence tank may be intercepted and acted on
by the neutralizer employed. At the lower end of the neutralising tank is a doorway
communicating with the subsidence tank but which is normally closed by means of a
sliding door or a valve and is only opened when cleaning out the tanks in order that
the sludge or slime deposited in the neutralising tank may be allowed to drop or be
washed into the subsidence tank for removal with the deposit contained therein.
From the neutralising tank the partially purified liquid is discharged through a
perforated screen or a number of perforated screens in a close tank through which air
is blown in order to oxidise organic and other matters in the liquid which falls
through the air in the form of fine spray the power for operating the blowing

page_text: After
apparatus being obtained when available from the fall of the liquid itself.
aeration the liquid flows into a second subsidence tank wherein are deposited the
organic and other impurities which have been oxidised and thence the liquid flows
out by an opening near the water level into a tank or canal in which are placed a
series of boxes or frames similar to the neutualising frames but containing charred
vegetable matters and loose rubbish adapted to absorb the ammonia and similar
matters of manurial value contained in the liquid. Gravitation being the motive
power of the system the effect is that the partially purified sewage of the first section is
discharged as an effluent at about the same level at which the raw sewage enters the
apparatus, whilst the purified and oxidised effluent of the second section is discharged
at the same level as the first less the vertical drop from 2 to 4 feet for aeration
between the two sections, the effect being to much reduce the cost of pumping, to
obviate tidal or other impounding influences, whilst the liquid to be pumped in this
case is the purified effluent only, in place of pumping raw sewage by ordinary means,
the system of apparatus being practically a part of or continuation of the sewers and
forming their outfall.
Precipitation of the impurities in the sewage in the subsidence tanks may be
facilitated by discharging thereinto lime, sulphate of alumina or similar reagents in
common use for effecting precipitation of sewage matters the reagent employed
being that best adapted for use with the particular kind of sewage under treatment,
and depending largely upon the use to be made of the precipitant. In some cases
and especially when the sludge recovered in the first tank is sent out to sea or other-
wise disposed of by ordinary means, I precipitate the other deposits to remove water
by adding basic slag ground to a very fine powder in quantities varying from 2 to 10
per cent of the estimated solid products contained in the liquid sludge. The effect is
to largely enrich the sludge with phosphoric acid, the quantity varying accordingly
as the manure may be required for fertilizing a cereal or root crop. The object of
the purification apparatus is for the separation of the suspended from the soluble
matters contained in sewage and division of the former into two separate deposits
and to effect in the latter a transmutation of Nitrogen as it exists in the volatile
matters of sewage, into Nitrates and for recovery of this constituent of sewage in
combination with such materials as would form manure in mixture with the various
deposits recovered by the process as described hereafter.
The sewage in its passage through the first tank of the first section quickly deposits
the heavy suspended matter such as results from road and other surface drainage ;
whilst the lighter and more volatile suspended matter is passed into the second tank
containing the neutralizing frames filled with chalk or other lime material, the process
of the first section freeing the liquid from suspended matter and dividing the ordinary
sludge into two separate deposits possessing different degrees of specific gravity and
manurial value; or a deposit of road and other surface detritus in the first tank and
a deposit consisting almost wholly of the sewage sludge proper in the second.
The sewage after treatment as described still contains the volatile and soluble
matter and this is then aerated or naturally oxidized by falling through a perforated
plate on to a double screen formed of wire netting which divide it into spray through
which air is blown or forced either mechanically or by means of draught or ventilation,
in some cases the process effecting both aeration and agitation which puts into
practical operation the chemical law whereby compounds of Nitrates or Nitric Acid
are formed spontaneously by the contact of air with decomposing animal or vegetable
matter containing Nitrogen, the necessary base to combine with the acid so formed in
a continuous manner being provided by the Carbonate or Hydrate of Lime taken up
by the sewage in its passage through the neutralising boxes of the first section previous
to aeration taking place. The settling tank and filter tank of the second section being
provided, the first for subsidence of a portion of the oxidized matter which by oxidation
attains sufficient gravity to subside in its passage through the tank whilst the filtration
materials of the last or second tank of the second section are designed to take up and
absorb by affinity the Ammoniacal and Nitrogenous constituents which have been
developed and created by the process described.

page_text: The material deposited in the subsidence tanks is removed periodically the
sewage from the outfall or discharge pipe being in the interval directed through a
duplicate apparatus and the semi-liquid matter is or may be treated in separate tanks
into which it is pumped or otherwise raised in order to effect as nearly as possible
complete precipitation. Thereafter the solid constituents are subjected to treatment
varying with the nature of the material and as hereinafter set forth. In dealing with
foecal matter for example the material is after precipitation by use of lime defecated
and burnt to form a product of high manurial value consisting largely of phosphate of
lime.
In dealing with town's sewage the material removed from the subsidence tanks or
the precipitation tanks, and the deposit formed in the neutralizing and aerating
chambers may be mixed together and used as a manure but in general it will be
advantageous to use the deposit from the various tanks or chambers separately and
mix them with such constituents as are required to form with them useful manures.
The material in the absorption boxes after a time becomes highly charged with
ammonia and is of itself of high value as manure.
On removal of the sedimentary products of the sewage from the tanks or chambers
wherein they are deposited, I in some cases subject these products to a process of
drying and thereafter mix with the dried material varying proportions of sulphate or
nitrate of ammonia, bone dust and similar matters adapted to increase the manurial
value of the products formed.
For the manufacture of cement the liquid after settling is roughly filtered through
natural chalk, which by chemical affinity will absorb phoshoric and sulphuric acid by
contact with sewage. The chalk, after being charged with acid may then be ground
to a slurry, dried and manufactured in the ordinary way or as a cheaper process it
may on account of the acidity it contains be reduced to a clinker under a forced
pressure of air in an ordinary furnace similar in construction to a puddling furnace,
the waste heat of the process being employed to heat the floors underground on which
the sludge and other materials are dried previous to burning.
For the manufacture of manure (exclusive of ordinary sludge) the charred earthy
or vegetable filtering material is taken from the second section of the apparatus in
combination with the deposit formed after aeration and the deposit from the second
tank of the first section the whole being mixed together and then dried, and if old
lime or plaster rubbish is used in place of chalk for neutralising the liquid it is also
incorporated in or about the following proportions:
Deposits and Earthy or Vegetable Matter
Dissolved Bones
Phosphorised Lime
Nitrate of Soda
-
Sulphate of Ammonia
-
1687 parts
-
240 parts
240 parts
40 parts
-
33 parts.
In the manufacture of manure (including the ordinary sludge) the proportions may
be as follows:-
Deposits and Earthy or Vegetable Matter
Dissolved Bones
Phosphorised Lime
Nitrate of Soda
Sulphate of Ammonia
Sludge burnt to an ash
-
1500 parts
-
240 parts
240 parts
36 parts
37 parts
187 parts.
In order to manufacture a superphosphate manure 1 reverse the proportions of earthy
matters and burnt sludge

page_text: by gravitation or otherwise to a tank, a second tank being provided for the
deposit obtained from the second section of the apparatus when on a small scale; but
in the case of large quantities as indicated in sectional elevation at figure 1 and in
horizontal sections at figures 2 and 3 of the annexed drawings the tanks are connected
with a sludge well, tank or invert B which is situated in the centre of a group of
upcast shafts C.
At some distance above the bottom of the well I form a floor or
room D within the central shaft. On the floor I place the upper part of a chain
pump or elevator E which raises the sludge or other deposit to this level from which
it gravitates down a pipe or run F. A certain distance from the pump discharge I
place a vessel G on the run and from it discharge into the sludge, Sulphate of iron in
liquid. The sludge then drops to a lower level at H to produce thorough admixture.
The liquid then is mixed with quick lime by means of devices I such as are described
as applied for this purpose in my Specification Number 7958 of 1885 and then enters
a tank J where precipitation takes place. In order to remove as much moisture as
possible, I at the opposite end of the tank employ a rising and falling sluice or
valve K to the upper side of which is attached a pipe or trap. By means of a tap this
pipe carries off the supernatant liquid which is then conveyed to the neutralising tank
of the purifying apparatus for recovery of the soluble matters by aeration.
When the sludge is sufficiently freed of moisture I, by means of a screw valve Lin
the bottom of the precipitating tank, discharge on to a drying floor M. situated
beneath. The drying floor is formed of flues N and covered with brick or concrete,
the drying operation being effected by the waste heat obtained both from the steam
boilers O, used to operate the aeration current or the sludge pumps and the like and
from kilns used in the process of cement manufacture when such is carried on and
lastly from the kilns P used for burning the dried sludge to an ash. Generally the
drying floors are under the ground surface and form practically the floor of a large
flue, one end communicating by doors with the open air and the other with the upcast
shaft which carries off not only the heat from the flues but also the odours evolved
by the sludge during the drying process. The upcast shafts or ventilating tower may
also be employed in combination with the forced aerated current for ventilating and
removal of gases from the intercepting or other sewers supplying the system with
sewage, the current of air being conveyed from the aeration apparatus to the upper
part of the sewer Q to force the gases in the direction of the upcast shaft through a
pipe connection R between the two, the operation of drawing of these heavy gases
and delivering them at a safe height in the atmosphere being greatly facilitated by the
atmospherical vacuum created by the heated or dry air resulting from the sludge
drying and burning operations described, the effect as a whole tending to exert a
syphonage or after draft on the system of sewers beyond the point at which the
aerating currents are introduced; and as the operation would be continuous and
automatic the result would be to largely reduce the volume of sewer gases and avoid
danger to public health thereby. Generally the drying floor would be covered a
certain depth with refuse coal and ashes or other suitable material to facilitate drying
and absorb odour and by forming fuel to reduce the cost of burning the sludge to
an ash.
For the purification of manufacturing liquid and recovery of waste products I use
the apparatus described and vary the treatment required by the particular liquid to be
dealt with in the following way. In the case of a liquid containing ferrous salts in
solution with acid as in galvanizing liquid for instance, I first settle the liquid and
then roughly pass it through burnt chalk placed in neutralizing boxes and then agitate
it violently with air under pressure which frees the gases and allows of the subsidence
of the soluble salt, leaving the liquid a simple acid solution which I then neutralize in
the usual way by bringing it in contact again with raw lime or chalk placed in a
conduit or by means of a series of neutralizing boxes as above described.
In treating the metallic liquid resulting from copper works and the like, I aerate
with very cold air which leads to a deposit of iron and other matters on subsidence,
and again violently agitate and aerate with cold air which leads to a deposit of sulphate
of soda or salt cake.

page_text: For alkaline liquids from paper works, soap works and the like, I use the same
routine as for town sewage the filtering material in both sections being charred earthy
matter, and in some cases I would use as a precipitant about two grains of lime and
about two grains of protochloride of iron in solution and afterwards aerate the
liquid to deposit matter held in solution.
In dealing with sulphurous liquid I settle and pass through burnt chalk and then
aerate and afterwards pass through animal charcoal which leads to deposition, leaving
the liquid but slightly colored and free from odour.
For liquids containing albuminous matter such as distillery liquid and brewery
liquid and the like I in the case of raw grain distillery liquid first settle the liquid for
deposition of the suspended matter which may then be dried or cooled as at present
as a sediment for cattle food but to make it more valuable I first dry it on a heated
floor after which it may be ground or pressed into cakes and sold for cattle food. The
finer organic and soluble matter I then agitate and aerate with very cold air and after
settling it is filtered through charred peat the deposited matter after aeration and the
filtrate being mixed together to form a valuable artificial manure suitable for fertilizing
grain crops.
I sometimes precipitate the soluble matter in the albuminous liquor after the recovery
of the suspended matter has taken place by means of per-chloride of iron and lime in
solution. The reaction forms a sesquioxide of iron and the precipitate is rich in
nitrogen and phosphoric acid and may be used mixed with peat and dried to form a
valuable artificial manure.
In the case of sewage resulting from operations carried on in skin works Tanneries
and the like, and of similar liquid which usually contain large quantities of potash in
solution, the liue process of the second tank of the first section may be omitted as the
potash provides a sufficient base to take up and combine with the Nitrates produced by
the process of aeration as described.
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 improved means for treating sewage for the recovery therefrom of manurial
and other matters substantially as herein set forth.
2. The process of treating sewage and impure liquids resulting from manufacturing
operations consisting in passing the liquid through tanks adapted to effect the deposit
of sludge, neutralizing acid and other soluble constituents, and oxidising the
organic matters in the partially purified liquid by aeration, the several operations
being carried on continuously and by means substantially such as described.
3. The production of manurial compositions substantially as described from
matters recovered in the process of purifying sewage and other impure liquids.
Dated this Sixth day of September 1887.