mprovements in the Purification of Sewage and other Foul Waters by the Employment of certain Waste Materials.
Year: 1891

page_text: Date of Application, 10th Nov., 1891
Complete Specification Left, 10th Aug., 1892-Accepted, 1st Oct., 1892
PROVISIONAL SPECIFICATION.
mprovements in the Purification of Sewage and other Foul Waters
by the Employment of certain Waste Materials.
I HAMOR LOCKWOOD of 7 Chapel Walks in the City of Manchester Contractor
do hereby declare the nature of this invention to be as follows:-
My invention consists of improvements in the purification of sewage and other
foul waters by the use of certain materials at present of no commercial value
produced in the treatment and manufacture of the light oils of tar and certain
shale and mineral oils in the manufacture of aniline, and in the distillation of
ammonia, in the manner hereinafter described, such process being in certain cases,
or under certain conditions supplemented by the addition of sulphuric acid in the
final stage.
The first material I use is the oil of vitriol which has been used in the washing
and purification of the light oils of tar or of mineral or shale oils. This vitriol is
contaminated with a considerable quantity of carburetted compounds and is known
among tar and oil distillers as acid tar.
The second material I employ is refuse borings, being the residue from the stills
in the reduction of nitrobenzol in the manufacture of aniline.
The third material I utilize in my process is ammonia still refuse, being the
residue left in the still in the commercial distillation of ammonia and being chiefly
an impure hydrate of lime.
I take the acid tar above described and put it into a lead or other acid resisting
tank, in which is an unperforated steam heating coil (preferably of lead) by means
of which I raise the temperature of the acid to 200° F. or thereabouts in order to
separate as far as possible the carburetted compounds, which to a large extent rise
to the top and must be skimmed off from time to time, as may be seen to be
necessary. If the temperature is kept constant at 200° F. forty eight hours is a
sufficient time for this operation, but a higher temperature will require a shorter
time and a lower temperature a longer time.
The liquor so purified I transfer to another acid resisting tank, but heated by a
perforated steam heating coil (preferably of lead) and I add to it from time to
time, the second material the refuse borings until more than sufficient to neutralise
the acid has been added. The temperature in this tank must be maintained
at 200° F. as the acid dissolving the iron forms an impure ferrous sulphate which
is most soluble at this temperature. In practice there is always a notable quantity
of ferric sulphate formed also. A scum rises in this operation which must be
skimmed off from time to time. For convenience in using I add water to this
solution until it contains 2450 grains of iron to the gallon when it is ready for use.
This I hereafter call the ferrous solution.
The third material the ammonia still refuse I put into an agitator and mix well
with water thus converting it into an impure milk of lime. When thoroughly
mixed it is ready for use.
Having thus obtained my ingredients I take of the ferrous solution and the milk
of lime, quantities in the proportions hereinafter ascertained and by any ordinary
mechanical arrangement of pipes and taps I regulate their quantity and add them
separately to the sewage or other foul water to be purified, the ferrous solution
first, but so that it may be quickly mixed with the milk of lime.
The sewage or other foul water thus treated is then at once conveyed to tanks
where it is allowed to rest as long as the nature of the accommodation will allow,
three hours being fairly satisfactory and twelve hours being as long as is at all

page_text: necessary so that the matter precipitated by action of the iron salt and lime on
themselves and on the sewage or other foul water treated may be able to subside.
After this time the resulting effluent will be found to be considerably purified
and may be allowed to run off and the precipitated sludge removed. If however
it is found that through incorrect proportions or want of time the effluent is not as
clear as it ought to be, or if it is found to be alkaline in the last tank on testing
with litmus paper or other chemical tests I add sulphuric acid in small quantities
from time to time till litmus paper or other chemical tests is not affected by it or
shows the slightest trace of acid.
Next as to the proportion of the iron solution and the milk of lime as between
themselves. This will depend on the amount of ferrous and ferric oxide in the one
and the hydrate of lime on the other and must be such that for each 28 grains of
iron, as ferrous oxide in solution these must be added so much of the milk of lime
as contains 28 grains of lime and for each 28 grains of iron as ferric oxide so much
milk of lime as will contain 42 grains of lime.
Then as to the amount to be added to the sewage or other foul water to be
treated. This will of course in the first instance have to be determined by
experiment in each individual case but as a general principal it may be taken that
other than the waste and the increased hardness of the water occasioned there is no
objection to using a reasonable excess of the iron solution and milk of lime provided
the proper proportion be maintained between the two. For an ordinary town
sewage where the water closet system is used and where there is little or no
manufacturing going on, for every gallon of sewage to be treated there should be
so much iron solution used as will contain about 5 grains of iron with milk of lime
containing available lime equivalent thereunto.
The iron solution can be prepared by the use of oil of vitriol obtained from any
ordinary source in acting on the iron borings already described or the oil of vitriol
obtained as already described may he made to act on iron or its oxides to produce
a salt of iron and such salt of iron could be used equally well with the impure milk
of lime already described or the salt of iron could be used equally well, with any
other form of quicklime hydrate of lime or other material as will supply the proper
proportion of available lime as above determined provided in such cases the
materials are each of them free from poisonous or otherwise deleterious or noxious
matters.
Dated this Ninth day of November 1891.
HAMOR LOCKWOOD.
COMPLETE SPECIFICATION.
Improvements in the Purification of Sewage and other Foul Waters
by the Employment of certain Waste Materials.
I, HAMOR LOCKWOOD, of Chapel Walks, Cross Street Manchester, Chemical
Manufacturer, 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 consists in improvements in the purification of sewage (in which
term as hereinafter used I include all foul waters of a like kind contaminated with
organic matters) by the use of certain materials at present of no commercial value
produced in the treatment and manufacture of the light oils of tar and certain
shale and mineral oils, in the manufacture of aniline, and in the distillation of
ammonia in the manner hereinafter described; such process being in certain cases
or under certain conditions supplemented by the addition of sulphuric acid in the
final stage.
The first material I use is the oil of vitriol which has been used in the washing
and purification of the light oils of tar or of mineral or shale oils. This vitriol is

page_text: contaminated with a considerable quantity of carburetted compounds and is known
amongst tar and oil distillers as acid tar.
The second material I use is refuse borings being the residue from the stills in
the reduction of nitrobenzol in the manufacture of aniline.
The third material I use is ammonia still refuse being the residue left in the
still in the commercial distillation of ammonia and being chiefly an impure hydrate
of lime.
I take the acid tar above described and put it into a lead or other acid resisting
tank in which is an imperforated steam heating coil (preferably of lead) by means
of which I raise the temperature of the acid to 200° Fahrenheit or thereabouts in
order to separate as far as possible the carburetted compounds which to a large
extent rise to the top and must be skimmed off from time to time as may be seen
to be necessary.
If the temperature is kept constant at 200° F. 48 hours is
a sufficient time for this operation but a higher temperature will require less and a
lower temperature more time.
The liquor so purified I transfer to another acid resisting tank heated by a
perforated steam heating coil (preferably of lead) and I add to it from time to
time the second material-the refuse borings-until more than sufficient to
neutralize the acid has been added. The temperature in this tank must be
maintained at 200° F. as the acid dissolving the iron forms an impure ferrous
sulphate which is most soluble at this temperature. In practice there is always a
certain quantity of ferric sulphate also.
A. scum rises in this operation which must be skimmed off from time to time.
For convenience in using I add water to this solution until it contains 2450 grains of
iron to the gallon when it is ready for use. This I hereafter call the ferrous
solution.
It must be understood that although I have described the use of these refuse
borings for producing the ferrous solution hereinafter referred to, I do not confine
myself to the same inasmuch as such ferrous solution may be made by the sub-
stitution of any convenient form of iron or its oxide in a divided condition for the
said refuse borings.
The third material-the ammonia still refuse-I put into an agitator and mix
well with water thus converting it into an impure milk of lime. When thoroughly
mixed it is ready for use.
Having thus obtained my ingredients, I take of the ferrous solution and, the milk
of lime, quantities in the proportions hereinafter ascertained, and by any ordinary
mechanical arrangement of pipes and taps I regulate their quantity and add them
separately to the sewage to be treated, the ferrous solution first, but so that it may
be quickly mixed with the milk of lime.
In practice I have found that by heating the milk of lime by means of super-
heated steam or in other convenient manner to a temperature of say 100° Fahr. or
as much higher as can be conveniently attained, the commercial value of the
process is much improved as thereby the precipitation is much accelerated and
practically rendered instantaneous.
The sewage thus treated is then at once conveyed to tanks where it is allowed to
rest as long as the nature of the accommodation will allow, three hours being fairly
satisfactory and twelve hours being as long as at all necessary, so that the matter
precipitated by the action of the iron salt and lime on themselves and on the
sewage treated may be able to subside. After this time the resulting effluent will
be found to be considerably purified and may be allowed to run off and the
precipitated sludge removed.
If however it is found that through incorrect proportions or want of time the effluent
is not as clear as it ought to be, or if on testing with litmus paper or other chemical
test it is found to be alkaline, in one of the later tanks I add sulphuric acid in
small quantities from time to time till litmus paper or other chemical test is not
affected by it or until it shows no trace of alkalinity, as I have discovered that it is

page_text: of great importance that the resulting fluid should not be alkaline as there is great
danger of subsequent decompositions of a noxious kind ensuing when such is the
case and it is an important part of my invention to prevent this by the addition of
sulphuric acid as above described.
Next as to the proportion of the ferrous solution and the milk of lime as between
themselves. This will depend on the amount of ferrous and ferric oxide in the one
and the hydrate of lime in the other and must be such that for each 28 grains of
iron as ferrous oxide in solution there must be added so much of the milk of lime
as will contain 28 grains of lime as hydrate, and for each 28 grains of iron as ferric
oxide so much milk of lime as will contain 42 grains of lime.
Then as to the amount to be added to the sewage to be treated. This will of
course in the first instance have to be determined by experiment in each individual
case but as a general principle it may be taken that other than the waste and the
increased hardness of water occasioned, there is no objection to using a reasonable
excess of the iron solution and milk of lime provided the proper proportions be
maintained between the two. For an ordinary town sewage where the water closet
system is used and when there is little or no manufacturing going on, for every gallon
of sewage to be treated there should be so much iron solution used as will contain
about 5 grains of iron with milk of lime in proportion in addition.
The ferrous solution can be prepared by the use of the oil of vitriol obtained
from any ordinary source acting on the iron borings or other forms of iron as
already described, but it would not possess the advantage of cheapness to so great
a degree a matter which is of great importance in the treatment of sewage and such
salt could be used equally well with the impure milk of lime already described, or
the salt of iron can be used equally well with any other form of quick lime,
hydrate of lime, or other material as will supply the proper proportion of available
lime as above determined, provided in such cases the materials are each of them
free from poisonous or otherwise deleterious or noxious matters. So also the
sulphuric acid which is used in the final stage as described will be equally efficacious
whether the ferrous solution be used in combination with the impure milk of lime
both obtained as described or whether substitutes be used for both or either of
them, so long as such substitutes furnish ferrous or ferric oxide, in conjunction with
available lime, and are otherwise free from noxious, poisonous or other deleterious
matters.
Having now particularly described and ascertained the nature of my inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. The use in the purification of sewage of a mixture of the ferrous solution with
the impure milk of lime herein described, supplemented when necessary by the
addition of sulphuric acid; substantially as described.
2. The use in the purification of sewage of a mixture of the ferrous solution
herein described, with hydrated lime, supplemented when necessary by the addition
of sulphuric acid; substantially as described.
3. In the purification of sewage by means of salts of iron and lime, the use of
sulphuric acid to render the resulting fluid neutral or acid; substantially as herein
described.
Dated this out
Ր .
1000
CHEESBROUGH & ROYSTON, Fels. Chart. Inst. P.A.,
15, Water Street, Liverpool, Applicant's Patent Agents.