Improvements in the Oxidation of Sewage and Impure Waters, and of Material for use in the Treatment of such Sewage and Impure Waters.
Year: 1891

page_text: Date of Application, 11th Sept., 1891
Complete Specification Left, 11th June, 1892-Accepted, 16th July, 1892
PROVISIONAL SPECIFICATION.
Improvements in the Oxidation of Sewage and Impure Waters, and
of Material for use in the Treatment of such Sewage and Impure
Waters.
I FRANK PULLEN CANDY of 56 Nightingale Lane Balham in the County of
Surrey Sanitary Engineer do hereby declare the nature of this invention to be as
follows:-
:-
My invention relates to improvements in the oxidation of ferrous salts, or other
like salts applicable to the treatment of sewage and impure waters by bringing such
salts into contact with a manganic oxide preferably the black dioxide hydrated
ferric oxide or other similar oxydizing material. By preference I use the salt in
a solution, and add to the solution sufficient acid to enable the conversion to the
higher state of oxidation required to take place. This solution is brought into
direct contact with manganic oxide, hydrated ferric oxide or similar material.
The contact may be effected in any convenient manner for instance by agitation in
a revolving cylinder. The treated salt is then a valuable material for use in the
oxidation and precipitation of sewage and impure waters. In some cases and
particularly to facilitate transport I might evaporate the aforesaid prepared solution
and use the residual product in the treatment or precipitating and oxidizing of
sewage and impure waters. I may effect the oxidation of such sewage and impure
waters by bringing them into direct contact with the manganic oxide or hydrated
ferric oxide in any convenient manner.
Dated this 10th day of September 1891.
DUTTON & FULTON,
1, St. James Square, Manchester, Agents.
COMPLETE SPECIFICATION.
Improvements in the Oxidation of Sewage and Impure Waters, and
of Material for use in the Treatment of such Sewage and Impure
Waters.
I, FRANK PULLEN CANDY of 56 Nightingale Lane, Balham in the County of
Surrey, Sanitary 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:-
My invention relates to improvements in the oxidation of ferrous salts and consists
in bringing such salts into contact with manganese dioxide or with hydrated ferric
oxide, whereby the ferrous salts are oxidized and a valuable precipitating and
oxidizing agent for sewage and impure waters is obtained. When I use hydrated
ferric oxide as the oxidizing agent I preferably employ that kind known as
bog ore.
can bring the ferrous salt into contact with the manganese dioxide or hydrated
ferric oxide in a variety of ways. The ferrous salts I use are the ferrous sulphate
and the ferrous chloride, these can be cheaply obtained as waste liquors from tin
plate workers, galvanizers and other works.
I take a solution of the ferrous salts, preferably a solution containing about two
or three pounds avoirdupois of the crystalline salt to each gallon of solution (by
preference I use this solution warm) and I add to it about fifteen per centum, by
weight of the crystalline salt, of absolute sulphuric or hydrochloric acid or its
equivalent in commercial acid, and bring this acidified solution into contact with
the manganese dioxide or the hydrated ferric oxide, for example I place the

page_text: acidified solution in a cylinder or box similar to a churn, I also place in the cylinder
or box about three times as many pounds avoirdupois of one, or both, of the before-
mentioned oxidizing materials, as there are gallons of the ferrous salt solution, the
cylinder and its contents are then slowly caused to revolve so as to bring the whole
of the solution into contact with the oxidizing agent; when the colour of the
solution has changed from a pale green to a reddish brown, which would be after
about twenty minutes agitation of the cylinder and its contents when manganese
dioxide is used, the manufacture is complete and the oxidized solution is run from
the churn and stored or run direct into the sewage or polluted water; the quantity
necessary to effect precipitation of the sewage varies with such sewage or polluted
water, but as a rule a quantity of oxidized solution containing originally from two
to fourteen grains of the crystalline ferrous salt, is sufficient to be added to each
gallon of sewage or polluted water to be treated.
The time necessary for the oxidation of the solution varies with the relative
quantity of oxidizing material with which the solution is brought into contact, the
greater the relative quantity of oxidizing material the less time is required for
oxidation. A greater time for contact is required when hydrated ferric oxide is
used than when manganese dioxide is employed. During the process of oxidation
a certain amount of the oxidizing material is used up. This has to be replaced by
fresh material from time to time, in the case of manganese dioxide, about
eight per centum to ten per centum by weight of the crystalline salt in the solution,
is used up; for instance in oxidizing a solution containing 100 pounds of crystalline
ferrous sulphate, eight to ten pounds of manganese dioxide would be used up and
also about twenty pounds of commercial sulphuric acid of specific gravity of
about 1.70.
I sometimes also place ground "bauxite" in the cylinder together with the
beforementioned solution and material, adding a sufficient quantity of sulphuric
acid to convert the bauxite into aluminium sulphate.
Instead of bringing the acidified solution of ferrous sulphate or ferrous chloride
into contact with the oxidizing material by agitation in a revolving cylinder or
box, I sometimes form the manganese dioxide or hydrated ferric oxide into a
filter by placing it in a receptacle and allowing the acidified ferrous salt solution to
filter therethrough, whereby it becomes oxidized, the speed of filtration and
consequently the amount of oxidation of the solution is regulated by a tap at the
outlet, as the oxidizing material is used up it is replaced by fresh and the filters
are cleaned as often as necessary; when I employ manganese dioxide in the filter
I use it preferably in granules about the size of peas; after such filter has been
in use for about a day the oxygen has been abstracted from the surfaces of these
granules of the manganese dioxide and a yellowish or reddish layer is left on the
surfaces; this layer impedes the process of oxidation but can be easily removed
by washing and can be subsequently recovered by deposition in the form of
a powder, this powder contains manganese and can be recovered and utilized for
various purposes. Or I take the crystallised ferrous salt and add to it about
five per centum to eight per centum of dioxide of manganese preferably in fine
powder and reduce this to a thick slurry by grinding in a machine, with or without
the addition of a little hot or cold water, and then add about fifteen per centum by
weight of the crystalline salt, of absolute sulphuric or hydrochloric acid or its
equivalent in commercial acid. The whole mass is then well mixed and allowed
to set when it is ready for use; or I similarly reduce the ferrous salt to a slurry,
add about fifteen per centum to twenty per centum of its weight of hydrated ferric
oxide, and then acidify as before, well agitate the whole and leave to set, it must
not, however, be allowed to set quickly as the action of the hydrated ferric oxide
is slower than that of manganese dioxide. I do not limit myself to the percentage
of acid mentioned that is to say to fifteen per centum by weight of the crystalline
salt, of absolute acid or its equivalent in commercial acid (by absolute acid I mean
that which corresponds to the theoretical formula H,O, SO, and HCI). I some
times use acid equivalent to twenty per centum of absolute acid and sometimes use

page_text: acid equivalent to less than fifteen per centum of absolute acid, the action of the
oxidized ferrous salt on sewage or impure water is correspondingly more powerful
with a greater percentage of acid up to about twenty per centum of absolute acid,
but I find that acid equivalent to about fifteen per centum of absolute acid gives the
best results in practice.
I would have it understood that I always work with an excess of the oxidizing
material when oxidizing a solution at the ferrous salt, and that I generally use
sulphuric acid for acidifying the ferrous sulphate solution and hydrochloric acid for
acidifying the ferrous chloride solution. I sometimes use the manganese dioxide
combined with the hydrated ferric oxide. It will be evident that other ways
than those I have mentioned may be devised for bringing the ferrous salt into
contact with the manganese dioxide or hydrated ferric oxide and I do not
limit myself to the particular ways mentioned. I do not find it necessary to
oxidize the whole of the ferrous sulphate or ferrous chloride, but prefer to
oxidize only from fifty to eighty per centum of such ferrous salt leaving the remaining
fifty per centum to twenty per centum of ferrous salt unoxidized.
I sometimes oxidize the sewage or polluted water by bringing it into contact with
the manganese dioxide for instance by passing the sewage or polluted water through
a layer of the manganese dioxide in granules preferably about the size of peas, in
the same manner as charcoal would be employed, the layer being cleaned as often
as necessary; or by agitating the manganese dioxide with the sewage or polluted
water in a revolving chamber or cylinder, the greater the degree of purification
required the longer must the sewage or polluted water be brought into contact with
the manganese dioxide, in ordinary cases a contact of about five minutes of each
drop of water with the manganese dioxide is sufficient.
When the manganese
dioxide is worn out it is replaced by fresh. It is evident I may bring the
Bewage or polluted waters into contact with the manganese dioxide in various
other ways.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is:
1. The manufacture of a precipitant and oxidizer for sewage and impure waters
by the oxidation of ferrous sulphate or ferrous chloride, the oxidation being obtained
by bringing such solution into contact with manganese dioxide or hydrated ferric
oxide substantially as herein described.
2. The manufacture of a precipitant and oxidizer for sewage and impure waters
by the oxidation of an acid solution of ferrous sulphate or ferrous chloride, the
oxidation being obtained by bringing such acid solution into contact with manganese
dioxide.
3. The manufacture of a precipitant and oxidizer for sewage and impure waters
by the oxidation of an acid solution of ferrous sulphate or ferrous chloride, the
oxidation being obtained by bringing such acid solution into contact with hydrated
ferric oxide.
4. The oxidation of sewage and impure waters by bringing such sewage or
impure waters into contact with manganese dioxide substantially as herein
described.
5. The oxidation of sewage and impure waters by bringing such sewage or impure
waters into contact with manganese dioxide.
Dated this 10th dow of Inne 1800