A New and Improved Method for the Purification of Sewage and Waste Water from Manufacturing Processes.
Year: 1892

page_text: Date of Application, 8th Apr., 1892
Complete Specification Left, 7th Dec., 1892-Accepted, 28th Jan., 1893
PROVISIONAL SPECIFICATION.
A New and Improved Method for the Purification of Sewage and
Waste Water from Manufacturing Processes.
I, HARRY GRIMSHAW of 331 Ashton New Road, Clayton, Manchester, Chemical
Manufacturer, do hereby declare the nature of this invention to be as follows :-
I make use of the oxide of iron obtained in the manufacture of chloride of zinc,
during the process of purifying the same from the compounds of iron which exist
as an impurity in the chloride of zinc. I also make use of the waste oxide of iron
which is obtained as a bye product in the reduction of nitro benzol and similar
bodies in the manufacture of aniline and other dye producing substances.
To oxide of iron in either or both of the above forms, an equal quantity or there-
abouts of quicklime is added. A sufficient quantity of water is added to bring the
mixture into a proper consistency to be ground in an ordinary mortar mill or
similar appliance, and in such a mill the materials are ground until thoroughly
incorporated.
The mixture of oxide of iron & lime may be added at once to the sewage or
waste water, but it is preferable to keep the mixture for a few days before
so doing.
A suitable amount to add to ordinary sewage is about one ton to a million gallons,
but some descriptions of waste water will require considerably more than this
quantity.
If the waste water or sewage is alkaline a portion of the lime may be omitted.
In some cases where the sewage or waste water contains considerable quantities
of iron and alumina compounds, sulphuric or hydrochloric acid may be added to the
sewage or waste water, to bring the whole or a portion of these substances into
solution before the addition of the lime & oxide of iron mixture. In such cases
the proportion of iron in the mixture is diminished accordingly.
The impurities thrown down from the sewage or waste water are allowed to
subside in suitable tanks or receptacles & the clarified effluent is run off.
If it is required to obtain an effluent of great freedom from organic nitrogen, the
effluent is after subsidence in one or more tanks, treated with a small quantity, a
few grains per gallon, of ferric chloride or sulphate or of ferric oxychloride or
oxysulphate, or with a mixture of sulphuric or hydrochloric acid and nitrate of soda,
or with all or any of these substances. The nitrate of soda exerts an oxidizing
action on the organic matters in solution in a similar manner to manganate of soda &
thereby greatly purifies the effluent.
As a further means of purification or as a substitute for the latter portion of the
precipitation process, the effluent from the settling tanks may be passed through
a filter composed of either of the oxides of iron above specified, brought into a
suitable state of division and mixed with sand, gravel, coke, clinkers or other
suitable material.
Dad thin cech dan of Al 1000
HARRY GRIMSHAW.

page_text: COMPLETE SPECIFICATION.
A New and Improved Method for the Purification of Sewage and
Waste Water from Manufacturing Processes.
I, HARRY GRIMSHAW of 331 Ashton New Road, Clayton, 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 :-
I make use of the oxide of iron obtained in the manufacture of chloride of zinc
during the process of purifying the same from the compounds of iron which exist
as an impurity in the chloride of zinc, or alternately, of the oxide of iron which is
obtained as a bye-product in the reduction of nitro-benzol and similar bodies in
the manufacture of aniline and other dye producing substances.
I take of oxide of iron in either or both of the above named forms about an
equal quantity with quicklime. A sufficient quantity of water is added to bring
the mixture into a proper consistency to be ground in an ordinary mortar mill or
similar appliance, and in such a mill the materials are ground and thoroughly
incorporated.
The mixture of oxide or oxides of iron and lime may be added at once to the
sewage or waste water but it is preferable to keep the mixture for some days before
so doing. may alternatively, grind up the oxide of iron with water, and add the
lime to the sewage either before or after the oxide of iron or omit the lime, but I
do not consider the results so good as by previous grinding together of the oxide of
iron and the lime.
A suitable amount to add to ordinary sewage is about one ton of the iron &
lime mixture to each million gallons, but many descriptions of sewage & waste
water will require considerably more than this quantity.
If the sewage or waste water is neutral or alkaline a portion of the lime may
be omitted.
In some cases where the sewage or waste water contains considerable quantities
of iron and alumina compounds, sulphuric or hydro-chloric acid may be added to
the sewage or waste water to bring the whole or a portion of these bodies into
solution before the addition of the lime and iron mixture. In such cases the pro-
portion of iron in the mixture is diminished accordingly.
The solution of the above named iron and alumina compounds by means of the
acids is facilitated by the following procedure. The iron & alumina compounds
are generally in a'state of suspension in the sewage or waste water and by allowing
them to subside from the supernatant liquid they are obtamed in the more
concentrated form of a sludge which does not dilute the acids to same extent,
and the iron and alumina compounds are more easily dissolved. The iron and
alumina compounds thus dissolved in the hydrochloric or sulphuric acids may be
then added to such portions of the sewage or waste water as require a further
quantity of iron and alumina for perfect precipitation.
.
If it is required to obtain an effluent of great freedom from organic nitrogen,
the effluent after subsidence in one or more tanks, from the above named processes,
or some of them, is treated with a small quantity, say five to ten grains per gallon of
ferric chloride, ferric sulphate, ferric oxychloride, or ferric oxysulphate, or with a
mixture of sulphuric or hydro-chloric acid and nitrate of soda, or with all or any
of these substances.
The above named compounds of iron exert a clarifying influence on the
effluent & the nitrate of soda exerts an oxidizing action upon the organic matters
in solution in a somewhat similar manner to the well known manganates & per-
manganates of soda, and thereby further purifies the effluent.
As a further means of purification or as a substitute for the last portion of the
process, the effluent from the settling tanks may be passed through a filter bed,

page_text: composed of either or both of the oxides of iron hereinbefore specified, brought
into a suitable state of division, and mixed with sand, gravel, coke, clinkers, or
other suitable material.
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 general series & sequence of operations herein before described for the
precipitation and purification of sewage & waste water.
(2). The addition to sewage & waste water of the waste oxides of iron herein-
before specified with or without the addition of lime.
(3). The bringing into solution of the iron & alumina compounds of sewage or
waste water, by means of sulphuric or hydrochloric acid substantially as set forth,
so as to utilize them in the precipitation & purification of sewage & waste water.
(4). The addition of nitrate of soda to sewage, or waste water or to the effluent
from these, after precipitation & subsidence.
(5). The use of the waste oxides of iron, herein before specified, for the filtration
of sewage and waste water.
Dated the Fifth day of December 1892.
HARRY GRIMSHAW.