AN IMPROVED METHOD OF PURIFYING WATER CONTAMINATED BY DISSOLVED VEGETABLE MATTER
Year: 1884

page_text: I, ALEXANDER IRVING, of Wellington College, Wokingham, and Senior Science-
Master in the said Wellington College, Clerk in Holy Orders, do hereby declaro
the nature of my invention for AN IMPROVED METHOD OF PURIFYING WATER
CONTAMINATED BY DISSOLVED VEGETABLE MATTER, to be as follows:-
Having, as the result of extensive research carried on during the past twelve-
mouths, arrived at the conclusion that such vegetable matter as is found dissolved
in many natural waters is held in solution in the form of various acid compounds
(which may be termed generally the 'humus-acids'); that such vegetable matter is
rapidly fixed by simple iron; and that the salts of iron thus formed being neutral
salts are rapidly decomposed by exposure to atmospheric oxygen, the iron being
completely precipitated, either as ferric bydrate or as basic salts of iron, which are
easily removed by mechanical filtration; I do propose to apply these ascertained
chemical principles (a) to rendering such waters wholesome and portable, (b) to the
purification of peat-waters on a large scale.

page_text: I, ALEXANDER IRVING, of Wellington College Wokingham, and Senior Science
Master in the said Wellington College, Clerk in Holy Orders, do hereby declare
the nature of my invention for THE PURIFICATION OF WATER CONTAMINATED BY
DISSOLVED VEGETABLE MATTER, and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement:-
Contamination of water by dissolved vegetable matter occurs as a result of
various causes, and is to be detected in natural waters;
(1.) In those from wells of small depth and surface springs; where the surrounding
country (old forest lands or otherwise) is covered more or less with forest-litter,
heaths, &c, or contains morasses or peat-bogs to any extent;
(2.) In those from deep wells which are supplied from deep-seated strata, in which
vegetable débris has been buried;
(3.) In waters collected from the surface of open moorlands by gravitation or
drawn from natural lake-basius.
It is found that such vegetable matter existing in the form of certain vegetable
acids (which may be conveniently spoken of under the general name of the
"humus acids") is decomposed very slowly by the action of Atmospheric Oxygen,
acting alone. These acids combine however very rapidly with simple metallic iron,
and, in the presence of an excess of that metal, form soluble neutral salts of iron.
On further exposure to the oxygen of the air, these salts are quickly broken up,
owing to the conversion of the iron into the peroxide, while the acids are resolved
for the most part into carbonic acid and water. The iron is precipitated either as
peroxide or as insoluble basic salts, and the water is thus rendered perfectly pure
and wholesome, so far as vegetable contamination is concerned.
In order to apply the chemical principles mentioned above, two processes are
required, as follows:-
Process No. 1. The Domestic Filter Process. This is intended to be available for
.ordinary household. use, and the following is a detailed description of it.
The Filter may be constructed either of Iron or. Earthenware, and is to be
capable of holding from 10 to 20 Gallons of water; so as to allow a sufficient period
of exposure of the water to the air for its complete Oxygenation; and for this
reason also the filter is to be kept open at the top. The Form of the filter is
circular in a transverse section.
In the accompanying diagram the apparatus is represented in vertical section.
The part numbered. (1). is a simple basket made of rather coarse wire-gauze or
netting, its use being to hold the coarse sifted iron-borings or any other form of
iron fragments (nails &c), and permit at the same time free access of water to the
metul. It may be suspended by three (or more) iron hooks to the rim of the filter,
and is to be below the surface of the water. This plan has been adopted (1) for
the sake of economy, by avoiding all unnecessary complication in the construction
of the solid parts of the filter; (2) to make the renewal of the iron and the cleaning
of the filter as easy as possible. One good supply of iron will last from two to
three months.
No 2. represents a layer of fine sand, by which the ferruginous precipitate formed
in the upper part of the filter by oxidation is retained, by simple mechanical
filtration. This of course will need renewal from time to time. No 2a. is a circular
perforated plate of earthenware to keep the sand in its place.
No 3. represents a bed of fine gravel.
No. 4. is a small perforated dome-shaped structure to support the pressure of the
filtering materials, and at the same time allow free passage of the water to the tube

page_text: which is attached to it for the passage of the water into the chamber beneath.
This piece of apparatus is fitted with a caoutchouc collar into a hole in the centre
of the partition, which forms the bottom of the upper part (A.) of the apparatus.
No 5 represents the chamber in which the water is first received; and the wall
of this chamber is to be perforated, so as to allow free access of the air for the
further oxygenation of the water as it drops from the filter above.
:
No 6. is a circular plate upon which the water drops so as to splash and thus get
as fully oxygenated as possible. This is supported by an upright stem terminating
below in a cone which fits upon the next portion of the apparatus (No. 7.) In the
chamber (No. 5) the last portion of the iron in solution is precipitated as peroxide,
and is filtered off by passing the water through a perforated hollow plug (No. 7)
adjusted by a caoutchouc collar, to a hole in the centre of the diaphragm, which
separates the chamber (No. 5) from the lowest chamber (No. 8).
Between the parts of the apparatus Nos. 6 and 7 is a layer of felt. or asbestos
cloth, which serves as the filtering material, as the water passes from chamber
No. 5 to chamber No. 8. From the chamber No. 8 the water is drawn off as it is
required by an earthenware tap of ordinary construction, fitted into a tubulus at
the bottom of the chamber. One small hole is made in the wall of this chamber
to prevent compression of confined air.
The part of the filter represented under the bracket (A.) is to be made to fit with
a circular flange into the top of the part included under the bracket (B.).
Process No 2. Process on a large Scale for the purification of water from
dissolved vegetable matter, for the supply of towns with pure soft water from open
moorlands or from lakes.
This process requires very little description in detail. It is sufficient to indicate
the general mode of application of the principle: details will vary with the circum-
stances of each locality, and can be readily supplied by any intelligent engineer.
The water, whether drawn by gravitation from open moorlands or from a natural
lake-basin, is to be led into one or more spacious shallow basins, in which refuse
iron is distributed in considerable quantity on banks of gravel or shingle; and
the water is made to circulate by partition walls or ramparts through as great a
distance as possible in the open basin (or basins). By this means, and by the
agitation of its surface by winds, the water is more completely oxygenated, and
the chemical changes effected by the combined action of iron and atmospheric
oxygen, upon which the purification of the water depends, are effected more rapidly
and completely. Exposure of the water in this way for two or three days will be
found sufficient. Any form of clean iron (any old iron which is free from paint,
Brunswick-black &c.) can be utilized for this purpose: the mere fact of its being
somewhat rusty will not render it unfit for the purpose. In its descent from the
hills the water, after leaving the principal oxidizing-basin, must be made to full at
intervals over weirs constructed across the canal through which it flows, and for
the purpose of securing as complete oxygenation of the water as possible, the
water must be made to fall from the weirs over rough rock-work or blocks of stone,
so as to divide the current, and expose it to the air as much as possible.
In any case where the water is brought from a distance of some miles the
application of this plan is a very simple matter: On the other hand, where the
water for the supply of a town is obtained from a near source, the difficulties of
its application will be somewhat greater, but not insurmountable to the resources
of engineering science.
In the former case filtration can probably be dispensed with entirely, the
precipitated peroxide of iron settling down by simple gravitation long before the
water reaches its destination, just as the glacier-streams are clarified by Alpine
lakes in the latter case, filtration through beds of clean sand will have to be
resorted to, after full exposure of the water in open tanks to the air in contact
with iron.

page_text: The Process No. 2. has been demonstrated on a small scale by experiments
performed by me upon the peaty water of the artificial Lakes at Wellington College
during the summer of this year.
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 application of the combined action of ordinary atmospheric oxygen and
simple metallic iron for the removal of dissolved vegetable matter substantially as
herein before described.
(2.) A filter for domestic use substantially as hereinbefore described.
(3.) The Method of purifying water on the large scale substantially as herein-
before described.