IMPROVEMENTS IN PURIFYING POLLUTED WATER
Year: 1866

page_text: PROVISIONAL SPECIFICATION left by Charles James Wahab at the
Office of the Commissioners of Patents, with his Petition, on the 21st
November 1866.
I, CHARLES JAMES WAHAB, of Valleyfield, North Britain, Civil Engineer,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
PURIFYING POLLUTED WATER," to be as follows:-
This Invention relates to a peculiar mode of applying various substances
suitable for the purpose to the purification of sewage and other dirty or
polluted water, and consists essentially in applying the substances employed
by grinding or reducing the same by any convenient or suitable mechanical
contrivance in a stream of the water to be purified.
This new method of purifying water is applicable to all kinds of dry or hard
substances, as, for example, aluminous cake or other such chemical purifying
substances, but it is specially intended for the better, more economical, and
more expeditious use of all kinds of carboniferous substances, some of which
are so largely used for purifying water. Among these substances are the
following: Wood charcoal in every form, shale ashes (or shale refuse),
common ashes (or cinders), coal, coke, shale, and indeed all substances that
are or may be used to purify water by the action of the carbon which they
contain.

page_text: This improved mode is also applicable when using lime in any form, also
common earth and clay in any form, not excepting burnt clay, as also all kinds
of ochre, chalk, and the finer descriptions of earths, and indeed all manner of
bard dry (ie., not liquid) substances, that are or might be used either to
simply purify water, or to improve its condition for any special object.
As already observed any description of grinding or reducing apparatus, may
be employed, provided only that it can be made to work under water and is
capable of crushing the substance to powder. It may consist of heavy rollers
(as in a "pug" mill), or rubbing surfaces (as in a flour mill), or a pounding
or disintegrating apparatus, or indeed any means whatever by which the
substance is reduced to powder in the water.
The following arrangement will be found to answer well in practice:―
Supposing there is a large quantity of water polluted even to discolouration
with impurities in solution, and largely charged with impurities in suspension,
and that the substances to be used for its purification are charcoal with shale
refuse, and a small quantity of lime; let these substances be mixed just as
they come to hand in such proportions as may be desired; let the water to
be purified be conveyed by a pipe to a shallow cistern, in the middle of
which is a circular iron plate on which one or more large iron (or stone)
rollers are made to revolve between this iron plate and the sides of the cistern.
The bottom of the cistern should be made of perforated metal (or stone)
'slabs, the holes in which should not let through the smallest peas; there
must also be attached to the frame of the rollers sweepers or scrapers so
arranged that they shall feed in all that does not pass through the bottom of
the cistern to the rollers; this is simply a "pug" mill working in a cistern
with a perforated bottom. The purifying substances being thrown (either by
hand or by machinery) on the bottom of the cistern are swept in before the
heavy rollers and ground by them to powder, which the constant flow of dirty
water immediately washes away and carries off through the perforated bottom
of the cistern, and in doing so is brought most intimately in contact with
the whole of the substance as it is by degrees ground to powder. In a
precisely similar way any crushing or disintegrating apparatus may be made
to bring out the whole purifying power of any such substances by one single
'operation. If a sufficient quantity of the purifying substances has been used
the whole of the soluble pollution in the water will have been purifyed out,
but the pollution in suspension will have greatly increased; this however
is of comparatively little consequence, as such pollution is easily dealt with in
settling ponds and filtering beds of sand or gravel of small area and permanent

page_text: qualities. It is suggested that this system of purification is well adapted to
those cases in which the polluted water contains a large quantity of impurity
in sollution, as, for example, the discharges from manufactories, but it is not
adapted, nor is it intended to be used except as a preliminary process for the
purification of water for domestic purposes.