AN IMPROVED MODE OF TREATING SEWAGE AND OTHER CONTAMINATED WATERS. SEWAGE AND OTHER CONTAMINATED WATERS.
Year: 1873

page_text: LETTERS PATENT to John Leigh, of Manchester, in the County of
Lancaster, for the Invention of "AN IMPROVED MODE OF TREATING
SEWAGE AND OTHER CONTAMINATED WATERS.
SEWAGE AND OTHER CONTAMINATED WATERS.'
"
PROVISIONAL SPECIFICATION left by the said John Leigh at the
Office of the Commissioners of Patents, with his Petition, on the
11th June 1873.
I, JOHN LEIGH, of Manchester, in the County of Lancaster, do hereby
declare the nature of the said Invention for "AN IMPROVED MODE OF
TREATING SEWAGE AND OTHER CONTAMINATED WATERS," to be as follows:-
I propose to purify sewage and other contaminated waters by adding
thereto in suitable vessels with agitation a solution of an earthy salt, and
afterwards a solution of silicate of soda or of potass, whereby a precipita-
tion or subsidence of the suspended matters in the sewage or other waters
is produced.
Of the earthy salts I prefer to use a solution of alum or of sulphate

page_text: Should the sewage or other water after being thus treated contain
any gelatinous or albuminous matters in solution, or afford evidence of
other organic matter in solution, I propose to add a small quantity of a
solution of tannin or of some solution containing tannin thereto.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Leigh in the Great Seal Patent Office on
the 11th December 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
LEIGH, of Manchester, in the County of Lancaster, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eleventh day of June, in the year of
our Lord One thousand eight hundred and seventy-three, in the thirty-
sixth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said John Leigh, Her special license that I,
the said John Leigh, my executors, administrators, and assigns, or such
others as I, the said John Leigh, my executors, administrators, and
assigns, should at any time agree with, and no others, from time to
time and at all times thereafter during the term therein expressed,
should and lawfully might make, use, exercise, and vend, within the
United Kingdom of Great Britain and Ireland, the Channel Islands,
and Isle of Man, an Invention for "AN IMPROVED MODE OF TREATING
SEWAGE AND OTHER CONTAMINATED WATERS," upon the condition (amongst
others) that I, the said John Leigh, my executors or administrators,
by an instrument in writing under my, or their, or one of their hands
and seals, should particularly describe and ascertain the nature of the
said Invention, and in what manner the same was to be performed, and
cause the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said Letters

page_text: thereby, or by other matters held in mechanical suspension by adding
thereto and agitating therewith in suitable tanks, vessels, or receptacles,
a solution of an earthy salt, followed by a solution of silicate of soda or
of potash, whereby a precipitation or subsidence of the suspended
matters in the sewage or other waters is produced.
matters in the sewage or other waters is produced.
Of the earthy salts I prefer to use a solution of alum or of sulphate
of alumina, of sulphate or of muriate of magnesia, or of muriate of
lime.
Should the sewage or other contaminated water after being thus
treated contain any gelatinous or albuminous matters in solution, or
afford evidence of other organic matter in solution, I add thereto a
small quantity of a solution of tannin, or of some solution containing
tannin.
As the sewage and other contaminated waters will vary from time to
time in consistence and degree of dilution, so also will the quantity of
earthy salts and of alkaline silicates that may be required to produce
complete precipitation of the suspended matters.
The sewage or other contaminated waters to be treated may be received
in suitable tanks, receptacles, or reservoirs, and thereto added a solution
of alum, whether potash alum, soda alum, or ammonia alum, in such
proportion that a quantity, equivalent to two grains, and increasing from
that to ten grains for each gallon of sewage shall be added, or a quantity
of solution of muriate of lime, equivalent to one grain, and increasing
from that to seven grains for each gallon of sewage, or of a solution of
sulphate of magnesia, which shall hold dissolved from one grain to eight
grains of the crystallised sulphate for each gallon of sewage. For the
alums may be substituted the sulphate of alumina, prepared com-
mercially on a large scale for use in dyeing, by treating pure clay with
strong sulphuric acid. When this is used a somewhat smaller quantity
will be required.
After any of these carthy salts have been added to the sewage or other
waters proposed to be treated, and well mixed therewith, a solution of
silicate of soda or of silicate of potash is to be added, by which an
insoluble carthy silicate will be formed, and this in its fall through the
liquid will carry with it to the bottom of the tank or vessel such matters
as may have been held in suspension in the liquid.

page_text: The proportion of silicate of soda or of silicate of potash to be added
to the sewage or other contaminated waters to which the carthy salts
have been already added will vary slightly in amount accordingly as a
less or greater amount of these salts may have been primarily contained
in the liquids to be treated. A quantity of solution of silicate of potash,
containing one hundred and seventy-one pounds of dry tetra-silicate of
potash, or of a solution of silicate of soda, containing one hundred and
eight pounds of dry mono-silicate of soda, may be added to a quantity of
sewage or other contaminated water, with which about four hundred
and seventy pounds of alum or fifty-five pounds of muriate of lime, or
one hundred and twenty-three pounds of sulphate of magnesia have been
mixed. Alkaline silicates are prepared on a large scale for commercial
purposes, and each manufacturer has certain proportions of silica and
of alkali, which he prefers in the manufacture of his silicates.
It is also possible that the proportion of silica to alkali may vary
occasionally with each manufacturer. As any of the soluble alkaline
silicates, commercially prepared, however, will suffice to precipitate the
bases of the earthy salts added to the sewage or other liquids to be treated,
I wish it to be understood that I do not confine myself to the use of
alkaline silicates containing only certain exact proportions of silica and
alkali, but I claim to use any soluble alkaline silicates, nor do I confine
myself to the quantities of earthy salts herein-before mentioned to be
added to the sewage or other foul waters, inasmuch as the sewage may
sometimes in consequence of the large quantity of water added to it by
rain and from other sources be so much diluted that smaller quantities
than those mentioned of the earthy salts may be sufficient.
Should the sewage or other contaminated waters, treated as herein-
before mentioned, appear to be slightly milky or turbid after the
subsidence of the precipitate formed, I add a small additional quantity
of the solution of alum or other carthy salt, and reagitate the mixture,
after which, on subsidence of the insoluble matter or precipitate the
water is usually clear.
Sewage often contains in solution a quantity of gelatinous or
albuminous matter, the putrefaction of which renders the smell of the
sewage very offensive. To prevent the continuance of this putrefaction
after the sewage has been cleared of its suspended matters, I add a small
quantity of a solution containing tannin.

page_text: Signed, sealed, and delivered
by the within-named John
Leigh, in the presence of
G. SEPTIMUS HUGHES,
Patent Agent,
Manchester.
JOHN LEIGH. (L.S.)