Improvements in Filters for the Removal of Bacteria and Germs from Water and Sewage.
Year: 1893

page_text: Date of Application, 23rd Jan., 1893
Complete Specification Left, 23rd Oct., 1893-Accepted; 9th Dec., 1893
PROVISIONAL SPECIFICATION.
Improvements in Filters for the Removal of Bacteria and Germs
from Water and Sewage.
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:
I have noticed in connection with the filtration of waters and sewages, that much
of the purification, in so far as nitrification and the removal or destruction of
bacteria, are concerned, is brought about in the layer or stratum of deposit which
gradually accumulates upon, or in, the first few inches of the filter bed when the
same is in work. I therefore, in order to accelerate and perfect this process,
deposit or place upon or-in the filter bed, during the course of construction of the
same, or after its periodical cleaning or at other suitable time a sufficient quantity
of suitable material to retain or destroy, or both retain and destroy germs or bacteria.
I prefer to use such a material as shall also have an oxidizing effect and therefore
tend to propagate that form of bacterial life which produces nitrification.
Materials I find suitable to use are hydrated oxides of metals, such as iron,
manganese and aluminium, finely divided carbonised, or calcined carbonate of iron,
or finely divided peroxide of manganese; I do not limit myself to the use of these
materials but may employ any suitable substance or substances provided it or they
be in such a fine state of division that while allowing the liquid to percolate
therethrough, it will retain in or upon itself bacteria and other germs.
I may deposit or place the material to be used, on or in the filter bed in any
convenient manner, for instance by spreading it in a layer upon or in the filter bed,
by mixing it with water and running or sprinkling the resultant liquid upon the
filter bed, or I may mix it with sand or other material and place it upon or in the
filter bed; the thickness of material to be used depends upon its fineness, and may
vary from a quarter of an inch to two or three inches, or more.
Dated this Twenty-first day of January 1893.
COMPLETE SPECIFICATION.
Improvements in Filters for the Removal of Bacteria and Germs
from Water and Sewage.
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 ascer-
tained in and by the following statement :-
I have noticed in connection with the filtration of waters and sewages that much
of the purification, in so far as nitrification and the removal or destruction of
bacteria or germs in the said waters and sewages are concerned, is brought about in
the layer or stratum of deposit which gradually accumulates upon or in the first
few inches of the filterbed when the same is in work. This gradual accumulation
of matters deposited out of the waters or sewages during the filtration of the same.
is of necessity uncertain, sufficient matter may be deposited in two or three days or
it may take two or three weeks according to the condition of the water or sewage,
and all the water or sewage filtered before a sufficient quantity of matter has been
deposited by the said water or sewage upon or in the filter bed is from a
bacteriological point of view impure. My invention has for its object the
construction of a filter bed which for its bacteria or germ removing properties
1

page_text: shall not be dependent upon the deposition of impurities upon or in its surface
during the working of the said filter bed.
In carrying my invention into effect I deposit or place upon or in the filter bed,
during the course of construction of the same or after its periodical cleaning or at
other suitable time or times, a sufficient quantity of suitable material to retain or
destroy or both retain and destroy the germs and bacteria in the water to be filtered.
I use any material which when in a powdered or finely divided state will permit
of the passage of water therethrough while retaining in or upon itself bacteria or
germs, materials I find suitable are oxides, by preference hydrated oxides, of iron
manganese or aluminium, or carbonised or calcined carbonate of iron, or peroxide of
manganese, these or other materials I use in a very finely divided or powdered
condition and apply them to the filterbed in any convenient or suitable manner, for
instance I take a quantity of the finely divided or powdered material and mix it
with about its own bulk of fine sand, the sand being preferably wet so that the said
material shall stick round each granule of the sand and the mixing of the sand and
the said material be thus perfect, I place a layer or layers of the said mixture, of a
depth of about three inches I find suitable, on the top of or in the body of the filter
bed; or I place a layer or layers of the said finely divided or powdered material, a
layer of a depth of a half inch to one inch I find suitable, on the top of or in the
body of the filter bed; or I mix a sufficient quantity of the finely divided or
powdered material with water and run or sprinkle the resultant liquid or slurry on
the top of the filter bed, or in the body of the filter bed during the construction of
the same.
In preparing the said material for use in the filterbed, the method I adopt is to
reduce the same to a powdered condition by grinding and then to sift it through a
sieve having about sixty meshes to the lineal inch, the material that passes through
the said sieve I use for the beforementioned purposes.
I find that in addition to bacteriological purity I obtain in almost all cases
increased chemical purity, especially when I use a finely divided or powdered
material having in itself oxidizing powers, and such said material I prefer to use.
I prefer to remove the suspended matter from the waters or sewages by any
convenient means before running the same on to filter beds constructed as before
described.
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 improved methods of constructing filter beds substantially as described.
2. The admixture of a finely divided or powdered material with sand, preferably
wet sand, a layer or layers of the mixture being placed upon or in the filter bed,
substantially as and for the purpose described.
3. The employment of a layer or layers of finely divided or powdered material
upon or in the filter bed, substantially as and for the purpose described.
4. The method of covering or impregnating a filter bed with finely divided or
powdered material by mixing the same with water and running or sprinkling the
resultant liquid or slurry upon or in the filter bed, substantially as and for the
purpose described.
5. The employment of finely, divided or powdered peroxide of manganese or
carbonised or calcined carbonate of iron, either alone or mixed with sand, as
a layer or layers in or upon a filter bed, substantially as and for the purpose
described.
Dated this Twenty-first day of October 1893.
F. PULLEN CANDY.