Improvements in or connected with the Treatment of Sewage.
Year: 1899

page_text: Date of Application, 17th Oct., 1899-Accepted, 20th Jan., 1900
COMPLETE SPECIFICATION.
Improvements in or connected with the Treatment of Sewage.
I, THOMAS JOHN BARNARD, of Trafalgar House, Truro, in the County of Corn-
wall, Consulting Mining Engineer, do hereby declare the nature of this inven-
tion and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement:-
-
My invention relates to the treatment of sewage and has a twofold object,
firstly the separation of the solid from the liquid matter in such a manner that
the liquid may be treated and rendered inocuous from a sanitary point of view
and secondly the conversion of the solid matter together with the material used
for the purpose of the separation with the addition of coal tar or the like into
a fuel.
I separate the solid from the liquid matter by filtration through a series of
filter beds in which carbon in various forms is used as a filtering material. I
know that carbon has been used for filtration but in my invention I use the
various forms of carbon in a specified order and in the manner hereinafter
described. The first of the series of filter beds I line with coal slack or screen-
ings the particles of which may vary in size from that of hazel nuts to walnuts.
The second of this series of filter beds I line with fine coke or coke breeze and
the third with charcoal broken into pieces of the size of walnuts. The passage
of the sewage through the first of the series of filter beds arrests the coarser
particles of solid matter, the second of the series the finer solid matter and
slime and the third of the series arrests any very fine particles which may have
passed through the second and the charcoal also absorbs free gases.
The solid matter having now been separated from the liquid I proceed to
deal with the liquid by upward filtration through slaked lime in the manner
hereinafter described. I find this upward filtration advantageous as the lime is
apt to become clogged when the filtration is downward. The liquid now con-
tains lime in solution and suspension and for the purpose of removing the sus-
pended lime I treat it in a similar manner to that in which tin and copper ores
are treated in launders or leats in which the heavy particles are separated by
gravitation.
Finally if the effluent is to be run into streams or rivers or where its milky
colour might be objectionable I filter it through a second series of filter beds
similar to those above described and in the same order but I may in addition
add to this sceond series of filter beds, as the last of the séries, one with sand
as the filtering material.
The effluent has now been treated and may be carried by drains to any
desired point without fear of the polution of rivers or streams.
The undissolved lime precipitated in the launders may be collected and used
again for the treatment of the effluent.
The filtering materials in both series of filters before they become too clogged
with the solid sewage matter to be effective are removed from the filter beds
and are replaced by fresh material.
Coal tar is now added to the materials removed from the filter beds and
mixed either in pug mills or spread out upon hard floors and rolled as for

page_text: example by hand, horse or steam rollers until sufficiently mixed when, the
whole is either moulded into blocks of any suitable size and shape and dried
or is piled in masses to be broken into lumps, after drying, ready to be used
as fuel.
The amount of coal tar or the like added to the material removed from the
filter beds varies from 2 per cent. in fuel for open grate purposes to 10 per
cent. in fuel for steam producing purposes.
In order that my invention may be more readily understood I append diagram-
matic drawings illustrating my invention.
In these drawings similar numerals of reference indicate similar parts..
Figure I is a diagrammatic section of a series of filter beds connected with
one another and preferably in such a manner that flow from one to another is
attained by gravity.
Figure II is a diagrammatic view of an upward filtration tank constructed
in accordance with my invention and having connected with it a launder con-
sisting of overflow tanks.
Figure III is a diagrammatic section of the second series of filter beds.
In Figure I, 1,2,3, are filter beds in which 4, 5, 6, are respectively broken
7. 8. 9. are outlet drains
coal or screenings coke or coke breeze and charcoal.
connecting 1, 2, 3, and 3 with the upward lime filter shown in Figure 2.
In Figure II, 10 is an upward lime filter consisting of a tank divided by a
partition 11 into two portions 12 and 13. The partition 11 is carried from the
top to near the bottom of the tank 10 and the front 14 of the tank 10, is lower
than the top of the portion 12.
The front 14 of the tank 10 forms the back of a launder or series of
tanks 15, 16, 17, arranged in step like fashion so that overflow may take place
from one to another.
An overflow from the last (17) of the series of tanks is provided and connects
with the first of a series of filter beds illustrated diagrammatically at Figure 3
in which 18, 19, 20, 21, form a series of filter beds similar to those shown in
Figure 1 and with the filtering material arranged in the same order but with
an additional filter bed 21, containing sand as a filtering material, forming the
last of the series.
In treating sewage in accordance with my invention it is first caused to flow
into the filter bed 1 where the larger particles of solid matter are arrested and
held by the coal 4 whence the flow continues through the drain pipe 7 to the
filter bed 2 in which the finer particles of solid matter are arrested and held
by the coke 5 then through the drain pipe 8 on to the filter bed 3 where the
last fine particles are retained and the free gases are absorbed by the char-
coal G.
From 3 the effluent flows through 9 to the upward filter 10 where it first
enters the portion 12 of the tank and passes down below the partition 11 and
up through slaked lime with which the portion 14 of the tank is kept filled.
From hence it overflows into tank 15 and into 16, 17, leaving the undissolved
particles of lime which fall by gravity to the bottom of the tanks. This undis-
solved lime may be removed and again used in the upward filter.
From the last (17) of the series of tanks the effluent flows to the series of
filter beds illustrated in Figure III and passes through them. The undissolved
lime which may have escaped through the launder is here arrested by the filter-
ing material and the solid matter together with the carbon filtering material is
ready for mixing and forming into blocks of fuel as herein before described.
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. In the treatment of sewage the upward filtration through slaked lime sub
stantially as set forth.

page_text: 2. In a process. for treating sewage the specific combination of steps set forth.
3. As an article of manufacture a fuel prepared by the process herein before
Bet forth.