Improvements in the Purification or Treatment of Sewage by the Biological or Bacterial Method.
Year: 1899

page_text: Date of Application, 2nd Aug., 1899
Complete Specification Left, 1st May, 1900-Accepted, 23rd June, 1900
PROVISIONAL DI MUITIVATION.
Improvements in the Purification or Treatment of Sewage by the
Biological or Bacterial Method.
I, CHRISTOPHER JOSEPH WHITTAKER, of Willow House, Blackburn Road,
Accrington, in the County of Lancaster, Chemical Engineer, do hereby declare
the nature of this invention to be as follows;-
It is now well known that crude sewage is charged with many varieties of
micro organisms which have the power of decomposing or breaking down the
unstable complex compounds composing or contained in sewage into more stable
and simpler forms, and, at the same time, converting many of the solid matters
into liquid and gaseous products. Time and a suitable temperature are the
chief factors in the development of these facultative organisms in sufficient
numbers to be effective.
In most cases, under ordinary conditions, many weeks or even months, elapse
before the micro-organisms have multiplied in sufficient numbers to carry on
this decomposition or breaking down sufficiently rapidly to be useful for purifica-
tion purposes.
Moreover, when these micro organisms have effected the decomposition they
are capable of in the decomposing tanks, there still remains in the sewage a
considerable amount of what may be called mineralized carbonaceous matters
and also mineral matters carried along with the sewage.
These carbonaceous and mineral matters the micro-organisms have no power
to further reduce, and they are floated up to the surface of the liquid in the
tank, forming a thick scum, the accumulation of which necessitates the emptying
of the tanks from time to time for the removal of this non decomposable matter.
The emptying of a mature tank, that is, a tank in the most efficient stage of
the process, for cleaning out, entails in re-starting a repitition of all the difficul-
ties and loss of time necessary to obtain mature conditions; and many weeks,
or even months, may elapse before the same uniform results and the highest
efficiency of purification or decomposition can be obtained.
The object of this invention is to provide a method of operation whereby
uniform and highly efficient conditions may readily at all times be established
in the decomposing tanks, either in new tanks or in tanks that have undergone
cleaning.
For this purpose I make use of the sludge deposited in sewage purification
tanks worked biologically or by the bacterial method as a culture or medium
for the purpose of inoculating crude sewage or supplying thereto the necessary
micro-organisms thereby promoting and securing immediately, efficient biological
action after any of the tanks have been cleaned out, and also in starting new
tanks.
In accomplishing this I provide tanks in series, four being sufficient although
I do not confine myself to that number. The crude sewage is allowed to flow
slowly through the whole of these, that is through No. 1 into No. 2, then into
No. 3 and finally into No. 4. By this method of working the grosser particles

page_text: are deposited in tank No. 1, the finer particles being carried forward. The
particles in settling in No. 1 carry down with them the facultative micro-
organisms which commence the decomposition. After several weeks these have
multiplied immensely, the gases which are generated through their action float
up to the surface the decomposing matters, the finer particles of which containing
colonies of micro organisms are carried forward together with the finer particles
in the crude sewage and are deposited in tank No. 2 where the same action as
in tank No. 1 is set up the still finer particles being carried into No. 3 tank
and so on the same sequence being carried out in the tanks Nos. 2, 3, and 4 as
in No. 1.
When the amount of sludge accumulated in any of the tanks renders it neces-
sary for it or them to be cleaned out, a portion of the sludge which contains
large numbers of micro-organisms is retained and is mixed with the crude sewage
in re-starting the tanks or tanks, this fine black deposited sludge not only acts
as a most efficient precipitant but at the same time provides a sufficient number
of micro-organisms to establish immediately efficient biological or purifying
action without the necessity of awaiting the gradual development of the
organisms as has hitherto been the case.
This organism containing sludge may also be used as a culture when com-
mencing the purification of sewage in new tanks, thereby promoting immediately
efficient biological or purifying action.
W. B. JOHNSON,
Agent.
Improvements in the Purification or Treatment of Sewage by the
Biological or Bacterial Method.
I, CHRISTOPHER JOSEPII WHITTAKER, of Willow House, Blackburn Road,
Accrington, in the County of Lancaster, Chemical Engineer, do hereby declare
the nature of this invention and in what manner the same is to be performed, to
be particularly described and ascertained in and by the following statement,
reference being had to the accompanying drawings:-
It is now well known that crude sewage is charged with many varieties of
micro organisms or bacteria which have the power of decomposing or breaking
down the unstable complex compounds composing or contained in sewage into
more stable and simpler forms, and, at the same time converting many of the
solid matters into liquid and gaseous products. Time and a suitable tempera-
ture are the chief factors in the development of these facultative organisms in
sufficient numbers to be effective.
In most cases under ordinary conditions, many weeks or even months, elapse
before the micro-organisms have multiplied in sufficient numbers to carry on
this decomposition or breaking down rapidly enough to be useful for purification
purposes.
Moreover when these micro-organisms have effected the decomposition of all
the substances they are capable of decomposing in the decomposing tanks there
still remains a considerable amount of what may be called mineralized car-
bonaceous matters, being the mineral debris of the solids in the sewage, and
mineral matters carried along with the sewage such as sand and the washings
from the roads and streets.
These carbonaceous and mineral matters, the microorganisms have no power

page_text: to further reduce and they are floated up to the surface of the liquid in the
tank forming a thick scum the accumulation of which necessitates the emptying
of the tanks from time to time for the removal of this nondecomposable matter.
Heretofore the emptying of a mature tank, that is a tank in which the decom-
posing is at the stage of its fullest efficiency, for cleaning out has entailed in
restarting a repetition of all the difficulties and loss of time necessary to obtain
mature conditions, and many weeks or even months may elapse before the same
uniform results and the highest efficiency of purification or decomposition can be
obtained.
The object of this invention is to provide a method of operation whereby
uniform and highly efficient conditions may readily at all times be established
in the decomposing tanks, either in new tanks or in tanks that have undergone
cleaning.
For this purpose I make use of the sludge deposited in sewage purification
tanks worked biologically or by the bacterial method as a culture or medium
for the purpose of inoculating crude sewage or supplying thereto the necessary
microorganisms in sufficient numbers and in a high state of effectiveness thereby
promoting and securing immediately efficient biological action after any of the
tanks have been cleaned out and also in starting new tanks. By "sludge" I
include the sludge liquor and the scum deposited or formed in the tanks.
In accomplishing this I provide tanks in series such as are shown in the draw-
ing in which Fig. 1 is a plan of four tanks, four being sufficient although I do
not confine myself to that number. Fig. 2 is a longitudinal section at the
line A, A, and Fig. 3 is a cross section at the line B, B, on Fig. 1.
1, 2, 3, 4 are the tanks, a is the sewer conveying the crude sewage, al is a
channel surrounding the whole of the tanks. bare screen walls near the ends of
each tank so as to leave spaces c. d, e, f, g, h, i, j, k, l, m, are sluices in the
channel a¹. n, o, p, q, r, s, t, u, are sluices in the inner wall of the channel at
opening into the spaces c. vare openings in the screen walls to allow passage of
the sewage, the screen walls breaking up the current so as to allow of more
uniform settlement. w are outlets for the sludge into the chambers x. The
bottoms of the tanks slope downwards to assist the flow of sludge to the outlets.
y is the final outlet for the sewage. As arranged the sluices d, f, h, j, l, are
open and the sluices c, g, i, k, m, shut; all the sluices n, o, p, q, r, s, t, u are also
open. The crude sewage is allowed to flow slowly through the whole of the tanks
as follows; that is from the sewer a into the channel a past the sluices d and n
into the tank 1, from thence by the openings and sluices u, 1, and t, into tank 2,
from thence by the openings and sluices o, f and p into tank 3, and finally
by sluices s,, and r into tank 4, the sewage from 4 which cannot be further
decomposed flowing away by the sluices q, h, and outlet y for other treatment
as desired. The arrows show the direction of flow. By this method of working,
the grosser particles in the sewage are deposited in tank 1 the flow therethrough
being sufficiently slow to allow of settlement; the finer particles are carried for-
ward into tank 2. The particles in settling in tank 1 carry down with them the
facultative microorganisms which commence the decomposition. After a period
of several weeks these have multiplied immensely, the gases which are generated
through their action floating or carrying up the decomposing matters to the
surface of the liquid. The finer particles which contain colonies of micro-
organisms and which do not settle quickly in tank 1 are carried forward together
with the finer particles of the crude sewage through the openings and sluices
before described and are deposited in tank 2 where the same action as in tank 1
is set up the still finer particles being carried into tank 3 and so on, the same
sequence being carried out in the tanks 2, 3, and 4 as in tank 1.
When the amount of sludge or scum accumulated in any of the tanks renders
it necessary for it or them to be cleaned out, a portion of the sludge, liquor, or
scum, which contains large numbers of micro-organisms is retained and is mixed
in any convenient way with the incoming crude sewage when it is readmitted

page_text: for restarting the decomposition in the tank or tanks. This sludge liquor, or
scum provides a sufficient number of micro-organisms to establish immediately
efficient biological or purifying action without the necessity of awaiting the
gradual development of the organisms as has hitherto been the case of restarting
tanks.
This organism containing sludge, liquor, or seum may also be used as a culture
when commencing the purification of sewage in new tanks by being mixed in
sufficient quantity with the crude sewage in such tanks thereby commencing
decomposition and promoting immediately efficient biological or purifying action:
any sludge not utilized as above described may be burnt or otherwise disposed of
as desired.
When a tank say tank 1 is being cleaned out the supply of sewage to the
other tanks is carried past it by shutting the sluices d, n, and u, and opening
the sluice m. The other tanks may be separated from the series by operating
the corresponding sluices, as will be obvious.
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
First. The method of facilitating the commencement of biological or bacterial
decomposition or purification of sewage consisting of mixing with such sewage,
sludge, liquor, or scum containing micro-organismis obtained from sewage pre-
viously and similarly treated or purified, substantially as and for the purpose
set forth.
Second. The method. of obtaining from sewage, sludge, liquor or scum con-
taining large numbers of micro-organisms by passing the sewage through tanks
in series in the manner substantially as described.
Third. The process of purifying sewage consisting of passing the sewage
through tanks in series, collecting the sludge, liquor, or scum or part thereof
from a tank and mixing such sludge, liquor, or scum with the sewage next
admitted into a cleaned tank substantially as and for the purpose set forth.
Dated this Twenty-eighth day of April 1900.
W. B. JOHNSON,
4, Clayton Square, Liverpool, Agent.