IMPROVEMENTS IN THE MEANS OF PURIFYING SEWAGE AND OTHER FOUL WATERS
Year: 1876

page_text: PROVISIONAL SPECIFICATION left by Charles Denton Abel at the Office of
the Commissioners of Patents on the 21st November 1876. A communication
from abroad by Felix Langlet, of Reims, Marne, in the Republic of France.
CHARLES DENTON ABEL, of Southampton Buildings, in the County of Middlesex.
"IMPROVEMENTS IN
THE MEANS OF PURIFYING SEWAGE AND OTHER FOUL
WATERS."
According to this Invention sewage and other foul waters are purified by settle-
ment of their impurities, by simple filtration, by filtration through charcoal, by
intermittent filtration producing innocuous products, by treatment with chemicals,
or by a combination of these processes, suitable channels, tanks, and other appliances
being arranged for this purpose in the following manner :- -Ground is selected
whence there is little fall to a river or other natural drain, and if necessary the
sewage is pumped up to this level. It flows first into a tank of considerably larger
sectional area than the supply channel, in which a portion of the solid impurities
are deposited by settlement. From this first tank it flows to a second and third
tank of like kind, the passage from each tank to the next being provided with a
weir of the following construction :-It consists of an upright at each side of the
passage, with a vertical groove, into which are lowered a number of horizontal bars
of heavy wood, such as oak. These bars, crossing the channel from side to side,
form a dam with interstices between the bars, through which a portion of the liquid
passes, the larger and heavier solid impurities being kept back by the dam. The
bars do not extend up to the surface of the liquid, and consequently a considerable
flow takes place over them, and to keep back the floating impurities a bar of light
wood, such as deal, extends across from side to side of the channel, being held at
each end in the vertical grooves, but being free to rise or descend according to
variations in the level of the liquid on which it floats. From the last of the settling
tanks the liquid flows into a filtering tank containing a filter arranged as follows:--
Several drain pipes extend side by side along the bottom of the tank, and commu-
nicate with the river or other discharge drain. On each side of these pipes there is
a wicker fence to retain a mass of gravel, or it may be sand, gravel, and fragments
of stone laid over the drain pipes, but straw or coarse marsh hay is preferred to
these materials, because after serving for filtration it can be utilized as manure.
The liquid in the tank finds its way through the fence and filtering material to
the pipes, by which it is discharged in a purified condition.
In cases where it is desirable to use charcoal a bed of that material is first laid on

page_text: A second fence may
be placed on each side of the filter; the space between it and the inner fence being
filled with the straw or coarse hay, which may from time to time be removed as it
becomes foul without so frequent replacement of the inner filtering materials.
the drain pipes, and over that is placed the filtering material.
Instead of a filter of the kind described, in which the flow is lateral, a filter in
which the flow is upwards may be arranged in the following manner :-The filtering
tank is deepened in the middle so as to form a sunken channel, over which is fixed
a framework supporting layers of filtering materials, having above them a channel
communicating with the discharge. The liquid in this case rises from the lower
channel to the upper, passing through the filter, and becoming purified on its way.
Such a vertical filter may be used in lieu of or in combination with the lateral filter
above described.
In any of the settlement tanks chemical substances may be introduced for the
purpose of effecting or accelerating precipitation. As sewage water in passing through
chalk or peat has its ammoniacal ingredients converted into innocuous nitrates the
liquid after depositing its solid impurities may be intermittently passed from the
settling tanks through a bed of chalk, peat, or a mixture of these substances instead
of the filter.
The tanks, channels, filters, and other appliances described above are provided at
least in duplicate, so that one set can continue in operation while the other set is
being cleansed. It is preferable however to provide more than two sets, so as to
give time for the matter deposited in the settling tanks to become sufficiently dried
for removal in the form of a partially solidified mud. Suitable sluices are provided
to divert the liquid as desired into the several sets of tanks.