Los Angeles herald. [volume] (Los Angeles [Calif.]) 1890-1893, 1891-10-12

20 per cent. of water, as some came
straight from the press. The sludge
gives ample heat for its own distillation,
and might also be used to raise steam
in the same furnace if desired.
The ammonia comes over with the
LIQUOR Just as in gas works, together
with a quantity of light, buttery tar,
which floats on the liquor. The cakes
are reduced to fine ash, which, if the
Temperature is raised by increasing the
blast. can be changed into clinker. A
very slight blast is sufficient to distill
with, merely enough to get the products
Of distillation through the condensers.
Now, the first question that will sug-
oest itself is, what portion of the theo-
retical ammonia is actually obtained?
Eighty per cent. was what l actually
obtained with the apparatus l had
there. and it is at least probable that
more could be obtained with better
apparatus.
uncondensed gases will burn, being of
similar composition to what is termed
eproduce gas" This might be en-
Moved in raising steam to drive the fan,
humps, etc., working up the ammonia
iiouor or distilling the tar. had
originally intended to mix the ammonia,
fixed as sulphate with the ash, to form
a manure for general purposes. This
cannot be done if there is much free
lime in the ash, as ammonia is olsen
gagged too rapidly.
Here, perhaps, ought to state the
reasons which compelled me to give up
working at LeytOn, where | was treated
with great kindness by the authorities.
! The first reason was the low value of
the ash, which contained about 90 per
cent of calcium salts. This great excess
is due to the addition of lime first to
precipitate and afterwards to press with.
The lime also introduces another diff
Guilty. and that is the production of
clinker in the furnace. The tempera-
ture OF the furnace must of course be
kent ND to that point at which infiam-
! mable gas is produced, and when this
is done it is hard to avoid a certain
amount OF clinker being formed also.
In the case OF some towns where
clinker can be used this might be done,
and the ammonia alone relied on as a
source of income, since sludge cake, even
as produced at present, will yield enough
ammonia to more than pay for its dis
tillation in the manner described.
The uncondensed gases from distilling
or baking sludge cake, have an exceed
ingly unpleasant smell, and must be
burned to avoid creating nuisance.
Some time ago experiments were made
of burning coke made from London sew
age in kind OF oven, built with parti
tions so that the heat from one assists
the one next to it, fires being lighted
successively. The cake burned without
difficulty, but the ash being of little
value it was abandoned. / believe no
attempt was made to collect the am
monia.
A few years ago some ovens were tried
at Leyton for burning the sludge cake
to obtain ash; they either did not at
tempt or were unable to obtain the am
monia.
There was little or no sale for the ash,
and it was subsequently abandoned.
3. As regards method of precipita-
ton to 60 with the method of utilizing
sludge cake which have just detailed;
1t is obvious, where separate system
| is used for storm water the ash will be
worth more, as it will not be so contain
mated with silica and other mineral
substaneds from the roads.
OF course, what is wanted is a means
of producing a sludge cake as rich as
/ DOSElDlG III dilU pllOSpndOO az
! the same time, without adding precipi-
tants in any large quantity, which
would lower the percentage of phosphate
IN the ash. At the same time the press
ing ought to be done without lime; this
is possible, as it is done at Kingston.
| have not been able to make expert
ments on this subject, but it seems GER
tain that the use of lime ought to be
avoided at all costs, and | should be in
clined to try carbonized sludge in powder
mixed with salts of alumina and iron,
after precipitation running the liquid
through bed of Jumps of carbonized
sludge; when this bed is too foul to use
any longer it can be burnt in the fur
mace.
was not successful in preparing car
bombed sludge in the same furnace that
1 have spoken OF, though [ think it
could be done in larger one. The at
tempt was made to rake out portion of
the sludge after being carbonized but be-
fore it was burnt to ash. At any rate,
if this cannot be done the cost of carbon
izing sludge in closed retorts heated by
the inflammable gases | mentioned,
would not be prohibitive.
1t seems probable that by using suf-
ficient quantity of this carbonaceous
matter (Which can so readily be re-
newed) a considerable degree of purity
could be arrived at in the effluent.
Any seeds present in the sludge, which
are sometimes very numerous, are of
course destroyed in the furnace and any
vegetable matter reduced to ash, so that
potash contained in the solids suspend
ed in the sewage is rendered available.
As to what proportion the resulting
manure, if the whole of my scheme
were in operation, would be by weight
to the cake dealt with, it is not possible
to speak with accuracy it might prob
ably be one-tenth.
At the present day it is fast becoming
widely felt that it is the duty of towns
to treat their sewage in some way, so
that no injury may becaused to health,
yet we surely ought not to rest content
with processes which yield nothing but
refuse. 1t is now many years since Lie
big insisted on the need of maintaining
proper circulation of phosphates and
ammonia if we wish our land to remain
fertile, and this need instead of dimin-
ishing shows itself more clearly every
day.