Richmond dispatch. [volume] (Richmond, Va.) 1884-1903, 1885-08-12

wsrH IRON As 4 PURIFIER.

Ls<xe scale.
In the July No. OF tho Scientific
Amsrisaa there appears an article upon
the Bischof method Of purifying water
Cor city purposes, rs applied by Nc.
w. Anderson, civil engineer TO Ant
werp. Belgium, and as reported BY
him 10 the Institution OF Civil En-
eineers. This paper is especially in
ssresting and worthy OF the attention
OF our city at this time, when mode
Of purifying and sltering the water Of
the James Is Felt 10 be necessity.
Mr.. Anderson says:
Ia January, 1888, in a paper on the
Antwerp wster-works read at the In
situation Of Civil Engineers, ! described
the application Of Professor Bischofs
method OF filtration, through mixture
Of spopgy iron and gravel, to the puri-
fcaticn Of the waters OF the river Nethe.
The eighteen months additional expert
ence gain has shown that, so far as the
purihcation Of the water is concerned,
Professor Bischof's process leaves little
20 be desired but the working OF the
system has been costly, and the area Of
land required, as well as the quantity Of
iron necessary, has, in the case OF the
Antwerp water at any rate, proved very
much beyond the inventors expecta-
tions. The increased demands Of the
town rendered it necessary to extend
the arrangements for purifying the
water, and it became my duty TO advise
the directors Of the company on the
best means Of doing this.
The extension Of Professor Bischof's
method would have involved so great
an outlay that after trying, unsuccess-
fully, many experiments on direct fill
tration through unmixed iron at high
rates Of flow, determined to adopt a
plan first suggested TO me some years
ago by eur chairman, Sir Frederick
Abel, OF agitating the water to be pu-
rified with iron instead of attempt
ing to filter it. The object, in
either case, was to expose the water
rs muck as possible to an extended
surface Of iron consequently any plan
by which the iron could be made to
Keep itself clean by rubbing against
itself continually would seem to be
more rational way Of attaining this OBJ
ject than Of trusting to partial filtra-
ton through a more or less spongy ma
terial. The obstacle to trying Sir
Frederick Abel's method at a much
earlier date was the belief entertained
by Professor Bischof that a con-
tact Of about forty-fve minutes was
necessary q insure complete purif-
cation, and any such time would be
fatal to mechanical means of performing
the work. The late Professor Way and
Mr.. 0gston. it is true, had shoyp that
with very finely -diyidef IRON the effect
was much -.R6ie rapid, but there was
sti.ra coubt about its permanence. In
The autumn of last year revolving cy-
Under, 4 feet inches in diameter and
5 feet 6 inches long, was adapted TO
try Sir Frederick Abel's system. 1t
was Htttu WIN lnltt anu OutiSt
pipes, and with shelves or lodges
for scooping up the iron, rails
ing it to the top Of the cylin-
der, and then letting it fall through the
water. At first l began to run water
through at twelve gallons per minute,
which gave contact Of about forty |
five minutes, but | found that at this
rate the water was very heavily charged
with iron. ! gradually increased the
quantity to thirty gallons per minute,
and then found that LEO grains Of iron
were dissolved per gallon, or about
twelve times more than experience at
Antwerp showed to be necessary.
The flow was increased to sixty gal |
Ions, and even then 90 grain per gallon
was dissolved. The experiment looked !
so hopeful that fitted much larger
pipes to the apparatus, and having
made some other dispositions con-
nected with maintaining q uniform dis
tribution Of iron in the cylinder and |
preventing it being washed away by the
comparatively rapid current that would |
be possible, l sent the "reyolver,"
as it came to be called, TO Antwerp,
where it was put to work at the end Of
last February, and has continued to
operate ever since. The head available
for forcing the water through the re
volver is, at Antwerp, limited to
feet, but by fitting very large pipes !
have managed to get l66 gallons per
minute through; this gives & contact
of about 80 minutes, and is so amply
sufficient that | feel sure that, even for
the waters OF the Nethe, much less
time will be adequate. The charge Of
iron is about 500 pounds, and the guam
tity taken up by the water, including
impurities and very fine iron washed
AWAY, during run of thirty-three days,
was 0'l76 grain per gallon.
BY making suitable arrangements,
and choosing favorable time with re-
spect to the demands Of the town, we
were able to obtain samples of water
that have been purified by the "reyol-
yer" only; and after proper exposure
to the air, followed by filtration through
one Of the large sand filters, the result
obtained has been that the color was
very little different from distilled water,
the free ammonia was reduced from
0.032 grain per gallon to 0'00l, and
the albuminoid ammonia from 0.0l3
grain to 0'0045. The "reyol-
yer - turns at the rate Of
about one-third revolution per minute,
sndrequires scarcely apprecisble power.
The area occupied by apparatus for
dealing with 100000 gallons per day
is 20 feet by "a feet, and it can be in
trodueed into any existing system of
filters, for by enlarging the inlet and
outlet pipes TO suitable diameter q
head Of some IL inches will suffice to
pass the water through. Ii can easily
be arranged so rs to be used or not,
IS the state Of the water 10 be
purified may warrant, and the consump-
ton OF iron, being only about twenty
pounds per million gallons, is quite al
insignificant expense. II riu b. fouaC
10 remore all eo,sr from water, whethel
caused by peat or clay, and riH .fdcili.
tate shs action Of sand filters 6y III
p<cUiiar curdliHg effect fhs iron La