The Pacific commercial advertiser. [volume] (Honolulu, Hawaiian Islands) 1885-1921, 1908-12-31


which passes before this takes plac
may be less perfectly filtered, but ever
then, the filter may be so operated tina
nearly all of the bacteria will be de
posted in the sand and not allowed t.
pass through into the effluent.
As the sediment layer increases il
thickness with continued filtration, in
creased pressure is required to drive
the desired volume of water through its
pores, which are ever becoming smaller
and reduced in number. When the re-
quired quantity of water will no long,
er pass with the maximum pressure
allowed, it is necessary to remove, by
scraping. the sediment layer, which
should not be more than an inch deep.
| This layer contains most of the sedi-
ment and the remaining sand win act
almost as new sand would do. The
sand removed may be washed for use
again, and eventually replaced when
the sand becomes too thin by repeated
sc-apings. These operations require
that the filter shall be temporarily out
of use and as water must in general
be supplied without intermission, a
number of filters are built together SO
that any one of them can be shut out
without interfering with the action of
the others.
The relation of filters to the pumps
varies with local conditions. With
gravity supplies the filters are usually
located below the storage reservoir,
and, properly placed, involve only a
few feet loss of head
Superintendent Campbell endorses
only the slow filtration system It will |
take at least one acre in area to filter |
3 100000 gallons per day, so that to |
filter Nuuanu water, 100000 gallons, |
we would have to use at least 215 |
acres for filter beds. The plant must :
be duplicated so as to take care of
all this water. A filtration plant would
also require a clear water reservoir
to hold from 100000 to 5,000,O 900 gal
Ions and this would have to be covered I
on account of the rapid growth of
algae.
Bacteria in Water.
The ordinary water bacteria are of
The harmless and beneficent kinds,
which, depending upon dead organic
matter for sustenance, bring about its
into simple chemical sub
stances. How many species of these
organisms exist in water
cannot be said, but about two hundred
have thus far been described.
they may be present in small or enor-
nously large numbers without being
of hygienie significance, al
hough their existence in large num-
,ers indicates the presence of an abun-
lance of organic matter, and yet they
nay thrive and multiply enormously in +
water containing almost no organic
'ood materials. Indeed, multiplication
occurs more rapidly in pure than pol
uted water, but diminution in num-
,ers is also more rapid. In impure
water they multiply slowly, but their :
growth is persistent, and, under or'li-
lary natural conditions, sudden duni-
tuition in numbers does not occur. In
water bacteria are found in |
much greater abundance in surface WI
ers than in those derived from tie
oil. Indeed, many observers, includ
ng Koch and Fraenkel, have ma ntain.
d that waters from the unp0lluted
upplies are particularly sterile. This,
however, has been shown by Sedgwick
nd Prescott not to be the case.
The feces from a man contain on
n average perhaps 1,000,000,000 bac-
eria per gram, most of them being the
formal bacilli of the intestines, Ba-
illus coli cOmmunis. Assuming that a
nan discharges 200 grams or about
even ounces of feces daily, this would
i've 100000, 100000 bacteria discharg
d daily per person. The number of
actually found in American
ewage is usually higher, often double
his number per person, but there are
Their sources of bacteria in sewage,
nd in addition, grOwths or the reverse
nay take place in the sewers, accord :
ng TO circumstances. A considerable l
roportion of the water supplies of
he cities of the United States are so
diluted that in case cholera should
ain a foothold upon our shores, we
ave no ground for hoping for the
adorable experience of the English
tiles rather than the plague of Ham
urg in 1892. The broad fact that
tiles with polluted water supplies as
rule have high typhoid fever death ,
ates, and cities with good water sup
lies do not Except in the occasional
asses of milk epidemics, or when they
re overrun by cases contracted in
cities with bad water, as
the case with some of Chicago s
uburbs). is at once the best evidence
f the damage from bad water and
leasure of its extent.
Through the courtesy of Mr.. w. B.
tockman, Director of the Z. S.
department. of Agriculture, Weather
bureau, l am able to present the of
cial report of the rainfall as regards
he Nuuanu District.
Electric Light Station, from January
300, to August 1908:
Average by months-5.69, 1913, s.44,
sc, 4.73, 4.S1, 400, 5.49, 5.4S, Csc,
81, 6.7S. Annual, 1894.
Greatest, by months-1S.s9, 1856,
6.17. 1922, 9.47, 1O.47, 900, 900, 11.96,
3.91, 1876, 1912. Annual, 124.95.
Least. by months-O.63, lie, O.S7,
90. 1.O3. 1.79, O92, LII, 1.43, 2.91,
II, 2.66. Annual, 56.0S.
Luakaha, Lower:
Average. by months-9.22, 1859,
4.O6. 1913. 1915, 900. 9.S2, 1925,
O.aa. 11.37, 1862, 1918. Annual,
3S.06
Greatest. bv months-22OO, 1896,
I