Arizona republican., 1901-07-07
!OOD". MICROBES
"a AND GOOD WATER
ssng Experiments at Lawrence, Mass, Show the Utility
Of Bacteria in the Fabrication Of Contaminated
River Water Filtration Beds Consd-
cred as Living Organisms

, microbes of sewage are unable to do
such effective work in running water
as in still water, and that great basins
like that at Clinton, where the state
of Massachusetts is undertaking the
greatest reservoir in the world. make
the publication of the river water they
receive far more easy. besides being
more effective In bleaching from 1t all
stains of leaves and other substances
with which ii may have been discolored.
In theory of filtration. also. a better
knowledge of bacteriology IS responsible
for another direct change of position.
At the Lawrence experiment station the
river water--the dilute sewage" of
the bacteriolOgist- lis regularly purified
by being filtered through five feet of
sand. Naturally IL was at first sup
posed that the filters were d source of
danger unless they were fresh and
clean or had been recently sterilized.
Today, however the reverse is known
TO be the fact. 1t IS calculated that the
filters at Lawrence will remove from
water more than 80 per cent of the
organic matter ana 80 per cent of the
bacteria; but they win only do this
after the sand has become seeded"
with resilient microbes. forming a cur
tain,' sometimes called micro mem
brane, over the whole surface of the
hlter. II is not really a continuous cur
tain; each grain of sand has its own
settlement, so called, of bacteria, which
cover IL with a jelly-like mantle that
catches and imprisons the bacteria
contained in the water to be filtered.
These latter though too small TO be
seen without a microscope, are of ap-
prectable size-as Professor Sedgwick
explains 1t; Comparing molecules to
marbles. bacteria would perhaps. be as
large as telegraph pOles"-and many
OF them are covered, to their disad-
vantage. with hairy extensions. In the
tCrtuous course ot the water through
the filter, therefore, they are easily
caught on the sand mantles where they
must stag until they die of starvation
or old age.
The whole filter IL considered by the
bacteriologist as a living organism,
which must have a chance, for example,
to take in sufficient supply of oxygen,
VI WHICH may be hltitu ny steTIllZdtlOD
by heat The population of a filter, as
estimated by Professor Sedgwick. is,
for the first quarter of an inch down,
10000 600 microbes for each gram of
sand lat a depth OF an inch, 800 600
gram; and at depth of one foot, 100-
0c0 a gram. although these, figures will
vary according to the age of the filter
and the kind of sand used and the way
II is beoded. Incidental to taking such
n census of a filtration bed it has been
observed that grain of garden earth
may contain 100000 microbes-a fact
which may enable the curious to calcu-
late tine nourishment, If they choose,
of the common earth worm.
From experiment. at Lawrence OF the
Institute of Technology. II has been
amply demonstrated that any river
water purified by means Of a five foot
filter is safe and wholesome. and. fur
Their. that effluent water from proper
filtration of sewage would not be dan
gerous for domestic use. The records
have also shown that since Lawrence,
encouraged by the example OF the state
experiment station. has installed mu-
nicipal filter, though 1t is still using the
water of the Merrimac river. always
more or less contaminated by the drain