Drinking
Water
Microbiology
Water
is
indispensable
for
life.
The
basic
human
physiological
requirement
for
water
is
about
2.5
litres
per
day.
This
drinking
water
should
be
free
from
chemical
as
well
as
microbial
contaminants,
since
the
potential
of
contaminated
water
to
transmit
diseases
is
very
high.
For
instance,
a
person
with
cholera
excretes
about
1013
bacteria
each
day.
The
infectious
dose
for
cholera
pathogen
is
106
cells.
Thus,
on
average,
an
infected
person
can
transmit
the
disease
to
about
ten
million
people.
Drinking
water
is
obtained
from
different
sources
like
well,
river
and
surface
waters.
Various
impurities,
from
branches
of
trees
to
invisible
microorganisms,
may
occur
in
these
waters
and
have
to
be
removed
before
the
water
is
supplied
to
the
public.
To
render
the
water
safe
for
drinking
it
has
to
be
treated
property.
Although
there
occur
some
similarities
between
sewage
treatment
and
drinking
water
treatment,
they
are
entirely
different
from
each
other.
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