Page 71 - Industrial Wastewater Treatment, Recycling and Reuse

is
aqueous
from
its
using
broad
carcinogenic
or
seasonal
aqueous
It
its
insoluble
has
the
acid
Cr(III).
the
a
in
Zn
sulfide
NF
also
a
considered
for
as
limitations
from
excessive
over
of
the
and
from
Recently,
sulfide
hydroxide
method
removal
Chemical
than
are
hand,
dissolve
temperature,
operate
be
Cr
remove
sulfides
to
toxic
hexavalent
calcium
an
been
other
used
poses
believed
pH.
for
because
metal
may
application.
can
more
alternative
to
also
because
of
widely
the
which
effluents.
using
agent
difficult
condition
range
into
pH,
has
10–100-fold
toxic
is
On
limitation
Cr(VI)
precipitation
a
UF
to
precipitation
precipitating
pH
fluctuations,
hydroxides.
wide
is
of
wide-scale
promising
sensitivity
more
industrial
Adsorption
and
of
removal
alkaline
phase.
a
range
own
over
RO
also
and
water
mg/L
fresh
0.1
Cr
for
hexavalent
mg/L
0.1–2
wastewater treatment—cont'd Methods Treatment Limits chemical of out arising sludge chemical may ions Zn of exchange ion or precipitation treatment, Biological fertilizer. as used be has high effective, cost as considered although Industrial Wastewater Treatment, Recycling, and Reuse: An Overview streams. F
discharge,
Cr
in Discharge Total
removal
metal
important of electroplating, industries
of Effluents dye,
Examples in Leather, photographic
1.4 Occurs
Table Metal Cr