Civil Engineering Reference
In-Depth Information
filtration
Fe: Unlimited
Mn: Unlimited
Usually use
pressure fil-
ters with
dual media
of anthra-
cite and sil-
ica sand
(9.8-12.2 m / h)
using pressure
filters
an ozone con-
tact tank with 3
to 5 min of
contact time
prior to the
filters
Rate of removal and
treatment perform-
ance are improved
with increasing
temperature and
decreasing TOC
content. Overdos-
ing with ozone can
drive the manga-
nese to permanga-
nate and result in
pink water com-
plaints and manga-
nese breakthrough.
Requires on-site
generation and
significant
power con-
sumption.
Ozone is a
primary
disinfectant.
Ozone generation
equipment is com-
plex and expensive
to buy, requires
significant electri-
cal power, has no
chemicals to han-
dle, and is easy to
control for a stable
groundwater
chemistry.
run times of
24 to 48 hr
and backwash
rates of 12-
16 gpm / ft
2
(29-39 m / h)
are typical
with back-
wash volumes
of2to5%of
the water pro-
duced
Relatively new
technology
for Fe and
Mn removal
but should
readily be
permitted by
state regula-
tory agencies
Chlorine,
KMnO
4
, and
filtration
Fe: Unlimited
Mn: Unlimited
Pressure or
gravity fil-
ters with ei-
ther:
1. Dual media
of anthra-
cite and
sand
2. Dual media
of anthra-
cite and
green-
sand or ox-
ide-coated
medium
With silica sand:
1. Gravity, 2-5
gpm / ft
2
(4.9-
12.2 m / h)
2. Pressure, 4-5
gpm / ft
2
(9.8-
12.2 m / h)
With greensand:
No additional time
required—
sufficient time
available in pip-
ing and the fil-
ter headspace
Rate of removal and
treatment perform-
ance are improved
with:
KMnO
4
is a
strong oxidant
that requires
care in han-
dling. KMnO
4
is an expensive
chemical. The
use of Cl
2
reduces the
KMnO
4
demand.
Requires the addition
and handling of
two chemicals.
KMnO
4
is corro-
sive and requires
special handling.
Simple and reliable
to dose and control
in typical ground-
water.
Anticipated filter
run times of
24 to 48 hr
and backwash
rates of 12-
16 gpm / ft
2
(29-39 m / h)
are typical
with back-
wash volumes
of2to5%of
the water
produced
''Classic'' North
American
method for
the removal
of Fe and
Mn. Readily
accepted by
the state
regulatory
agencies.
•
Increasing
temperature
•
Higher pH
•
Decreasing TOC
content
Overdosing with
KmnO
4
can lead to
pink water
complaints.
4 gpm / ft
2
(9.8
m / h) max.
