United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S2-83-085 Jan. 1984
SER& Project Summary
Polishing Industrial Waste
Stream Effluents Using Fly
Ash-Natural Clay Sorbent
Combination
Paul C. Chan, John W. Liskowitz, Mung-Shium Sheih, and Richard Trattner
Described herein is a laboratory
evaluation of the use of new, fly ash-
natural clay sorbent combinations and,
of the use of activated alumina for the
polishing of industrial effluent containing
fluorides and heavy metals. The work
was conducted at the New Jersey
Institute of Technology in Newark, New
Jersey.
The new sorbent materials studied
were acidic and basic fly ashes and
natural clays such as bentonite, bauxite,
illite, kaolinite, zeolite, and vermiculite.
Industrial waste effluents (3.8 x 106
liters per day) generated by the feldspar
mining and processing industry contained
significant concentrations of fluoride,
iron, lead, chromium, and cadmium.
In the laboratory evaluation, activated
alumina treatment was included for
comparison with the effectiveness and
cost of treatment using the new sorbent
combinations.
The most effective new sorbent
combination for the feldspar waste
stream was a mixture of illite, basic fly
ash, and lime. Lime was used to
maintain a pH of 6.3.
Fluoride and iron in the wastewater
were reduced from concentrations of
17.5 mg/l and 4.5 mg/l to 1 mg/land
0.020 mg/l, respectively. Lead, chromi-
um, and cadmium concentrations were
reduced from 0.12 mg/l, 0.05 mg/l,
and 0.15 mg/l to 0.013 mg/l, 0.015
mg/l, and 0.010 mg/l, respectively.
While the treatment process was
designed for maximum removal of
fluoride, it also provided effective
removal of the heavy metals. Maximum
removal of fluoride was achieved at a
pH of 6.3 with a minimum contact time
of six hours between the sorbent and
waste stream.
Regeneration of the spent sorbent
can be accomplished with 1% H2SO4- A
20% loss in sorbent capacity was
observed after the first regeneration.
Subsequent regenerations resulted in
no further loss of sorbent capacity.
Estimated materials costs for the
illite/basic fly ash/lime sorbent combi-
nations with spent sorbent regeneration
are 13.3 cents per 3.8 x 103 liters (1000
gallons) of wastewater. The use of
activated alumina with regeneration
costs twice as much.
Estimated materials costs for the
illite/basic fly ash/lime sorbent combi-
nation used once (without regeneration)
are 45 cents per 3.8 x 103 liters (1000
gallons) of wastewater.
Activated alumina without regeneration
costs $4.95 per 3.8 x 103 liters (1000
gallons) of wastewater.
Disposal of the spent illite/basic fly
ash/lime sorbent combination, when
no regeneration is done, should pose no
problem. Repeated washing showed no
significant loss of sorbed cations and
anions.
This report was submitted in fulfillment
of Grant No. R-805666 by the New
Jersey Institute of Technology under
the sponsorship of the U.S. Environmen-
tal Protection Agency. This report
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covers the period October 1, 1977 to
October 31, 1978, and work was com-
pleted as of December 31, 1978.
This Project Summary was developed
by EPA's Industrial Environmental
Research Laboratory. Cincinnati. OH,
to announce key findings of the research
project that is fully documented in
'Separate report of the same title (see
Project Report ordering information at
back).
Introduction
The objective of this laboratory investiga-
tion was to establish the feasibility, both
technically and economically of using
inexpensive combinations of fly ash and
clays as new sorbents for a polishing
treatment of industrial wastewaters.
The new sorbents have been found
effective for removal of heavy metals,
toxic anions, and organics from leachate
that is generated from industrial sludges
deposited in landfills (EPA-600/2-80-
052, June 1980).
The present study explores the use of
fly ash/clay sorbent combinations for a
polishing treatment of an industrial
effluent for the removal of fluorides and
heavy metals.
The wastewater used for this investiga-
tion came from a feldspar mining and
processing operation generating waste-
water at a rate of 3.8 x 106 liters per day.
The study was undertaken to investigate
the removal of fluorides, heavy metals,
and organics that may be present in
significant concentrations in this waste
stream.
Materials and Methods
Materials
The sorbent materials selected for this
investigation were fly ashes, zeolite,
vermiculite, illite, kaolinite, bauxite,
bentonite, and activated alumina, the
latter for comparison purposes. The
selection of these materials was based on
economic considerations, availability,
and potential for pollutant removal.
Origin and preparation of sorbent materials
is described in the final report.
The wastewater used in this study
resulted from mining and processing of
feldspar ore. The wastewater was collected
in five 5-gallon, lined drums and transported
to the laboratory. Three shipments of the
wastewater, three drums each time,
were made during the one-year study.
The results of the analysis of three
separate shipments of wastewater are
listed in Table 1.
Table 1. Analysis of Feldspar Wastewater
Concentration mg/l
Contaminants
F
Cel
CN
SO,
Ca
Cd
Cr
Cu
Fe
Mg
Ni
Pb
Zn
COD
pH
Sample 1
4.0
27
0.0
64
5.2
0.009
0.007
0.035
1.8
1.7
0.054
0.019
0.054
14
5.5
Sample 2
17.5
32
0.009
82
6.7
0.007
0.008
0.047
4.5
3.7
0.044
0.013
0.076
20
4.9
Sample 3
5.8
39
0.008
57
11.3
0.015
0.05
0.02
0.3
1.9
0.15
0.12
0.18
18
6.3
Methods
The investigation was performed in
three different phases: (1) static studies,
(2) dynamic studies, and (3) spent sorbent
regeneration.
1. Static studies: The static studies
evaluated the effectiveness of sorbents
for removal of major contaminants from
feldspar wastewater, the effect of pH on
sorbent capacity, the relation between
sorbent capacity and the desired effluent
concentration, and the length of contact
time between sorbent and wastewater.
Sorbent materials were contacted with
wastewater in an Erlenmeyer flask.
2. Dynamic studies: Lysimeter studies
provided dynamic conditions to evaluate
the removal capacity of the most effective
sorbent mixture, illite/basic fly ash/lime,
(determined as a result of static studies),
for fluorides and iron present in the
feldspar wastewater. Two different
hydraulic systems were studied; gravitation-
al flowandexpanded-bedflow. Lysimeters
were constructed of Plexiglass* tubing,
supported in a vertical position.
In the gravitational flow operation,
wastewater was fed to the top of the
column. A constant hydraulic head was
maintained in the lysimeters at all times,
and the volume of wastewater through
the packed sorbent material was continu-
ously monitored.
In the upflow expanded-bed operation,
the wastewater was fed through the
bottom of the bed at a velocity sufficient to
expand the bed without loss of the
sorbent in the overflow.
3. Sorbent regeneration: The spent
regeneration studies were carried out
Mention of tradenames or commercial products
does not constitute endorsement or recommendation
for use by the U.S. Environmental Protection Agency.
under batch conditions. A 1% solution of
sulfuric acid was used as the reagent.
Results and Discussion
Results of Static Studies
The sorbent materials were examined
for their effectiveness to remove fluoride
and iron from wastewater because these
two contaminants were present at
highest concentrations in the feldspar
wastewater (see Table 1). Both illite and
kaolinite showed comparable removals in
reducing the fluoride concentrations to
below 1.5 mg/l (Figure 1).
Basic fly ash was found most effective
in reducing iron from 1.8 mg/l to 0.02
mg/l (Figure 2).
The illite sorbent capacity for removal
of fluoride shows dependence upon pH,
with optimum pH for fluoride removal at
pH of 6.3. The Kaolinite sorbent capacity
for fluoride removal shows no dependence
on pH (Figure 3).
The sorbent capacity of a sorbent and
for a given pollutant decreases as the
initial concentration of the pollutant
decreases in the waste stream. Under-
standing the relationship between sor-
bent capacity and desired effluent con-
centration is important in estimating
the amount of sorbent required to achieve
the desired effluent concentration.
A minimum contact time of six hours
between the sorbents and feldspar
wastewater is required to insure maxi-
mum removals of fluoride.
Results of Lysimeters Studies
Based on the results of static studies, a
mixture of 50% illite and 50% basic fly ash
was selected for lysimeter studies to
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i
§
i
Wastewater Concentration = 4.0 mg/l
Bentonite
A Bauxite
Fly Ash (Acidic)
Fly Ash (Basic)
O //lite
A Kaolinite
» Zeolite
O Vermiculite
I
\
20 4O 60 80
Sorbent Concentration in Wastewater, g/l
100
Figure 1. Fluoride treatment (batch conditions).
determine that mixture's effectiveness in
reducing both fluoride and iron to
acceptable levels under dynamic (flowing)
conditions.
Gravitational Flows
Experiments performed under gravita-
tional flow operation showed that the
sorbent particle size range influencedthe
reduction of fluoride (best removals at
small particle size ranges) but did not
effect the removal of iron (Figure 4).
Increases in sorbent particle size
ranges allow larger flows, but at the same
time it significantly decreases the
effectiveness of the sorbent bed for
removal of fluoride.
Experiments with gravitational flow
showed that very large flows cannot be
handled by sorbent beds under gravitation-
al feed. Thus, passing of the feldspar
wastewater in the amount of 3.8 x 106
liters per day would be impractical.
On the other hand, experiments with the
upflow expanded-bed treatment showed
that large volumes of wastewater can be
easily treated in this way, and adequate
contact time for the sorbent to interact
with the wastewater can be maintained.
Operation of the upflow expanded-bed in
the illite/basic fly ash/lime sorbent
mixture in the lysimeters resulted in
reduction of fluoride levels from 5.8 mg/l
to 1.5 mg/l in the feldspar wastewater
(Figure 5).
Another practical way of contacting
sorbents with industrial wastewaters is
by adding the illite/basic fly ash/lime
mixture directly to the waste stream. The
sorbents added to the waste can be
removed in sedimentation basins, provided
that adequate settling rates are encoun-
tered. Settling tests carried out on the
illite/basic fly ash/lime mixture showed
that this particular mixture has compatible
settling rates.
The use of the new sorbent mixture
without regeneration of the spent sorbent
is economically and technically feasible.
Conclusions
1. On the basis of laboratory tests, the
illite/basic fly ash/lime sorbent com-
bination appears to be effective for
treating waste streams generated by
the feldspar mining and processing
industry. The sorbent combination can
be added directly to the waste stream
and the spent sorbent removed by
sedimentation at a loading rate of 1.77
x 104 l/mVday (432 gal/ftVday).
Also, the waste stream can be treated
in a sorbent bed operated in an upflow
expanded-bed mode. A six-foot-deep
sorbent bed can treat the above flows
at a loading rate of 7400 l/m2 (180
gal/ft2). This sorbent combination
reduced the iron, lead, chromium,
cadmium, and fluoride concentration
to levels that are generally acceptable
for potable water supplies.
2. Reliance upon gravitational flow
through the sorbent bed is impractical
for treatment of a feldspar waste
stream. The permeability of sorbents
limits the treatment to loadings as low
as 575 l/m2/day/ (14 gal/ftVday). A
sorbent bed with surface area of 6.7 x
103 M2 (7.2 x 104ft2) would be required
to avoid ponding at a 3.8 x 106 I/day /
(1MGD) flow rate.
3. Increasing the gravitational flow
through a sorbent bed by increasing
the particle size in the bed is not practi-
cal for treating large volumes of
wastewater. An increase in the parti-
cle size results in a decrease in the vol-
ume of wastewater that can be treated
with a given weight of sorbents. Ap-
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0.7
0.6
>
c
I
s
p
§
0.5
0.3
u
3
1 0.2
0.7
Influent concentration =1.8 mg/l
% Fly Ash (Acidic)
Fly Ash (Basic)
A Kaolinite
D ////te
I
I
I
_L
_L
_L
Figure 2.
20 40 60 SO
Sorbent Concentration in Wastewater, g/l
Iron treatment (batch conditions).
100
The difference is primarily associated
with the use of NaOH in the regenera-
tion of activated alumina.
6. It appears that the spent sorbent com-
bination may be disposed of easily. The
sorbent contaminants do not seem to
pose any threat to ground or surface
waters. Repeated washing of different
amounts of sorbents did not indicate
any fluoride concentration above 1.1
mg/l in the rinse water. This elimi-
nates the problem associated with the
disposal of a metal hydroxide as CaF2
sludge from the regeneration process.
However, replenishing the spent sor-
bents with unused sorbents raises the
treatment costs to 45 cents per 3.8 x
103 liters. Disposal of spent activated
alumina without regeneration would
amount to $4.95 per 3.8 x 103 liters.
Recommendations
The results of this investigation show
that, on a laboratory scale, the use of
clay/fly ash sorbent combination for
polishing the fluoride, iron, lead, chromi-
um, and cadmium in waste stream flows
from the feldspar mining and processing
operation is both technically and econom-
ically feasible.
An industrial-scale project should be
undertaken with the cooperation of
Federal agencies to demonstrate the use
of the fly ash/clay sorbent combination
for polishing the heavy metal-# and
fluoride-bearing waste streams on an
industrial scale.
The development of inexpensive treat-
ment technology would benefit industries
that have treatment facilities but require
additional polishing of their effluents for
removal of heavy metals and fluoride to
meet state and federal guidelines.
parently, the advantage of the in-
creased pore volume of the bed by in-
creasing the particle size is offset by a
reduction in the sorbent capacity due
to the decrease i n particle surface area
encountered with the larger particles.
4. The conditions required for maximum
removal of the fluoride also provide ef-
fective treatment of iron, lead, chromi-
um, and cadmium present in the feld-
spar waste stream. The maximum sor-
bent capacity for the removal of fluo-
ride occurs at a pH of 6.3, with a con-
tact time of six hours between the sor-
bents and wastewater.
The material costs associated with the
use of the illite/basicfly ash/lime sor-
bent for treating 3.8 x 103 I (1000 gal-
lons) of feldspar waste stream with re-
generation is estimated on the basis of
laboratory scale testing to be one third
that associated with the use of acti-
vated alumina. These costs amount to
13 cents per 3.8 x 103 and 45 cents per
3.8 x 1031 for the sorbent combination
and activated alumina, respectively.
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0.5
0.4
1
I
°'3
0.2
0.1
D Illite
A Kaolinite
5
pH
Figure 3. pH effect on sorbent capacity for fluoride (batch conditions).
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20
I
12
U
§
§ 4
1.0
Influent Concentration =17.4 mg/l
Particle Size > 0.042 cm
O Particle Size > 0.042 cm
A 0.021 cm < Particle Size < 0.042 cm
A 0.021 cm < Particle Size < 0.042 cm
O Particle Size < 0.021 cm
Particle Size < 0.021 cm
6 8 10
Volume Treated, Liters
12
14
16
Figure 4. Fluoride removal dependence on sorbent particle size (gravitational flow).
I,
L
i
2
§
o
Influent Concentration = 5.8 mg/l
Figure 5.
20
40
60 80 100
Volume Treated, Liters
Fluoride treatment (expanded bed flow).
120
140
160
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Paul C. Chan, John W. Liskowitz, Mung-Shium Sheih, and Richard Trattner are
with the New Jersey Institute of Technology, Newark, NJ 07102.
Mary K. Stinson is the EPA Project Officer (see below).
The complete report, entitled "Polishing Industrial Waste Stream Effluents Using
Fly Ash-Natural Clay Sorbent Combination," (Order No. PB 83-259 663; Cost:
$10.00, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield. VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Industrial Environmental Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
USS ENVIR2PROTECTION AGENCY
CHICAGO IL 60604
U.S. GOVERNMENT PRINTING OFFICE: 1964-759-102/841
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