United States
                   Environmental Protection
Industrial Environmental Research
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
                   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
                     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
                     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
  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

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

  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

Materials and Methods

  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
Sample 1
Sample 2
Sample 3
  The  investigation was performed  in
three different phases: (1) static studies,
(2) dynamic studies, and (3) spent sorbent
  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



               Wastewater Concentration = 4.0 mg/l
              •  Bentonite

              A  Bauxite

              •  Fly Ash (Acidic)

              •  Fly Ash (Basic)
     O  //lite

     A  Kaolinite

     •»•  Zeolite
     O  Vermiculite
                    20          4O          60           80
                        Sorbent Concentration in Wastewater, g/l
Figure 1.    Fluoride treatment (batch conditions).
determine that mixture's effectiveness in
reducing both  fluoride  and  iron  to
acceptable levels under dynamic (flowing)

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.

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-

1   0.2
                                   Influent concentration =1.8 mg/l

                                   %  Fly Ash (Acidic)

                                   •  Fly Ash (Basic)

                                   A  Kaolinite

                                   D  ////te
Figure 2.
               20           40           60          SO

                     Sorbent Concentration in Wastewater, g/l

      Iron treatment (batch conditions).
   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.

  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.

                                      D  Illite
                                      A  Kaolinite
Figure 3.     pH effect on sorbent capacity for fluoride (batch conditions).

•   12
§   4
           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
Figure 4.    Fluoride removal dependence on sorbent particle size (gravitational flow).
                    Influent Concentration = 5.8 mg/l
Figure 5.
                     60        80        100
                     Volume Treated, Liters
Fluoride treatment (expanded bed flow).

      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
Center for Environmental Research
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
       CHICAGO  IL  60604
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