United States ,
                   Environmental Protection
                   Agency
Water Engineering Research
Laboratory
Cincinnati OH 45268
                   Research and Development
EPA/600/S2-85/096  Sept. 1985
c/ERA         Project  Summary
                   Application of Adsorptive/
                   Absorptive Resins  and
                   Membranes  for Toxic  and
                   Hazardous Waste  Reduction
                   J. Carl Uhrmacher
                     A study was undertaken to assess the
                    use of membrane separation and ion
                    exchange/adsorption resins for reduc-
                    ing or eliminating toxic and hazardous
                    wastes in the metal finishing and muni-
                    tions  manufacturing industries. Data
                    were gathered by means of a literature
                    review and  personal interviews with
                    leading researchers in the field.
                     The study examined the capabilities
                    of adsorptive and ion exchange systems
                    using conventional resins, and it also
                    evaluated the newer ion selective and
                    macroreticular non-ionic resins. Similar
                    evaluations were made for the mem-
                    brane separation processes based on
                    the use of conventional size exclusion.
                    ion exchange film-type membranes, and
                    experimental liquid membranes.
                     The process streams and operations
                    involved in the metal finishing and
                    munitions manufacturing industries
                    were studied in detail. All of the impor-
                    tant chemical species normally found in
                    aqueous solutions throughout the plants
                    were identified. Also documented are
                    other chemical and physical character-
                    istics of these streams such as the pH,
                    suspended solids, and the presence of
                    strong oxidizing or reducing agents.
                     The treatment problems encountered
                    in the two industries are quite different,
                    since the species to be removed from
                    the metal finishing wastes are.primarily
                    ionic, whereas the wastes from the
                    munitions industry contain mostly non-
                    ionic, nitrated organic compounds. Both
                    the membrane separation and ion ex-
                    change/adsorption resin systems are
                    evaluated relative to the specific char-
acteristics of the hazardous materials to
be removed.

  This Project Summary was developed
by EPA's Water Engineering Research
Laboratory. Cincinnati. OH. to an-
nounce key findings of the research
pro/act that is fully documented in a
separate report of the same title (see
Project Report ordering information at
back).

Introduction
  This study was conducted to assess the
state of the art of commercially available
and developing technologies for reducing
or eliminating hazardous materials from
liquid wastes generated in the metals
finishing and munitions manufacturing
industries.  The study examines  mem-
brane separation systems and ion ex-
change/adsorption resin systems  for
purifying these industrial wastewaters.

Toxic and Hazardous
Wastes in the Metal Finishing
Industry
  The metal finishing industry uses more
than 100 surface finishing and fabricating
processes that require aqueous applica-
tion and removal of metals. Wastewaters
from  metal finishing processes contain
heavy metal cations that may be toxic and
anions that are also a potential hazard to
the environment. In addition to the ionic
species, organic molecules used as bright -
eners, cleaners, and chelating agents are
also  present and can complicate the
wastewater treatment process. Potential

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pollutants in metal finishing wastes are
listed in Table 1.

Hazardous Wastes in the
Munitions Industry
  The common explosives produced by
the  munitions industry contain nitro
groups  attached  to  a  wide variety of
organic structures, which can be aromatic
(benzene ring  type),  heterocyclic (rings
containing non-carbon atoms),  or ali-
phatic (straight or branched chains). The
munitions industry also produces nitrated
organic compounds of mercury and lead
that are used as primers for explosives or
propellants. Typical  hazardous wastes
from Army munitions operations are as
follows:

RDX  (Hexahydro-1,3,5-trmitro-
      1,3,5-tnazme)
HMX (Octahydro-1,3,5,7-tetranitro-
      1,3,5,7-tetrazocme)
TNT  (Trinitrotoluene)
DNT  (Dmitrotoluene)
NT    (Nitrotoluene)
TAX  (1 -Acetyl-1,2,3,4,5,6-hexahydro-
      3,5-dmitro-1,3,5 triazme)
SEX  (1-Acetyl-1,2,3,4,5,6,7,8-
      octahydro-3,5,7-trinitro-1,3,5,7-
      tetraazocine)
PETN (Pentaerythntol tetranitrate)
Tetryl (N-Methyl-N,2,4,6-
      tetranitrobenzenamine)
Nitroglycerin
Nitrocellulose
Nitroguanidine

PRIMERS
Lead Styphnate Pb (C6HN3O8)
Lead Azide  N6Pb
Mercury compounds
  Two particular effluents from the man-
ufacture and processing of TNT (trinitro-
toluene) and TNT-containing  ordnance
constitute  a  significant  problem. Red
water is a  darkly colored solution that
results from selite processing of TNT to
remove  unwanted isomers and byprod-
ucts. This solution can be concentrated
and  used  as an additive  in the paper
industry or disposed  of by incineration.
Further  washing of the partially purified
TNT produces the more dilute and lighter
colored  solution termed  "pink water."
Pink water is also produced as a result of
general cleaning and washing operations
throughout the  plant  when the carrying
stream has a neutral or alkaline pH and is
exposed to sunlight. LAP (load, assembly,
and pack) plants, where artillery shells
are cleaned by steam and repacked with
fresh explosives, also produce pink water.
This  waste stream  contains  RDX and
HMX, two  heterocyclic  nitrated  explo-
sives, as well  as TNT.
  The wastewaters encountered in these
two  industries are  quite different in
physical and chemical characteristics and
also  in the  type of hazard they present
relevant to the general population and to
the environment. In metal finishing, the
species  to  be  removed are ionic and
amenable to treatment based on either
ion exchange or membrane-type separa-
tion  techniques. The munitions waste-
waters contain mostly non-ionic, nitrated
organic compounds  that have so  far
resisted ion  exchange treatment. The
various organic compounds encountered
should be able to be concentrated through
the use of reverse  osmosis  or  even
ultrafiltration  membrane systems,  since
these separation techniques are based on
size  discrimination. Removing  organics
from aqueous streams with adsorptive
materials such  as  activated carbon is
quite common,  and resin systems with
high adsorption  capacities, such as those
Table  1.   Potential Pollutants in Metal Finishing Wastes
Cations (Valence)
Cr (+3 +6)
CuM +2)
Ni(+2+3)
Sn (+2 +4)
Pb (+2 +4)
Au f+1 +3;
AgM)
Zn (+2)
Anions (Valence)
Cr207 (-2)
CNf-1 )
SO. (-2)
BFt(-1)
Clf-1)
SiOe (-2)
P207<-4)

Other Materials
Organics
Brighteners
Cleaners
Chelates
Detergents



         Cd(+2]
with macroreticular resins, should have
the potential for  treating  munitions
wastes.

Use of Membrane Separation
Systems
  Osmotic membranes have been a lab-
oratory  curiosity since the 1920's, but
practical membranes were not commer-
cially available until the 1 960's. The full
report evaluates the classic thin-skinned
polymeric membranes used in ultrafiltra-
tion and reverse osmosis systems today,
and it examines dynamic inorganic mem-
branes.  The full report  also evaluates
processes that use ion exchange mem-
branes,  such as electrodialysis and Don-
nan dialysis. Finally, the  full report con-
siders potential applications of an emerg-
ing liquid membrane technology that uses
both supported and emulsion liquid mem-
branes.

Use of Resin Systems
  A wide range of ion exchange/adsorp-
tion-type resins have been used in indus-
trial water purification systems over the
years. The new  types of  resins being
developed for both ion  exchange  and
adsorption applications are presented in
this report. Both microreticular  and macro-
reticular divinylbenzene/polystyrene res-
ins are included.  Also  examined are
chelating and reductive resins that react
with the metallic ions. Finally,  recently
developed ion exchange precoats are
examined for potential applicability.

Methods

Sources of Information
  A wide range of publications dealing
with the  separation sciences was re-
viewed to develop a list of experts from
industry, government, and academia who
would  be knowledgeable in this field.
Appropriate trade publications were re-
viewed  to identify companies actively
engaged in metal  finishing,  munitions
manufacturing, producing  or supplying
membranes or membrane separation
systems, producing or  supplying ion
exchange/adsorption resins or treatment
systems, or conducting research in these
areas.

Evaluation of Information
  Information from these  sources  was
compiled to give an overall history and
general picture of the state of the art for
the different types of membrane separa-
tion and ion exchange/adsorption resin
systems. The data  available on the per-

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formance of  individual products  in the
treatment of hazardous wastes from the
metals finishing and  munitions manu-
facturing industries were then evaluated
Combined information from all of these
sources was then assessed to determine
the potential of these technologies in the
treatment of waste streams  from the
target industries.

Results
  A considerable body of data and tech-
nical information was compiled as a result
of the  literature .review, telephone and
personal interviews, and visits to various
research facilities. The data are present-
ed'primarily ir> the  form  of tables that
describe  (1) the characteristics of the
various waste streams and plating solu-
tions encountered in the metal finishing
and munitions manufacturing industries,
and (2) the performance characteristics of
specific types of membrane  separation
systems, membrane materials, commer-
cial membrane modules, ion exchange/
adsorption systems,  resin  materials, and
commercially  available resin formula-
tions.
  The full report presents a  complete
discussion of data available on the com-
mercial uses of these wastewater treat-
ment technologies and for the treatment
of similar aqueous solutions. In addition,
the full report reviews and evaluates the
results of advanced research projects  on
the development of new or novel  mem-
brane systems and  resin formulations
that are potentially applicable to the
treatment of these wastes. The conclu-
sions and recommendations presented in
the report are based on assessment of the
accumulated data.

Conclusions

Treatment of Metal Finishing
Wastes

Use of Ion  Exchange Resin
Technology
  Ion  exchange  resin  technology is a
mature technology for the removal  of
contaminants from plating solutions, the
recovery of  precious  metals, and the
freshening of plating baths for reuse. This
technology is being used by both manu-
facturers  and firms that collect and
rejuvenate spent solutions from  small
companies. Research is being performed
by private industry and government on
process improvements  in areas such  as
producing  more highly  selective resins
and developing better  removal and re-
covery techniques. The economics of
using ion exchange  technology in the
treatment of these wastes varies widely
for specific applications, depending on
the type of plating system involved, the
configuration of rinses, and the configura-
tion of the waste treatment system.

Use of Membrane Technology
  Reverse osmosis and ultrafiltration are
mature technologies  for treating metal
finishing wastes. Zero-sludge and re-
duced-sludge systems are available and
are used  extensively throughout the
industry. Reverse  osmosis has a partic-
ularly high utilization rate in the treatment
of nickel plating wastewaters.
  Although zirconium  oxide dynamic
membranes are commercially available
and appear promising, they have not been
used  to any extent in the treatment of
hazardous wastes. The newer membrane
separation systems based on liquid and
ion exchange membranes, Donnan dial-
ysis, and emulsion liquid membranes are
not sufficiently developed to assess their
potential for application to the treatment
of hazardous wastes.
  The economics  of using membrane
separation  systems in the treatment of
these wastes generally depends on:

• the amount of water to be treated,
• the fouling index (SDI) of the water to
   be  treated,
• pretreatment requirements for the
   wastewater before introduction to the
   membrane separation process, and
• the potential for resource recovery.

  Potential savings and capital payback
depend on.

• the value of recovered materials,
• the potential for reusing  the treated
   water in the process,
• potential reductions  in sewer dis-
   charge charges, and
• potential savings in sludge removal
   and disposl charges.

  Electrodialysis  and other  electrolysis
processes have been used to a moderate
degree in the treatment of these waste
streams.  Supported liquid  membranes
have been demonstrated in the field and
show some promise, and the combination
of Donnan  dialysis with other technol-
ogies  has demonstrated potential for the
treatment of  these wastes.  However,
insufficient data are available at this time
to assess the potential economics of these
systems in the treatment of metal finish-
ing wastes.
  Of the various pollutants from electro-
plating processes, hexavalent chromium
is probably the most difficult material to
treat, since it is an anion and a powerful
oxidizing agent. Claims of successful
treatment have not been fully substan-
tiated by the data available at this time.

Treatment of Munitions Wastes

Use of Ion Exchange/Adsorption
Resin Technology
  Granular activated  carbon (GAC) has
been shown to be more cost effective in
the treatment of munitions wastes than
currently available macroreticular resins.
However, recent laboratory studies indi-
cate that the use of these resins in a two-
bed system has significant potential for
being more cost effective than GAC mthe
future.

Use of Membrane Technology
  Very little effort has been made to apply
membrane separation technology to the
treatment of wastewaters from the muni-
tions  manufacturing  industry. Concern
over the potential for accumulating dan-
gerous concentrations of explosive mater-
ials has been a major  impediment to
research in this area. Also, very little work
has been  done on  the application of
membrane separation technology for
treating the unique wastes from military
installations. Although the data available
indicate mixed results, this technology is
considered to have a high potential for the
treatment of these wastes in the future.
  The full report was submitted in fulfill-
ment  of Contract No.  68-03-3214 by
Carltech Associates, Inc., under the spon-
sorshipof theU.S. Environmental Protec-
tion Agency.

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    J. Carl Uhrmacher is with Car/tech Associates, Inc., Columbia, MD21045.
    Thomas J. Powers is the EPA Project Officer (see below).
    The complete report, entitled "Application of Adsorptive/Absorptive Resins and
      Membranes for Toxic and Hazardous Waste Reduction," (Order No. PB 85-241
      776/AS; Cost: $13.00, subject to change) will be available only from:
            National Technical Information Service
            5285 Port Royal Road
            Springfield, VA22161
            Telephone: 703-487-4650
    The EPA Project Officer can be contacted at:
            Water Engineering 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

EPA/600/S2-85/096
        QOOO'529   PS
        CHICAGO
                       PROTECTION  AGENCY

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