EPA-600/2-77-104
June 1977
Environmental Protection Technology Series
             OZONE TREATMENT OF  CYANIDE-BEARING
                                            PLATING WASTE
                                         I
                                         55
                                         o
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                         CD
                                     Industrial Environmental Research Laboratory
                                          Office of Research and Development
                                         U.S. Environmental Protection Agency
                                                  Cincinnati, Ohio 45268

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                  RESEARCH REPORTING SERIES

  Research reports of the Office of Research and Development, U.S. Environmental
  Protection Agency, have been grouped into nine series. These nine broad cate-
  gories were established to facilitate further development and application of en-
  vironmental technology. Elimination of traditional grouping was consciously
  planned to foster technology transfer and a maximum interface in related fields
  The nine series are:

       1.  Environmental Health Effects Research
       2.  Environmental Protection Technology
       3.  Ecological Research
       4.  Environmental Monitoring
       5.  Socioeconomic Environmental Studies
       6.  Scientific and Technical Assessment Reports (STAR)
       7.  Interagency Energy-Environment Research and Development
       8.  "Special" Reports
       9.  Miscellaneous Reports

  This report has been assigned to the  ENVIRONMENTAL PROTECTION TECH-
  NOLOGY series. This series describes research performed to develop and dem-
  onstrate instrumentation, equipment, and methodology to repair or prevent en-
  vironmental degradation from point and non-point sources of pollution. This work
  provides the new or improved technology required for the control and treatment
  of pollution sources to meet environmental  quality standards.
This document is available to the public through the National Technical Informa-
tion Service. Springfield, Virginia 22161.

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                                             EPA-600/2-77-104
                                             June 1977
OZONE TREATMENT OF CYANIDE-BEARING PLATING WASTE
                       by

                L. Joseph Bollyky
              PCI Ozone Corporation
                      for
              Sealectro Corporation
               Mamaroneck, New York
               Project No.  R802335
                 Project  Officer

               Herbert  S.  Skovronek
      Industrial  Pollution Control Division
   Industrial Environmental Research Laboratory
             Cincinnati,  Ohio 45268
  INDUSTRIAL ENVIRONMENTAL RESEARCH LABORATORY
       OFFICE OF RESEARCH AND DEVELOPMENT
      U.S. ENVIRONMENTAL PROTECTION AGENCY
             CINCINNATI, OHIO 45268

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                                 DISCLAIMER
    This report has been reviewed by the Industrial Environmental Research
Laboratory-Cincinnati, U.S. Environmental Protection Agency,  and approved for
publication.  Approval does not signify that the contents necessarily reflect
the views and policies of the U.S. Environmental Protection Agency,  nor does
mention of trade names or commercial products constitute endorsement or re-
commendation for use.
                                     ii

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                                  FOREWORD

      When energy and material resources are extracted, processed, converted,
and used, the related pollutional impacts on our environment and even on our
health often require that new and increasingly more efficient pollution con-
trol methods be used.  The Industrial Environmental Research Laboratory -
Cincinnati (IERL-CI) assists in developing and demonstrating new and im-
proved methodologies that will meet these needs both efficiently and
economically.

      This full scale demonstration of a highly automated ozonation system
for the destruction of cyanide in electroplating wastewaters will help to
establish the technical and economic feasibility of this alternate technol-
ogy.  Such information will be of value both to EPA and to the industry
itself.  Within EPA's R&D program the information will be used as part of
the continuing program to develop and evaluate improved and less costly
technology to minimize industrial waste discharges.  Besides its direct
application to cyanide wastes from electroplating, this technology may find
application in the control of cyanide from other sources as well as for
the destruction of carbonaceous pollutants generated by a host of other
industries.

      For further information concerning this subject the Industrial Pollu-
tion Control Division should be contacted.
                                            David G. Stephen
                                                Director
                               Industrial Environmental Research Laboratory
                                                Cincinnati
                                    iii

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                                   ABSTRACT


      A plating waste treatment plant was built to demonstrate the effective-
 ness of ozone treatment for the oxidative destruction of cyanides and cya-
 nates and for the removal of copper and silver as their oxides on a plant
 scale.  The plant was designed to treat all the waste from copper, gold, and
 silver plating operations.

      A 9-month study was carried out to evaluate the effect of process param-
 eters, to identify and optimize key parameters, to establish capital cost and
 operating costs, and to explore the possibility of producing an effluent of
 the highest quality.

      The results of the study clearly show that ozone treatment rapidly and
 economically destroys copper and sodium cyanides.  The reaction first pro-
 duces cyanates,  which are oxidized further by ozone and simultaneously,  but
 much more slowly, hydrolyzed.   Although the complete removal of cyanates was
 demonstrated,  it was not practiced under optimum conditions since it is  not
 required under local or Federal standards.   The process precipitates copper
 and silver in a  readily settleable form.   The oxidation of copper cyanide is
 more rapid and requires less ozone than that of sodium cyanide.

      Cost data have been developed to reflect the optimum operating condi-
 tions found experimentally.   The plant treats a combined cyanide (alkaline)
 and heavy metal  (acidic)  flow of 185,000 I/day(49,000 gal/day).   The costs
 of treatment are as follows:

             operating cost         $  0.27/1,000 1 ($1.03/1,000  gal)
             total cost              $  0.35/1,000 1 ($1.31/1,000  gal)

 The costs  of ozone treatment of the cyanide  waste alone are as  follows:

             operating cost         $  0.38/1,000 1 ($1.43/1,000  gal)
             total cost              $  0.62/1,000 1 ($2.35/1,000  gal)
                                    $10.34/kg CN   ($4.70/lb CN)

Capital investment  for this optimized  system is estimated as $51,200.

     This report  was  submitted  in  fulfillment  of  Demonstration Grant  #8802335
by Sealectro Corp. under the partial  sponsorship  of the U.S. Environmental
Protection Agency.  Work carried out by PCI  Ozone Corp. under contract to
Sealectro Corp. covers the period April 1, 1973 to June 30,  1974 and  the
project was completed January 31,  1975.
                                      IV

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                                  CONTENTS

 Foreword	          „.
 Abstract	'.'.'.	   i
 Figures  	  .....!!..!      v
 Tables   	                      	    .
                      	•	   vi
 Acknowledgment 	                   ..

      1.   Introduction	            -i
      2.   Conclusions   	*	    c
      3.   Recommendations	            '      /•
      4.   Design of  Treatment  Plant	'.'.'.'.'.'.'.    1
      5.   Study Objectives  and Approach	'.'.'.   13
      6.   Operation  Under Optimum  Conditions	!  !  !  ! !   16
      7.   Study of Process  Parameters	]   19
      8.   Treatment  of Sodium  Cyanide	'  \          28
      9.   Discussion	      ....
    10.   Cost  Evaluation	'..'.'.'.'*'   33
    11.   Analytical Methods   	  ;...!****   38

References	                    ,,


                                 FIGURES


Number                                N                                 Page

   1       Flow Diagram - Sealectro Plating Waste Treatment Plant  .  .    8

   2       Sealectro Plating Waste Treatment Plant   	   11

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                                  TABLES

Number                                                                Page

   1      Plating Waste Effluent Limitations	   3

   2      Monthly Average Concentrations of Contaminants  	   4

   3      Ozone Treatment of Plating Waste, Typical Operation
               Conditions	17

   4      Ozone Treatment of Plating Waste (Copper Cyanide Complex)
               Under Upset Operating Conditions 	  20

   5      Ozone Treatment of Plating Waste, Less Than Stoichiometric
               Ozone Dosage	21

   6      Ozone Treatment of Plating Waste (Copper Cyanide Complex)
               With Small Excess of  Ozone	22

   7      Ozone Treatment of Plating Waste (Copper Cyanide Complex)
               With Excess Ozone	23

   8      The  Effect of  Ozone Dosage at  Low Concentrations of Cyanide  24

   9      The  Effect of  Ozone Dosage on  Intermediate  Concentrations
               of  Copper Cyanide	25

  10      The  Effect of  Ozone Dosage on  High Concentrations  of
               Copper Cyanide 	  25

  11      The  Effect of  Cyanide  Concentration at  Constant  Ozone  to
               Copper Cyanide Ratios 	  26

  12      Ozone Treatment  of  Sodium  Cyanide on  Plant  Scale 	  29

  13      Capital  Cost of  Ozone  Treatment	34

  14      Weekly Operating Cost  for  Ozone  Treatment 	   35

  15      Treatment  Costs	36

  16      Cyanide Destruction  Costs  $ 	  .....,..,,   37
                                    >$
  17      Analytical Methods  	   39
                                   vi

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                               ACKNOWLEDGMENT


          PCI Ozone Corp. is grateful for the support and cooperation extend-
ed by Mr. George E. Mohr, Frederick Baron, and Jesse Fuchs of Sealectro Corp,

          This project was carried out with the partial support of the U.S
Environmental Protection Agency.  The guidance and assistance of the Project
Officer, Dr. H.S. Skovronek, of the Industrial Environmental Research Labora-
tory- Cincinnati, is acknowledged.

          Credit is due to Mr. Charles Ballnt (PCI) for the operation of the
treatment plant during Che study program and to Mr. Barry Siegel (PCI) for
the analysis of the samples.
                                    vii

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                                  SECTION 1

                                 INTRODUCTION
     The electroplating industry produces substantial quantities of waste-
 ™^r ?°nta*nin8 cyani
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some of these studies appear to be contradictory because the experiments were
carried out under different, non-comparable reaction conditions.   Neverthe-
less, it is clear from such studies that mass transfer of ozone from air to
water controls the reaction rate in most cases (11,12).  In a batch reactor
study, the pH of the solution changes drastically during ozonation, first de-
creasing to an acidic pH, then increasing to a basic pH again as the oxida-
tion of cyanide progresses through cyanate and then to what was believed to
be urea and ammonium nitrate (11).  More recent work (lib) projects that the
products are carbon dioxide and nitrogen.  Certain metal salts, such as those
of copper, appear to catalyze the oxidation reaction when mass transfer is
not the limiting factor  (12).  The oxidation of certain hard-to-oxidize com-
plexes of cyanide such as sodium ferricyanide is accelerated by ultraviolet
(uv) irradiation, heating to 83°C (180°F) or both (21).

     The stoichiometry of the reaction has been studied under two sets of
different reaction conditions (11,13).  From these studies, it appears that
the number of moles of ozone required for the destruction of one mole of cya-
nide is dependent on cyanide concentration, on ozone concentration and on pH.
These findings suggest the presence of competing side reactions.  In general,
higher cyanide concentrations, higher ozone concentrations, and higher rates
of ozone mass transfer favor lower ozone dosage for cyanide destruction.

     Oxidation-reduction potential measurements (ORP) were found to be a
good indication of the progress of the ozone/cyanide reaction  (11).

     A laboratory study  preceding this demonstration project clearly estab-
lished that the oxidation of cyanides by ozone destroys both cyanides and
cyanates.  That is, the  reaction does not stop at the cyanate  stage.  Fur-
thermore, the ozone treatment precipitates copper and silver as a dense,
readily filterable or settleable precipitate which is believed to be com-
posed primarily of the metallic oxides  (6).

THE  PLATING OPERATION AT SEALECTRO CORPORATION

     Sealectro Corp., a  manufacturer of  connectors and other related com-
ponents for the electronics  industry, decided to build a  new plating plant
to satisfy its requirements  internally  in  the gold,  silver, copper and nick-
el plating area.  The plant was designed in-house and  installed by Sealec-
tro *s maintenance personnel.

     The  expected wastewater  flows from the  plant, based  on design, were as
follows:

a)   Alkaline cyanide flow:   25.5 1/min (6.75 gpm) with  surges to  39.0  1/min
      (10.4 gpm) containing  contaminants in the  following  maximum concentra-
     tions  (mg/1) :

                                cyanide	60
                                copper	32
                                silver	  3.4

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b) Acidic wastewater flow: 60 1/min (16 gpm) with surges to 93.0 1/min
   containing contaminants in the following maximum concentrations (mg/1):

                               nickel	14
                               tin	 2
                               lead	 0.08

     In order to be discharged, the treated effluent had to meet or exceed
the requirements of Act. No. 27-1968, County Public Works Sewer Ordinance
No. 1, Board of Supervisors of Westchester County, N.Y., effective May 20,
1968, which may be summarized as follows:

          1. pH in the range of 5.5 to 9.5
          2. temperature not to exceed 65°C (150°F),
          3. maximum concentration of toxic substances (mg/1):

                              copper	    3.0
                              cyanate	   10.0
                              cyanide	    1.0
                              nickel	   10.0
                              silver	    0.05
                              chlorine	  100.0

     After the construction of the Sealectro Plating Waste Treatment Plant,
the EPA published guidelines and standards on March 28, 1974  (Federal Regis-
ter, Vol. 39, No. 61, covering the waste treatment requirements for the plat-
ing industry). The permissible amounts of pollutants are related to the sur-
face area plated as summarized in Table 1.

                TABLE 1.  PLATING WASTE EFFLUENT LIMITATIONS

             Best Practicable Technology Currently Available, 07/01/77

         Parameter                      Effluent  (mg/m2)
                               1 day max.           30 day avg. max.

         Cu                        160                     80
         Ni                        160                     80
         Cr  (VI)                    16                      8
         Cr, total                 160                     80
         Zn                        160                     80
         CN A*                      16                      8
         CN! total                 160                     80
         TSS                      4800                   3200
         pH                      6.0-9.5                6.0-9.5
*CN, A means chlorine-oxidizable cyanides.

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     A monthly average rinse water flow of 80 1/m2 (1.96 gal/ft ) of plated
surface is assumed with a one day maximum of 160 1/m  (3.93 gal/ft2).  On
the basis of 80 1/m2 (1.96 gal/ft2) the concentrations of contaminants per-
mitted were calculated as shown in Table 2 for BPTA.

          TABLE 2.  MONTHLY AVERAGE CONCENTRATIONS OF CONTAMINANTS*

                                                      BPTCA
                      Pollutant                Effluent Parameters
             	(mg/1)

             Cyanide (Dest. by Cl)                      0.1
                    Total                               1.0
             Copper                                     1.0
             Iron                                       2.0
             Lead                                       1.0
             Nickel                                     1.0
             Silver                                     0.1
             Tin                                        2.0
             Zinc                                       1.0
             TSS                                       40.0
             pH (avg. Daily Discharge)                  6.0-9.5

            *Based on 80 1/m2 flow and 30 day average maximum
             discharge rates.

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                                  SECTION 2

                                 CONCLUSIONS
     The Sealectro demonstration project achieved its major objectives.  It
has demonstrated on a plant scale the effectiveness of ozone for cyanide and
cyanide-bearing plating waste treatment.  It has confirmed the results of
laboratory work in the laboratories of PCI Ozone Corp. in Stamford, Connecti-
cut* concerning the removal of cyanide, cyanate, copper, and silver by ozone
treatment.

     The major results of the study may be summarized as follows:

a)   Optimum operating conditions were determined for the Sealectro Plant to
     be 1 to 1.5 moles of ozone/mole CN~at a pH of 7 to 9.5 in the ozone
     contactor and a final clarifier pH of 9 to 9.5 at ambient temperatures
     of 14 to 20°C  (57 to 68°F).

b)   It was established that the ozone dosage is the most critical operating
     parameter, with 1 to 1.5 moles 0,/mole CN**found to be optimum at low
     CN~concentrations (<20 mg/1) and 1.8 to 2.8 moles 0_/mole CN'at higher
     levels (>40 mg/1).

c)   The pH of the cyanide waste in the ozone contact tank was found to have
     no significant effect in the range of 7 to 10, thereby eliminating the
     need for precise pH control during ozone treatment.

d)   Firm cost data were established based on plant experience. ^Treatment
     operating cost was $0.38/1000 liters ($1.43/1000 gal) of CN influent
     and $0.27/1000 liters ($1.03/1000 gal) total wastewater.  The total
     capital costs were $66,613.00 for the Sealectro installation but are
     estimated at $51,200 for an optimized, non-research installation.

e)   The ozone treatment proved to be a safe operation.  It did not emit
     ozone into the atmosphere.

f)   Side benefits of ozone treatment include improved safety by eliminating
     the need for the transportation and storage of toxic and hazardous
     chlorine or hypochlorite and, in general, a sophisticated and highly
     automated operation requiring a minimum of attention and chemical ad-
     ditions.


*Now located in West Caldwell, N. J.

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                                 SECTION 3

                              RECOMMENDATIONS

     The Sealectro demonstration project achieved its major objectives and
clearly demonstrated that ozone treatment is an effective, economical and
safe method for cyanide plating waste treatment.  We recommend a further
demonstration study covering the following areas.

     Recycling of treated effluent into the plating process should be pos-
sible by providing a small increase in ozone dosage, eliminating cyanide from
the acid flow* and improving the operation of the settling tank.  The efflu-
ent is suitable as is for the cooling of operating machinery, such as ozone
generators, air conditioners, etc.

     Other metal complexes of cyanide should also be responsive to ozone
treatment.  These metal complexes include those of cadmium, zinc, and iron.
(The removal of the iron complex, a particularly stable one, may require
simultaneous ultraviolet irradiation or elevated temperatures).

     The severity of treatment conditions should be determined for each metal
complex anticipated in a plating plant.
 Cyanide was discovered  in  the  acid  stream of the Sealectro Plating Plant
 and ultimately  found to be due to plumbing and maintenance difficulties.
 The problem was only partially resolved  during the  course  of the  study pro-
 gram.

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                                   SECTION  4

                          DESIGN OF  TREATMENT  PLANT


     The  plating wastewater  treatment plant was designed and installed by
 PCI Ozone Corp. under the direction  of Dr. L.  J. Bollyky.  It was started up
 in January  1974, placed  into full  operation February  25, 1974 and has been
 in operation  since  that  date with  no design or operation-related downtime.

     The  Sealectro  Plating Waste Treatment Plant is designed to treat the
 two wastewater streams produced during the plating operations of the Sealec-
 tro Corp. Plating Plant.  The expected discharges from the plating plant are
 as follows:

     Alkaline cyanide wastewater:  Flow under  normal  conditions, 25.5 1/min
     (6.75  gpm), with provision to accept surges in flow (spills, bath dis-
     charges, etc.) or growth to 39  1/min  (10.4 gpm).  The wastewater con-
     tains  cyanide  up to 60  mg/1,  copper up to 32 mg/1, silver up to 3.4 mg/1,

     Acid waste:  Flow under normal  conditions, 60 1/min (16 gpm), with provi-
     sion to accept surges in the  flow or growth to 93 1/min (24.6 gpm).
     This flow may  contain nickel  up to 14 mg/1, tin  up to 10 mg/1, and lead
     up to  .08 mg/1 concentrations.

The combined average flow of acid  and cyanide  waste is 86 1/min (22.75 gpm),
with provisions to  accept surges in  flow rates up to  a total of 132 1/min
 (35 gpm) flow.  Peaks and surges are to be equalized  in separate underground
holding tanks.

     The plant is designed to operate continuously around the clock, if
necessary.  The flow of both  wastewater streams is controlled automatically,
as is the pH of the cyanide  stream and of the  effluent from the treatment
plant.   The ozone dosing rate is also controlled automatically by on-line
monitoring of residual ozone.

     Flexibility was engineered into the plant and numerous sampling points
were provided to allow for experimentation and modifications necessary for
the demonstration study.  Thus, this plant is  over-designed to allow varia-
tion of process parameters over a broad range.

     The general design of this wastewater treatment plant is shown in the
flow diagram, Figure 1.   The  plant has two separate underground storage tanks
to receive and equalize the  segregated wastewaters; a 7500 1 (2000 gal) tank
for the alkaline cyanide waste (T-2), and a 15,000 1  (4000 gal) tank for the

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oo
ALKALINE CYANIDE
WASTE
0-
ACIDIC METAL
WASTE
L"
1<
T-
r- ...... -
t
i 	
iU
^
-2
»
EQUALIZATION
TANK

1 I
T-l

(t)
OZONE
<
1
	 i
T-4
I

DZONE
REACTOR
VENT
¥
^
g
©-
EQUALIZATION
TANK
i 1 J
_ do
1 T-5
NaOH
T-3
CAUSTIC
TANK
1 1 -,
M t "]
T~ C. ' x^x
FINAL
FLASH MIXER \ / LhhLULNI
\/SETTLING
Y TANK
     LEGEND:

        SAMPLE POR'
        THE STUDY "
USED FOR
 m AND
SOLIDS
   FIG, i - FLOW DIAGRAM -SEALECTRO PLATING WASTE TREATMENT PLANT

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 acid wastewater (T-l).  Tank T-2 is provided with a pH sensor, a flash mixer,
 a pump to transfer wastewater into the ozone reaction tank (T-4), and a water
 level sensor.  The pH of the cyanide wastewater is adjusted automatically in
 this tank with 15% caustic from a storage tank (T-3).

      The acid wastewater is received in Tank T-l.  The tank is provided with
 a water level sensor and a pump (P-i) for the transfer of this wastewater
 into the flash mixing tank (T-5) where it is combined with ozone-treated al-
 kaline wastewater from the reaction tank (T-4) to gain all possible neutral-
 ization benefit.

      The PCI Model G-20-M Ozone Generator has an ozone generating capacity
 of up to 9.1 kg/day (20 Ib/day)  of ozone from air under normal operations
 and up to 12 kg/day (26 Ib/day)  of ozone using the auxiliary blower.   The
 auxiliary blower  is part of the PCI Model PRE-23-M Air Preparation Unit.
 The air preparation unit provides the clean, oil free, particle free, dry
 air needed for the generation of ozone.   Oxygen could also be used and the
 output of the same unit would increase twofold.

      The ozone reaction tank (T-4)  is a fiberglass tank of 2250 1 (600 gal)
 capacity.   This tank consists of two major compartments:

      The lower, large compartment where  the wastewater is treated by ozone.
      The ozone is  introduced through porous diffusers at  the  bottom of the
      tank,  which  is filled  with  cyanide-containing wastewater.

      In  the upper,  smaller  compartment  the spent  ozone off-gas  is reintro-
      duced  and either passed through a packed column,  sprayed with the in-
      coming cyanide waste or diffused into the incoming cyanide waste.  In
      either mode of operation, this  upper compartment serves  to remove un-
      reacted ozone  from the off-gases to  assure complete  utilization  of the
      ozone  and to prevent ozone  from escaping to  the outside  atmosphere
      through the vent.

      The fiberglass flash mixer  tank (T-5)  receives  treated alkaline  waste
 from  Reaction Tank  T-4  and  acidic waste from Tank  T-l.  The combined  waste-
 waters are mixed with  the flash  mixer and a final  pH adjustment then  made
 with  caustic or sulfuric acid based  on the  signal  from the pH detector in
 Tank  T-5.  The tank is  covered to prevent splashing  of the wastewater.

      The settling tank  (T-6) receives the neutralized  combined  wastewater
 from  the flash mixer tank (T-5).  The metal  oxides and/or hydroxides  settle
 out in this  quiescent tank  and the clear, treated  water is discharged
 through the  overflow to the sewer.  The solid waste  is removed  manually,  as
necessary, through  a bottom outlet,   as a sludge.  The calculated retention
 time  in the  settling tank is a minimum of 50 minutes.

pH CONTROL SYSTEM

     The pH control system consists of the pH detectors mentioned earlier,
controllers, and tranducers.  All are products of  Foxboro Corp.  This pH  con-
trol system adjusts the pH in Tank T-2 and in Tank T-5 by using a 15%  caustic

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solution held under approximately  52 mm Hg  (10 psig) pressure  in  a pressure
rated  fiberglass  tank  (T-3).  Compressed  air  from  the PRE-23-M Air Prepara-
tion Unit or instrument air from the plant  is used to maintain the pressure
on  the caustic solution in Tank T-3.  The caustic  solution  is  fed into Tank
T-2 and Tank T-5  as needed through pneumatically controlled metering valves
activated by the  pH detectors and  their automatic  controllers.  The caustic
solution is prepared from caustic  flakes  in a separate tank (T-3A) and
pumped into Tank  T-3.

PROCESS CONTROLS

     The process  controls wired into the  central process control  unit allow
either an automatic mode of operation or  manual operation.  All major com-
ponents of this system are fused separately and are wired to permit their
operation independently from the total system in the manual mode  of opera-
tion.  The automatic mode of operation makes use of signals from  level sen-
sors,  located in  Tanks T-l and T-2.  Signals from  these two level control-
lers will operate the pumps to transfer cyanide waste into  Reaction Tank T-4
or  acidic waste into Tank T-5.  The wastewaters flow by gravity from these
tanks  through the rest of the system.  The  ozone output of  the ozone gener-
ator is controlled by an ozone detector which assures sufficient  ozone for
the complete destruction of cyanide in Tank T-4.   If there  is  a wastewater
flow through the  system, both the  ozone generator  and the pH control system
will operate automatically.  A failure of any component, such  as  a pump or
controlling instruments, is indicated by  a visual-audio alarm.

     The waste treatment plant is  separated from the plating facilities and
located ina5.8mx5.8m (19 ft x 19 ft) area with a ceiling height of
4.3 m  (14 ft).   A removable cover  is provided for  the portion of  the roof
directly over the ozone contact tank to permit inside inspection  of this
tank.   The holding tanks (T-l and T-2)  are  located underground  next to the
treatment plant and are accessible through manholes.

LIST OF MAJOR COMPONENTS

     Model G-20-M Ozone Generator  (PCI  Ozone Corp.), with ozone generating
     capacity of 12 kg/day (26 Ib/day)  from air (See Figure 2).

     Model PRE-23-M Air Preparation Unit  (PCI Ozone Corp.), with an output
     of 0.678 m /min (24 scfm),  oil free,  particle free air with a dew
     point of -40 C (-40°F)  or lower.

     Ozone Detector Automatic Controller (PCI Ozone Corp.), one set point
     unit  to maintain  an ozone residual of 0.1 to 2.0 mg/1 in the effluent
     from  the ozone reaction tank,  T-4.

    Ozone  Reaction Tank (PCI  Ozone Corp.) 5.6 m (18.5 ft)  tall,  0.8m (30 in)
    diameter,  two compartment fiberglass  tank,  volume:   2250  1 (600 gal),
    T-4.

    Flash  Mixer  Tank  (PCI  Ozone Corp.),  1.5 m (5 ft)  tall, 0.8 m (30 in)
                                     10

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Figure 2.   Sealectro Plating Waste Treatment  Plant

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diameter, fiberglass covered tank, volume:  700 1 (180 gal), T-5.

Settling Tank (PCI Ozone Corp.), 2.3 m (7.5 ft) tall, 1.8 m (6 ft) di-
ameter, fiberglass tank with conical bottom, volume:  6500 1 (1730 gal),
T-6.

pH Detector and Controllers (Foxboro Corp.)

Central Control Panel (PCI Ozone Corp.).
                                12

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                                  SECTION 5

                        STUDY OBJECTIVES  AND APPROACH


      This  study was  carried  out  to  evaluate the  operation of the plating
 waste treatment plant  and  to confirm laboratory  findings that ozone effec-
 tively destroys both cyanide and cyanate and precipitates copper and silver
 ions  as readily settleable solids (6).

      Further objectives were to  study the effects  of changes in major pro-
 cess  parameters such as ozone dosage, ozone concentration, pH, and temper-
 ature and  to find  the  optimum values for those effects.

      Another objective was to establish  the cost of this plant and of a new
 plant based  on  optimum operating parameters.  Both capital cost and operat-
 ing cost were to be  considered.

 APPROACH

      The study  was carried out in three  phases as  described below.  A major
 constraint placed on the study was  that  it had to  be carried out while the
 plating plant was in full  operation, requiring treatment of plating waste as
 generated.   The plating operation could  not be interrupted for extended
 periods  for  obvious  economic  reasons.

      In  the  first phase of the study, the major  objective was to learn about
 the operating characteristics of the plant and to  resolve any possible prob-
 lems,  that is,  to conduct  a plant shakedown operation.

      Two problems were encountered  during this phase of operation.  The
 first was excessive  wastewater flow from the plating plant due both to im-
proper piping that channeled  cooling water from  air conditioners into the
 system and due  to the simultaneous  shakedown operation of the new plating
plant and the inexperience  of the  new crew.  The  second problem was the
presence of  significant amounts  of  cyanide in the  acid wastewater line, due
again to faulty piping in  the plating plant.

      During  the second phase  of  the  study, the major objectives were to
evaluate the  effect  of process parameters and to determine optimum condi-
tions, while  still providing uninterrupted waste treatment for the plating
plant.

     To accomplish these objectives, the  treatment process parameters were
varied by upsetting  the waste treatment  plant's operation temporarily  and
their effects evaluated as follows:

                                     13

-------
  a)    Cyanide  concentrations were  adjusted by adding  concentrated plating
       solution to  the  cyanide waste holding  tank.  The plating plant tended
       to  produce wastewater with a high  flow but with low cyanide concentra-
       tion because of  the earlier  noted  problems.  In order to evaluate
       treatment in the higher (20  to  100 mg/1) cyanide concentration range,
       plating  solution had to be added.

  b)    Ozone dosage was adjusted upward by increasing  the output of ozone or
       downward by  adding concentrated plating solution to the underground
       cyanide  waste holding tank,  thereby changing both cyanide concentra-
       tions and ozone/cyanide ratio.

  c)    pH  was adjusted in the cyanide  holding tank or  in the flash mixer and
       thereby,  in  the settling tank,  independently.

  d)    The temperature changed naturally  as the study  progressed through
       spring,  summer, fall, and winter.  It  did not produce a noticeable ef-
       fect over the observed range of 14 to  20 C (57  to 68 F).

  e)    Experimental  treatment of sodium cyanide was carried out during a sum-
       mer plant shut-down of the plating plant to obtain background data.

       The temporary large upset of certain process parameters such as cyanide
  concentration  and  ozone dosage could only be maintained for about three
  hours without  affecting plating plant operation.  Nevertheless, this time was
  sufficient to  obtain useful data from the ozone contact tank; however, equi-
(J.ibrium  conditions were not always established in the settling tank.  There-
  fore, metal concentration values obtained for the final effluent under these
  conditions should  be treated with caution.   They probably reflect maximum
 values.

      During the third phase of the study,  the treatment plant was operated
 under optimum  (or  close to optimum)  conditions for extended periods to ob-
 tain data for process and cost evaluation.   These results are compiled and
 discussed later.   Although the plating plant operates within the limits of
 local and EPA standards for a small  plating operation,  it produces a large
 flow of wastewater, far in excess of what  would be permitted by the EPA from
 a large plating operation.   In addition, the acid waste flow,  which should
 have contained no cyanide,  carried a cyanide concentration of 0.3 to 1.0
 mg/1.  Sealectro Corp. made repeated attempts to eliminate cyanide from the
 acid flow by checking piping and floor cracks in the plating plant and by
 tightening housekeeping operations.   As a  result,  the cyanide concentrations
 in the acid stream were lowered slightly to 0.2 to 0.8 mg/1.   No further
 improvements  were made during the course of the study because of pressing
 need for production and other economic reasons.   Because of the time limita-
 tions of this EPA study,  the third or final phase of this project was  com-
 pleted under  these conditions.   The  data presented in Section 6 show the re-
 sults on that basis,  as  well as residual cyanide analyses of the effluent
 from the ozone contact tank  (T-4).  The cyanide concentration in the efflu-
 ent from the  ozone contact  tank could consistently be reduced to 0.8 mg/1.

-------
     The analyses of the samples were carried out in the laboratories of PCI
Ozone Corp. in Stamford, Connecticut* using standard analytical methods de-
scribed in Table 17.  The modified Liebig method was used for all cyanide
determinations.
*Presently located in West Caldwell, New Jersey
                                     15

-------
                                   SECTION 6

                      OPERATION UNDER OPTIMUM CONDITIONS


      Optimum operating conditions were determined by studying the effect of
 process parameters,  as described in Sections 5 and 7.

      The optimum process parameters for the Sealectro Plating Waste Treat-
 ment Plant were found to be as follows:

 a)    Ozone dosage:   1 to 1.5 mole 0 /mole CN~ or 1.85 to 2.8 mg/1 0_ per mg/1
      QT.                           •*                               3

 b)    pH of cyanide waste:   7.0 to 9.5 before ozone treatment.

 c)    pH of treated final effluent:   9.0 to 9.5 in the  settling tank.

 d)    Ambient temperature any time during the year (14  to 20°C).

      The plant  was operated under these optimum conditions  for approximately
 two  weeks,  16 hours  per day,  at  combined waste flows  approximately 1.5  times
 that of design  capacity.  Typical data obtained at the extremes  of the  opti-
 mum  operating range  are shown in Table 3.

      The data in Table 4 indicate that an ozone dosage of only one mole of
 ozone per mole  of cyanide ion suffices to reduce the cyanide concentration to
 0.08 mg/1 in the effluent from the  ozone contact tank  (Effluent  III).   How-
 ever, contamination  by CN"in  the acid  waste  stream caused the  final discharge
 (Effluent IV) to contain 0.64 mg/1  cyanide.  Metal ion concentrations in the
 final treated effluent (Effluent IV) were  as follows  (mg/1):

          Copper	   1.7
          Silver	<0.1 (the  limit  of detection  for the  analytical
                                   method  used.)
          Nickel	   0.4

     The cyanate  concentration was 6.0 mg/1.  More complete  removal of  cya-
nate can be achieved with a higher dosage  of ozone, but cyanate control  is
not necessary to meet  local or Federal standards.

     These results are remarkably good considering  the  fact  that  the acid
waste contained 0.2 to 0.8 mg/1  cyanide when it was not supposed  to contain
any.   During the treatment sequence the acid wastewater is combined with the
ozone treated cyanide waste, the pH adjusted and the combined wastewater fed
into the settling tank and then discharged as final treated  effluent  (IV).

                                     16

-------
                                TABLE 3
                   OZONE TREATMENT OF PLATING WASTE2
                     TYPICAL OPERATING CONDITIONS
 Experiment

CN~ @ Port I
Ozone
(0.*)/(CN ) "**",
(03-Cu)/(CN~r
Cyanide Waste
(mg/1)
>, Cmg/1)
Wr
1
Input
15.2s. o,
29. 7/ '-' "
1.05
1.03

12. 9 > °
35.2
1.48
1.47
pH at Sample Ports0
CN Tank (I)
Reactor (III)
Clarifier (IV)

Cu
Ag
Ni

CN-
CN Removal

CN
CNO~
Cu
Ag
Ni

Metal Input in Combined
(mg/1)
(mg/1)
(mg/1)
7.0-8.0
7.0
9.5
Inflow (I + II)
4.24.
NFd
0.84
9.5
7.0-8.0
9.0

7.50
0.71
NF
Effluent from Ozone Treatment Tank fill)6
(mg/1)
Final Effluent
(mg/1)
(mg/1)
(mg/1)
(mg/1)
(mg/1)
0.08
99.5
(IV)f
0.64
6.0
1.7
g
0.4
0.08
99.4

0.85
4.2
2.2
g
0.7
d

e

f

g
Plating Waste:  Na3Cu(CN)4  at  34  1/min (9  gpm)  flow,  1.33X design
flow of 25.5  1/min  (6.75 gpm).  Acidic waste  flow:   94.5  1/min
(25 gpm) or 1.5 X design flow  of  60  1/min  (16 gpm).

(°3'Cu.^/(CN ) is the mole ratio after  accounting  for  oxidation of Cu"1
to Cu

Roman numerals refer to sampling  ports indicated  on Figure 1.

NF - None found.

Ozone treated cyanide waste before mixing with  acid waste.

Metal values = total; includes soluble plus suspended.

Detected at limit of detection of procedure used, 0.1 mg/1  for Ag.
                                  17

-------
     Cyanide in the acid waste stream has two undesirable effects.  It
increases the cyanide concentration in the effluent.  That is the reason
why Effluent III contains only 0.08 mg/1 cyanide while Effluent IV con-
tains 0.64 mg/1.  The second undesirable effect is that the cyanide pre-
sent in the settling tank may increase the solubility of metal ions by
complexing.  The system is so designed that the acid waste cannot be ozo-
nated.  Correction lies in improved maintenance and housekeeping.  Never-
theless, even with this minor problem, the Sealectro Plating Waste Treat-
ment Plant meets all local and EPA code requirements, as discussed in
Section 1.  Cyanide concentration was consistently reduced to 0.08 mg/1
in the ozone reactor effluent.

     Another key point worth mentioning is that repeated measurements,
using a Mast ozone meter, showed no significant ozone emission in the vent
gases from the ozone contact tank.  All measurements showed an ozone con-
centration of 0.05 ppm or less.

     The sludge from the settling tank was collected during the two weeks
of optimum conditions operation.  A very small amount of sludge formed
during that time (approximately 1 to 2 kg on a dry basis).  It was readily
settleable and filterable.  A sample was dried at 130°C and analyzed for
metal content, using atomic absorption spectroscopy.  The results are as
follows: copper 18%, silver 0.1%, nickel 18%, iron 0.6%, lead 0.8%,
tin 24%, all by weight.
                                    18

-------
                                 SECTION 7

                        STUDY OF PROCESS PARAMETERS
     The effect of various process parameters on the plating waste treatment
was studied to establish optimum operating conditions.  The study was carried
out by temporarily upsetting the various parameters and recording their ef-
fect  without interrupting the operation of the treatment plant or of the
plating facility.  This approach permitted the normal production schedule for
the plating plant to be maintained.
                          *
     The study could not be made as detailed and thorough as would have been
preferred due to time and budget limitations.  An added limitation was the
initial operating difficulties with the new plating plant and the inexper-
ience of the operating personnel with the new equipment.

     The approach used for the study was discussed in detail in Section 5.
The quality of the final treated effluent was somewhat affected by low cya^
nide and metal concentrations in the acid waste as noted in Section 5 and 6.

     The results of the process parameter study are compiled in Tables 4, 5,
6 and 7.  The data in these tables include most of the information obtained
when the treatment plant was operated under upset operating conditions, with
less than stoichiometric amounts of ozone and with both a small excess and
with a large excess of ozone.  For ease in understanding, these data are also
presented in a summarized form in Tables 8, 9, 10 and 11 later in the report,
together with the following discussion of the various process parameters.

     The effect of ozone dosage or the ozone/cyanide mole ratio was studied
at several concentration levels of cyanide.  These studies showed that ozone
dosage is the most important process parameter.  The results are as follows:

a)   At a low cyanide concentration (to 20 mg/1) an 03/CN~mole ratio of 1:1
     is sufficient to reduce cyanide concentrations to below 0.1 mg/1, as
     indicated by the data in Table 8;

b)   At intermediate cyanide concentrations (20 to 40 mg/1) a mole ratio of
     2.0 ozone/cyanide is needed to reduce the cyanide concentration to
     <1 mg/1 and 3.6 to achieve <0.1 mg/1, as indicated by the data in
     Table 9.  The relationship for cyanate is less clear, but suggests that
     high 0,/CN~ratios (3.6) are also necessary for effective destruction;

c)   At higher concentrations (>50 mg/1) a mole ratio of 1.33 ozone/cyanide
     reduces the cyanide concentration to 0.52 mg/1, as indicated by the
     data in Table 10.  This ratio is inadequate for effective CNO"removal.

                                     19

-------
                                                                                                      T«bl« 4

                                                                           OZOm TMATMEHT OT P1ATCTC VAST! TOPER PTSCT OPE1ATOTC COHPITIOIIS*
FaraMUr DpMt
Acidic pi In Clarlflu
rum* DOM** V«rl«d
n
•lib Coaantntlon (2X)
OmoM CM,"**"
It
Input
OT (I) Oion. Mole Utlo
(»«/l) (»t/l) (Qa/a-)
2.1 43.6 11.4
IS. 7 «.« 1.5
1.2 23.8 12.2
10.3 50.1 2.7
17.5 50.1 1.6
27.0 217.2 4.4
31.5 254.3 4.4
3».0 243.7 3.5
pR >t Sovl* rort«k
(Or) luctor Cl.rlfUt
(I) (III) (TO
8.0 7.0 2.0-3.0
S.O 7.0 2.0-3.0
7.5 7.1 ll.»
S.O 7.0 9.0
8.0-9.0 7.0-8.0 9.0-10.0
13.5 12.9 13.1
9.5 7.8 S.5
1.6 7.0-8.0 6.5
Total Burr M>t*l Input
la Combined Inflow I «nd II
Cu A* Pb Rl r«
(n«/0
4. 54 0.10 XT 0.63 O.S1
5.27 0.11 IT ICT HT
3.42 0.42 W 1.33 0.56
S.01 0.10 IT MT XT
9.25 0.69 XT 4.69 W
,-m m n mm
10.36 0.12 XT 0.21 XT
15.99 0.03 »T »6.8 0.62
Oson* Kaactor
Sffluent (III)
U«/l) 	
0.08 3.5
4.1 14.0
0.2 ID
0.21 11.0
0.43 21.0
0.23 44.1
0.16 26.0
0.15 16.0
naal Effli»nt (IV)C
C^/l)
0.60 0.0 0.7 0.17 IT 0.4 1.7
0.71 0.0 4.6 0.23 XT 0.4 1.1
0.72 m 3.0 0.23 1.3 0.6 0.5
0.53 4.2 7.0 0.12 XT 2.1 IT
1.4 6.0 6.4 0.64 IT 3.6 CT
0.6* 7.2 «D ID m> TO XO
0.54 S.O 12.4 0.12 IT 0.3 HT
0.13 7.2 ID ID ID ID IT
•tUttns MM OU}Ca«a4) at 9 CFM flov. 1.3 tliaa dealfn flow of 6.75 CTM. Ih« acid mitt flow vai 25 GPM, 1.5 tlmei de«ljn flow of 16 CW. Th« otooc conemtratloB In Mlutloa nprunt* th.
aMBt of OIOIM f«d lato thtt T**ctor.
NJ
O
••OMB mania npraaaat aanpla  porta,  aa par Wgara I.

Tha a»tal anljala doaa not rapraaant aqalllbrlim opaTatlng condltlona.  Sufficient tlna probably
                                                                                                                not «llov»d for  th*  cl«rlfl«r to raach equlllbrlim condition!.
            •T -mol
            ID-not

-------
                                  TABLE 5

                     OZONE TREATMENT OF PLATING WASTE
                  LESS THAN STOICHIOMETRIC OZONE DOSAGE3

Experiment No.

CN- @ Port I
Ozone
Mole Ratio (0,/CN)

CN- (I)
Reactor (III)
Clarifier (IV)
Cyanide Waste Input
(mg/1) 71.0
(rag/1) 46.0
0.35
pH At Sample Ports
8.5
8.1
8.5
Metals in Combined Inflow (I) +
Cu
Ag
Pb
Ni
Sn

CN-
CNO"

CN"
CNO"
Cu
Ag
Pb
Ni
Sn

CNT (¥)
CNO" (%)
20.7
0.71
NFC
1.4
NF
Ozone Reactor Effluent (III)
12.1
48.0

78.0
50.5
0.35

8.6
8.1
9.5
(II) (mg/1)
21.0
0.43
1.1
NF
NF
(mg/1)
5.4
65.0

75.0
48.0
0.35

8.1
8.0
7.1

28.2
0.24
NF
NF
NF

12.8
25.0

75.0
48.0
0.35

9.4
9.1
6.6

26.6
NF
0.6
NF
NF

11.5
47.0
Final Effluent (IV! fme/11d
3.2' '
3.5
8.1
1.03
NF
1.41
NF
Percent Removal at (IV)
95.5
94.8
1.8
4.8
10.3
0.46
NF
NF
NF

97.6
93.7
4.2
0.0
22.4
0.11
NF
0.89
NF

94.4
100.0
4.6
0.0
11.9
0.17
NF
0.62
NF

93.9
100.0
    Cyanide Complex, Na3Cu(CN)4 plating work  at  34  1/min  (9  gpm)  flow,  1.33X
    design flow of 25.5  1/min  (6.75 gpm).  The acidic waste  flow  was 94.5
    mg/1  (25 gpm), 1.5 X design flow of 60 1/min (16 gpm).   The ozone con-
    centration represents the  amount of ozone fed into the reactor.

    Roman numerals represent sample ports as  per Figure 1.
    NF - None found.

    The metal analyses at IV should be considered only as an indication be-
    cause sufficient time probably was not allowed  for the clarifier to
    reach equilibrium.
                                     21

-------
                                                                  Table 6




                                        OZONE TREATMENT OF PLATING WASTE WITH SMALL EXCESS OF OZONE3
Input
CN- @ I Ozone Mole Ratio
(mg/1) (mg/1) (03/CN~)
15.2 29.7 1.05
63.0 173.1 1.33
38.0 129.8 1.84
37.5 194.8 2.81
36.3 194.8 2.91
29.0 194.8 3.64
pH at Sample Portsb
(CN~) (Reactor) Clarifier
(I) (III) (IV)
7.1-8.0 7.0 12.0
11.0 10.0 6.8
10.2 8.9 8.5
10.9 9.8 8.5
11.2 9.8 9.0
10.8 8.7 6.9
Reactor Effluent (III-)
CN~ CNO~ CN~
(mg/1) % Removal
0.52 42.5 99.2
0.23 10.6 99.1
0.35 8.9 99.1
0.21 7.2 99.4
0.08 0.0 99.7
Final Effluent (IV)
CN~ CNO~ CN~ CNO~
(mg/1) % Removal
0.64 6.0 96.6 60.5
0.90 8.4 98.6 86.7
0.60 6.3 98.4 83.4
0.9 4.4 97.6 88.3
0.75 0.5 97.9 98.6
0.31 0.0 98.9 100.0
to
                     aCyanide Comolex
                      Roman numerals represent sample ports as per Figure I.

-------
                                                                                                         TaM« 7



                                                                                    PIQUE TKEAlrlPIT OF PUTIKS WASTI WITH EXCISS OZJIIEa
to
u>
zntn


a5rT.yy Vffa TpJWT^
3«-4 141.1 2.0
M-* 141.J -3
31.0 141.1 .3
32.8 143.3 .4
32.S 143.3 .4
32-1 143.1 .4
12.0 14J.1 .4
31.5 143.3 .5
10.2 141.] .6
29. S 141.1 .6
11.0 6*. 4 .7
21.5 14X1 .7
6.5 64.4 .4
S.« 64.4 .1
3.3 64.4 .6
5-3 64.4 .6
.B .t s.,01. Port,"

fCB-1 (11 mactor [HI) Clirifler  ID ID
11.95 0.06 C.35 3.43 ft
31.99 0.35 IF IF IT
BD ID HO HO ID
BD ID BO 1C H>
8.86 0.13 BD 3.24 ID
BD ID BD BD ID
2.25 0.06 BF BF IT
7.30 0.37 ttr 0.37 ID
BD ID ^0 BD ID
12.60 0.39 ff jj 0.42 IF
9.07 0.21 HT 0.22 ID
39.70 0.31 1..47 0.49 IF
14.74 0.03 HF 0.56 BF
Ozon« leftctor
EffliMnt III (ma/11


0.82-0.66 ID ID ID ID ID BD
0. 22 12.0
0. (2 5.0 l.E IF IF 3.81 BF 1 0.34 BD
0.62-0.86 ID 1.5 0. 16 IF IF BF I 0. GO NO
0.64 ID 1.8 0.11 IF 0.57 BF
0.38 13.0
0.71 ID 6.9 IF BF SF F? | 0. 40 10.0
0.75 0.0 8.4 IF IF 4.86 BF 0.55 10.0
O.42 7.0 ID ID BD ID BD
0.72 0.0 1.5 0.16 BF IT BF
O.75 ID 1.1 0.11 BF IF BF
C.75 ID ID ID BD ID BD
0.04 ID 8.7 0.81 IF 0.29 BF
0.75 6.0 7.8 0.37 IF 0.68 BF
0.3 ID 2.7 0.11 IF 0.44 BF
0.3 KD 13.5 0. 37 BF IF BF
7.27 0.18 SI 0.42 IF j 0.5 ID 6.9 0.11 IF 0.73 BF
7.87 0.36 Nf 0.84 IF | 0.7 ID 7.3 0.26 BF 1.75 BF
0.54 16.0
0.52 16.0
0.60 ID
0.62 BD
0.02 BD
0.62 BD
0.08 BD
0.12 ID
0.3 ID
0.04 BD
        co.pl.,


      nu»«r*ls r*pr*nnt


HI * not d.tirmined


BF • not found
                                            ports u p«r

-------
                                                     TABLE 8


                                THE EFFECT OF OZONE DOSAGE AT LOW CONCENTRATIONS

                                                   OF CYANIDE*
to
Influent
Cyanide Ion
(mg/1)
2.1
5.3
6.5
12.9
13.0
15.2
Mole Ratio
(03/CN-)
11.37
6.62
5.39
1.48
2.69
1.05
pH at CD

8.0
12.6
10.1
7.5
7.7
9.5
Ozone Reactor
Effluent (III)
(CN- rag/1)
0.08
0.04
0.08
0.08
0.02
0.08
                         Cyanide is present  as Naj:u(CN)
                                                 •J     *

-------
in
                                                  TABLE 9
                        THE EFFECT OF OZONE DOSAGE ON  INTERMEDIATE CONCENTRATIONS
                                           OF COPPER CYANIDE3
                                                                      Ozone Reactor Effluent  (III)
Cyanide Ion Mole Ratio






a
b
(mg/1)
29.0
37.5
32.0
34.2
38.4
Cyanide
*m XT^~
pH at
(I)
(03/CN-)
3
2
2
2
2
is present as
» — . JA4..A.A^.A.J
.64
.81
.42
.26
.01
Na3Cu(CN)4

10
10
11
9
9


.8
.9
.9
.6
.5


Cone.
(CN-)
0.08
0.35
0.38
0.60
0.62


(mg/1)
(CNO-)
0.0
8.9
13.0
ND
ND


% Removal
(CN-)
99
99
98
98
98


.7
.1
.8
.2
.4


(CNO-)
100.
76.
59.
ND
ND


0
3
4




                                                  TABLE 10
                              THE EFFECT OF OZONE DOSAGE ON HIGH CONCENTRATIONS
                                             OF COPPER CYANIDE3
                                                                      Ozone Reactor Effluent (III)
Cyanide Ion
(mg/1)
63.0
75.0
Mole Ratio
(03/CN-)
1.33
0.35
pH at (I)

11.0
9.4
Cone.
(CN-)
0.52
11.5
(mg/1) % Removal
(CNO-)
42.5
47.0
(CN-)
99.2
84.6
(CNO~)
32.5
37.3
                Cyanide is present as Na_Cu(CN)^

-------
ISJ
                                                TABLE 11


                                 THE EFFECT OF CYANIDE CONCENTRATION
                              AT CONSTANT OZONE TO COPPER CYANIDE RATIOS
a
                                                                     Ozone Reactor Effluent  (HI)
             Cyanide Ion	Mole Ratio	pH at  (I)	Conc.(mg/l)	%  Removal
(mg/1)
37.5
75.0
12.9
63.0
13.0
32.0
34.2
(03/CN-)
0.35-0.5
0.35-0.5
1.3 -1.6
1.3 -1.6
2.3 -2.7
2.3 -2.7
2.3 -2.7

10.9
9.4
9.5
11.0
7.7
11.9
9.6
(CN-)
0.35
11.5
0.08
0.52
0.02
0.38
0.6
CCNO- )
8.9
47.0
4.2
42.5
ND
13.0
ND
CCN-)
99.1
84.6
99.4
99.2
	
98.8
98.2
(CNO-)
76.3
37.3
	
	
	
59.4
ND
             b Cyanide is present as Na,Cu(CN)4
               None detected

-------
      Insufficient experimentation was done at this level, which is well be-
      yond that encountered by Sealectro, to arrive at more specific conclu-
      sions such as the ozone dosage needed for complete CN~ removal
      «0.1 mg/1).

d)    The effect of cyanide concentration at three ozone/cyanide ratios is
      shown in Table 11.  These data again suggest that a larger dosage of
      ozone is needed to reach the same residual cyanide concentration
      (<1 mg/1) at higher influent cyanide concentrations.

      The pH of the cyanide waste prior to ozone treatment (Sample Port I)
was found not to be a critical variable in the range of 7.0.to 13.0,
as shown by data in Table 7.  It was observed that ozone treatment lowers
the pH by approximately one pH unit, as indicated by comparing the data in
Tables 4, 6 and 7, for Sample Ports I and III, i.e., before and after ozo-
nation.

      The pH of the treated effluent in the clarifier also is not critical,
as far as the cyanide and cyanate concentrations are concerned.  Acidic pH
in the settling tank leads to lower cyanate and cyanide concentrations
probably by accelerating decomposition of them as indicated by the data in
Table 4.  Surprisingly, the acidic pH did not seem to increase the total
copper and silver concentrations in the effluent (IV).  The explanation may
be that these metals are present as relatively  insoluble  oxides or the
times of these experimental runs were insufficient to establish equilibrium
in the settling tank (See Section 5).  Analyses are, however, total values
and it should be noted that the metal values presented in Tables 4 to 7
reflect both soluble and suspended (non-settled) metal in the effluent.

     An increase of ozone concentration from 1% to 2% in the ozone feed did
not produce a significant reduction in cyanide or cyanate concentration under
the test conditions, as indicated by the data in Tables 4 and 7.  This result
suggests that mass transfer of ozone is not the limiting parameter under the
conditions of this study.

     The reaction temperature was carefully recorded for all experiments but
variations did not produce an observable effect.  No effort was made to con-
trol the temperature.   The ambient wastewater temperature varied in the range
of 14 to 20 C during the test program.
                                     27

-------
                                 SECTION  8

                        TREATMENT OF SODIUM CYANIDE


     The ozone treatment of sodium cyanide was studied during a summer plant
shut-down.  The approach taken was as outlined in Section 5.  The results
summarized in Table  12 indicate that ozone treatment effectively destroys
sodium cyanide as well as the cyanate generated as an intermediate.  Complete
removal of cyanide and cyanate is possible if a sufficiently large ozone
dosage is used.  A mole ratio of 2.65 ozone/cyanide or higher removed at
least 97.6% of the cyanide.  However, a mole ratio of 4.3 ozone/cyanide was
needed to remove 44.8% of the cyanate generated and an 0 /CN"ratio of 14.0
was needed for 97% CNO~ removal.  The pH was again not critical based on re-
actions carried out at several pH's in the range of 7.7 to 10.5.  Thus, it
appears that ozonation of cyanide is more rapid than the ozonation and, pos-
sibly, the hydrolysis of cyanate.

     The main process parameters,  cyanide concentration, ozone/cyanide mole
ratios, and pH were varied through a very broad range to cover all areas of
interest.   Additional experiments  are still needed to refine the results.
                                     28

-------
                                                TABLE 12
                           OZONE TREATMENT OF SODIUM CYANIDE ON PLANT SCALE*
to
VD
                      Input
            Cyanide Ion   Mole Ratio
pH at Sample Ports
  I            III
 Ozone Reactor Effluent (III)
Conc.fmg/1)         %  Removal
(mg/1)
3.6
19.2
18.0
34.0
55.0
140.0
250.0
to
43
1.4
8
4
2
1
0
3/CN-)
.0
.0
.11
.30
.65
.04
.58

8
7
8
9
10
10
10

.2
.7
.2
.6
.1
.5
.4

5.
5.
5.
7.
8.
9.
9.

4
7
4
3
9
6
2
(CN-)
0.0
0.23
0.23
0.38
1.30
40.0
71.0
CCNO-)
0.0
0.6
5.3
30.0
56.0
71.0
209.0
(CN
100
98
98
98
97
71
71
~)
.0
.8
.7
.9
.6
.4
.6
(CNO-)
100.0
96.9
70.6
44.8
36.3
37.5
28.2
              Sodium Cyanide (NaCN)
              Roman numerals represent sample ports as per Figure 1

-------
                                   SECTION 9

                                  DISCUSSION
      This demonstration study program reconfirmed on a plant scale our ear-
 lier laboratory findings (6)  that ozone treatment of copper cyanide plating
 waste is effective,  economical,  safe and reliable.   The treatment of sodium
 cyanide is also effective.   It was studied briefly in order to establish
 relative ease of treatment  on a  plant scale.   The data in Tables  3 and 11  in-
 dicate that copper cyanide  reacts faster and  requires less ozone  than does
 sodium cyanide.   This  is consistent with earlier evidence that copper is a
 catalyst for cyanide ozonation.
      The Sealectro Plating Plant  is  a small  plating  facility.   It plates  ap-
 proximately 2.6m /hr  surface  area and has  an installed  DC  amperage  capacity
 of 1200  amps.   The wastewater discharge  from this plant is subject  to  the
 Westchester County Sewer Code and the EPA  standards  for small plating  instal-
 lations,  as discussed in detail in Section 3.  The Sealectro Plant  operates
 well  within those standards when  following the standard operating procedures
 with  the PCI ozone system.

      The new Sealectro Plating Plant  produces an average flow of 130 1/min
 (34 gpm)  wastewater consisting of 34  1/min (9 gpm) alkaline cyanide flow  and
 95  1/min (25 gpm)  acid waste  flow.  This is  an unusually high flow  for such
 a  small  operation.  The management believes  that the high  rinse water  flow as-
 sures the all important high  quality  plating at minimum cost.  Furthermore,
 the acid  flow should  contain  no cyanide, but it does contain cyanide in the
 range of 0.2 to  0.8 mg/1 from leaks and unidentified sources.

      The  above two problems,  namely excessive wastewater flow and cyanide in
 the acid  line, placed  a limitation on  this study.  Efforts were made by
 Sealectro Corp.  to resolve  them.  Definite improvements  were made,  but the
 problems were not  completely  resolved  during this study.  We expect that  with
 further experience  in  the plating shop these problems will be minimized and
 resolved.

     The demonstration study  produced valuable information concerning  the
process parameters  for plating waste treatment and the  safety of ozone treat-
ment, as discussed below.    It should be recognized that  the data obtained in
 this study are strictly true  for the ozone contactors used and for  ozone  con-
 tactors of very similar design.  Other type  of contactors such as multistage
diffusion systems, positive pressure injectors,  etc., may lead to somewhat
different results.  Key considerations should be the mass transfer  rate of
ozone and the concentration of cyanide being treated.


                                      30

-------
OZONE DOSAGE

     The ozone dosage, that is, the mole ratio of ozone to cyanide, is the
most important process parameter.  However, the ozone dosage required for
the complete destruction of cyanide is also-dependent on the cyanide concen-
tration.  A mole ratio of  1 to 1.5 mole ozone per mole of cyanide was found
to be sufficient for the complete destruction (CN~<0.1 mg/1) of copper cya-
nide when cyanide concentration was 20 mg/1 or less.  This requirement grad-
ually increases to 3.0 moles of ozone per mole of cyanide at cyanide concen-
trations of 75 mg/1.

     There are several possible explanations for the dependence of the mole
ratio on cyanide concentration, as follows:

a)   The mass transfer of  ozone from gas to water is the rate controlling
     step in the initial stages of the reaction.  The destruction of the
     last 4 to 5% cyanide  is reaction rate controlled (10).  To achieve com-
     plete cyanide destruction (0.1 mg/1 CN~ or less) at high initial cya-
     nide concentrations,  ozone must be fed into the system for a longer
     period of time under  slow, reaction rate controlled conditions.  How-
     ever, under these conditions more ozone may be consumed by competing
     side reactions such as oxidative destruction of cyanates to carbon di-
     oxide.

b)   The cyanide waste may also contain hard-to-decompose cyanide complexes
     such as iron complexes or slower reacting sodium cyanide.  These re-
     quire a higher mole ratio of ozone to lower the final level of cyanide
     to 0.1 mg/1 or below.  Although we have occasionally detected iron in
     the Sealectro plating waste, in most cases it was not present in sig-
     nificant amounts.  The waste was not analyzed for other cyanide salts
     or complexes.

c)   The final, reaction rate controlled part of the reaction may be slow
     because all the copper is removed by oxidation and precipitation as in-
     soluble copper oxide; thus,  no copper catalysis occurs.

     Most likely all three cases occur.  However, the Sealectro Plant nor-
mally treats a relatively  low concentration of cyanide where these problems
are not very important.  At higher cyanide concentration, the ozone dosage
might be minimized by using a multistage ozone contact tank with possible
uv irradiation in the final stage, if necessary.

pH OF CYANIDE WASTE

     The pH of cyanide waste before the ozone treatment is relatively unim-
portant in the range of 7  to 10.  Since the cyanide waste is normally dis-
charged from the plating plant in this pH range, no pH adjustment is neces-
sary prior to ozone treatment.  This finding represents a significant saving
in capital cost since it eliminates one complete pH control system and one
agitator.
                                     31

-------
 REACTION TEMPERATURE

      Reaction temperature did not have a significant effect  in the  normal
 ambient temperature range of 14 to 20°C,  which is  in agreement with previous
 observations (12).

 SLUDGE FROM THE  REACTION

      The sludge  from the reaction was  collected at the  bottom  of the clari-
 fier.   The sludge that  settled during  the process  parameter  study was discar-
 ded,  since there was no way  to assure  equilibrium  conditions in the settling
 tank.

      During the  optimum conditions experiments  the sludge was  collected.  How-
 ever,  only a small  amount formed  during  the  two weeks of operation.   The
 sludge was heavy, readily settleable,  and filterable.   The analysis of  its
 metal  content is noted  in Section 6.   The operation of  the settling tanks was
 not studied in depth due to  the shortness of the study  time.   The use of co-
 agulants and settling tubes  could be expected  to improve the settling sub-
 stantially and could result  in further improvements in  the effluent quality.

 RECYCLING OF TREATED EFFLUENT

     Recycling of treated effluent was outside  the scope of  the project and
 was not investigated due to  a  lack of  time.  However, it is  clear that  the ef-
 fluent could be  used as  cooling water  for the ozone generator  and for other
 equipment,  such  as  air  conditioning and other machinery.

     The recycling  of the effluent into the plating process  is  a real pos-
 sibility in the  Sealectro Plant under  the following conditions:

 a)   If cyanide  is  kept  out  of the acid waste flow.

 b)   If a slightly  larger ozone dosage is  used,  approximately  2  moles of ozone
     per mole  of cyanide,  to assure essentially  complete removal of all cya-
     nate  and  copper and, possibly, more  of the  other trace metals.

 c)   If  a  coagulant  is added or settling  tubes are  used in the  settling tank
     to  further  improve metal  removal.

     Naturally, prior to  embarking on  a recycling program it should be ascer-
tained that  there is no adverse effect on  plating quality.

     In conclusion,   the Sealectro demonstration project is believed  to have
achieved its major objectives  and  is presently discharging an environmentally
acceptable effluent.
                                      32

-------
                                SECTION 10

                              COST EVALUATION
     The Sealectro Plating Waste Treatment Plant was designed with the re-
quirements of a plant demonstration study in mind.  Consequently, the design
exceeds the normal requirements for an operating plant in several respects,
especially in ozone generating capacity, instrumentation and flexibility built
into the plant.  Naturally, these extras carry a price tag.  Therefore, the
cost data given here should be considered with the above in mind.

     To present the most accurate and useful cost evaluation, data are com-
piled for the Sealectro Plant as it was built, as well as for a new hypothe-
tical plant as it would be built as an optimized operating plant based on the
Sealectro experience.  The Sealectro data were based on 1973 prices while the
new plant data are based on 1975 prices.

     The Sealectro Plant proved by weeks of continuous (16 hr/day) operation
that it can treat the following plating waste, well above original design
values:

a)   Cyanide Waste:  34 1/min average, 57 1/min peak (9 gpm average, 15 gpm
     peak) for short periods, cyanide (CN~) concentration 
-------
                                 TABLE 13

                      CAPITAL COST OF OZONE TREATMENT

                                                       1975       1973
                                                     Optimum     Actual

Ozone Generator, PCI, G-20 with auxilliary Air
     Prep Unit PRE-23          20 Ib/day 0           $25,000    $  -
                               26 Ib/day 0^             -        26,000a

Ozone Detector - Auto Control - PCI                    2,700      2,500

Tanks                                                  3,000      3,900

pH Control System - Foxboro/PCI                        3,000      2,800

Installation                                           5,000     10,000

Central Control Panel                                   -           800

Building                 300 sq ft @ $25/ft^           7,500
                         360 sq ft § $22/ft             -         7,922C

Holding Tanks, pumps, auxilliaries (above ground)       5,000       -   d
                                   (underground)        -        12,691
                         TOTAL CAPITAL COST          $51,200    $66,613
a    The ozone generating capacity of this ozone generator is 30% higher
     than necessary to provide flexibility for the EPA study.

b    Although only one pH control loop is necessary, two loops were in-
     stalled to provide flexibility for the EPA study.

c    The cost of the building may vary depending on location and type of
     construction.

     The holding tanks at Sealectro were exceptionally expensive.   Due to
     space limitations they were installed underground in a high water
     table,  flood area.   Normally, above ground tanks would suffice.

-------
                                TABLE  14

                WEEKLY OPERATING COST  FOR OZONE TREATMENT
                                                         1975
                                                      Optimum

Labor:  caustic make-up, operate 5 hr/wk  8  $10/hr     $  50.00
                                 3 hr/wk  8  $16.67/hr
Maintenance:  maintenance, repair, housekeeping
                                 5 hr/wk 8 $7/hr
                                 7 hr/wk 8 $5.52/hr

Power        20 Ib 0 /day 8 11.5 kwh/lb 0  8 Sf/kwh
             10 Ib 03/day 8 11.5 kwh/lb 0^ 8 7*/kwh

Chemicals                   420 Ib NaOH/wk § 26
-------
                               TABLE 15

                            TREATMENT COSTS

                                      1975 Optimum          1973 Actual
                                        24 hr/day            16 hr/day

Capital Cost $                          51,200.00,            66,613.00,
     $/1000 gal                          1,045.70?            2,040.86°
     $/1000 1                              276.76               539.91

Total Operating Cost $/day                  50.34                55.50
     $71000 gal                              1.03                 1.70
     $/1000 1                                0.27                 0.45

Total Treatment Cost $/dayC                 63.99                73.26
     $/1000 gal                              1.31                 2.24
     $71000 1                                0.35                 0.59
     Due to the 16 hr/day operation at Sealectro, these costs are ap-
     proximately 1.5X higher than they would be for a 24 hr/day operation.

     These costs are capital cost/daily volume and not depreciated.

     These costs include capital equipment depreciated over 15 years (at
     250 day/yr) and operating costs.
                                   36

-------
                                TABLE 16

                        CYANIDE DESTRUCTION COSTS
Capital Cost
                                      1975 Optimum          1973 Actual
                                        24 hr/day            16 hr/daya
                                        45,000.00,            55,468.00V
            1                              918.58°            1,698.41?
     $71000 gal                          3,472.22°            6,420.00?.
                                        15,254.23^           28,182.55?
                                         6,933.74b           12,810.25b

Operating Cost

     $/day                                  18.50                15.09
     $71000 1                                0.38                 0.46
     $/1000 gal                              1.43                 1.75
     $/kg CN                                 6.27                 7.66
     $/lb CN                                 2.85                 3.48
                      c
Total CN Removal Costs

     $/daX                                  30.50                29.88
     $/1000 1                                0.62                 0.91
     $71000 gal                              2.35                 3.45
     $/kg CN                                10.34                15.18
     $/lb CN                                 4.70                 6.90
     Due to the 16 hr/day operation at Sealectro, these costs are ap-
     proximately 1.5X higher than they would be for a 24 hr/day operation,

     These costs are not depreciated.

     These costs include capital equipment depreciated over 15 years (at
     250 day/yr) and operating costs.
                                    37

-------
                                SECTION 11

                            ANALYTICAL METHODS
     Table 17 presents the references for the analytical procedures used
during the course of this project.  These are the methods commonly used in
the electroplating industry, although it must be recognized that only the
larger companies can be expected to have the equipment and trained personnel
necessary to carry out the analyses.  (It should also be noted that analy-
tical services., either in-house or purchased, were not included as a line
item in the cost assessment.)
                                    38

-------
CNO"


Cu



Ag

Ni

Pb

Sn
                                  TABLE 17

                             ANALYTICAL METHODS
Compound to
Be Analyzed

NaCN as CN~
Na Cu(CN)
as CN" 4
Method Used

Modified Liebig
Titration
Modified Liebig
Titration
Range of
Application
Cmg/1)
1-20
1-20
Limit of
Detection
(ing/l)
0.1
0.1
Source

a
a
    p-dimethylben-
    zalrhodanine as
    indicator

    Pyridine-            0.07-5
    Pyrazolone
    Colormetric

Selective Ion
    Electrode            1.0 -10.0

Modified Nessler
    Method               1.0 -10.0
Atomic Absorption
    Spectroscopy
    (A.A.S.)
                                   Sources
                                                           0.05
                                                           0.5
0.5
              c, d
0.2
0.1
0.3
0.5
20
0.2
0.1
0.3
0.5
20
f
f
f
f
f
  Dodge, Zabban § Serfass, Analytical Methods for the Determination of Cya-
  nides in Plating Wastes and in Effluents from Treatment Processes, Plating,
  39:  pp  267-273, 1952.

  Standard Methods for the Examination of Water and Wastewater, APHA:   AWWA:
  WPCF, 1965, pp. 448-457.

  Riseman, John,  Electrode Techniques for Measuring Cyanide in Wastewaters,
  American Laboratory,. Dec. 1972.
                                     39

-------
                            TABLE 17 (Continued)


                                   Sources

  Frant, M. S., J. Ross, J. Riseman, Electrode Indicator Technique for
  Measuring Low Levels of Cyanide, Orion Research, Inc., Cambridge, MA.

  Dodge, B. F., and W. Zabban, Analytical Methods for the Determination of Cya-
  nates in Plating Wastes and in Effluents from Treatment Processes, Plating,
  39: pp  381-384, 1952.

  Elwell, W. T. and J. A. F. Gidley, Atomic Absorption Spectrophotometry,
  2nd Edition, Bergman Press, N.Y.,  1966.

° Instruments used for analysis:  1.  Beckman Spectrograph Model DB-GT.
  2.  A.A.S. - Atomic Absorption Spectrophotometer made by Aztec, Inc.
  3.  Selective Ion Electrode, Model 407A, Orion Corp. (CN~) electrode 94-06A;
  Ref electrode 91-0100.
                                      40

-------
                                REFERENCES

 1.    Battelle Memorial Institute for U.S. Dept. of Interior, Federal Water
      Quality Administration:  A State-of-the-Art Review of Metal Finishing
      Waste Treatment, Water Pollution Control Research Series 12010 EIE,
      Nov, 1968.

 2.    Lancy, L. E., Economic Study of Metal Finishing Waste Treatment, at
      53rd Annual Convention, American Electroplaters Society, East Orange,
      NJ, June, 1966.

 3.    Mulcahy, E. W., Pollution by Metallurgical Trade Wastes.  A Study of
      Causes and Suggested Cures, Metal Finishing, I: 289, July, 1955.

 4.    Pinner, W. L., Progress Report of American Electroplaters Society Re-
      search Projects on Plating Room Waste, In:  Proced. 7th Industrial
      Waste Conference, Purdue Univ. Eng. Ser. No. 79, 1952. pp 518-540.

 5.    Bollyky, L. J., Removing Specific Contaminants from Water:  Cyanide,
      Environmental Engineers' Handbook, Liptak, B. G. (ed.), Chilton Book Co.
      Radnor, PA, 1974.  Vol. I, pp 1587-9.

 6.    Bollyky, L. J., Ozone Treatment of Cyanide and Plating Waste.  In:
      Proc. of the First Symposium of the International Ozone Institute,
      Washington, DC, International Ozone Institute, Syracuse, NY, Dec, 1973.

 7.    Ozone Counters Waste Cyanides Lethal Punch, Chem. Eng. (Mar, 1958).

 8.    Guillerd, J. and C.  Valin, Traitment par 1'Ozone, L'Eau, May, 1961.

 9.   Diaper, E. W.  J., Ozone Moves to the Fore, Water and Wastes Eng., pp 65-
      69, May, 1972.

 10.  Sondak, N. E.  and B,  F. Dodge, The Oxidation of Cyanide-Bearing Plating
     Wastes  by Ozone, Plating,  48:   173-180,  Fed, 1961;  pp 280-284,  Mar,
      •i- y o A •

 11.  Selm, R.  P., Ozone Oxidation of Aqueous  Cyanide Waste Solutions in
     Stirred Batch Reactors and Packed Towers,  Amer.  Chem. Soc.  Ozone Chem-
     istry and Technology,  Advances in Chemistry Series, #21, 1959.   pp 66-
      / / •

lib.  Mathieu,  G.  I.,  In:   Proc.  of the First  Symposium of the International
     Ozone Institute, Washington,  DC;  International Ozone Institute, Syra-
     cuse, NY,  Dec, 1973.   pp 533-550 (See also Ref.  10, 21).
                                      41

-------
 12.   Khandelwal,  K.  K.,  A.  J.  Barduhn and C.  S.  Grove,  Kinetics  of  Ozonation
      of Cyanides,  Amer.  Chem.  Soc.  Ozone Chemistry and  Technology.  Advances
      in Chemistry Series,  #21, 1959.   pp 78-86.

 13.   Walker,  C. A. and W.  Zabban, Plating,  40:  777-780,  1953.

 14.   Niegowski, S.,  Ind. Eng.  Chem.,  45:   632,  1953.

 15.   Tyler, R. G., W. Maske, M.  J.  Westing, and  W.  Mathews, Sewage  and  Ind.
      Wastes,  23:   1150-1153, 1951.

 16.   Neuwirth, F., Berg-u Huttenman,  Jahrb.,  81:   126-131,  1933.

 17.   Serota,  L.,  Cyanide Waste Treatment  Ozonation and  Electrolysis, Metal
      Finishing, 56:  71-74,  1958.

 18.   Kandzus, P.  F., and A. A. Mokina, Use  of Ozone for  Purifying Industrial
      Waste Waters, Tr., Vses.  Nauch.  -Issled. Inst. Vodosnabzh,  Kanaliz.,
      Gidrotekh. S-oruzhenii  Imzh. Gidrogol.,  20:   40-5,  1967  (Russ.); C.A.,
      71:  6388v,  1969.

.19.   Bischoff, Ch., Fine Purification of  Waste Water by  Ozone with  Low  Pol-
      lution Load,  Fortschr. Wasserchem.  Ihrer Grenzgeb., 9:   121-30, 1968
      (Ger.);  C.A., 70: 14237q, 1969.

 20.   Bahenski, V.  and Zika, Treating  Cyanide  Wastes by Oxidation with Ozone,
      Koroze Ochrana Mater.,  10 (1):   19-21, 1966;  C.A.,  65:   6907c, 1966.

 21.   Garrison, R.  G., C. E. Mauk, and H.  W. Prengle, Cyanide Disposal System,
      In:  Proc. of the First Symposium of the International Ozone Institute,
      Washington, DC, International  Ozone  Institute, Syracuse, NY, Dec,  1973.
                                     42

-------
                                    TECHNICAL REPORT DATA
                             (Please read Instructions on the reverse before completing)
  1. REPORT NO.
   EPA-600/2-77-104
                  3. RECIPIENT'S ACCESSION-NO.
 4. TITLE AND SUBTITLE
  Ozone  Treatment of Cyanide-Bearing Plating Waste
                  5. REPORT DATE
                   June 1977 issuing  date
                                                             6. PERFORMING ORGANIZATION CODE
 7. AUTHOR(S)

  L. Joseph Bollyky, PCI Ozone.,
                  8. PERFORMING ORGANIZATION REPORT NO.
 9. PERF
         WING ORGANIZATION NAME AND ADDRESS
  Sealectro  Corporation
  225 Hoyt St.
  Mamaroneck,  New York 10543
                   10. PROGRAM ELEMENT NO.
                     1BB610
                  11. CONTRACT/GRANT NO.


                     R 802335
 12. SPONSORING AGENCY NAME AND ADDRESS
  Industrial  Environmental Research Lab,
  Office of Research and Development
  U.S. Environmental Protection Agency
  Cincinnati,  0-hio 45268
- Cin., OH
13. TYPE OF REPORT AND PERIOD COVERED
  Final
                  14. SPONSORING AGENCY CODE


                     EPA/600/12
 15. SUPPLEMENTARY NOTES
       The use  of ozone for CN destruction in the metal  finishing -industry has long
  been recognized as a technically  attractive alternative to chlorine  oxidation.  High
  capital cost  has,  in earlier years,  prevented its  implementation.

       This report documents a full scale installation in which it was demonstrated
  that alkaline cyanide waste could be effectively destroyed to levels well below
  1 ppm and with CN~ removal?? of  99%  at the levels  normally encountered,  thus satis-
  fying BATEA requirements.  Design features, problems and capital and operating cost
  data are presented and discussed.

       Selected aspects  of the cyanide-ozone reaction were also studied,  such as the
  effect of CN~/03 ratios, cyanide  source and concentration and the effectiveness of
  ozone for cyanate  elimination.
 7.
                                KEY WORDS AND DOCUMENT ANALYSIS
                  DESCRIPTORS
    Water pollution;  Abatement; Metal
    finishing; Electroplating; Waste treat-
    ment; Waste  water;  Oxidation;  Cyanides;
    Ozone
                                               b.lDENTIFIERS/OPEN ENDED TERMS
             uzonatlon;  metal
      oxides; Cyanide  removal
                                c.  COS AT I Field/Group
                                                 Unclassified
                                                         CLASS (This Report)
              iihl
EPA Form 2220-1 (9-73)
            ITY CLASS (Thispage)
       Unclaaalfj
                                21. NO. OF PAGES
                                   51
                                                                          22. PRICE
                                             43
                                                      U.S. GOVERNMENT PRINTING OFFICE: 1977-757-056M28 Region No. 5-ll

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