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 Source Water
                    69
     Acid
    Plant
   Slowdown
                    781
     Other
NFM Wastewater
                 Lime.
               NaOH
           Rainfall
Pressure
 Filter
 Molybdenum
*to Roaster
                               Pressure
                                Filter
                 .^.Selenium
                    to Storage
                                        x\
                                         782
Lime Pit
                                             67
                               Settling
                                 Ponds
                                        /\
                                          68
                Non-Scope
                  Streams
                               Discharge
                               to Creek
                        Figure V-'

     SAMPLING  SITES AT  PRIMARY MOLYBDENUM PLANT B
                              66
-------
Source Water
                   I  54  ]
  Reduction
   Furnace
  Scrubber
    Water
                             55
Discharge
to River
                       Figure  V-2

     SAMPLING  SITES AT PRIMARY MOLYBDENUM PLANT  C
                            67
-------
            PRIMARY MOLYBDENUM AND RHENIUM  SUBCATEGORY

                            SECTION VI

                SELECTION OF POLLUTANT  PARAMETERS


Section V of this supplement presented  data from primary molybde-
num and rhenium plant sampling visits and subsequent  chemical
analyses.  This section examines that data and discusses the
selection or exclusion of pollutants for potential  limitation.
The legal basis for the exclusion of toxic pollutants under
Paragraph 8(a) of the Settlement Agreement  is presented in
Section VI of the General Development Document.

Each pollutant selected for potential limitation is discussed  in
Section VI of the General Development Document.  That discussion
provides information concerning the nature of the pollutant
(i.e., whether it is a naturally occurring substance, processed
metal, or a manufactured compound); general physical  properties
and the form of the pollutant; toxic effects of the pollutant  in
humans and other animals; and behavior  of the pollutant in POTW
at the concentrations expected in industrial discharges.

The discussion that follows presents and briefly discusses the
selection of conventional and nonconventional pollutants for
effluent limitations.  Also described is the analysis that was
performed to select or exclude toxic pollutants for further
consideration for limitations and standards.  Pollutants will be
considered for limitation if they are present in concentrations
treatable by the technologies considered in this analysis.  The
treatable concentrations used for the toxic metals were the long-
term performance values achievable by chemical precipitation,
sedimentation, and filtration.  The treatable concentrations used
for the toxic organics were the long-term performance values
achievable by carbon adsorption (see Section VII of the General
Development Document - Combined Metals  Data Base).

CONVENTIONAL AND NONCONVENTIONAL POLLUTANT PARAMETERS

This study examined samples from the primary molybdenum and rhe-
nium subcategory for three conventional pollutant parameters (oil
and grease, total suspended solids, and pH)  and two nonconven-
tional pollutant parameters, ammonia and molybdenum.  Ammonia is
used extensively in the production of ammonium molybdate and is
expected to be present in the wastewaters associated with
ammonium molybdate production.  Treatable levels of molybdenum
are present in several streams in the subcategory.
                               69
-------
CONVENTIONAL AND NONCONVENTIONAL POLLUTANT  PARAMETERS  SELECTED

The conventional and nonconventional pollutants  or  pollutant
parameters selected for limitation in this  subcategory are:

     ammonia
     fluoride*
     molybdenum
     total suspended solids (TSS)
     pH

*The Agency is considering limiting the pollutant fluoride  in
 this subcategory and is soliciting comments from the  industry.
 Effluent limitations for fluoride would be based on treatment
 effectiveness concentrations of 19.9 mg/1  for the  monthly
 average and 35 mg/1 for the daily maximum.

Treatable levels of ammonia are known to be present in waste-
waters resulting from ammonium molybdate production.  A  theoreti-
cal concentration of 11,270 mg/1 was calculated  from mass balance
information supplied by one facility.  Ammonia is therefore
selected for limitation in this subcategory.  Molybdenum was
found in four of four raw waste samples ranging  from 1.69 mg/1 to
29 mg/1.  It is therefore selected for limitation.

Total suspended solids (TSS) concentrations ranging from less
than 1 to 87 mg/1 were observed in the sik  raw waste samples ana-
lyzed for this study.  Four of the concentrations are above the
2.6 mg/1 treatable concentration.  Most of  the specific  methods
used to remove toxic metals do so by converting  these metals to
precipitates, and these toxic-metal-containing precipitates
should not be discharged.  Meeting a limitation  on  total sus-
pended solids helps ensure that removal of  these precipitated
toxic metals has been effective.  For these reasons, total  sus-
pended solids are selected for limitation in this subcategory.

The six pH values observed during this study ranged from 0.72  to
9.6.  Three of the six values were equal to or less than 1.24.
Many deleterious effects are caused by extreme pH values or rapid
changes in pH.  Also, effective removal of  toxic metals  by pre-
cipitation requires careful control of pH.  Since pH control
within the desirable limits is readily attainable by available
treatment, pH is selected for limitation in this subcategory.

TOXIC POLLUTANTS

The frequency of occurrence of the toxic pollutants in the  raw
wastewater samples taken is presented in Table VI-1.  Table VI-1
is based on the raw wastewater data from streams 55 and  781 (see
Section V) and data contained in the confidential record.   These
data provide the basis for the categorization of specific pollu-
tants, as discussed below.  Treatment plant samples were not
considered in the frequency count.
                               70
-------
TOXIC POLLUTANTS NEVER DETECTED

The toxic pollutants listed below were not  detected  in  any raw
wastewater samples from this subcategory; therefore,  they  are  not
selected for consideration in establishing  limitations.

       1.  acenaphthene
       2.  acrolein
       3.  acrylonitrile
       4.  benzene
       5.  benzidene
       6.  carbon tetrachloride  (tetrachloromethane)
       7.  chlorobenzene
       8.  1,2,4-trichlorobenzene
       9.  hexachlorobenzene
      10.  1,2-dichloroethane
      11.  1,1,1-trichloroethane
      12.  hexachloroethane
      13.  1,1-dichloroethane
      14.  1,1,2-trichloroethane
      15.  1,1,2,2-tetrachloroethane
      16.  chloroethane
      17.  bis  (chloromethyl) ether  (DELETED)
      18.  bis  (2-chloroethyl) ether
      19.  2-chloroethyl vinyl ether (mixed)
      20.  2-chloronaphthalene
      21.  2,4,6-trichlorophenol
      22.  parachlorometa cresol
      23.  chloroform (trichloromethahe)
      24.  2-chlorophenol
      25.  1,2-dichlorobenzene
      26.  1,3-dichlorobenzene
      27.  1,4-dichlorobenzene
      28.  3,3'-dichlorobenzidine
      29.  1,1-dichloroethylene
      30.  1,2-trans-dichloroethylene
      31.  2,4-dichlorophenol
      32.  1,2-dichloropropane
      33.  1,2-dichloropropylene (1,3-dichloropropene)
      34.  2,4-dimethylphenol
      35.   2,4-dinitrotoluene
      36.   2,6-dinitrotoluene
      37.   1,2-diphenylhydrazine
      38.  ethylbenzene
      39.   fluoranthene
      40.   4-chlorophenyl phenyl ether
      41.   4-bromophenyl phenyl ether
      42.   bis(2-chloroisopropyl) ether
      43.   bis(2-choroethoxy)  methane
                              71
-------
45.   methyl chloride (chloromethane)
46.   methyl bromide (bromomethane)
47.   bromoform (tribromomethane)
48.   dichlorobromomethane
49.   trichlorofluoromethane (DELETED)
50.   dichlorodifluoromethane (DELETED)
51.   chlorodibromomethane
52.   hexachlorobutadiene
53.   hexachlorocyclopentadiene
54.   isophorone
55.   naphthalene
56.   nitrobenzene
57.   2-nitrophenol
58.   4-nitrophenol
59.   2,4-dinitrophenol
60.   4,6-dinitro-o-cresol
61.   N-nitrosodimethylamine
62.   N-nitrosodiphenylamine
63.   N-nitrosodi-n-propylamine
64.   pentachlorophenol
65.   phenol
66.   bis(2-ethylhexyl) phthalate
67.   butyl benzyl phthalate
68.   di-n-butyl phthalate
69.   di-n-octyl phthalate
70.   diethyl phthalate
71.   dimethyl phthalate
72.   benzo (a)anthracene (1,2-benzanthracene)
73.   benzo (a)pyrene (3,4-benzopyrene)
74.   3,4-benzofluoranthene
75.   benzo(k)fluoranthene  (11,12-benzofluoranthene)
76.   chrysene
77.   acenaphthylene
78.   anthracene
79.   benzo(ghi)perylene (1,11-benzoperylene)
80.   fluorene
81.   phenanthrene
82.   dibenzo (a,h)anthracene (1,2,5,6-dibenzanthracene)
83.   indeno (1,2,3-cd)pyrene (w,e,-o-phenylenepyrene)
84.   pyrene
85.   tetrachloroethylene
86.   toluene
87.   trichloroethylene
88.   vinyl chloride (chloroethylene)
89.   aldrin
90.   dieldrin
91.   chlordane (technical mixture and metabolites)
92.   4,4'-DDT
93.   4,4'-DDE(p,p'DDX)
                         72
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      94.  4,4'-DDD(p,p'TD£)
      95.  a-endosulfan-Alpha
      96.  b-endosulfan-Beta
      97.  endosulfan sulfate
      98.  endrin
      99.  endrin aldehyde
     100.  heptachlor
     101.  heptachlor epoxide
     102.  a-BHC-Alpha
     103.  b-BHC-Beta
     105.  g-BHC-Delta
     106.  PCB-1242  (Arochlor  1242)
     107.  PCB-1254  (Arochlor  1254)
     108.  PCB-1221  (Arochlor  1221)
     109.  PCB-1232  (Arochlor  1232)
     110.  PCB-1248  (Arochlor  1248)
     111.  PCB-1260  (Arochlor  1260)
     112.  PCB-1016  (Arochlor  1016)
     113.  toxaphene
     116.  asbestos
     129.  2,3, 7,8-tetrachlorodibenzo-p-dioxin  (TCDD)

TOXIC POLLUTANTS NEVER FOUND ABOVE THEIR ANALYTICAL  QUANTIFICA-
TION CONCENTRATION

The toxic pollutants listed below were never found above  their
analytical quantification concentration in any  raw wastewater
samples from this subcategory; therefore, they  are not  selected
for consideration in establishing limitations.

      44.  methylene chloride
     104.  gamma-BHC
     11 4.  antimony
     127.  thallium

TOXIC POLLUTANTS PRESENT BELOW CONCENTRATIONS ACHIEVABLE  BY
TREATMENT

The pollutants listed below are not selected for consideration in
establishing limitations because they were not  found in any raw
wastewater samples from this subcategory above  concentrations
considered achievable by existing or available  treatment  tech-
nologies.  These pollutants are discussed individually  following
the list.

     117.  beryllium
     118.  cadmium
     121.  cyanide
     123.  mercury
                               73
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Beryllium was detected above quantification  concentrations  in
three out of eight raw wastewater samples.   All  three values were
0.01 mg/1 which is significantly below  the concentration  consid-
ered achievable by identified treatment technology  (0.20  mg/1).
Beryllium is therefore not selected for limitation.

Cadmium was detected above quantification concentrations  in only
one out of eight raw wastewater samples.  The observed  concentra-
tion is 0.040 mg/1, which is below the  concentration considered
achievable by identified treatment technology (0.049 mg/1).
Cadmium is therefore not selected for limitation.

Cyanide was detected above quantification concentrations  in two
out of six raw wastewater samples.  The observed  concentrations
were 0.032 mg/1 and 0.033 mg/1.  Because both of  these  values  are
below the concentration considered achievable by  available  treat-
ment technology, 0.047 mg/1, cyanide is not  selected for
limitation.

Mercury was detected above quantification concentrations  in three
out of eight raw wastewater samples at  concentrations of  0.0088
mg/1, 0.0180 mg/1, and 0.0045 mg/1.  Because all  three  of these
values are below the concentration considered achievable  by
identified treatment technology, mercury is  not  selected  for
regulation.

TOXIC POLLUTANTS DETECTED IN A SMALL NUMBER  OF SOURCES

The following pollutant was not selected for limitation on  the
basis that it is detectable in the effluent  from  only a small
number of sources within the subcategory and it  is uniquely
related to only those sources.

     126.  silver

Although this pollutant was not selected for limitation in
establishing nationwide regulations, it may  be appropriate, on a
case-by-case basis, for the local permitter  to specify  effluent
limitations.

Silver was detected above the treatable level for silver  (0.07
mg/1) in only one out of eight raw waste samples.  The  observed
concentration is 0.18 mg/1.  The silver concentrations  observed
in the other seven samples analyzed were all below the  analytical
quantification level.  The Agency has no reason  to believe  that
treatable silver concentrations should be present in primary
molybdenum wastewaters and believes that this one value is  not
representative of the subcategory.  Silver is therefore not
selected for limitation.
                               74
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TOXIC  POLLUTANTS SELECTED  FOR  FURTHER CONSIDERATION IN ESTABLISH-
ING LIMITATIONS AND  STANDARDS

The toxic pollutants  listed  below  are selected  for  further con-
sideration  in  establishing limitations and  standards for this
subcategory.   The  toxic pollutants  selected for further consid-
eration  for  limitation are each  discussed following the list.

     115.  arsenic
     119.  chromium
     120.  copper
     122.  lead
     124.  nickel
     125.  selenium
     128.  zinc

Arsenic  was  detected  above the level  considered achievable by
identified treatment  technology  (0.34 mg/1) in  four out of eight
raw wastewater samples.  The treatable concentrations  observed
range  from 0.517 mg/1 to 12.4 mg/1.   Arsenic  may be present as an
impurity in  molybdenite ore  concentrates.   For  these reasons,
arsenic  is selected  for further  consideration for limitation.

Chromium was detected above  the  level considered achievable by
identified treatment  technology  (0.07 mg/1) in  four out of eight
raw wastewater samples.  The treatable concentrations  observed
range  from 3.08 mg/1  to 13.0 mg/1.  Because of  the  treatable
levels observed and because  chromium  may  be present as  an  impur-
ity in molybdenite ore concentrates,  chromium is selected  for
further  consideration for  limitation.

Copper was detected above  its treatability  level of 0.07 mg/1 in
three  of eight raw wastewater samples.  The treatable  concentra-
tions ranged in value from 0.54  mg/1  to 2.92  mg/1.   Copper is
therefore selected for further consideration  for limitation.

Lead was detected above the  treatability  level  of 0.08  mg/1 in
six out  of eight raw wastewater  samples.  The observed  values
ranged from  0.17 mg/1 to 9.5 mg/1.  Lead  is therefore  selected
for further  consideration  for limitation.

Nickel was detected above  the treatable level of 0.22 mg/1 in six
out of eight raw wastewater  samples.   The observed  values  ranged
from 0.66 mg/1 to 4.60 mg/1.  Nickel  is therefore selected for
further  consideration for  limitation.

Selenium was detected above  the  level considered achievable by
available technology in four out of eight raw wastewater samples.
The treatable concentrations observed ranged  from 0.786 to 61.2
mg/1.   Because of the treatable  concentrations  observed and
                               75
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because selenium may be present as an impurity in the molybdenite
ore concentrate, selenium is selected for further consideration
for limitation.

Zinc was detected above its treatable level of 0.23 mg/1  in  five
out of eight raw wastewater samples.  The observed values  ranged
from 0.51  to 8.2 mg/1.  Zinc is therefore selected for further
consideration for limitation.
                               76
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                                          80
-------
            PRIMARY MOLYBDENUM AND  RHENIUM SUBCATEGORY

                            SECTION  VII

                CONTROL AND TREATMENT TECHNOLOGIES


The preceding sections of this supplement  discussed  the  sources,
flows, and characteristics  of the wastewaters  generated  in  the
primary molybdenum and rhenium subcategory.  This section sum-
marizes the description of  these wastewaters and  indicates  the
level of treatment which is currently practiced for  each waste
stream.  Secondly, this section presents the control and treat-
ment technology options which were  examined by the Agency for
possible application to the primary molybdenum and rhenium
subcategory.

In addition, the Agency is  proposing to expand the applicability
of the promulgated metallurgical acid plants subcategory effluent
limitations and standards to include the molybdenum  sulfuric acid
plants.  This section will  also present the technology basis for
these promulgated limitations and standards for all  the  appropri-
ate regulatory levels.

CURRENT CONTROL AND TREATMENT PRACTICES

Control and treatment technologies  are discussed  in  general in
Section VII of the General Development Document.  The  basic prin-
ciples of these technologies and the applicability to  wastewater
similar to that found in this subcategory  are  presented  there.
This section presents a summary of  the control and treatment
technologies that are currently applied to each of the sources
generating wastewater in this subcategory.  As discussed in
Section V, wastewater associated with the  primary molybdenum and
rhenium subcategory is characterized by the presence of  the toxic
metal pollutants, ammonia, and suspended solids.  This analysis
is supported by the raw (untreated) wastewater data  in Section V.
Generally, these pollutants are present in each of the waste
streams at concentrations above treatability,  and these  waste
streams are commonly combined for treatment.   Construction of one
wastewater treatment system for combined treatment allows plants
to take advantage of economies of scale, and in some  instances,
to combine streams of differing alkalinity to  reduce treatment
chemical requirements.  Three plants in this subcategory cur-
rently have combined wastewater treatment  systems, consisting of
chemical precipitation and sedimentation.  One of these  three
plants also practices ammonia stripping.   Three options  have been
selected for consideration for BPT, BAT, NSPS, and pretreatment
standards in this subcategory, based on combined treatment of
these compatible waste streams.
                               81
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MOLYBDENUM SULFIDE LEACHING

One of the facilities surveyed reported the practice of leaching
and rinsing a portion of the molybdenite concentrate raw material
prior to roasting.  The concentrate is leached with nitric acid
and rinsed with water to remove excess alkali.  The leachate and
rinsewater are then discharged as a wastewater stream.  This
waste stream has an acidic pH, and treatable levels of toxic
metals and suspended solids.  The one facility which reported
this waste stream discharges it to an on-site evaporation pond
and contract hauls a portion of the contents of the pond period-
ically, thereby achieving zero discharge.

ROASTER S0£ SCRUBBER

Four facilities reported the use of caustic scrubbers to control
S02 emissions from molybdenum sulfide roasting operations.  The
blowdown from the caustic scrubber has an alkaline pH, and treat-
able concentrations of suspended solids and toxic metals.  All
four facilities reporting this waste stream achieve zero dis-
charge through evaporation ponds, lagoon disposal, or treatment
and reuse in other plant processes.  The specific practices
reported by the four facilities are:

     1.  Lime addition and sedimentation, recycle to other plant
         processes;
     2.  Neutralization, permanent lagoon disposal (no recycle);
     3.  Use as feedstock for fertilizer plant; and
     4.  Tailings pond (96 percent recycle).

MOLYBDIC OXIDE LEACHATE

Technical grade molybdic oxide may be leached with nitric acid,
aqueous ammonia, and water prior to dissolving and recrystalli-
zation to produce ammonium molybdate.  The spent leachate and
rinsewater contain treatable levels of toxic metals,  suspended
solids, and ammonia.  For the two plants generating this stream,
the reported treatment practices for this waste stream are as
follows:

     1.  Ammonia steam stripping, lime addition, and sedimenta-
         tion; and

     2.  Evaporation ponds and contract hauling.

HYDROGEN REDUCTION FURNACE SCRUBBER

Hydrogen gas from the reduction furnaces used to produce molybde-
num metal powder may be quenched or scrubbed with water prior to
reuse in the furnaces.  Treatable concentrations of toxic metals
                              82
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 are present  in  the  water  discharged  from the scrubbing system.
 Of the  two facilities  reporting  this wastewater stream,  one prac-
 tices extensive  recycle (>99  percent)  and the other practices no
 recycle.  Both  plants  are direct dischargers of this waste stream
 with no wastewater  treatment  practiced.

 DEPLETED RHENIUM SCRUBBING SOLUTION

 Rhenium is absorbed into  solution from molybdenite  roaster off-
 gases in a wet  scrubbing  system.   After  the  rhenium is recovered
 from solution,  the  barren scrubber liquor is discharged  as a
 wastewater stream.   Treatable  concentrations of toxic metals,
 particularly  selenium, are present in  this waste stream.   Both  of
 the facilities  reporting  this  waste  stream achieve  zero  dis-
 charge.  The  specific  practices  reported by  these facilities
 are:

     1.  Lime addition and sedimentation,  total reuse in  other
         plant  processes;  and

     2.  Evaporation ponds and contract  hauling.

 SULFURIC ACID PLANT SLOWDOWN

 When a  sulfuric  acid plant is  used to  control S02 emissions
 from molybdenite  roasting  operations,  a  wastewater  stream is
 generated consisting primarily of blowdown from water scrubbers
 which are used to clean the flue  gases upstream from the  cata-
 lytic converters  which convert S02 to  803.   This  wastewater
 stream  has an acidic pH and treatable  concentrations of  toxic
 metals  and suspended solids.   Of  the three facilities reporting
 this waste stream,  two reported no recycle and  one  reported 96
 percent recycle.  The reported wastewater  treatment practices for
 this stream are  as  follows:

     1.  Lime addition and  sedimentation (no recycle),

     2.  Sulfide  precipitation preliminary treatment using H2S
         addition,  followed by lime  addition and  sedimentation
         (no recycle), and

     3.  Contract hauling  after 96 percent recycle.

 CONTROL AND TREATMENT OPTIONS

 The Agency examined  three  control  and  treatment  technology alter-
natives that are  applicable to the primary molybdenum and rhenium
 subcategory.   The options  selected for evaluation represent a
 combination of in-process  flow reduction,  pretreatment technology
 applicable to individual waste streams,  and  end-of-pipe treatment
                               83
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technologies.  Following the discussion  of  these  treatment  alter-
natives, the technology basis of the promulgated  metallurgical
acid plants subcategory limitations and  standards will be
reviewed for the reader's reference.  EPA is proposing to expand
the applicability of the promulgated metallurgical acid  plants
regulation to include molybdenum sulfuric acid plants.   A
detailed discussion of the treatment technology selection for
each regulatory level can be found in the Metallurgical  Acid
Plants Subcategory Development Document  of  the Nonferrous Metals
Manufacturing Point Source Category, Phase  I.

OPTION A

The Option A treatment scheme consists of ammonia steam  stripping
preliminary treatment applied to molybdic oxide leachate waste-
water.  Preliminary treatment is followed by chemical precipita-
tion and sedimentation applied to the combined stream of steam  .
stripper effluent, molybdenum sulfide leaching, roaster  scrubber,
hydrogen reduction furnace scrubber wastewater, and depleted
rhenium scrubbing solution.  Chemical precipitation is used to
remove metals by the addition of lime followed by gravity sedi-
mentation.  Suspended solids are removed by this  process.

OPTION B

Option B for the primary molybdenum and  rhenium subcategory con-
sists of all treatment requirements of Option A (ammonia steam
stripping, chemical precipitation, and sedimentation) plus
control technologies to reduce the discharge of wastewater
volume.  Water recycle of hydrogen reduction furnace scrubber
liquor is the principal control mechanism for flow reduction.

OPTION C

Option C for the primary molybdenum and  rhenium subcategory con-
sists of all control and treatment requirements of Option B
(ammonia steam stripping, in-process flow reduction, chemical
precipitation, and sedimentation) plus multimedia filtration
technology added at the end of the Option B treatment scheme.
Multimedia filtration is used to remove  suspended solids,
including precipitates of metals, beyond the concentration
attainable by gravity sedimentation.  The filter  suggested  is of
the gravity, mixed media type, although  other forms of filters
such as rapid sand filters or pressure filters would perform as
well.  The addition of filters also provides consistent  removal
during periods in which there are rapiu  increases in flows  or
loadings of pollutants to the treatment  system.
                               84
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TREATMENT LEVELS FOR METALLURGICAL ACID PLANTS

BPT limitations for metallurgical acid plants are based on chemi-
cal precipitation and sedimentation treatment technology.  This
treatment scheme is shown in Figure IX-2.

BAT limitations for metallurgical acid plants are based on in-
process flow reduction, chemical precipitation and sedimentation,
sulfide precipitation and sedimentation, followed by multimedia
filtration for lead and zinc plants (see Figure X-4).  For copper
acid plants the BAT treatment technology is based on in-process
flow reduction, sulfide precipitation, pressure filtration,
chemical precipitation, sedimentation, and multimedia filtration
(see Figure X-5).  For molybdenum acid plants, the Agency is pro-
posing BAT limitations based on sulfide precipitation and pres-
sure filtration pretreatment, followed by chemical precipitation,
sedimentation, and multimedia filtration as presented in Figure
X-5.
                              85
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            PRIMARY MOLYBDENUM AND RHENIUM SUBCATEGORY

                           SECTION VIII

            COSTS, ENERGY, AND NONWATER QUALITY ASPECTS


This section presents a summary of compliance costs for the
primary molybdenum and rhenium subcategory and a description of
the treatment options and subcategory-specific assumptions used
to develop these estimates.  Together with the estimated pollu-
tant reduction performance presented in Sections IX, X, XI, and
XII of this supplement, these cost estimates provide a basis for
evaluating each regulatory option.  These cost estimates are also
used in determining the probable economic impact of regulation on
the subcategory at different pollutant discharge levels.  In
addition, this section addresses nonwater quality environmental
impacts of wastewater treatment and control alternatives, includ-
ing air pollution, solid wastes, and energy requirements, which
are specific to the primary molybdenum and rhenium subcategory.

TREATMENT OPTIONS FOR EXISTING SOURCES

As discussed in Section VII, three treatment options have been
developed for existing primary molybdenum and rhenium sources.
The treatment schemes for each option are summarized below and
schematically presented in Figures X-1 through X-3.  The regula-
tory treatment technologies for metallurgical acid plants were
discussed at the end of Section VII of this document.  The treat-
ment schemes for the regulatory levels are presented in Figures
IX-2, X-4, and X-5.

OPTION A

Option A consists of ammonia steam stripping preliminary treat-
ment and chemical precipitation and sedimentation end-of-pipe
technology.

OPTION B

Option B consists of in-process flow, reduction measures, ammonia
steam stripping preliminary treatment, and chemical precipitation
and sedimentation end-of-pipe technology.  The in-process flow
reduction measure consists of the recycle of hydrogen reduction
furnace scrubber water through holding tanks.

OPTION C

Option C requires the in-process flow reduction measures of
Option B, ammonia steam stripping preliminary treatment, and
end-of-pipe treatment technology consisting of chemical precipi-
tation, sedimentation,  and multimedia filtration.


                              87
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COST METHODOLOGY

A detailed discussion of  the methodology  used  to  develop  the
compliance costs is presented in Section  VIII  of  the  General
Development Document.  Plant-by-plant  compliance  costs  have been
estimated for the nonferrous metals manufacturing category and
are documented  in detail  in the administrative record supporting
this regulation.  The costs developed  for the  proposed  regulation
are presented in Table VIII-1.  The estimated  costs for metallur-
gical acid plants associated with primary molybdenum  operations
are presented in Table VIII-2.

Each of the general assumptions used to develop compliance costs
is presented in Section VIII of the General Development Document.
Each subcategory also contains a unique set of waste  streams
requiring certain subcategory-specific assumptions to develop
compliance costs.  The major assumptions  specific to  the  primary
molybdenum and rhenium subcategory are discussed  briefly  below.

     (1)  The acid plant blowdown waste stream  is found in two
          of the four plants belonging to this  subcategory and
          represents the only nonferrous  metals phase II  waste
          stream present.  The production normalized  regulatory
          flows developed under the phase I analysis  were used,
          although the raw waste characteristics  derived  from
          phase II sampling data were used as  the basis for cost
          estimation.

     (2)  Costs for the removal of molybdenum  are included in
          the treatment system costs.  Molybdenum treatment
          effectiveness concentrations are estimated  to be 1.41
          and 0.94 mg/1 for lime and settle and lime, settle and
          filter, respectively.

     (3)  Costs for plants having total flows  of  less than 100
          1/hr were based on the general  guidelines established
          for low flows.  These are discussed  in  Section  VIII of
          the General Development Document.

NONWATER QUALITY ASPECTS

A general discussion of the nonwater quality aspects  of the con-
trol and treatment options considered for the nonferrous  metals
category is contained in Section VIII of  the General  Development
Document.  Nonwater quality impacts for molybdenum sulfuric acid
plants are incorporated inLu the impacts  attributed to  the pri-
mary molybdenum and rhenium subcategory.   These impacts,  includ-
ing energy requirements, solid waste, and  air  pollution are
discussed below.
                                88
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ENERGY REQUIREMENTS

The methodology used  for determining  the  energy  requirements  for
the various options is discussed  in Section VIII of  the  General
Development Document.  Energy  requirements for Option  A  are  esti-
mated at 580,000 kWh/yr.  Option  B energy requirements decrease
over those for Option A because less  water is being  treated,  thus
saving energy costs for lime and  settle treatment.   Option C,
which includes filtration,  is  estimated to increase  energy con-
sumption over Option  B by approximately 1 percent.   Further,  the
total energy requirement for Option C is  approximately 1  percent
of the estimated total plant energy usage.  It is  therefore
concluded that the energy requirements of the treatment  options
considered will have no significant impact on total  plant energy
consumption.

SOLID WASTE

Sludges associated with the primary molybdenum and rhenium
subcategory will necessarily contain  quantities  of toxic  metal
pollutants.  Wastes generated  by  primary  smelters  and  refiners
are currently exempt  from regulation  by Act of Congress  (Resource
Conservation and Recovery Act  (RCRA),  Section 3001(b)),  as
interpreted by EPA.  Consequently, sludges generated from
treating primary molybdenum and rhenium wastewater,  including
metallurgical acid plants wastewater, are not presently  subject
to regulation as hazardous wastes.

The technology basis  for the metallurgical acid  plants includes
sulfide precipitation for the  control of  various  toxic metals.
The Agency believes sludge generated  through sulfide precipita-
tion (and sedimentation or pressure filtration)  will be  classi-
fied as hazardous under RCRA.  The costs  of hazardous  waste
disposal were considered in the economic  analysis  for  this
subcategory (in spite of the current  statutory and regulation
exemption)  because sulfide will not form metal hydroxides that
resist leaching.  The costs of hazardous  waste disposal were
determined to be economically  achievable.  However,  lime  sludges
are not expected to be hazardous.  This judgement  is based on the
results of Extraction Procedure (EP)  toxicity tests  performed on
similar sludges (toxic metal-bearing  sludges) generated by other
industries such as the iron and steel industry.  A small  amount
of excess lime was added during treatment, and the sludges subse-
quently generated passed the toxicity test.  See CFR §261.24.
Thus,  the Agency believes that the wastewater sludges  will simi-
larly not be EP toxic if the recommended  technology  is applied.

If these wastes should be identified or are listed as  hazardous,
they will come within the scope of RCRA's "cradle to grave"
hazardous waste management program, requiring regulation  from the
                                89
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point of generation to point of final disposition.  EPA's gener-
ator standards would require generators of hazardous nonferrous
metals manufacturing wastes to meet containerization, labeling,
recordkeeping, and reporting requirements; if plants dispose of
hazardous wastes off-site, they would have to prepare a manifest
which would track the movement of the wastes from the generator's
premises to a permitted off-site treatment, storage, or disposal
facility.  See 40 CFR 262.20, 45 FR 33142 (May 19, 1980), as
amended at 45 FR 86973 (December 31, 1980).  The transporter
regulations require transporters of hazardous wastes to comply
with the manifest system to assure that the wastes are delivered
to a permitted facility.  See 40 CFR 263.20, 45 FR 33151  (May 19,
1980), as amended at 45 FR 86973 (December 31, 1980).  Finally,
RCRA regulations establish standards for hazardous waste treat-
ment, storage, and disposal facilities allowed to receive such
wastes.  See 40 CFR Part 464, 46 FR 2802 (January 12, 1981), and
47 FR 32274 (July 26, 1982).

Even if these wastes are not identified as hazardous, they still
must be disposed of in compliance with the Subtitle D open dump-
ing standards, implementing Section 4004 of RCRA.  See 44 FR
53438 (September 13, 1979).  The Agency has calculated as part of
the costs for wastewater treatment the cost of hauling and dis-
posing of these wastes.  For more details, see Section VIII of
the general development document.

It is estimated that 1,052 kkg/yr of sludge will be generated as
a result of these proposed regulations for the primary molybdenum
and rhenium subcategory.

AIR POLLUTION

There is no reason to believe that any substantial air pollution
problems will result from implementation of ammonia steam strip-
ping, chemical precipitation, sedimentation, sulfide precipita-
tion, and multimedia filtration.  Ammonia steam stripping yields
an aqueous ammonia product stream.  The other technologies trans-
fer pollutants to solid waste and are not likely to transfer
pollutants to air.
                               90
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                           Table VIII-1

          COST OF COMPLIANCE FOR THE PRIMARY MOLYBDENUM
                     AND RHENIUM SUBCATEGORY
                        DIRECT DISCHARGERS
Compliance costs for this subcategory cannot be presented here
because the data on which they are based have been claimed to be
confidential.
                              91
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                           Table VIII-2

         COST OF COMPLIANCE FOR METALLURGICAL ACID PLANTS
          ASSOCIATED WITH PRIMARY MOLYBDENUM OPERATIONS
                        DIRECT DISCHARGERS
Compliance costs for this subcategory cannot be presented here
because the data on which they are based have been claimed to be
confidential.
                              92
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            PRIMARY MOLYBDENUM AND  RHENIUM SUBCATEGORY

                            SECTION IX

     BEST PRACTICABLE CONTROL TECHNOLOGY  CURRENTLY  AVAILABLE


This section defines the effluent characteristics attainable
through the application of best  practicable control technology
currently available (BPT), Section  301(b)(1)(A).  BPT  reflects
the existing performance by plants  of various  sizes, ages,  and
manufacturing processes within the  primary molybdenum  and  rhenium
subcategory, as well as the established performance of the recom-
mended BPT systems.  Particular  consideration  is given to  the
treatment already in place at existing plants.

The factors considered in identifying BPT include the  total cost
of applying the technology in relation to the  effluent reduction
benefits from such application,  the age of equipment and  facili-
ties involved, the manufacturing processes  used, nonwater  quality
environmental impacts (including energy requirements),  and other
factors the Administrator considers  appropriate.  In general,  the
BPT level represents the average of the existing performances of
plants of various ages, sizes, processes,  or other  common  charac-
teristics.  Where existing performance is uniformly inadequate,
BPT may be transferred from a different subcategory or category.
Limitations based on transfer of technology are supported  by a
rationale concluding that the technology  is  indeed  transferable,
and a reasonable prediction that it will  be capable of achieving
the prescribed effluent limits (see Tanner's Council of America
v. Train. 540 F.2d 1188 (4th Cir. 1176)).BPT focuses on
end-of-pipe treatment rather than process  changes or internal
controls, except where such practices are common industry
practice.

TECHNICAL APPROACH TO BPT

The Agency studied the nonferrous metals  category to identify the
processes used,  the wastewaters  generated,  and the  treatment
processes installed.  Information was collected from the category
using data collection portfolios, and specific plants  were sam-
pled and the wastewaters analyzed.   In making technical assess-
ments of data, reviewing manufacturing processes, and  assessing
wastewater treatment technology options,  both indirect and  direct
dischargers have been considered as  a single group.  An examina-
tion of plants and processes did not, indicate any process  differ-
ences based on the type of discharge, whether  it be direct or
indirect.
                                93
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As explained in Section IV, the primary molybdenum and rhenium
subcategory has been subdivided into six potential wastewater
sources.  Since the water use, discharge rates, and pollutant
characteristics of each of these wastewaters is potentially
unique, effluent limitations will be developed for each of the
six subdivisions.

For each of the subdivisions, a specific approach was followed
for the development of BPT mass limitations.  The first require-
ment to calculate these limitations is to account for production
and flow variability from plant to plant.  Therefore, a unit of
production or production normalizing parameter (PNP) was deter-
mined for each waste stream which could then be related to the
flow from the process to determine a production normalized flow.
Selection of the PNP for each process element is discussed in
Section IV.  Each plant within the subcategory was then analyzed
to determine (1) which subdivisions were present, (2) the specif-
ic flow rates generated for each subdivision, and (3) the specif-
ic production normalized flows for each subdivision.  This analy-
sis is discussed in detail in Section V.  Nonprocess wastewaters
such as rainfall runoff and noncontact cooling water are not
considered in the analysis.

Production normalized flows for each subdivision were then ana-
lyzed to determine the flow to be used as part of the basis for
BPT mass limitations.  The selected flow (sometimes referred to
as the BPT regulatory flow or BPT discharge rate) reflects the
water use controls which are common practices within the cate-
gory.  The BPT regulatory flow is based on the average of all
applicable data.  Plants with normalized flows above the average
may have to implement some method of flow reduction to achieve
the BPT limitations.

The second requirement to calculate mass limitations is the set
of concentrations that are achievable by application of the BPT
level of treatment technology.  Section VII discusses the various
control and treatment technologies which are currently in place
for each wastewater source.  In most cases, the current control
and treatment technologies consist of chemical precipitation and
sedimentation (lime and settle technology) and a combination of
reuse and recycle to reduce flow.  Ammonia steam stripping is
applied to streams with treatable concentrations of ammonia.

Using these regulatory flows and the achievable concentrations,
the next step is to calculate mass loadings for each wastewater
source or subdivision.  This calculation was made on a stream-
by-stream basis, primarily because plants in this subcategory may
perform one or more of the operations in various combinations.
The mass loadings (milligrams of pollutant per metric ton of
production - mg/kkg) were calculated by multiplying the BPT
regulatory flow  (1/kkg) by the concentration achievable by the
                              94
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BPT level of treatment technology  (mg/1) for each pollutant
parameter to be limited under BPT.  These mass loadings are
published in the Federal Register  and in CFR Part 400 as the
effluent limitations guidelines.

The mass loadings which are allowed under BPT for each plant will
be the sum of the individual mass  loadings for the various waste-
water sources which are found at particular plants.  Accordingly,
all the wastewater generated within a plant may be combined for
treatment in a single or common treatment system, but the efflu-
ent limitations for these combined wastewaters are based on the
various wastewater sources which actually contribute to the com-
bined flow.  This method accounts  for the variety of combinations
of wastewater sources and production processes which may be found
at primary molybdenum and rhenium  plants.

The Agency usually establishes wastewater limitations in terms of
mass rather than concentration.  This approach prevents the use
of dilution as a treatment method  (except for controlling pH).
The production normalized wastewater flow (1/kkg) is a link
between the production operations  and the effluent limitations.
The pollutant discharge attributable to each operation can be
calculated from the normalized flow and effluent concentration
achievable by the treatment technology and summed to derive an
appropriate limitation for each plant.

INDUSTRY COST AND POLLUTANT REMOVAL ESTIMATES

In balancing costs in relation to pollutant removal benefits, EPA
considers the volume and nature of existing discharges, the vol-
ume and nature of discharges expected after application of BPT,
the general environmental effects of the pollutants, and the cost
and economic impacts of the required pollution control level.
The Act does not require or permit consideration of water quality
problems attributable to particular point sources or industries,
or water quality improvements in particular water quality bodies.
Accordingly, water quality considerations were not the basis for
selecting the proposed BPT.  See Weyerhaeuser Company v. Costle,
590 F.2d 1011  (D.C. Cir. 1978).

The methodology for calculating pollutant removal estimates and
plant compliance costs is discussed in Section X.  Tables X-2 and
X-3 show the estimated pollutant removal estimates for each
treatment option for direct dischargers.  Compliance costs for
each option are presented in Table X-4 and X-5.

BPT OPTION SELECTION

The technology basis for the proposed BPT limitations is chemi-
cal precipitation and sedimentation technology to remove metals
                              95
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and solids from combined wastewaters and to control pH,  and
ammonia steam stripping preliminary treatment.  These  technolo-
gies are already in-place at one of the two dischargers  in the
subcategory.  The other two direct dischargers  in the  subcategory
discharge only metallurgical acid plant blowdown.  The BPT
limitations for these plants are discussed below.  The best
practicable technology is presented in Figure IX-1.  The BPT
treatment is equivalent to Option A described in Section VII.

Ammonia steam stripping is demonstrated at seven facilities in
the nonferrous metals manufacturing category.   These facilities
are treating ammonia bearing wastewaters associated with the
production of primary tungsten, primary columbium and  tantalum,
primary molybdenum, secondary tungsten and cobalt, secondary
molybdenum and vanadium, and primary zirconium  and hafnium.  EPA
believes that performance data from the iron and steel manufac-
turing category provide a valid measure of this technology's
performance on nonferrous metals manufacturing  category waste-
water because raw wastewater concentrations of  ammonia are of the
same order of magnitude in the respective raw wastewater
matrices.

Chemical analysis data were collected of raw waste (treatment
influent) and treated waste (treatment effluent) from  one coke
plant of the iron and steel manufacturing category.  A contractor
for EPA, using EPA sampling and chemical analysis protocols,
collected six paired samples in a two-month period.  These data
are the data base for determining the effectiveness of ammonia
steam stripping technology and are contained within the public
record supporting this document.  Ammonia treatment at this coke
plant consisted of two steam stripping columns  in series with.
steam injected countercurrently to the flow of  the wastewater.  A
lime reactor for pH adjustment separated the two stripping
columns.

The Agency has verified the proposed steam stripping performance
values using steam stripping data collected at  a zirconium-
hafnium plant, which has raw ammonia levels as high as any in the
nonferrous metals manufacturing category.  Data collected by the
plant represent almost two years of daily operations,  and support
the long-term mean used to establish treatment  effectiveness.

Implementation of the proposed BPT limitations will remove annu-
ally an estimated 73,631 kg of toxic metals, 1,049 kg  of molyb-
denum, 62,813 kg of ammonia, and 51,529 kg of TSS over estimated
current discharge.  While both discharging plants have the equip-
ment" in-place to comply with BPT, we do not believe that the
plants are currently achieving the BPT mass limitations.  The
estimated capital and annual cost for achieving the proposed BPT
cannot be presented here because the data on which they are based
have been claimed to be confidential.
                                96
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More  stringent  technology  options  were  not  selected  for BPT since
they  require  in-process  changes  or end-of-pipe  technologies less
widely practiced  in  the  subcategory,  and, therefore,  are more
appropriately considered under BAT.

We are expanding  the applicability of the existing BPT require-
ments for  the metallurgical  acid plants subcategory  to include
acid  plants associated with  primary molybdenum  roasting opera-
tions.  The technology basis for the  existing BPT limitations is
chemical precipitation and sedimentation technology  to remove
metals and solids  from combined wastewaters  and to control  pH.
These technologies are already in-place at both of the discharg-
ers included  under the expanded applicability.   The  pollutants
specifically  proposed for  regulation  at BPT  are cadmium,  copper,
lead, zinc, TSS,  and pH.   The BPT  treatment  scheme for
metallurgical acid plants  is presented  in Figure IX-2.

Compliance with the existing BPT limitations for metallurgical
acid  plants by  the two direct discharging primary molybdenum
facilities which  operate sulfuric  acid  plants will result in the
removal of an estimated 8,026 kg of toxic metals, 381  kg of
molybdenum, and 10,908 kg  of TSS annually over  estimated current
discharge.  While  both plants have the  equipment in-place to
comply with BPT, we do not believe that the  plants are  currently
achieving  the BPT  limitations.  The estimated capital  and annual
cost  for achieving BPT cannot be presented here because the data
on which they are based have been  claimed to be confidential.

WASTEWATER DISCHARGE RATES

A BPT discharge rate is calculated for  each  subdivision based on
the average of the flows of  the existing plants, as  determined
from  analysis of dcp.  The discharge  rate is used with the
achievable treatment concentration to determine BPT  effluent
limitations.  Since the discharge  rate  may be different for each
wastewater source, separate  production  normalized discharge rates
for each of the six wastewater sources  are discussed below  and
summarized in Table IX-1.  The discharge rates  are normalized on
a production basis by relating the amount of wastewater generated
to the mass of the product which is produced by the  process asso-
ciated with the waste stream in question.  These production
normalizing parameters, or PNPs,  are  listed  in  Table IX-1.

Section V of this document further describes the discharge  flow
rates and presents the water use and  discharge  flow  rates for
each plant by subdivision.

MOLYBDENUM SULFIDE LEACHING

The BPT wastewater discharge rate  for molybdenum sulfide  leaching
is 463 1/kkg  (112 gal/ton) of molybdenum sulfide concentrate
                                97
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leached prior to roasting.  This rate  is  allocated  only  to facil-
ities which leach molybdenum sulfide concentrates to  remove
excess alkali, prior to roasting.  One  of the  seven plants which
roasts molybdenite practices leaching prior to  roasting.   The
water use and discharge rate are presented in Table V-1.   This
facility currently achieves zero discharge of  this  stream  through
the use of evaporation ponds and contract hauling.  The  possibil-
ity for achieving zero discharge of this  stream in  this  manner  is
site-specific and therefore not applicable on  a nationwide basis.
The leaching and rinsing flow reported  by this  facility  was used
as the basis for the BPT flow allowance for this stream.

ROASTER S0£ SCRUBBER

The BPT wastewater discharge rate for molybdenite roaster  S02
scrubber wastewater is 1,679 1/kkg (404 gal/ton) of molybdenum
sulfide roasted.  This rate is allocated  only  to those plants
which use scrubbers to control S02 emissions from molybdenum
sulfide roaster flue gases.  Four of the  seven  plants which roast
molybdenum sulfide concentrates use scrubbers  to control S02
emissions.  Three of these facilities use caustic scrubbers and
achieve zero discharge through the use  of tailings  ponds or per-
manent impoundments.  One facility uses an ammonia  scrubbing
solution and achieves zero discharge by using  the scrubber liquor
as feed material to a fertilizer plant.   One of the four facili-
ties did not report actual flow rates for this  stream.   The BPT
flow rate was based on the production normalized flows from two
facilities which reported flow rates for  scrubbing  systems.  The
production normalized flow reported by  plant 1174 was not  used
because the reported water use was inordinately high, and  not
characteristic of effective wet air pollution  control systems.

MOLYBDIC OXIDE LEACHATE

The BPT wastewater discharge rate for molybdic  oxide  leachate is
7,630 1/kkg (1,828 gal/ton) of ammonium molybdate product.   This
rate is applicable only to those plants which produce ammonium
molybdate through leaching and dissolving molybdic  oxide,  and
crystallizing ammonium molybdate product.  Three of the  seven
plants which produce technical grade molybdic oxide also produce
ammonium molybdate.  The water use and  discharge rates for two  of
the facilities are presented in Table V-3.  The remaining  plant
which produces ammonium molybdate uses  an evaporator  in  the pro-
cess and generates no wastewater.  A representative for  the
facility, however, indicated that they  plan to  change from the
evaporative process and will need to discharge  wastewater  in the
near future.  The BPT regulatory flow was based on  the average
production normalized water use of the  two plants which  reported
discharging this wastewater.  One of the  two plants which
generates process wastewater from the ammonium  molybdate process
                                98
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achieves  zero discharge  through  the  use  of an evaporation pond
and contract hauling.  The possibility for achieving zero
discharge  in this manner is  site-specific  and therefore not
applicable on a nationwide basis.

HYDROGEN REDUCTION  FURNACE SCRUBBER

The BPT wastewater  discharge rate  for reduction  furnace hydrogen
scrubbing  is 22,898 1/kkg  (5,505 gal/ton)  of  molybdenum metal
powder produced.  This rate  is applicable  only to  those plants
which practice wet  scrubbing of hydrogen gas  used  in reduction
furnaces.  Two of the four plants  which  use reduction furnaces to
produce molybdenum metal powder  from either pure molybdic oxide
or ammonium molybdate reported the use of  wet scrubbing.   The
water use and discharge  rates are  presented in Table V-4.  The
BPT flow rate is based on the average of the  water use  at these
two facilities.  One of  the  facilities reported  0  percent recy-
cle.  The other facility reported  recycle  but did  not specify the
recycle ratio.  The recycle  ratio  at this  facility was  assumed to
be 99 percent and the water use was  calculated from the discharge
rate by dividing the discharge flow  by 0.01,  yielding a water use
of 2,000 1/kkg.  The water use and discharge  flow  rates for the
facility which practices no  recycle  are  the same.   This facility
reported a reduction furnace scrubber flow rate  of 43,795 1/kkg.
The BPT flow rate is based on the  average  of  the water  use rates
at these two facilities.

DEPLETED RHENIUM SCRUBBING SOLUTION

The BPT wastewater discharge rate  for depleted rhenium  scrubbing
solution is 716 1/kkg (173 gal/ton)  of molybdenum  sulfide
roasted.  This rate is applicable  only to  those  facilities which
recover crude ammonium perrhenate  from molybdenite roaster flue
gases.  Two of the seven plants which roast molybdenite concen-
trates reported that they recover  rhenium  from roaster  flue
gases.  The water use and discharge  rates  are  presented in Table
V-5.  Both of the facilities which practice rhenium recovery
achieve zero discharge through the use of  evaporation ponds,  con-
tract hauling or recycle to other  plant  processes.   The possibil-
ity of achieving zero discharge in this  manner is  site-specific
and therefore not applicable on a  nationwide  basis.   The  BPT flow
rate is based on the average of the  production normalized water
use rates reported by the two facilities reporting this stream.
The production normalized flow rates used  in  the average  are 637
1/kkg and 794 1/kkg.

SULFURIC ACID PLANT SLOWDOWN

EPA promulgated best practicable control technology currently
available (BPT)  effluent limitations guidelines  for the metal-
lurgical acid plants subcategory of  the  nonferrous metals manu-
facturing category on July 2, 1980.  The BPT wastewater flow rate
                               99
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was determined to be 6,079 1/kkg (1,457 gal/ton) of 100 percent
equivalent sulfuric acid capacity.  EPA is presently expanding
the applicability of this regulation to encompass the molybdenum
sulfuric acid plants.  Table V-6 shows the production normalized
flows reported for the three plants in the primary molybdenum and
rhenium subcategory that report a sulfuic acid plant blowdown
waste stream.  It is noted that the promulgated BPT regulatory
flow is greater than any of the reported production normalized
flows.

REGULATED POLLUTANT PARAMETERS

The raw wastewater concentrations from individual operations and
the subcategory as a whole were examined to select certain pollu-
tant parameters for limitation.  This examination and evaluation
was presented in Section VI.  A total of eight pollutants or pol-
lutant parameters were selected for limitation and are listed
below:

     115.  arsenic
     122.  lead
     124.  nickel
     125.  selenium
           ammonia
           fluoride*
           molybdenum
           total suspended solids
           pH

The regulated pollutant parameters for metallurgical acid plants
are listed below:

     118.  cadmium
     120.  copper
     122.  lead
     128.  zinc
           fluoride*
           total suspended solids
           pH

*The Agency is considering limiting the pollutant fluoride in
 this subcategory and is soliciting comments from the industry.
 Effluent limitations for fluoride would be based on treatment
 effectiveness concentrations of 19.9 mg/1 for the monthly
 average and 35 mg/1 for the daily maximum.  A complete discus-
 sion of fluoride may be found in Section VII of the General
 Development Document under treatment performances of additional
 pollutants.  The treatment effectiveness of fluoride is based on
 data from the Electrical and Electronic Components Phase II
 Category.
                               100
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EFFLUENT LIMITATIONS

The treatability concentrations achievable by application of  the
proposed BPT treatment are explained in Section VII of the Gen-
eral Development Document and summarized there in Table VI1-19.
The achievable treatment concentrations (both one day maximum and
monthly average values) are multiplied by the BPT normalized  dis-
charge flows summarized in Table IX-1 to calculate the mass of
pollutants allowed to be discharged per mass of product.  The
results of these calculations in milligrams of pollutant per
kilogram of product represent the BPT effluent limitations and
are presented in Table IX-2 for each individual waste stream.
The BPT effluent limitations for metallurgical acid plants are
presented in Table IX-3.
                               101
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                       Table  IX-2

              BPT MASS LIMITATIONS FOR  THE
       PRIMARY MOLYBDENUM AND RHENIUM SUBCATEGORY
 (a)  Molybdenum Sulfide Leaching

   Pollutant or        Maximum for       Maximum  for
 Pollutant Property	Any One Day	Monthly Average

  mg/kg  (Ib/million Ibs) of molybdenum sulfide leached

Arsenic                   0.968              0.431
 Lead                      0.195              0.093
 Nickel                    0.889              0.588
 Selenium                  0.570              0.255
Molybdenum                2.676              1.190
Ammonia  (as N)           61.720             27.130
 Total suspended          18.990              9.029
  solids
pH                     Within the range of  7.5 to 10.0
                                 at all times
(b)  Roaster S02 Scrubber

   Pollutant or        Maximum for       Maximum for
Pollutant Property	Any One Day	Monthly Average

  mg/kg (Ib/million Ibs) of molybdenum sulfide roasted

Arsenic                   3.509              1.561
Lead                      0.705              0.336
Nickel                    3.224              2.133
Selenium                  2.065              0.924
Molybdenum                9.705              4.315
Ammonia (as N)          223.800            98.390
Total suspended          68.840            32.740
  solids
pH                     Within the range of 7.5 to 10.0
                                 at all times
                              103
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                 Table IX-2 (Continued)

              BPT MASS LIMITATIONS FOR THE
       PRIMARY MOLYBDENUM AND RHENIUM SUBCATEGORY
(c)  Molybdic Oxide Leachate

   Pollutant or        Maximum for       Maximum for
Pollutant Property	Any One Day	Monthly Average

      rog/kg (Ib/million Ibs) of ammonium molybdate
                        produced

Arsenic                  15.950             7.096
Lead                      2.983             1.421
Nickel                   13.640             9.020
Selenium                  8.736             3.906
Molybdenum               44.100            19.610
Ammonia (as N)        1,017.000           447.100
Total suspended         291.200           138.500
  solids
pH                     Within the range of 7.5 to 10.0
                                 at all times
(d)  Hydrogen Reduction Furnace Scrubber

   Pollutant or        Maximum for       Maximum for
Pollutant Property	Any One Day	Monthly Average

   mg/kg (Ib/million Ibs) of molybdenum metal powder
                        produced

Arsenic                  47.860            21.300
Lead                      9.617             4.580
Nickel                   43.970            29.080
Selenium                 28.170            12.600
Molybdenum              132.400            58.850
Ammonia (as N)        3,052.000         1,342.000
Total suspended         938.800           446.500
  solids
pH                     Within the range of 7.5 to 10.0
                                 at all times
                               104
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                 Table IX-2  (Continued)

              BPT MASS LIMITATIONS FOR THE
       PRIMARY MOLYBDENUM AND RHENIUM SUBCATEGORY
(e)  Depleted Rhenium Scrubbing Solution

   Pollutant or        Maximum for       Maximum  for
Pollutant Property	Any One Day	Monthly Average

  mg/kg (Ib/million Ibs) of molybdenum sulfide roasted

Arsenic                   1.497             0.666
Lead                      0.301             0.143
Nickel                    1.375             0.909
Selenium                  0.881             0.394
Molybdenum                4.138             1.840
Ammonia (as N)           95.440            41.960
Total suspended          29.360            13.960
  solids
pH                     Within the range of 7.5 to 10.0
                                 at all times
                              105
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                           Table IX-3

     BPT EFFLUENT LIMITATIONS FOR METALLURGICAL ACID PLANTS

Effluent Characteristic

Effluent Limitations
Maximum for
any 1 day
Average of
daily values
for 30
consecutive
days shall
not exceed
Total suspended solids
Copper	
Cadmium	
Lead	
Zinc	
pH	
                                 Metric units,  kg/kkg of product

                                 English units,  pounds per
                                 1,000 pounds of product
0.304
0.005
0.00018
0.0018
0.0036
0.152
0.002
0.00009
0.00079
0.0009
1 Within the range of 6.0 to 9.0
                               106
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            PRIMARY MOLYBDENUM AND RHENIUM SUBCATEGORY

                            SECTION X

        BEST AVAILABLE TECHNOLOGY ECONOMICALLY ACHIEVABLE


The effluent limitations which must be achieved by July 1, 1984
are based on the best control and treatment technology used by a
specific point source within the industrial category or subcate-
gory, or by another industry where it is readily transferable.
Emphasis is placed on additional treatment techniques applied at
the end of the treatment systems currently used, as well as
reduction of the amount of water used and discharged, process
control, and treatment technology optimization.

The factors considered in assessing best available technology
economically achievable (BAT) include the age of equipment and
facilities involved, the manufacturing process used, process
changes, nonwater quality environmental impacts (including energy
requirements), and the costs of application of such technology
(Section 304  (b)(2)(B) of the Clean Water Act).  At a minimum
BAT technology represents the best available technology at plants
of various ages,  sizes, processes, or other characteristics.  As
with BPT, where the Agency has found the existing performance to
be uniformly inadequate,  BAT may be transferred from a different
subcategory or category.   BAT may include feasible process
changes or internal controls, even when not in common industry
practice.

The statutory assessment of BAT considers costs, but does not
require a balancing of costs against pollutant removal benefits
(see Weyerhaeuser v. Costle. 11  ERG 2149 (D.C. Cir. 1978).).
However, in assessing the proposed BAT,  the Agency has given
substantial weight to the economic achievability of the selected
technology.

TECHNICAL APPROACH TO BAT

The Agency reviewed a wide range of technology options and evalu-
ated the available possibilities to ensure that the most effec-
tive and beneficial technologies were used as the basis of BAT.
To accomplish this, the Agency elected to examine three technol-
ogy options which could be applied to the primary molybdenum and
rhenium subcategory as treatment options for the basis of BAT
effluent limitations.

For the development of BAT effluent limitations, mass loadings
were calculated for each wastewater source or subdivision in the
subcategory using the same technical approach as described in
                              109
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Section IX for BPT limitations development.  The differences  in
the mass loadings for BPT and BAT are due to increased treatment
effectiveness achievable with the more sophisticated BAT  treat-
ment technology and reductions in the effluent flows usually
achieved by recycle and reuse technologies.

In summary, the treatment technologies considered for BAT are
presented below:

Option A (Figure X-1) is based on

     •  Preliminary treatment with ammonia steam stripping
     •  Chemical precipitation and sedimentation

Option B (Figure X-2) is based on

     •  Preliminary treatment with ammonia steam stripping
     •  Chemical precipitation and sedimentation
     •  In-process flow reduction

Option C (Figure X-3) is based on

     •  Preliminary treatment with ammonia steam stripping
     •  Chemical precipitation and sedimentation
     •  In-process flow reduction
     •  Multimedia filtration

The promulgated treatment technologies for the metallurgical acid
plants are presented below for BAT (Figure X-5):

     •  Preliminary treatment with sulfide precipitation  and
        pressure filtration
     •  Chemical precipitation and sedimentation
     •  In-process flow reduction
     •  Multimedia filtration

The three options examined for BAT and the promulgated BAT
treatment technologies for metallurgical acid plants are  dis-
cussed in greater detail below.  The first option considered is
the same as the BPT treatment which was presented in the  previous
section.  The last two options each represent substantial
progress toward the prevention of polluting the environment above
and beyond the progress achievable by BPT.

OPTION A

Option A for the primary molybdenum and rhenium subcategory is
equivalent to the control and treatment technologies which were
analyzed for BPT in Section IX.  The BPT end-of-pipe treatment
scheme includes chemical precipitation, sedimentation, with
                                no
-------
ammonia  steam stripping preliminary  treatment  (see  Figure  X-1).
The discharge rates for Option A are  equal  to  the discharge  rates
allocated to each stream as a BPT discharge flow.

OPTION B

Option B for the primary molybdenum  and  rhenium  subcategory
achieves lower pollutant discharge by building upon  the Option A
end-of-pipe treatment technology, which  consists of  ammonia  steam
stripping, chemical precipitation, and sedimentation.  Flow
reduction measures are added to Option A treatment  (see Figure
X-2).  These flow reduction measures, including  in-process
changes, result in the elimination of some  wastewater  streams and
the concentration of pollutants in other effluents.  Treatment of
a more concentrated effluent allows  achievement  of a greater net
pollutant removal and introduces the  possible  economic benefits
associated with treating a lower volume  of  wastewater.

The method used in Option B to reduce process  wastewater genera-
tion or discharge rates is recycle of water used in  wet air  pol-
lution control.  There are two wastewater sources associated with
wet air pollution control or gas cleaning and  quenching prior to
recycle which are regulated under these  effluent limitations:

     --Roaster S02 scrubber, and
     --Hydrogen reduction furnace scrubber.

Table X-1 presents the number of plants  reporting wastewater use
with these sources, the number of plants practicing  recycle  of
scrubber water, and the range of recycle values being used.

The BAT regulatory flow for hydrogen  reduction furnace scrubbers
is based on recycle of scrubber liquor as discussed  later  in this
section, and represents the best available  technology economi-
cally achievable for this stream.  The BAT  regulatory flow for
roaster S02 scrubbers will not be flow reduced because the
Agency believes that flow reduction beyond  the BPT regulatory
flow is not warranted.

OPTION C

Option C for the primary molybdenum and  rhenium subcategory
consists of all control and treatment requirements of Option B
(ammonia steam stripping,  in-process  flow reduction, chemical
precipitation, and sedimentation) plus multimedia filtration
technology added at the end of the Option B  treatment scheme (see
Figure X-3).  Multimedia filtration is used  to remove suspended
solids, including precipitates of toxic  metals, beyond the con-
centrations attainable by gravity sedimentation alone.  The
filter suggested is of the gravity, mixed media type, although
                               1 11
-------
other filters, such as rapid sand  filters  or  pressure  filters,
would perform as well.

METALLURGICAL ACID PLANTS

The promulgated limitations for metallurgical acid plants are
based on in-process flow reduction, chemical  precipitation  and
sedimentation, sulfide precipitation and sedimentation,  followed
by multimedia filtration for lead  and zinc acid plants  (Figure
X-4).  For copper acid plants, the promulgated BAT treatment
technology is based on in-process  flow reduction, sulfide precip-
itation, pressure filtration, chemical precipitation and sedimen-
tation, and multimedia filtration  (Figure X-5).  The Agency is
proposing expanding the metallurgical acid plants BAT  limitations
to include molybdenum acid plants  based on sulfide precipitation
and pressure filtration pretreatment, followed by chemical  pre-
cipitation and sedimentation, and multimedia  filtration  as
presented in Figure X-5.

INDUSTRY COST AND POLLUTANT REMOVAL ESTIMATES

As one means of evaluating each technology option, EPA developed
estimates of the pollutant removal estimates  and the compliance
costs associated with each option.  The methodologies  are
described below.

POLLUTANT REMOVAL ESTIMATES

A complete description of the methodology used to calculate the
estimated pollutant removal, achieved by the  application of the
various treatment options is presented in Section X of  the
General Development Document.  In  short, sampling data collected
during the field sampling program were used to characterize the
major waste streams considered for regulation.  At each  sampled
facility, the sampling data was production normalized  for each
unit operation (i.e., mass of pollutant generated per mass  of
product manufactured).  This value, referred  to as the  raw  waste,
was used to estimate the mass of toxic pollutants generated
within the primary molybdenum and  rhenium subcategory.   The pol-
lutant removal estimates were calculated for  each plant  by  first
estimating the total mass of each  pollutant in the untreated
wastewater.  This was calculated by first multiplying  the raw
waste values by the corresponding  production  value for  that
stream and then summing these values for each pollutant  for every
stream generated by the plant.

Next, the volume of wastewater discharged after the application
of each treatment option was estimated for each operation at each
plant by first comparing the actual discharge to the regulatory
flow.  The smaller of the two values was selected and  summed with
                               112
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the other plant  flows.  The mass  of  pollutant  discharged  was  then
estimated by multiplying  the achievable  concentration  values
attainable with  the option  (mg/1) by the estimated  volume of  pro-
cess wastewater  discharged by  the subcategory.   Finally,  the  mass
of pollutant removed  is the difference between the  estimated  mass
of pollutant generated by each plant in  the  subcategory and the
mass of pollutant discharged after application of the  treatment
option.  The pollutant removal estimates for direct dischargers
in the primary molybdenum and  rhenium subcategory are  presented
in Table X-2.  The pollutant removal estimates for  metallurgical
acid plants associated with primary  molybdenum operations are
presented in Table X-3.

COMPLIANCE COST

In estimating subcategory-wide compliance  costs,  the first step
was to develop a cost estimation model,  relating the total costs
associated with  installation and  operation of  wastewater  treat-
ment technologies to plant process wastewater  discharge.   EPA
applied the model to each plant.  The plant's  investment  and
operating costs  are determined by what treatment it has in place
and by its individual process  wastewater discharge  flow.   As  dis-
cussed above, this flow is either the actual or the BAT regula-
tory flow, whichever is lesser.  The final step was to annualize
the capital costs, and to sum  the annualized capital costs, and
the operating and maintenance  costs  for  each plant,  yielding  the
cost of compliance for the subcategory (See  Table X-4).   These
costs were used  in assessing economic achievability.   The cost  of
compliance for metallurgical acid plants associated with  primary
molybdenum operations are presented  in Table X-5.

BAT OPTION SELECTION

EPA has selected Option C as the basis for BAT in this subcate-
gory.  Option C  consists  of the BPT  technology (chemical  precipi-
tation and sedimentation), in-process wastewater  reduction, and
multimedia filtration.  Flow reductions  are  based on 90 percent
recycle of scrubber liquor, a  rate surpassed by one of the two
direct discharger plants.

Implementation of the proposed BAT limitations  would remove annu-
ally an estimated 73,655  kg of toxic  metals, which  is  24  kg of
toxic metals over the estimated BPT  discharge.   No  additional
ammonia is removed at BAT.  The estimated  capital and  annual  cost
for achieving proposed BAT cannot be  presented  here because the
data on which they are based have been claimed  to be confiden-
tial.

The intermediate option we considered for  BAT  is  flow  reduction
plus the proposed technology basis for BPT.  This option  would
                               113
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remove an estimated 13 kg of toxic metals  over  the  estimated  BPT
discharge.  The estimated capital and annual cost for achieving
this option cannot be presented here because the data on which
they are based have been claimed to be confidential.

We are expanding the applicability of the  existing  BAT  limita-
tions for metallurgical acid plants to include  acid plants  asso-
ciated with primary molybdenum roasting operations.  The existing
promulgated BAT limitations are based on treatment  technology
consisting of in-process wastewater reduction,  sulfide  precipita-
tion preliminary treatment, chemical precipitation  and  sedimenta-
tion, and multimedia filtration.  Flow reductions are based on 90
percent recycle of scrubber liquor.  Both  of the plants included
under the expanded applicability currently discharge less waste-
water than the BAT flow allowance of 2,554 1/kkg (612.5 gal/ton)
of 100 percent sulfuric acid production capacity.

Compliance with the existing BAT limitations for metallurgical
acid plants by the two direct discharging  primary molybdenum
facilities which operate sulfuric acid plants will  result in  the
annual removal of an estimated 8,245 kg of toxic pollutants,
which is 219 kg of toxic metals over the estimated  BPT  discharge.
The estimated capital and annual costs for achieving BAT for  the
molybdenum acid plants cannot be presented here because the data
on which they are based have been claimed  to be confidential.

We are proposing filtration as part of the BAT  technology because
this technology is demonstrated in the nonferrous metals manufac-
turing category (25 facilities presently have filters), and
results in additional removals of toxic metals.  In addition,
filtration adds reliability to the treatment system by  making it
less susceptible to operator error and to  sudden changes in raw
wastewater flows and concentrations.

WASTEWATER DISCHARGE RATES

A BAT discharge rate was calculated for each subdivision based
upon the flows of the existing plants, as  determined from analy-
sis of dcp.  The discharge rate is used with the achievable
treatment concentration to determine BAT effluent limitations.
Since the discharge rate may be different  for each  wastewater
source, separate production normalized discharge rates  for  each
of the five wastewater sources were determined  and  are  summarized
in Table X-4.  The discharge rates are normalized on a  production
basis by relating the amount of wastewater generated to the mass
of the product which is produced by the process associated with
the waste stream in question.  These production normalizing para-
meters (PNP) are also listed in Table X-6.
                               114
-------
The BAT wastewater discharge  rate  equals  the  BPT wastewater dis-
charge rate for four  of  the six waste  streams  in the  primary
molybdenum and rhenium subcategory.  Based  on  the available data,
the Agency did not find  that  further flow reduction would  be
feasible  for these wastewater sources.  The rationale for  deter-
mining the regulatory flows for these  four  streams was  previously
presented in Section  IX.  Wastewater streams  for which  BAT dis-
charge rates differ from BPT  are discussed  below.

HYDROGEN REDUCTION FURNACE SCRUBBER

The BAT wastewater discharge  rate  for  hydrogen reduction furnace
scrubber water is 2,290  1/kkg (550 gal/ton).   This rate is allo-
cated only to those plants which practice water scrubbing  of
recirculating hydrogen gas from reduction furnaces.   The BAT dis-
charge rate is based  on  90 percent recycle  of  the  average  water
use of the two plants reporting this stream.   One  facility cur-
rently practices extensive recycle (assumed to be  greater  than 99
percent as discussed  in  Section IX) and the other  currently
practices no recycle.  Water  use and discharge rates  are
presented in Table V-4.

SULFURIC ACID PLANT SLOWDOWN

The promulgated BAT wastewater discharge  rate  for  sulfuric acid
plant blowdown wastewater is  2,554 1/kkg  (612.5 gallons/ton)  of
100 percent sulfuric  acid production capacity.   This  rate,  prom-
ulgated on'March 8, 1984, is  allocated only to those  plants  which
use an acid plant to  convert  S02 gas emissions from the molyb-
denite roaster to sulfuric acid.  For  a discussion of how  the BAT
regulatory flow was determined, refer  to  the Metallurgical Acid
Plants Subcategory Development Document.  The  production normal-
ized flows reported by three  plants in the  primary molybdenum and
rhenium subcategory that have an acid  plant blowdown  waste  stream
are shown in Table V-6.   It can be noted  that  the present  dis-
charge rates for these three  plants are below  the promulgated BAT
regulatory flow for this waste stream.

REGULATED POLLUTANT PARAMETERS

In implementing the terms of  the Consent  Agreement in NRDC v.
Train, Op. Git.,  and 33 U.S.C. 1314(b)(2)(A and  B) (197^77 the
Agency placed particular emphasis on the  toxic pollutants.   The
raw wastewater concentrations from individual  operations and  the
subcategory as a whole were examined to select certain  pollutants
and pollutant parameters for  limitation.  This  examination  and
evaluation was presented in Section VI.   The Agency,  however, has
chosen not to regulate all nine toxic pollutants selected  in  this
analysis.
                               115
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The high cost associated with analysis for toxic metal pollutants
has prompted EPA to develop an alternative method for regulating
and monitoring toxic pollutant discharges from the nonferrous
metals manufacturing category.  Rather than developing specific
effluent mass limitations and standards for each of the toxic
metals found in treatable concentrations in the raw wastewater
from a given subcategory, the Agency is proposing effluent mass
limitations only for those pollutants generated in the greatest
quantities as shown by the pollutant removal estimate analysis.
The pollutants selected for specific limitation are listed below:

     115.  arsenic
     122.  lead
     124.  nickel
     125.  selenium
           ammonia (as N)
           fluoride*
           molybdenum

By establishing limitations and standards for certain toxic metal
pollutants, dischargers will attain the same degree of control
over toxic metal pollutants as they would have been required to
achieve had all the toxic metal pollutants been directly limited.

This approach is technically justified since the treatable con-
centrations used for chemical precipitation and sedimentation
technology are based on optimized treatment for concomitant mul-
tiple metals removal.  Thus, even though metals have somewhat
different theoretical solubilities, they will be removed at very
nearly the same rate in a chemical precipitation and sedimenta-
tion treatment system operated for multiple metals removal.
Filtration as part of the technology basis is likewise justified
because this technology removes metals non-preferentially.

The toxic metal pollutants selected for specific limitation in
the primary molybdenum and rhenium subcategory to control the
discharges of toxic metal pollutants are arsenic, lead, nickel,
and selenium.  Ammonia is also selected for limitation since the
methods used to control the regulated toxic pollutants are not
effective in the control of ammonia.  The following toxic pollu-
tants are excluded from limitation on the basis that they are
effectively controlled by the limitations developed for arsenic,
lead, nickel, and selenium:

     119.  chromium (Total)
     120.  copper
     128.  zinc

The regulated pollutants for the metallurgical acid plants are
listed below:
                                116
-------
     115.  arsenic
     118.  cadmium
     120.  copper
     122.  lead
     128.  zinc
           fluoride*

*The Agency is considering limiting the pollutant fluoride in
 this subcategory and is soliciting comments from the industry.
 Effluent limitations for fluoride would be based on treatment
 effectiveness concentrations of 19.9 mg/1 for the monthly aver-
 age and 35 mg/1 for the daily maximum.  A complete discussion
 of fluoride may be found in Section VII of the General Develop-
 ment Document under treatment performances of additional pollu-
 tants.  The treatment effectiveness of fluoride is based on data
 from the Electrical and Electronic Components Phase II Category.

EFFLUENT LIMITATIONS

The concentrations achievable by application of BAT are discussed
in Section VII of the General Development Document and summarized
there in Table VII-19.  The treatability concentrations including
both one day maximum and monthly average values are multiplied by
the BAT normalized discharge flows summarized in Table X-6 to
calculate the mass of pollutants allowed to be discharged per
mass of product.  The results of these calculations in milligrams
of pollutant per kilogram of product represent the BAT effluent
limitations and are presented in Table X-7 for each waste stream.
The BAT limitations for metallurgical acid plants are presented
in Table X-8.
                               117
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-------
                            Table X-4

                    COST OF COMPLIANCE FOR THE
            PRIMARY MOLYBDENUM AND RHENIUM SUBCATEGORY
                        DIRECT DISCHARGERS
The compliance costs for this subcategory cannot be presented
here because the data on which they are based have been claimed
to be confidential.
                              121
-------
                            Table X-5

         COST OF COMPLIANCE FOR METALLURGICAL ACID PLANTS
          ASSOCIATED WITH PRIMARY MOLYBDENUM OPERATIONS
                        DIRECT DISCHARGERS
The compliance costs for this subcategory cannot be presented
here because the data on which they are based have been claimed
to be confidential.
                              122
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                       Table X-7

              BAT MASS LIMITATIONS FOR THE
       PRIMARY MOLYBDENUM AND RHENIUM SUBCATEGORY
(a)  Molybdenum Sulfide Leaching

   Pollutant or        Maximum for       Maximum for
Pollutant Property	Any One Day	Monthly Average

  mg/kg (Ib/million Ibs) of molybdenum sulfide leached

Arsenic                   0.644             0.287
Lead                      0.130             0.060
Nickel                    0.255             0.171
Selenium                  0.380             0.171
Molybdenum                1.783             0.792
Ammonia (as N)           61.720            27.130
(b)  Roaster S02 Scrubber

   Pollutant or        Maximum for       Maximum for
Pollutant Property	Any One Da.y	Monthly Average

  mg/kg (Ib/million Ibs) of molybdenum sulfide roasted

Arsenic                   2.334              1.041
Lead                      0.470              0.218
Nickel                    0.924              0.621
Selenium                  1.377              0.621
Molybdenum                6.464              2.871
Ammonia (as N)          223.800            93.390
(c)  Molybdic Oxide Leachate

   Pollutant or        Maximum for       Maximum for
Pollutant Property	Any One Day	Monthly Average

      mg/kg (Ib/million Ibs) of ammonium molybdate
                        produced

Arsenic                  10.610             4.731
Lead                      1.989             0.923
Nickel                    3.906             2.628
Selenium                  5.824             2.628
Molybdenum               29.380             13.050
Ammonia (as N)        1,017.000           447.100
                               124
-------
                 Table X-7  (Continued)

              BAT MASS LIMITATIONS FOR  THE
       PRIMARY MOLYBDENUM AND RHENIUM SUBCATEGORY
(d)  Hydrogen Reduction Furnace Scrubber

   Pollutant or        Maximum for       Maximum  for
Pollutant Property	Any One Day	Monthly Average

   mg/kg (Ib/million Ibs) of molybdenum metal powder
                        produced

Arsenic                   3.183              1.420
Lead                      0.641              0.298
Nickel                    1.260              0.847
Selenium                  1.878              0.847
Molybdenum                8.817              3.916
Ammonia (as N)          305.300            134.200
(e)  Depleted Rhenium Scrubbing Solution

   Pollutant or        Maximum for       Maximum for
Pollutant Property 	Any One Day	Monthly Average

  mg/kg (Ib/million Ibs) of molybdenum sulfide roasted

Arsenic                   0.995             0.444
Lead                      0.201             0.093
Nickel                    0.394             0.265
Selenium                  0.587             0.265
Molybdenum                2.757             1.224
Ammonia (as N)           95.440            41.960
                               125
-------
                      Table X-8

BAT EFFLUENT LIMITATIONS FOR METALLURGICAL ACID PLANTS

Pollutant or pollutant property
BAT Effluent Limitations
Maximum
for any
1 day
Maximum
for monthly
average
                            (Mg/kg pounds per million
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                             acid capacity

Cadmium 	




3.550
.51 1
3.269
.715
2.605

1 .456
.204
1 .558
.332
1 .073

                         126
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            PRIMARY MOLYBDENUM AND  RHENIUM SUBCATEGORY

                            SECTION XI

                 NEW  SOURCE PERFORMANCE  STANDARDS


The basis for new source performance standards  (NSPS) under
Section 306 of the Act is the best  available demonstrated  tech-
nology (BDT).  New plants have the  opportunity  to design the  best
and most efficient production processes  and wastewater  treatment
technologies without  facing the added costs and restrictions
encountered in retrofitting an existing  plant.  Therefore,
Congress directed EPA to consider the best demonstrated process
changes, in-plant controls, and end-of-pipe treatment technolo-
gies which reduce pollution to the  maximum extent feasible.

This section describes the technologies  for treatment of waste-
water from new sources and presents mass discharge  standards  for
regulatory pollutants for NSPS in the primary molybdenum and
rhenium subcategory,  based on the selected treatment technology.

TECHNICAL APPROACH TO NSPS

New source performance standards are equivalent to  the best
available technology  (BAT) selected for  currently existing
primary molybdenum and rhenium plants.   This result is a conse-
quence of careful review by the Agency of a wide range of tech-
nical options for new source treatment systems which is discussed
in Section XI of the  General Development Document.  This review
of the primary molybdenum and rhenium subcategory found no new,
economically feasible, demonstrated technologies which could  be
considered an improvement over those chosen for consideration for
BAT.  Additionally, there was nothing found to indicate that  the
wastewater flows and  characteristics of new plants would not  be
similar to those from existing plants, since the processes used
by new sources are not expected to  differ from those used at
existing sources.  For metallurgical acid plants, the promulgated
limitations and standards include NSPS equal to BAT.  Since EPA
is proposing to expand the applicability of the metallurgical
acid plants regulation to include molybdenum acid plants, the
standards for new source molybdenum acid plants are equal to
those for BAT.  Consequently, BAT production normalized discharge
rates, which are based on the best  existing practices of the
subcategory, can also be applied to new  sources. These rates  are
presented in Table XI-1.

Treatment technologies considered for the NSPS options are
identical to the treatment technologies considered for the BAT
options.   These options  are:
                               133
-------
OPTION A
     •  Preliminary treatment with ammonia  steam  stripping
        (where required)
     •  Chemical precipitation and sedimentation
OPTION B
     •  Preliminary treatment with ammonia steam stripping
        (where required)
     •  Chemical precipitation and sedimentation
     •  In-process flow reduction of hydrogen reduction furnace
        scrubber liquor

OPTION C

     •  Preliminary treatment with ammonia steam stripping
        (where required)
     •  Chemical precipitation and sedimentation
     •  In-process flow reduction of hydrogen reduction furnace
        scrubber liquor
     •  Multimedia filtration

The promulgated treatment technologies for the metallurgical acid
plants are presented below for NSPS:

     •  Preliminary treatment with sulfide precipitation and
        pressure filtration
     •  Chemical precipitation and sedimentation
     •  In-process flow reduction
     •  Multimedia filtration

NSPS OPTION SELECTION

We are proposing that NSPS be equal to BAT.  Our review of the
industry indicates that no new demonstrated technologies that
improve on BAT technology exist.

The wastewater flow rates for NSPS are the same as the BAT flow
rates because we do not believe that new plants could achieve any
additional flow reduction beyond the 90 percent scrubber effluent
recycle proposed for BAT.

We are expanding the applicability of the existing NSPS regula-
tion for the metallurgical acid plants subcategory to include
acid plants associated with primary molybdenum roasting
operations.
                               134
-------
REGULATED POLLUTANT PARAMETERS

The Agency has no reason to believe that the pollutants that will
be found in treatable concentrations in processes within new
sources will be any different than with existing sources.
Accordingly, pollutants and pollutant parameters selected for
limitation under NSPS, in accordance with the rationale of
Sections VI and X, are identical to those selected for BAT.  The
conventional pollutant parameters TSS and pH are also selected
for limitation.  The Agency is considering limiting the pollutant
fluoride in this subcategory and is soliciting comments from the
industry.  Effluent limitations for fluoride would be based on
treatment effectiveness concentrations of 19.9 mg/1 for the
monthly average and 35 mg/1 for the daily maximum.  A complete
discussion of fluoride may be found in Section VII of the General
Development Document under treatment performances of additional
pollutants.  The treatment effectiveness of fluoride is based on
data from the Electrical and Electronic Components Phase II
Category.

NEW SOURCE PERFORMANCE STANDARDS

The NSPS discharge flows for each wastewater source are the same
as the discharge rates for BAT and are shown in Table XI-1.  The
mass of pollutant allowed to be discharged per mass of product is
calculated by multiplying the appropriate treatable concentration
(mg/1) by the production normalized wastewater discharge flows
(1/kkg).  The treatable concentrations are listed in Table VI1-19
of the General Development Document.  The results of these calcu-
lations are the production-based new source performance stan-
dards.  These standards are presented in Table XI-2.  The new
source performance standards for metallurgical acid plants  are
presented in Table XI-3.
                             135
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-------
                       Table XI-2

          NSPS FOR THE PRIMARY MOLYBDENUM AND
                  RHENIUM SUBCATEGORY
 (a)  Molybdenum Sulfide Leaching

   Pollutant or        Maximum for       Maximum  for
 Pollutant Property	Any One Day	Monthly Average

  mg/kg  (Ib/million Ibs) of molybdenum sulfide leached

 Arsenic                   0.644              0.287
 Lead                      0.130              0.060
 Nickel                    0.255              0.171
 Selenium                  0.380              0.171
 Molybdenum                1.783              0.792
 Ammonia  (as N)           61.720             27.130
 Total suspended           6.945              5.556
  solids
 pH                     Within the range of  7.5 to 10.0
                                 at all times
(b)  Roaster S02 Scrubber

   Pollutant or        Maximum for       Maximum for
Pollutant Property	Any One Day	Monthly Average

  mg/kg (Ib/million Ibs) of molybdenum sulfide roasted

Arsenic                   2.334              1.041
Lead                      0.470              0.218
Nickel                    0.924              0.621
Selenium                  1.377              0.621
Molybdenum                6.464              2.871
Ammonia (as N)          223.800            98.390
Total suspended          25.180            20.140
  solids
pH                     Within the range of 7.5 to 10.0
                                 at all times
                               137
-------
                 Table XI-2 (Continued)

          NSPS FOR THE PRIMARY MOLYBDENUM AND
                  RHENIUM SUBCATEGORY
(c)  Molybdic Oxide Leachate

   Pollutant or        Maximum for       Maximum for
Pollutant Property	Any One Day	Monthly Average

      mg/kg (Ib/million Ibs) of ammonium molybdate
                        produced

Arsenic                  10.610             4.731
Lead                      1.989             0.923
Nickel                    3.906             2.628
Selenium                  5.824             2.628
Molybdenum               29.380            13.050
Ammonia (as N)        1,017.000           447.100
Total suspended         106.600            85.230
  solids
pH                     Within the range of 7.5 to 10.0
                                 at all times
(d)  Hydrogen Reduction Furnace Scrubber

   Pollutant or        Maximum for       Maximum for
Pollutant Property	Any One Day	Monthly Average

   mg/kg (Ib/million Ibs) of molybdenum metal powder
                        produced

Arsenic                   3.183             1.420
Lead                      0.641             0.298
Nickel                    1.260             0.847
Selenium                  1.878             0.847
Molybdenum                8.817             3.916
Ammonia (as N)          305.300           134.200
Total suspended          34.350            27.480
  solids
pH                     Within the range of 7.5 to 10.0
                                 at all times
                                38
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                 Table XI-2  (Continued)

          NSPS FOR THE PRIMARY MOLYBDENUM AND
                  RHENIUM SUBCATEGORY
(e)  Depleted Rhenium Scrubbing Solution

   Pollutant or        Maximum for       Maximum for
Pollutant Property	Any One Day	Monthly Average

  mg/kg (Ib/million Ibs) of molybdenum sulfide roasted

Arsenic                   0.995             0.444
Lead                      0.201             0.093
Nickel                    0.394             0.265
Selenium                  0.587             0.265
Molybdenum                2.757             1.224
Ammonia (as N)           94.440            41.960
Total suspended          10.740             8.592
  solids
pH                     Within the range of 7.5 to  10.0
                                 at all times
                              139
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                            Table XI-3

                NSPS FOR METALLURGICAL ACID PLANTS

Pollutant or pollutant property
NSPS
Maximum
for any
1 day
Maximum
for monthly
average
                                  (Mg/kg pounds per million
                                   pounds) of 100 pet sulfuric
                                   acid capacity
Arsenic	,
Cadm ium	
Copper	,
Lead	,
Zinc	
Total suspended solids,
pH	
 3.550
  .511
 3.269
  .715
 2.605
38.310
 1 .456
  .204
 1 .558
  .332
 1 .073
30.650
1 Within the range of 7.0 to 10.0 at all times
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            PRIMARY MOLYBDENUM AND  RHENIUM  SUBCATEGORY

                           SECTION  XII

                      PRETREATMENT  STANDARDS
Section 307(b) of the Act requires EPA  to promulgate  pretreatment
standards for existing sources  (PSES),  which  must  be  achieved
within three years of promulgation.   PSES are designed  to  prevent
the discharge of pollutants which pass  through,  interfere  with,
or are otherwise incompatible with the  operation of publicly
owned treatment works (POTW).   The Clean Water Act of 1977
requires pretreatment for pollutants, such as  heavy metals, that
limit POTW sludge management alternatives.  Section 307(c) of the
Act requires EPA to promulgate  pretreatment standards for  new
sources (PSNS) at the same time that  it promulgates NSPS.   New
indirect discharge facilities,  like new direct discharge facili-
ties, have the opportunity to incorporate the best available
demonstrated technologies, including  process  changes, in-plant
controls, and end-of-pipe treatment technologies,  and to use
plant site selection to ensure  adequate treatment  system instal-
lation.  Pretreatment standards  are to  be technology  based,
analogous to the best available  technology for removal  of  toxic
pollutants.

EPA is not proposing pretreatment standards for  existing sources
at this time because there are  currently no indirect  discharging
facilities in this subcategory.

This section describes the control and  treatment technologies for
pretreatment of process wastewaters from new  sources  in the pri-
mary molybdenum and rhenium subcategory.  Pretreatment  standards
for regulated pollutants are presented based  on  the selected
control and treatment technology.

TECHNICAL APPROACH TO PRETREATMENT

Before proposing pretreatment standards, the  Agency examines
whether the pollutants discharged by  the industry  pass  through
the POTW or interfere with the  POTW operation  or its  chosen
sludge disposal practices.  In  determining whether pollutants
pass through a well-operated POTW achieving secondary treatment,
the Agency compares the percentage of a pollutant  removed  by  POTW
with the percentage removed by  direct dischargers  applying the
best available technology economically achievable.  A pollutant
is deemed to pass through the POTW when the average percentage
removed nationwide by well-operated POTW meeting secondary
treatment requirements, is less  than  the percentage removed by
                               141
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direct dischargers complying with BAT effluent limitations guide-
lines for that pollutant.  (See generally, 46 FR at 9415-16
(January 28, 1981)).

This definition of pass-through satisfies two competing objec-
tives set by Congress:  (1) that standards for indirect dis-
chargers be equivalent to standards for direct dischargers while
at the same time, (2) that the treatment capability and perfor-
mance of the POTW be recognized and taken into account in regu-
lating the discharge of pollutants from indirect dischargers.

The Agency compares percentage removal rather than the mass or
concentration of pollutants discharged because the latter would
not take into account the mass of pollutants discharged to the
POTW from non-industrial sources or the dilution of the pollu-
tants in the POTW effluent to lower concentrations due to the
addition of large amounts of non-industrial wastewater.

PRETREATMENT STANDARDS FOR NEW SOURCES

Options for pretreatment of wastewaters from new sources are
based on increasing the effectiveness of end-of-pipe treatment
technologies.  All in-plant changes and applicable end-of-pipe
treatment processes have been discussed previously in Sections X
and XI.  The options for PSNS, therefore, are the same as the BAT
options discussed in Section X.  Similarly, the treatment tech-
nologies proposed for the expanded applicability of the metallur-
gical acid plants regulation to include pretreatment standards
for new source molybdenum acid plants are the same as those for
BAT.

A description of each option is presented in Section X, while a
more detailed discussion, including pollutants controlled by each
treatment process is presented in Section VII of the General
Development Document.

Treatment technologies considered for the PSNS options are:

OPTION A

     •  Preliminary treatment with ammonia steam stripping
        (where required)
     •  Chemical precipitation and sedimentation

OPTION B

     •  Preliminary treatment with ammonia steam stripping
        (where required)
     •  Chemical precipitation and sedimentation
     •  In-process flow reduction of hydrogen furnace reduction
        scrubber liquor
                              142
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OPTION C

     •  Preliminary treatment with ammonia  steam  stripping
        (where required)
     •  Chemical precipitation and sedimentation
     •  In-process flow reduction of hydrogen  furnace  reduction
        scrubber liquor
     •  Multimedia filtration

The promulgated treatment technologies  for  the metallurgical  acid
plants are presented below for PSNS:

     •  Preliminary treatment with sulfide  precipitation  and
        pressure filtration
     •  Chemical precipitation and sedimentation
     •  In-process flow reduction
     •  Multimedia filtration

PSNS OPTION SELECTION

We are proposing PSNS equal to NSPS and BAT for this subcategory.
It is necessary to propose PSNS to prevent  pass-through of
arsenic, lead, nickel, selenium, molybdenum and ammonia.   These
toxic pollutants are removed by a well-operated POTW achieving
secondary treatment at an average of 13 percent,  while the NSPS
and BAT level technology removes approximately 79 percent.

We are proposing to expand the applicability of the existing  PSNS
for metallurgical acid plants to include metallurgical acid
plants associated with primary molybdenum roasters.  It is  neces-
sary to propose PSNS to prevent pass-through of arsenic,  cadmium,
copper, lead and zinc.  These toxic pollutants are removed by a
well-operated POTW achieving secondary treatment  at an average  of
42 percent,  while BAT level technology removes approximately  83
percent.

We believe that the proposed PSNS are achievable, and  that they
are not a barrier to entry of new plants into this subcategory.

The wastewater discharge rates for PSNS are identical  to  the  BAT
discharge rates for each waste stream.  The PSNS  discharge rates
are shown in Table XII-1.

REGULATED POLLUTANT PARAMETERS

Pollutants selected for limitation,  in accordance with the
rationale of Sections VI and X,  are identical to  those selected
for limitation for BAT.  The Agency is considering limiting the
pollutant fluoride in this subcategory and  is soliciting  comments
from the industry.   Effluent limitations for fluoride would be
based on treatment effectiveness concentrations of 19.9 mg/1  for
                               143
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the monthly average and 35 mg/1 for the daily maximum.  A
complete discussion of fluoride may be found in  Section VII  of
the General Development Document under treatment performances of
additional pollutants.  The treatment effectiveness of fluoride
is based on data from the Electrical and Electronic Components
Phase II Category.

PRETREATMENT STANDARDS FOR NEW SOURCES

Pretreatment standards for new sources are based on the treatable
concentrations from the selected treatment technology, (Option
C), and the discharge rates determined in Section  X for BAT.  A
mass of pollutant per mass of product (mg/kg) allocation is  given
for each subdivision within the subcategory.  This pollutant
allocation is based on the product of the treatable concentration
from the proposed treatment (mg/1) and the production normalized
wastewater discharge rate (1/kkg).  The achievable treatment
concentrations for BAT are identical to those for  PSNS.  These
concentrations are listed in Table VII-19 of the General
Development Document. PSNS are presented in Table  XII-2.   PSNS
for metallurgical acid plants are presented in Table XII-3.
                              144
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                      Table XII-2

            PSNS FOR THE PRIMARY MOLYBDENUM
                AND RHENIUM SUBCATEGORY
(a)  Molybdenum Sulfide Leaching

   Pollutant or        Maximum for       Maximum for
Pollutant Property	Any One Day	Monthly Average

  mg/kg (Ib/million Ibs) of molybdenum sulfide leached

Arsenic                   0.644              0.287
Lead                      0.130              0.060
Nickel                    0.255              0.171
Selenium                  0.380              0.171
Molybdenum                1.783              0.792
Ammonia (as N)           61.720             27.130
(b)  Roaster S0.2 Scrubber

   Pollutant or        Maximum for       Maximum for
Pollutant Property	Any One Day	Monthly Average

  mg/kg (Ib/million Ibs) of molybdenum sulfide roasted

Arsenic                   2.334              1.041
Lead                      0.470              0.218
Nickel                    0.924              0.621
Selenium                  1.377              0.621
Molybdenum                6.464              2.871
Ammonia (as N)          223.800            98.390
(c)  Molybdic Oxide Leachate

   Pollutant or        Maximum for       Maximum for
Pollutant Property	Any One Day	Monthly Average

      mg/kg (Ib/million Ibs) of ammonium molybdate
                        produced

Arsenic                  10.610             4.731
Lead                      1.989             0.923
Nickel                    3.906             2.628
Selenium                  5.824             2.628
Molybdenum               29.380             13.050
Ammonia (as N)        1,017.000           447.100
                               146
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                Table XI1-2  (Continued)

            PSNS FOR THE  PRIMARY MOLYBDENUM
                AND RHENIUM  SUBCATEGORY
 (d)  Hydrogen Reduction Furnace Scrubber

   Pollutant or        Maximum for       Maximum  for
 Pollutant Property	Any One Day	Monthly Average

   mg/kg (Ib/million Ibs) of molybdenum metal powder
                        produced

Arsenic                   3.183              1.420
 Lead                      0.641              0.298
 Nickel                    1.260              0.847
 Selenium                  1.878              0.847
Molybdenum                8.817              3.916
Ammonia (as N)          305.300            134.200
(e)  Depleted Rhenium Scrubbing Solution

   Pollutant or        Maximum for       Maximum for
Pollutant Property	Any One Day     Monthly Average

  mg/kg (Ib/million Ibs) of molybdenum sulfide roasted

Arsenic                   .0.995             0.444
Lead                      0.201             0.093
Nickel                    0.394             0.265
Selenium                  0.587             0.265
Molybdenum                2.757             1.224
Ammonia (as N)           95.440            41.960
                               147
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           Table XII-3

PSNS FOR METALLURGICAL ACID PLANTS

Pollutant or pollutant property
PSNS
Maximum
for any
1 day
Maximum
for monthly
average
                  (Mg/kg pounds per million
                   pounds) of 100 percent
                   sulfuric acid capacity




Z inc 	

3.550
.51 1
3.269
.715
2.605

1 .456
.204
1 .558
.332
1 .073

               148
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            PRIMARY MOLYBDENUM AND RHENIUM SUBCATEGORY

                           SECTION XIII

          BEST CONVENTIONAL POLLUTANT CONTROL TECHNOLOGY
EPA is not proposing best conventional pollutant control
technology (BCT) limitations for the primary molybdenum and
rhenium subcategory at this time.
                               149
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