United States Effluent Guidelines Division EPA-440/1-84/019-b2
Environmental Protection WH-552 July 1984
Agency Washington, D.C. 20460 5unPl~?
Water and Waste Management
Development Proposed
Document for
Effluent Limitations
Guidelines and
Standards for the
Nonferrous Metals
Point Source Category
Phase II
Supplemental Development
Document For:
Secondary Mercury
-------
DEVELOPMENT DOCUMENT
for
EFFLUENT LIMITATIONS GUIDELINES AND STANDARDS
for the
NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY
PHASE II
Secondary Mercury Supplement
Jack E. Ravan
Assistant Administrator for Water
Edwin L. Johnson
Director
Office of Water Regulations and Standards
J o^h C^.iorn Street
n.cago, Uiinois 60604
Jeffery D. Denit, Director
Effluent Guidelines Division
Ernst P. Hall, P.E., Chief
Metals and Machinery Branch
James R. Berlow, P.E.
Technical Project Officer
July 1984
U.S. Environmental Protection Agency
Office of Water
Office of Water Regulations and Standards
Effluent Guidelines Division
Washington, D.C. 20460
-------
Agency
-------
SECONDARY MERCURY SUBCATEGORY
TABLE OF CONTENTS
Section Page
I SUMMARY AND CONCLUSIONS 1
II RECOMMENDATIONS 3
NSPS FOR THE SECONDARY MERCURY SUBCATEGORY ... 3
PSNS FOR THE SECONDARY MERCURY SUBCATEGORY ... 5
III INDUSTRY PROFILE 7
DESCRIPTION OF SECONDARY MERCURY PRODUCTION. . . 7
RAW MATERIALS 7
SEPARATION OF GROSS IMPURITIES 8
DISTILLATION 8
ACID WASHING 8
PROCESS WASTEWATER SOURCES 9
OTHER WASTEWATER SOURCES 9
AGE, PRODUCTION, AND PROCESS PROFILE 9
IV SUBCATEGORIZATION 15
FACTORS CONSIDERED IN SUBCATEGORIZATION 15
FACTORS CONSIDERED IN SUBDIVIDING THE
SECONDARY MERCURY SUBCATEGORY 16
OTHER FACTORS 17
PRODUCTION NORMALIZING PARAMETERS 17
V WATER USE AND WASTEWATER CHARACTERISTICS .... 19
WASTEWATER FLOW RATES 20
WASTEWATER CHARACTERISTICS DATA 21
DATA COLLECTION PORTFOLIO 21
FIELD SAMPLING DATA 21
WASTEWATER CHARACTERISTICS AND FLOWS BY
SUBDIVISION 22
SPENT BATTERY ELECTROLYTE. 22
ACID WASH AND RINSE WATER 22
FURNACE WET AIR POLLUTION CONTROL 22
-------
SECONDARY MERCURY SUBCATEGORY
TABLE OF CONTENTS (Continued)
Section
VI
VII
VIII
IX
X
Page
SELECTION OF POLLUTANT PARAMETERS 27
CONVENTIONAL POLLUTANT PARAMETERS 27
CONVENTIONAL POLLUTANT PARAMETERS SELECTED ... 27
TOXIC POLLUTANTS 28
TOXIC POLLUTANTS NEVER DETECTED 28
TOXIC POLLUTANTS NEVER FOUND ABOVE THEIR
ANALYTICAL QUANTIFICATION CONCENTRATION 31
TOXIC POLLUTANTS PRESENT BELOW CONCENTRATIONS
ACHIEVABLE BY TREATMENT 31
TOXIC POLLUTANTS SELECTED FOR FURTHER
CONSIDERATION IN ESTABLISHING LIMITATIONS
AND STANDARDS 32
CONTROL AND TREATMENT TECHNOLOGIES 33
CURRENT CONTROL AND TREATMENT PRACTICES 33
SPENT BATTERY ELECTROLYTE 33
ACID WASH AND RINSE WATER 34
FURNACE WET AIR POLLUTION CONTROL 34
CONTROL AND TREATMENT OPTIONS 34
OPTION A 34
OPTION C 34
COSTS, ENERGY, AND NONWATER QUALITY ASPECTS. . . 37
TREATMENT OPTIONS FOR NEW SOURCES 37
OPTION A 37
OPTION C 37
COST METHODOLOGY 38
NONWATER QUALITY ASPECTS 38
ENERGY REQUIREMENTS 38
SOLID WASTE 39
AIR POLLUTION 40
BEST PRACTICABLE CONTROL TECHNOLOGY CURRENTLY
AVAILABLE 43
BEST AVAILABLE TECHNOLOGY ECONOMICALLY
ACHIEVABLE 45
ii
-------
SECONDARY MERCURY SUBCATEGORY
TABLE OF CONTENTS (Continued)
Section
XI
XII
NEW SOURCE PERFORMANCE STANDARDS 47
TECHNICAL APPROACH TO NSPS 47
OPTION A 47
OPTION C 47
INDUSTRY COST AND POLLUTANT REMOVAL ESTIMATES. . 49
POLLUTANT REMOVAL ESTIMATES 49
COMPLIANCE COSTS 50
NSPS OPTION SELECTION 50
WASTEWATER DISCHARGE RATES 50
SPENT BATTERY ELECTROLYTE 51
ACID WASH AND RINSE WATER 51
FURNACE WET AIR POLLUTION CONTROL 51
REGULATED POLLUTANT PARAMETERS 51
NEW SOURCE PERFORMANCE STANDARDS 52
PRETREATMENT STANDARDS 59
TECHNICAL APPROACH TO fRETREATMENT 59
PRETREATMENT STANDARDS FOR NEW SOURCES 60
OPTION A 60
OPTION C 60
PSNS OPTION SELECTION 60
REGULATED POLLUTANT PARAMETERS 61
PRETREATMENT STANDARDS FOR NEW SOURCES 61
XIII
BEST CONVENTIONAL POLLUTANT CONTROL TECHNOLOGY
65
iii
-------
SECONDARY MERCURY SUBCATEGORY
LIST OF TABLES
Number Page
III-1
III-2
III-3
V-1
V-2
V-3
VIII-1
XI-1
XI-2
XI -3
XI-4
XII-1
XII-2
INITIAL OPERATING YEAR (RANGE) SUMMARY OF
PLANTS IN THE SECONDARY MERCURY SUBCATEGORY
BY DISCHARGE TYPE
PRODUCTION RANGES FOR THE SECONDARY MERCURY
SUBCATEGORY
SUMMARY OF SUBCATEGORY PROCESSES AND
ASSOCIATED WASTE STREAMS
WATER USE AND DISCHARGE RATES FOR
SPENT BATTERY ELECTROLYTE
WATER USE AND DISCHARGE RATES FOR
ACID WASH AND RINSE WATER
WATER USE AND DISCHARGE RATES FOR
FURNACE WET AIR POLLUTION CONTROL
COST OF COMPLIANCE FOR NEW SOURCE MODEL PLANTS
IN THE SECONDARY MERCURY SUBCATEGORY
POLLUTANT REMOVAL ESTIMATES FOR NEW SOURCE
MODEL PLANTS
COST OF COMPLIANCE FOR NEW SOURCE MODEL PLANTS
IN THE SECONDARY MERCURY SUBCATEGORY
NSPS WASTEWATER DISCHARGE RATES FOR THE
SECONDARY MERCURY SUBCATEGORY
NSPS FOR THE SECONDARY MERCURY SUBCATEGORY . . .
PSNS WASTEWATER DISCHARGE RATES FOR THE
SECONDARY MERCURY SUBCATEGORY
PSNS FOR THE SECONDARY MERCURY SUBCATEGORY . . .
10
11
12
24
25
26
41
53
54
55
56
62
63
-------
VI
-------
SECONDARY MERCURY SUBCATEGORY
LIST OF FIGURES
Number Page
III-1 SECONDARY MERCURY PRODUCTION PROCESS 13
IH-2 GEOGRAPHIC LOCATIONS OF THE SECONDARY
MERCURY SUBCATEGORY PLANTS 14
XI-1 NSPS TREATMENT SCHEME FOR OPTION A 57
XI-2 NSPS TREATMENT SCHEME FOR OPTION C 58
vii
-------
SECONDARY MERCURY SUBCATEGORY
SECTION I
SUMMARY AND CONCLUSIONS
Pursuant to Sections 301, 304, 306, 307, and 501 of the Clean
Water Act and the provisions of the Settlement Agreement in
Natural Resources Defense Council v. Train. 8 ERG 2120 (D.D.C.
1976) modified. 12 ERG 1833 (D.D.C. 1979), EPA has collected and
analyzed data for plants in the secondary mercury subcategory.
EPA has never proposed or promulgated effluent limitations or
standards for this subcategory. This document and the adminis-
trative record provide the technical basis for proposing pre-
treatment standards for new indirect dischargers (PSNS) and
standards of performance for new source direct dischargers
(NSPS).
The secondary mercury subcategory is comprised of four plants.
Two plants achieve zero discharge of process wastewater, and two
plants do not generate process wastewater.
EPA first studied the secondary mercury subcategory to determine
whether differences in raw materials, final products, manufactur-
ing processes, equipment, age and size of plants, or water usage,
required the development of separate effluent limitations and
standards for different segments of the subcategory. This
involved a detailed analysis of wastewater discharge and treated
effluent characteristics, including (1) the sources and volume of
water used, the processes used, and the sources of pollutants and
wastewaters in the plant; and (2) the constituents of waste-
waters, including toxic pollutants. As a result, three subdivi-
sions have been identified for this subcategory that warrant
separate effluent limitations. These include:
• Spent battery electrolyte,
• Acid wash and rinse water, and
• Furnace wet air pollution control.
EPA also identified several distinct control and treatment
technologies (both in-plant and end-of-pipe) applicable to the
secondary mercury subcategory. The Agency analyzed both histori-
cal and newly generated data on the performance of these technol-
ogies, including their nonwater quality environmental impacts and
air quality, solid waste generation, and energy requirements.
EPA also studied various flow reduction techniques reported in
the data collection portfolios (dcp) and plant visits.
-------
Engineering costs were prepared for each of the control and
treatment options considered for the subcategory. These costs
were then used by the Agency to estimate the impact of implement-
ing the various options on the subcategory. For each control and
treatment option that the Agency found to be most effective and
technically feasible in controlling the discharge of pollutants,
we estimated the number of potential closures, number of employ-
ees affected, and impact on price. These results are reported in
a separate document entitled "The Economic Impact Analysis of
Proposed Effluent Limitations Guidelines and Standards for the
Nonferrous Smelting and Refining Industry."
Existing performance of plants in the secondary mercury subcate-
gory is such that no discharge of process wastewater is presently
practiced at the plants in this industry. This is achieved by
100 percent recycle on-site or by contractor disposal of process
wastewater, or is a result of a production process that generates
no process water. Therefore, BPT, BAT, BCT, and PSES are not
applicable to this subcategory. BAT and PSES were recommended
for exclusion under Paragraph 8 of the Settlement Agreement. The
secondary mercury subcategory is regulated under New Source
Performance Standards and Pretreatment Standards for New Sources.
After examining the various treatment technologies, the Agency
has identified best demonstrated technology, which is the tech-
nical basis of NSPS, to represent the best existing technology in
the nonferrous metals manufacturing category. Metals removal
based on chemical precipitation, sedimentation, and multimedia
filtration technology is the basis for the NSPS limitations. In
selecting NSPS, EPA recognizes that new plants have the opportun-
ity to implement the best and most efficient manufacturing
processes and treatment technologies available.
PSES is not being proposed for this subcategory because there are
no existing indirect dischargers in the secondary mercury sub-
category. For PSNS, the Agency selected end-of-pipe treatment
techniques equivalent to NSPS.
Although the methodology for BCT has not yet been finalized, BCT
is not being proposed because there are no direct dischargers.
The mass limitations for NSPS and PSNS are presented in Section
II.
-------
SECONDARY MERCURY SUBCATEGORY
SECTION II
RECOMMENDATIONS
1. EPA has divided the secondary mercury subcategory into three
subdivisions for the purpose of effluent limitations and
standards. These subdivisions are:
(a) Spent battery electrolyte,
(b) Acid wash and rinse water, and
(c) Furnace wet air pollution control.
2. BPT is not being proposed because there are no direct
dischargers in the secondary mercury subcategory.
3. BAT is not being proposed because there are no direct
dischargers in the secondary mercury subcategory.
4. NSPS are proposed based on the performance achievable by the
application of chemical precipitation, sedimentation, and
multimedia filtration technology. The following effluent
standards are proposed for new sources:
NSPS FOR THE SECONDARY MERCURY SUBCATEGORY
(a) Spent Battery Electrolyte
Pollutant or Maximum for Maximum for
Pollutant Property Any One Day Monthly Average
mg/kg (Ib/million Ibs) of mercury produced from
batteries
Lead 0.030 0.014
Mercury 0.016 0.006
Total suspended 1.590 1.272
solids
pH Within the range of 7.5 to 10.0
at all times
-------
NSPS FOR THE SECONDARY MERCURY SUBCATEGORY
(b) Acid Wash and Rinse Water
Pollutant or Maximum for Maximum for
Pollutant Property Any One Day Monthly Average
mg/kg (Ib/million Ibs) of mercury washed and rinsed
Lead 0.00056 0.00026
Mercury 0.00030 0.00012
Total suspended 0.030 0.024
solids
pH Within the range of 7.5 to 10.0
at all times
NSPS FOR THE SECONDARY MERCURY SUBCATEGORY
(c) Furnace Wet Air Pollution Control
Pollutant or Maximum for Maximum for
Pollutant Property Any One Day Monthly Average
mg/kg (Ib/million Ibs) of mercury processed through
furnace
Lead 0.000 0.000
Mercury 0.000 0.000
Total suspended 0.000 0.000
solids
pH Within the range of 7.5 to 10.0
at all times
5. PSES are not being proposed because there are no indirect
dischargers in the secondary mercury subcategory.
6. PSNS are proposed based on the performance achievable by the
application of chemical precipitation, sedimentation, and
multimedia filtration technology. The following
pretreatment standards are proposed for new sources:
-------
PSNS FOR THE SECONDARY MERCURY SUBCATEGORY
(a) Spent Battery Electrolyte
Pollutant or Maximum for Maximum for
Pollutant Property Any One Day Monthly Average
mg/kg (Ib/million Ibs) of mercury produced from
batteries
Lead 0.030 0.014
Mercury 0.016 0.006
PSNS FOR THE SECONDARY MERCURY SUBCATEGORY
(b) Acid Wash and Rinse Water
Pollutant or Maximum for Maximum for
Pollutant Property Any One Day Monthly Average
mg/kg (Ib/million Ibs) of mercury washed and rinsed
Lead 0.00056 0.00026
Mercury 0.00030 0.00012
PSNS FOR THE SECONDARY MERCURY SUBCATEGORY
(c) Furnace Wet Air Pollution Control
Pollutant or Maximum for Maximum for
Pollutant Property Any One Day Monthly Average
mg/kg (Ib/million Ibs) of mercury processed through
furnace
Lead 0.000 0.000
Mercury 0.000 0.000
7. BCT is not being proposed for the secondary mercury
subcategory at this time.
-------
6
-------
SECONDARY MERCURY SUBCATEGORY
SECTION III
INDUSTRY PROFILE
This section of the secondary mercury supplement describes the
raw materials and processes used in producing secondary mercury
and presents a profile of the secondary mercury plants identified
in this study. For a discussion of the purpose, authority, and
methodology for this study, and a general description of the non-
ferrous metals manufacturing category, refer to Section III of
the General Development Document.
Mercury is used in numerous agricultural, chemical and electrical
applications. Mercury is used extensively in the chemical indus-
try, particularly in the production of chlorine and caustic soda.
Mercury compounds are also used extensively in paints and as
catalysts. Agricultural uses of mercury include germicides for
seed protection and weed control, and fungicidal fruit sprays.
Electrical applications include low-pressure and high-pressure
mercury vapor lamps, power control switches, and dry-cell
batteries. Other uses are in barometers, thermometers, as a
vibration damper, and as a coolant. Mercury produced from
secondary sources is used in many applications, such as those
described above.
DESCRIPTION OF SECONDARY MERCURY PRODUCTION
The production of secondary mercury can be divided into three
distinct stages: separation of gross impurities, distillation,
and acid washing. The actual processes used in each stage vary
with the type and purity of the raw material used. The secondary
mercury production process is presented schematically in Figure
III-1 and is described below.
RAW MATERIALS
Mercury can be reclaimed from a variety of raw materials, includ-
ing thermometers, switches, filters, controls, zinc and silver
amalgams, mercuric oxide battery.cells, and other types of scrap.
Secondary mercury annually supplies the United States with
approximately 20 percent of domestic requirements. Several
plants refining secondary mercury also refine prime virgin
mercury. Although prime virgin mercury can be considered to be a
primary raw material, its refining is included with secondary
mercury, because it is refined on-site with secondary mercury
using the same equipment and production processes.
-------
SEPARATION OF GROSS IMPURITIES
Depending on the type of raw material being processed, gross
impurities, such as glass from mercury thermometers, or spent
electrolyte from mercuric oxide battery cells, may have to be
separated from the mercury. The separation of gross impuri-
ties must occur prior to distilling the mercury. Raw materials
such as thermometers, switches, filters, controls, and zinc and
silver amalgams may be separated from their gross impurities by
roasting in a furnace. The mercury is separated from impurities
by vaporizing it, and then recovering mercury by condensation.
The nonvolatilized solids are removed from the furnace after all
the mercury has been removed. A water scrubber may be used to
control air emissions from the mercury furnace-condenser, and the
scrubber may have a discharge from it.
Before mercury can be recovered from mercuric oxide battery
cells, the battery electrolyte must be removed. On a small
scale, this is most likely accomplished by manually draining the
spent electrolyte from each cell. Spent electrolyte removed in
this step is a waste stream.
DISTILLATION
Mercury distillation columns, also known as retorts, stills, or
kettles, are used to produce high-purity mercury. No waste-
water is generated by this process. A typical distillation pro-
cess consists of charging raw, impure mercury into the bottom of
a still and heating the charge to a prescribed temperature, some-
what less than the boiling point of mercury, 356.9 C. While
heating the charge, air may be bubbled through the still in order
to oxidize metallic impurities, such as lead, zinc, cadmium, cop-
per or tin. When the charge reaches the critical temperature,
the mercury begins to vaporize, and the mercury is recovered in
an overhead, water cooled condensing system. Mercury distilla-
tion may be run batchwise or continuously, and in both cases it
can be considered a dry process. None of the water used in the
condensing coils contacts the mercury.
Multiple distillation units may be operated in series to produce
very high purity (approximately 99.999999 percent) mercury. Like
the single distillation process, no wastewater is generated by
multiple distillation units.
ACID WASHING
Another method for further purifying mercury is acid washing and
rinsing. In this method, a small amount of dilute nitric acid is
used to wash the distilled mercury product, and then a small
amount of distilled water is used to wash the residual acid from
the mercury product. Mercury of 99.9 percent purity can be
8
-------
produced in this manner. The acid wash and rinse water may be
discharged from this process as a waste stream.
PROCESS WASTEWATER SOURCES
Although a variety of processes are involved in secondary mercury
production, the process wastewater sources can be subdivided as
follows:
1. Spent battery electrolyte,
2. Acid wash and rinse water, and
3. Furnace wet air pollution control.
OTHER WASTEWATER SOURCES
There are other waste streams associated with the secondary
mercury subcategory. These waste streams include, but are not
limited to:
1. Stormwater runoff,
2. Maintenance and cleanup water, and
3. Noncontact cooling water.
These waste streams are not considered as a part of this rulemak-
ing. EPA believes that the flows and pollutant loadings associ-
ated with these waste streams are insignificant relative to the
waste streams selected, or are best handled by the appropriate
permit authority on a case-by-case basis under authority of
Section 403 of the Clean Water Act.
AGE, PRODUCTION, AND PROCESS PROFILE
Figure III-2 shows the locations of the four secondary mercury
plants operating in the United States. Two of the four plants
are located near the industrial centers of the Northeast, one is
in Illinois, and one in California.
Table III-1 shows the relative age and discharge status of the
mercury plants and illustrates that all the plants were built
after World War II. The average plant age is 30 years old. From
Table II1-2, it can be seen that two plants produce between 50
and 100 tons per year of metal, while one plant produces less
than 25 tons per year. Mean production is about 55 tons per
year.
Table III-3 provides a summary of the number of plants generating
wastewater for the waste streams associated with various piu<-es-
ses and the number of plants with the process.
-------
Table III-1
INITIAL OPERATING YEAR (RANGE) SUMMARY OF PLANTS
IN THE SECONDARY MERCURY SUBCATEGORY BY DISCHARGE TYPE
Initial Operating Year (Range)
(Plant Age in Years)
Type
of Plant
Direct
Indirect
Zero
Dry
TOTAL
1982-
1968
(0-15)
0
0
0
0
1967-
1958
(16-25)
0
0
0
1
0
1957-
1948
(26-35)
0
0
Total
0
0
2
2*
4
*0ne plant did not report initial operating year
10
-------
Table III-2
PRODUCTION RANGES FOR THE SECONDARY MERCURY SUBCATEGORY
Type of Plant
Direct
Indirect
Zero
Dry
Mercury Production Range for 1982
0-25
(tons/yr)
0
0
1
0
25-50
(tons/yr)
0
0
0
0
50-100
(tons/yr)
0
0
1
1
Total Number
of Plants
0
0
2
•
2*
4
*0ne plant did not report mercury production,
-------
Table III-3
SUMMARY OF SUBCATEGORY PROCESSES AND ASSOCIATED
WASTE STREAMS
Number
Number of of Plants
Plants With Reporting
Process or Generation
Process or Waste Stream Waste Stream of Wastewater*
Spent battery electrolyte 1 1
Furnace wet air pollution control 1 0
Distillation 4 0
Acid wash and rinse water 1 1
*Through reuse or evaporation practices, a plant may "generate"
a wastewater from a particular process but not discharge it.
12
-------
"«
13
-------
CO
H
PQ
P
CO
Q) O
}-< O
^ W
00 CO
•H
14
-------
SECONDARY MERCURY SUBCATEGORY
SECTION IV
SUBCATEGORIZATION
As discussed in Section IV of the General Development Document,
the nonferrbus metals manufacturing category has been subcate-
gorized to take into account pertinent industry characteristics,
manufacturing process variations, and a number of other factors
which affect the ability of the facilities to achieve effluent
limitations. This section summarizes the factors considered
during the designation of the secondary mercury subcategory and
its related subdivisions. Production normalizing parameters for
each subdivision will also be discussed.
FACTORS CONSIDERED IN SUBCATEGORIZATION
The following factors were evaluated for use in subcategorizing
the nonferrous metals manufacturing category:
1. Metal products, co-products, and by-products;
2. Raw materials;
3. Manufacturing processes;
4. Product form;
5. Plant location;
6. Plant age;
7. Plant size;
8. Air pollution control methods;
9. Meteorological conditions;
10. Treatment costs;
11. Nonwater quality aspects;
12. Number of employees;
13. Total energy requirements; and
14. Unique plant characteristics.
Evaluation of all factors that could warrant subcategorization
resulted in- the designation of the secondary mercury subcategory.
Three factors were particularly important in establishing these
classifications: the type of metal produced, the nature of the
raw material used, and the manufacturing processes involved.
In Section IV of the General Development Document, each of these
factors is described, and the rationale for selecting metal
product, manufacturing process, and raw materials as the princi-
pal factors used for subcategorization is discussed. On this
basis, the nonferrous metals manufacturing category (phase II)
was divided into 21 subcategories, one of them being secondary
mercury.
15
-------
FACTORS CONSIDERED IN SUBDIVIDING THE SECONDARY MERCURY SUBCATE-
GQRY
The factors listed previously were each evaluated when consider-
ing subdivision of the secondary mercury subcategory. In the
discussion that follows, the factors will be described as they
pertain to this particular subcategory.
The rationale for considering further subdivision of the second-
ary mercury subcategory is based primarily on differences in the
production processes and raw materials used. Within this subcat-
egary, a number of different operations are performed, which may
or may not have a water use or discharge, and which may require
the establishment of separate effluent limitations. While
secondary mercury is still considered a single subcategory, a
more thorough examination of the production processes has
illustrated the need for limitations and standards based on
specific flow allowances for the following subdivisions:
1. Spent battery electrolyte,
2. Acid wash and rinse water, and
3. Furnace wet air pollution control.
These subdivisions follow directly from differences within the
three distinct production stages of secondary mercury: separa-
tion of gross impurities, distillation, and additional purifica-
tion. A secondary mercury plant may have one, two, or all three
of these production stages.
Separation of gross impurities such as spent battery electrolyte
or glass from thermometers gives rise to the first and third
subdivisions: spent battery electrolyte and furnace wet air pol-
lution control. A plant which recovers mercury from mercuric
oxide battery cells must first drain the spent electrolyte from
the cells. This wastewater may be discharged. A plant which
recovers mercury from recycled thermometers, switches, filters,
and amalgams may remove the mercury from the unwanted solids by
vaporizing mercury in a furnace. After condensing the product
mercury, the air emissions may be controlled with a scrubber.
The furnace scrubber may have a discharge, and this creates the
need for the third subdivision.
Additional purification of the mercury product gives rise to the
second subdivision: acid wash and rinse water. After distilling
the mercury, it may be washed with acid and rinsed with water to
increase its purity. The acid wash and rinse water may be dis-
charged as a waste stream.
16
-------
OTHER FACTORS
The other factors considered in this evaluation either support
the establishment of the three subdivisions or were shown to be
inappropriate bases for subdivision. Air pollution control
methods, treatment costs, and total energy requirements are func-
tions of the selected subcategorization factors--metal product,
raw materials, and production processes. Therefore, they are not
independent factors and do not affect the subcategorization which
has been applied. As discussed in Section IV of the General
Development Document, certain other factors, such as plant age,
plant size, and the number of employees, were also evaluated and
determined to be inappropriate for use as bases for subdivision
of nonferrous metals plants.
PRODUCTION NORMALIZING PARAMETERS
As discussed previously, the effluent limitations and standards
developed in this document establish mass limitations on the dis-
charge of specific pollutant parameters. To allow these regula-
tions to be applied to plants with various production capacities,
the mass of pollutant discharged must be related to a unit of
production. This factor is known as the production normalizing
parameter (PNP).
In general, for each production process which has a wastewater
associated with it, the actual mass of mercury product or inter-
mediate produced will be used as the PNP. Thus, the PNPs for the
three subdivisions are as follows:
Subdivision PNP
1. Spent battery electrolyte mercury produced from
batteries
2. Acid wash and rinse water mercury washed and rinsed
3. Furnace wet air pollution mercury processed through
control furnace
Other PNPs were considered. The use of production capacity in-
stead of actual production was eliminated from consideration be-
cause the mass of the pollutant produced is more a function of
true production than of installed capacity.
17
-------
SECONDARY MERCURY SUBCATEGORY
SECTION V
WATER USE AND WASTEWATER CHARACTERISTICS
This section describes the characteristics of the wastewaters
associated with the secondary mercury subcategory. Water use and
discharge rates are explained and then summarized in tables at
the end of this section. Data used to characterize the waste-
waters are presented. Finally, the specific source, water use
and discharge flows, and wastewater characteristics for each
separate wastewater source are discussed.
Section V of the General Development Document contains a detailed
description of the data sources and methods of analysis used to
characterize wastewater from the nonferrous metals manufacturing
category. To summarize this information briefly, two principal
data sources were used; data collection portfolios (dcp) and
field sampling results. Data collection portfolios contain
information regarding wastewater flows and production levels.
In order to quantify the pollutant discharge from secondary
mercury plants, the levels of toxic pollutants in the wastewaters
must be known. Since field sampling was not performed at any
plants in the secondary mercury subcategory, analytical data,
presented in Section V of the supplement for the primary precious
metals and mercury subcategory, were transferred from a primary
mercury plant to characterize wastewater in the secondary mercury
industry. A complete list of the pollutants considered and a
summary of the techniques used in sampling and laboratory analy-
ses are included in Section V of the General Development Docu-
ment. In general, the samples were analyzed for two classes of
pollutants (including 13 of the 126 toxic pollutants): toxic
metal pollutants and criteria pollutants (which includes both
conventional and nonconventional pollutants). Because the
analytical standard for TCDD was judged to be too hazardous to be
made generally available, samples were never analyzed for this
pollutant. Samples were also never analyzed for asbestos or
cyanide. There is no reason to expect that TCDD, asbestos, or
cyanide would be present in secondary mercury wastewater.
As described in Section IV of this supplement, the secondary
mercury subcategory has been split into three subdivisions or
wastewater sources, so that the proposed regulation contains mass
discharge limitations and standards for three unit processes
discharging process wastewater. Differences in the wastewater
characteristics associated with these subdivisions are to be
19
-------
expected. For this reason, wastewater streams corresponding to
each subdivision are addressed separately in the discussions that
follow. These wastewater sources are:
1. Spent battery electrolyte,
2. Acid wash and rinse water, and
3. Furnace wet air pollution control.
WASTEWATER FLOW RATES
Data supplied by dcp responses were evaluated, and two flow-to-
production ratios, water use and wastewater discharge flow, were
calculated for each stream. The two ratios are differentiated by
the flow value used in calculation. Water use is defined as the
volume of water or other fluid required for a given process per
mass of mercury product and is therefore based on the sum of
recycle and make-up flows to a given process. Wastewater flow
discharged after pretreatment or recycle (if these are present)
is used in calculating the production normalized flow--the volume
of wastewater discharged from a given process to further treat-
ment, disposal, or discharge per mass of mercury produced. Dif-
ferences between the water use and wastewater flows associated
with a given stream result from recycle, evaporation, and carry-
over on the product. The production values used in calculation
correspond to the production normalizing parameter, PNP, assigned
to each stream, as outlined in Section IV. As an example, acid
wash and rinse water flow is related to the amount of mercury
washed and rinsed. As such, the discharge rate is expressed in
liters of acid wash and rinse water per metric ton of mercury
washed and rinsed (gallons of acid wash and rinse water per ton
of mercury washed and rinsed).
The production normalized discharge flows were compiled and sta-
tistically analyzed by stream type. These production normalized
water use and discharge flows are presented by subdivision in
Tables V-1 through V-3 at the end of this section. Where appro-
priate, an attempt was made to identify factors that could
account for variations in water use and discharge rates. These
variations are discussed later in this section by subdivision. A
similar analysis of factors affecting the wastewater flows is
presented in Sections XI and XII where representative NSPS and
pretreatment flows are selected for use in calculating the
effluent limitations.
The water use and discharge rates shown do not include nonprocess
wastewater, such as rainfall runoff and noncontact cooling water.
20
-------
WASTEWATER CHARACTERISTICS DATA
Data used to characterize the various wastewaters associated with
secondary mercury production come from two sources--data collec-
tion portfolios and analytical data from field sampling trips.
DATA COLLECTION PORTFOLIOS
In the data collection portfolios, the mercury plants that
generate wastewater were asked to specify the presence of toxic
pollutants in their wastewater. No plants indicated that any
toxic organic pollutants were present. However, one of the two
plants stated that they either knew toxic metals to be present or
they believed the metals to be present. The responses for the
metals and cyanide are summarized below:
Known Believed
Pollutant Present Present
Antimony 0 0
Arsenic 0 0
Beryllium 0 0
Cadmium 0 0
Chromium 0 0
Copper 0 0
Cyanide 0 0
Lead 0 0
Mercury 1 1
Nickel 0 0
Selenium 0 0
Silver 0 0
Thallium 0 0
Zinc 0 0
FIELD SAMPLING DATA
In order to quantify the concentrations of pollutants present in
wastewater from secondary mercury plants, wastewater samples were
collected at one primary mercury plant, which roasts mercury ore
to produce mercury metal. Analytical data from the primary
mercury plant are presented in the supplement for the primary
precious metals and mercury subcategory. Primary mercury and
secondary mercury field sampling data are expected to show simi-
lar characteristics because of similarities in raw materials and
production processes. Both plants roast or distill a mercury-
containing raw material and use wet scrubbers to control emis-
sions, and also wash their product to increase its purity.
21
-------
WASTEWATER CHARACTERISTICS AND FLOWS BY SUBDIVISION
Since secondary mercury production involves three principal
sources of wastewater and each has potentially different charac-
teristics and flows, the wastewater characteristics and discharge
rates corresponding to each subdivision will be described sepa-
rately. A brief description of why the associated production
processes generate a wastewater and explanations for variations
of water use within each subdivision will also be discussed.
SPENT BATTERY ELECTROLYTE
One plant recovers mercury from mercuric oxide battery cells.
The first step in this recovery is to drain the spent electrolyte
from the cells. Spent battery electrolyte may be discharged as a
waste stream. Production normalized water use and discharge
rates for this waste stream are shown in Table V-1, in liters per
metric ton of mercury produced from batteries. This subdivision
is similar to spent battery electrolyte from lead batteries (see
the battery cracking subdivision of the secondary lead supplement
in nonferrous phase I); however, secondary mercury spent electro-
lyte is not expected to have similar pollutant characteristics
nor similar production normalized flows.
Although spent battery electrolyte was not sampled, wastewater
from the primary mercury industry should have similar character-
istics to this waste stream. Spent battery electrolyte should
contain treatable concentrations of toxic metals, total suspended
solids, and exhibit a low pH.
ACID WASH AND RINSE WATER
After recovering mercury in a distillation system, the product
may be washed with dilute nitric acid and rinsed with distilled
water in order to further purify it. Acid washing and water
rinsing produces a highrpurity (99.9 percent) mercury product,
and also generates a wastewater stream which may be discharged.
The production normalized water use and discharge rates for acid
wash and rinse water are given in Table V-2, in liters per metric
ton of mercury washed and rinsed.
Although acid wash and rinse water was not sampled, data from the
primary mercury industry should be similar to this waste stream.
Acid wash and rinse water should contain treatable concentrations
of toxic metals, total suspended solids, and exhibit a low pH.
FURNACE WET AIR POLLUTION CONTROL
One plant recovers mercury from sources such as thermometers,
switches, contacts, and amalgams by heating the raw materials in
22
-------
a furnace in order to vaporize the mercury. After condensing the
mercury product, air emissions from the furnace may be controlled
with a wet scrubber. The furnace scrubber may have a discharge
associated with it. Water use and discharge rates for furnace
wet air pollution control are presented in Table V-3. Only one
plant has this process and operates its scrubber at 100 percent
recycle.
.23
-------
Table V-1
WATER USE AND DISCHARGE RATES FOR
SPENT BATTERY ELECTROLYTE
(1/kkg of mercury produced from batteries)
Production
Production Normalized
Percent Normalized Discharge
Plant Code Recycle Water Use Flow
1161 0 106 106
24
-------
Table V-2
WATER USE AND DISCHARGE RATES FOR
ACID WASH AND RINSE WATER
(1/kkg of mercury washed and rinsed)
Production
Production Normalized
Percent Normalized Discharge
Plant Code Recycle Water Use Flow
1161 0 2.0 2.0
25
-------
Table V-3
WATER USE AND DISCHARGE RATES FOR
FURNACE WET AIR POLLUTION CONTROL
(1/kkg of mercury processed through furnace)
Production
Production Normalized
Percent Normalized Discharge
Plant Code Recycle Water Use Flow
1011 100 Unknown 0
26
-------
SECONDARY MERCURY SUBCATEGORY
SECTION VI
SELECTION OF POLLUTANT PARAMETERS
Although wastewater from secondary mercury facilities was not
sampled, it should have similar characteristics to wastewater
from a primary mercury facility. Analytical data from a primary
mercury plant are presented in Section V of the supplement for
primary precious metals and mercury. This section examines that
data and discusses the selection or exclusion of pollutants for
potential limitation.
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 pollutants for effluent limitations.
Also described is the analysis that was performed to select or
exclude toxic pollutants for further consideration for limita-
tions and standards. Pollutants will be considered for limita-
tion if they are present in concentrations treatable by the
technologies considered in this analysis. The treatable concen-
trations 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 POLLUTANT PARAMETERS
This study examined samples for the secondary mercury subcategory
for three conventional pollutant parameters (oil and grease,
total suspended solids, and pH).
CONVENTIONAL POLLUTANT PARAMETERS SELECTED
The conventional pollutants or pollutant parameters selected for
limitation in this subcategory are:
27
-------
total suspended solids (TSS)
pH
None of the nonconventional pollutants or pollutant parameters
are selected for limitation in this subcategory.
TSS are expected to be present in secondary mercury wastewaters
in concentrations exceeding that achievable by identified treat-
ment technologies (2.6 mg/1). In the primary mercury plant's
wastewater, TSS concentrations ranged from 4 mg/1 to 3,700 mg/1.
Furthermore, 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 dis-
charged. Meeting a limitation on total suspended solids helps
ensure that removal of'these precipitated toxic metals has been
effective. For these reasons, total suspended solids are
selected for limitation in this subcategory.
Spent battery electrolyte and acid wash and rinse water are
expected to have pH values less than pH 7.5, which is outside the
pH 7.5 to 10 range considered desirable for discharge to receiv-
ing waters. Four of the six primary mercury wastewater samples
had pH values between 2.3 and 2.6. Many deleterious effects are
caused by extreme pH values or rapid changes in pH. Also, effec-
tive removal of toxic metals by precipitation 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
Raw wastewater from secondary mercury plants was not sampled,
however, raw wastewater samples from the primary mercury industry
should be representative of the wastewater from secondary mercury
plants. These data provide the basis for the categorization of
specific pollutants, as discussed below. Treatment plant samples
were not considered in the frequency count.
TOXIC POLLUTANTS NEVER DETECTED
The toxic pollutants listed below were not detected or not
analyzed for in any raw wastewater samples; therefore, they are
not selected for consideration in establishing limitations.
1. acenaphthene*
2. acrolein*
3. acrylonitrile*
4. benzene*
5. benzidine*
6, carbon tetrachloride (tetrachloromethane)*
28
-------
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 (trichloromethane)*
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*
44. methylene chloride (dichloromethane)*
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*
29
-------
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)fluoranthane (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)*
94. 4,4'-DDD(p,p'TDE)*
95. Alpha-endosulfan*
96. Beta-endosulfan*
97. endosulfan sulfate*
98. endrin*
99. endrin aldehyde*
100. heptachlor*
101. heptachlor epoxide*
102. Alpha-BHC*
103. Beta-BHC *
104. Gamma-BHC (lindane)*
105. Delta-BHC*
106. PCB-1242 (Arochlor 1242)*
30
-------
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 (Fibrous)
121. cyanide (Total)*
129. 2,3,7,8-tetra chlorodibenzo-p-dioxin (TCDD)
*We did not analyze for these pollutants in samples of raw
wastewater from this subcategory. These pollutants are not
believed to be present based on the Agency's best engineering
judgement which includes consideration of raw materials and
process operations.
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; therefore, they are not selected for consideration in
establishing limitations.
114. antimony
117. beryllium
119. chromium (Total)
120. copper
124. nickel
125. selenium
126. silver
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 above concentrations considered achievable by
existing or available treatment technologies. These pollutants
are discussed individually following the list.
115. arsenic
118. cadmium
Arsenic was detected above the quantification concentration but
below the treatable concentration in one sample analyzed. The
sample contained 0.32 mg/1 arsenic which is below the 0.34 mg/1
treatable concentration. Therefore, arsenic is not selected for
limitation.
31
-------
Cadmium was detected above the quantification concentration in
one sample analyzed. The sample indicated a cadmium concentra-
tion, of 0.04 mg/1. This is below the 0.049 mg/1 treatable
concentration, thus cadmium is not selected for limitation.
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 consider-
ation for limitation are each discussed following the list.
122. lead
123. mercury
127. thallium
128. zinc
Lead was detected above its treatability of 0.08 mg/1 in one sam-
ple. This sample indicated a lead concentration of 22 mg/1.
Lead is also expected to be present in wastewaters from this
industry because it is a contaminant of the raw materials used
for mercury recovery. Thus, lead is selected for further consid-
eration for limitation.
Mercury was present above treatable concentrations in the waste-
water from this industry. One sample showed a concentration of
360 mg/1 of mercury. In the recovery of secondary mercury, mer-
cury contacts various aqueous streams in which it is partially
soluble. For these reasons, mercury is selected for further
consideration for limitation.
Thallium was detected above its treatability of 0.34 mg/1 in one
sample. This sample indicated 0.61 mg/1 of thallium. Thus,
thallium is selected for consideration for limitation.
Zinc was detected above treatable concentrations in one sample
indicating 0.73 mg/1. Treatability for zinc is 0.23 mg/1. Zinc
is also expected to be present in wastewaters from this industry
because it is present in batteries which are used as raw mate-
rials for secondary mercury recovery. Therefore, zinc is
selected for further consideration for limitation.
32
-------
SECONDARY MERCURY SUBCATEGORY
SECTION VII
CONTROL AND TREATMENT TECHNOLOGIES
The preceding sections of this supplement discussed the sources,
flows, and characteristics of the wastewaters from secondary
mercury plants. This section summarizes the description of these
wastewaters and indicates the treatment technologies which are
currently practiced in the secondary mercury subcategory for each
waste stream. Secondly, this section presents the control and
treatment technology options which were examined by the Agency
for possible application to the secondary mercury subcategory.
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 being applied to each of the
sources generating wastewater in this subcategory. As discussed
in Section V, wastewater associated with the secondary mercury
subcategory is characterized by the presence of the toxic metal
pollutants and suspended solids. This analysis is supported by
the raw (untreated) wastewater data presented for primary mercury
sources as well as raw materials and production processes as
shown in Section VI. 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 economic scale and
in some instances to combine streams of different alkalinity to
reduce treatment chemical requirements. No plants in this
subcategory currently treat their wastewater. One plant employs
contractor disposal of their wastewater, and one plant employs
100 percent recycle of scrubber liquor. The options selected for
consideration for NSPS and pretreatment based on combined treat-
ment of these compatible waste streams will be summarized toward
the end of this section.
SPENT BATTERY ELECTROLYTE
Mercury may be reclaimed from recycled mercuric oxide battery
cells. Before distilling the mercury contained in the battery,
the spent electrolyte must be drained. One plant processes
recycled batteries, and has their sp.ent battery electrolyte
hauled away by an approved contractor.
33
-------
ACID WASH AND RINSE WATER
After recovering mercury from recycled batteries by distillation,
the mercury product may be further purified. Purification is
effected by washing the mercury with dilute nitric acid, and then
rinsing it with water. One plant generates an acid wash and
rinse water waste stream in this manner, and disposes of it by
having a contractor haul it away.
FURNACE WET AIR POLLUTION CONTROL
Mercury may be reclaimed from scrap such as thermometers,
switches, filters, controls, amalgams, and soil samples by
vaporizing the mercury in a furnace. After recovering the
vaporized mercury by condensation, the air emissions from the
furnace may be controlled with a wet scrubber. One plant
practices furnace wet air pollution control, and recycles 100
percent of the scrubber liquor. There is no liquid effluent from
this process.
CONTROL AND TREATMENT OPTIONS
The Agency examined two control and treatment technology options
that are applicable to the secondary mercury subcategory. The
options selected for evaluation represent a combination of
end-of-pipe treatment technologies.
OPTION A
Option A for the secondary mercury subcategory requires control
and treatment technologies to reduce the discharge of wastewater
pollutant mass.
The Option A treatment scheme consists of chemical precipitation
and sedimentation technology. Specifically, lime or some other
alkaline compound is used to precipitate toxic metal ions as
metal hydroxides. The metal hydroxides and suspended solids
settle out and the sludge is collected. Vacuum filtration is
used to dewater sludge.
OPTION C
Option C for the secondary mercury subcategory consists of all
control and treatment requirements of Option A (chemical precip-
itation and sedimentation) plus multimedia filtration technology
added at the end of the Option A treatment scheme. Multimedia
filtration is used to remove suspended solids, including precipi-
tates 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
34
-------
filters or pressure filters would perform satisfactorily. The
addition of filters also provides consistent removal during
periods of time in which there are rapid increases in flows or
loadings of pollutants to the treatment system.
35
-------
36
-------
SECONDARY MERCURY SUBCATEGORY
SECTION VIII
COSTS, ENERGY, AND NONWATER QUALITY ASPECTS
This section presents a summary of compliance costs for the
secondary mercury subcategory and a description of the treatment
options and subcategory-specific assumptions used to develop
these estimates. Together with the estimated pollutant removal
performance presented in Section XI 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.
As there are no existing direct or indirect dischargers in this
subcategory, plant-by-plant compliance cost estimation was not
appropriate. Rather, based on analysis of the production sam-
pling data from plants presently in the subcategory, compliance
costs for new source model plants were estimated for each of the
considered treatment options.
In addition, this section addresses nonwater quality environ-
mental impacts of wastewater treatment and control alternatives,
including air pollution, solid wastes, and energy requirements,
which are specific to the secondary mercury subcategory.
TREATMENT OPTIONS FOR NEW SOURCES
As discussed in Section VII, two treatment options have been
developed and considered in proposing standards for the secondary
mercury subcategory These options are summarized below and
schematically presented in Figures XI-1 and XI-2.
OPTION A
The Option A treatment scheme consists of chemical precipitation
and sedimentation technology.
OPTION C
Option C for the secondary mercury subcategory consists of all
control and treatment requirements of Option A (chemical precipi-
tation and sedimentation) plus multimedia filtration technology
added at the end of the Option A treatment scheme.
37
-------
COST METHODOLOGY
A detailed discussion of the methpdology used to develop the com-
pliance costs is presented in Section VIII of the General Devel-
opment Document. Projected compliance costs for new source model
plants in the secondary mercury subcategory have been determined
and are presented in the administrative record supporting this
regulation. The costs developed for the proposed regulation are
presented in Table VII'I-1 for model new sources in the secondary
mercury subcategory.
Each of the general assumptions used to develop compliance costs
is presented in Section VIII of the General Development Document.
Each subcategory contains a unique set of waste streams requiring
certain subcategory-specific assumptions to develop compliance
costs. Three major assumptions relevant to the cost estimation
of new source model plants in the secondary mercury subcategory
are discussed briefly below.
(1) Operating hours are assumed to be 2,000 hours per year
(8 hrs/day, 250 days/yr).
(2) Treatment of the furnace wet air pollution control
wastewater stream is not included in the cost estimate
because it is considered a process step in the recovery
of mercury from furnace scrubber liquor.
(3) Pollutant concentration data for the two wastewater
streams included in the treatment scheme were trans-
ferred from the calciner venturi scrubber in the
primary mercury subcategory.
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 specific to the secondary
mercury subcategory, including energy requirements, solid waste,
and air pollution are discussed below.
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 new source model
plants are estimated at 2,300 kWh/yr for Option A and 3,500
kWh/yr for Option C. Option C energy requirements increase over
those for Option A because filtration is being added as an end-
of-pipe treatment technology. Both options represent less than
38
-------
one percent of a typical existing plant's energy usage. It is
therefore expected that the energy requirements of the treatment
options considered will have no significant impact on total plant
energy consumption for new sources.
SOLID WASTE
Sludge generated in the secondary mercury subcategory is due to
the precipitation of metal hydroxides and carbonates using lime.
Sludges associated with the secondary mercury subcategory will
necessarily contain quantities of toxic metal pollutants. Wastes
generated by secondary metal industries can be regulated as
hazardous. However, the Agency examined the solid wastes that
would be generated at secondary nonferrous metals manufacturing
plants by the suggested treatment technologies and believes they
are not hazardous wastes under the Agency's regulations imple-
menting Section 3001 of the Resource Conservation and Recovery
Act. None of the secondary mercury wastes are listed specifi-
cally as hazardous, nor are they likely to exhibit a characteris-
tic of hazardous waste. This judgment is made based on the
recommended technology of lime precipitation and filtration. By
the addition of a small excess of lime during treatment, similar
sludges, specifically toxic metal-bearing sludges, generated by
other industries such as the iron and steel industry passed the
Extraction Procedure (EP) toxicity test. See 40 CFR §261.24.
Thus, the Agency believes that the wastewater sludges will
similarly not be EP toxic if the recommended technology is
applied.
Although it is the Agency's view that solid wastes generated as a
result of these guidelines are not expected to be hazardous,
generators of these wastes must test the waste to determine if
the wastes meet any of the characteristics of hazardous waste
(see 40 CFR 262.11).
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
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
39
-------
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), 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 4004 of RCRA. See 44 FR 53438
(September 13, 1979). It is estimated that a new source model
plant in the secondary mercury subcategory would generate an
estimated 12 kg/yr of sludge when implementing the proposed NSPS
treatment technology, based on a production level of 50 metric
tons of mercury per year. The Agency has calculated as part of
the costs for wastewater treatment the cost of hauling and
disposing of solid wastes. For more details, see Section VIII of
the General Development Document.
AIR POLLUTION
There is no reason to believe that any substantial air pollution
problems will result from implementation of chemical precipita-
tion, sedimentation, and multimedia filtration. These technolo-
gies transfer pollutants to solid waste and are not likely to
transfer pollutants to air.
40
-------
Table VIII-1
COST OF COMPLIANCE FOR NEW SOURCE MODEL
PLANTS IN THE SECONDARY MERCURY SUBCATEGORY*
(March, 1982 Dollars)
Total Required Total
Option Capital Cost Annual Cost
A 1,237 3,070
C . 3,162 4,530
*Based 'on production of 50 metric tons of mercury per year,
41
-------
SECONDARY MERCURY SUBCATEGORY
SECTION IX
BEST PRACTICABLE CONTROL TECHNOLOGY CURRENTLY AVAILABLE
The plants within the secondary mercury subcategory were studied
as to their wastewater handling practices and it was determined
that on the basis of the plants in the data base, BPT was found
to be not applicable to this industrial subcategory. Existing
performance of plants in the secondary mercury subcategory is
such that no discharge of process wastewater is presently prac-
ticed. This is achieved by 100 percent recycle on-site or by
contractor disposal of process wastewater, or is a result of a
production process that generates no process wastewater. The
inappropriateness of effluent limitations, then, leads to the
conclusion that BPT and BAT mass limitations, with their
corresponding treatment technologies, need not be prepared for
this subcategory. Rather, the secondary mercury subcategory will
be regulated under New Source Performance Standards in Section
XI, and Pretreatment Standards for New Sources in Section XII.
43
-------
SECONDARY MERCURY SUBCATEGORY
SECTION X
BEST AVAILABLE TECHNOLOGY ECONOMICALLY ACHIEVABLE
As described in Section IX, BAT is not applicable to the second-
ary mercury subcategory because no plants in the data base
discharge process wastewater. Regulation of the secondary
mercury subcategory is covered in Section XI under New Source
Performance Standards, and Section XII under Pretreatment
Standards for New Sources.
45
-------
SECONDARY MERCURY 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 techno-
logies 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
regulated pollutants for NSPS in the secondary mercury subcate-
gory, based on the selected treatment technology.
TECHNICAL APPROACH TO NSPS
New source performance standards are based on the most effective
and beneficial technologies currently available. The Agency
reviewed and evaluated a wide range of technology options, and
elected to examine two technology options, applied to combined
wastewater streams, which could be applied to the secondary
mercury subcategory as alternatives for the basis of NSPS.
Treatment technologies considered for the NSPS options are
summarized below:
OPTION A (Figure XI-1) is based on:
• Chemical precipitation and sedimentation
OPTION C (Figure XI-2) is based on:
• Chemical precipitation and sedimentation
• Multimedia filtration
As explained in Section IV, the secondary mercury subcategory has
been subdivided into three potential wastewater sources. Since
the water use, discharge ^ates, and pollutant characteristics of
each of these wastewaters is potentially unique, effluent limita-
tions will be developed for each of the three subdivisions.
47
-------
For each of the subdivisions, a specific approach was followed
for the development of NSPS. The first requirement to calculate
these limitations is to account for production and flow varia-
bility from plant to plant. Therefore, a unit of production or
production normalizing parameter (PNP) was determined 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 process within the subcategory was then analyzed to deter-
mine (1) which subdivisions were present, (2) the specific flow
rates generated for each subdivision, and (3) the specific pro-
duction normalized flows for each subdivision. This analysis 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 analyzed to
determine which flow was to be used as part of the basis for
NSPS. The selected flow (sometimes referred to as a NSPS regula-
tory flow or NSPS discharge flow) reflects the water use controls
which are common practices within the industry. The NSPS normal-
ized flow is based on the average of all applicable data.
Nothing was 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 the development of effluent limitations, mass loadings were
calculated for each wastewater source or subdivision. This cal-
culation was made on a stream-by-stream basis, primarily because
plants in this category may perform one or more of the operations
in various combinations. The mass loadings (milligrams of pollu-
tant per metric ton of production unit - mg/kkg) were calculated
by multiplying the NSPS normalized flow (1/kkg) by the treatabil-
ity concentration using the NSPS treatment system (mg/1) for each
pollutant parameter to be limited under NSPS. These mass load-
ings are published in the Federal Register and in CFR Part 400 as
the effluent limitations guidelines.
The mass loadings which are allowed under NSPS for each plant
will be the sum of the individual mass loadings for the various
wastewater sources which are found at particular plants. Accord-
ingly, all the wastewater generated within a plant may be com-
bined for treatment in a single or common treatment system, but
the effluent limitations for these combined wastewaters are based
on the various wastewater sources which actually contribute to
the combined flow. This method accounts for i-Ue variety of com-
binations of wastewater sources and production processes which
may be found at secondary mercury plants.
48
-------
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
As one means of evaluating each technology option, EPA developed
estimates of the pollutant removals and the compliance costs
associated with each option. The methodologies are described
below.
POLLUTANT REMOVAL ESTIMATES
Since there are no existing discharging plants in the secondary
mercury subcategory, the pollutant removal analysis was carried
out for new source model plants.
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 used to
characterize the major waste streams considered for regulation
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 secondary mercury
subcategory. The pollutant removal estimates were calculated for
each plant by first estimating the total mass of each pollutant
in the untreated wastewater. This was calculated by multiplying
the raw waste values by the corresponding new source model plant
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 comparing the actual discharge to the regulatory flow.
The smaller of the two values was selected and summed with 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. The mass of
pollutant removed is the difference between the estimated mass of
pollutant generated within the subcategory and the mass of
pollutant discharged after application of the treatment option.
49
-------
The pollutant removal estimates for the new source model plant in
the secondary mercury subcategory are presented in Table XI-1.
COMPLIANCE COSTS
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 BET 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. The compliance costs
associated with each option are presented in Table XI-2 for new
source model plants in the secondary mercury subcategory. These
costs were used in assessing economic achievability.
NSPS OPTION SELECTION
EPA is proposing that the best available demonstrated technology
for the secondary mercury subcategory be equivalent to Option C
(chemical precipitation, sedimentation, and multimedia filtra-
tion) . This selection is based on an economic analysis of the
two NSPS options and their impact on the cost of building new
production plants within the scope of this subcategory. We
believe the proposed NSPS are economically achievable, and that
they are not a barrier to entry of new plants into this subcate-
gory. The estimated capital cost of proposed NSPS for new source
model plants is $3,162, and the estimated annual cost is $4,530
(1982 dollars), based on production of 50 metric tons of mercury
per year. The end-of-pipe treatment configuration for Option C
is presented in Figure XI-2.
WASTEWATER DISCHARGE RATES
A NSPS 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 concentrations to determine NSPS. Since the
discharge rate may be different for each wastewater source,
separate production normalized discharge rates for each of the
three wastewater sources are discussed below and summarized in
Table XI-3. 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
parameters, or PNP's, are also listed in Table XI-3.
50
-------
Section V of this document further describes the discharge flow
rates and presents production normalized water use and discharge
rates for each plant by subdivision in Tables V-1 through V-3.
SPENT BATTERY ELECTROLYTE
The NSPS wastewater discharge rate for spent battery electrolyte
is 106 liters per kkg of mercury produced from batteries. This
rate is allocated only for those plants which drain electrolyte
from mercuric oxide batteries prior to recovering mercury. Water
use and wastewater discharge rates are presented in Table V-1.
One plant drains spent battery electrolyte, and generates 106
1/kkg.
ACID WASH AND RINSE WATER
The NSPS wastewater discharge rate for acid wash and rinse water
is 2.0 liters per kkg of mercury washed and rinsed. This rate is
allocated only for those plants which further purify their mer-
cury product by washing with acid and then rinsing with water.
Water use and wastewater discharge rates are presented in Table
V-2. One plant further purifies their mercury product in this
manner, and generates 2.0 1/kkg.
FURNACE WET AIR POLLUTION CONTROL
No NSPS wastewater discharge rate for furnace wet air pollution
control is provided based on 100 percent recycle of furnace
scrubber water, as demonstrated at the one plant operating this
process. This is shown in Table V-3.
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 four pollutants or pol-
lutant parameters are selected for limitation under NSPS and are
listed below:
122. lead
123. mercury
TSS
PH
The Agency has chosen not to regulate all four toxic pollutants
selected in Section VI for further consideration.
51
-------
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 analysis.
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
multiple 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. The
mass limits established for lead and mercury will ensure that
thallium and zinc, the other two toxic metals selected for
further consideration, will be adequately removed by a lime and
settle unit.
NEW SOURCE PERFORMANCE STANDARDS
The treatable concentrations achievable by application of the
proposed NSPS are discussed in Section VII of the General
Development Document and summarized there in Table VII-19. These
treatable concentrations (both one day maximum and monthly aver-
age values) are multiplied by the NSPS normalized discharge flows
summarized in Table XI-3 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 NSPS effluent standards and are presented
in Table XI-4 for each individual waste stream.
52
-------
CJ
-O
c oj
o >
•^ o-
4-1 B
-i :
C cd
ox:-
•H U Otj
4-1 CO ,
ev-^
O Q
'O
c
•^ o
4J S
r- CM
i- o
00
o o
>* CM
O O
o o
o o
00 CM
00
00
vO
m
o
o
vO
CT*
• • • • • •
oooooooooooo
CM
CO
a
H
H
co
• on
v£> CM
O CM
o o
o o
r«-
m
o o\
• • • • •
OOOOoOr-OOOOO T—
on
on
o
m
CM
on
•
CM
<
G
O
•r4
4-3
CL
O
£
cd
C4
(1)
00 /-x
M ^
cd >
JS^
o c»c
co ^!
•pH v-/
o
s-\
0) V-i
4J >-
CO -^
cd ex
^^
r*»
o
0
•
0 0
r~-
r-.
0
o
•
0 0
CM
o
o
0
•
0
CM
O
O
O
•
o
vO
o
o
o
•
o o o
CT>
^_
r"
O
•
000
on
o
0
o
•
o o o
o
>d-
-tf
•
r-OO
r-»
CM
o
o
•
0 0
on
on
o
o
•
00
00
o
o
•
o
CT>
en
o
o
•
o
>*
r-
o
o
•
0
in
^o
cr>
•
r—
vO
O
•
O
o
CM
on
-3-
•
o
vO
l-l
I—I
o
CM
efl
4-1
o
H
>. e g
c o g 3 >^ s
O "H 3 -^ ^ H ^-1 -H
gC-^S
Z
o
u
^
H
O
H
CO
H
<3
H
O
n4
J
O
CM
^
EH
O
H
C
o
•H
4J
O
O
lJ
a
c
o
OJ
CO
53
-------
Table XI-2
COST OF COMPLIANCE FOR NEW SOURCE MODEL
PLANTS IN THE SECONDARY MERCURY SUBCATEGORY*
(March, 1982 Dollars)
Total Required Total
Option Capital Cost Annual Cost
A 1,237 3,070
C 3,162 4,530
*Based on production of 50 metric tons of mercury per year,
54
-------
Table XI-3
NSPS WASTEWATER DISCHARGE RATES FOR THE
SECONDARY MERCURY SUBCATEGORY
Wastewater Stream
NSPS Normalized
Discharge Rate
1/kkggal/ton
Spent battery electrolyte 106
Acid wash and rinse water
Furnace wet air pollution
control
2.0,
0
25.5
0.5
0
Production
Normalized
Parameter
mercury produced
from batteries
mercury washed
and rinsed
•
mercury control
processed through
furnace
55
-------
TABLE XI-4
NSPS FOR THE SECONDARY MERCURY SUBCATEGORY
(a) Spent Battery Electrolyte
Pollutant or Maximum for Maximum for
Pollutant Property Any One Day Monthly Average
mg/kg (Ib/million Ibs) of mercury produced from
batteries
Lead 0.030 0.014
Mercury 0.016 0.006
Total suspended 1.590 1.272
solids
pH Within the range of 7.5 to 10.0
at all times
(b) Acid Wash and Rinse Water
Pollutant or Maximum for Maximum for
Pollutant Property Any One Day Monthly Average
mg/kg (Ib/million Ibs) of mercury washed and rinsed
Lead 0.00056 0.00026
Mercury 0.00030 0.00012
Total suspended 0.030 0.024
solids
pH Within the range of 7.5 to 10.0
at all times
(c) Furnace Wet Air Pollution Control
Pollutant or Maximum for Maximum for
Pollutant Property Any One Day Monthly Average
mg/kg (Ib/million Ibs) of mercury processed through
furnace
Lead 0.000 0.000
Mercury 0.000 0.000
Total suspended 0.000 0.000
solids
pH Within the range of 7.5 to 10.0
at all times
56
-------
•o
3.
§
5
I
h-l
X
fa
2
o
g
W
CO
05
H
CO
CO
57
-------
CM
I
I— I
X
0)
60
•H
fa
g
w
w
C/3
V
4J
3
01
58
-------
SECONDARY MERCURY 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 promulgated 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.
PSES will not be proposed for the secondary mercury subcategory
because there are no existing indirect dischargers in this sub-
category. However, PSNS for this subcategory will be proposed.
This section describes the control and treatment technologies for
pretreatment of process wastewaters from new sources in the
secondary mercury subcategory. Pretreatment standards for regu-
lated 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 treat-
ment requirements is less than the percentage removed by direct
59
-------
dischargers complying with BAT effluent limitations guidelines
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 discharg-
ers be equivalent to standards for direct dischargers while at
the same time, (2) that the treatment capability and performance
of the POTW be recognized and taken into account in regulating
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 Section XI.
The options for PSNS, therefore, are the same as the NSPS options
discussed in Section XI.
A description of each option is presented in Section XI, 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
• Chemical precipitation and sedimentation
OPTION C
• Chemical precipitation and sedimentation
• Multimedia filtration
PSNS OPTION SELECTION
Option C (chemical precipitation, sedimentation, and multimedia
filtration) has been selected as the treatment technology for
pretreatment standards for new sources (PSNS) on the basis that
it achieves effective removal of toxic pollutants at a reasonable
60
-------
cost. In addition, filtration is demonstrated in the nonferrous
metals manufacturing category at 25 plants, and will not result
in adverse economic impacts.
The wastewater discharge rates for PSNS are identical to the NSPS
discharge rates for each waste stream. The PSNS discharge rates
are shown in Table XII-1. No additional flow reduction measures
for PSNS are feasible beyond the flow allowances given for NSPS.
REGULATED POLLUTANT PARAMETERS
The toxic pollutants selected for limitation, in accordance with
the rationale of Sections VI and XI, are identical to those
selected for limitation for NSPS. It is necessary to propose
PSNS to prevent the pass-through of lead and mercury, which are
the limited pollutants. The toxic pollutants are removed by a
well operated POTW achieving secondary treatment at an average of
59 percent, while PSNS level technology removes approximately 99
percent.
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 XI for NSPS. 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 con-
centrations for NSPS are identical to those for PSNS. These con-
centrations are listed in Table VII-19 of the General Development
Document. PSNS are presented in Table XII-2.
61
-------
Table XII-1
PSNS WASTEWATER DISCHARGE RATES FOR THE
SECONDARY MERCURY SUBCATEGORY
Wastewater Stream
Acid wash and rinse water
Furnace wet air pollution
control
PSNS Normalized
Discharge Rate
1/kkggal/ton
Spent battery electrolyte 106
2.0
0
25.5
0.5
0
Production
Normalized
Parameter
mercury produced
from batteries
mercury washed
and rinsed
mercury control
processed through
furnace
62
-------
TABLE XI1-2
PSNS FOR THE SECONDARY MERCURY SUBCATEGORY
(a) Spent Battery Electrolyte
Pollutant or Maximum for Maximum for
Pollutant Property Any One Day Monthly Average
mg/kg (lb/million Ibs) of mercury produced from
batteries
Lead 0.030 0.014
Mercury 0.016 0.006
(b) Acid Wash and Rinse Water
Pollutant or Maximum for Maximum for
Pollutant Property Any One Day Monthly Average
mg/kg (lb/million Ibs) of mercury washed and rinsed
Lead 0.00056 0.00026
Mercury 0.00030 0.00012
(c) Furnace Wet Air Pollution Control
Pollutant or Maximum for Maximum for
Pollutant Property Any One Day Monthly Average
mg/kg (lb/million Ibs) of mercury processed through
furnace
Lead 0.000 0.000
Mercury 0.000 0.000
63
-------
64
-------
SECONDARY MERCURY SUBCATEGORY
SECTION XIII
BEST CONVENTIONAL POLLUTANT CONTROL TECHNOLOGY
EPA is not proposing best conventional pollutant control technol'
ogy .(BCT) for the secondary mercury subcategory at this time.
65
------- |