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SECTION III
INTRODUCTION
PURPOSE AND AUTHORITY
The Federal Water Pollution Control Act Amendments of 1972
established a comprehensive program to "restore and maintain the
chemical, physical, and biological integrity of the Nation's
waters," Section 101(a). By July 1, 1977, existing industrial
dischargers were required to achieve "effluent limitations
requiring the application of the best practicable control tech-
nology currently available" (BPT), Section 301 (b)(1)(A). By July
1, 1983, these dischargers were required to achieve "effluent
limitations requiring the application of the best available tech-
nology economically achievable—which will result in reasonable
further progress toward the national goal of eliminating the
discharge of all pollutants" (BAT), Section 301(b)(2)(A}. New
industrial direct dischargers were required to comply with Sec-
tion 306 new source performance standards (NSPS), based on best
available demonstrated technology; and new and existing discharg-
ers to publicly owned treatment works (POTW) were subject to
pretreatment standards under Sections 307(b) and (c) of the Act.
The requirements for direct dischargers were to be incorporated
into National Pollutant Discharge Elimination System (NDPES)
permits issued under Section 402 of the Act. Pretreatment
standards were made enforceable directly against dischargers to
POTW (indirect dischargers).
Although Section 402(a)(1) of the 1972 Act authorized the setting
of requirements for direct dischargers on a case-by-case basis,
Congress intended that, for the most part, control requirements
would be based on regulations promulgated by the Administrator of
EPA. Section 304(b) of the Act required the Administrator to
promulgate regulations providing guidelines for effluent limita-
tions setting forth the degree of effluent reduction attainable
through the application of BPT and BAT. Moreover, Sections
304(c) and 306 of the Act required promulgation of regulations
for NSPS, and Sections 304(f), 307(b), and 307(c) required prom-
ulgation of regulations for pretreatment standards. In addition
to these regulations for designated industry categories, Section
307(a) of the Act required the Administrator to promulgate efflu-
ent standards applicable to all dischargers of toxic pollutants.
Finally, Section 501(a) of the Act authorized the Administrator
to prescribe any additional regulations "necessary to carry out
his functions" under the Act.
EPA was unable to promulgate many of these regulations by the
dates contained in the Act. In 1976, EPA was sued by several
environmental groups, and in settlement of this lawsuit, EPA and
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the plaintiffs executed a "Settlement Agreement" which was
approved by the District Court. This Agreement required EPA to
develop a program and adhere to a schedule for promulgating for
21 major industries BAT effluent limitations guidelines, pre-
treatment standards, and new source performance standards for 65
"priority" pollutants and classes of pollutants. See Natural
Resources Defense Council, Inc. v. Train, 8 ERG 2120 (D.D.C.
1976), modified, 12 ERG 1833 (D.D.C. 1979). modified by addi-
tional orders of August 25, 1982 and October 26, 1982.
On December 27, 1977, the President signed into law the Clean
Water Act of 1977. Although this law makes several important
changes in the Federal water pollution control program, its most
significant feature is its incorporation into the Act of several
of the basic elements of the Settlement Agreement program for
toxic pollution control. Sections 301(b)(2)(A) and 301(b)(2)(C)
of the Act now require the achievement by July 1, 1984 of efflu-
ent limitations requiring application of BAT for "toxic" pollu-
tants, including, the 65 priority" pollutants and classes of
pollutants which Congress declared "toxic" under Section 307(a)
of the Act. Likewise, EPA's programs for new source performance
standards and pretreatment standards are now aimed principally at
toxic pollutant controls. Moreover, to strengthen the toxics
control program, Section 304(e) of the Act authorizes the Admin-
istrator to prescribe "best management practices" (BMP) to
prevent the release of toxic and hazardous pollutants from plant
site runoff, spillage or leaks, sludge or waste disposal, and
drainage from raw material storage associated with, or ancillary
to, the manufacturing.or treatment process.
The 1977 Amendments added Section 301(b)(2)(E) to the Act estab-
lishing "best conventional pollutant control technology" (BCT)
for discharges of conventional pollutants from existing indus-
trial point sources. Conventional pollutants are those mentioned
specifically in Section 304(a)(4) (biochemical oxygen demanding
pollutants (BODO, total suspended solids (TSS), fecal
coliform, and pH), and any additional pollutants defined by the
Administrator as "conventional." (To date, the Agency has added
one such pollutant, oil and grease, 44 FR 44501, July 30, 1979.)
BCT is not an additional limitation but replaces BAT for the con-
trol of conventional pollutants. In addition to other factors
specified in Section 304(b)(4)(B), the Act requires that BCT lim-
itations be assessed in light of a two part "cost-reasonableness"
test, American Paper Institute v. EPA, 660 F.2d 954 (4th Cir.
1981).The first test compares the cost for private industry to
reduce its conventional pollutants with the costs to publicly
owned treatment works for similar levels of reduction in their
discharge of these pollutants. The second test examines the
cost-effectiveness of additional industrial treatment beyond BPT.
EPA must find that limitations are "reasonable" under both tests
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before establishing them as BCT. In no case may BCT be less
stringent than BPT.
EPA published its methodology for carrying out the BCT analysis
on August 29, 1979 (44 FR 50372). In the case mentioned above,
the Court of Appeals ordered EPA to correct data errors underly-
ing EPA's calculation of the first test, and to apply the second
cost test. (EPA had argued that a second cost test was not
required.)
A revised methodology for the general development of BCT limita-
tions was proposed on October 29, 1982 (47 FR 49176), but has not
been promulgated as a final rule. We accordingly have not pro-
posed BCT limits for plants in the nonferrous metals manufactur-
ing phase II category. We will await establishing nationally
applicable BCT limits for this industry until promulgation of the
final methodology for BCT.
For non-toxic, nonconventional pollutants, Sections 301 (b)(2)(A)
and (b)(2)(F) require achievement of BAT effluent limitations
within three years after their establishment or July 1, 1984,
whichever is later, but not later than July 1, 1987.
The purpose of these proposed regulations is to provide effluent
limitations guidelines for BPT and BAT, and to establish NSPS,
pretreatment standards for existing sources (PSES), and pretreat-
ment standards for new sources (PSNS), under Sections 301, 304,
306, 307, and 501 of the Clean Water Act.
PRIOR EPA REGULATIONS
EPA already has promulgated effluent limitations and pretreatment
standards for certain nonferrous metals manufacturing subcate-
gories. These regulations, and the technological basis are
summarized below.
Nonferrous Phase I. On March 8, 1984, EPA promulgated rules for
nonferrous metals manufacturing phase I (49 FR 8742), which
established BPT, BAT, NSPS, PSES, and PSNS for 12 subcategories.
They are: primary aluminum, copper smelting, copper electrolytic
refining, lead, zinc, columbium-tantalum, and tungsten; secondary
aluminum, silver, copper, lead, and metallurgical acid plants.
Bauxite Refining Subcategory. EPA has promulgated BPT, BAT,
NSPS, and PSNS in this subcategory (39 FR 12822, March 26, 1974).
BPT, BAT, NSPS and PSNS are based on zero discharge of process
wastewater, but do allow for a monthly net precipitation dis-
charge from the red mud impoundment. The Agency is presently
proposing only technical amendments to these existing regula-
tions ; however, EPA is also providing notice that it is con-
sidering toxic limitations on the net precipitation discharges
from bauxite red mud impoundments.
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Metallurgical Acid Plants. This subcategory was established in
1980, and at that time included only acid plants (i.e., plants
recovering by-product sulfuric acid from sulfur dioxide smelter
air emissions) associated with primary copper smelting opera-
tions. See 45 FR 44926. Primary lead and zinc plants also have
associated acid plants ; the applicability of the metallurgical
acid plants subcategory was expanded to include these sources in
the phase I regulation (see below) finalized on March 8, 1984 (49
FR 8742). EPA has proposed to expand the existing regulation for
metallurgical acid plants by modifying the applicability of the
metallurgical acid plants subcategory to include molybdenum acid
plants (see Sections IX, X, XI, and XII of this document and the
primary molybdenum and rhenium supplement).
METHODOLOGY
Approach of Study
The nonferrous metals manufacturing category comprises plants
that process ore concentrates and scrap metals to recover and
increase the metal purity contained in these materials. In
keeping with Agency priorities to regulate first those plants
which generate the largest quantities of toxic pollutants, EPA
has divided the nonferrous metals category into separate segments
(nonferrous metals manufacturing phase I and nonferrous metals
manufacturing phase II).
EPA promulgated regulations for nonferrous metals manufacturing
phase I (49 FR 8742)"on March 8, 1984. Twelve subcategories were
addressed at that time. The proposed regulatory strategy for
nonferrous metals phase II addresses an additional 21
subcategories:
Bauxite Refining
Primary Antimony
Primary Beryllium
Primary Boron
Primary Cesium and Rubidium
Primary and Secondary Germanium and Gallium
Secondary Indium
Secondary Mercury
Primary Molybdenum and Rhenium
Secondary Molybdenum and Vanadium
Primary Nickel and Cobalt
Secondary Nickel
Primary Precious Metals and Mercury
Secondary Precious Metals
Primary Rare Earth Metals
Secondary Tantalum
Primary and Secondary Tin
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Primary and Secondary Titanium
Secondary Tungsten and Cobalt
Secondary Uranium
Primary Zirconium and Hafnium
The 21 subcategories in nonferrous metals manufacturing phase II
contain 34 primary metals and metal groups, 20 secondary metals
and metal groups, and bauxite refining. A group of metals--
including, six primary metals and five secondary metals--were
excluded from regulation in a Paragraph 8 affidavit executed pur-
suant to the Settlement Agreement on May 10, 1979. These metals
were excluded from regulation either because the manufacturing
processes do not use water or because they are regulated by
toxics limitations and standards in other categories (e.g.,
ferroalloys and inorganic chemicals). Four of these metals which
were excluded from regulation on May 10, 1979--primary antimony,
primary tin, secondary molybdenum, and secondary tantalum—have
since been reconsidered based on information received during the
data collection portion of nonferrous phase II. EPA also has
studied the segments of the nonferrous metals industry associated
with forming or casting nonferrous metals. EPA promulgated regu-
lations for aluminum forming (48 FR 49126) in October, 1983, and
for copper forming (48 FR 36942) in August, 1983. Proposed regu-
lations for metal molding and casting (47 FR 51512) were issued
in November, 1982. Proposed regulations for forming of nonfer-
rous metals other than aluminum and copper (49 FR 8112) were
issued on March 5, 1984.
EPA gathered and evaluated technical data in the course of devel-
oping these guidelines in order to perform the following tasks:
1. To. profile the category with regard to the production,
manufacturing.processes, geographical distribution,
potential wastewater streams, and discharge mode of
nonferrous metals manufacturing plants.
2. To subcategorize, if necessary, in order to permit
regulation of the nonferrous metals manufacturing
category in an equitable and manageable way.
3. To characterize wastewater, detailing.water use, waste-
water discharge, and the occurrence of toxic, conven-
tional, and nonconventional pollutants, in waste streams
from nonferrous metals manufacturing processes.
4. To select pollutant parameters--those toxic, nonconven-
tional, or conventional pollutants present at signifi-
cant concentrations in wastewater streams--that should
be considered for regulation.
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5. To consider control and treatment technologies and
select alternative methods for reducing pollutant dis-
charge in this category.
6. To evaluate the costs of implementing the alternative
control and treatment technologies.
7. To present regulatory alternatives.
Data Collection and Methods of Evaluation
Data on the nonferrous metals manufacturing category were gath-
ered from previous EPA studies, literature studies, inquiries to
federal and state environmental agencies, trade association con-
tacts and the manufacturers themselves. Meetings were also held
with industry representatives and the EPA. All known companies
within the nonferrous metals manufacturing category were sent
data collection portfolios to solicit specific information con-
cerning each facility. Finally, a sampling program was carried
out at 29 plants. Wastewater samples were collected in two
phases. In the first phase, 20 plants were sampled in an attempt
to characterize all the significant waste streams and production
processes in these industries. In the second phase, we sampled
eight plants in an attempt to fill any data gaps in the data
base, and to confirm data acquired during the first phase of
sampling. An additional facility was sampled by EPA Regional
personnel. Samples were generally analyzed for 124 of the 126
toxic pollutants and other pollutants deemed appropriate.
Because no analytical standard was available for TCDD, samples
were never analyzed for this pollutant, although there is no
reason that it would be present in nonferrous metals manufactur-
ing wastewater. Asbestos was not analyzed for in any of the sam-
ples because there was no reason to believe it would be present
in wastewater resulting from the manufacture of nonferrous
metals. There were no samples collected at primary antimony,
primary boron, secondary mercury, secondary molybdenum and
vanadium, and secondary uranium plants. In general, at least one
plant in every major subcategory was sampled during the data
collection effort, with some subcategories sampled at more than
one plant, when the production processes were different.
Specific details of the sampling program and information from the
above data sources are presented in Section V. Details on selec-
tion of plants for sampling, and analytical results, are con-
tained in Section V of each of the subcategory supplements.
Literature Review. EPA reviewed and evaluated existing litera-
ture for background information to clarify and define various
aspects of the nonferrous metals manufacturing category and to
determine general characteristics and trends in production pro-
cesses and wastewater treatment technology. Review of current
96
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literature continued throughout the development of these limita-
tions and standards. Information gathered in this review was
used, along with information from other sources as discussed
below, in the following specific areas:
Introduction (Section III of each of the subcategory
supplements) - Description of production processes and
the associated lubricants and wastewater streams.
Subcategorization (Section IV of each of the subcategory
supplements) - Identification of differences in manufac-
turing process technology and their potential effect on
associated wastewater streams.
Selection of Pollutant Parameters (Section VI) - Infor-
mation regarding the toxicity and potential sources of
the pollutants identified in wastewater from nonferrous
metals manufacturing processes.
Control and Treatment Technology (Section VII) - Infor-
mation on alternative controls and treatment and
corresponding effects on pollutant removal.
Costs (Section VIII) - Formulation of the methodology
for determining the current capital and annual costs to
apply the selected treatment alternatives.
Existing Data. Previous EPA studies of the following nonferrous
metals manufacturing (phase II) subcategories were reviewed:
Primary Beryllium
Primary and Secondary Germanium
Primary Magnesium
Secondary Zinc
Primary Zirconium and Hafnium
The available information included a summary of the category
describing the production processes, the wastewater characteris-
tics associated with the processes, recommended pollutant param-
eters requiring control; applicable end-of-pipe treatment tech-
nologies for wastewaters; effluent characteristics resulting from
this treatment, and a background bibliography. Also included in
these studies were detailed production and sampling information
for many plants.
The concentration or mass loading of pollutant parameters in
wastewater effluent discharges are monitored and reported as
required by individual state agencies. Where available, these
historical data were obtained from NPDES monitoring reports and
reviewed.
97
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Another useful data source is contact with industry personnel and
trade associations. Contributions from these sources were par-
ticularly useful for clarifying differences in production
processes. Finally, general information was derived from publi-
cations of the U.S. Bureau of Mines, including the Minerals
Yearbook and supplements, and through discussions with commodity
experts at the U.S. Bureau of Mines.
Data Collection Portfolios. EPA conducted a survey of the non-
ferrous metals manufacturing plants to gather information
regarding plant size, age and production, the production proces-
ses used, economic parameters, and the quantity, treatment, and
disposal of wastewater generated at these plants. This informa-
tion was requested in data collection portfolios (dcp) mailed to
all companies known or believed to belong to the phase II nonfer-
rous metals manufacturing category. A listing of the companies
comprising the nonferrous metals industry (as classified by
standard industrial code numbers) was compiled by consulting
trade associations and the U.S. Bureau of Mines.
In all, dcp were sent to 220 firms (276 plants). In many cases,
companies contacted were not actually members of the nonferrous
metals manufacturing category as it is defined by the Agency.
Where firms had nonferrous metals manufacturing operations at
more than one location, a dcp was returned for each plant.
If the dcp was not returned, information on production processes,
sources of wastewater and treatment technology at these plants
was collected by telephone interview. The information so gath-
ered was validated by sending a copy of the information recorded
to the party consulted. The information was assumed to be cor-
rect as recorded if no reply was received in 30 days. In total,
more than 99 percent of the category was contacted either by mail
or by telephone.
A total of 141 dcp applicable to the nonferrous metals manufac-
turing category were returned. A breakdown of these facilities
by type of metal processed is presented in Table III-1 (page 101 ).
The dcp responses were interpreted individually, and the follow-
ing data were documented for future reference and evaluation:
Company name, plant address, and name of the contact
listed in the dcp.
Plant discharge status as direct (to surface water),
indirect (to POTW), or zero discharge.
Production process and waste streams present at the
plant, as well as associated flow rates; production
rates; operating hours; wastewater treatment, reuse,
or disposal methods ; and the quantity and nature of
process chemicals.
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Capital and annual wastewater treatment costs.
Availability of pollutant monitoring data provided by the
plant.
The summary listing of this information provided a consistent,
systematic method of evaluating and summarizing the dcp
responses. In addition, procedures were developed to simplify
subsequent analyses. The procedures developed had the following
capabilities:
Selection and listing of plants containing specific pro-
duction process streams or treatment technologies.
Summation of the number of plants containing specific
process waste streams and treatment combinations.
Calculation of the percent recycle present for specific
waste streams and summation of the number of plants
recycling these waste streams within various percent
recycle ranges.
Calculation of annual production values associated with
each process stream and summation of the number of plants
with these process streams having.production values
within various ranges.
Calculation of wat-er use and discharge from individual
process streams.
The calculated information and summaries were used in developing
these effluent limitations and standards. Summaries were used in
the category profile, evaluation of subcategorization, and analy-
sis of in-place treatment and control technologies. Calculated
information was used in the determination of water use and dis-
charge values for the conversion of pollutant concentrations to
mass loadings.
GENERAL PROFILE OF THE NONFERROUS METALS MANUFACTURING CATEGORY
The nonferrous metals manufacturing point source category encom-
passes the primary smelting and refining of nonferrous metals
(Standard Industrial Classification (SIC) 333) and the secondary
smelting and refining of nonferrous metals (SIC 334). The cate-
gory does not include the mining and concentrating of ores, roll-
ing, drawing, or extruding of metals, or scrap metal collection
and preliminary grading.
Nonferrous metal manufacturers include processors of ore concen-
trates or other virgin materials (primary) and processors of
99
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scrap (secondary). Metals produced as by- or co-products of pri-
. mary metals are themselves considered primary metals. For exam-
ple, rhenium recovered from primary molybdenum roaster flue gases
is considered to be primary rhenium, rather than secondary.
The nonferrous metals manufacturing category is quite complex and
the production process for a specific metal is dictated by the
characteristics of raw materials, the economics of by-product
recovery, and the process chemistry and metallurgy of the metals.
Employment data are given in the dcp responses for 141 plants.
These plants report a total of 13,500 workers involved in nonfer-
rous metals manufacturing phase II plants. Industry production
figures show that bauxite refining dominates the industry in
terms of tonnage. Other subcategories with large production
figures are primary molybdenum and rhenium, primary and secondary
tin, and primary and secondary titanium.
Seventy-one plants (50 percent) indicated that no wastewater from
phase II nonferrous metals manufacturing operation is discharged
to either surface waters or a POTW. Of the remaining 70, 32 (23
percent) discharge an effluent from phase II nonferrous metals
manufacturing directly to surface waters, and 38 (27 percent)
discharge indirectly, sending nonferrous metals manufacturing
effluent through a POTW.
EPA recognizes that plants sometimes combine process and non-
process wastewater prior to treatment and discharge. Pollutant
discharge allowances will be established under this regulation
only for nonferrous metals manufacturing process wastewater, not
the nonprocess wastewaters. The flows and wastewater character-
istics are a function of the plant layout and water handling
practices. As a result, the pollutant discharge effluent limita-
tion for nonprocess wastewater streams will be prepared by the
permitting authority. A discussion of how a permitter would
construct a permit for a facility that combines wastewater is
presented in Section IX.
Section III of each of the subcategory supplements presents a
detailed profile of the plants in each subcategory and describes
the production processes involved. In addition, the following
specific information is presented:
1. Raw materials ,
2. Manufacturing process,
3. Geographic locations of manufacturing plants ,
4. Age of plants by discharge status,
5. Production ranges by discharge status, and
6. Summary of waste streams for each process.
100
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Table III-1
BREAKDOWN. OF DCP RESPONDENTS BY TYPE OF METAL PROCESSED
Subcategory
Bauxite Refining
Primary Antimony
Primary Beryllium
Primary Boron
Primary Cesium and Rubidium
Primary and Secondary Germanium and Gallium
Secondary Indium
Secondary Mercury
Primary Molybdenum and Rhenium
Secondary Molybdenum and Vanadium
Primary Nickel and Cobalt
Secondary Nickel
Primary Precious Metals and Mercury
Secondary Precious Metals
Primary Rare Earth Metals
Secondary Tantalum
Primary and Secondary Tin
Primary and Secondary Titanium
Secondary Tungsten and Cobalt
Secondary Uranium
Primary Zirconium and Hafnium
TOTAL
Number
of Plants
8
7
2
2
1
5
1
4
13
1
1
2
8
48
4
3
12
8
5
3
3
141
101
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SECTION IV
INDUSTRY SUBCATEGORIZATION
Subcategorization should take into account pertinent industry
characteristics, manufacturing process variations, wastewater
characteristics, and other factors. Effluent limitations and
standards establish mass limitations on the discharge of pollu-
tants which are applied, through the permit issuance process, to
specific dischargers. To allow the national standard to be
applied to a wide range of sizes of production units, the mass of
pollutant discharge must be referenced to a unit of production.
This factor is referred to as a production normalizing parameter
and is developed in conjunction with Subcategorization.
Division of the category into subcategories provides a mechanism
for addressing process and product variations which result in
distinct wastewater characteristics. The selection of production
normalizing parameters provides the means for compensating for
differences in production rates among plants with similar prod-
ucts and processes within a uniform set of mass-based effluent
limitations and standards.
This Subcategorization analysis is actually an ongoing process.
The first subcategories (bauxite refining, primary aluminum
smelting, and secondary aluminum smelting) were established in a
1973 Agency rulemaking. Since that time, some subcategories have
been modified. New subcategories have been added in 1975, 1980,
and then again in 1983.
A comprehensive analysis of each factor that might warrant sepa-
rate limitations for different segments of the industry has led
the Agency to propose the following Subcategorization scheme for
proposal of BPT and BAT effluent limitations guidelines and PSNS,
PSES, and NSPS in the nonferrous metals manufacturing category
(phase II) :
1. Bauxite Refining
2. Primary Antimony
3. Primary Beryllium
4. Primary Boron
5. Primary Cesium and Rubidium
6. Primary and Secondary Germanium and Gallium
7. Secondary Indium
8. Secondary Mercury
9. Primary Molybdenum and Rhenium
10. Secondary Molybdenum and Vanadium
11. Primary Nickel and Cobalt
12. Secondary Nickel
13. Primary Precious Metals and Mercury
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14. Secondary Precious Metals
15. Primary Rare Earth Metals
16. Secondary Tantalum
17. Primary and Secondary Tin
18. Primary and Secondary Titanium
19. Secondary Tungsten and Cobalt
20. Secondary Uranium
21. Primary Zirconium and Hafnium
Most of these subcategories are further segmented into subdivi-
sions for the development of effluent limitations; these subdivi-
sions are enumerated and discussed in the subcategory supplements
to this document.
SUBCATEGORIZATION BASIS
Technology-based effluent limitations are based primarily upon
the treatability of pollutants in wastewaters generated by the
category under review. The treatability of these pollutants is,
of course, directly related to the flow and characteristics of
the untreated wastewater, which in turn can be affected by fac-
tors inherent to a processing plant in the category. Therefore,
these factors and the degree to which each influences wastewater
flow and characteristics form the basis for subcategorization of
the category, i.e., those factors which have a strong influence
on untreated wastewater flow and characteristics are applied to
the category to subcategorize it in an appropriate manner.
The list of potential subcategorization factors considered for
the nonferrous metals manufacturing category include:
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. Solid waste generation and disposal;
12. Number of employees;
13. Total energy requirements (manufacturing process and
waste treatment and control); and
14. Unique plant characteristics.
For the reasons discussed below, the metal or other products, the
raw materials, and the manufacturing process were discovered to
have the greatest influence on wastewater flow charateristics and
treatability, and thus ultimately on the appropriateness of
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effluent limitations. These three factors were used to subcate-
gorize the category. As mentioned previously, further division
of some subcategories is warranted based on the sources of waste-
waters (manufacturing processes) within the plant. Each manufac-
turing, process generates differing amounts of wastewater and in
some instances specific waste streams contain pollutants requir-
ing preliminary treatment to reduce concentrations of oil and
grease, ammonia, cyanide, and toxic organics prior to combined
treatment. Thus, each subcategory is further subdivided based on
the manufacturing processes used. These subdivisions are dis-
cussed in the appropriate supplement.
Metal Products, Co-Products, and By-Products
The metal products, co-products, and by-products is the most
important factor in identifying subcategories for this category.
Subcategorizing on this basis is consistent with the existing
division of plants, i.e., plants are identified as (and identify
themselves as) nickel plants, tin plants, titanium plants, etc.
The production of each metal is based on its own raw materials
and production processes, which directly affect wastewater volume
and charateristics.
In nonferrous metals phase II, production and refining of metal
by-products and co-products generally will be covered by means of
subcategorization with the major metal product. There are
several examples of this. EPA found that production of the
co-product metals primary zirconium and hafnium are inherently
allied, so both were considered in a single subcategory. The
same is true for primary molybdenum and rhenium, primary nickel
and cobalt, primary precious metals and mercury, and primary rare
earth metals. Secondary cobalt is a by-product of the secondary
tungsten manufacturing process, thus, the two are placed together
in one subcategory.
Raw Materials
The raw materials used (ore concentrates or scrap) in nonferrous
metals manufacturing determine the reagents used, and to a large
extent the wastewater characteristics. Raw materials are signi-
ficant in differentiating between primary and secondary produc-
ers. It is therefore selected as a basis for subcategorization.
In some cases (e.g., primary and secondary titanium), the raw
material differences did not warrant separate subcategorization
due to common processing steps or other factors.
Manufacturing Processes
The production processes for each metal are unique and are
affected by the raw materials used and the type of end product.
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The processes used will, in turn, affect the volume and charac-
teristics of the resulting wastewater.
The processes performed (or the air pollution controls used on
the process emissions) in the production of nonferrous metals
determine the amount and characteristics of wastewater generated
and thus are a logical basis for the establishment of subcate-
gories. In this category, however, similar processes may be
applied to differing raw materials in the production of different
metals yielding different wastewater characteristics. For exam-
ple, molybdenum, precious metals, and tin may all be produced by
roasting. As a result of these considerations, specific process
operation was not generally found to be suitable as a primary
basis for subcategorization. However, process variations which
result in significant differences in wastewater generation are
reflected in the allowances for discrete unit operations within
each subcategory (see the discussion of building blocks in
Section IX).
Product Form
This factor becomes important when the final product from a plant
is actually an intermediate that another plant purchases and pro-
cesses to render the metal in a different form. An example of
this is the production of molybdenum, which some plants produce
by reducing molybdenum trioxide (MoC^), an intermediate that
may have been produced by another plant. This practice, however,
is not found to be common in the category and its effect on
wastewater volume and total subcategory raw waste generation is
not as significant as the factors chosen.
Plant Location
Most plants in the category are located near raw materials
sources, transportation centers, markets, or sources of inexpen-
sive energy. While larger primary precious metals and mercury,
molybdenum and titanium producers are mainly found near Mid-
western and Western ores and are remote from population centers,
proximity to shipping lanes in the lower Mississippi region is
important for bauxite refiners. Secondary producers, on the
other hand, are generally located in or near large metropolitan
areas. Therefore, primary producers often have more land avail-
able for treatment systems than secondary producers. Plant loca-
tion also may be significant because evaporation ponds can be
used only where solar evaporation is feasible and where suffi-
cient land is available. However, location does not signifi-
cantly affect wastewater characteristics or treatability, and
thus different effluent limitations are not warranted based on
this factor.
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Plant Age
•
Plants within a given subcategory may have significantly differ-
ent ages in terms of initial operating year. To remain competi-
tive, however, plants must be constantly modernized.
Plants may be updated by modernizing a particular component, or
by installing new components. For example, an old furnace might
be equipped with oxygen lances to increase the throughput, or
replaced entirely by a new, more efficient furnace. Moderniza-
tion of production processes and air pollution control equipment
produces analogous wastes among all plants producing a given
metal, despite the original plant start-up date. While the rela-
tive age of a plant may be important in considering the economic
impact of a guideline, as a subcategorization factor it does not
account for differences in the raw wastewater characteristics.
For these reasons, plant age is not selected as a basis for
subcategorization.
Plant Size
The size of a plant generally does not affect either the produc-
tion methods or the wastewater characteristics. Generally, more
water is used at larger plants. However, when water use and
discharge are normalized on a production basis, no major differ-
ences based on plant size are found within the same subcategory.
Thus, plant size is not selected as a basis for subcategoriza-
tion.
Air Pollution Control Methods
Many facilities use wet scrubbers to control emissions which
influence wastewater characteristics. In some cases, the type of
air pollution control equipment used provides a basis for regula-
tion, because if wet air pollution control is used, an allowance
may be necessary for that waste stream, while a plant using only
dry systems does not need an allowance for a non-existent waste
stream. Therefore, this factor is often selected as a basis for
subdivision within some subcategories (i.e., developing an allow-
ance for this unit operation as part of the limitation or stan-
dard for the subcategory), but not as a means for subcategorizing
the category.
Meteorological Conditions
Climate and precipitation may affect the feasibility of certain
treatment methods, e.g., solar evaporation through the use of
impoundments is a feasible method of wastewater treatment only in
areas of net evaporation. This factor was not selected for sub-
categorization, however, because the differences in wastewater
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characteristics and treatability are better explained by other
factors such as metal products and manufacturing processes.
Therefore, different effluent limitations based on this factor
are not warranted.
Solid Waste Generation and Disposal
Physical and chemical characteristics of solid waste generated by
the nonferrous metals category are determined by the raw mate-
rial, process, and type of air pollution control in use. There-
fore, this factor does not provide a primary basis for subcatego-
rization.
Number of Employees
The number of employees in a plant does not directly provide a
basis for subcategorization because the number of employees does
not directly affect the production or process water usage rate at
any plant. Because the amount of process wastewater generated is
related to the production rates rather than employee number, the
number of employees does not provide a definitive relationship to
wastewater generation.
Total Energy Requirements
Total energy requirements was not selected as a basis for sub-
categorization primarily because energy requirements are found to
vary widely within this category and are not meaningfully related
to wastewater generation and pollutant discharge. Additionally,
it is often difficult to obtain reliable energy estimates spe-
cifically for production and waste treatment. When available,
estimates are likely to include other energy requirements such as
lighting, air conditioning, and heating or cooling energy.
Unique Plant Characteristics
Unique plant characteristics such as land availability and water
availability do not provide a proper basis for subcategorization
because they do not materially affect the raw wastewater charac-
teristics of the plant. Process water availability may indeed be
a function of the geography of a plant. However, the impact of
limited water supplies is to encourage conservation by recycle
and efficient use of water. As explained in Section VII, this is
consistent with EPA's approach to establishing limitations for
all plants. Therefore, insufficient water availability only
tends to encourage the early installation of practices that EPA
believes are advisable for the entire category in order to reduce
treatment costs and improve pollutant removals.
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Limited land availability for constructing a waste treatment
facility may affect the economic impact of an effluent limita-
tion. The availability of land for treatment, however, is gen-
erally not a major issue in the nonferrous metals manufacturing
category. Most primary plants are located on very large sites
and land availability would not be a factor. While secondary
producers tend to be located in more urban settings, the amount
of land available to them for treatment is sufficient for the
types of treatment and control technologies considered.
PRODUCTION NORMALIZING PARAMETERS
To ensure equitable regulation of the category, effluent guide-
lines limitations and standards of performance are established on
a production-related basis, i.e., a mass of pollutant per unit of
production. In addition, by using these mass-based limitations,
the total mass of pollutants discharged is minimized. The under-
lying premise for mass-based limitations is that pollutant load-
ings and water discharged from each process are correlated to the
amount of material produced on that process. This correlation is
calculated as the mass of pollutant or wastewater discharged per
unit of production. The units of production are known as produc-
tion normalizing parameters (PNPs). The type and value of the
PNPs vary according to the subcategory or subdivision. In one
case it may be the total mass of metal produced from that line
while in others it may be some other characteristic parameter.
Two criteria are used in selecting the appropriate PNP for a
given subcategory or subdivision: (1) maximizing the degree of
correlation between the production of metal reflected by the PNP
and the corresponding discharge of pollutants, and (2) ensuring
that the PNP is easily measured and feasible for use in
establishing regulations.
The production normalizing parameter identified for each subcate-
gory or subdivision, and the rationale used in selection are dis-
cussed in detail in Section IV of the appropriate supplements.
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SECTION V
WATER USE AND WASTEWATER CHARACTERISTICS
This section presents the data collection and data analysis meth-
ods used for characterizing water use and wastewater associated
with the nonferrous metals manufacturing category. Raw waste and
treated effluent sample data, and production normalized water use
and wastewater discharge data are presented for each subcategory
in Section V of each of the subcategory supplements.
DATA SOURCES
Data Collection Portfolios
Information on plant location and size, number of employees, dis-
charge status, production processes and quantities, wastewater
sources and flows, treatment system processes, operations and
costs, economic information, and pollutant characterization data
was solicited in the dcp.
Two of the most important items are the production processes and
quantities and the associated flows. These data were evaluated,
and two flow-to-production ratios were calculated for each stream
in each subcategory. The two ratios, water use and wastewater
discharge flow, are differentiated by the flow value used in cal-
culation. Water use is defined as the volume of water or other
fluid required for a given process per mass of metal product and
is therefore based on the sum of recycle and make-up flows to a
given process. Wastewater flow discharged after preliminary
treatment or recycle (if these are present) is the volume of
wastewater discharged from a given process to further treatment,
disposal, or discharge per mass of metal produced. It is this
value that is used in the calculation of the production normal-
ized flow. The production values used in this calculation corre-
spond to the production normalizing parameter, PNP, assigned to
each stream, as outlined in Section IV of each of the subcategory
supplements. This value is most often the amount of metal pro-
cessed by each operation that generates a wastewater.
The production normalized water use and discharge flows were com-
piled and summarized for each stream. The flows are presented in
Section V of each of the subcategory supplements. Where appro-
priate, an attempt was made to identify factors that could
account for variations in water USQ- The flows for each stream
were evaluated to establish BPT, BAT, NSPS, and pretreatment dis-
charge flows. These are used in calculating the effluent limita-
tions and standards in Sections IX, X, XI, and XII of each of the
subcategory supplements.
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The regulatory production normalized discharge flows were also
used to estimate flows at nonferrous metals manufacturing plants
that supplied EPA with only production data in their dcp. Actual
discharge flows, or estimated flows, when an actual flow was not
reported in the dcp, were then used to determine the cost of
various wastewater treatment options at these facilities.
Sampling and Analysis Program
The sampling and analysis program discussed in this section was
undertaken primarily to implement the requirements of the 1977
amendments to the Act and of the Settlement Agreement, and to
identify pollutants of concern in the nonferrous metals manufac-
turing point source category, with emphasis on toxic pollutants.
EPA and its contractors collected and analyzed samples from 29
phase II nonferrous metals manufacturing facilities.
This section summarizes the purpose of the sampling trips and
identifies the sites sampled and parameters analyzed. It also
presents an overview of sample collection, preservation, and
transportation techniques. Finally, it describes the pollutant
parameters quantified, the methods of analyses and laboratories
used, the detectable concentration of each pollutant, and the
general approach used to ensure the reliability of the analytical
data produced.
Site Selection. Information gathered in the data collection
portfolios was used to select sites for wastewater sampling for
each subcategory. The plants sampled were selected to be
representative of each subcategory. Considerations included how
well each facility represented the subcategory as indicated by
available data, potential problems in meeting technology-based
standards, differences in production processes used, number and
variety of unit operations generating wastewater, and wastewater
treatment in place. Additional details on site selection are
presented in Section V of each of the subcategory supplements.
Field Sampling. After selection of the plants to be sampled,
each plant was contacted by telephone, and a letter of notifica-
tion was sent to each plant as to when a visit would be expected.
These inquiries led to acquisition of facility information neces-
sary for efficient on-site sampling. The information resulted in
selection of the sources of wastewater to be sampled at each
plant. The sample points included, but were not limited to,
untreated and treated discharges, process wastewater, and par-
tially treated wastewater.
During this program, 29 nonferrous metals manufacturing plants
were sampled. The distribution of these plants by subcategory is
presented in Table V-1 (page 119 ).
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Wastewater samples were collected in two stages. In the first
stage, a large number of plants (20) were sampled in an attempt
to characterize all the significant waste streams and production
processes in these industries. In the second stage, we sampled a
smaller number of plants (eight), in an attampt to fill any gaps
in the data base, and to confirm data acquired during the first
phase of sampling. One facility was sampled by EPA Regional
personnel. Samples were generally analyzed for 124 of the 126
toxic pollutants and other pollutants deemed appropriate.
(Because no analytical standard was available for TCDD, samples
were never analyzed for this pollutant, although there is no
reason that it would be present in nonferrous metals manufactur-
ing wastewater.) At least one plant in every major subcategory
was sampled during the data collection effort, with some catego-
ries sampled at more than one plant, when the production proces-
ses were different. For example, both MoS2 roasting and Mo03
reduction plants were sampled in the primary molybdenum and
rhenium subcategory.
To reduce the volume of data handled, avoid unnecessary expense,
and direct the scope of the sampling program, analyses were not
performed for a number of pollutants not expected to be present
in a plant's wastewater. This determination was based on raw
materials and production processes used. Two sources of infor-
mation were used for selecting the analyzed pollutants: the
pollutants that industry believes or knows are present in their
wastewater, and the pollutants the Agency believes could be
present after studying the processes and materials used by the
industry. If industry and the Agency did not believe a pollutant
or class of pollutants could likely be present in the wastewater
after studying the processes and materials used, analyses for
that pollutant were not run. EPA collected this information in
the following manner.
The 126 toxic pollutants were listed in each dcp and each facil-
ity was asked to indicate for each particular pollutant whether
it was known to be present or believed to be present. If the
pollutant had been analyzed for and detected, the facility was to
indicate that it was known to be present. If the pollutant had
not been analyzed, but might be present in the wastewater, the
facility was to indicate that it was believed to be present. The
reported results are tabulated in Section V of each of the sub-
category supplements.
Sample Collection, Preservation, and Transportation. Collection,
preservation, and transportation of samples were accomplished in
accordance with procedures outlined in Appendix III of "Sampling
and Analysis Procedures for Screening of Industrial Effluents for
Priority Pollutants" (published by the Environmental Monitoring
and Support Laboratory, Cincinnati, Ohio, March 1977, revised,
April 1977), "Sampling Screening Procedure for the Measurement of
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Priority Pollutants" (published by the EPA Effluent Guidelines
Division, Washington, D.C., October 1976), and in Handbook for
Sampling.and Sample Preservation of Water and Wastewater (pub-
lished by the Environmental Monitoring and Support Laboratory,
Cincinnati, Ohio, September 1982). The procedures are summarized
in the paragraphs that follow.
Whenever practical, all samples collected at each sampling point
were taken from mid-channel at mid-depth in a turbulent, well-
mixed portion of the waste stream. Periodically, the temperature
and pH of each waste stream sampled were measured on-site.
Before collection of automatic composite samples, new Tygon® tub-
ing was cut to minimum lengths and installed on the inlet and
outlet (suction and discharge) fittings of the automatic sampler.
Two liters (2.1 quarts) of blank water, known to be free of
organic compounds and brought to the sampling site from the
analytical laboratory, were pumped through the sampler and its
attached tubing into a 3.8 liter (1 gallon) glass jug; the water
was then distributed to cover the interior of the jug and sub-
sequently discarded.
A field blank sample was produced by pumping an additional three
liters (0.8 gal) of blank water through the sampler into the
glass jug- The blank sample was sealed with a Teflon®-lined cap,
labeled, and packed in ice in a plastic foam-insulated chest.
This sample subsequently was analyzed to determine any contamina-
tion contributed by the automatic sampler.
Each large composite (Type 1) sample was collected in a 10-liter
(2.6 gallon) wide-mouth glass jar that had been washed with
detergent and water, rinsed with tap water, rinsed with distilled
water, rinsed with methylene chloride, and air dried at room
temperature in a dust-free environment.
During collection of each Type 1 sample, the wide-mouth glass jar
was packed in ice in a separate plastic foam-insulated container.
After the complete composite sample had been collected, it was
mixed to provide a homogenous mixture, and two 1-liter aliquots
were removed for metals analysis and placed in new labeled plas-
tic 1-liter bottles which had been rinsed with distilled water.
Both of the 1-liter aliquots were preserved by the addition of 5
ml of concentrated nitric acid. The bottles were then sealed,
placed in an iced, insulated chest to maintain the temperature of
4°C (39°F) and shipped by air for metal analyses. These analyses
include atomic absorption spectrophotometry and inductively
coupled argon plasma emission spectroscopy (ICAP).
After removal of the two 1-liter metals aliquots from the compos-
ite sample, the balance of the sample in the glass jar was
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subdivided for analysis of nonvolatile organics, conventional,
and nonconventional parameters. If a portion of this sample was
requested by a plant representative for independent analysis, a
1-liter aliquot was placed in a sample container suppled by the
representative.
Sample Types 2 (cyanide) and 3 (total phenols) were stored in new
bottles which had been iced and labeled; 1-liter clear plastic
bottles for Type 2, and 1-liter amber glass for Type 3. The
bottles had been cleaned by rinsing with distilled water, and the
samples were preserved as described below.
To each Type 2 (cyanide) sample, sodium hydroxide was added as
necessary to elevate the pH to 12 or more (as measured using pH
paper). Where the presence of chlorine (which would decompose
most of the cyanide) was suspected, the sample was tested for
chlorine by using potassium iodide/starch paper. If the paper
turned blue, ascorbic acid crystals were slowly added and dis-
solved until a drop of the sample produced no change in the color
of the test paper. An additional 0.6 gram (0.021 ounce) of
ascorbic acid was added, and the sample bottle was sealed (by a
Teflon®-lined cap), labeled, iced, and shipped for analysis.
To each Type 3 (total phenols) sample, sulfuric acid was added as
necessary to reduce the pH to 4 or less (as measured using pH
paper). The sample bottle was sealed with a Teflon®-lined cap,
labeled, iced, and shipped for analysis.
Each Type 4 (volatile organics) sample was stored in a new 40-ml
glass vial that had been rinsed with tap water and distilled
water, heated to 105°C (221°F) for one hour, and cooled. This
method was also used to prepare the septum and lid for each bot-
tle. Each bottle, when used, was filled to overflowing, sealed
with a Teflon®-faced silicone septum (Teflon® side down), capped,
labeled, and iced. Proper sealing was verified by inverting and
tapping the container to confirm the absence of air bubbles. (If
bubbles were found, the bottle was opened, a few additional drops
of sample were added, and a new seal was installed.) Samples
were labeled, iced to 4°C, and sent for analysis.
A 1-quart wide-mouth glass bottle was used to collect a grab sam-
ple for oil and grease analysis. Because oil tends to form a
film on top of water in quiescent streams, the sample was col-
lected in an area of complete mixing. Sulfuric acid was added as
necessary to reduce the pH to less than 2. The sample bottle was
sealed with a Teflon®-lined cap, labeled, iced to 4°C, and ship-
ped for analysis.
Sample Analysis. Samples were sent by air to laboratories where
inductively coupled argon plasma emission spectroscopy (ICAP) and
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atomic absorption spectrophotometry (AA) analyses were performed.
The samples were analyzed only for metals shown to be significant
in the nonferrous metals manufacturing category or those expected
to consume large amounts of lime. Twenty-one metals were ana-
lyzed by ICAP, and five metals were analyzed by AA, as follows:
Metals Analyzed by ICAP
Aluminum Magnesium
Barium Manganese
Beryllium Molybdenum
Boron Nickel
Cadmium Sodium
Calcium Tin
Chromium Titanium
Cobalt Vanadium
Copper Yttrium
Iron Zinc
Lead
Metals Analyzed by AA
Antimony
Arsenic
Selenium
Silver
Thallium
Mercury was analyzed by cold vapor flameless atomic absorption
spectrophotometry.
Samples also went to laboratories for organics analysis. Due to
their very similar physical and chemical properties, it is
extremely difficult to separate the seven polychlorinated
biphenyls (pollutants 106 to 112) for analytical identification
and quantification. For that reason, the concentrations of the
polychlorinated biphenyls are reported by the analytical labora-
tory in two groups: one group consists of PCB-1242, PCB-1254,
and PCB-1221; the other group consists of PCB-1232, PCB-1248,
PCB-1260, and PCB-1016. For convenience, the first group will be
referred to as PCB-1254 and the second as PCB-1248.
The samples were not analyzed for Pollutant 129, 2, 3, 7, 8-tetra-
chlorodibenzo-p-dioxin (TCDD) because no reference sample was
available to the analytical laboratory.
Three of the five conventional pollutant parameters were selected
for analysis for evaluating treatment system performance. They
are total suspended solids (TSS), oil and grease, and pH. The
other two conventionals, fecal coliform and biochemical oxygen
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demand (BOD), were not analyzed because there is no reason to
believe that fecal matter or oxygen demanding biological mate-
rials would be present. Ammonia, fluoride, and total phenols
(4-AAP) were analyzed for in selected samples if there was reason
to believe they would be present based on the processes used.
While not classified as toxic pollutants, they affect the water
quality. Chemical oxygen demand (COD) and total organic carbon
(TOG) were also selected for analysis for selected samples for
subsequent use in evaluating treatment system performance. Total
dissolved solids (TDS) was analyzed to evaluate the potential for
accumulation of dissolved salts.
In addition, chloride, alkalinity/acidity, total solids, total
phosphorus (as PO^.), and sulf ate were measured to provide data
to evaluate the performance and cost of lime and settle treatment
of certain wastewater streams.
The analytical quantification limits used in evaluation of the
sampling data reflect the accuracy of the analytical methods
used. Below these concentrations, the identification of the
individual compounds is possible, but quantification is diffi-
cult. Pesticides and PCB's can be analytically quantified at
concentrations above 0.005 mg/1, and other organic toxics at
concentrations above 0.010 mg/1. Analytical quantification
limits associated with toxic metals are as follows: 0.100 mg/1
for antimony; 0.10 mg/1 for arsenic; 10 MFL for asbestos; 0.010
mg/1 for beryllium; 0.002 mg/1 for cadmium; 0.005 mg/1 for chro-
mium; 0.009 mg/1 for copper; 0.100 mg/1 for cyanide; 0.02 mg/1
for lead; 0.0001 mg/1 for mercury; 0.005 mg/1 for nickel; 0.010
mg/1 for selenium; 0.020 mg/1 for silver; 0.100 mg/1 for
thallium; and 0.050 mg/1 for zinc.
These detection limits are not the same as published detection
limits for these pollutants by the same analytical methods (40
CFR Part 136 - Guidelines Establishing Test Procedures for the
Analysis of Pollutants; 40 CFR Part 136 - Proposed, 44 FR 69464,
December 3, 1979; 1982 Annual Book of ASTM Standards, Part 31,
Water, ASTM, Philadelphia, PA; Methods for Chemical Analysis of
Water and Wastes, Environmental Monitoring and Support Labora-
tory, Office of Research and Development, U.S. EPA Cincinnati,
OH, March, 1979, EPA-600 4-79-020; Handbook for Monitoring
Industrial Wastewater, U.S. EPA Technology Transfer, August,
1973). The detection limits used were reported with the
analytical data and hence are 'the appropriate limits to apply to
the data. Detection limit variation can occur as a result of a
number of laboratory-specific, equipment-specific, and daily
operator-specific factors. These factors can include day-to-day
differences in machine calibration, variation in stock solutions,
and variation in operators.
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Quality Control. Quality control measures used in performing all
analyses conducted for this program complied with the guidelines
given in "Handbook for Analytical Quality Control in Water and
Wastewater Laboratories" (published by EPA Environmental Monitor-
ing and Support Laboratory, Cincinnati, Ohio, 1976). As part of
the daily quality control program, blanks (including sealed sam-
ples of blank water carried to each sampling site and returned
unopened, as well as samples of blank water used in the field),
standards, and spiked samples were routinely analyzed with actual
samples. As part of the overall program, all analytical instru-
ments (such as balances, spectrophotometers, and recorders) were
routinely maintained and calibrated.
The atomic-absorption spectrophotometer used for metal analysis
was checked to see that it was operating correctly and performing
within expected limits. Appropriate standards were included
after at least every 10 samples. Reagent blanks were also ana-
lyzed for each metal.
WATER USE AND WASTEWATER CHARACTERISTICS
In each of the subcategory supplements, wastewater characteris-
tics corresponding to the subcategories in the nonferrous metals
manufacturing category are presented and discussed. Tables are
presented in Section V of each of the subcategory supplements
which present the sampling program data for raw waste and treated
effluent sampled streams. For those pollutants detected above
analytically quantifiable concentrations in any sample of a given
wastewater stream, the actual analytical data are presented.
Where no data are listed for a specific day of sampling, it indi-
cates that the wastewater samples for the stream were not
collected.
The statistical analysis of data includes some samples measured
at concentrations considered not quantifiable. The base neu-
trals, acid fraction, and volatile organics are considered not
quantifiable at concentrations equal to or less than 0.010 mg/1.
Below this level, organic analytical results are not quantita-
tively accurate; however, the analyses are useful to indicate the
presence of a particular pollutant. Nonquantifiable results are
designated in the tables with an asterisk (double asterisk for
pesticides).
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assumed to be zero. When calculating averages from metal,
cyanide, conventional and nonconventional sampling data, values
reported as less than a certain value were considered as not
quantifiable, and consequently were assigned a value of zero.
118
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SECTION VI
SELECTION OF POLLUTANT PARAMETERS
The Agency has studied nonferrous metals manufacturing waste-
waters to determine the presence or absence of toxic, conven-
tional, and selected nonconventional pollutants. The toxic
pollutants and nonconventional pollutants are subject to BAT
effluent limitations and guidelines. Conventional pollutants are
considered in establishing BPT, BCT, and NSPS limitations.
One hundred and twenty-nine toxic pollutants (known as the 129
priority pollutants) were studied pursuant to the requirements of
the Clean Water Act of 1977 (CWA). These pollutant parameters,
which are listed in Table VI-1 (page 206 ), are members of the 65
pollutants and classes of toxic pollutants referred to in Section
307(a)(1) of the CWA.
From the original list of 129 pollutants, three pollutants have
been deleted in two separate amendments to 40 CFR Subchapter N,
Part 401. Dichlorodifluoromethane and trichlorofluoromethane
were deleted first (46 FR 2266, January 8, 1981) followed by the
deletion of bis-(chloromethyl) ether (46 FR 10723, February 4,
1981). The Agency has concluded that deleting these compounds
will not compromise adequate control over their discharge into
the aquatic environment and that no adverse effects on the
aquatic environment or on human health will occur as a result of
deleting them from the list of toxic pollutants.
Past studies by EPA and others have identified many nontoxic pol-
lutant parameters useful in characterizing industrial wastewaters
and in evaluating treatment process removal efficiencies. For
this reason, a number of nontoxic pollutants were also studied
for the nonferrous metals manufacturing category.
EPA has defined the criteria for the selection of conventional
pollutants (43 FR 32857 January 11, 1980). These criteria are:
1. Generally those pollutants that are naturally occurring,
biodegradable; oxygen-demanding materials, and solids that have
characteristics similar to naturally occurring, biodegradable
substances; or,
2. Include those classes of pollutants that traditionally have
been the primary focus of wastewater control.
The conventional pollutants considered in this rulemaking (total
suspended solids, oil and grease, and pH) traditionally have been
studied to characterize industrial wastewaters. These parameters
121
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impact water quality and are especially useful in evaluating the
effectiveness of some wastewater treatment processes.
Several nonconventional pollutants were also considered in devel-
oping, these regulations. These include aluminum, chemical oxygen
demand (COD), and total organic carbon (TOG). In addition, cal-
cium, chloride, magnesium, alkalinity/acidity, total dissolved
solids, total phosphorus (as PO^.), and sulfate were measured to
provide data to evaluate the cost of chemical precipitation and
sedimentation treatment of certain wastewater streams.
Fluoride, ammonia (Nl^), and total phenols (4-AAP) were also
identified as pollutants for some of the subcategories. Fluoride
compounds are used in the production of primary and secondary
titanium, and secondary uranium and are present in the raw waste-
water of these industries. In the secondary molybdenum and vana-
dium, secondary precious metals, secondary tungsten and cobalt,
secondary uranium, and primary zirconium and hafnium subcatego-
ries, NH3 is used in the process or formed during a process
step. In other subcategories, it has been used for neutraliza-
tion of the wastewater.
RATIONALE FOR SELECTION OF POLLUTANT PARAMETERS
In determining which pollutants to regulate, a pollutant that was
never detected, or that was never found above its analytical
quantification level, was eliminated from consideration. The
analytical quantification level for a pollutant is the minimum
concentration at which that pollutant can be reliably measured.
Below that concentration, the identification of the individual
compounds is possible, but quantification is difficult. For the
toxic pollutants in this study, the analytical quantification
levels are: 0.005 mg/1 for pesticides, PCB's, chromium, and
nickel; 0.010 mg/1 for the remaining organic toxic pollutants and
cyanide, arsenic, beryllium, and selenium; 10 million fibers per
liter (10 MFL) for asbestos; 0.020 mg/1 for lead and silver;
0.009 mg/1 for copper; 0.002 mg/1 for cadmium; and 0.0001 mg/1
for mercury.
These detection limits are not the same as published detection
limits for these pollutants by the same analytical methods. The
detection limits used were reported with the analytical data and
hence are the appropriate limits to apply to the data. Detection
limit variation can occur as a result of a number of laboratory-
specific, equipment-specific, and daily operator-specific
factors. These factors can include day-to-day differences in
machine calibration, variation in stock solutions, and variation
in operators.
122
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Because the analytical standard for TCDD was judged to be too
hazardous to be made generally available, samples were never
analyzed for this pollutant. There is no reason to expect that
TCDD would be present in nonferrous metals manufacturing
wastewaters .
Pollutants which were detected below concentrations considered
achievable by available treatment technology were also eliminated
from further consideration. For the toxic metals, the chemical
precipitation, sedimentation, and filtration technology treata-
bility values , which are presented in Section VII (Table VII-22)
were used. For the toxic organic pollutants detected above their
analytical quantification limit, achievable concentrations for
activated carbon technology were used. These concentrations
represent the most stringent treatment options considered for
pollutant removal.
The pollutant exclusion procedure was applied to the raw waste
data for each subcategory. Detailed specific results are pre-
sented in Section VI of each of the subcategory supplements.
Summary results of selected pollutants for each subcategory are
presented later in this section.
Toxic pollutants remaining after the application of the exclusion
process were then selected for further consideration in estab-
lishing specific regulations.
DESCRIPTION OF POLLUTANT PARAMETERS
The following discussion addresses the pollutant parameters
detected above their analytical quantification limit in any
sample of nonferrous metals manufacturing wastewater. The
description of each pollutant provides the following information:
the source of the pollutant; whether it is a naturally occurring
element, processed metal, or manufactured compound; general phys-
ical properties and the form of the pollutant; toxic effects of
the pollutant in humans and other animals; and behavior of the
pollutant in a POTW at concentrations that might be expected from
industrial discharges.
Acenaphthene ( 1 ) . Acenaphthene ( 1 , 2-d ihydroacenaphthylene , or
1 ,8-ethylene-naphthalene) is a polynuclear aromatic hydrocarbon
(PAH) with molecular weight of 154 and a formula of C
Acenaphthene occurs in coal tar produced during high temperature
coking of coal. It has been detected in cigarette smoke and
gasoline exhaust condensates.
The pure compound is a white crystalline solid at room tempera-
ture with a melting range of 95°C to 97°C and a boiling range of
278°C to 280°C. Its vapor pressure at room temperature is less
123
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than 0.02 mm Hg. Acenaphthene is slightly soluble in water (100
mg/1), but even more soluble in organic solvents such as ethanol,
toluene, and chloroform. Acenaphthene can be oxidized by oxygen
or ozone in the presence of certain catalysts. It is stable
under laboratory conditions.
Acenaphthene is used as a dye intermediate, in the manufacture of
some plastics, and as an insecticide and fungicide.
So little research has been performed on acenaphthene that its
mammalian and human health effects are virtually unknown. The
water quality criterion of 0.02 mg/1 is recommended to prevent
the adverse effects on humans due to the organoleptic properties
of acenaphthene in water.
No detailed study of acenaphthene behavior in a POTW is avail-
able. However, it has been demonstratd that none of the organic
toxic pollutants studied so far can be broken down by biological
treatment processes as readily as fatty acids, carbohydrates, or
proteins. Many of the toxic pollutants have been investigated,
at least in laboratory-scale studies, at concentrations higher
than those expected to be contained by most municipal waste-
waters. General observations relating molecular structure to
ease of degradation have been developed for all of the toxic
organic pollutants.
The conclusion reached by study of the limited data is that bio-
logical treatment produces little or no degradation of acenaph-
thene. No evidence is available for drawing conclusions about
its possible toxic or inhibitory effect on POTW operation.
Its water solubility would allow acenaphthene present in the
influent to pass through a POTW into the effluent. The hydrocar-
bon character of this compound makes it sufficiently hydrophobic
that adsorption onto suspended solids and retention in the sludge
may also be a significant route for removal of acenaphthene from
the POTW.
Acenaphthene has been demonstrated to affect the growth of plants
through improper nuclear division and polyploidal chromosome
number. However, it is not expected that land application of
sewage sludge containing acenaphthene at the low concentrations
which are to be expectd in a POTW sludge would result in any
adverse effects on animals ingesting plants grown in such soil.
Benzene (4). Benzene (CgHg) is a clear, colorless liquid
obtained mainly from petroleum feedstocks by several different
processes. Some is recovered from light oil obtained from coal
carbonization gases. It boils at 80°C and has a vapor pressure
124
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of 100 mm Hg.at 26°C. It is slightly soluble in water (1.8 g/1
at 25°C) and it dissolves in hydrocarbon solvents. Annual U.S.
production is three to four million tons.
Most of the benzene used in the U.S. goes into chemical manufac-
ture. About half of that is converted to ethylbenzene which is
used to make styrene. Some benzene is used in motor fuels.
Benzene is harmful to human health according to numerous pub-
lished studies. Most studies relate effects of inhaled benzene
vapors. These effects include nausea, loss of muscle coordina-
tion, and excitement, followed by depression and coma. Death is
usually the result of respiratory or cardiac failure. Two spe-
cific blood disorders are related to benzene exposure. One of
these, acute myelogenous leukemia, represents a carcinogenic
effect of benzene. However, most human exposure data are based
on exposure in occupational settings and benzene carcinogenisis
is not considered to be firmly established.
Oral administration of benzene to laboratory animals produced
leukopenia, a reduction in mumber of leukocytes in the blood.
Subcutaneous injection of benzene-oil solutions has produced sug-
gestive, but not conclusive, evidence of benzene carcinogenisis.
Benzene demonstrated teratogenic effects in laboratory animals,
and mutagenic effects in humans and other animals.
For maximum protection of human health from the potential carcin-
ogenic effects of exposure to benzene through ingestion of water
and contaminated aquatic organisms, the ambient water concentra-
tion is zero. Concentrations of benzene estimated to result in
additional lifetime cancer risk at levels of 10~7, 10"^, and
10~5 are 0.15 ug/1, 1.5 ug/1, and 15 ug/1, respectively.
Some studies have been reported regarding the behavior of benzene
in a POTW. Biochemical oxidation of benzene under laboratory
conditions, at concentrations of 3 to 10 mg/1, produced 24, 27,
24, and 20 percent degradation in 5, 10, 15, and 20 days, respec-
tively, using unacclimated seed cultures in fresh water. Degra-
dation of 58, 67, 76, and 80 percent was produced in the same
time periods using acclimated seed cultures. Other studies pro-
duced similar results. Based on these data and general conclu-
sions relating molecular structure to biochemical oxidation, it
is expected that biological treatment in a POTW will remove ben-
zene readily from the water. Other reports indicate that most
benzene entering a POTW is removed to the sludge and that influ-
ent concentrations of 1 g/1 inhibit sludge digestion. There is
no information about possible effects of benzene on crops grown
in soils amended with sludge containing benzene.
125
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Carbon Tetrachloride (6). Carbon tetrachloride (CCl^), also
called tetrachloromethane, is a colorless liquid produced primar-
ily by the chlorination of hydrocarbons - particularly methane.
Carbon tetrachloride boils at 77°C and has a vapor pressure of 90
mm Hg. at 20°C. It is slightly soluble in water (0.8 gm/1 at
25°C) and soluble in many organic solvents. Approximately
one-third of a million tons is produced annually in the U.S.
Carbon tetrachloride, which was displaced by perchloroethylene as
a dry cleaning agent in the 1930's, is used principally as an
intermediate for production of chlorofluoromethanes for refriger-
ants, aerosols, and blowing agents. It is also used as a grain
fumigant.
Carbon tetrachloride produces a variety of toxic effects in
humans. Ingestion of relatively large quantities - greater than
5 grams - has frequently proved fatal. Symptoms are burning
sensation in the mouth, esophagus, and stomach, followed by
abdominal pains, nausea, diarrhea, dizziness, abnormal pulse, and
coma. When death does not occur immediately, liver and kidney
damage are usually found. Symptoms of chronic poisoning are not
as well defined. General fatigue, headache, and anxiety have
been observed, accompanied by digestive tract and kidney discom-
fort or pain.
Data concerning teratogenicity and mutagenicity of carbon tetra-
chloride are scarce and inconclusive. However, carbon tetrachlo-
ride has been demonstrated to be carcinogenic in laboratory
animals. The liver was the target organ.
For maximum protection of human health from the potential carcin-
ogenic effects of exposure to carbon tetrachloride through inges-
tion of water and contaminated aquatic organisms, the ambient
water concentration is zero. Concentrations of carbon tetrachlo-
ride estimated to result in additional lifetime cancer risk at
risk levels of 10-7, 10~6, and 10~5 are 0.026 ug/1, 0.26
ug/1, and 2.6 ug/1, respectively.
Data on the behavior of carbon tetrachloride in a POTW are not
available. Many of the toxic organic pollutants have been inves-
tigated, at least in laboratory-scale studies, at concentrations
higher than those expected to be found in most municipal waste-
waters. General observations have been developed relating
molecular structure to ease of degradation for all of the toxic
organic pollutants. The conclusion reached by study of the
limited data is that biological treatment- produces a moderate
degree of removal of carbon tetrachloride in a POTW. No informa-
tion was found regarding the possible interference of carbon
tetrachloride with treatment processes. Based on the water
solubility of carbon tetrachloride, and the vapor pressure of
126
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this compound, it is expected that some of the undegraded carbon
tetrachloride will pass through to the POTW effluent and some
will be volatilized in aerobic processes.
Chlorobenzene (7). Chlorobenzene (CgH^Cl) , also called mono-
chlorobenzene is a clear, colorless, liquid manufactured by the
liquid phase chlorination of benzene over a catalyst. It boils
at 132°C and has a vapor pressure of 12.5 mm Hg at 25°C. It is
almost insoluble in water (0.5 g/1 at 30°C) , but dissolves in
hydrocarbon solvents. U.S. annual production is near 150,000
tons .
Principal uses of Chlorobenzene are as a solvent and as an inter-
mediate for dyes and pesticides. Formerly it was used as an
intermediate for DDT production, but elimination of production of
that compound reduced annual U.S. production requirements for
Chlorobenzene by half.
Data on the threat to human health posed by Chlorobenzene are
limited in number. Laboratory animals, administered large doses
of Chlorobenzene subcutaneously , died as a result of central
nervous system depression. At slightly lower dose rates, animals
died of liver or kidney damage. Metabolic disturbances occurred
also. At even lower dose rates of orally administered chloroben-
zene similar effects were observed, but some animals survived
longer than at higher dose rates. No studies have been reported
regarding evaluation of the teratogenic, mutagenic, or carcino-
genic potential of Chlorobenzene.
For the prevention of adverse effects due to the organoleptic
properties of Chlorobenzene in water the recommended criterion is
0.020 mg/1.
Only limited data are available on which to base conclusions
about the behavior of Chlorobenzene in a POTW. Laboratory
studies of the biochemical oxidation of Chlorobenzene have been
carried out at concentrations greater than those expected to
normally be present in POTW influent. Results showed the extent
of degradation to be 25, 28, and 44 percent after 5, 10, and 20
days, respectively. In another, similar study using a phenol-
adapted culture 4 percent degradation was observed after 3 hours
with a solution containing 80 mg/1. On the basis of these
results and general conclusions about the relationship of molec-
ular structure to biochemical oxidation, it is concluded that
Chlorobenzene remaining, intact is expected to volatilize from the
POTW in aeration processes. The estimated half -life of chloro-
benzene in water based on water solubility, vapor pressure and
molecular weight is 5.8 hours.
1 ,2,4-Trichlorobenzene (8). 1 , 2 ,4-Trichlorobenzene
1,2,4-TCB) is a liquid at room temperature, solidifying to a
127
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crystalline solid at 1 7°C and boiling at 214°C. It is produced
by liquid phase chlorination of benzene in the presence of a
catalyst. Its vapor pressure is 4 mm Hg at 25°C. 1 , 2, 4-TCB is
insoluble in water and soluble in organic solvents. Annual U.S.
production is in the range of 15,000 tons. 1 , 2, 4-TCB is used in
limited quantities as a solvent and as a dye carrier in the tex-
tile industry. It is also used as a heat transfer medium and as
a transfer fluid. The compound can be selectively chlorinated to
1 , 2, 4, 5-tetrachlorobenzene using iodine plus antimony trichloride
as catalyst.
No reports were available regarding the toxic effects of
1 , 2, 4-TCB on humans. Limited data from studies of effects in
laboratory animals fed 1,2, 4-TCB indicate depression of activity
at low doses and predeath extension convulsions at lethal doses.
Metabolic disturbances and liver changes were also observed.
Studies for the purpose of determining teratogenic or mutagenic
properties of 1,2, 4-TCB have not been conducted. No studies have
been made of carcinogenic behavior of 1,2, 4-TCB administered
orally.
For the prevention of adverse effects due to the organoleptic
properties of 1 , 2, 4-trichlorobenzene in water, .the water quality
criterion is 0.013 mg/1.
Data on the behavior of 1,2, 4-TCB in POTW are not available.
However, this compound has been investigated in a laboratory
scale study of biochemical oxidation at concentrations higher
than those expected to be contained by most municipal waste-
waters. Degradations of 0, 87, and 100 percent were observed
after 5, 10, and 20 days, respectively. Using this observation
and general observations relating molecular structure to ease of
degradation for all of the organic priority pollutants , the
conclusion was reached that biological treatment produces a high
degree of removal in POTW.
Hexachlorobenzene (9). Hexachlorobenzene (CfcH^) is a non-
flammable crystalline substance which is virtually insoluble in
water. However, it is soluble in benzene, chloroform, and ether.
Hexachlorobenzene (HCB) has a density of 2.044 g/ml. It melts at
231 °C and boils at 323 to 326°C. Commercial production of HCB in
the U.S. was discontinued in 1976, though it is still generated
as a by-product of other chemical operations. In 1972, an esti-
mated 2,425 tons of HCB were produced in this way.
Hexachlorobenzene is used as a fungicide to control fungal
diseases in cereal grains. The main agricultural use of HCB is
on wheat seed intended solely for planting. HCB has been used as
an impurity in other pesticides. It is used in industry as a
plasticizer for polyvinyl chloride as well as a flame retardant.
128
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HCB is also used as a starting material for the production of
pentachlorophenol which is marketed as a wood preservative.
Hexachlorobenzene can be harmful to human health as was seen in
Turkey from 1955 to 1959. Wheat that had been treated with HCB
in preparation for planting was consumed as food. Those people
affected by HCB developed cutanea tarda porphyria, the symptoms
of which included blistering and epidermolysis of the exposed
parts of the body, particularly the face and the hands. These
symptoms disappeared after consumption of HCB contaminated bread
was discontinued. However, the HCB which was stored in body fat
contaminated maternal milk. As a result of this, at least 95
percent of the infants feeding on this milk died. The fact that
HCB remains stored in body fat after exposure has ended presents
an additional problem. Weight loss may result in a dramatic
redistribution of HCB contained in fatty tissue. If the stored
levels of HCB are high, adverse effects might ensue.
Limited testing suggests that hexachlorobenzene is not terato-
genic or mutagenic. However, two animal studies have been con-
ducted which indicate that HCB is a carcinogen. HCB appears to
have multipotential carcinogenic activity; the incidence of hepa-
tomas, haemangioendotheliomas and thyroid adenomas was signifi-
cantly inceased in animals exposed to HCB by comparison to con-
trol animals.
For maximum protection of human health from the potential carcin-
ogenic effects of exposure to hexachlorobenzene through ingestion
of water and contaminated aquatic organisms, the ambient water
concentration is zero. Concentrations of HCB estimated to result
in additional lifetime cancer risk at levels of 10"^, 10~^,
and 10~5 are 7. 2 x 10~8 mg/1, 7.2 x 10~6 mg/1, and 7. 2 x
10~6 mg/1, respectively. If contaminated aquatic organisms
alone are consumed, excluding the consumption of water, the water
concentration should be less than 7.4 x 10"*" mg/1 to keep the
increased lifetime cancer risk below 10~5. Available data show
that adverse effects on aquatic life occur at concentrations
higher than those cited for human health risks.
No detailed study of hexachlorobenzene behavior in POTW is avail-
able. However, general observations relating molecular structure
to ease of degradation have been developed for all of the organic
priority pollutants. The conclusion reached by study of the
limited data is that biological treatment produces little or no
degradation of hexachlorobenzene. No evidence is available for
drawing conclusions regarding its possible toxic or inhibitory
effect on POTW operations.
1,2-Dichloroethane (10). 1,2-Dichloroethane is a halogenated
aliphatic used in the production of tetraethyl lead and vinyl
chloride, as an industrial solvent, and as an intermediate in the
129
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production of other organochlprine compounds. Some chlorinated
ethanes have been found in drinking waters, natural waters,
aquatic organisms, and foodstuffs. Research indicates that they
may have mutagenic and carcinogenic properties.
1 ,1 ,1-Trichloroethane (1j_). 1 ,1 ,1-Trichloroethane is one of the
two possible trichlorethanes. It is manufactured by hydrochlori-
nating vinyl chloride to 1,1-dichloroethane which is then chlori-
nated to the desired product. 1,1,1-Trichloroethane is a liquid
at room temperature with a vapor pressure of 96 mm Hg at 20°C and
a boiling point of 74°C. Its formula is CCl^CH^. It is
slightly soluble in water (0.48 g/1) and is very soluble in
organic solvents. U.S. annual production is greater than one-
third of a million tons.
1,1,1-Trichloroethane is used as an industrial solvent and
degreasing agent.
Most human toxicity data for 1,1,1-trichloroethane relates to
inhalation and dermal exposure routes. Limited data are avail-
able for determining toxicity of ingested 1,1,1-trichloroethane,
and those data are all for the compound itself, not solutions in
water. No data are available regarding its toxicity to fish, and
aquatic organisms. For the protection of human health from the
toxic properties of 1,1,1-trichloroethane ingested through the
comsumption of water and fish, the ambient water criterion is
15.7 mg/1. The criterion is based on bioassays for possible
carcinogenicity.
No detailed study of 1 ,1 ,1-trichloroethane behavior in a POTW is
available. However, it has been demonstrated that none of the
toxic organic pollutants of this type can be broken down by bio-
logical treatment processes as readily as fatty acids, carbohy-
drates, or proteins.
Biochemical oxidation of many of the toxic organic pollutants has
been investigated, at least in laboratory scale studies, at con-
centrations higher than commonly expected in municipal waste-
water. General observations relating molecular structure to ease
of degradation have been developed for all of these pollutants.
The conclusion reached by study of the limited data is that
biological treatment produces a moderate degree of degradation of
1,1,1-trichloroethane. No evidence is available for drawing con-
clusions about its possible toxic or inhibitory effect on POTW
operation. However, for degradation to occur, a fairly constant
input of the compound would be necessary.
Its water solubility would allow 1,1,1-trichloroethane, present
in the influent and not biodegradable, to pass through a POTW
into the effluent. One factor which has received some attention,
130
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but no detailed study, is the volatilization of the lower molecu-
lar weight organics from a POTW. If 1,1,1-trichloroethane is not
biodegraded, it will volatilize during aeration processes in the
POTW.
Hexachloroethane (12). Hexachloroethane (CC13CC13), also
called perchloroethane is a white crystalline solid with a
camphor-like odor. It is manufactured from tetrachloroethylene,
and is a minor product in many industrial chlorination processes
designed to produce lower chlorinated hydrocarbons. Hexachloro-
ethane sublimes at 185°C and has a vapor pressure of about 0.2 mm
Hg at 20°C. It is insoluble in water (50 mg/1 at 22°C) and solu-
ble in some organic solvents.
Hexachloroethane can be used in lubricants designed to withstand
extreme pressure. It is used as a plasticizer for cellulose
esters, and as a pesticide. It is also used as a retarding agent
in fermentation, as an accelerator in the rubber industry, and in
pyrotechnic and smoke devices.
Hexachloroethane is considered to be toxic to humans by ingestion
and inhalation. In laboratory animals liver and kidney damage
have been observed. Symptoms in humans exposed to hexachloro-
ethane vapor include severe eye irritation and vision impairment.
Based on studies on laboratory animals, hexachloroethane is
considered to be carcinogenic.
For the maximum protection of human health from the potential
carcinogenic effects of exposure to hexachloroethane through
ingestion of water and contaminated aquatic organisms, the
ambient water concentration is zero. Concentrations of hexa-
chloroethane estimated to result in additional lifetime cancer
risks at levels of 10~7, 10~6, and 10~5 are 0.059 ug/1,
0.59 ug/1, and 5.9 ug/1, respectively.
Data on the behavior of hexachloroethane in POTW are not availa-
ble. Many of the organic priority pollutants have been investi-
gated, at least in laboratory scale studies, at concentrations
higher than those expected to be contained by most municipal
wastewaters. General observations have been developed relating
molecular structure to ease of degradation for all of the organic
priority pollutants. The conclusion reached by study of the
limited data is that biological treatment produces little or no
removal of hexachloroethane in POTW. The lack of water solubil-
ity and the expected affinity of hexachloroethane for solid
particles lead to the expectation that this compound will be
removed to the sludge in POTW. No information was found regard-
ing possible uptake of hexachloroethane by plants grown on soils
amended with hexachloroethane-bearing sludge.
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1,1-Dichloroethane (13). 1,1-Dichloroethane, C2H^Cl2, also
called ethylidene dichloride and ethylidene chloride, is a color-
less liquid manufactured by reacting hydrogen chloride with vinyl
chloride in 1,1-dichloroethane solution in the presence of a
catalyst. However, it is reportedly not manufactured commer-
cially in the U.S. 1,1-Dichloroethane boils at 57°C and has a
vapor pressure of 182 mm Hg at 20°C. It is slightly soluble in
water (5.5 g/1 at 20°C) and very soluble in organic solvents.
1,1-Dichloroethane is used as an extractant for heat-sensitive
substances and as a solvent for rubber and silicone grease.
1,1-Dichloroethane is less toxic than its isomer (1 , 2-dichloro-
ethane), but its use as an anaesthetic has been discontinued
because of marked excitation of the heart. It causes central
nervous system depression in humans. There are insufficient data
to derive water quality criteria for 1,1-dichloroethane.
Data on the behavior of 1,1-dichloroethane in a POTW are not
available. Many of the toxic organic pollutants have been
investigated, at least in laboratory scale studies, at concen-
trations higher than those expected to be contained by most
municipal wastewaters. General observations have been developed
relating molecular structure to ease of degradation for all of
the toxic organic pollutants. The conclusion reached by study of
the limited data is that biological treatment produces only a
moderate removal of 1,1-dichloroethane in a POTW by degradation.
The high vapor pressure of 1,1-dichloroethane is expected to
result in volatilization of some of the compound from aerobic
processes in a POTW. Its water solubility will result in some of
the 1,1-dichloroethane which enters the POTW leaving in the
effluent from the POTW.
1,1,2-Trichloroethane (14). 1,1,2-Trichloroethane is one of the
two possible trichloroethanes and is sometimes called ethane tri-
chloride or vinyl trichloride. It is used as a solvent for fats,
oils, waxes, and resins, in the manufacture of 1,1-dichloro-
ethylene, and as an intermediate in organic synthesis.
1,1,2-Trichloroethane is a clear, colorless liquid at room tem-
perature with a vapor pressure of 16.7 mm Hg at 20°G, and a boil-
ing point of 113°C. It is insoluble in water and very soluble in
organic solvents. The formula is CHC12CH2C1.
Human toxicity data for 1,1,2-trichloroethane do not appear in
the literature. The compound does produce liver and kidney dam-
age in laboratory animals after intraperitoneal administration.
No literature data were found concerning teratogenicity or muta-
genicity of 1,1,2-trichloroethane. However, mice treated with
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1 ,1 ,2-trichloroethane showed increased incidence of hepatocellu-
lar carcinoma. Although bioconcentration factors are not avail-
able for 1 ,1 ,2-trichloroethane in fish and other freshwater
aquatic organisms, it is concluded on the basis of octanol-water
partition coefficients that bioconcentration does occur.
For the maximum protection of human health from the potential
carcinogenic effects of exposure to 1 ,1 ,2-trichloroethane through
ingestion of water and contaminated aquatic organisms, the ambi-
ent water concentration is zero. Concentrations of this compound
estimated to result in additional lifetime cancer risks at risk
levels of 10"7, 10~6, and 10~5 are 0.06 ug/1, 0.6 ug/1, and
6 ug/1, respectively. If contaminated aquatic organisms alone
are consumed, excluding the consumption of water, the water con-
centration should be less than 0.418 mg/1 to keep the increased
lifetime cancer risk below 10~5. Available data show that
adverse effects on aquatic life occur at concentrations higher
than those cited for human health risks.
No detailed study of 1 ,1 ,2-trichloroethane behavior in a POTW is
available. However, it is reported that small amounts are formed
by chlorination processes and that this compound persists in the
environment (greater than two years) and it is not biologically
degraded. This information is not completely consistent with the
conclusions based on laboratory scale biochemical oxidation
studies and relating molecular structure to ease of degradation.
That study concluded that biological treatment in a POTW will
produce moderate removal of 1 ,1 ,2-trichloroethane.
The lack of water solubility and the relatively high vapor
pressure may lead to removal of this compound from a POTW by
volatilization.
2,4,6-Trichlprophenol (21). 2 ,4,6-Trichlorophenol (
abbreviated here to 2,4,6-TCP) is a colorless, crystalline solid
at room temperature. It is prepared by the direct chlorination
of phenol. 2,4,6-TCP melts at 68° C and is slightly soluble in
water (0.8 gm/1 at 25° C). This phenol does not produce a color
with 4-aminoantipyrene, and therefore does not contribute to the
nonconventional pollutant parameter "Total Phenols." No data
were found on production volumes.
2,4,6-TCP is used as a fungicide, bactericide, glue and wood pre-
servative, and for antimildew treatment. It is also used for the
manufacture of 2 ,3 ,4 ,6-tetrachlorophenol and pentachlorophenol.
No data were found on human toxicity effects of 2,4,6-TCP.
Reports of studies with laboratory animals indicate that
2,4,6-TCP produced convulsions when injected interperitoneally.
Body temperature was elevated also. The compound also produced
inhibition of ATP production in isolated rat liver mitochondria,
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increased mutation rates in one strain of bacteria, and produced
a genetic change in rats. No studies on teratogenicity were
found. Results of a test for carcinogenicity were inconclusive.
For the prevention of adverse effects due to the organoleptic
properties of 2,4,6-trichlorophenol in water, the water quality
criterion is 0.100 mg/1.
Although no data were found regarding the behavior of 2,4,6-TCP
in a POTW, studies of the biochemical oxidation of the compound
have been made at laboratory scale at concentrations higher than
those normally expected in municipal wastewaters. Biochemical
oxidation of 2,4,6-TCP at 100 mg/1 produced 23 percent degrada-
tion using a phenol-adapted acclimated seed culture. Based on
these results, biological treatment in a POTW is expected to pro-
duce a moderate degree of degradation. Another study indicates
that 2,4,6-TCP may be produced in a POTW by chlorination of
phenol during normal chlorination treatment.
Para-chloro-meta-cresol (22). Para-chloro-meta-cresol
(ClCyl^OH) is thought to be a 4-chloro-3-methyl-phenol
(4-chloro-meta-cresol, or 2-chloro-5-hydroxy-toluene), but is
also used by some authorities to refer to 6-chloro-3-methyl-
phenol (6-chloro-meta-cresol, or 4-chloro-3-hydroxy-toluene),
depending on whether the chlorine is considered to be para to the
methyl or to the hydroxy group. It is assumed for the purposes
of this document that the subject compound is 2-chloro-5-hydroxy-
toluene. This compound is a colorless crystalline solid melting
at 66 to 68°C. It is slightly soluble in water (3.8 gm/1) and
soluble in organic solvents. This phenol reacts with 4-amino-
antipyrene to give a colored product and therefore contributes to
the nonconventional pollutant parameter designated "Total
Phenols." No information on manufacturing methods or volumes
produced was found.
Para-chloro-meta cresol (abbreviated here as PCMC) is marketed as
a microbicide, and was proposed as an antiseptic and disinfectant
more than 40 years ago. It is used in glues, gums, paints, inks,
textiles, and leather goods. PCMC was found in raw wastewaters
from the die casting quench operation from one subcategory of
foundry operations.
Although no human toxicity data are available for PCMC, studies
on laboratory animals have demonstrated that this compound is
toxic when administered subcutaneously and intravenously. Death
was preceded by severe muscle tremors. At high dosages kidney
damage occurred. On the other tiand, an unspecified isomer of
chlorocresol, presumed to be PCMC, is used at a concentration of
0.15 percent to preserve muicous heparin, a natural product
administered intravenously as an anticoagulant. The report does
not indicate the total amount of PCMC typically received. No
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information was found regarding possible teratogenicity, or
carcinogenicity of PCMC.
Two reports indicate that PCMC undergoes degradation in biochemi-
cal oxidation treatments carried out at concentrations higher
than are expected to be encountered in POTW influents. One study
showed 50 percent degradation in 3.5 hours when a phenol-adapted
acclimated seed culture was used with a solution of 60 mg/1 PCMC.
The other study showed 100 percent degradation of a 20 mg/1 solu-
tion of PCMC in two weeks in an aerobic activated sludge test
system. No degradation of PCMC occurred under anaerobic con-
ditions.
Chloroform (23). Chloroform, CHC13, also called trichloro-
methane, is a colorless liquid manufactured commercially by
chlorination of methane. Careful control of conditions maximizes
chloroform production, but other products must be separated.
Chloroform boils at 61°C and has a vapor pressure of 200 mm Hg at
25°C. It is slightly soluble in water (8.22 g/1 at 20°C) and
readily soluble in organic solvents.
Chloroform is used as a solvent and to manufacture refrigerants,
Pharmaceuticals, plastics, and anaesthetics. It is seldom used
as an anaesthetic.
Toxic effects of chloroform on humans include central nervous
system depression, gastrointestinal irritation, liver and kidney
damage, and possible cardiac sensitization to adrenalin. Carcin-
ogenicity has been demonstrated for chloroform on laboratory
animals.
For the maximum protection of human health from the potential
carcinogenic effects of exposure to chloroform through ingestion
of water and contaminated aquatic organisms, the ambient water
concentration is zero. Concentrations of chloroform estimated to
result in additional lifetime cancer risks at the levels of
10-7, 10-°, and 10~5 were 0.021 ug/1, 0.21 ug/1, and 2.1
ug/1, respectively.
No data are available regarding the behavior of chloroform in a
POTW. However, the biochemical oxidation of this compound was
studied in one laboratory scale study at concentrations higher
than those expected to be contained by most municipal waste-
waters. After 5, 10, and 20 days no degradation of chloroform
was observed. The conclusion reached is that biological treat-
ment produces little or no removal by degradation of chloroform
in a POTW.
The high vapor pressure of chloroform is expected to result in
volatilization of the compound from aerobic treatment steps in a
POTW. Remaining chloroform is expected to pass through into the
POTW effluent.
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2-Chlorophenol (24). 2-Chlorophenol (C1C6H4OH), also called
ortho-chlorophenol, is a colorless liquid at room temperature,
manufactured by direct chlorination of phenol followed by distil-
lation to separate it from the other principal product, 4-chloro-
phenol. 2-Chlorophenol solidifies below 7°C and boils at 176°C.
It is soluble in water (28.5 gm/1 at 20°C) and soluble in several
types of organic solvents. This phenol gives a strong color with
4-aminoantipyrene and therefore contributes to the nonconven-
tional pollutant parameter "Total Phenols." Production statis-
tics could not be found. 2-Chlorophenol is used almost exclu-
sively as a chemical intermediate in the production of pesticides
and dyes. Production of some phenolic resins uses
2-chlorophenol.
Very few data are available on which to determine the toxic
effects of 2-chlorophenol on humans. The compound is more toxic
to laboratory mammals when administered orally than when adminis-
tered subcutaneously or intravenously. This affect is attributed
to the fact that the compound is almost completely in the
un-ionized state at the low pH of the stomach and hence is more
readily absorbed into the body. Initial symptoms are restless-
ness and increased respiration rate, followed by motor weakness
and convulsions induced by noise or touch. Coma follows. Fol-
lowing, lethal doses, kidney, liver, and intestinal damage were
observed. No studies were found which addressed the teratogenic-
ity or mutagenicity of 2-chlorophenol. Studies of 2-chlorophenol
as a promoter of carcinogenic activity of other carcinogens were
conducted by dermal application. Results do not bear a determin-
able relationship to results of oral administration studies.
For the prevention of adverse effects due to the organoleptic
properties of 2-chlorophenol in water, the criterion is 0.0003
mg/1.
Data on the behavior of 2-chlorophenol in a POTW are not avail-
able. However, laboratory scale studies have been conducted at
concentrations higher than those expected to be found in munici-
pal wastewaters. At 1 mg/1 of 2-chlorophenol, an acclimated
culture produced 100 percent degradation by biochemical oxidation
after 15 days. Another study showed 45, 70, and 79 percent
degradation by biochemical oxidation after 5, 10, and 20 days,
respectively. The conclusion reached by the study of these
limited data, and general observations on all toxic organic
pollutants relating molecular structure to ease of biochemcial
oxidation, is that 2-chlorophenol is removed to a high degree or
completely by biological treatment in a POTW. Undcgraded
2-chlorophenol is expected to pass through a POTW into the efflu-
ent because of the water solubility. Some 2-chlorophenol is also
expected to be generated by chlorination treatments of POTW
effluents containing phenol.
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1 1-Dichloroethylene (29). 1,1-Dichloroethylene (1,1-DCE), also
called vinylidene chloride, is a clear colorless liquid manufac-
tured by dehydrochlorination of 1,1,2-trichloroethane. 1,1-DCE
has the formula CC12CH2. It has a boiling point of 32°C, and
a vapor pressure of 591 mm Hg at 25°C. 1,1-DCE is slightly solu-
ble in water (2.5 mg/1) and is soluble in many organic solvents.
U.S. production is in the range of hundreds of thousands of tons
annually.
1,1-DCE is used as a chemical intermediate and for copolymer
coatings or films. It may enter the wastewater of an industrial
facility as the result of decomposition of 1,1,1-trichloro-
ethylene used in degreasing operations, or by migration from
vinylidene chloride copolymers exposed to the process water.
Human toxicity of 1,1-DCE has not been demonstrated; however, it
is a suspected human carcinogen. Mammalian toxicity studies have
focused on the liver and kidney damage produced by 1,1-DCE.
Various changes occur in those organs in rats and mice ingesting
1,1-DCE.
For the maximum protection of human health from the potential
carcinogenic effects of exposure to 1,1-dichloroethylene through
ingestion of water and contaminated aquatic organisms, the ambi-
ent water concentration is zero. The concentration of 1,1-DCE
estimated to result in an additional lifetime cancer risk of 1 in
100,000 is 0.0013 mg/1.
Under laboratory conditions, dichloroethylenes have been shown to
be toxic to fish. The primary effect of acute toxicity of the
dichloroethylenes is depression of the central nervous system.
The octanol/water partition coefficident of 1,1-DCE indicates it
should not accumulate significantly in animals.
The behavior of 1,1-DCE in a POTW has not been studied. However,
its very high vapor pressure is expected to result in release of
significant percentages of this material to the atmosphere in any
treatment involving aeration. Degradation of dichloroethylene in
air is reported to occur, with a half-life of eight weeks.
Biochemical oxidation of many of the toxic organic pollutants has
been investigated in laboratory scale studies at concentrations
higher than would normally be expected in municipal wastewaters.
General observations relating molecular structure to ease of
degradation have been developed for all of these pollutants. The
conclusion reached by study of the limited data is that biologi-
cal treatment produces little or no degradation of 1,1-dichloro-
ethylene. No evidence is available for drawing conclusions about
the possible toxic or inhibitory effect of 1,1-DCE on POTW opera-
tion. Because of water solubility, 1,1-DCE which is not volatil-
ized or degraded is expected to pass through a POTW. Very little
1,1-DCE is expected to be found in sludge from a POTW.
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1,2-trans-Dlchloroethylene (30). 1,2-Dichloroethylene (1,2-
trans-DCE) is a clear, colorless liquid with the formula
CHC1CHC1. 1,2-trans-DCE is produced in mixture with the cis-
isomer by chlorination of acetylene. The cis-isomer has dis-
tinctly different physical properties. Industrially, the mixture
is used rather than the separate isomers. 1,2-trans-DCE has a
boiling point of 48°C, and a vapor pressure of 234 mm Hg at 25°C.
The principal use of 1,2-dichloroethylene (mixed isomers) is to
produce vinyl chloride. It is used as a lead scavenger in gaso-
line, general solvent, and for synthesis of various other organic
chemicals. When it is used as a solvent, 1,2-trans-DCE can enter
wastewater streams.
Although 1,2-trans-DCE is thought to produce fatty degeneration
of mammalian liver, there are insufficient data on which to base
any ambient water criterion.
In the reported toxicity test of 1 , 2-tr_ans_-DCE on aquatic life,
the compound appeared to be about half as toxic as the other
dichloroethylene (1,1-DCE) on the toxic pollutants list.
The behavior of 1,2-trans-DCE in a POTW has not been studied.
However, its high vapor pressure is expected to result in release
of a significant percentage of this compound to the atmosphere in
any treatment involving aeration. Degradation of the dichloro-
ethylenes in air is reported to occur, with a half-life of eight
weeks.
Biochemical oxidation of many of the toxic organic pollutants has
been investigated in laboratory scale studies at concentrations
higher than would normally be expected in municipal wastewaters.
General observations relating molecular structure to ease of
degradation have been developed for all of these pollutants. The
conclusion reached by the study of the limited data is that
biochemical oxidation produces little or no degradation of
1 , 2-_trans-dichloroethylene. No evidence is available for drawing
conclusions about the possible toxic or inhibitory effect of
1,2-trans-dichloroethylene on POTW operation. It is expected
that its low molecular weight and degree of water solubility will
result in 1,2-trans-DCE passing through a POTW to the effluent if
it is not degraded or volatilized. Very little 1,2-trans-DCE is
expected to be found in sludge from a POTW.
2,4-Dichlorophenol (31). 2,4-Dichlorophenol, a white, low melt-
ing solid, melts at 45 C. It is soluble in alcohol and carbon
tetrachloride and slightly soluble in water. This compound is
moderately toxic by ingestion and is a strong irritant to tissue.
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2,4-Dimethylphenol (34). 2,4-Dimethylphenol (2,4-DMP), also
called 2,4-xylenol, is a colorless, crystalline solid at room
temperature (25°C), but melts at 27°C to 28°C. 2,4-DMP is
slightly soluble in water and, as a weak acid, is soluble in
alkaline solutions. Its vapor pressure is less than 1 mm Hg at
room temperature.
2,4-DMP (CgN^QO) is a natural product, occurring in coal and
petroleum sources. It is used commercially as an intermediate
for manufacture of pesticides, dye stuffs, plastics and resins,
and surfactants. It is found in the water runoff from asphalt
surfaces. It can find its way into the wastewater of a manufac-
turing plant from any of several adventitious sources.
Analytical procedures specific to this compound are used for its
identification and quantification in wastewaters. This compound
does not contribute to "Total Phenols" determined by the
4-aminoantipyrene method.
Three methylphenol isomers (cresols) and six dimethylphenol
isomers (xylenols) generally occur together in natural products,
industrial processes, commercial products, and phenolic wastes.
Therefore, data are not available for human exposure to 2,4-DMP
alone. In addition to this, most mammalian tests for toxicity of
individual dimethylphenol isomers have been conducted with
isomers other than 2,4-DMP.
In general, the mixtures of phenol, methylphenols, and dimethy1-
phenols contain compounds which produced acute poisoning in
laboratory animals. Symptoms were difficult breathing, rapid
muscular spasms, disturbance of motor coordination, and asym-
metrical body position. In a 1977 National Academy of Science
publication the conclusion was reached that, "In view of the
relative paucity of data on the mutagenicity, carcinogenicity,
teratogenicity, and long term oral toxicity of 2,4-dimethyl-
phenol, estimates of the effects of chronic oral exposure at low
levels cannot be made with any confidence." No ambient water
quality criterion can be set at this time. In order to protect
public health, exposure to this compound should be minimized as
soon as possible.
Toxicity data for fish and freshwater aquatic life are limited;
however, in reported studies of 2,4-dimethylphenol at concen-
trations as high as 2 mg/1 no adverse effects were observed.
The behavior of 2,4-DMP in a POTW has not been studied. As a
weak acid, its behavior may be somewhat dependent on cne pH of
the influent to the POTW. However, over the normal limited range
of POTW pH, little effect of pH would be expected.
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Biological degradability of 2,4-DMP as determined in one study,
showed 94.5 percent removal based on chemical oxygen demand
(COD). Thus, substantial removal is expected for this compound.
Another study determined that persistence of 2,4-DMP in the envi-
ronment is low, and thus any of the compound which remained in
the sludge or passed through the POTW into the effluent would be
degraded within moderate length of time (estimated as two months
in the report).
2,4-Dinitrotoluene (35). 2,4-Dinitrotoluene [ (N02) 2C6H3CH3-'' a
yellow crystalline compound, is manufactured as a co-product with
the 2,6-isomer by nitration of nitrotoluene. It melts at 71°C.
2,4-Dinitrotoluene is insoluble in water (0.27 g/1 at 22°C) and
soluble in a number of organic solvents. Production data for the
2,4-isomer alone are not available. The 2,4- and 2,6-isomers are
manufactured in an 80:20 or 65:35 ratio, depending on the process
used. Annual U.S. commercial production is about 150 thousand
tons of the two isomers. Unspecified amounts are produced by the
U.S. government and further nitrated to trinitrotoluene (TNT) for
military use. The major use of the dinitrotoluene mixture is for
production of toluene diisocyanate used to make polyurethanes.
Another use is in production of dyes tuffs.
The toxic effect of 2,4-dinitrotoluene in humans is primarily
methemoglobinemia (a blood condition hindering oxygen transport
by the blood). Symptoms depend on severity of the disease, but
include cyanosis, dizziness, pain in joints, headache, and loss
of appetite in workers inhaling the compound. Laboratory animals
fed oral doses of 2,4-dinitrotoluene exhibited many of the same
symptoms. Aside from the effects in red blood cells, effects are
observed in the nervous system and testes.
Chronic exposure to 2,4-dinitrotoluene may produce liver damage
and reversible anemia. No data were found on teratogenicity of
this compound. Mutagenic data are limited and are regarded as
confusing. Data resulting from studies of carcinogenicity of
2,4-dinitrotoluene point to a need for further testing for this
property.
For the maximum protection of human health from the potential
carcinogenic effects of exposure to 2,4-dinitrotoluene through
ingestion of water and contaminated aquatic organisms, the ambi-
ent water concentration is zero. Concentrations of 2,4-
dinitrotoluene estimated to result in additional lifetime cancer
risk at risk levels of 1Q-"7, 10~6, and 105 are 7.4 ug/1,
74 ug/1, and 740 ug/1, respectively.
Data on the behavior of 2,4-dinitrotoluene in a POTW are not
available. However, biochemical oxidation of 2,4-dinitrophenol
was investigated on a laboratory scale. At 100 mg/1 of 2,4-
dinitrotoluene, a concentration considerably higher than that
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expected in municipal wastewaters, biochemical oxidation by an
acclimated, phenol-adapted seed culture produced 52 percent
degradation in three hours. Based on this limited information
and general observations relating molecular structure to ease of
degradation for all the toxic organic pollutants, it was con-
cluded that biological treatment in a POTW removes 2,4-dinitro-
toluene to a high degree or completely. No information is
available regarding possible interference by 2,4-dinitrotoluene
in POTW treatment processes, or on the possible detrimental
effect on sludge used to ammend soils in which food crops are
grown.
Ethylbenzene (38). Ethylbenzene (CgHjQ) is a colorless,
flammable liquid manufactured commercially from benzene and
ethylene. Approximately half of the benzene used in the U.S.
goes into the manufacture of more than three million tons of
ethylbenzene annually. Ethylbenzene boils at 136°C and has a
vapor pressure of 7 mm Hg at 20°C. It is slightly soluble in
water (0.14 g/1 at 15°C) and is very soluble in organic solvents.
About 98 percent of the ethylbenzene produced in the U.S. goes
into the production of styrene, much of which is used in the
plastics and synthetic rubber industries. Ethylbenzene is a con-
stituent of xylene mixtures used as diluents in the paint indus-
try, agricultural insecticide sprays, and gasoline blends.
Although humans are exposed to ethylbenzene from a variety of
sources in the environment, little information on effects of
ethylbenzene in man or animals is available. Inhalation can
irritate eyes, affect the respiratory tract, or cause vertigo.
In laboratory animals ethylbenzene exhibited low toxicity. There
are no data available on teratogenicity, mutagenicity, or car-
cinogenicity of ethylbenzene.
Criteria are based on data derived from inhalation exposure
limits. For the protection of human health from the toxic prop-
erties of ethylbenzene ingested through water and contaminated
aquatic organisms, the ambient water quality criterion is 1.1
mg/1.
The behavior of ethylbenzene in a POTW has not been studied in
detail. Laboratory scale studies of the biochemical oxidation of
ethylbenzene at concentrations greater than would normally be
found in municipal wastewaters have demonstrated varying degrees
of degradation. In one study with phenol-acclimated seed
cultures, 27 percent degradation was observed in a half day at
250 mg/1 ethylbenzene. Another study at unspecified conditions
showed 32, 38, and 45 percent degradation after 5, 10, and 20
days, respectively. Based on these results and general observa-
tions relating molecular structure of degradation, the conclu-
sion is reached that biological treatment produces only mod-
erate removal of ethylbenzene in a POTW by degradation.
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Other studies suggest that most of the ethybenzene entering a
POTW is removed from the aqueous stream to the sludge. The
ethylbenzene contained in the sludge removed from the POTW may
volatilize.
Fluoranthene (39). Fluoranthene (1,2-benzacenaphthene) is one of
the compounds called polynuclear aromatic hydrocarbons (PAH). A
pale yellow solid at room temperature, it melts at 11 1°C and has
a negligible vapor pressure at 25°C. Water solubility is low
(0.2 mg/1). Its molecular formula is C^HIQ.
Fluoranthene, along with many other PAH's, is found throughout
the environment. It is produced by pyrolytic processing of
organic raw materials, such as coal and petroleum, at high tem-
perature (coking processes). It occurs naturally as a product of
plant biosyntheses. Cigarette smoke contains fluoranthene.
Although it is not used as the pure compound in industry, it has
been found at relatively higher concentrations (0.002 mg/1) than
most other PAH's in at least one industrial effluent. Further-
more, in a 1977 EPA survey to determine levels of PAH in U.S.
drinking water supplies, none of the 110 samples analyzed showed
any PAH other than fluoranthene.
Experiments with laboratory animals indicate that fluoranthene
presents a relatively low degree of toxic potential from acute
exposure, including oral administration. Where death occurred,
no information was reported concerning target organs or specific
cause of death.
There is no epidemiological evidence to prove that PAH in
general, and fluoranthene, in particular, present in drinking
water are related to the development of cancer. The only studies
directed toward determining carcinogenicity of fluoranthene have
been skin tests on laboratory animals. Results of these tests
show that fluoranthene has no activity as a complete carcinogen
(i.e., an agent which produces cancer when applied by itself),
but exhibits significant cocarcinogenicity (i.e., in combination
with a carcinogen, it increases the carcinogenic activity).
Based on the limited animal study data, and following an estab-
lished procedure, the ambient water quality criterion for fluor-
anthene alone (not in combination with other PAH) is determined
to be 200 mg/1 for the protection of human health from its toxic
properties.
There are no data on the chronic effects of fluoranthene on
freshwater organisms. One saltwater invertebrate shows chronic
toxicity at concentrations below 0.016 mg/1. For some fresh-
water fish species the concentrations producing acute toxicity
are substantially higher, but data are very limited.
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Results of studies of the behavior of fluoranthene in conven-
tional sewage treatment processes found in a POTW have been
published. Removal of fluoranthene during primary sedimentation
was found to be 62 to 66 percent (from an initial value of
0.00323 to 0.04435 mg/1 to a final value of 0.00122 to 0.0146
mg/1), and the removal was 91 to 99 percent (final values of
0.00028 to 0.00026 mg/1) after biological purification with
activated sludge processes.
A review was made of data on biochemical oxidation of many of the
toxic organic pollutants investigated in laboratory scale studies
at concentrations higher than would normally be expected in
municipal wastewaters. General observations relating molecular
structure to ease of degradation have been developed for all of
these pollutants. The conclusion reached by study of the limited
data is that biological treatment produces little or no degrada-
tion of fluoranthene. The same study, however, concludes that
fluoranthene would be readily removed by filtration and oil-water
separation and other methods which rely on water insolubility, or
adsorption on other particulate surfaces. This latter conclusion
is supported by the previously cited study showing, significant
removal by primary sedimentation.
No studies were found to give data on either the possible inter-
ference of fluoranthene with POTW operation, or the persistence
of fluoranthene in sludges or POTW effluent waters. Several
studies have documented the ubiquity of fluoranthene in the envi-
ronment and it cannot be readily determined if this results from
persistence of anthropogenic fluoranthene or the replacement of
degraded fluoranthene by natural processes such as biosynthesis
in plants.
Methylene Chloride (44). Methylene chloride, also called dichlo-
romethane (Ct^C^), is a colorless liquid manufactured by
chlorination of methane or methyl chloride followed by separation
from the higher chlorinated methanes formed as co-products.
Methylene chloride boils at 40°C, and has a vapor pressure of 362
mm Hg at 20°C. It is slightly soluble in water (20 g/1 at 20°C),
and very soluble in organic solvents. U.S. annual production is
about 250,000 tons.
Methylene chloride is a common industrial solvent found in
insecticides, metal cleaners, paint, and paint and varnish
removers.
Methylfeue chloride is not generally regarded as highly toxic to
humans. Most human toxicity data are for exposure by inhalation.
Inhaled methylene chloride acts as a central nervous system
depressant. There is also evidence that the compound causes
heart failure when large amounts are inhaled.
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Methylene chloride does produce mutation in tests for this
effect. In addition, a bioassay recognized for its extremely
high sensitivity to strong and weak carcinogens produced results
which were marginally significant. Thus potential carcinogenic
effects of methylene chloride are not confirmed or denied, but
are under continuous study. Difficulty in conducting and inter-
preting the test results from the low boiling point (40°C) of
methylene chloride which increases the difficulty of maintaining
the compound in growth media during incubation at 37°C; and from
the difficulty of removing all impurities, some of which might
themselves be carcinogenic.
For the protection of human health from the toxic properties of
methylene chloride ingested through water and contaminated
aquatic organisms, the ambient water criterion is 0.002 mg/1.
The behavior of methylene chloride in a POTW has not been studied
in any detail. However, the biochemical oxidation of this com-
pound was studied in one laboratory scale study at concentrations
higher than those expected to be contained by most municipal
wastewaters. After five days no degradation of methylene chlo-
ride was observed. The conclusion reached is that biological
treatment produces little or no removal by degradation of
methylene chloride in a POTW.
The high vapor pressure of methylene chloride is expected to
result in volatilization of the compound from aerobic treatment
steps in a POTW. It has been reported that methylene chloride
inhibits anaerobic processes in a POTW. Methylene chloride that
is not volatilized in the POTW is expected to pass through into
the effluent.
Dichlorobromomethane (48). This compound is a halogenated ali-
phatic. Research has been shown that halomethanes have carcino-
genic properties, and exposure to this compound may have adverse
effects on human health.
Cjhlorodibromomethane (51). This compound is a halogenated ali-
phatic.Research has been shown that halomethanes have carcino-
genic properties, and exposure to this compound may have adverse
effects on human health.
Isophorone (54). Isophorone is an industrial chemical produced
at a level of tens of millions of pounds annually in the U.S.
The chemical name for isophorone is 3,5,5-trimethyl-2-cyclohexen-
1-one and it is also known as trimethyl cyclohexanone and
isoacetophorone. The formula is C^^CCH-j^O. Normally,
it is produced as the gamma isomer; technical grades contain
about 3 percent of the beta isomer (3,5,5-trimethyl-3-cyclohexen-
1-one). The pure gamma isomer is a water-white liquid, with
vapor pressure less than 1 mm Hg at room temperature, and a
boiling point of 215.2°C. It has a camphor- or peppermint-like
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odor and yellows upon standing. It is slightly soluble (12 mg/1)
in water and dissolves in fats and oils.
Isophorone is synthesized from acetone and is used commercially
as a solvent or cosolvent for finishes, lacquers, polyvinyl and
nitrocellulose resins, pesticides, herbicides, fats, oils, and
gums. It is also used as a chemical feedstock.
Because isophorone is an industrially used solvent, most toxicity
data are for inhalation exposure. Oral administration to labora-
tory animals in two different studies revealed no acute or
chronic effects during 90 days, and no hematological or patholog-
ical abnormalities were reported. Apparently, no studies have
been completed on the carcinogenicity of isophorone.
Isophorone does undergo bioconcentration in the lipids of aquatic
organisms and fish.
Based on subacute data, the ambient water quality criterion for
isophorone ingested through consumption of water and fish is set
at 460 mg/1 for the protection of human health from its toxic
properties.
Studies of the effects of isophorone on fish and aquatic organ-
isms reveal relatively low toxicity, compared to some other toxic
pollutants.
The behavior of isophorone in a POTW has not been studied. How-
ever, the biochemical oxidation of many of the toxic organic
pollutants has been investigated in laboratory scale studies at
concentrations higher than would normally be expected in munici-
pal wastewaters. General observations relating molecular struc-
ture to ease of degradation have been developed for all of these
pollutants. The conclusion reached by the study of the limited
data is that biochemical treatment in a POTW produces moderate
removal of isophorone. This conclusion is consistent with the
findings of an experimental study of microbiological degradation
of isophorone which showed about 45 percent oxidation in 15 to 20
days in domestic wastewater, but only 9 percent in salt water.
No data were found on the persistence of isophorone in sewage
sludge.
Naphthalene (55). Naphthalene is an aromatic hydrocarbon with
two orthocondensed benzene rings and a molecular formula of
CIQ^S* As such it is properly classed as a polynuclear
aromatic hydrocarbon (PAH). Pure naphthalene is a white crystal-
line solid melting at 80°C. For a solid, it has a relatively
high vapor pressure (0.05 mm Hg at 20°C), and moderate water
solubility (19 mg/1 at 20°C). Napthalene is the most abundant
single component of coal tar. Production is more than a third of
a million tons annually in the U.S. About three fourths of the
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production is used as feedstock for phthalic anhydride manufac-
ture. Most of the remaining production goes into manufacture of
insecticide, dyestuffs, pigments, and pharmaceuticals. Chlori-
nated and partially hydrogenated naphthalenes are used in some
solvent mixtures. Naphthalene is also used as a moth repellent.
Naphthalene, ingested by humans, has reportedly caused vision
loss (cataracts), hemolytic anemia, and occasionally, renal dis-
ease. These effects of naphthalene ingestion are confirmed by
studies on laboratory animals. No carcinogenicity studies are
available which can be used to demonstrate carcinogenic activity
for naphthalene. Naphthalene does bioconcentrate in aquatic
organisms.
For the protection of human health from the toxic properties of
naphthalene ingested through water and through contaminated
aquatic organisms, the ambient water criterion is determined to
be 143 mg/1.
Only a limited number of studies have been conducted to determine
the effects of naphthalene on aquatic organisms. The data from
those studies show only moderate toxicity.
Naphthalene has been detected in sewage plant effluents at con-
centrations up to 0.022 mg/1 in studies carried out by the U.S.
EPA. Influent levels were not reported. The behavior of naph-
thalene in a POTW has not been studied. However, recent studies
have determined that naphthalene will accumulate in sediments at
100 times the concentration in overlying water. These results
suggest that naphthalene will be readily removed by primary and
secondary settling in a POTW, if it is not biologically degraded.
Biochemical oxidation of many of the toxic organic pollutants has
been investigated in laboratory scale studies at concentrations
higher than would normally be expected in municipal wastewaters.
General observations relating molecular structure to ease of
degradation have been developed for all of these pollutants. The
conclusion reached by study of the limited data is that biologi-
cal treatment produces a high removal by degradation of naphthal-
ene. One recent study has shown that microorganisms can degrade
naphthalene, first to a dihydro compound, and ultimately to car-
bon dioxide and water.
Nitrobenzene (56). Nitrobenzene (CgH5N02), also called
nitrobenzol and oil of mirbane, is a pale yellow, oily liquid,
manufactured by reacting benzene with nitric acid and sulfuric
acid. Nitrobenzene boils at 210°C and has a vapor pressure of
0.34 mm Hg at 25°C. It is slightly soluble in water (1.9 g/1 at
20°C), and is miscible with most organic solvents. Estimates of
annual U.S production vary widely, ranging from 100 to 350
thousand tons.
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Almost the entire volume of nitrobenzene produced (97 percent) is
converted to aniline, which is used in dyes, rubber, and medici-
nals. Other uses for nitrobenzene include: solvent for organic
synthesis, metal polishes, shoe polish, and perfume.
The toxic effects of ingested or inhaled nitrobenzene in humans
are related to its action in blood: methemoglobinemia and
cyanosis. Nitrobenzene administered orally to laboratory animals
caused degeneration of heart, kidney, and liver tissue; paraly-
sis; and death. Nitrobenzene has also exhibited teratogenicity
in laboratory animals, but studies conducted to determine muta-
genicity or carcinogenicity did not reveal either of these
properties.
For the prevention of adverse effets due to the organoleptic
properties of nitrobenzene in water, the criterion is 0.030 mg/1.
Data on the behavior of nitrobenzene in POTW are not available.
However, laboratory scale studies have been conducted at con-
centrations higher than those expected to be found in municipal
wastewaters. Biochemical oxidation produced no degradation after
5, 10, and 20 days. A second study also reported no degradation
after 28 hours, using an acclimated, phenol-adapted seed culture
with nitrobenzene at 100 mg/1. Based on these limited data, and
on general observations relating molecular structure to ease of
biological oxidation, it is concluded that little or no removal
of nitrobenzene occurs during biological treatment in POTW. The
low water solubility and low vapor pressure of nitrobenzene lead
to the expectation that nitrobenzene will be- removed from POTW in
the effluent and by volatilization during aerobic treatment.
2-Nitrophenol (57). 2-Nitrophenol (N02C6H40H), also called
ortho-nitrophenol, is a light yellow crystalline soli.d, manufac-
tured commercially by hydrolysis of 2-chloro-nitrobenzene with
aqueous sodium hydroxide. 2-Nitrophenol melts at 45°C and has a
vapor pressure of 1 mm Hg at 49°C. 2-Nitrophenol is slightly
soluble in water (2.1 g/1 at 20°C) and soluble in organic sol-
vents. This phenol does not react to give a color with 4-amino-
antipyrene, and therefore does not contribute to the nonconven-
tional pollutant parameter "Total Phenols." U.S. annual produc-
tion is 5,000 to 8,000 tons.
The principle use of ortho-nitrophenol is to synthesize ortho-
aminophenol, ortho-nitroanisole, and other dyestuff intermedi-
ates .
The toxic effects of 2-nitrophcr.ol on humans have not been exten-
sively studied. Data from experiments with laboratory animals
indicate that exposure to this compound causes kidney and liver
damage. Other studies indicate that the compound acts directly
on cell membranes, and inhibits certain enzyme systems in vitro.
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No information regarding potential teratogencity was found.
Available data indicate that this compound does not pose a
mutagenic hazard to humans. Very limited data for 2-nitrophenol
do not reveal potential carcinogenic effects.
The available data base is insufficient to establish an ambient
water criterion for protection of human health from exposure to
2-nitrophenol. No data are available on which to evaluate the
adverse effects of 2-nitrophenol on aquatic life.
Data on the behavior of 2-nitrophenol in POTW were not available
However, laboratory-scale studies have been conducted at concen-
trations higher than those expected to be found in municipal
wastewater. Biochemical oxidation using adapted cultures from
various sources produced 95 percent degradation in three to six
days in one study. Similar results were reported for other
studies. Based on these data, and general observations relating
molecular structure to ease of biological oxidation, it is
expected that 2-nitrophenol will be biochemically oxidized to a
lesser extent than domestic sewage by biological treatment in
POTWs .
4-Nitrophenol (58). 4-Nitrophenol (NC^CgH^OH) , also called
parani trophenol , Ts a colorless to yellowish crystalline solid
manufactured commercially by hydrolysis of 4-chloro-nitrobenzene
with aqueous sodium hydroxide. 4-Nitrophenol melts at 114°C.
Vapor pressure is not cited in the usual sources. 4-Nitrophenol
is slightly soluble in water (15 g/1 at 25°C) and soluble in
organic solvents. This phenol does not react to give a color
with 4-aminoantipyrene, and therefore does not contribute to the
nonconventional pollutant parameter "Total Phenols." U.S. annual
production is about 20,000 tons.
Paranitrophenol is used to prepare phenetidine, acetaphenetidine ,
azo and sulfur dyes, photochemicals , and pesticides.
The toxic effects of 4-nitrophenol on humans have not been exten-
sively studied. Data from experiments with laboratory animals
indicate that exposure to this compound results in methemoglobi-
nemia (a metabolic disorder of blood), shortness of breath, and
stimulation followed by depression. Other studies indicate that
the compound acts directly on cell membranes, and inhibits cer-
tain enzyme systems in vitro . No information regarding potential
teratogenicity was found. Available data indicate that this
compound does not pose a mutagenic hazard to humans. Very
limited data for 4-nitrophenol do not reveal potential carcino-
genic effects, although the compound has been selected by the
National Cancer Institute for testing under the Carcinogenic
Bioassay Program.
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No U.S. standards for exposure to 4-nitrophenol in ambient water
have been established.
Data on the behavior of 4-nitrophenol in a POTW are not avail-
able. However, laboratory scale studies have been conducted at
concentrations higher than those expected to be found in munici-
pal wastewaters. Biochemical oxidation using adapted cultures
from various sources produced 95 percent degradation in three to
six days in one study. Similar results were reported for other
studies. Based on these data, and on general observations
relating molecular structure to ease of biological oxidation, it
is concluded that complete or nearly complete removal of
4-nitrophenol occurs during biological treatment in a POTW.
2,4,-Dinitrophenol (59). 2, 4-Dinitrophenol (CgH^^OO , a
yellow crystalline solid, is manufactured commercially by
hydrolysis of 2, 4-dinitro-1 -chlorobenzene with sodium hydroxide.
2, 4-Dinitrophenol sublimes at 114°C. Vapor pressure is not cited
in usual sources. It is slightly soluble in water (7.0 g/1 at
25°C) and soluble in organic solvents. This phenol does not
react with 4-aminoantipyrene and therefore does not contribute to
the nonconventional pollutant parameter "Total Phenols." U.S.
annual production is about 500 tons.
2, 4-Dinitrophenol is used to manufacture sulfur and azo dyes,
photochemicals , explosives, and pesticides.
The toxic effects of 2, 4-dinitrophenol in humans is generally
attributed to their ability to uncouple oxidative phosphoryla-
tion. In brief, this means that sufficient 2, 4-dinitrophenol
short-circuits cell metabolism by preventing utilization of
energy provided by respiration and glycolysis. Specific symp-
toms are gastrointestinal disturbances, weakness, dizziness,
headache, and loss of weight. More acute poisoning includes
symptoms such as: burning thirst, agitation, irregular breath-
ing, and abnormally high fever. This compound also inhibits
other enzyme systems; and acts directly on the cell membrane,
inhibiting chloride permeability. Ingestion of 2, 4-dinitrophenol
also causes cataracts in humans.
Based on available data it appears unlikely that 2, 4-dinitro-
phenol poses a teratogenic hazard to humans. Results of studies
of mutagenic activity of this compound are inconclusive as far as
humans are concerned. Available data suggest that 2, 4-dinitro-
phenol does not possess carcinogenic properties.
To protect human health from the adverse effects of 2, 4-dinitro-
phenol ingested in contaminated water and fish, the suggested
water quality criterion is 0.0686 mg/1 .
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Data on the behavior of 2,4-dinitrophenol in a POTW are not
available. However, laboratory scale studies have been conducted
at concentrations higher than those expected to be found in
municipal wastewaters. Biochemical oxidation using a phenol-
adapted seed culture produced 92 percent degradation in 3.5
hours. Similar results were reported for other studies. Based
on these data, and on general observations relating molecular
structure to ease of biological oxidation, it is concluded that
complete or nearly complete removal of 2,4-dinitrophenol occurs
during biological treatment in a POTW.
4.6-Dinitro-o-cresol (60). 4,6-Dinitro-o-cresol (DNOC) is a
yellow crystalline solid derived from o-cresol. DNOC melts at
85.8°C and has a vapor pressure of 0.000052 mm Hg at 20°C. DNOC
is sparingly soluble in water (100 mg/1 at 20°C), while it is
readily soluble in alkaline aqueous solutions, ether, acetone,
and alcohol. DNOC is produced by sulfonation of o-cresol
followed by treatment with nitric acid.
DNOC is used primarily as a blossom thinning agent on fruit trees
and as a fungicide, insecticide, and miticide on fruit trees dur-
ing the dormant season. It is highly toxic to plants in the
growing stage. DNOC is not manufactured in the U.S. as an agri-
cultural chemical. Imports of DNOC have been decreasing recently
with only 30,000 pounds being imported in 1976.
While DNOC is highly toxic to plants, it is also very toxic to
humans and is considered to be one of the more dangerous agricul-
tural pesticides. The available litrature concerning humans
indicates that DNOC may be absorbed in acutely toxic amounts
through the respiratory and gastrointestinal tracts and through
the skin, and that it accumulates in the blood. Symptoms of
poisoning include profuse sweating, thirst, loss of weight, head-
ache, malaise, and yellow staining to the skin, hair, sclera, and
conj unctiva.
There is no evidence to suggest that DNOC is teratogenic, muta-
genic, or carcinogenic. The effects of DNOC in the human due to
chronic exposure are basically the same as those effects result-
ing from acute exposure. Although DNOC is considered a cumula-
tive poison in humans, cataract formation is the only chronic
effect noted in any human or experimental animal study. It is
believed that DNOC accumulates in the human body and that toxic
symptoms may develop when blood levels exceed 20 mg/kg.
For the protection of human health from the toxic properties of
dinitro-o-cresol ingested through water and contaminated aquatic
organisms, the ambient water criterion is determined to be 0.0134
mg/1. If contaminated aquatic organisms alone are consumed,
excluding the consumption of water, the ambient water criterion
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is determined to be 0.765 mg/1. No data are available on which
to evaluate the adverse effects of 4,6-dinitro-o-cresol on
aquatic life.
Some studies have been reported regarding the behavior of DNOC in
POTW. Biochemical oxidation of DNOC under laboratory conditions
at a concentration of 100 mg/1 produced 22 percent degradation in
3.5 hours, using acclimated phenol adapted seed cultures. In
addition, the nitro group in the number 4 (para) position seems
to impart a destablilizing effect on the molecule. Based on
these data and general conclusions relating molecular structure
to biochemical oxidation, it is expected that 4,6-dinitro-o-
cresol will be biochemically oxidized to a lesser extent than
domestic sewage by biological treatment in POTW.
N-nitrpsodiphenylamine (62). N-nitrosodiphenylamine
[(CgH5)2NNO],also called nitrous diphenylamide, is a
yellow crystalline solid manufactured by nitrosation of diphenyl-
amine. It melts at 66°C and is insoluble in water, but soluble
in several organic solvents other than hydrocarbons. Production
in the U.S. has approached 1,500 tons per year. The compound is
used as a retarder for rubber vulcanization and as a pesticide
for control of scorch (a fungus disease of plants).
N-nitroso compounds are acutely toxic to every animal species
tested and are also poisonous to humans. N-nitrosodiphenylamine
toxicity in adult rats lies in the mid range of the values for 60
N-nitroso compounds tested. Liver damage is the principal toxic
effect. N-nitrosodiphenylamine, unlike many other N-nitroso-
amines, does not show mutagenic activity. N-nitrosodiphenylamine
has been reported by several investigations to be non-carcino-
genic. However, the compound is capable of trans-nitrosation and
could thereby convert other amines to carcinogenic N-nitroso-
amines. Sixty-seven of 87 N-nitrosoamines studied were reported
to have carcinogenic activity. No water quality criterion have
been proposed for N-nitrosodiphenylamine.
No data are available on the behavior of N-nitrosodiphenylamine
in a POTW. Biochemical oxidation of many of the toxic organic
pollutants have been investigated, at least in laboratory scale
studies, at concentrations higher than those expected to be con-
tained in most municipal wastewaters. General observations have
been developed relating molecular structure to ease of degrada-
tion for all the toxic organic pollutants. The conclusion
reached by study of the limited data is that biological treatment
produces little or no removal of N-nitrosodiphenylamine in a
POTW. No information is available regarding possible interfer-
ence by N-nitrosodiphenylamine in POTW processes, or on the
possible detrimental effect on sludge used to amend soils in
which crops are grown. However, no interference or detrimental
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effects are expected because N-nitroso compounds are widely dis-
tributed in the soil and water environment, at low concentra-
tions, as a result of microbial action on nitrates and
nitrosatable compounds.
Pentachlorophenol (64). Pentachlorophenol (C^C^OH) is a
white crystalline solid produced commercially by chlorination of
phenol or polychlorophenols. U.S. annual production is in excess
of 20,000 tons. Pentachlorophenol melts at 190°C and is slightly
soluble in water (14 mg/1). Pentachlorophenol is not detected by
the 4-amino antipyrene method.
Pentachlorophenol is a bactericide and fungicide and is used for
preservation of wood and wood products. It is competitive with
creosote in that application. It is also used as a preservative
in glues, starches, and photographic papers. It is an effective
algicide and herbicide.
Although data are available on the human toxicity effects of pen-
tachlorophenol, interpretation of data is frequently uncertain.
Occupational exposure observations must be examined carefully
because exposure to pentachlorophenol is frequently accompanied
by exposure to other wood preservatives. Additionally, experi-
mental results and occupational exposure observations must be
examined carefully to make sure that observed effects are pro-
duced by the pentachlorophenol itself and not by the by-products
which usually contaminate pentachlorophenol.
Acute and chronic toxic effects of pentachlorophenol in humans
are similar; muscle weakness, headache, loss of appetite,
abdominal pain, weight loss, and irritation of skin, eyes, and
respiratory tract. Available literature indicates that penta-
chlorophenol does not accumulate in body tissues to any signifi-
cant extent. Studies on laboratory animals of distribution of
the compound in body tissues showed the highest levels of penta-
chlorophenol in liver, kidney, and intestine, while the lowest
levels were in brain, fat, muscle, and bone.
Toxic effects of pentachlorophenol in aquatic organisms are much
greater at pH 6 where this weak acid is predominantly in the
undissociated form than at pH 9 where the ionic form predomi-
nates. Similar results were observed in mammals where oral
lethal doses of pentachlorophenol were lower when the compound
was administered in hydrocarbon solvents (un-ionized form) than
when it was administered as the sodium salt (ionized form) in
water.
There appear to be no significant teratogenic, mutagenic, or car-
cinogenic effects of pentachlorophenol.
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For the protection of human health from the toxic properties of
pentachlorophenol ingested through water and through contaminated
aquatic organisms, the ambient water quality criterion is deter-
mined to be 0.140 mg/1.
Only limited data are available for reaching conclusions about
the behavior of pentachlorophenol in a POTW. Pentachlorophenol
has been found in the influent to a POTW. In a study of one POTW
the mean removal was 59 percent over a seven day period. Trickl-
ing filters removed 44 percent at the influent pentachlorophenol,
suggesting that biological degradation occurs. The same report
compared removal of pentachlorophenol at the same plant and two
additional POTW facilities on a later date and obtained values of
4.4, 19.5, and 28.6 percent removal, the last value being for the
plant which was 59 percent removal in the original study. Influ-
ent concentrations of pentachlorophenol ranged from 0.0014 to
0.0046 mg/1. Other studies, including the general review of data
relating molecular structure to biological oxidation, indicate
that pentachlorophenol is not removed by biological treatment
processes in a POTW. Anaerobic digestion processes are inhibited
by 0.4 mg/1 pentachlorophenol.
The low water solubility and low volatility of pentachlorophenol
lead to the expectation that most of the compound will remain in
the sludge in a POTW. The effect on plants grown on land treated
with pentachlorophenol-containing sludge is unpredictable.
Laboratory studies show that this compound affects crop germina-
tion at 5.4 mg/1. However, photodecomposition of pentachloro-
phenol occurs in sunlight. The effects of the various breakdown
products which may remain in the soil were not found in the
literature .
Phenol (65) . Phenol, also called hydroxy benzene and carbolic
acid, is a clear, colorless, hygroscopic, deliquescent, crystal-
line solid at room temperature. Its melting point is 43°C and
its vapor pressure at room temperature is 0.35 mm Hg. It is very
soluble in water (67 gm/1 at 16°C) and can be dissolved in ben-
zene, oils, and petroleum solids. Its formula is
Although a small percent of the annual production of phenol is
derived from coal tar as a naturally occurring product, most of
the phenol is synthesized. Two of the methods are fusion of ben-
zene sulfonate with sodium hydroxide, and oxidation of cumene
followed by cleavage with a catalyst. Annual production in the
U.S. is in excess of one million tons. Phenol is generated dur-
ing distillation of wood and the microbiological decomposition of
organic matter in the mammalian intestinal tract.
Phenol is used as a disinfectant, in the manufacture of resins,
dyestuffs, and in pharmaceuticals, and in the photo processing
industry. In this discussion, phenol is the specific compound
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which is separated by methylene chloride extraction of an acidi-
fied sample and identified and quantified by GC/MS. Phenol also
contributes to the "Total Phenols," discussed elsewhere which are
determined by the 4-AAP colorimetric method.
Phenol exhibits acute and sub-acute toxicity in humans and labor-
atory animals. Acute oral doses of phenol in humans cause sudden
collapse and unconsciousness by its action on the central nervous
system. Death occurs by respiratory arrest. Sub-acute oral
doses in mammals are rapidly absorbed and quickly distributed to
various organs, then cleared from the body by urinary excretion
and metabolism. Long term exposure by drinking phenol contami-
nated water has resulted in a statistically significant increase
in reported cases of diarrhea, mouth sores, and burning of the
mouth. In laboratory animals, long term oral administration at
low levels produced slight liver and kidney damage. No reports
were found regarding carcinogenicity of phenol administered
orally - all carcinogenicity studies were skin test.
For the protection of human health from phenol ingested through
water and through contaminated aquatic organisms, the concen-
tration in water should not exceed 3.4 mg/1.
Fish and other aquatic organisms demonstrated a wide range of
sensitivities to phenol concentration. However, acute toxicity
values were at moderate levels when compared to other toxic
organic pollutants.
Data have been developed on the behavior of phenol in a POTW.
Phenol is biodegradable by biota present in a POTW. The ability
of a POTW to treat phenol-bearing influents depends upon acclima-
tion of the biota and the constancy of the phenol concentration.
It appears that an induction period is required to build up the
population of organisms which can degrade phenol. Too large a
concentration will result in upset or pass though in the POTW,
but the specific level causing upset depends on the immediate
past history of phenol concentrations in the influent. Phenol
levels as high as 200 mg/1 have been treated with 95 percent
removal in a POTW, but more or less continuous presence of phenol
is necessary to maintain the population of microorganisms that
degrade phenol.
Phenol which is not degraded is expected to pass through the POTW
because of its very high water solubility. However, in a POTW
where chlorination is practiced for disinfection of the POTW
effluent, chlorination of phenol may occur. The products of that
reaction may be toxic pollutants.
The EPA has developed data on influent and effluent concentra-
tions of total phenols in a study of 103 POTW facilities. How-
ever, the analytical procedure was the 4-AAP method mentioned
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earlier and not the GC/MS method specifically for phenol.
Discussion of the study, which of course includes phenol, is
presented under the pollutant heading "Total Phenols."
Phthalate Esters (66-71). Phthalic acid, or 1,2-benzene-
dicarboxylic acid,is one of three isomeric benzenedicarboxylic
acids produced by the chemical industry. The other two isomeric
forms are called isophthalic and terephthalic acids. The formula
for all three acids is C6H4(COOH)2« Some esters of
phthalic acid are designated as toxic pollutants. They will be
discussed as a group here, and specific properties of individual
phthalate esters will be discussed afterwards.
Phthalic acid esters are manufactured in the U.S. at an annual
rate in excess of one billion pounds. They are used as plasti-
cizers - primarily in the production of polyvinyl chloride (PVC)
resins. The most widely used phthalate plasticizer is bis
(2-ethylhexyl) phthalate (66) which accounts for nearly one-third
of the phthalate esters produced. This particular ester is com-
monly referred to as dioctyl phthalate (OOP) and should not be
confused with one of the less used esters, di-n-octyl phthalate
(69), which is also used as a plasticizer. In addition to these
two isomeric dioctyl phthalates, four other esters, also used
primarily as plasticizers, are designated as toxic pollutants.
They are: butyl benzyl phthalate (67), di-n-butyl phthalate
(68), diethyl phthalate (70), and dimethyl phthalate (71).
Industrially, phthalate esters are prepared from phthalic anhy-
dride and the specific alcohol to form the ester. Some evidence
is available suggesting that phthalic acid esters also may be
synthesized by certain plant and animal tissues. The extent to
which this occurs in nature is not known.
Phthalate esters used as plasticizers can be present in concen-
trations up to 60 percent of the total weight of the PVC plastic.
The plasticizer is not linked by primary chemical bonds to the
PVC resin. Rather, it is locked into the structure of intermesh-
ing polymer molecules and held by van der Waals forces. The
result is that the plasticizer is easily extracted. Plasticizers
are responsible for the odor associated with new plastic toys or
flexible sheet that has been contained in a sealed package.
Although the phthalate esters are not soluble or are only very
slightly soluble in water, they do migrate into aqueous solutions
placed in contact with the plastic. Thus, industrial facilities
with tank linings, wire and cable coverings, tubing, and sheet
flooring of PVC are expected to discharge some phthalate esters
in their raw waste. In addition to their use as plasticizers,
phthalate esters are used in lubricating oils and pesticide car-
riers. These also can contribute to industrial discharge of
phthalate esters.
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From the accumulated data on acute toxicity in animals, phtha-
late esters may be considered as having a rather low order of
toxicity. Human toxicity data are limited. It is thought that
the toxic effects of the esters is most likely due to one of the
metabolic products, in particular the monoester. Oral acute tox-
icity in animals is greater for the lower molecular weight esters
than for the higher molecular weight esters.
Orally administered phthalate esters generally produced enlarging
of liver and kidney, and atrophy of testes in laboratory animals.
Specific esters produced enlargement of heart and brain, spleen-
itis, and degeneration of central nervous system tissue.
Subacute doses administered orally to laboratory animals produced
some decrease in growth and degeneration of the testes. Chronic
studies in animals showed similar effects to those found in acute
and subacute studies, but to a much lower degree. The same
organs were enlarged, but pathological changes were not usually
detected.
A recent study of several phthalic esters produced suggestive but
not conclusive evidence that dimethyl and diethyl phthalates have
a cancer liability. Only four of the six toxic pollutant esters
were included in the study. Phthalate esters do bioconcentrate
in fish. The factors, weighted for relative consumption of
various aquatic and marine food groups, are used to calculate
ambient water quality criteria for four phthalate esters. The
values are included in the discussion of the specific esters.
Studies of toxicity of phthalate esters in freshwater and salt
water organisms are scarce. A chronic toxicity test with bis(2-
ethylhexyl) phthalate showed that significant reproductive
impairment occurred at 0.003 mg/1 in the freshwater crustacean,
Daphnia magna. In acute toxicity studies, saltwater fish and
organisms showed sensitivity differences of up to eight-fold to
butyl benzyl, diethyl, and dimethyl phthalates. This suggests
that each ester must be evaluated individually for toxic effects.
The behavior of phthalate esters in a POTW has not been studied.
However, the biochemical oxidation of many of the toxic organic
pollutants has been investigated in laboratory scale studies at
concentrations higher than would normally be expected in munici-
pal wastewaters. Three of the phthalate esters were studed.
Bis(2-ethylhexyl) phthalate was found to be degraded slightly or
not at all and its removal by biological treatment in a POTW is
expected to be slight or zero. Di-n-butyl phthalate and diethyl
phthalate were degraded to a moderate degree and their removal by
biological treatment in a POTW is expected to occur to a moderate
degree. Using these data and other observations relating molecu-
lar structure to ease of biochemical degradation of other toxic
organic pollutants, the conclusion was reached that butyl benzyl
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phthalate and dimethyl phthalate would be removed in a POTW to a
moderate degree by biological treatment. On the same basis, it
was concluded that di-n-octyl phthalate would be removed to a
slight degree or not at all. An EPA study of seven POTW facili-
ties revealed that for all but di-n-octyl phthalate, which was
not studied, removals ranged from 62 to 87 percent.
No information was found on possible interference with POTW oper-
ation or the possible effects on sludge by the phthalate esters.
The water insoluble phthalate esters - butyl benzyl and di-n-
octyl phthalate - would tend to remain in sludge, whereas the
other four toxic pollutant phthalate esters with water solubili-
ties ranging from 50 mg/1 to 4.5 mg/1 would probably pass through
into the POTW effluent.
Bis(2-ethylhexyl) Phthalate (66). In addition to the general
remarks and discussion on phthalate esters, specific information
on bis(2-ethylhexyl) phthalate is provided. Little information
is available about the physical properties of bis(2-ethylhexyl)
phthalate. It is a liquid boiling at 387°C at 5 mm Hg and is
insoluble in water. Its formula is CgH^COOCgHi y) o.
This toxic pollutant constitutes about one-third of the phthalate
ester production in the U.S. It is commonly referred to as
dioctyl phthalate, or OOP, in the plastics industry where it is
the most extensively used compound for the plasticization of
polyvinyl chloride (PVC). Bis(2-ethylhexyl) phthalate has been
approved by the FDA for use in plastics in contact with food.
Therefore, it may be found in wastewaters coming in contact with
discarded plastic food wrappers as well as the PVC films and
shapes normally found in industrial plants. This toxic pollutant
is also a commonly used organic diffusion pump oil, where its low
vapor pressure is an advantage.
For the protection of human health from the toxic properties of
bis(2-ethylhexyl) phthalate ingested through water and through
contaminated aquatic organisms, the ambient water quality criter-
ion is determined to be 15 mg/1. If contaminated aquatic organ-
isms alone are consumed, excluding the consumption of water, the
ambient water criteria is determined to be 50 mg/1.
Although the behavior of bis(2-ethylhexyl) phthalate in a POTW
has not been studied, biochemical oxidation of this toxic pollu-
tant has been studied on a laboratory scale at concentrations
higher than would normally be expected in municipal wastewater.
In fresh water with a non-acclimated seed culture no biochemical
oxidation was observed after 5, 10, and 20 days. However, with
an acclimated seed culture, biological oxidation occurred to the
extents of 13, 0, 6, and 23 percent of theoretical after 5, 10,
15, and 20 days, respectively. Bis(2-ethylhexyl) phthalate
concentrations were 3 to 10 mg/1. Little or no removal of
bis(2-ethylhexyl) phthalate by biological treatment in a POTW is
expected.
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Butyl Benzyl Phthalate (67). In addition to the general remarks
and discussion on phthalate esters, specific information on butyl
benzyl phthalate is provided. No information was found on the
physical properties of this compound.
Butyl benzyl phthalate is used as a plasticizer for PVC. Two
special applications differentiate it from other phthalate
esters. It is approved by the U.S. FDA for food contact in
wrappers and containers; and it is the industry standard for
plasticization of vinyl flooring because it provides stain
resistance.
No ambient water quality criterion is proposed for butyl benzyl
phthalate.
Butyl benzyl phthalate removal in a POTW by biological treatment
is expected to occur to a moderate degree.
Di-n-butyl Phthalate (68). In addition to the general remarks
and discussion on phthalate esters, specific information on di-
n-butyl phthalate (DBF) is provided. DBF is a colorless, oil
liquid, boiling at 340°C. Its water solubility at room tempera-
ture is reported to be 0.4 g/1 and 4.5 g/1 in two different chem-
istry handbooks. The formula for DBF, 05114(00004119)2
is the same as for its isomer, di-isobutyl phthalate. DBF
production is 1 to 2 percent of total U.S. phthalate ester
production.
Dibutyl phthalate is used to a limited extent as a plasticizer
for polyvinyl chloride (PVC). It is not approved for contact
with food. It is used in liquid lipsticks and as a diluent for
polysulfide dental impression materials. DBF is used as a plas-
ticizer for nitrocellulose in making gun powder, and as a fuel in
solid propellants for rockets. Further uses are insecticides,
safety glass manufacture, textile lubricating agents, printing
inks, adhesives, paper coatings, and resin solvents.
For protection of human health from the toxic properties of
dibutyl phthalate ingested through water and through contami-
nated aquatic organisms, the ambient water quality criterion is
determined to be 34 mg/1. If contaminated aquatic organisms
alone are consumed, excluding the consumption of water, the
ambient water criterion is 154 mg/1.
Although the behavior of di-n-butyl phthalate in a POTW has not
been studied, biochemical oxidation of this toxic pollutant has
been studied on a laboratory scale at concentrations higher than
would normally be expected in municipal wastewaters. Biochemical
oxidation of 35, 43, and 45 percent of theoretical oxidation were
obtained after 5, 10, and 20 days, respectively, using sewage
microorganisms as an unacclimated seed culture.
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Biological treatment in a POTW is expected to remove di-n-butyl
phthalate to a moderate degree.
Di-n-octyl Phthalate (69). In addition to the general remarks
and discussion on phthalate esters, specific information on
di-n-octyl phthalate is provided. Di-n-octyl phthalate is not to
be confused with the isomeric bis(2-ethylhexyl) phthalate which
is commonly referred to in the plastics industry as DOP. Di-n-
octyl phthalate is a liquid which boils at 220°C at 5 mm Hg. It
is insoluble in water. Its molecular formula is CgH^-
(COOCgH^y^' Its production constitutes about 1 percent of
all phthalate ester production in the U.S.
Industrially, di-n-octyl phthalate is used to plasticize poly-
vinyl chloride (PVC) resins.
No ambient water quality criterion is proposed for di-n-octyl
phthalate.
Biological treatment in a POTW is expected to lead to little or
no removal of di-n-octyl phthalate.
Diethyl Phthalate (70). In addition to the general remarks and
discussion on phthalate esters, specific information on diethyl
phthalate is provided. Diethyl phthalate, or DEP, is a colorless
liquid boiling at 296°C, and is insoluble in water. Its molecu-
lar formula is 051*4(00002*15) 2- Production of diethyl
phthalate constitutes about 1.5 percent of phthalate ester
production in the U.S.
Diethyl phthalate is approved for use in plastic food containers
by the U.S. FDA. In addition to its use as a polyvinyl chloride
(PVC) plasticizer, DEP is used to plasticize cellulose nitrate
for gun powder, to dilute polysulfide dental impression materi-
als, and as an accelerator for dyeing triacetate fibers. An
additional use which would contribute to its wide distribution in
the environment is as an approved special denaturant for ethyl
alcohol. The alcohol-containing products for which DEP is an
approved denaturant include a wide range of personal care items
such as bath preparations, bay rum, colognes, hair preparations,
face and hand creams, perfumes and toilet soaps. Additionally,
this denaturant is approved for use in biocides, cleaning solu-
tions, disinfectants, insecticides, fungicides, and room deoder-
ants which have ethyl alcohol as part of the formulation. It is
expected, therefore, that people and buildings would have some
surface loading of this toxic pollutant which would find its way
into raw wastewateis.
For the protection of human health from the toxic properties of
diethyl phthalate ingested through water and through contaminated
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aquatic organisms, the ambient water quality criterion is deter-
mined to be 350 mg/1. If contaminated aquatic organisms alone
are consumed, excluding the consumption of water, the ambient
water criterion is 1,800 mg/1.
Although the behavior of diethyl phthalate in a POTW has not been
studied, biochemical oxidation of this toxic pollutant has been
studied on a laboratory scale at concentrations higher than would
normally be expected in municipal wastewaters. Biochemical oxi-
dation of 79, 84, and 89 percent of theoretical was observed
after 5, 15, and 20 days, respectively. Biological treatment in
a POTW is expected to lead to a moderate degree of removal of
diethyl phthalate.
Dimethyl Phthalate (71). In addition to the general remarks and
discussion on phthalate esters, specific information on dimethyl
phthalate (DMP) is provided. DMP has the lowest molecular weight
of the phthalate esters - M.W. = 194 compared to M.W. of 391 for
bis(2-ethylhexyl) phthalate. DMP has a boiling point of 282°C.
It is a colorless liquid, soluble in water to the extent of 5
mg/1. Its molecular formula is CgH^COOC^) £ •
Dimethyl phthalate production in the U.S. is just under 1 percent
of total phthalate ester production. DMP is used to some extent
as a plasticizer in cellulosics; however, its principal specific
use is for dispersion of polyvinylidene fluoride (PVDF). PVDF is
resistant to most chemicals and finds use as electrical insula-
tion, chemical process equipment (particularly pipe), and as a
case for long-life finishes for exterior metal siding. Coil
coating techniques are used to apply PVDF dispersions to aluminum
or galvanized steel siding.
For the protection of human health from the toxic properties of
dimethyl phthalate ingested through water and through contami-
nated aquatic organisms, the ambient water criterion is deter-
mined to be 313 mg/1. If contaminated aquatic organisms alone
are consumed, excluding the consumption of water, the ambient
water criterion is 2,900 mg/1.
Based on limited data and observations relating molecular struc-
ture to ease of biochemical degradation of other toxic organic
pollutants, it is expected that dimethyl phthalate will be bio-
chemically oxidized to a lesser extent than domestic sewage by
biological treatment in a POTW.
Polynuclear Aromatic Hydrocarbons (72-84). The polynuclear aro-
matic hydrocarbons (PAH) selected as toxic pollutants are a group
of 13 compounds consisting of substituted and unsubstituted poly-
cyclic aromatic rings. The general class of PAH includes hetero-
cyclics, but none of those were selected as toxic pollutants.
PAH are formed as the result of incomplete combustion when
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organic compounds are burned with insufficient oxygen. PAH are
found in coke oven emissions, vehicular emissions, and volatile
products of oil and gas burning. The compounds chosen as toxic
pollutants are listed with their structural formula and melting
point (m.p.). All are relatively insoluble in water.
72 Benzo(a)anthracene (1,2-benzanthracene)
73 Benzo(a)pyrene (3,4-benzopyrene)
74 3,4-Benzofluoranthene
m.p. 162°C
m.p. 176 C
m.p. 168°C
75 Benzo(k)fluoranthene (11,12-benzofluoranthene)
76 Chrysene (1,2-benzphenanthrene)
77 Acenaphthylene
m.p. 217UC
m.p. 255°C
m.p. 92°C
78 Anthracene
m.p. 216°C
79 Benzo(ghi)perylene (1,12-benzoperylene)
m.p. not reported
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80 Fluorene (alpha-diphenylenemethane)
81 Fhenanthrene
m.p. 116°C
m.p. 101°C
82
Dibenzo(a,h)anthracene (1,2,5,6-
dibenzoanthracene)
m.p. 269°C
83
Indeno (1,2,3-cd)pyrene
(2,3-o-phenylenepyrene)
84 Pyrene
m.p. not available
m.p. 156°C
Some of these toxic pollutants have commercial or industrial
uses. Benzo(a)anthracene, benzo(a)pyrene, chrysene, anthracene,
dibenzo(a,h)anthracene, and pyrene are all used as antioxidants.
Chrysene, acenaphthylene, anthracene, fluorene, phenanthrene, and
pyrene are all used for synthesis of dyestuffs or other organic
chemicals. 3,4-Benzofluoranthrene, benzo(k)fluoranthene, benzo-
(ghi)perylene, and indeno (1,2,3-cd)pyrene have no known indus-
trial uses, according to the results of a recent literature
search.
Several of the PAH toxic pollutants are found in smoked meats, in
smoke flavoring mixtures, in vegetable oils, and in coffee. Con-
sequently, they are also found in many drinking water supplies.
The wide distribution of these pollutants in complex mixtures
with the many other PAHs which have not been designated as toxic
pollutants results in exposures by humans that cannot be associ-
ated with specific individual compounds.
The screening and verification analysis procedures used for the
toxic organic pollutants are based on gas chromatography (GC).
Three pairs of the PAH have identical elution times on the column
specified in the protocol, which means that the parameters of the
pair are not differentiated. For these three pairs [anthracene
(78) - phenanthrene (81); 3,4-benzofluoranthene (74) - benzo(k)-
fluoranthene (75); and benzo(a)anthracene (72) - chrysene (76)]
results are obtained and reported as "either-or." Either both
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are present in the combined concentration reported, or one is
present in the concentration reported.
There are no studies to document the possible carcinogenic risks
to humans by direct ingestion. Air pollution studies indicate an
excess of lung cancer mortality among workers exposed to large
amounts of PAH containing materials such as coal gas, tars, and
coke-oven emissions. However, no definite proof exists that the
PAH present in these materials are responsible for the cancers
observed.
Animal studies have demonstrated the toxicity of PAH by oral and
dermal administration. The carcinogenicity of PAH has been
traced to formation of PAH metabolites which, in turn, lead to
tumor formation. Because the levels of PAH which induce cancer
are very low, little work has been done on other health hazards
resulting from exposure. It has been established in animal
studies that tissue damage and systemic toxicity can result from
exposure to non-carcinogenic PAH compounds.
Because there were no studies available regarding chronic oral
exposures to PAH mixtures, proposed water quality criteria were
derived using data on exposure to a single compound. Two studies
were selected, one involving benzo(a)pyrene ingestion and one
involving dibenzo(a,h)anthracene ingestion. Both are known
animal carcinogens.
For the maximum protection of human health from the potential
carcinogenic effects of expsure to polynuclear aromatic hydrocar-
bons (PAH) through ingestion of water and contaminated aquatic
organisms, the ambient water concentration is zero. Concentra-
tions of PAH estimated to result in additional risk of 1 in
100,000 were derived by the EPA and the Agency is considering
setting criteria at an interim target risk level in the range of
10~7, 10~6, or 10~5 with corresponding criteria of 0.097
ng/1, 0.97 ng/1, and 9.7 ng/1, respectively.
No standard toxicity tests have been reported for freshwater or
saltwater organisms and any of the 13 PAH discussed here.
The behavior of PAH in a POTW has received only a limited amount
of study. It is reported that up to 90 percent of PAH entering a
POTW will be retained in the sludge generated by conventional
sewage treatment processes. Some of the PAH can inhibit bac-
terial growth when they are present at concentrations as low as
0.018 mg/1. Biological treatment in activated sludge units has
been shown to reduce the concentration of phenanthrene and
anthracene to some extent; however, a study of biochemical oxi-
dation of fluorene on a laboratory scale showed no degradation
after 5, 10, and 20 days. On the basis of that study and studies
of other toxic organic pollutants, some general observations were
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made relating molecular structure to ease of degradation. Those
observations lead to the conclusion that the 13 PAH selected to
represent that group as toxic pollutants will be removed only
slightly or not at all by biological treatment methods in a POTW.
Based on their water insolubility and tendency to attach to sedi
ment particles very little pass through of PAH to POTW effluent
is expected. Sludge contamination is the likely environmental
fate, although no data are available at this time to support any
conclusions about contamination of land by PAH on which sewage
sludge containing PAH is spread.
Tetrachloroethylene (85). Tetrachloroethylene
also called perchloroethylene and PCE, is a colorless, nonflam-
mable liquid produced mainly by two methods - chlorination and
pyrolysis of ethane and propane, and oxychlorination of dichloro-
ethane. U.S. annual production exceeds 300,000 tons. PCE boils
at 1 21 °C and has a vapor pressure of 1 9 mm Hg at 20°C. It is
insoluble in water but soluble in organic solvents.
Approximately two-thirds of the U.S. production of PCE is used
for dry cleaning. Textile processing and metal degreasing, in
equal amounts consume about one-quarter of the U.S. production.
The principal toxic effect of PCE on humans is central nervous
system depression when the compound is inhaled. Headache,
fatigue, sleepiness, dizziness, and sensations of intoxication
are reported. Severity of effects increases with vapor concen-
tration. High integrated exposure (concentration times duration)
produces kidney and liver damage. Very limited data on PCE
ingested by laboratory animals indicate liver damage occurs when
PCE is administered by that route. PCE tends to distribute to
fat in mammalian bodies.
One report found in the literature suggests, but does not con-
clude, that PCE is teratogenic. PCE has been demonstrated to be
a liver carcinogen in B6C3-F1 mice.
For the maximum protection of human health from the potential
carcinogenic effects of exposure to tetrachlorethylene through
ingestion of water and contaminated aquatic organisms, the ambi-
ent water concentration is zero. Concentrations of tetrachloro-
ethylene estimated to result in additional lifetime cancer risk
levels of 10~7, 10~6, and 1 0~5 are 0.02 ug/1, 0.2 ug/1, and
2 ug/1, respectively.
No data were found regarding the behavior of PCE in a POTW. Many
of the coxie organic pollutants have been investigated, at least
in laboratory scale studies, at concentrations higher than those
expected to be contained by most municipal wastewaters. General
observations have been developed relating molecular structure to
ease of degradation for all of the toxic organic pollutants. The
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conclusion reached by the study of the limited data is that
biological treatment produces a moderate removal of PCE in a POTW
by degradation. No information was found to indicate that PCE
accumulates in the sludge, but some PCE is expected to be
adsorbed onto settling particles. Some PCE is expected to be
volatilized in aerobic treatment processes and little, if any, is
expected to pass through into the effluent from the POTW.
Toluene (86). Toluene is a clear, colorless liquid with a
benzene-like odor. It is a naturally occurring compound derived
primarily from petroleum or petrochemical processes. Some
toluene is obtained from the manufacture of metallurgical coke.
Toluene is also referred to as totuol, methylbenzene, methacide,
and phenylmethane. It is an aromatic hydrocarbon with the
formula C^H^CHg. It boils at 111°C and has a vapor pres-
sure of 30 mm Hg at room temperature. The water solubility of
toluene is 535 mg/1, and it is miscible with a variety of organic
solvents. Annual production of toluene in the U.S. is greater
than two million metric tons. Approximately two-thirds of the
toluene is converted to benzene and the remaining 30 percent is
divided approximately equally into chemical manufacture, and use
as a paint solvent and aviation gasoline additive. An estimated
5,000 metric tons is discharged to the environment anually as a
constituent in wastewater.
Most data on the effects of toluene in human and other mammals
have been based on inhalation exposure or dermal contact studies.
There appear to be no reports of oral administration of toluene
to human subjects. A long term toxicity study on female rats
revealed no adverse effects on growth, mortality, appearance and
behavior, organ to body weight ratios, blood-urea nitrogen
levels, bone marrow counts, peripheral blood counts, or morphol-
ogy of maj or organs. The effects of inhaled toluene on the cen-
tral nervous system, both at high and low concentrations, have
been studied in humans and animals. However, ingested toluene is
expected to be handled differently by the body because it is
absorbed more slowly and must first pass through the liver before
reaching the nervous system. Toluene is extensively and rapidly
metabolized in the liver. One of the principal metabolic prod-
ucts of toluene is benzoic acid, which itself seems to have
little potential to produce tissue injury.
Toluene does not appear to be teratogenic in laboratory animals
or man. Nor is there any conclusive evidence that toluene is
mutagenic. Toluene has not been demonstrated to be positive in
any in vitro mutagenicity or carcinogenicity bioassay system, nor
to be~carcinogenic in animals or man.
Toluene has been found in fish caught in harbor waters in the
vicinity of petroleum and petrochemical plants. Bioconcentration
studies have not been conducted, but bioconcentration factors
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have been calculated on the basis of the octanol-water partition
coefficient.
For the protection of human health from the toxic properties of
toluene ingested through water and through contaminated aquatic
organisms, the ambient water criterion is determined to be 14.3
mg/1. If contaminated aquatic organisms alone are consumed
excluding the consumption of water, the ambient water criterion
is 424 mg/1. Available data show that the adverse effects on
aquatic life occur at concentrations as low as 5 mg/1.
Acute toxicity tests have been conducted with toluene and a
variety of freshwater fish and Daphnia magna. The latter appears
to be significantly more resistant than fish. No test results
have been reported for the chronic effects of toluene on
freshwater fish or invertebrate species.
No detailed study of toluene behavior in a POTW is available.
However, the biochemical oxidation of many of the toxic pollu-
tants has been investigated in laboratory scale studies at
concentrations greater than those expected to be contained by
most municipal wastewaters. At toluene concentrations ranging
from 3 to 250 mg/1 biochemical oxidation proceeded to 50 percent
of theoretical or greater. The time period varied from a few
hours to 20 days depending on whether or not the seed culture was
acclimated. Phenol adapted acclimated seed cultures gave the
most rapid and extensive biochemical oxidation.
Based on study of the limited data, it is expected that toluene
will be biochemically oxidized to a lesser extent than domestic
sewage by biological treatment in a POTW. The volatility and
relatively low water solubility of toluene lead to the expecta-
tion that aeration processes will remove significant quantities
of toluene from the POTW. The EPA studied toluene removal in
seven POTW facilities. The removals ranged from 40 to 100
percent. Sludge concentrations of toluene ranged from 54 x
10~3 to 1.85 mg/1.
Trichloroethylene (87). Trichloroethylene (1,1,2-trichloroethyl-
ene or TCE) is a clear, colorless liquid boiling at 87°C. It has
a vapor pressure of 77 mm Hg at room temperature and is slightly
soluble in water (1 gm/1). U.S. production is greater than 0.25
million metric tons annually. It is produced from tetrachloro-
ethane by treatment with lime in the presence of water.
TCE (CHCl=CCl2) is used for vapor phase degreasing of metal
parts, cleaning and drying electronic components, as a solvent
for paints, as a refrigerant, for extraction of oils, fats, and
waxes, and for dry cleaning. Its widespread use and relatively
high volatility result in detectable levels in many parts of
the environment.
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Data on the effects produced by ingested TCE are limited. Most
studies have been directed at inhalation exposure. Nervous sys-
tem disorders and liver damage are frequent results of inhalation
exposure. In the short term exposures, TCE acts as a central
nervous system depressant - it was used as an anaesthetic before
its other long term effects were defined.
TCE has been shown to induce transformation in a highly sensitive
in vitro Fischer rat embryo cell system (F1706) that is used for
identifying carcinogens. Severe and persistent toxicity to the
liver was recently demonstrated when TCE was shown to produce
carcinoma of the liver in mouse strain B6C3F1. One systematic
study of TCE exposure and the incidence of human cancer was based
on 518 men exposed to TCE. The authors of that study concluded
that although the cancer risk to man cannot be ruled out, expo-
sure to low levels of TCE probably does not present a very
serious and general cancer hazard.
TCE is bioconcentrated in aquatic species, making the consumption
of such species by humans a significant source of TCE. For the
protection of human health from the potential carcinogenic
effects of exposure to trichloroethylene through ingestion of
water and contaminated aquatic organisms, the ambient water con-
centration is zero. Concentrations of trichloroethylene esti-
mated to result in additional lifetime cancer risks of 10~7,
10~6, and 10~5 are 0.27 ug/1, 2.7 ug/1, and 27 ug/1, respec-
tively. If contaminated aquatic organisms alone are consumed,
excluding the consumption of water, the water concentration
should be less than 0.807 mg/1 to keep the additional lifetime
cancer risk below 10"^.
Only a very limited amount of data on the effects of TCE on
freshwater aquatic life are available. One species of fish (fat-
head minnows) showed a loss of equilibrium at concentrations
below those resulting in lethal effects.
The behavior of trichloroethylene in a POTW has not been studied.
However, in laboratory scale studies of toxic organic pollutants,
TCE was subjected to biochemical oxidation conditions. After 5,
10, and 20 days no biochemical oxidation occurred. On the basis
of this study and general observations relating molecular struc-
ture to ease of degradation, the conclusion is reached that TCE
would undergo no removal by biological treatment in a POTW. The
volatility and relatively low water solubility of TCE is expected
to result in volatilization of some of the TCE in aeration steps
in a POTW.
Vinyl Chloride (88). No freshwater organisms have been tested
with vinyl chloride and no statement can be made concerning acute
or chronic toxicity.
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For the maximum protection of human health from the potential
carcinogenic effects due to exposure of vinyl chloride through
ingestion of contaminated water and contaminated aquatic organ-
isms, the ambient water concentrations should be zero based on
the non-threshold assumption for this chemical. However, zero
level may not be attainable at the present time. Therefore, the
levels which may result in incremental increase of cancer risk
over the lifetime are estimated at 10^^, 10"^, and 10"?.
The corresponding recommended criteria are 0.020 mg/1, 0.0020
mg/1, and 0.00030 mg/1, respectively. For consumption of aquatic
organisms only, excluding consumption of water, the levels are
5.246 mg/1, 0.525 mg/1, and 0.052 mg/1, respectively.
Vinyl chloride has been used for over 40 years in producing poly-
vinyl chloride (PVC) which in turn is the most widely used mate-
rial in the manufacture of plastics throughout the world. Of the
estimated 18 billion pounds of vinyl chloride produced worldwide
in 1972, about 25 percent was manufactured in the United States.
Production of vinyl chloride in the United States reached
slightly over 5 billion pounds in 1978.
Vinyl chloride and polyvinyl chloride are used in the manufacture
of numerous products in building and construction, the automotive
industry, for electrical wire insulation and cables, piping,
industrial and household equipment, packaging for food products,
medical supplies, and is depended upon heavily by the rubber,
paper, and glass industries. Polyvinyl chloride and vinyl chlo-
ride copolymers are distributed and processed in a variety of
forms including dry resins, plastisol (dispersions in plasti-
cizers), organosol, (dispersions in plasticizers plus volatile
solvent), and latex (colloidal dispersion in water). Latexes are
used to coat or impregnate paper, fabric, or leather.
Vinyl chloride (Cl^CHCl; molecular weight 62.5) is a highly
flammable chloroolefinic hydrocarbon which emits a sweet or
pleasant odor and has a vapor density slightly more than twice
that of air. It has a boiling point of -13.9°C and a melting
point of -153.8°C. Its solubility in water at 28°C is 0.11 g/
100 g water and it is soluble in alcohol and very soluble in
ether and carbon tetrachloride. Vinyl chloride is volatile and
readily passes from solution into the gas phase under most
laboratory and ecological conditions. Many salts such as soluble
silver and copper salts, ferrous chloride, platinous chloride,
iridium dichloride, and mercurous chloride to name a few, have
the ability to form complexes with vinyl chloride which results
in its increased solubility in water. Conversely, alkali metal
salts such as sodium or potassium chloride may decrease the
solubility of vinyl chloride in ionic strengths of the aqueous
solution. Therefore, the amounts of vinyl chloride in water
could be influenced significantly by the presence of salts.
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Vinyl chloride introduced into aquatic systems will most probably
be quickly transferred to the atmosphere through volatilization.
In fact, results from model simulations indicate that vinyl chlo-
ride should not remain in an aquatic ecosystem under most natural
conditions.
Based on the information found, it does not appear that oxidation
hydrolysis, biodegradation or sorption, are important fate pro-
cesses for vinyl chloride in the aquatic environment.
Based on the 1982 POTW study, "Fate of Priority Pollutants in
Publicly Owned Treatment Works, Final Report," Effluent Guide-
lines Division, U.S. Environmental Protection Agency, EPA
440/1-82/303, September 1983, the removal efficiency for vinyl
chloride at a POTW with secondary treatment is 94 percent.
4,4'-DDD (94). 4,4'-ODD is toxic by ingestion, inhalation, skin
absorption, and is combustible.
a-£ndosulfan-alpha (95). Endosulfan is toxic by ingestion,
inhalation and skin absorption.
a-BHC-alpha (102). BHC-alpha is toxic by ingestion, skin
absorption, is an eye irritant, and a central nervous system
depressant.
b-BHC-beta (103). BHC-beta is moderately toxic by inhalation,
highly toxic by ingestion, and is a strong irritant by skin
absorption. It acts as a central nervous system depressant.
Polychlorinated Biphenyls (106 - 112). Polychlorinated biphenyls
(C12H1 OnC;Ln'H10~nC^n where n can range from 1 to 10),
designated PCB's, are chlorinated derivatives of biphenyls. The
commercial products are complex mixtures of chlorobiphenyls, but
are no longer produced in the U.S. The mixtures produced for-
merly were characterized by the percentage chlorination. Direct
chlorination of biphenyl was used to produce mixtures containing
from 21 to 70 percent chlorine. Seven of these mixtures have
been selected as toxic pollutants:
Toxic
Pollu- Range (°C)
tant Percent Distilla- Pour Water
No. Name Chlorine tion Point (°C) Solubility
Arochlor
106 1242 42 325-366 -19 240
107 1254 54 365 390 10 12
108 1221 20.5-21.5 275-320 1 <200
109 1232 31.4-32.5 290-325 -35.5
110 1248 48 340-375 - 7 54
111 1260 60 385-420 31 2.7
112 1016 41 323-356 — 225-250
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The arochlors 1221, 1232, 1016, 1242, and 1248 are colorless,
oily liquids; 1254 is a viscous liquid; 1260 is a sticky resin at
room temperature. Total annual U.S. production of PCB's averaged
about 20,000 tons in 1972 to 1974.
Prior to 1971, PCB's were used in several applications including
plasticizers, heat transfer liquids, hydraulic fluids, lubri-
cants, vacuum pump and compressor fluids, and capacitor and
transformer oils. After 1970, when PCB use was restricted to
closed systems, the latter two uses were the only commercial
applications.
The toxic effects of PCB's ingested by humans have been reported
to range from acne-like skin eruptions and pigmentation of the
skin to numbness of limbs, hearing and vision problems, and
spasms. Interpretation of results is complicated by the fact
that the very highly toxic polychlorinated dibenzofurans (PCDF's)
are found in many commercial PCB mixtures. Photochemical and
thermal decomposition appear to accelerate the transformation of
PCB's to PCDF's. Thus the specific effects of PCB's may be
masked by the effects of PCDF's. However, if PCDF's are fre-
quently present to some extent in any PCB mixture, then their
effects may be properly included in the effects of PCB mixtures.
Studies of effects of PCB's in laboratory animals indicate that
liver and kidney damage, large weight losses, eye discharges, and
interference with some metabolic processes occur frequently.
Teratogenic effects of PCB's in laboratory animals have been
observed, but are rare. Growth retardations during gestation,
and reproductive failure are more common effects observed in
studies of PCB teratogenicity. Carcinogenic effects of PCB's
have been studied in laboratory animals with results interpreted
as positive. Specific reference has been made to liver cancer in
rats in the discussion of water quality criterion formulation.
For the maximum protection of human health from the potential
carcinogenic effects of exposure to PCB's through ingestion of
water and contaminated aquatic organisms, the ambient water con-
centration should be zero. Concentrations of PCB's estimated to
result in additional lifetime cancer risk at risk levels of
10-7, 10~6, and 10~5 are 0.0026 ng/1, 0.026 ng/1, and 0.26
ng/1, respectively.
The behavior of PCB's in a POTW has received limited study. Most
PCB's will be removed with sludge. One study showed removals of
82 to 89 percent, depending on suspended solid removal. The
PCB's adsorb onto suspended sediments and other particulates. In
laboratory scale experiments with PCB 1221, 81 percent was
removed by degradation in an activated sludge system in 47 hours.
Biodegradation can form polychlorinated dibenzofurans which are
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more toxic than PCB's (as noted earlier). PCB's at concentra-
tions of 0.1 to 1,000 mg/1 inhibit or enhance bacterial growth
rates, depending on the bacterial culture and the percentage
chlorine in the PCB. Thus, activated sludge may be inhibited by
PCB's. Based on studies of bioaccumulation of PCB's in food
crops grown on soils amended with PCB-containing sludge, the U.S.
FDA. has recommended a limit of 10 mg PCB/kg dry weight of sludge
used for application to soils bearing food crops.
Antimony (114). Antimony, classified as a non-metal or
metalloid,is a silvery white, brittle crystalline solid.
Antimony is found in small ore bodies throughout the world.
Principal ores are oxides of mixed antimony valences, and an
oxysulfide ore. Complex ores with metals are important because
the antimony is recovered as a by-product. Antimony melts at
631°C, and is a poor conductor of electricity and heat.
Annual U.S. consumption of primary antimony ranges from 10,000 to
20,000 tons. About half is consumed in metal products - mostly
antimonial lead for lead acid storage batteries, and about half
in non-metal products. A principal compound is antimony trioxide
which is used as a flame retardant in fabrics, and as an opaci-
fier in glass, ceramics, and enamels. Several antimony compounds
are used as catalysts in organic chemicals synthesis, as fluori-
nating agents (the antimony fluoride), as pigments, and in fire-
works. Semiconductor applications are economically significant.
Essentially no information on antimony-induced human health
effects has been derived from community epidemiology studies.
The available data are in literature relating effects observed
with therapeutic or medicinal uses of antimony compounds and
industrial exposure studies. Large therapeutic doses of anti-
monial compounds, usually used to treat schistisomiasis, have
caused severe nausea, vomiting, convulsions, irregular heart
action, liver damage, and skin rashes. Studies of acute
industrial antimony poisoning have revealed loss of appetite,
diarrhea, headache, and dizziness in addition to the symptoms
found in studies of therapeutic doses of antimony.
For the protection of human health from the toxic properties of
antimony ingested through water and through contaminated aquatic
organisms the ambient water criterion is determined to be 0.146
mg/1. If contaminated aquatic organisms are consumed, excluding
the consumption of water, the ambient water criterion is deter-
mined to be 45 mg/1. Available data show that adverse effects on
aquatic life occur at concentrations higher than those cited for
human health risks.
Very little information is available regarding the behavior of
antimony in a POTW. The limited solubility of most antimony
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compounds expected in a POTW, i.e., the oxides and sulfides, sug-
gests that at least part of the antimony entering a POTW will be
precipitated and incorporated into the sludge. However, some
antimony is expected to remain dissolved and pass through the
POTW into the effluent. Antimony compounds remaining in the
sludge under anaerobic conditions may be connected to stibine
(SbH3), a very soluble and very toxic compound. There are no
data to show antimony inhibits any POTW processes. Antimony is
not known to be essential to the growth of plants, and has been
reported to be moderately toxic. Therefore, sludge containing
large amounts of antimony could be detrimental to plants if it is
applied in large amounts to cropland.
Arsenic (115). Arsenic is classified as a non-metal or
metalloid. Elemental arsenic normally exists in the alpha-
crystalline metallic form which is steel gray and brittle, and in
the beta form which is dark gray and amorphous. Arsenic sublimes
at 615°C. Arsenic is widely distributed throughout the world in
a large number of minerals. The most important commercial source
of arsenic is as a by-product from treatment of copper, lead,
cobalt, and gold ores. Arsenic is usually marketed as the
trioxide (As203>. Annual U.S. production of the trioxide
approaches 40,000 tons.
The principal use of arsenic is in agricultural chemicals (herbi-
cides) for controlling weeds in cotton fields. Arsenicals have
various applications in medicinal and vetrinary use, as wood
preservatives, and in semiconductors.
The effects of arsenic in humans were known by the ancient Greeks
and Romans. The principal toxic effects are gastrointestinal
disturbances. Breakdown of red blood cells occurs. Symptoms of
acute poisoning include vomiting, diarrhea, abdominal pain,
lassitude, dizziness, and headache. Longer exposure produced
dry, falling hair, brittle, loose nails, eczema, and exfoliation.
Arsenicals also exhibit teratogenic and mutagenic effects in
humans. Oral administration of arsenic compounds has been
associated clinically with skin cancer for nearly one hundred
years. Since 1888 numerous studies have linked occupational
exposure and therapeutic administration of arsenic compounds to
increased incidence of respiratory and skin cancer.
For the maximum protection of human health from the potential
carcinogenic effects of exposure to arsenic through ingestion of
water and contaminated aquatic organisms, the ambient water con-
centration is zero. Concentrations of arsenic estimated to
result in additional lifetime cancer risk levels of 10"?,
10~6, and 10-5 are 2.2 x 10;7 mg/1, 2. 2 x 10~6 mg/1, and
2.2 x 10"^ m8/l> respectively. If contaminated aquatic organ-
isms alone are consumed, excluding the consumption of water, the
water concentration should be less than 1.75 x 10"^ to keep the
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increased lifetime cancer risk below 10"^. Available data show
that adverse effects on aquatic life occur at concentrations
higher than those cited for human health risks.
A few studies have been made regarding the behavior of arsenic in
a POTW. One EPA survey of nine POTW facilities reported influent
concentrations ranging from 0.0005 to 0.693 mg/1; effluents from
three POTW facilities having biological treatment contained
0.0004 to 0.01 mg/1; two POTW facilities showed arsenic removal
efficiencies of 50 and 71 percent in biological treatment. Inhi-
bition of treatment processes by sodium arsenate is reported to
occur at 0.1 mg/1 in activated sludge, and 1.6 mg/1 in anaerobic
digestion processes. In another study based on data from 60 POTW
facilities, arsenic in sludge ranged from 1.6 to 65.6 mg/kg and
the median value was 7.8 mg/kg. Arsenic in sludge spread on
cropland may be taken up by plants grown on that land. Edible
plants can take up arsenic, but normally their growth is
inhibited before the plants are ready for harvest.
Asbestos (116). Asbestos is a generic term used to describe a
group of hydrated mineral silicates that can appear in a fibrous
crystal form (asbestiform) and, when crushed, can separate into
flexible fibers. The types of asbestos presently used commer-
cially fall into two mineral groups: the serpentine and amphib-
ole groups. Asbestos is mineralogically stable and is not prone
to significant chemical or biological degradation in the aquatic
environment. In 1978, the total consumption of asbestos in the
U.S. was 583,000 metric tons. Asbestos is an excellent insulat-
ing material and is used in a wide variety of products. Based on
1975 figures, the total annual identifiable asbestos emissions
are estimated at 243,527 metric tons. Land discharges account
for 98.3 percent of the emissions, air discharges account for 1.5
percent, and water discharges account for 0.2 percent.
Asbestos has been found to produce significant incidence of dis-
ease among workers occupationally exposed in mining and milling,
in manufacturing., and in the use of materials containing the
fiber. The predominant type of exposure has been inhalation,
although some asbestos may be swallowed directly or ingested
after being expectorated from the respiratory tract. Non-
cancerous asbestos disease has been found among people directly
exposed to high levels of asbestos as a result of excessive work
exposure; much less frequently, among those with lesser exposures
although there is extensive evidence of pulmonary disease among
people exposed to airborne asbestos. There is little evidence of
disease among people exposed to waterborne fibers.
Asbestos at the concentrations currently found in the aquatic
environment does not appear to exert toxic effects on aquatic
organisms. For the maximum protection of human health from the
potential carcinogenic effects of exposure to asbestos through
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ingestion of water and contaminated aquatic organisms, the ambi-
ent water concentration should be zero based on the non-threshold
assumption of this substance. However, zero level may not be
attainable at the present time. Therefore, levels which may
result in incremental increase of cancer risk over the life time
are estimated at 10~5, 10""°, and 10"'. The corresponding
recommended criteria are 300,000 fibers/1, 30,000 fibers/1, and
3,000 fibers/1.
The available data indicate that technologies used at POTW for
reducing levels of total suspended solids in wastewater also
provide a concomitant reduction in asbestos levels. Asbestos
removal efficiencies ranging from 80 percent to greater than 99
percent have been reported following sedimentation of wastewater.
Filtration and sedimentation with chemical addition (i.e., lime
and/or polymer) have achieved even greater percentage removals.
Beryllium (117). Beryllium is a dark gray metal of the alkaline
earth family. It is relatively rare, but because of its unique
properties finds widespread use as an alloying element, espe-
cially for hardening copper which is used in springs, electrical
contacts, and non-sparking tools. World production is reported
to be in the range of 250 tons annually. However, much more
reaches the environment as emissions from coal burning opera-
tions. Analysis of coal indicates an average beryllium content
of 3 ppm and 0.1 to 1.0 percent in coal ash or fly ash.
The principal ores are beryl (SBeO.A^CK. 6SiC>2) and
bertrandite [86481207(0^2]. Only two industrial
facilities produce beryllium in the U.S. because of limited
demand and the highly toxic character. About two-thirds of the
annual production goes into alloys, 20 percent into heat sinks,
and 10 percent into beryllium oxide (BeO) ceramic products.
Beryllium has a specific gravity of 1.846, making it the lightest
metal with a high melting point (1,350°C). Beryllium alloys are
corrosion resistant, but the metal corrodes in aqueous environ-
ments. Most common beryllium compounds are soluble in water, at
least to the extent necessary to produce a toxic concentration of
beryllium ions.
Most data on toxicity of beryllium is for inhalation of beryllium
oxide dust. Some studies on orally administered beryllium in
laboratory animals have been reported. Despite the large number
of studies implicating beryllium as a carcinogen, there is no
recorded instance of cancer being produced by ingestion. How-
ever, a recently convened panel of uninvolved experts concluded
that epidemiologic evidence is suggestive that beryllium is a
carcinogen in man.
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In the aquatic environment beryllium is chronically toxic to
aquatic organisms at 0.0053 mg/1. Water softness has a large
effect on beryllium toxicity to fish. In soft water, beryllium
is reportedly 100 times as toxic as in hard water.
For the maximum protection of human health from the potential
carcinogenic effects of exposure to beryllium through ingestion
of water and contaminated aquatic organisms the ambient water
concentration is zero. Concentrations of beryllium estimated to
result in additional lifetime cancer risk levels of 10"',
10-o, ancj iQ-5 are 0.68 ng/1, 6.8 ng/1, and 68 ng/1, respec-
tively. If contaminated aquatic organisms alone are consumed
excluding the consumption of water, the concentration should be
less than 0.00117 mg/1 to keep the increased lifetime cancer risk
below 10~5.
Information on the behavior of beryllium in a POTW is scarce.
Because beryllium hydroxide is insoluble in water, most beryllium
entering a POTW will probably be in the form of suspended solids.
As a result most of the beryllium will settle and be removed with
sludge. However, beryllium has been shown to inhibit several
enzyme systems, to interfere with DNA metabolism in liver, and to
induce chromosomal and mitotic abnormalities. This interference
in cellular processes may extend to interfere with biological
treatment processes. The concentration and effects of beryllium
in sludge which could be applied to cropland have not been
studied.
Cadmium (118). Cadmium is a relatively rare metallic element
that is seldom found in sufficient quantities in a pure state to
warrant mining or extraction from the earth's surface. It is
found in trace amounts of about 1 ppm throughout the earth's
crust. Cadmium is, however, a valuable by-product of zinc pro-
duction.
Cadmium is used primarily as an electroplated metal, and is found
as an impurity in the secondary refining of zinc, lead, and
copper.
Cadmium is an extremely dangerous cumulative toxicant, causing
progressive chronic poisoning in mammals, fish, and probably
other organisms. The metal is not excreted.
Toxic effects of cadmium on man have been reported from through-
out the world. Cadmium may be a factor in the development of
such human pathological conditions as kidney disease, testicular
tumors, hypertension, arteriosclerosis, growth inhibition,
chronic disease of old age, and cancer. Cadmium is normally
ingested by humans through food and water as well as by breathing
air contaminated by cadmium dust. Cadmium is cumulative in the
liver, kidney, pancreas, and thyroid of humans and other animals.
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A severe bone and kidney syndrome known as itai-itai disease has
been documented in Japan as caused by cadmium ingestion via
drinking water and contaminated irrigation water. Ingestion of
as little as 0.6 mg/day has produced the disease. Cadmium acts
synergistically with other metals. Copper and zinc substantially
increase its toxicity.
Cadmium is concentrated by marine organisms, particularly
molluscs, which accumulate cadmium in calcareous tissues and in
the viscera. A concentration factor of 1,000 for cadmium in fish
muscle has been reported, as have concentration factors of 3,000
in marine plants and up to 29,600 in certain marine animals. The
eggs and larvae of fish are apparently more sensitive than adult
fish to poisoning by cadmium, and crustaceans appear to be more
sensitive than fish eggs and larvae.
For the protection of human health from the toxic properties of
cadmium ingested through water and through contaminated aquatic
organisms, the ambient water criterion is determined to be 0.010
mg/1. Available data show that adverse effects on aquatic life
occur at concentrations in the same range as those cited for
human health, and they are highly dependent on water hardness.
Cadmium is not destroyed when it is introduced into a POTW, and
will either pass through to the POTW effluent or be incorporated
into the POTW sludge. In addition, it can interfere with the
POTW treatment process.
In a study of 189 POTW facilities, 75 percent of the primary
plants, 57 percent of the trickling filter plants, 66 percent of
the activated sludge plants, and 62 percent of the biological
plants allowed over 90 percent of the influent cadmium to pass
through to the POTW effluent. Only two of the 189 POTW facili-
ties allowed less than 20 percent pass-through, and none less
than 10 percent pass-through. POTW effluent concentrations
ranged from 0.001 to 1.97 mg/1 (mean 0.028 mg/1, standard
deviation 0.167 mg/1).
Cadmium not passed through the POTW will be retained in the
sludge where it is likely to build up in concentration. Cadmium
contamination of sewage sludge limits its use on land since it
increases the level of cadmium in the soil. Data show that
cadmium can be incorporated into crops, including vegetables and
grains, from contaminated soils. Since the crops themselves show
no adverse effects from soils with levels up to 100 rag/kg cad-
mium, these contaminated crops could have a significant impact on
human health. Two Federal agencies have already recognized the
potential adverse human health effects posed by the use of sludge
on cropland. The FDA recommends that sludge containing over 30
mg/kg of cadmium should not be used on agricultural land. Sewage
sludge contains 3 to 300 mg/kg (dry basis) of cadmium mean = 10
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mg/kg; median = 16 mg/kg. The USDA also recommends placing
limits on the total cadmium from sludge that may be applied to
land.
Chromium (119). Chromium is an elemental metal usually found as
a chromite (FeO.C^C^). The metal is normally produced by
reducing the oxide with aluminum. A significant proportion of
the chromium used is in the form of compounds such as sodium
dichromate (Na2CrC>4), and chromic acid (CrC^) - both are
hexavalent chromium compounds.
Chromium is found as an alloying component of many steels and its
compounds are used in electroplating baths, and as corrosion
inhibitors for closed water circulation systems.
The two chromium forms most frequently found in industry waste-
waters are hexavalent and trivalent chromium. Hexavalent chro-
mium is the form used for metal treatments. Some of it is
reduced to trivalent chromium as part of the process reaction.
The raw wastewater containing both valence states is usually
treated first to reduce remaining hexavalent to trivalent chro-
mium, and second to precipitate the trivalent form as the hydrox-
ide. The hexavalent form is not removed by lime treatment.
Chromium, in its various valence states, is hazardous to man. It
can produce lung tumors when inhaled, and induces skin sensitiza-
tions. Large doses of chromates have corrosive effects on the
intestinal tract and can cause inflammation of the kidneys.
Hexavalent chromium is a known human carcinogen. Levels of chro-
mate ions that show no effect in man appear to be so low as to
prohibit determination, to date.
The toxicity of chromium salts to fish and other aquatic life
varies widely with the species, temperature, pH, valence of the
chromium, and synergistic or antagonistic effects, especially the
effect of water hardness. Studies have shown that trivalent
chromium is more toxic to fish of some types than is hexavalent
chromium. Hexavalent chromium retards growth of one fish species
at 0.0002 mg/1. Fish food organisms and other lower forms of
aquatic life are extremely sensitive to chromium. Therefore,
both hexavalent and trivalent chromium must be considered harmful
to particular fish or organisms.
For the protection of human health from the toxic properties of
chromium (except hexavalent chromium) ingested through water and
contaminated aquatic organisms, the ambient water quality crite-
rion is 170 mg/1. If contaminated aquatic organisms alone are
consumed, excluding the consumption of water, the ambient water
criterion for trivalent chromium is 3,443 mg/1. The ambient
water quality criterion for hexavalent chromium is recommended to
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be identical to the existing drinking water standard for total
chromium which is 0.050 mg/1.
Chromium is not destroyed when treated by a POTW (although the
oxidation state may change), and will either pass through to the
POTW effluent or be incorporated into the POTW sludge. Both oxi-
dation states can cause POTW treatment inhibition and can also
limit the usefulness of municipal sludge.
Influent concentrations of chromium to POTW facilities have been
observed by EPA to range from 0.005 to 14.0 mg/1, with a median
concentration of 0.1 mg/1. The efficiencies for removal of chro-
mium by the activated sludge process can vary greatly, depending
on chromium concentration in the influent, and other operating
conditions at the POTW. Chelation of chromium by organic matter
and dissolution due to the presence of carbonates can cause
deviations from the predicted behavior in treatment systems.
The systematic presence of chromium compounds will halt nitrifi-
cation in a POTW for short periods, and most of the chromium will
be retained in the sludge solids. Hexavalent chromium has been
reported to severely affect the nitrification process, but tri-
valent chromium has little or no toxicity to activated sludge,
except at high concentrations. The presence of iron, copper, and
low pH will increase the toxicity of chromium in a POTW by
releasing the chromium into solution to be ingested by micro-
organisms in the POTW.
The amount of chromium which passes through to the POTW effluent
depends on the type of treatment processes used by the POTW. In
a study of 240 POTW facilities, 56 percent of the primary plants
allowed more than 80 percent pass-through to POTW effluent. More
advanced treatment results in less pass-through. POTW effluent
concentrations ranged from 0.003 to 3.2 mg/1 total chromium (mean
= 0.197, standard deviation = 0.48), and from 0.002 to 0.1 mg/1
hexavalent chromium (mean = 0.017, standard deviation = 0.020).
Chromium not passed through the POTW will be retained in the
sludge, where it is likely to build up in concentration. Sludge
concentrations of total chromium of over 20,000 mg/kg (dry basis)
have been observed. Disposal of sludges containing very high
concentrations of trivalent chromium can potentially cause prob-
lems in uncontrolled landfills. Incineration, or similar
destructive oxidation processes, can produce hexavalent chromium
from lower valence states. Hexavalent chromium is potentially
more toxic than trivalent chromium. In cases where high rates of
chrome sludge application on land are used, distinct growth
inhibition and plant tissue uptake have been noted.
Pretreatment of discharges substantially reduces the concentra-
tion of chromium in sludge. In Buffalo, New York, pretreatment
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of electroplating waste resulted in a decrease in chromium con-
centrations in POTW sludge from 2,510 to 1,040 mg/kg. A similar
reduction occurred in Grand Rapids, Michigan, POTW facilities
where the chromium concentration in sludge decreased from 11,000
to 2,700 mg/kg when pretreatment was made a requirement.
Copper (120). Copper is a metallic element that sometimes is
found free, as the native metal, and is also found in minerals
such as cuprite (Cu20), malechite [CuC03.Cu(OH)2l, azurite
[2CuCOQ.Cu(OH)2], chalcopyrite (CuFeS2>, and bornite
(C^FeS^.). Copper is obtained from these ores by smelting,
leaching, and electrolysis. It is used in the plating, electri-
cal, plumbing, and heating equipment industries, as well as in
insecticides and fungicides.
Traces of copper are found in all forms of plant and animal life,
and the metal is an essential trace element for nutrition.
Copper is not considered to be a cumulative systemic poison for
humans as it is readily excreted by the body, but it can cause
symptoms of gastroenteritis, with nausea and intestinal irrita-
tions, as relatively low dosages. The limiting factor in domes-
tic water supplies is taste. To prevent this adverse organolep-
tic effect of copper in water, a criterion of 1 mg/1 has been
established.
The toxicity of copper to aquatic organisms varies significantly,
not only with the species, but also with the physical and chemi-
cal characteristics of the water, including temperature, hard-
ness, turbidity, and carbon dioxide content. In hard water, the
toxicity of copper salts may be reduced by the precipitation of
copper carbonate or other insoluble compounds. The sulfates of
copper and zinc, and of copper and calcium are synergistic in
their toxic effect on fish.
Relatively high concentrations of copper may be tolerated by
adult fish for short periods of time; the critical effect of
copper appears to be its higher toxicity to young or juvenile
fish. Concentrations of 0.02 to 0.03 mg/1 have proved fatal to
some common fish species. In general the salmonoids are very
sensitive and the sunfishes are less sensitive to copper.
The recommended criterion to protect freshwater aquatic life is
0.0056 mg/1 as a 24-hour average, and 0.012 mg/1 maximum concen-
tration at a hardness of 50 mg/1 CaCC^. For total recoverable
copper the criterion to protect freshwater aquatic life is 0.0056
mg/1 as a 24-hour average.
Copper salts cause undesirable color reactions in the food indus-
try and cause pitting when deposited on some other metals such as
aluminum and galvanized steel. To control undesirable taste and
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odor quality of ambient water due to the organoleptic properties
of copper, the estimated level is 1.0 mg/1 for total recoverable
copper.
Irrigation water containing more than minute quantities of copper
can be detrimental to certain crops. Copper appears in all
soils, and its concentration ranges from 10 to 80 ppm. In soils,
copper occurs in association with hydrous oxides of manganese and
iron, and also as soluble and insoluble complexes with organic
matter. Copper is essential to the life of plants, and the
normal range of concentration in plant tissue is from 5 to 20
ppm. Copper concentrations in plants normally do not build up to
high levels when toxicity occurs. For example, the concentra-
tions of copper in snapbean leaves and pods was less than 50 and
20 mg/kg, respectively, under conditions of severe copper toxic-
ity. Even under conditions of copper toxicity, most of the
excess copper accumulates in the roots; very little is moved to
the aerial part of the plant.
Copper is not destroyed when treated by a POTW, and will either
pass through to the POTW effluent or be retained in the POTW
sludge. It can interfere with the POTW treatment processes and
can limit the usefulness of municipal sludge.
The influent concentration of copper to a POTW has been observed
by the EPA to range from 0.01 to 1.97 mg/1, with a median concen-
tration of 0.12 mg/1. The copper that is removed from the
influent stream of a POTW is absorbed on the sludge or appears in
the sludge as the hydroxide of the metal. Bench scale pilot
studies have shown that from about 25 percent to 75 percent of
the copper passing through the activated sludge process remains
in solution in the final effluent. Four-hour slug dosages of
copper sulfate in concentrations exceeding 50 mg/1 were reported
to have severe effects on the removal efficiency of an unaccli-
mated system, with the system returning to normal in about 100
hours. Slug dosages of copper in the form of copper cyanide were
observed to have much more severe effects on the activated sludge
system, but the total system returned to normal in 24 hours.
In a recent study of 268 POTW facilities, the median pass-through
was over 80 percent for primary plants and 40 to 50 percent for
trickling filter, activated sludge, and biological treatment
plants. POTW effluent concentrations of copper ranged from 0.003
to 1.8 mg/1 (mean 0.126, standard deviation 0.242).
Copper which does not pass through the POTW will be retained in
the sludge where it will build up in concentration. The presence
of excessive levels of copper in sludge may limit its use on
cropland. Sewage sludge contains up to 16,000 mg/kg of copper,
with 730 mg/kg as the mean value. These concentrations are
significantly greater than those normally found in soil, which
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usually range from 18 to 80 rag/kg. Experimental data indicate
that when dried sludge is spread over tillable land, the copper
tends to remain in place down to the depth of the tillage, except
for copper which is taken up by plants grown in the soil. Recent
investigation has shown that the extractable copper content of
sludge-treated soil decreased with time, which suggests a rever-
sion of copper to less soluble forms was occurring.
Cyanide (121). Cyanides are among the most toxic of pollutants
commonly observed in industrial wastewaters. Introduction of
cyanide into industrial processes is usually by dissolution of
potassium cyanide (KCN) or sodium cyanide (NaCN) in process
waters. However, hydrogen cyanide (HCN) formed when the above
salts are dissolved in water, is probably the most acutely lethal
compound.
The relationship of pH to hydrogen cyanide formation is very
important. As pH is lowered to below 7, more than 99 percent of
the cyanide is present as HCN and less than 1 percent as cyanide
ions. Thus, at neutral pH, that of most living organisms, the
more toxic form of cyanide prevails.
Cyanide ions combine with numerous heavy metal ions to form com-
plexes. The complexes are in equilibrium with HCN. Thus, the
stability of the metal-cyanide complex and the pH determine the
concentration of HCN. Stability of the metal-cyanide anion com-
plexes is extremely variable. Those formed with zinc, copper,
and cadmium are not stable - they rapidly dissociate, with pro-
duction of HCN, in near neutral or acid waters. Some of the com-
plexes are extremely stable. Cobaltocyanide is very resistant to
acid distillation in the laboratory. Iron cyanide complexes are
also stable, but undergo photodecomposition to give HCN upon
exposure to sunlight. Synergistic effects have been demonstrated
for the metal cyanide complexes making zinc, copper, and cadmium
cyanides more toxic than an equal concentration of sodium
cyanide.
The toxic mechanism of cyanide is essentially an inhibition of
oxygen metabolism, i.e., rendering the tissues incapable of
exchanging oxygen. The cyanogen compounds are true noncumulative
protoplasmic poisons. They arrest the activity of all forms of
animal life. Cyanide shows a very specific type of toxic action.
It inhibits the cytochrome oxidase system. This system is the
one which facilitates electron transfer from reduced metabolites
to molecular oxygen. The human body can convert cyanide to a
non-toxic thiocyanate and eliminate it. However, if the quantity
of cyanide ingested is too great at one time, the inhibition of
oxygen utilization proves fatal before the detoxifying reaction
reduces the cyanide concentration to a safe level.
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Cyanides are more toxic to fish than to lower forms of aquatic
organisms such as midge larvae, crustaceans, and mussels. Toxic-
ity to fish is a function of chemical form and concentration, and
is influenced by the rate of metabolism (temperature), the level
of dissolved oxygen, and pH. In laboratory studies free cyanide
concentrations ranging from 0.05 to 0.14 mg/1 have been proven to
be fatal to sensitive fish species including trout, bluegill, and
fathead minnows. Levels above 0.2 mg/1 are rapidly fatal to most
fish species. Long term sublethal concentrations of cyanide as
low as 0.01 mg/1 have been shown to affect the ability of fish to
function normally, e.g., reproduce, grow, and swim.
For the protection of human health from the toxic properties of
cyanide ingested through water and through contaminated aquatic
organisms, the ambient water quality criterion is determined to
be 0.200 mg/1.
Persistence of cyanide in water is highly variable and depends
upon the chemical form of cyanide in the water, the concentration
of cyanide, and the nature of other constituents. Cyanide may be
destroyed by strong oxidizing agents such as permanganate and
chlorine. Chlorine is commonly used to oxidize strong cyanide
solutions. Carbon dioxide and nitrogen are the products of com-
plete oxidation. But if the reaction is not complete, the very
toxic compound, cyanogen chloride, may remain in the treatment
system and subsequently be released to the environment. Partial
chlorination may occur as part of a POTW treatment, or during the
disinfection treatment of surface water for drinking water prep-
aration.
Cyanides can interfere with treatment processes in a POTW, or
pass through to ambient waters. At low concentrations and with
acclimated microflora, cyanide may be decomposed by microorga-
nisms in anaerobic and aerobic environments or waste treatment
systems. However, data indicate that much of the cyanide intro-
duced passes through to the POTW effluent. The mean pass-through
pf 1 4 biological plants was 71 percent. In a recent study of 41
POTW facilities the effluent concentrations ranged from 0.002 to
100 mg/1 (mean = 2.518, standard deviation = 15.6). Cyanide also
enhances the toxicity of metals commonly found in POTW effluents,
including the toxic pollutants cadmium, zinc, and copper.
Data for Grand Rapids, Michigan, showed a significant decline in
cyanide concentrations downstream from the POTW after pretreat-
ment regulations were put in force. Concentrations fell from
0.66 mg/1 before, to 0.01 mg/1 after pretreatment was required.
Lead (122). Lead is a soft, malleable, ductile, blueish-gray,
metallic element, usually obtained from the mineral galena (lead
sulfide, PbS), anglesite (lead sulfate, PbSO^), or cerussite
(lead carbonate, PbC03). Because it is usually associated with
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minerals of zinc, silver, copper, gold, cadmium, antimony, and
arsenic, special purification methods are frequently used before
and after extraction of the metal from the ore concentrate by
smelting.
Lead is widely used for its corrosion resistance, sound and
vibration absorption, low melting point (solders), and relatively
high imperviousness to various forms of radiation. Small amounts
of copper, antimony and other metal's can be alloyed with lead to
achieve greater hardness, stiffness, or corrosion resistance than
is afforded by the pure metal. Lead compounds are used in glazes
and paints. About one third of U.S. lead consumption goes into
storage batteries. About half of U.S. lead consumption is from
secondary lead recovery. U.S. consumption of lead is in the
range of one million tons annually.
Lead ingested by humans produces a variety of toxic effects
including impaired reproductive ability, disturbances in blood
chemistry, neurological disorders, kidney damage, and adverse
cardiovascular effects. Exposure to lead in the diet results in
permanent increase in lead levels in the body. Most of the lead
entering the body eventually becomes localized in the bones where
it accumulates. Lead is a carcinogen or cocarcinogen in some
species of experimental animals. Lead is teratogenic in experi-
mental animals. Mutagenicity data are not available for lead.
The ambient water quality criterion for lead is recommended to be
identical to the existng drinking water standard which is 0.050
mg/1. Available data show that adverse effects on aquatic life
occur at concentrations as low as 7.5 x 10"^ mg/1 of total
recoverable lead as a 24-hour average with a water hardness of 50
mg/1 as
Lead is not destroyed in a POTW, but is passed through to the
effluent or retained in the POTW sludge; it can interfere with
POTW treatment processes and can limit the usefulness of POTW
sludge for application to agricultural croplands. Threshold con-
centration for inhibition of the activated sludge process is 0.1
mg/1, and for the nitrification process is 0.5 mg/1. In a study
of 214 POTW facilities, median pass through values were over 80
percent for primary plants and over 60 percent for trickling
filter, activated sludge, and biological process plants. Lead
concentration in POTW effluents ranged from 0.003 to 1 . 8 mg/1
(mean = 0.106 mg/1, standard deviation = 0.222).
Application of lead-containing sludge to cropland should not lead
to uptake by crops under most conditions because normally lead is
strongly bound by soil. However, under the unusual condition of
low pH (less than 5.5) and low concentrations of labile phos-
phorus, lead solubility is increased and plants can accumulate
lead.
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Mercury (123). Mercury is an elemental metal rarely found in
nature as the free metal. Mercury is unique among metals as it
remains a liquid down to about 39 degrees below zero. It is
relatively inert chemically and is insoluble in water. The
principal ore is cinnabar (HgS).
Mercury is used industrially as the metal and as mercurous and
mercuric salts and compounds. Mercury is used in several types
of batteries. Mercury released to the aqueous environment is
subject to biomethylation - conversion to the extremely toxic
methyl mercury.
Mercury can be introduced into the body through the skin and the
respiratory system as the elemental vapor. Mercuric salts are
highly toxic to humans and can be absorbed through the gastro-
intestinal tract. Fatal doses can vary from 1 to 30 grams.
Chronic toxicity of methyl mercury is evidenced primarily by
neurological symptoms. Some mercuric salts cause death by kidney
failure.
Mercuric salts are extremely toxic to fish and other aquatic
life. Mercuric chloride is more lethal than copper, hexavalent
chromium, zinc, nickel, and lead towards fish and aquatic life.
In the food cycle, algae containing mercury up to 100 times the
concentration in the surrounding sea water are eaten by fish
which further concentrate the mercury. Predators that eat the
fish in turn concentrate the mercury even further.
For the protection of human health from the toxic properties of
mercury ingested through water and through contaminated aquatic
organisms the ambient water criterion is determined to be 0.0002
rag/1.
Mercury is not destroyed when treated by a POTW, and will either
pass through to the POTW effluent or be incorporated into the
POTW sludge. At low concentrations it may reduce POTW removal
efficiencies, and at high concentrations it may upset the POTW
operation.
The influent concentrations of mercury to a POTW have been
observed by the EPA to range from 0.002 to 0.24 mg/1, with a
median concentration of 0.001 mg/1. Mercury has been reported in
the literature to have inhibiting effects upon an activated
sludge POTW at levels as low as 0.1 mg/1. At 5 mg/1 of mercury,
losses of COD removal efficiency of 14 to 40 percent have been
reported, while at 10 mg/1 loss of removal of 59 percent has been
reported. Upset of an activated sludge POTW is reported in the
literature to occur near 200 mg/1. The anaerobic digestion pro-
cess is much less affected by the presence of mercury, with
inhibitory effects being reported at 1,365 mg/1.
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In a study of 22 POTW facilities having secondary treatment, the
range of removal of mercury from the influent to the POTW ranged
from 4 to 99 percent with median removal of 41 percent. Thus
significant pass through of mercury may occur.
In sludges, mercury content may be high if industrial sources of
mercury contamination are present. Little is known about the
form in which mercury occurs in sludge. Mercury may undergo
biological methylation in sediments, but no methylation has been
observed in soils, mud, or sewage sludge.
The mercury content of soils not receiving additions of POTW
sewage sludge lie in the range from 0.01 to 0.5 mg/kg. In soils
receiving POTW sludges for protracted periods, the concentration
of mercury has been observed to approach 1.0 mg/kg. In the soil,
mercury enters into reactions with the exchange complex of clay
and organic fractions, forming both ionic and covalent bonds.
Chemical and microbiological degradation of mercurials can take
place side by side in the soil, and the products - ionic or
molecular - are retained by organic matter and clay or may be
volatilized if gaseous. Because of the high affinity between
mercury and the solid soil surfaces, mercury persists in the
upper layer of the soil.
Mercury can enter plants through the roots, it can readily move
to other parts of the plant, and it has been reported to cause
injury to plants. In many plants mercury concentrations range
from 0.01 to 0.20 mg/kg, but when plants are supplied with high
levels of mercury, these concentrations can exceed 0.5 mg/kg.
Bioconcentration occurs in animals ingesting mercury in food.
Nickel (124). Nickel is seldom found in nature as the pure ele-
mental metal. It is a relatively plentiful element and is widely
distributed throughout the earth's crust. It occurs in marine
organisms and is found in the oceans. The chief commercial ores
for nickel are pentlandite [(Fe,Ni)983], and a lateritic ore
consisting of hydrated nickel-iron-magnesium silicate.
Nickel has many and varied uses. It is used in alloys and as the
pure metal. Nickel salts are used for electroplating baths.
The toxicity of nickel to man is thought to be very low, and sys-
temic poisoning of human beings by nickel or nickel salts is
almost unknown. In non-human mammals nickel acts to inhibit
insulin release, depress growth, and reduce cholesterol. A high
incidence of cancer of the lung and nose has been reported in
humans engaged in the refining of nickel.
Nickel salts can kill fish at very low concentrations. However,
nickel has been found to be less toxic to some fish than copper,
zinc, and iron. Nickel is present in coastal and open ocean
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water at concentrations in the range of 0.0001 to 0.006 mg/1
although the most common values are 0.002 to 0.003 mg/1. Marine
animals contain up to 0.4 mg/1 and marine plants contain up to 3
mg/1. Higher nickel concentrations have been reported to cause
reduction in photosynthetic activity of the giant kelp. A low
concentration was found to kill oyster eggs.
For the protection of human health based on the toxic properties
of nickel ingested through water and through contaminated aquatic
organisms, the ambient water criterion is determined to be 0.0134
mg/1. If contaminated aquatic organisms are consumed, excluding
consumption of water, the ambient water criterion is determined
to be 0.100 mg/1. Available data show that adverse effects on
aquatic life occur for total recoverable nickel concentrations as
low as 0.0071 mg/1 as a 24-hour average.
Nickel is not destroyed when treated in a POTW, but will either
pass through to the POTW effluent or be retained in the POTW
sludge. It can interfere with POTW treatment processes and can
also limit the usefulness of municipal sludge.
Nickel salts have caused inhibition of the biochemical oxidation
of sewage in a POTW. In a pilot plant, slug doses of nickel
significantly reduced normal treatment efficiencies for a few
hours, but the plant acclimated itself somewhat to the slug dos-
age and appeared to achieve normal treatment efficiencies within
40 hours. It has been reported that the anaerobic digestion pro-
cess is inhibited only by high concentrations of nickel, while a
low concentration of nickel inhibits the nitrification process.
The influent concentration of nickel to a POTW has been observed
by the EPA to range from 0.01 to 3.19 mg/1, with a median of 0.33
mg/1. In a study of 190 POTW facilities, nickel pass-through was
greater than 90 percent for 82 percent of the primary plants.
Median pass-through for trickling filter, activated sludge, and
biological process plants was greater than 80 percent. POTW
effluent concentrations ranged from 0.002 to 40 mg/1 (mean =
0.410, standard deviation - 3.279).
Nickel not passed through the POTW will be incorporated into the
sludge. In a recent two-year study of eight cities, four of the
cities had median nickel concentrations of over 350 mg/kg, and
two were over 1,000 mg/kg. The maximum nickel concentration
observed was 4,010 mg/kg.
Nickel is found in nearly all soils, plants, and waters. Nickel
has no known essential function in plants. In soils, nickel
typically is found in the range from 10 to 100 mg/kg. Various
environemntal exposures to nickel appear to correlate with
increased incidence of tumors in man. For example, cancer in the
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maxillary antrum of snuff users may result from using plant
materials grown on soil high in nickel.
Nickel toxicity may develop in plants from application of sewage
sludge on acid soils. Nickel has caused reduction of yields for
a variety of crops including oats, mustard, turnips, and cabbage.
In one study nickel decreased the yields of oats significantly at
100 mg/kg.
Whether nickel exerts a toxic effect on plants depends on several
soil factors, the amount of nickel applied, and the contents of
other metals in the sludge. Unlike copper and zinc, which are
more available from inorganic sources than from sludge, nickel
uptake by plants seems to be promoted by the presence of the
organic matter in sludge. Soil treatments, such as liming,
reduce the solubility of nickel. Toxicity of nickel to plants is
enhanced in acidic soils.
Selenium (125). Selenium is a non-metallic element existing in
several allotropic forms. Gray selenium, which has a metallic
appearance, is the stable form at ordinary temperatures and melts
at 220°C. Selenium is a major component of 38 minerals and a
minor component of 37 others found in various parts of the world.
Most selenium is obtained as a by-product of precious metals
recovery from electrolytic copper refinery slimes. U.S. annual
production at one time reached one million pounds.
Principal uses of selenium are in semi-conductors, pigments,
decoloring of glass, zerography, and metallurgy. It also is used
to produce ruby glass used in signal lights. Several selenium
compounds are important oxidizing agents in the synthesis of
organic chemicals and drug products.
While results of some studies suggest that selenium may be an
essential element in human nutrition, the toxic effects of
selenium in humans are well established. Lassitude, loss of
hair, discoloration and loss of fingernails are symptoms of
selenium poisoning. In a fatal, case of ingestion of a larger
dose of selenium acid, peripheral vascular collapse, pulmonary
edema, and coma occurred. Selenium produces mutagenic and tera-
togenic effects, but it has not been established as exhibiting
carcinogenic activity.
For the protection of human health from the toxic properties of
selenium ingested through water and through contaminated aquatic
organisms, the ambient water criterion is determined to be 0.010
mg/1, i.e., the same as the drinking water standard. Available
data show that adverse effects on aquatic life occur at concen-
trations higher than that cited for human toxicity.
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Very few data are available regarding the behavior of selenium in
a POTW. One EPA survey of 103 POTW facilities revealed one POTW
using biological treatment and having selenium in the influent.
Influent concentration was 0.0025 mg/1, effluent concentration
was 0.0016 mg/1, giving a removal of 37 percent. It is not known
to be inhibitory to POTW processes. In another study, sludge
from POTW facilities in 16 cities was found to contain from 1.8
to 8.7 mg/kg selenium, compared to 0.01 to 2 mg/kg in untreated
soil. These concentrations of selenium in sludge present a
potential hazard for humans or other mammals eating crops grown
on soil treated with selenium-containing sludge.
Silver (126). Silver is a soft, lustrous, white metal that is
insoluble in water and alkali. In nature, silver is found in the
elemental state (native silver) and combined in ores such as
argentite (Ag2S), horn silver (AgCl), proustite (Ag3AsS3),
and pyrargyrite (Ag3SbS3). Silver is used extensively in
several industries, among them electroplating.
Metallic silver is not considered to be toxic, but most of its
salts are toxic to a large number of organisms. Upon ingestion
by humans, many silver salts are absorbed in the circulatory sys-
tem and deposited in various body tissues, resulting in general-
ized or sometimes localized gray pigmentation of the skin and
mucous membranes known as argyria. There is no known method for
removing silver from the tissues once it is deposited, and the
effect is cumulative.
Silver is recognized as a bactericide and doses from 0.000001 to
0.0005 mg/1 have been reported as sufficient to sterilize water.
The criterion for ambient water to protect human health from the
toxic properties of silver ingested through water and through
contaminated aquatic organisms is 0.010 mg/1.
The chronic toxic effects of silver on the aquatic environment
have not been given as much attention as many other heavy metals.
Data from existing literature support the fact that silver is
very toxic to aquatic organisms. Despite the fact that silver is
nearly the most toxic of the heavy metals, there are insufficient
data to adequately evaluate even the effects of hardness on
silver toxicity. There are no data available on the toxicity of
different forms of silver.
There is no available literature on the incidental removal of
silver by a POTW. An incidental removal of about 50 percent is
assumed as being representative. This is the highest average
incidental removal of any metal for which data are available.
(Copper has been indicated to have a median incidental removal
rate of 49 percent.)
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Bioaccumulation and concentration of silver from sewage sludge
has not been studied to any great degree. There is some indica-
tion that silver could be bioaccumulated in mushrooms to the
extent that there could be adverse physiological effects on
humans if they consumed large quantities of mushrooms grown in
silver enriched soil. The effect, however, would tend to be
unpleasant rather than fatal.
There are little summary data available on the quantity of silver
discharged to a POTW. Presumably there would be a tendency to
limit its discharge from a manufacturing facility because of its
high intrinsic value.
Thallium (127). Thallium is a soft, silver-white, dense,
malleable metal. Five major minerals contain 15 to 85 percent
thallium, but they are not of commercial importance because the
metal is produced in sufficient quantity as a by-product of lead-
zinc smelting of sulfide ores. Thallium melts at 304°C. U.S.
annual production of thallium and its compounds is estimated to
be 1,500 pounds.
Industrial uses of thallium include the manufacture of alloys,
electronic devices and special glass. Thallium catalysts are
used for industrial organic syntheses.
Acute thallium poisoning in humans has been widely described.
Gastrointestinal pains and diarrhea are followed by abnormal
sensation in the legs and arms, dizziness, and, later, loss of
hair. The central nervous system is also affected. Somnolence,
delerium or coma may occur. Studies on the teratogenicity of
thallium appear inconclusive; no studies on mutagenicity were
found; and no published reports on carcinogenicity of thallium
were found.
For the protection of human health from the toxic properties of
thallium ingested through water and contaminated aquatic
organisms, the ambient water criterion is 0.004 mg/1.
No reports were found regarding the behavior of thallium in a
POTW. It will not be degraded, therefore it must pass through to
the effluent or be removed with the sludge. However, since the
sulfide (T1S) is very insoluble, if appreciable sulfide is
present dissolved thallium in the influent to a POTW may be pre-
cipitated into the sludge. Subsequent use of sludge bearing
thallium compounds as a soil amendment to crop bearing soils may
result in uptake of this element by food plants. Several leafy
garden crops (cabbage, lettuce, leek, and endive) exhibit rela-
tively higher concentrations of thallium than other foods such as
meat.
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Zinc (128). Zinc occurs abundantly in the earth's crust, con-
centrated in ores. It is readily refined into the pure, stable,
silver-white metal. In addition to its use in alloys, zinc is
used as a protective coating on steel. It is applied by hot dip-
ing (i.e., dipping the steel in molten zinc) or by electroplat-
ing.
Zinc can have an adverse effect on man and animals at high con-
centrations. Zinc at concentrations in excess of 5 mg/1 causes
an undesirable taste which persists through conventional treat-
ment. For the prevention of adverse effects due to these organo-
leptic properties of zinc, 5 mg/1 was adopted for the ambient
water criterion. Available data show that adverse effects on
aquatic life occur at concentrations as low as 0.047 mg/1 as a
24-hour average.
Toxic concentrations of zinc compounds cause adverse changes in
the morphology and physiology of fish. Lethal concentrations in
the range of 0.1 mg/1 have been reported. Acutely toxic concen-
trations induce cellular breakdown of the gills, and possibly the
clogging of the gills with mucous. Chronically toxic concentra-
tions of zinc compounds cause general enfeeblement and widespread
histological changes to many organs, but not to gills. Abnormal
swimming behavior has been reported at 0.04 mg/1. Growth and
maturation are retarded by zinc. It has been observed that the
effects of zinc poisoning may not become apparent immediately, so
that fish removed from zinc-contaminated water may die as long as
48 hours after removal.
In general, salmonoids are most sensitive to elemental zinc in
soft water; the rainbow trout is the most sensitive in hard
waters. A complex relationship exists between zinc concentra-
tion, dissolved zinc concentration, pH, temperature, and calcium
and magnesium concentration. Prediction of harmful effects has
been less than reliable and controlled studies have not been
extensively documented.
The major concern with zinc compounds in marine waters is not
with acute lethal effects, but rather with the long-term sub-
lethal effects of the metallic compounds and complexes. Zinc
accumulates in some marine species, and marine animals contain
zinc in the range of 6 to 1,500 mg/kg. From the point of view of
acute lethal effects, invertebrate marine animals seem to be the
most sensitive organism tested.
Toxicities of zinc in nutrient solutions have been demonstrated
for a number of plants. A variety of fresh water plants tested
manifested harmful symptoms at concentrations of 0.030 to 21.6
mg/1. Zinc sulfate has also been found to be lethal to many
plants and it could impair agricultural uses of the water.
190
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Zinc is not destroyed when treated by a POTW, but will either
pass through to the POTW effluent or be retained in the POTW
sludge. It can interfere with treatment processes in the POTW
and can also limit the usefulness of municipal sludge.
In slug doses, and particularly in the presence of copper, dis-
solved zinc can interfere with or seriously disrupt the operation
of POTW biological processes by reducing overall removal effi-
ciencies, largely as a result of the toxicity of the metal to
biological organisms. However, zinc solids in the form of
hydroxides or sulfides do not appear to interfere with biological
treatment processes, on the basis of available data. Such solids
accumulate in the sludge.
The influent concentrations of zinc to a POTW have been observed
by the EPA to range from 0.017 to 3.91 mg/1, with a median con-
centration of 0.33 mg/1. Primary treatment is not efficient in
removing zinc; however, the microbial floe of secondary treatment
readily adsorbs zinc.
In a study of 258 POTW facilities, the median pass-through values
were 70 to 88 percent for primary plants, 50 to 60 percent for
trickling filter and biological process plants, and 30 to 40 per-
cent for activated process plants. POTW effluent concentrations
of zinc ranged from 0.003 to 3.6 mg/1 (mean = 0.330, standard
deviation = 0.464).
The zinc which does not pass through the POTW is retained in the
sludge. The presence of zinc in sludge may limit its use on
cropland. Sewage sludge contains 72 to over 30,000 mg/kg of
zinc, with 3,366 mg/kg as the mean value. These concentrations
are significantly greater than those normally found in soil,
which range from 0 to 195 mg/kg, with 94 mg/kg being a common
level. Therefore, application of sewage sludge to soil will
generally increase the concentration of zinc in the soil. Zinc
can be toxic to plants, depending upon soil pH. Lettuce, toma-
toes, turnips, mustard, kale, and beets are especially sensitive
to zinc contamination.
Oil and Grease. Oil and grease are taken together as one pollu-
tant parameter. This is a conventional pollutant and some of its
components are:
1. Light Hydrocarbons - These include light fuels such as
gasoline, kerosene, and jet fuel, and miscellaneous solvents used
for industrial processing, degreasing, or cleaning purposes. The
presence of these light hydrocarbons may make the removal of
other heavier oil wastes more difficult.
191
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2. Heavy Hydrocarbons, Fuels, and Tars - These include the
crude oils, diesel oils, #6 fuel oil, residual oils, slop oils,
and in some cases, asphalt and road tar.
3. Lubricants and Cutting Fluids - These generally fall
into two classes: non-emulsifiable oils such as lubricating oils
and greases and emulsifiable oils such as water soluble oils,
rolling oils, cutting oils, and drawing compounds. Emulsifiable
oils may contain fat, soap, or various other additives.
4. Vegetable and Animal Fats and Oils - These originate
primarily from processing of foods and natural products.
These compounds can settle or float and may exist as solids or
liquids depending upon factors such as method of use, production
process, and temperature of water.
Oil and grease even in small quantities cause troublesome taste
and odor problems. Scum lines from these agents are produced on
water treatment basin walls and other containers. Fish and water
fowl are adversely affected by oils in their habitat. Oil emul-
sions may adhere to the gills of fish causing suffocation, and
the flesh of fish is tainted when microorganisms that were
exposed to waste oil are eaten. Deposition of oil in the bottom
sediments of water can serve to inhibit normal benthic growth.
Oil and grease exhibit an oxygen demand.
Many of the toxic organic pollutants will be found distributed
between.the oil phase and the aqueous phase in industrial waste-
waters. The presence of phenols, PCB's, PAH's, and almost any
other organic pollutant in the oil and grease make characteriza-
tion of this parameter almost impossible. However, all of these
other organics add to the objectionable nature of the oil and
grease.
Levels of oil and grease which are toxic to aquatic organisms
vary greatly, depending on the type and the species susceptibil-
ity. However, it has been reported that crude oil in concentra-
tions as low as 0.3 mg/1 is extremely toxic to freshwater fish.'
It has been recommended that public water supply sources be
essentially free from oil and grease.
Oil and grease in quantities of 100 1/sq km show up as a sheen on
the surface of a body of water. The presence of oil slicks
decreases the aesthetic value of a waterway.
Oil and grease is compatible with a POTW activated sludge process
in limited quantity. However, slug loadings or high concentra-
tions of oil and grease interfere with biological treatment pro-
cesses. The oils coat surfaces and solid particles, preventing
access of oxygen, and sealing in some microorganisms. Land
19?
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spreading of POTW sludge containing oil and grease uncontaminated
by toxic pollutants is not expected to affect crops grown on the
treated land, or animals eating those crops.
pH. Although not a specific pollutant, pH is related to the
acidity or alkalinity of a wastewater stream. It is not, how-
ever, a measure of either. The term pH is used to describe the
hydrogen ion concentration (or activity) present in a given solu-
tion. Values for pH range from 0 to 14, and these numbers are
the negative logarithms of the hydrogen ion concentrations. A pH
of 7 indicates neutrality. Solutions with a pH above 7 are alka-
line, while those solutions with a pH below 7 are acidic. The
relationship of pH and acidity and alkalinity is not necessarily
linear or direct. Knowledge of the water pH is useful in deter-
mining necessary measures for corrosion control, sanitation, and
disinfection. Its value is also necessary in the treatment of
industrial wastewaters to determine amounts of chemicals required
to remove pollutants and to measure their effectiveness. Removal
of pollutants, especially dissolved solids is affected by the pH
of the wastewater.
Waters with a pH below 6.0 are corrosive to water works struc-
tures, distribution lines, and household plumbing fixtures and
can thus add constituents to drinking water such as iron, copper,
zinc, cadmium, and lead. The hydrogen ion concentration can
affect the taste of the water, and at a low pH water tastes sour.
The bactericidal effect of chlorine is weakened as the pH
increases, and it is advantageous to keep the pH close to 7.0.
This is significant for providing safe drinking water.
Extremes of pH or rapid pH changes can exert stress conditions or
kill aquatic life outright. Even moderate changes from accept-
able criteria limits of pH are deleterious to some species.
The relative toxicity to aquatic life of many materials is
increased by changes in the water pH. For example, metallocya-
nide complexes can increase a thousand-fold in toxicity with a
drop of 1.5 pH units.
Because of the universal nature of pH and its effect on water
quality and treatment, it is selected as a pollutant parameter
for many industry categories. A neutral pH range (approximately
6 to 9) is generally desired because either extreme beyond this
range has a deleterious effect on receiving waters or the pollu-
tant nature of other wastewater constituents.
Pretreatment for regulation of pH is covered by the "General Pre-
treatment Regulations for Existing and New Sources of Pollution,"
40 CFR 403.5. This section prohibits the discharge to a POTW of
"pollutants which will cause corrosive structural damage to the
POTW but in no case discharges with pH lower than 5.0 unless the
works is specially designed to accommodate such discharges."
193
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Total Suspended Solids (TSS). Suspended solids include both
organic and inorganic materials. The inorganic compounds include
sand, silt, and clay. The organic fraction includes such materi-
als as grease, oil, tar, and animal and vegetable waste products.
These solids may settle out rapidly, and bottom deposits are
often a mixture of both organic and inorganic solids. Solids may
be suspended in water for a time and then settle to the bed of
the stream or lake. These solids discharged with man's wastes
may be inert, slowly biodegradable materials, or rapidly decom-
posable substances. While in suspension, suspended solids
increase the turbidity of the water, reduce light penetration,
and impair the photosynthetic activity of aquatic plants.
Suspended solids in water interfere with many industrial pro-
cesses and cause foaming in boilers and incrustations on equip-
ment exposed to such water, especially as the temperature rises.
They are undesirable in process water used in the manufacture of
steel, in the textile industry, in laundries, in dyeing, and in
cooling systems.
Solids in suspension are aesthetically displeasing. When they
settle to form sludge deposits on the stream or lake bed, they
are often damaging to the life in the water. Solids, when trans-
formed to sludge deposit, may do a variety of damaging things,
including blanketing the stream or lake bed and thereby destroy-
ing the living spaces for those benthic organisms that would
otherwise occupy the habitat. When of an organic nature, solids
use a portion or all of the dissolved oxygen available in the
area. Organic materials also serve as a food source for
sludgeworms and associated organisms.
Disregarding any toxic effect attributable to substances leached
out by water, suspended solids may kill fish and shellfish by
causing abrasive injuries and by clogging the gills and respira-
tory passages of various aquatic fauna. Indirectly, suspended
solids are inimical to aquatic life because they screen out
light, and they promote and maintain the development of noxious
conditions through oxygen depletion. This results in the killing
of fish and fish food organisms. Suspended solids also reduce
the recreational value of the water.
Total suspended solids is a traditional pollutant which is com-
patible with a well-run POTW. This pollutant with the exception
of those components which are described elsewhere in this sec-
tion, e.g., heavy metal components, does not interfere with the
operation of a POTW. However, since a considerable portion of
the innocuous TSS may be inseparably bound to the constituents
which do interfere with POTW operation, or produce unusable
sludge, or subsequently dissolve to produce unacceptable POTW
effluent, TSS may be considered a toxic waste.
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Aluminum. Aluminum, a nonconventional pollutant, is the most
common metallic element in the earth's crust, and the third most
abundant element (8.1 percent). It is never found free in
nature. Most rocks and various clays contain aluminum in the
form of aluminosilicate minerals. Generally, aluminum is first
converted to alumina (A^C^) from bauxite ore. The alumina
then undergoes electrolytic reduction to form the metal. Alumi-
num powders (used in explosives, fireworks, and rocket fuels)
form flammable mixtures in the air. Aluminum metal resists
corrosion under many conditions by forming a protective oxide
film on the surface. This oxide layer corrodes rapidly in strong
acids and alkalis, and by the electrolytic action of other metals
with which it comes in contact. Aluminum is light, malleable,
ductile, possesses high thermal and electrical conductivity, and
is non-magnetic. It can be formed, machined, or cast. Aluminum
is used in the building and construction, transportation, and the
container and packaging industries and competes with iron and
steel in these markets. Total U.S. production of primary alumi-
num in 1981 was 4,948,000 tons. Secondary aluminum (from old
scrap) production in 1981 was 886,000 tons.
Aluminum is soluble under both acidic and basic conditions, with
environmental transport occurring most readily under these condi-
tions. In water, aluminum can behave as an acid or base, can
form ionic complexes with other substances, and can polymerize,
depending on pH and the dissolved substances in water. Alumi-
num's high solubility at acidic pH conditions makes it readily
available for accumulation in aquatic life. Acidic waters con-
sistently contain higher levels of soluble aluminum than neutral
or alkaline waters. Loss of aquatic life in acidified lakes and
streams has been shown to be due in part to increased concentra-
tions of aluminum in waters as a result of leaching of aluminum
from soil by acidic rainfall.
Aluminum has been found to be toxic to freshwater and marine
aquatic life. In freshwaters acute toxicity and solubility
increases as pH levels increase above pH 7. This relationship
also appears to be true as the pH levels decrease below ptt 7.
Chronic effects of aluminum on aquatic life have also been docu-
mented. Aluminum has been found to be toxic to certain plants.
A water quality standard for aluminum was established (U.S.
Federal Water Pollution Control Administration, 1968) for inter-
state agricultural and irrigation waters, which set a trace
element tolerance at 1 mg/1 for continuous use on all soils and
20 mg/1 for short term use on fine-textured soils.
There are no reported adverse physiological effects on man from
exposure to low concentrations of aluminum in drinking water.
Large concentrations of aluminum in the human body, however, are
alleged to cause changes in behavior. Aluminum compounds,
195
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especially aluminum sulfate, are major coagulants used in the
treatment of drinking water. Aluminum is not among the metals
for which a drinking water standard has been established.
The highest aluminum concentrations in animals and humans occur
in the lungs, mostly from the inhalation of airborne particulate
matter. Pulmonary fibrosis has been associated with the inhala-
tion of very fine particles of aluminum flakes and powders among
workers in the explosives and fireworks industries. An occupa-
tional exposure Threshold Limit Value (TLV) of 5 mg/m^ is
recommended for pyro powders to prevent lung changes, and a
Time-Weighted Average (TWA) of 10 mg/m^ is recommended for
aluminum dust. High levels of aluminum have been found in the
brains, muscles, and bones of patients with chronic renal failure
who are being treated with aluminum hydroxide, and high brain
levels of aluminum are found in those suffering from Alzheimers
disease (presenile dementia) which manifests behavioral changes.
Aluminum and some of its compounds used in food preparation and
as food additives are generally recognized as safe and are sanc-
tioned by the Food and Drug Administration. No limits on alumi-
num content in food and beverage products have been established.
Aluminum has no adverse effects on POTW operation at concentra-
tions normally encountered. The results of an EPA study of 50
POTWs revealed that 49 POTWs contained aluminum with effluent
concentrations ranging from less than 0.1 mg/1 to 1.07 mg/1 and
with an average removal of 82 percent.
Ammonia. Ammonia (chemical formula NH3) is a nonconventional
pollutant. It is a colorless gas with a very pungent odor,
detectable at concentrations of 20 ppm in air by the nose, and is
very soluble in water (570 gm/1 at 25°C)'. Ammonia is produced
industrially in very large quantities (nearly 20 million tons
annually in the U.S.). It is converted to ammonium compounds or
shipped in the liquid form (it liquifies at -33°C). Ammonia also
results from natural processes. Bacterial action on nitrates or
nitrites, as well as dead plant and animal tissue and animal
wastes produces ammonia. Typical domestic wastewaters contain 12
to 50 mg/1 ammonia.
The principal use of ammonia and its compounds is as fertilizer.
High amounts are introduced into soils and the water runoff from
agricultural land by this use. Smaller quantities of ammonia are
used as a refrigerant. Aqueous ammonia (2 to 5 percent solution)
is widely used as a household cleaner. Ammonium compounds find a
variety of uses in various industries, as an example, ammonium
hydroxide is used as a reactant in the purification of tungsten.
Ammonia is toxic to humans by inhalation of the gas or ingestion
of aqueous solutions. The ionized form, ammonium (NH4+), is
196
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less toxic than the unionized form. Ingestion of as little as
one ounce of household ammonia has been reported as a fatal dose.
Whether inhaled or ingested, ammonia acts distructively on mucous
membrane with resulting loss of function. Aside from breaks in
liquid ammonia refrigeration equipment, industrial hazard from
ammonia exists where solutions of ammonium compounds may be
accidently treated with a strong alkali, releasing ammonia gas.
As little as 150 ppm ammonia in air is reported to cause laryn-
geal spasms, and inhalation of 5,000 ppm in air is considered
sufficient to result in death.
The behavior of ammonia in POTW is well documented because it is
a natural component of domestic wastewaters. Only very high con-
centrations of ammonia compounds could overload POTW. One study
has shown that concentrations of unionized ammonia greater than
90 mg/1 reduce gasification in anaerobic digesters and concentra-
tions of 140 mg/1 stop digestion completely. Corrosion of copper
piping and excessive consumption of chlorine also result from
high ammonia concentrations. Interference with aerobic nitrifi-
cation processes can occur when large concentrations of ammonia
suppress dissolved oxygen. Nitrites are then produced instead of
nitrates. Elevated nitrite concentrations in drinking water are
known to cause infant methemoglobinemia.
Fluoride. Fluoride ion (F-) is a nonconventional pollutant.
Fluorine is an extremely reactive, pale yellow, gas which is
never found free in nature. Compounds of fluorine - fluorides -
are found widely distributed in nature. The principal minerals
containing fluorine are fluorspar (CaF2) and cryolite
(Na£AlF5). Although fluorine is produced commercially in
small quantities by electrolysis of potassium bifluoride in anhy-
drous hydrogen fluoride, the elemental form bears little relation
to the combined ion. Total production of fluoride chemicals in
the U.S. is difficult to estimate because of the varied uses.
Large volume usage compounds are: calcium fluoride (estimated
1,500,000 tons in U.S.) and sodium fluoraluminate (estimated
100,000 tons in U.S.). Some fluoride compounds and their uses
are sodium fluoroaluminate - aluminum production; calcium fluor-
ide - steelmaking, hydrofluoric acid production, enamel, iron
foundry; boron trifluoride - organic synthesis; antimony penta-
fluoride - fluorocarbon production; fluoboric acid and fluobor-
ates - electroplating; perchloryl fluoride (C103F) - rocket
fuel oxidizer; hydrogen fluoride - organic fluoride manufacture,
pickling acid in stainless steelmaking, manufacture of aluminum
fluoride; sulfur hexafluoride - insulator in high voltage trans-
formers ; polytetrafluoroethylene - inert plastic. Sodium
fluoride is used at a concentration of about 1 pm in many public
drinking water supplies to prevent tooth decay in children.
The toxic effects of fluoride on humans include severe gastroen-
teritis, vomiting, diarrhea, spasms, weakness, thirst, failing
197
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pulse and delayed blood coagulation. Most observations of toxic
effects are made on individuals who intentionally or accidentally
ingest sodium fluoride intended for use as rat poison or insecti-
cide. Lethal doses for adults are estimated to be as low as
2.5 g. At 1.5 ppm in drinking water, mottling of tooth enamel is
reported, and 14 ppm, consumed over a period of years, may lead
to deposition of calcium fluoride in bone and tendons.
Fluorides found in irrigation waters in high concentrations have
caused damage to certain plants exposed to these waters. Chronic
fluoride poisoning of livestock has been observed. Fluoride from
waters apparently does not accumulate in soft tissue to a signi-
ficant degree; it is transferred to a very small extent into the
milk and to a somewhat greater degree in eggs. Data for fresh
water indicate that fluorides are toxic to fish.
Very few data are available on the behavior of fluoride in POTW.
Under usual operating conditions in POTW, fluorides pass through
into the effluent. Very little of the fluoride entering conven-
tional primary and secondary treatment processes is removed. In
one study of POTW influents conducted by the U.S. EPA, nine POTW
reported concentrations of fluoride ranging from 0.7 mg/1 to 1.2
mg/1, which is the range of concentrations used for fluoridated
drinking water.
Phenols (Total). "Total Phenols" is a nonconventional pollutant
parameter. Total phenols is the result of analysis using the
4-AAP (4-aminoantipyrene) method. This analytical procedure
measures the color development of reaction products between 4-AAP
and some phenols. The results are reported as phenol. Thus
"total phenol" is not total phenols because many phenols (notably
nitrophenols) do not react. Also, since each reacting phenol
contributes to the color development to a different degree, and
each phenol has a molecular weight different from others and from
phenol itself, analyses of several mixtures containing the same
total concentration in mg/1 of several phenols will give differ-
ent numbers depending on the proportions in the particular
mixture.
Despite these limitations of the analytical method, total phenols
is a useful parameter when the mix of phenols is relatively con-
stant and an inexpensive monitoring method is desired. In any
given plant or even in an industry subcategory, monitoring of
"total phenols" provides an indication of the concentration of
this group of priority pollutants as well as those phenols not
selected as priority pollutants. A further advantage is that the
method is widely used in water quality determinations.
In an EPA survey of 103 POTW the concentration of "total phenols"
ranged from 0.0001 mg/1 to 0.176 mg/1 in the influent, with a
median concentration of 0.016 mg/1. Analysis of effluents from
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22 of these same POTW which had biological treatment meeting
secondary treatment performance levels showed "total phenols"
concentrations ranging from 0 mg/1 to 0.203 mg/1 with a median of
0.007. Removals were 64 to 100 percent with a median of 78 per-
cent.
It must be recognized, however, that six of the 11 priority pol-
lutant phenols could be present in high concentrations and not be
detected. Conversely, it is possible, but not probable, to have
a high "total phenol concentration without any phenol itself or
any of the 10 other priority pollutant phenols present. A char-
acterization of the phenol mixture to be monitored to establish
constancy of composition will allow "total phenols" to be used
with confidence.
SUMMARY OF POLLUTANT SELECTION
After examining the sampling data, pollutants and pollutant
parameters were selected by subcategory for further consideration
for limitation. The selection of a pollutant was based on the
concentration of the pollutant in the raw sampling data and the
frequency of occurrence above concentrations considered treata-
ble. The pollutants selected under this rationale are listed
below. The analysis that led to the selection of these toxic
pollutants and the exclusion of pollutants under Paragraph 8 is
presented in Section VI of each subcategory supplement.
Pollutants Selected for Further Consideration by Subcategory
Bauxite Refining
21. 2,4,6-trichlorophenol
24. 2-chlorophenol
31. 2,4-dichlorophenol
57. 2-nitrophenol
58. 4-nitrophenol
65. phenol
phenols (4-AAP)
pH
Primary Antimony Subcategory
1 1 4. antimony
115. arsenic
118. cadmium
120. copper
122. lead
123. mercury
128. zinc
total suspended solids (TSS)
PH
199
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Primary Beryllium
117. beryllium
119. chromium
120. copper
fluoride
total suspended solids (TSS)
pH
Primary Boron
118. cadmium
119. chromium (total)
122. lead
124. nickel
127. thallium
128. zinc
boron
total suspended solids
pH
Primary Cesium and Rubidium
114.
115.
117.
118.
119.
120.
122.
124.
126.
127.
128.
antimony
arsenic
beryllium
cadmium
chromium (total)
copper
lead
nickel
silver
thallium
zinc
total suspended solids
pH
(TSS)
(TSS)
Primary and Secondary Germanium and Gallium
114. antimony
115. arsenic
118. cadmium
119. chromium
120. copper
122. lead
124. nickel
125. selenium
126. silver
127. thallium
128. zinc
200
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fermanium
luoride
total suspended solids (TSS)
pH
Secondary Indium
118. cadmium
119. chromium
122. lead
124. nickel
125. selenium
126. silver
127. thallium
128. zinc
indium
total suspended solids (TSS)
pH
Secondary Mercury
122. lead
123. mercury
127. thallium
128. zinc
total suspended solids (TSS)
PH
Primary Molybdenum and Rhenium
11 5. arsenic
119. chromium (total)
120. copper
122. lead
124. nickel
125. selenium
128. zinc
molybdenum
ammonia (as N)
total suspended solids (TSS)
pH
Secondary Molybdenum and Vanadium
1 14. antimony
115. arsenic
117. beryllium
118. cadmium
119. chromium
122. lead
201
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124. nickel
128. zinc
molybdenum
ammonia (as N)
total suspended solids (TSS)
pH
Primary Nickel and Cobalt
120. copper
124. nickel
128. zinc
cobalt
ammonia (as N)
total suspended solids (TSS)
pH
Secondary Nickel
115. arsenic
119. chromium
120. copper
124. nickel
128. zinc
total suspended solids (TSS)
pH
Primary Precious Metals and Mercury
115. arsenic
118. cadmium
119. chromium
120. copper
122. lead
123. mercury
124. nickel
125. selenium
126. silver
127. thallium
128. zinc
oil and grease
total suspended solids (TSS)
pH
Secondary Precious Metals
114. antimony
115. arsenic
118. cadmium
119. chromium
202
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120. copper
121. cyanide
122. lead
124. nickel
125. selenium
126. silver
127. thallium
128. zinc
ammonia (as N)
total suspended solids (TSS)
pH
Primary Rare Earth Metals
4. benzene
9. hexachlorobenzene
11 5. arsenic
118. cadmium
119. chromium (total)
120. copper
122. lead
124. nickel
125. selenium
126. silver
127. thallium
128. zinc
total suspended solids (TSS)
pH
Secondary Tantalum
11 4. antimony
120. copper
122. lead
124. nickel
126. silver
128. zinc
total suspended solids (TSS)
pH
Primary and Secondary Tin
1 1 4. antimony
115. arsenic
118. cadmium
119. chromium
120. copper
121. cyanide
122. lead
124. nickel
203
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125. selenium
126. silver
127. thallium
128. zinc
tin
ammonia (as N)
fluoride
total suspended solids (TSS)
Primary and Secondary Titanium
114. antimony
118. cadmium
119. chromium (total)
120. copper
1 22. lead
124. nickel
127. thallium
128. zinc
titanium
fluoride
oil and grease
total suspended solids (TSS)
pH
Secondary Tungsten and Cobalt
1 1 5. arsenic
118. cadmium
119. chromium
120. copper
122. lead
124. nickel
126. silver
128. zinc
cobalt
oil and grease
ammonia (as N)
total suspended solids (TSS)
pH
Secondary Uranium
1 1 5. arsenic
118. cadmium
1 1 9. chromium (total)
120. copper
1 22. lead
124. nickel
204
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125. selenium
128. zinc
uranium
ammonia (as N)
fluoride
total suspended solids (TSS)
PH
Primary Zirconium and Hafnium
118. cadmium
119. chromium (total)
121. cyanide (total)
122. lead
124. nickel
127. thallium
128. zinc
radium 226
ammonia (as N)
total suspended solids (TSS)
pH
205
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Table VI-1
LIST OF 129 TOXIC POLLUTANTS
Compound Name
1. acenaphthene
2. acrolein
3. acrylonitrile
4. benzene
5. benzidene
6. carbon tetrachloride (tetrachloromethane)
Chlorinated benzenes (other than dichlorobenzenes)
7. chlorobenzene
8. 1,2,4-trichlorobenzene
9. hexachlorobenzene
Chlorinated ethanes (including 1,2-dichloroethane,
1,1,1-trichloroethane and hexachloroethane)
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
Chloroalkyl ethers (chloromethyl, chloroethyl and
mixed ethers)
17. bis(chloromethyl) ether (deleted)
18. bis (2-chloroethyl) ether
19. 2-chloroethyl vinyl ether (mixed)
Chlorinated naphthalene
20. 2-chloronaphthalene
Chlorinated phenols (other than those listed elsewhere;
includes trichlorophenols and chlorinated cresols)
21. 2,4,6-trichlorophenol
22. parachlorometa cresol
23. chloroform (trichloromethane)
24. 2-chlorophenol
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Table VI-1 (Continued)
LIST OF 129 TOXIC POLLUTANTS
Dlchlorobenzenes
25. 1,2-dichlorobenzene
26. 1,3-dichlorobenzene
27. 1,4-dichlorobenzene
Dlchlorobenzidine
28. 3,3'-dichlorobenzidine
Dichloroethylenes (1,1-dichloroethylene and
1,2-dichloroethylene)
29. 1,1-dichloroethylene
30. 1,2-trans-dichloroethylene
31. 2,4-dichlorophenol
Dichloropropane and dichloropropene
32. 1,2-dichloropropane
33. 1,2-dichloropropylene (1,3-dichloropropene)
34. 2,4-dimethylphenol
Dinitrotoluene
35. 2,4-dinitrotoluene
36. 2,6-dinitrotoluene
37. 1,2-diphenylhydrazine
38. ethylbenzene
39. fluoranthene
Haloethers (other than those listed elsewhere)
40. 4-chlorophenyl phenyl ether
41. 4-bromophenyl phenyl ether
42. bis (2-chloroisopropyl) ether
43. bis(2-choroethoxy) methane
Halomethanes (other than those listed elsewhere)
44. methylene chloride (dichloromethane)
45. methyl chloride (chloromethane)
46. methyl bromide (bromomethane)
207
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Table VI-1 (Continued)
LIST OF 129 TOXIC POLLUTANTS
Halomethanes (Cont.)
47. bromoform (tribromomethane)
48. dichlorobromomethane
49. trichlorofluoromethane (deleted)
50. dichlorofluoromethane (deleted)
51. chlorodibromomethane
52. hexachlorobutadiene
53. hexachlorocyclopentadiene
54. isophorone
55. naphthalene
56. nitrobenzene
Nitrophenols (including 2,4-dinitrophenol and dinitrocresol)
57. 2-nitrophenol
58. 4-nitrophenol
59. 2,4-dinitrophenol
60. 4,6-dinitro-o-cresol
Nitrosamines
61. N-nitrosodimethylamine
62. N-nitrosodiphenylamine
63. N-nitrosodi-n-propylamine
64. pentachlorophenol
65. phenol
Phthalate esters
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
Polynuclear aromatic hydrocarbons
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)
208
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Table VI-1 (Continued)
LIST OF 129 TOXIC POLLUTANTS
Polynuclear aromatic hydrocarbons (Cont.)
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)
Pesticides and metabolites
89. aldrin
90. dieldrin
91. chlordane (technical mixture and metabolites)
DDT and metabolites
92. 4,4'-DDT
93. 4,4'-DDE(p,p'DDX)
94. 4,4'-DDD(p,p'TDE)
Polychlorinated biphenyls (PCB's)
Endosulfan and metabolites
95. a-endosulfan-Alpha
96. b-endosulfan-Beta
97. endosulfan sulfate
Endrin and metabolites
98. endrin
99. endrin aldehyde
Heptachlor and metabolies
100. heptachlor
101. heptachlor epoxide
209
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Table VI-1 (Continued)
LIST OF 129 TOXIC POLLUTANTS
Hexachlorocyclohexane (all isomers)
102. a-BHC-Alpha
103. b-BHC-Beta
104. r-BHC (lindane)-Gamma
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)
Metals and Cyanide, and Asbestos
114. antimony
115. arsenic
116. asbestos (Fibrous)
117. beryllium
118. cadmium
119. chromium (Total)
120. copper
121. cyanide (Total)
122. lead
123. mercury
124. nickel
125. selenium
126. silver
127. thallium
128. zinc
Other
113. toxaphene
129. 2, 3, 7, 8-tetra chlorodibenzo-p-dioxin (TCDD)
210
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NONFERROUS METALS MANUFACTURING PHASE II
SECTION VII
CONTROL AND TREATMENT TECHNOLOGY
This section describes the treatment techniques currently used or
available to remove or recover wastewater pollutants normally
generated by the nonferrous metals manufacturing industrial point
source category. Included are discussions of individual end-of-
pipe treatment technologies and in-plant technologies. These
treatment technologies are widely used in many industrial
categories, and data and information to support their
effectiveness has been drawn from a similarly wide range of
sources and data bases.
END-OF-PIPE TREATMENT TECHNOLOGIES
Individual recovery and treatment technologies are described
which are used or are suitable for use in treating wastewater
discharges from nonferrous metals manufacturing plants. Each
description includes a functional description and discussion of
application and performance, advantages and limitations,
operational factors (reliability, maintainability, solid waste
aspects), and demonstration status. The treatment processes
described include both technologies presently demonstrated within
the nonferrous metals manufacturing category, and technologies
demonstrated in treatment of similar wastes in other industries.
Nonferrous manufacturing wastewaters characteristically may
contain treatable concentrations of toxic metals. The toxic
metals antimony, arsenic, beryllium, cadmium, copper, lead,
mercury, nickel, selenium, silver thallium and zinc are found in
nonferrous metals manufacturing wastewater streams at treatable
concentrations; and are generally free from strong chelating
agents. Aluminum, ammonia, boron, cyanide, fluoride, germanium,
indium, molybdenum, radium 226, tin, titanium, uranium and some
toxic organics (polynuclear aromatic hydrocarbons and phenols)
also may be present. The toxic inorganic pollutants constitute
the most significant wastewater pollutants in this category.
In general, these pollutants are removed by chemical
precipitation and sedimentation or filtration. Most of them may
be effectively removed by precipitation of metal hydroxides or
carbonates utilizing the reaction with lime, sodium hydroxide, or
sodium carbonate. For some, improved removals are provided by
the use of sodium sulfide or ferrous sulfide to precipitate the
pollutants as sulfide compounds with very low solubilities.
Discussion of end-of-pipe treatment technologies is divided into
three parts: the major technologies; the effectiveness of major
technologies; and minor technologies.
211
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MAJOR TECHNOLOGIES
XII the rationale for selecting
The individual technologies used
hor-e Ths» ma JO*" onH— r\f — ni r»e
metals
i, (2)
filtration, (5) pressure filtration, (6) settling, and (7)
skimming. In practice, precipitation of metals and settling of
the resulting precipitates is often a unified two-step operation.
Suspended solids originally present in raw wastewaters are not
appreciably affected by the orecioitation ©Deration —J
In Sections IX, X
treatment systems is
in the system are
technologies for
wastewaters are: (1)
precipitation, (3)
filtration, (5)
XI, and
described here. The major end-of-pipe
treating nonferrous metals manufacturing
chemical reduction of chromium, (2) chemical
cyanide precipitation, (4) g
»e?e?nv^ ^il^i^a^T/^Fi ( £. \ oo^^li
precipitat
3 H2S03
---- > Cr2(S04)3 + 5 H20
The above reaction is favored by low pH. A pH of from 2 to 3 is
normal for situations requiring complete reduction. At pH levels
above 5, the reduction rate is slow. Oxidizing agents such as
dissolved oxygen and ferric iron interfere with the reduction
process by consuming the reducing agent.
A typical treatment consists of 45 minutes retention in a
reaction tank. The reaction tank has an electronic recorder-
controller device to control process conditions with respect to
pH and oxidation reduction potential (ORP). Gaseous sulfur
dioxide is metered to the reaction tank to maintain the ORP
within the range of 250 to 300 millivolts. Sulfuric acid is
212
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added to maintain a pH level of from 1.8 to 2.0. The reaction
tank is equipped with a propeller agitator designed to provide
approximately one turnover per minute. Figure VII-13 (Page 305)
shows a continuous chromium reduction system.
Application and Performance. Chromium reduction is most usually
required to treat electroplating and metal surfacing rinse
waters, but may also be required in nonferrous metals
manufacturing plants. A study of an operational waste treatment
facility chemically reducing hexavalent chromium has shown that a
99.7 percent reduction efficiency is easily achieved. Final
concentrations of 0.05 mg/1 are readily attained, and
concentrations of 0.01 mg/1 are considered to be attainable by
properly maintained and operated equipment.
Advantages and Limitations. The major advantage of chemical
reduction to reduce hexavalent chromium is that it is a fully
proven technology based on many years of experience. Operation
at ambient conditions results in minimal energy consumption, and
the process, especially when using sulfur dioxide, is well suited
to automatic control. Furthermore, the equipment is readily
obtainable from many suppliers, and operation is straightforward.
One limitation of chemical reduction of hexavalent chromium is
that for high concentrations of chromium, the cost of treatment
chemicals may be prohibitive. When this situation occurs, other
treatment techniques are likely to be more economical. Chemical
interference by oxidizing agents is possible in the treatment 'of
mixed wastes, and the treatment itself may introduce pollutants
if not properly controlled. Storage and handling of sulfur
dioxide is somewhat hazardous.
Operational Factors. Reliability: Maintenance consists of
periodic removal of sludge, the frequency of removal depends on
the input concentrations of detrimental constituents.
Solid Waste Aspects: Pretreatment to eliminate substances which
will interfere with the process may often be necessary. This
process produces trivalent chromium which can be controlled by
further treatment. However, small amounts of sludge may be
collected as the result of minor shifts in the solubility of the
contaminants. This sludge can be processed by the main sludge
treatment equipment.
Demonstration Status. The reduction of chromium waste by sulfur
dioxide or sodium bisulfite"is a classic process and is used by
numerous plants which have hexavalent chromium compounds in
wastewaters from operations such as electroplating, conversion
coating and noncontact cooling.
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2. Chemical Precipitation
Dissolved toxic metal ions and certain anions may be chemically
precipitated for removal by physical means such as sedimentation,
filtration, or centrifugation. Several reagents are commonly
used to effect this precipitation:
1) Alkaline compounds such as lime or sodium hydroxide may be
used to precipitate many toxic metal ions as metal
hydroxides. Lime also may precipitate phosphates as
insoluble calcium phosphate, fluorides as calcium fluoride
and arsenic as calcium arsenate.
2) Both "soluble" sulfides such as hydrogen sulfide or sodium
sulfide and "insoluble" sulfides such as ferrous sulfide may
be used to precipitate many heavy metal ions as metal
sulfides.
3) Ferrous sulfate, zinc sulfate or both (as is required) may
be used to precipitate cyanide as a ferro or zinc
ferricyanide complex.
4) Carbonate precipitates may be used to remove metals either
by direct precipitation using a carbonate reagent such as
calcium carbonate or by converting hydroxides into
carbonates using carbon dioxide.
These treatment chemicals may be added to a flash mixer or rapid
mix tank, to a presettling tank, or directly to a clarifier or
other settling device. Because metal hydroxides tend to be col-
loidal in nature, coagulating agents may also be added to faci-
litate settling. After the solids have been removed, final pH
adjustment may be required to reduce the high pH created by the
alkaline treatment chemicals.
Chemical precipitation as a mechanism for removing metals from
wastewater is a complex process of at least two steps - pre-
cipitation of the unwanted metals and removal of the precipitate.
Some very small amount of metal will remain dissolved in the
wastewater after precipitation is complete. The amount of
residual dissolved metal depends on the treatment chemicals used
and related factors. The effectiveness of this method of
removing any specific metal depends on the fraction of the
specific metal in the raw waste (and hence in the precipitate)
and the effectiveness of suspended solids removal. In specific
instances, a sacrifical ion such as iron or aluminum may be added
to aid in the removal of toxic metals by co-precipitation process
and reduce the fraction of a specific metal in the precipitate.
Application and Performance. Chemical precipitation is used in
nonferrous metals manufacturing for precipitation of dissolved
metals. It can be used to remove metal ions such as aluminum,
antimony, arsenic, beryllium, cadmium, chromium, copper, lead,
214
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mercury, zinc, cobalt, iron, manganese, molybdenum and tin. The
process is also applicable to any substance that can be
transformed into an insoluble form such as fluorides, phosphates,
soaps, sulfides and others. Because it is simple and effective,
chemical precipitation is extensively used for industrial waste
treatment.
The performance of chemical precipitation depends on several
variables. The more important factors affecting precipitation
effectiveness are:
1. Maintenance of an appropriate (usually alkaline) pH
throughout the precipitation reaction and subsequent
settling;
2. Addition of a sufficient excess of treatment ions to
drive the precipitation reaction to completion;
3. Addition of an adequate supply of sacrifical ions (such
as iron or aluminum) to ensure precipitation and
removal of specific target ions; and
4. Effective removal of precipitated solids (see
appropriate solids removal technologies).
Control of pH. Irrespective of the solids removal technology
employed, proper control of pH is absolutely essential for
favorable performance of precipitation-sedimentation
technologies. This is. clearly illustrated by solubility curves
for selected metals hydroxides and sulfides shown in Figure VII-1
(page 318 )/ and by plotting effluent zinc concentrations against
pH as shown in Figure VII-2 (page 319 ). Figure VII-2 was
obtained from Development Document for the Proposed Effluent
Limitations Guidelines and New Source Performance Standards for
the Zinc Segment of_ Nonferrous Metals Manufacturing Point Source
Category, U.S. E.P.A., EPA 440/1-74/033, November, 1974. Figure
VII-2 was plotted from the sampling data from several facilities
with metal finishing operations. It is partially illustrated by
data obtained from 3 consecutive days of sampling at one metal
processing plant (47432) as displayed in Table VII-1 (page 298 ).
Flow through this system is approximately 49,263 1/h (13,000
gal/hr).
This treatment system uses lime precipitation (pH adjustment)
followed by coagulant addition and sedimentation. Samples were
taken before (in) and after (out) the treatment system. The best
treatment for removal of copper and zinc was achieved on day one,
when the pH was maintained at a satisfactory level. The poorest
treatment was found on the second day, when the pH slipped to an
unacceptably low level; intermediate values were achieved on the
third day, when pH values were less than desirable but in between
those for the first and second days.
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Sodium hydroxide is used by one facility (plant 439) for pH
adjustment and chemical precipitation, followed by settling
(sedimentation and a polishing lagoon) of precipitated solids.
Samples were taken prior to caustic addition and following the
polishing lagoon. Flow through the system is approximately
22,700 1/hr. (6,000 gal/hr). These data displayed in Table VII-2
(page 298 ) indicate that the system was operated efficiently.
Effluent pH was controlled within the range of 8.6 to 9.3, and,
while raw waste loadings were not unusually high, most toxic
metals were removed to very low concentrations.
Lime and sodium hydroxide (combined) are sometimes used to
precipitate metals. Data developed from plant 40063, a facility
with a metal bearing wastewater, exemplify efficient operation of
a chemical precipitation and settling system. Table VII-3 (page 299
) shows sampling data from this system, which uses lime and
sodium hydroxide for pH adjustment and chemical precipitation,
polyelectrolyte flocculant addition, and sedimentation. Samples
were taken of the raw waste influent to the system and of the
clarifier effluent. Flow through the system is approximately
19,000 1/hr (5,000 gal/hr).
At this plant, effluent TSS levels were below 15 mg/1 on each
day, despite average raw waste TSS concentrations of over 3500
mg/1. Effluent pH was maintained at approximately 8, lime
addition was sufficient to precipitate the dissolved metal ions,
and the flocculant addition and clarifier retention served to
remove effectively the precipitated solids.
Sulfide precipitation is sometimes used to precipitate metals
resulting in improved metals removals. Most metal sulfides are
less soluble than hydroxides, and the precipitates are frequently
more dependably removed from water. Solubilities for selected
metal hydroxide, carbonate and sulfide precipitates are shown in
Table VII-4, (page 299 ). (Source: Lange's Handbook of
Chemistry). Sulfide precipitation is particularly effective in
removing specific metals such as silver and mercury. Sampling
data from three industrial plants using sulfide precipitation
appear in Table VII-5 (page 300). In all cases except iron,
effluent concentrations are below 0.1 mg/1 and in many cases
below 0.01 mg/1 for the three plants studied.
Sampling data from several chlorine-caustic manufacturing plants
using sulfide precipitation demonstrate effluent mercury
concentrations varying between 0.009 and 0.03 mg/1. As shown in
Figure VII-1, the solubilities of PbS and Ag2S are lower at
alkaline pH levels than either the corresponding hydroxides or
other sulfide compounds. This implies that removal performance
for lead and silver sulfides should be comparable to ot better
than that for the metal hydroxides. Bench scale tests on several
types of metal finishing and manufacturing wastewater indicate
that metals removal to levels of less than 0.05 mg/1 and in some
cases less than 0.01 mg/1 are common in systems using sulfide
216
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precipitation followed by clarification. Some of the bench scale
data, particularly in the case of lead, do not support such low
effluent concentrations. However, lead is consistently removed
to very low levels (less than 0.02 mg/1) in systems using
hydroxide and carbonate precipitation and sedimentation.
Of particular interest is the ability of sulfide to precipitate
hexavalent chromium (Cr+6) without prior reduction to the tri-
valent state as is required in the hydroxide process. When
ferrous sulfide is used as the precipitant, iron and sulfide act
as reducing agents for the hexavalent chromium according to the
reaction:
Cr03+ FeS + 3H20 > Fe(OH)3 + Cr(OH)3 + S
The sludge produced in this reaction consists mainly of ferric
hydroxides, chromic hydroxides, and various metallic sulfides.
Some excess hydroxyl ions are generated in this process, possibly
requiring a downward re-adjustment of pH.
Based on the available data, Table VII-6 (page 301 ) shows the
minimum reliably attainable effluent concentrations for sulfide
precipitation-sedimentation systems. These values are used to
calculate performance predictions of sulfide precipitation-
sedimentation systems.
Sulfide precipitation, is used in many process and wastewater
treatment applications in nonferrous metals manufacturing. This
technology is used to treat process wastewater discharges from
cadmium recovery and to recover metals from zinc baghouse dusts
at a U.S. nonferrous metals manufacturing plant. Another plant
achieves complete recycle of electrolyte from copper refining
through removal of metal impurities via sulfide precipitation.
Primary tungsten is frequently separated from molybdenum via
sulfide precipitation. In secondary tin production, lead is
recovered from alkaline detinning solutions with sulfide
precipitation just prior to electrowinning. In the production of
beryllium hydroxide, sulfide precipitation is used to remove
metal impurities prior to precipitating beryllium hydroxide.
These demonstrations show that sulfide precipitation is in use in
the nonferrous metals manufacturing category that may present
equal or greater treatment difficulties as wastewater.
Sulfide precipitation also is used as a preliminary or polishing
treatment technology for nonferrous metals manufacturing
wastewater. A U.S. nonferrous metals manufacturing facility
specifically uses sulfide precipitation operated at a low pH to
recover specific toxic metals from the acid plant blowdown prior
to discharging the wastewater to a lime and settle treatment
system. Hydrogen sulfide is used to precipitate selenium.
Arsenic is also precipitated as arsenic sulfide. The arsenic and
selenium sulfides are removed in a plate and frame filter. EPA
sampling at this plant found three-day averages of arsenic and
217
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selenium in the untreated acid plant blowdown of 4.74 mg/1 and
21.5 mg/1 of arsenic and selenium, respectively. Composite
samples of treated (sulfide precipitation and filtration) acid
plant blowdown collected during the EPA sampling visit showed
arsenic concentrations at 0.066, 0.348 and 0.472 mg/1. Likewise,
the treated acid plant blowdown samples contained selenium
concentrations at 0.015, 0.05, and 0.132 mg/1.
Performance data collected by personnel at this same plant over a
one year time period (24 data points) indicate the long-term
arithmetic mean for arsenic is 1.2 mg/1. Selenium data gathered
at the same plant over one year (33 data points) show a long-term
arithmetic mean of 0.53 mg/1. The effluent data submitted to the
Agency are quite variable due to the methods used to control
reagent addition by the plant. This is not unexpected since the
plant operates this system for metals recovery and not
necessarily for control of arsenic and selenium discharges. In
fact, there is almost as much variability in the treated effluent
from the filter press as there is in the raw acid plant blowdown.
This is not characteristic of the well-operated treatment systems
where a significant reduction in variability of raw waste loads
is observed. Hydrogen sulfide is added to the acid plant
blowdown based on flow rate, not influent concentration. EPA
sampling data demonstrate that slight increases in influent
arsenic concentration also produce similar increases in effluent
arsenic concentrations. This is characteristic of a system in
which treatment reagents are not being added in sufficient
quantities. The Agency believes more uniform performance would
be achieved if sulfide addition were properly controlled using a
specific ion electrode. This method ofcontrol is demonstrated in
sulfide treatment to recover silver from photographic solutions.
In this way, excess sulfide is consistently added to ensure
proper precipitation of arsenic and selenium sulfides.
While the average for arsenic from this plant is 1.2 mg/1, the
system as operated was able to achieve concentrations as low as
0.04 mg/1. Likewise, for selenium, concentrations as low as 0.01
mg/1 were achieved. The Agency recognizes that it is unlikely
that plants could consistently achieve 0.04 mg/1 and 0.01 mg/1,
respectively; however, this performance indicates that through
proper control of reagent addition the plant would vastly improve
the performance.
Data are also available from a Swedish copper and lead smelter
that operates a full-scale sulfide precipitation and hydroxide
precipitation unit on acid plant blowdown, storm water, and
facility cleaning wastewaters. The full-scale sulfide-hydroxide
precipitation plant was started up in May 1978 and has operated
since that time. The plant personnel compared hydroxide and
sulfide precipitation for removal of toxic metals at the bench
scale prior to design of the full-scale plant. On the basis of
laboratory data, they determined that a combined
sulfide-hydroxide process would be best. This approach resulted
218
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in the best overall removals and yielded a sludge that could be
recycled into the smelting process.
This Swedish plant operates the sulfide precipitation portion of
the process at a pH in the range of 3 to 5 standard' units. This
results in good copper, lead, and zinc removals as well as some
reduction of arsenic and selenium. This mode of operation was
selected to yield a sludge containing copper and lead sulfides
that could be reintroduced readily into the smelter furnaces.
Arsenic concentrations as low as 1.9 mg/1 were achieved even in
this mode which is not optimized for arsenic removal.
There is a Japanese copper smelter with a metallurgical acid
plant that operates a sulfide precipitation and filtration
preliminary treatment system. The plant uses sulfide to treat
acid plant blowdown containing arsenic concentrations of 8,530
mg/1, copper at 120 mg/1, lead at 30 mg/1, copper at 120 mg/1,
lead at 30 mg/1 and cadmium at 60 mg/1. The filtrate from this
treatment system typically contains concentrations of 0.03 mg/1
for arsenic, 0.03 mg/1 for copper, 0.5 mg/1 for lead and 0.3 mg/1
for cadmium. Wastewater from the acid plant is pumped from the
acid plant is pumped to a 50 cubic meter stirred reaction tank
where sodium hydrosulfide is added. Completion of the
precipitation reaction is measured by a oxidation-reduction
potentiometer. After the reaction is complete the wastewater is
pumped to a filter press to separate the precipitated solids from
solution. The filtrate is pumped for additional wastewater
treatment downstream.
EPA and its contractor also conducted bench-scale tests to
determine the effectiveness of sulfide precipitation on
metallurgical acid plant discharges. Wastewater samples were
collected from a U.S. copper smelter and refinery with a
metallurgical acid plant on site. The U.S. plant did not have
raw wastewater arsenic concentrations as high as those of the
Japanese plant; however, the arsenic concentrations from the U.S.
facility have been observed to range from 50-150 mg/1.
Bench-scale tests were conducted using sulfide precipitation and
filtration preliminary treatment in the same way as the
full-scale Japanese plant. At a pH of 1.5 standard units with
excess sodium sulfide, an arsenic concentration of 1.5 mg/1 was
achieved with this preliminary treatment. The fact that the
concentration achieved for arsenic in the bench-scale tests is
higher (1.5 mg/1 as opposed to 0.03 mg/1) than that observed in
the full scale Japanese facility is not unexpected. The purpose
of the bench-scale tests was to demonstrate that effective
removal of arsenic was possible. These operating conditions were
not optimized as they were in the full scale facility. The
bench-scale tests are described in greater detail in a report
entitled, Laboratory Studies on Sulfide Precipitation Applied to
Metallurgical Acid Plant Wastewaters, found in the record
supporting this rulemaking.
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Sulfide precipitation may also be applied following or in
conjunction with hydroxide precipitation (two-stage
treatment-lime followed by sulfide). In these applications
sulfide precipitation acts to further reduce toxic metal
concentrations. Responses to Section 308 data collection
portfolios indicate that there are four nonferrous metals
manufacturing plants using sulfide precipitation as a polishing
step - two primary zinc and two secondary silver plants.
EPA conducted bench-scale tests to examine the effectiveness of
sulfide precipitation used in conjunction with lime precipitation
and following lime and settle treatment. Sulfide precipitation
used in conjunction with lime precipitation applied to wastewater
from a primary zinc process wastewater containing 1.4 mg/1 of
arsenic, 15 mg/1 of cadmium, 7 mg/1 of copper, 5 mg/1 of lead and
114 mg/1 of zinc, achieved effluent concentrations of 0.04 mg/1
of arsenic, 0.05 mg/1 of cadmium, 0.038 mg/1 of copper, 0.027
mg/1 of lead and 0.31 mg/1 of zinc. Sulfide precipitation
applied as a polishing step after lime precipitation achieved
0.04 mg/1 of arsenic, 0.004 mg/1 of cadmium, 0.014 mg/1 of
copper, 0.003 mg/1 of lead and 0.036 mg/1 of zinc when treating
the same process wastewater.
Carbonate precipitation is sometimes used to precipitate metals,
especially where precipitated metals values are to be recovered.
The solubility of most metal carbonates is intermediate between
hydroxide and sulfide solubilities; in addition, carbonates form
easily filtered precipitates. Carbonate ions appear to be
particularly useful in precipitating lead and antimony. Sodium
carbonate has been observed being added at treatment to improve
lead precipitation and removal in some industrial plants. The
lead hydroxide and lead carbonate solubility curves displayed in
Figure VII-3 (page 299 ) (Source: "Heavy Metals Removal," by
Kenneth Lanovette, Chemical Enqineerinq/Deskbook Issue, October
17, 1977) explain this phenomenon.
Co-precipitation With Iron. The presence of substantial
quantites of iron in metal bearing wastewaters before treatment
has been shown to improve the removal of toxic metals. In some
cases this iron is an integral part of the industrial wastewater;
in other cases iron is deliberately added as a preliminary
treatment or first step of treatment. The iron functions to
improve toxic metal removal by three mechanisms: the iron co-
precipitates with toxic metals forming a stable precipitate which
desolubilizes the toxic metal; the iron improves the
settleability of the precipitate; and the large amount of iron
reduces the fraction of toxic metal in the precipitate. Co-
precipitation with iron has been practiced for many years
incidentally when iron was a substantial consitutent of raw
wastewater and intentionally when iron salts were added as a
coagulant aid. Aluminum or mixed iron-aluminum salt also have
been used.
220
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Co-precipitation using large amounts of ferrous iron salts is
known as ferrite co-precipitation because magnetic iron oxide or
ferrite is formed. The addition of ferrous salts (sulfate) is
followed by alkali precipitation and air oxidation. The
resultant precipitate is easily removed by filtration and may be
removed magnetically. Data illustrating the performance of
ferrite co-precipitation is shown in Table VII-7, (page 302 )•
Advantages and Limitations. Chemical precipitation has proved to
be an effective technique for removing many pollutants from
industrial wastewater. It operates at ambient conditions and is
well suited to automatic control. The use of chemical
precipitation may be limited because of interference by chelating
agents, because of possible chemical interference with mixed
wastewaters and treatment chemicals, or because of the
potentially hazardous situation involved with the storage and
handling of those chemicals. Nonferrous manufacturing
wastewaters do not normally contain chelating agents or complex
pollutant matrix formations which would interfere with or limit
the use of chemical precipitation. Lime is usually added as a
slurry when used in hydroxide precipitation. The slurry must be
kept well mixed and the addition lines periodically checked to
prevent blocking of the lines, which may result from a buildup of
solids. Also, lime precipitation usually makes recovery of the
precipitated metals difficult, because of the heterogeneous
nature of most lime sludges.
The major advantage of the sulfide precipitation process is that
the extremely low solubility of most metal sulfides promotes very
high metal removal*efficiencies; the sulfide process also has the
ability to remove chromates and dichromates without preliminary
reduction of the chromium to its trivalent state. In addition,
sulfide can precipitate metals complexed with most complexing
agents. The process demands care, however, in maintaining the pH
of the solution at approximately 10 in order to restrict the gen-
eration of toxic hydrogen sulfide gas. For this reason,
ventilation of the treatment tanks may be a necessary precaution
in most installations. The use of insoluble sulfides reduces the
problem of hydrogen sulfide evolution. As with hydroxide
precipitation, excess sulfide ion must be present to drive the
precipitation reaction to completion. Since the sulfide ion
itself is toxic, sulfide addition must be carefully controlled to
maximize heavy metals precipitation with a minimum of excess
sulfide to avoid the necessity of additional wastewater
treatment. At very high excess sulfide levels and high pH,
soluble mercury-sulfide compounds may also be formed. Where
excess sulfide is present, aeration of the effluent stream can
aid in oxidizing residual sulfide to the less harmful sodium
sulfate (Na2S04). The cost of sulfide precipitants is high in
comparison to hydroxide precipitants, and disposal of metallic
sulfide sludges may pose problems. An essential element in
effective sulfide precipitation is the removal of precipitated
solids from the wastewater and proper disposal in an appropriate
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site. Sulfide precipitation will also generate a higher volume
of sludge than hydroxide precipitation, resulting in higher
disposal and dewatering costs. This is especially true when
ferrous sulfide is used as the precipitant.
Sulfide precipitation may be used as a polishing treatment after
hydroxide precipitation-sedimentation. This treatment
configuration may provide the better treatment effectiveness of
sulfide precipitation while minimizing the variability caused by
changes in raw waste and reducing the amount of sulfide
precipitant required.
Operational Factors. Reliability: Alkaline chemical
precipitation is highly reliable, although proper monitoring and
control are required. Sulfide precipitation systems provide
similar reliability.
Maintainability: The major maintenance needs involve periodic
upkeep of monitoring equipment, automatic feeding equipment,
mixing equipment, and other hardware. Removal of accumulated
sludge is necessary for efficient operation of precipitation-
sedimentation systems.
Solid Waste Aspects: Solids which precipitate out are removed in
a subsequent treatment step. Ultimately, these solids require
proper disposal.
Demonstration Status. Chemical precipitation of metal hydroxides
is a classic waste treatment technology used by most industrial
waste treatment systems. Chemical precipitation of metals in the
carbonate form alone has been found to be feasible and is
commercially used to permit metals recovery and water reuse.
Full scale commercial sulfide precipitation units are in
operation at numerous installations, including several plants in
the nonferrous metals manufacturing category. As noted earlier,
sedimentation to remove precipitates is discussed separately.
Use jjn Nonferrous Metals Manufacturing Plants. Hydroxide
chemical precipitation is used at 121 nonferrous metals
manufacturing plants. Sulfide precipitation is used in four
nonferrous metals manufacturing plants.
3. Cyanide Precipitation
Cyanide precipitation, although a method for treating cyanide in
wastewaters, does not destroy cyanide. The cyanide is retained
in the sludge that is formed. Reports indicate that during
exposure to sunlight, the ryanide complexes can break down and
form free cyanide. For this reason, the sludge from this
treatment method must be disposed of carefully.
Cyanide may be precipitated and settled out of wastewaters by the
addition of zinc sulfate or ferrous sulfate. In the presence of
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iron, cyanide will form extremely stable cyanide complexes. The
addition of zinc sulfate or ferrous sulfate forms zinc
ferrocyanide or ferro ferricyanide complexes.
Cyanide precipitation occurs in two steps: reaction with ferrous
sulfate or zinc sulfate at an alkaline pH to form iron or zinc
cyanide complexes followed by reaction at a low pH with
additional ferrous sulfate or ferric chloride to form insoluble
iron cyanide precipitates. Cyanide precipitation is applicable
to all cyanide-containing wastewater and, unlike many oxidation
technologies, is not limited by the presence of complexed
cyanides. The oxidation technologies discussed later in this
section are applicable for waste streams containing only
uncomplexed cyanides. Cyanide precipitation has been selected as
the technology basis for cyanide control because of the presence
of iron, nickel, and zinc in wastewaters in this category. These
toxic metals are known to form stable complexes with cyanide.
Cyanide-containing wastewater is introduced into a mixing chamber
where ferrous sulfate (as the heptahydrate (FeS04 . 7H20)), is
added to form a hexacyanoferrate complex. The hexacyanoferrate
complex is most stable at a ph of 9 (standard units). Thus, the
complexation reaction is performed at pH 9. The amount or dosage
of ferrous sulfate is dependent upon the chemical form of the
cyanide in the wastewater. Cyanide may be present in one of two
forms, free or complexed (sometimes referred to as fixed).
Various analytical methods to determine the portions of free and
complexed cyanides in wastewater have been presented in the
literature (2, 3, 4). Free cyanide, which refers to the portion
of total cyanide that freely dissociates in water (e.g., HCN),
reacts with the ferrous sulfate to form the complex, according
to:
FeS04 + 6CN- - > Fe(CN)64~ + S042~ (complexation reaction)
Complexed cyanide, present as the hexacyanoferrate or
metallocyanide complexes, is already in the desired chemical
form. In theory, the ferrous sulfate dosage is determined by
calculating the stoichiometric equivalent required for the free
cyanide present, that is, one mole of ferrous sulfate per six
moles of cyanide. In actual practice, the dosage requirements
are greater than the stoichiometric equivalent (5, 6). One
reason that excess ferrous sulfate is required is that the
complexation reaction is very slow and the excess of reactants
increases the reaction rate. Another reason is that in treatment
systems, where lime or other sources of hydroxide ions are added
to raise the pH to 8, some of the lime will react with the
ferrous sulfate to form calcium sulfate.
After forming the complex, the wastewater is then mixed with
ferric chloride or additional ferrous sulfate and the pH adjusted
using acid (e.g., H2S04) in the range of 2 to 4. The ferric
chloride or ferrous sulfate reacts with the hexacyanoferrate to
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form ferrihexacyanoferrate or ferrohexacyanoferrate,
respectively, according to:
4FeCl3 + 3Fe(CN6) *- -> Fe4(Fe(CN)6) 3
2FeS04 + Fe(CN)6«- -> (Fe2(Fe(CN)t)
The wastewater is then introduced into a clarifier to allow these
insoluble precipitates to settle. Sedimentation (settling) is
discussed in a later subsection.
Adequate complexation of cyanide requires that the pH must be
kept at 9.0 and an appropriate retention time be maintained. A
study has shown that the formation of the complex is very
dependent on pH. At a pH of either 8 or 10, the residual cyanide
concentrations measured are twice that of the same reaction
carried out at a pH of 9. Removal ef-ficiencies also depend
heavily on the retention time allowed. The formation of the
complexes takes place rather slowly. Depending upon the excess
amount of zinc sulfate or ferrous sulfate added, at least a 30
minute retention time should be allowed for the formation of the
cyanide complex before continuing on to the clarification stage.
One experiment with an initial concentration of 10 mg/1 of
cyanide showed that 98 percent of the cyanide was complexed ten
minutes after the addition of ferrous sulfate at twice the
theoretical amount necessary. Interference from other metal
ions, such as cadmium, might result in ttie need for longer
retention times.
Table VII-8 (page 302 ) presents cyanide precipitation data from
three coil coating plants. A fourth plant was visited for the
purpose of observing plant testing of the cyanide precipitation
system. Specific data from this facility are not included
because: (1) the pH was usually well below the optimum level of
9.0; (2) the historical treatment data were not obtained using
the standard cyanide analysis procedure; and (3) matched input-
output data were not made available by the plant. Scanning the
available data indicates that the raw waste CN level was in the
range of 25.0; the pH 7.5; and treated CN level was from 0.1 to
0.2.
The concentrations are those of the stream entering and leaving
the treatment system. Plant 1057 allowed a 27-minute retention
time for the formation of the complex. The retention time for
the other plants is not known. The data suggest that over a wide
range of cyanide concentration in the raw waste, the
concentration of cyanide can be reduced in the effluent stream to
under 0.15 mg/1.
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Application and Performance. Cyanide precipitation can be used
when cyanide destruction is not feasible because of the presence
of cyanide complexes which are difficult to destroy. Effluent
concentrations of cyanide well below 0.15 mg/1 are possible.
Advantages and Limitations. Cyanide precipitation is an
inexpensive method of treating cyanide. Problems may occur when
metal ions interfere with the formation of the complexes.
4. Granular Bed Filtration
Filtration occurs in nature as the surface ground waters are
cleansed by sand. Silica sand, anthracite coal, and garnet are
common filter media used in water treatment plants. These are
usually supported by gravel. The media may be used singly or in
combination. The multi-media filters may be arranged to maintain
relatively distinct layers by virtue of balancing the forces of
gravity, flow, and buoyancy on the individual particles. This is
accomplished by selecting appropriate filter flow rates (gpm/sq-
ft), media grain size, and density.
Granular bed filters may be classified in terms of filtration
rate, filter media, flow pattern, or method of pressurization.
Traditional rate classifications are slow sand, rapid sand, and
high rate mixed media. In the slow sand filter, flux or
hydraulic loading is relatively low, and removal of collected
solids to clean the filter is therefore relatively infrequent.
The filter is often cleaned by scraping off the inlet face (top)
of the sand bed. In the higher rate filters, cleaning is
frequent and is accomplished by a periodic backwash, opposite to
the direction of normal flow.
A filter may use a single medium such as sand or diatomaceous
earth, but dual and mixed (multiple) media filters allow higher
flow rates and efficiencies. The dual media filter usually
consists of a fine bed of sand under a coarser bed of anthracite
coal. The coarse coal removes most of the influent solids, while
the fine sand performs a polishing function. At the end of the
backwash, the fine sand settles to the bottom because it is
denser than the coal, and the filter is ready for normal
operation. The mixed media filter operates on the same
principle, with the finer, denser media at the bottom and the
coarser, less dense media at the top. The usual arrangement is
garnet at the bottom (outlet end) of the bed, sand in the middle,
and anthracite coal at the top. Some mixing of these layers
occurs and is, in fact, desirable.
The flow pattern is usually top-to-bottom, but other patterns are
sometimes used. Upflow filters are sometimes used, and in a
horizontal filter the flow is horizontal. In a biflow filter,
the influent enters both the top and the bottom and exits
laterally. The advantage of an upflow filter is that with an
upflow backwash, the particles of a single filter medium are
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distributed and maintained in the desired coarse-to-fine (bottom-
to- top) arrangement. The disadvantage is that the bed tends to
become fluidized, which ruins filtration efficiency. The biflow
design is an attempt to overcome this problem.
The classic granular bed filter operates by gravity flow;
however, pressure filters are fairly widely used. They permit
higher solids loadings before cleaning and are advantageous when
the filter effluent must be pressurized for further downstream
treatment. In addition, pressure filter systems are often less
costly for low to moderate flow rates.
Figure VII-14 (page 305 ) depicts a high rate, dual media, gravity
downflow granular bed filter, with self-stored backwash. Both
filtrate and backwash are piped around the bed in an arrangement
that permits gravity upflow of the backwash, with the stored
filtrate serving as backwash. Addition of the indicated
coagulant and polyelectrolyte usually results in a substantial
improvement in filter performance.
Auxilliary filter cleaning is sometimes employed in the upper few
inches of filter beds. This is conventionally referred to as
surface wash and is accomplished by water jets just below the
surface of the expanded bed during the backwash cycle. These
jets enhance the scouring action in the bed by increasing the
agitation.
An important feature for successful filtration and backwashing is
the underdrain. This is the support structure for the bed. The
underdrain provides an area for collection of the fil'tered water
without clogging from either the filtered solids or the media
grains. In addition, the underdrain prevents loss of the media
with the water, and during the backwash cycle it provides even
flow distribution over the bed. Failure to dissipate the
velocity head during the filter or backwash cycle will result in
bed upset and the need for major repairs.
Several standard approaches are employed for filter underdrains.
The simplest one consists of a parallel porous pipe imbedded
under a layer of coarse gravel and manifolded to a header pipe
for effluent removal. Other approaches to the underdrain system
are known as the Leopold and Wheeler filter bottoms. Both of
these incorporate false concrete bottoms with specific porosity
configurations to provide drainage and velocity head dissipation.
Filter system operation may be manual or automatic. The filter
backwash cycle may be on a timed basis, a pressure drop basis
with a terminal value which triggers backwash, or a solids carry-
over basis from turbidity monitoring of the outlet stream. All
of these schemes have been used successfully.
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Application and Performance. Wastewater treatment plants often
use granular bed filters for polishing after clarification,
sedimentation, or other similar operations. Granular bed
filtration thus has potential application to nearly all
industrial plants. Chemical additives which enhance the upstream
treatment equipment may or may not be compatible with or enhance
the filtration process. Normal operating flow rates for various
types of filters are:
Slow Sand 2.04 - 5.30 1/sq m-hr
Rapid Sand 40.74 - 51.48 1/sq m-hr
High Rate Mixed Media 81.48 - 122.22 1/sq m-hr
Suspended solids are commonly removed from wastewater streams by
filtering through a deep 0.3-0.9 m (1-3 feet) granular filter
bed. The porous bed formed by the granular media can be designed
to remove practically all suspended particles. Even colloidal
suspensions (roughly 1 to 100 microns) are adsorbed on the
surface of the media grains as they pass in close proximity in
the narrow bed passages.
Properly operated filters following some pretreatment to reduce
suspended solids below 200 mg/1 should produce water with less
than 10 mg/1 TSS. For example, multimedia filters produced the
effluent qualities shown in Table VII-9 (page 303 ).
Advantages and Limitations.' The principal advantages of granular
bed filtration are its comparatively (to other filters) low
initial and operating costs, reduced land requirements over other
methods to achieve the same level of solids removal, and
elimination of chemical additions to the discharge stream.
However, the filter may require pretreatment if the solids level
is high (over 100 mg/1). Operator training must be somewhat
extensive due to the controls and periodic backwashing involved,
and backwash must be stored and dewatered for economical
disposal.
Operational Factors. Reliability: The recent improvements in
filter technology have significantly improved filtration
reliability. Control systems, improved designs, and good
operating procedures have made filtration a highly reliable
method of water treatment.
Maintainability: Deep bed filters may be operated with either
manual or automatic backwash. In either case, they must be
periodically inspected for media attrition, partial plugging, and
leakage. Where backwashing is not used, collected solids must be
removed by shoveling, and filter media must be at least partially
replaced.
Solid Waste Aspects: Filter backwash is generally recycled
within the wastewater treatment system, so that the solids
ultimately appear in the clarifier sludge stream for subsequent
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dewatering. Alternatively, the backwash stream may be dewatered
directly or, if there is no backwash, the collected solids may be
disposed of in a suitable landfill. In either of these
situations there is a solids disposal problem similar to that of
clarifiers.
Demonstration Status. Deep bed filters are in common use in
municipal treatment plants. Their use in polishing industrial
clarifier effluent is increasing, and the technology is proven
and conventional. Granular bed filtration is used in 25
nonferrous metals manufacturing plants. As noted previously,
however, little data is available characterizing the
effectiveness of filters presently in use within the industry.
5. Pressure Filtration
Pressure filtration works by pumping the liquid through a filter
material which is impenetrable to the solid phase. The positive
pressure exerted by the feed pumps or other mechanical means
provides the pressure differential which is the principal driving
force. Figure VII-15 (page 306) represents the operation of one
type of pressure filter.
A typical pressure filtration unit consists of a number of plates
or trays which are held rigidly in a frame to ensure alignment
and which are pressed together between a fixed end and a
traveling end. On the surface of each plate, a filter made of
cloth or synthetic fiber is mounted. The feed stream is pumped
into the unit and passes through holes in the trays along the
length of the press until the cavities or chambers between the
trays are completely filled. The solids are then entrapped, and
a cake begins to form on the surface of the filter material. The
water passes through the fibers, and the solids are retained.
At the bottom of the trays are drainage ports. The filtrate is
collected and discharged to a common drain. As the filter medium
becomes coated with sludge, the flow of filtrate through the
filter drops sharply, indicating that the capacity of the filter
has been exhausted. The unit must then be cleaned of the sludge.
After the cleaning or replacement of the filter media, the unit
is again ready for operation.
Application and Performance. Pressure filtration is used in
nonferrous metals manufacturing for sludge dewatering and also
for direct removal of precipitated and other suspended solids
from wastewater. Because dewatering is such a common operation
in treatment systems, pressure filtration is a technique which
can be found in many industries concerned with removing solids
from their waste stream.
In a typical pressure filter, chemically preconditioned sludge
detained in the unit for one to three hours under pressures
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varying from 5 to 13 atmospheres exhibited final solids content
between 25 and 50 percent.
Advantages and Limitations. The pressures which may be applied
to a sludge for removal of water by filter presses that are
currently available range from 5 to 13 atmospheres. As a result,
pressure filtration may reduce the amount of chemical
pretreatment required for sludge dewatering. Sludge retained in
the form of the filter cake has a higher percentage of solids
than that from centrifuge or vacuum filter. Thus, it can be
easily accommodated by materials handling systems.
As a primary solids removal technique, pressure filtration
requires less space than clarification and is well suited to
streams with high solids loadings. The sludge produced may be
disposed without further dewatering, but the amount of sludge is
increased by the use of filter precoat materials (usually
diatomaceous earth). Also, cloth pressure filters often do not
achieve as high a degree of effluent clarification as clarifiers
or granular media filters.
Two disadvantages associated with pressure filtration in the past
have been the short life of the filter cloths and lack of
automation. New synthetic fibers have largely offset the first
of these problems. Also, units with automatic feeding and
pressing cycles are now available.
For larger operations, the relatively high space requirements, as
compared to those of a centrifuge, could be prohibitive in some
situations.
Operational Factors. Reliability: With proper pretreatment,
design, and control, pressure filtration is a highly dependable
system.
Maintainability: Maintenance consists of periodic cleaning or
replacement of the filter media, drainage grids, drainage piping,
filter pans, and other parts of the system. If the removal of
the sludge cake is not automated, additional time is required for
this operation.
Solid Waste Aspects: Because it is generally drier than other
types of sludges, the filter sludge cake can be handled with
relative ease. The accumulated sludge may be disposed by any of
the accepted procedures depending on its chemical composition.
The levels of toxic metals present in sludge from treating
battery wastewater necessitate proper disposal.
Demonstration Status. Pressure filtration is a commonly used
technology in a great many commercial applications.
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6. Settling
Settling is a process which removes solid particles from a liquid
matrix by gravitational force. This is done by reducing the
velocity of the feed stream in a large volume tank or lagoon so
that gravitational settling can occur. Figure VII-16 (page 306 )
shows two typical settling devices.
Settling is often preceded by chemical precipitation which
converts dissolved pollutants to solid form and by coagulation
which enhances settling by coagulating suspended precipitates
into larger, faster settling particles.
If no chemical pretreatment is used, the wastewater is fed into a
tank or lagoon where it loses velocity and the suspended solids
are allowed to settle out. Long retention times are generally
required. Accumulated sludge can be collected either
periodically or continuously and either manually or mechanically.
Simple settling, however, may require excessively large
catchments, and long retention times (days as compared with
hours) to achieve high removal efficiencies. Because of this,
addition of settling aids such as alum or polymeric flocculants
is often economically attractive.
In practice, chemical precipitation often precedes settling, and
inorganic coagulants or polyelectrolytic flocculants are usually
added as well. Common coagulants include sodium sulfate, sodium
aluminate, ferrous or ferric sulfate, and ferric chloride.
Organic polyelectrolytes vary in structure, but all usually form
larger floe particles than coagulants used alone.
Following this pretreatment, the wastewater can be fed into a
holding tank or lagoon for settling, but is more often piped into
a clarifier for the same purpose. A clarifier reduces space
requirements, reduces retention time, and increases solids
removal efficiency. Conventional clarifiers generally consist of
a circular or rectangular tank with a mechanical sludge
collecting device or with a sloping funnel-shaped bottom designed
for sludge collection. In advanced settling devices, inclined
plates, slanted tubes, or a lamellar network may be included
within the clarifier tank in order to increase the effective
settling area, increasing capacity. A fraction of the sludge
stream is often recirculated to the inlet, promoting formation of
a denser sludge.
Settling is based on the ability of gravity (Newton's Law) to
cause small particles to fall or settle (Stokes1 Law) through the
fluid they are suspended in. Presuming that the factors
affecting chemical precipitation are controlled to achieve a
readily settleable precipitate, the principal factors controlling
settling are the particle characteristics and the upflow rate of
the suspending fluid. When the effective settling area is great
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enough to allow settling, any increase in the effective settling
area will produce no increase in solids removal.
Therefore, if a plant has installed equipment that provides the
appropriate overflow rate, the precipitated solids (including
toxic metals) in the effluent can be effectively removed. The
number of settling devices operated in series or in parallel by a
facility is not important with regard to suspended solids
removal. Rather, it is important that the settling devices
provide sufficient effective settling area.
Another important facet of sedimentation theory is that
diminishing removal of suspended solids is achieved for a unit
increase in the effective settling area. Generally, it has been
found that suspended solids removal performance varies with the
effective up-flow rate. Qualitatively the performance increases
asymptotically to a maximum level beyond which a decrease in up-
flow rate provides incrementally insignificant increases in
removal. This maximum level is dictated by particle size
distribution, density characteristic of the particles and the
water matrix, chemicals used for precipitation and pH at which
precipitation occurs.
Application and Performance. Settling and clarification are used
in the nonferrous metals manufacturing category to remove
precipitated metals. Settling can be used to remove most
suspended solids in a particular waste stream; thus it is used
extensively by many different industrial waste treatment
facilities. Because most metal ion pollutants are readily
converted to solid metal hydroxide precipitates, settling is of
particular use in those industries associated with metal
production, metal finishing, metal working, and any other
industry with high concentrations of metal ions in their
wastewaters. In addition to toxic metals, suitably precipitated
materials effectively removed by settling include aluminum, iron,
manganese, cobalt, antimony, beryllium, molybdenum, fluoride,
phosphate, and many others.
A properly operating settling system can efficiently remove
suspended solids, precipitated metal hydroxides, and other
impurities from wastewater. The performance of the process
depends on a variety of factors, including the density and
particle size of the solids, the effective charge on the
suspended particles, and the types of chemicals used in
pretreatment. The site of flocculant -or coagulant addition also
may significantly influence the effectiveness of clarification.
If the flocculant is subjected to too much mixing before entering
the clarifier, the complexes may be sheared and the settling
effectiveness diminished. At the same liir.e, the flocculant must
have sufficient mixing and reaction time in order for effective
set-up and settling to occur. Plant personnel have observed that
the line or trough leading into the clarifier is often the most
efficient site for flocculant addition. The performance of
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simple settling is a function of the movement rate particle size
and density, and the surface area of the basin.
The data displayed in Table VII-10 (page 303 ) indicate suspended
solids removal efficiencies in settling systems.
The mean effluent TSS concentration obtained by the plants shown
in Table VII-10 is 10.1 mg/1. Influent concentrations averaged
838 mg/1. The maximum effluent TSS value reported is 23 mg/1.
These plants all use alkaline pH adjustment to precipitate metal
hydroxides, and most add a coagulant or flocculant prior to
settling.
Advantages and Limitations. The major advantage of simple
settling is its simplicity as demonstrated by the gravitational
settling of solid particulate waste in a holding tank or lagoon.
The major problem with simple settling is the long retention time
necessary to achieve complete settling, especially if the
specific gravity of the suspended matter is close to that of
water. Some materials cannot be practically removed by simple
settling alone.
Settling performed in a clarifier is effective in removing slow-
settling suspended matter in a shorter time and in less space
than a simple settling system. Also, effluent quality is often
better from a clarifier. The cost of installing and maintaining
a clarifier, however, is substantially greater than the costs
associated with simple settling.
Inclined plate, slant tube, and lamella settlers have even higher
removal efficiencies than conventional clarifiers, and greater
capacities per unit area are possible. Installed costs for these
advanced clarification systems are claimed to be one half the
cost of conventional systems of similar capacity.
Operational Factors. Reliability: Settling can be a highly
reliable technology for removing suspended solids. Sufficient
retention time and regular sludge removal are important factors
affecting the reliability of all settling systems. Proper
control of pH adjustment, chemical precipitation, and coagulant
or flocculant addition are additional factors affecting settling
efficiencies in systems (frequently clarifiers) where these
methods are used.
Those advanced settlers using slanted tubes, inclined plates, or
a lamellar network may require pre-screening of the waste in
order to eliminate any fibrous materials which could potentially
clog the system. Some installations are especially vulnerable to
shock loadings, as from storm water runoff, but proper system
design will prevent this.
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Maintainability: When clarifiers or other advanced settling
devices are used, the associated system utilized for chemical
pretreatment and sludge dragout must be maintained on a regular
basis. Routine maintenance of mechanical parts is also
necessary. Lagoons require little maintenance other than
periodic sludge removal.
Demonstration Status. Settling represents the typical method of
solids removal and is employed extensively in industrial waste
treatment. The advanced clarifiers are just beginning to appear
in significant numbers in commercial applications.
7. Skimming
Pollutants with a specific gravity less than water will often
float unassisted to the surface of the wastewater. Skimming
removes these floating wastes. Skimming normally takes place in
a tank designed to allow the floating debris to rise and remain
on the surface, while the liquid flows to an outlet located below
the floating layer. Skimming devices are therefore suited to the
removal of non-emulsified oils from raw waste streams. Common
skimming mechanisms include the rotating drum type, which picks
up oil from the surface of the water as it rotates. A doctor
blade scrapes oil from the drum and collects it in a trough for
disposal or reuse. The water portion is allowed to flow under
the rotating drum. Occasionally, an underflow baffle is
installed after the drum/ this has the advantage of retaining any
floating oil which escapes the drum skimmer. The belt type
skimmer is pulled vertically through the water, collecting oil
which is scraped off from the surface and collected in a drum.
Gravity separators, such as the API type, utilize overflow and
underflow baffles to skim a floating oil layer from the surface
of the wastewater. An overflow-underflow baffle allows a small
amount of wastewater (the oil portion) to flow over into a trough
for disposition or reuse while the majority of the water flows
underneath the baffle. This is followed by an overflow baffle,
which is set at a height relative to the first baffle such that
only the oil bearing portion will flow over the first baffle
during normal plant operation. A diffusion device, such as a
vertical slot baffle, aids in creating a uniform flow through the
system and in increasing oil removal efficiency.
Application and Performance. Oil skimming is used in nonferrous
metals manufacturing to remove free oil and grease used as
lubricants in some types of metal casting. Another source of oil
is lubricants for drive mechanisms and other machinery contacted
by process water. Skimming is applicable to any waste stream
containing pollutants which float to the surface. It is commonly
used to remove free oil, grease, and soaps. Skimming is oft*»n
used in conjunction with air flotation or clarification in order
to increase its effectiveness.
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The removal efficiency of a skimmer is partly a function of the
retention time of the water in the tank. Larger, more buoyant
particles require less retention time than smaller particles.
Thus, the efficiency also depends on the composition of the waste
stream. The retention time required to allow phase separation
and subsequent skimming varies from 1 to 15 minutes, depending on
the wastewater characteristics.
API or other gravity-type separators tend to be more suitable for
use where the amount of surface oil flowing through the system is
consistently significant. Drum and belt type skimmers are
applicable to waste streams which evidence smaller amounts of
floating oil and where surges of floating oil are not a problem.
Using an API separator system in conjunction with a drum type
skimmer would be a very effective method of removing floating
contaminants from non-emulsified oily waste streams. Sampling
data shown in Table VII-U (page 304) illustrate the capabilities
of the technology with both extremely high and moderate oil
influent levels.
These data are intended to be illustrative of the very high level
of oil and grease removals attainable in a simple two-step oil
removal system. Based on the performance of installations in a
variety of manufacturing plants and permit requirements that are
consistently achieved, it is determined that effluent oil levels
may be reliably reduced below 10 mg/1 with moderate influent
concentrations. Very high concentrations of oil such as the 22
percent shown above may require two step treatment to achieve
this level.
Skimming which removes oil may also be used to remove base levels
of organics. Plant sampling data show that many organic
compounds tend to be removed in standard wastewater treatment
equipment. Oil separation not only removes oil but also organics
that are more soluble in oil than in water. Clarification
removes organic solids directly and probably removes dissolved
organics by adsorption on inorganic solids.
The source of these organic pollutants is not always known with
certainty, although in metal forming operations they seem to
derive mainly from various process lubricants. They are also
sometimes present in the plant water supply, as additives to
proprietary formulations of cleaners, or as the result of
leaching from plastic lines and other materials.
High molecular weight organics in particular are much more
soluble in organic solvents than in water. Thus they are much
more concentrated in the oil phase that is skimmed than in the
wastewater. The ratio of solubilities of a compound in oil and
water phases is called the partition coefficient. The logarithm
of the partition coefficients for selected polynuclear aromatic
hydrocarbon (PAH) and other toxic organic compounds in octanol
and water are shown in Table VII-12 (page 304).
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A review of priority organic compounds commonly found in metal
forming operation waste streams indicated that incidental removal
of these compounds often occurs as a result of oil removal or
clarification processes. When all organics analyses from visited
plants are considered, removal of organic compounds by other
waste treatment technologies appears to be marginal in many
cases. However, when only raw waste concentrations of 0.05 mg/1
or greater are considered, incidental organics removal becomes
much more apparent. Lower values, those less than 0.05 mg/1, are
much more subject to analytical variation, while higher values
indicate a significant presence of a given compound. When these
factors are taken into account, analysis data indicate that most
clarification and oil removal treatment systems remove
significant amounts of the toxic organic compounds present in the
raw waste. The API oil-water separation system performed notably
in this regard, as shown in Table VII-13 (page 305 ).
Data from five plant days demonstrate removal of organics by the
combined oil skimming and settling operations performed on coil
coating wastewaters. Days were chosen where treatment system
influent and effluent analyses provided paired data points for
oil and grease and the organics present. All organics found at
quantifiable levels on those days were included. Further, only
those days were chosen where oil and grease raw wastewater
concentrations exceeded 10 mg/1 and where there was reduction in
oil and grease going through the treatment system. All plant
sampling days which met the above criteria are included below.
The conclusion is that when oil and grease are removed, organics
also are removed.
Percent Removal
Plant-Day Oil & Grease Organics
1054-3
13029-2
13029-3
38053-1
38053-2
Mean
The unit operation most applicable to removal of trace priority
organics is adsorption, and chemical oxidation is another
possibility. Biological degradation is not generally applicable
because the organics are not present in sufficient concentration
to sustain a biomass and because most of the organics are
resistant to biodegradation.
Advantages and Limitations. Skimming as a pretreatment is
effective in removing naturally floating waste material. It also
improves the performance of subsequent downstream treatments.
Many pollutants, particularly dispersed or emulsified oil, will
not float "naturally" but require additional treatments. There-
fore, skimming alone may not remove all the pollutants capable of
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being removed by air flotation or other more sophisticated
technologies.
Operational Factors. Reliability: Because of its simplicity,
skimming is a very reliable technique.
Maintainability: The skimming mechanism requires periodic
lubrication, adjustment, and replacement of worn parts.
Solid Waste Aspects: The collected layer of debris must be
disposed of by contractor removal, landfill, or incineration.
Because relatively large quantities of water are present in the
collected wastes, incineration is not always a viable disposal
method.
Demonstration Status. Skimming is a common operation utilized
extensively by industrial waste treatment systems. Oil skimming
is used in four nonferrous metals manufacturing plants.
MAJOR TECHNOLOGY EFFECTIVENESS
The performance of individual treatment technologies was
presented above. Performance of operating systems is discussed
here. Two different systems are considered: L&S (hydroxide
precipitation and sedimentation or lime and settle) and LS&F
(hydroxide precipitation, sedimentation, and filtration or lime,
settle, and filter). Subsequently, an analysis of effectiveness
of such systems is made to develop one-day maximum, and ten-day
and thirty-day average concentration levels to be used in
regulating pollutants. Evaluation of the L&S and the LS&F
systems is carried out on the assumption that chemical reduction
of chromium, cyanide precipitation and oil removal are installed
and operating properly where appropriate.
L&S Performance — Combined Metals Data Base
A data base known as the "combined metals data base" (CMDB) was
used to determine treatment effectiveness of lime and settle
treatment for certain pollutants. The CMDB was developed over
several years and has been used in a number of regulations.
During the development of coil coating and other categorical
effluent limitations and standards, chemical analysis data were
collected of raw wastewater (treatment influent) and treated
wastewater (treatment effluent) from 55 plants (126 data days)
sampled by EPA (or its contractor) using EPA sampling and
chemical analysis protocols. These data are the initial data
base for determining the effectiveness of L&S technology in
treating nine pollutants. Each of the plants in the initial data
base belongs to at least one of the following industry
categories: aluminum forming, battery manufacturing, coil coating
(including canmaking), copper forming, electroplating and
porcelain enameling. All of the plants employ pH adjustment and
hydroxide precipitation using lime or caustic, followed by
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Stokes' law settling (tank, lagoon or clarifier) for solids
removal. An analysis of this data was presented in the
development documents for the proposed regulations for coil
coating and procelain enameling (January 1981). Prior to
analyzing the data, some values were deleted from the data base.
These deletions were made to ensure that the data reflect
properly operated treatment systems. The following criteria were
used in making these deletions:
Plants where malfunctioning processes or treatment
systems at the time of sampling were identified.
Data days where pH was less than 7.0 for extended
periods of time or TSS was greater than 50 mg/1 (these
are prima facie indications of poor operation).
In response to the coil coating and porcelain enameling
proposals, some commenters claimed that it was inappropriate to
use data from some categories for regulation of other categories.
In response to these comments, the Agency reanalyzed the data.
An analysis of variance was applied to the data for the 126 days
of sampling to test the hypothesis of homogeneous plant mean raw
and treated effluent levels across categories by pollutant. This
analysis is described in the report "A Statistical Analysis of
the Combined Metals Industries Effluent Data" which is in the
administrative record supporting this rulemaking. Homogeneity is
the absence of statistically discernable differences among the
categories, while heterogeneity is the opposite, i.e., the
presence of statistically discernable differences. The main
conclusion drawn from the analysis of variance is that, with the
exception of electroplating, the categories included in the data
base are generally homogeneous with regard to mean pollutant
concentrations in both raw and treated effluent. That is, when
data from electroplating facilities are included in the analysis,
the hypothesis of homogeneity across categories is rejected.
When the electroplating data are removed from the analysis the
conclusion changes substantially and the hypothesis of
homogeneity across categories is not rejected. On the basis of
this analysis, the electroplating data were removed from the data
base used to determine limitations for the final coil coating,
porcelain enameling copper forming, aluminum forming, battery
manufacturing, nonferrous metals (Phase I), and canmaking
regulations and proposed regulations for nonferrous metals
forming.
Analytical data from nonferrous metals manufacturing phase II
treatment systems which include paired raw waste influent
treatment and treated effluent are limited to three plants with
lime precipitation and sedimentation systems. None of these
systems were deemed to be appropriate for consideration in
establishing treatment effectiveness concentration for nonferrous
metals manufacturing phase II. Two of the plants had large
non-scope flows entering the treatment system and the third had
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high TSS (N 1000 mg/1) concentrations at the outfall of its lime
and settle treatment system; concentrations indicative of poor
system operation.
EPA examined the homogeneity among nonferrous metals
manufacturing phase II subcategories, as well as across
nonferrous metals manufacturing phase I subcategories and the
combined metals data base. Homogeneity is the absence of
statistically discernable differences among mean untreated
pollutant concentrations observed in a set of data. The purpose
of these analyses was to check the Agency's engineering judgement
that the untreated wastewater characteristics observed in the
combined metals data. Establishment of similarity of raw wastes
through a statistical assessment provides further support to
EPA's assumption that lime and settle treatment reduces the toxic
metal pollutant concentrations in untreated nonferrous phase II
wastewater to concentrations achieved by the same technology
applied to the wastewater from the categories in the combined
metals data base. In general, the results of the analysis showed
that the nonferrous phase II subcategories are homogeneous with
respect to mean pollutant concentrations across subcategories.
Comparison of the untreated nonferrous metals manufacturing data
combined across subcategories and the combined metals data also
showed good agreement.
The homogeneity observed among the nonferrous phase II untreated
data and the combined metals data supports the hypothesis of
similar untreated wastewater characteristics and suggests that
lime .and settle treatment would reduce the concentrations of
toxic metal pollutants in the nonferrous metals manufacturing
phase II to concentrations comparable to those achievable by lime
and settle treatment of wastewater from the categories included
in the combined metals data base.
There were several exceptions to the general finding of
homogeneity among the industrial categories discussed above. The
exceptional cases include:
•1. The primary beryllium subcategory has higher beryllium
concentration's in the untreated wastewater than other plants in
phase II.
2. The secondary process metals subcategory has higher zinc
concentration's in the untreated wastewater than other plants in
phase II.
3. The untreated nickel concentrations in specifically
secondary tungsten and cobalt plants are higher than in the
plants in the combined metals data base.
EPA is considering the use of sulfide precipitation in
conjunction with lime and settle, and lime, settle and filtration
for these cases where the influent metals concentrations are
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higher than those observed in the combined metals data base.
These special cases are discussed in a memorandum entitled
"Analysis of the Wastewater Pollutant Concentrations from the
Phase II Subcategories of the Nonferrous Metals Manufacturing
Category," found in the record supporting this proposal. The
combined metals data base as discussed below is applicable to all
nonferrous metals manufacturing phase II wastewater as
demonstrated by the homogeneity.
Properly operated hydroxide precipitation and sedimentation will
result in effluent concentrations that are directly related to
pollutant solubilities. Since the nonferrous metals
manufacturing raw wastewater matrix contains the same toxic
pollutants in the same order of magnitude as the combined metals
data base, the treatment process effluent long-term performance
and variability will be quite similar. In addition, no
interfering properties (such as chelating agents) exist in
nonferrous metals manufacturing phase II wastewater that would
interfere with metal precipitation and so prevent attaining
concentrations calculated from the combined metals data base.
The statistical analysis provides support for the technical
engineering judment that electroplating wastewaters are
sufficiently different from the wastewaters of other industrial
categories in the data base to warrant removal of electroplating
data from the data base used to determine treatment
effectiveness.
For the purpose of determining treatment effectiveness,
additional data were deleted from the data base. These deletions
were made, "almost exclusively, in cases where effluent data
points were associated with low influent values. This was done
in two steps. First, effluent values measured on the same day as
influent values that were less than or equal to 0.1 mg/1 were
deleted. Second, the remaining data were screened for cases in
which all influent values at a plant were low although slightly
above the 0.1 mg/1 value. These data were deleted not as
individual data points but as plant clusters of data that were
consistently low and thus not relevent to assessing treatment. A
few data points were also deleted where malfunctions not
previously identified were recognized. The data basic to the
CMDB are displayed graphically in Figures VII-4 to 12 (Pages 299-304
).
After all deletions, 148 data points from 19 plants remained.
These data were used to determine the concentration basis of
limitations derived from the CMDB used for the proposed
nonferrous metals manufacturing phase I regulations.
The CMDB was reviewed following its use in a number of proposed
regulations (including nonferrous metals manufacturing phase I).
Comments pointed out a few errors in the data and the Agency's
review identified a few transcription errors and some data points
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that were appropriate for inclusion in the data that had not been
used previously because of errors in data record identification
numbers. Documents in the record of this rulemaking identify all
the changes, the reasons for the changes, and the effect of these
changes on the data base. Comments on other proposal regulations
asserted that the data base was too small and that the
statistical methods used were overly complex. Responses to
specific comments are provided in a document included in the
record of this rulemaking. The Agency believes that the data
base is adequate to determine effluent concentrations achievable
with lime and settle treatment. The statistical methods employed
in the analysis are well known and appropriate statistical
references are provided in the documents in the record that
describe the analysis.
The revised data base was reexamined for homogeneity. The
earlier conclusions were unchanged. The categories show good
overall homogeneity with respect to concentrations of the nine
pollutants in both raw and treated wastewaters with the exception
of electroplating.
The same procedures used in developing proposed limitations in
nonferrous metals manufacturing phase I from the combined metals
data base were then used on the revised data base. That is,
certain effluent data associated with low influent values were
deleted, and then the remaining data were fit to a lognormal
distribution to determine limitations values. The deletion of
data was done in two steps. First, effluent values measured on
the same day as influent values that were less than or equal to
0.1 mg/1 were deleted. Second, the remaining data were screened
for cases in which all influent values at a plant were low
although slightly above the 0.1 mg/1 value. These data were
deleted not as individual data points but as plant clusters of
data that were consistently low and thus not relevant to
assessing treatment.
The revised combined metals data base used for this proposed
regulation consists of 162 data points from 18 plants in the same
industrial categories used at proposal. The changes that were
made since proposal resulted in slight upward revisions of the
concentration bases for the limitations and standards for zinc
and nickel. The limitations for iron decrease slightly. The
other limitations were unchanged. A comparison of Table VII-19
in the final development document with Table VII-21 in the
proposal development document will show the exact magnitude of
the changes.
One-day Effluent Values
The basic assumption underlying the determination of treatment
effectiveness is that the data for a particular pollutant are
lognormally distributed by plant. The lognormal has been found
to provide a satisfactory fit to plant effluent data in a number
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of effluent guidelines categories and there was no evidence that
the lognormal was not suitable in the case of the CMDB. Thus, we
assumed measurements of each pollutant from a particular plant,
denoted by X, were assumed followed a lognormal distribution with
log mean n and log variance a2. The mean, variance and 99th
percent ile of X are then:
mean of X = E(X) = exp („ + a* /2)
variance of X = V(X) * exp (2 „ + «2) [exp(
99th percentile * X.99 = exp ( n + 2.33 a)
where exp is e, the base of the natural logarithm. The term
lognormal is used because the logarithm of X has a normal
distribution with mean ? and variance oz . Using the basic
assumption of lognormal ity the actual treatment effectiveness was
determined using a lognormal distribution that, in a sense,
approximates the distribution of an average of the plants in the
data base, i.e., an "average plant" distribution. The notion of
an "average plant" distribution is not a strict statistical
concept but is used here to determine limits that would represent
the performance capability of an average of the plants in the
data base.
This "average plant" distribution for a particular pollutant was
developed as follows: the log mean was determined by taking the
average of all the observations for the pollutant across plants.
The log variance was determined by the pooled within plant
variance. This is the weighted average -of the plant variances.
Thus, the log mean represents the average of all the data for the
pollutant and the log variance represents the average of the
plant log variances or average plant variability for the
pollutant.
The one day effluent values were determined as follows:
Let Xij = the jth observation on a particular pollutant at
plant i where
i = 1 , . . . , I
j = 1 , . . . , Ji
I = total number of plants
Ji = number of observations at plant i.
Then Yij = In Xij
where In means the natural logarithm.
Then y = log mean over all plants
I Ji
= I E yij/n,
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where n = total number of observations
I
I Ji
and V(y) = pooled log variance
I
* I (Ji - 1 ) Si2
i = 1
I
I (Ji - 1 )
i » 1
where Si2 = log variance at plant i
Jj = 1
= I (yij -.yi)
Jj = 1
yi = log mean at plant i.
Thus, y and V(y) are the log mean and log variance, respectively,
of the lognormal distribution used to determine the treatment
effectiveness. The estimated mean and 99th percentile of this
distribution form the basis for the long term average and daily
maximum effluent limitations, respectively. The estimates are
mean = E(X) * exp(y) n (0.5 V(y))
99th percentile = X.,, = exp [y + 2.33 V(y) ]
where * (.) is a Bessel function and exp is e, the base of the
natural logarithms (See Aitchison, J. and J.A.C. Brown, The
Loqnormal Distribution, Cambridge University Press, 1963). In
cases where zeros were present in the data, a generalized form of
the lognormal, known as the delta distribution was used (See
Aitchison and Brown, op. cit., Chapter 9).
For certain pollutants, this approach was modified slightly to
ensure that well operated lime and settle plants in all CMDB
categories would achieve the pollutant concentration values
calculated from the CMDB. For instance, after excluding the
electroplating data and other data that did not reflect pollutant
removal or proper treatment, the effluent copper data from the
copper forming plants were statistically significantly greater
than the copper data from the other plants. This indicated that
copper forming plants might have difficulty achieving an effluent
concentration value calculated from copper data from all CMDB
categories. Thus, copper effluent values shown in Table VII-14
(page 305 ) are based only on the copper effluent data from the
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copper forming plants. That is, the log mean for copper is the
mean of the logs of all copper values from the copper forming
plants only and the log variance is the pooled log variance of
the copper forming plant data only. A similar situation occurred
in the case of lead. That is, after excluding the electroplating
data, the effluent lead data from battery manufacturing were
significantly greater than the other categories. This indicated
that battery manufacturing plants might have difficulty achieving
a lead concentration calculated from all the CMDB categories.
The lead values proposed in nonferrous metals manufacturing phase
I were therefore based on the battery e therefore based on the
battery manufacturing lead data only. Comments on the proposed
battery manufacturing regulation objected to this procedure and
asserted that the lead concentration values were too low.
Following proposal, the Agency obtained additional lead effluent
data from a battery manufacturing facility with well operated
lime arid settle treatment. These data were combined with .the
proposal lead data and analyzed to determine the final treatment
effectiveness concentrations. The mean lead concentration is
unchanged at 0.12 mg/1 but the final one-day maximum and monthly
10-day average maximum increased to 0.42 and 0.20 mg/1,
respectively. A complete discussion of the lead data and
analysis is contained in a memorandum in the administrator record
for this rulemaking.
In the case of cadmium, after excluding the electroplating data
and data that did not reflect removal or proper treatment, there
were insufficient data to estimate the log variance for cadmium.
The variance used to determine the values shown in Table VI1-14
for cadmium was estimated by pooling the within plant variances
for all the other metals. Thus, the cadmium variability is the
average of the plant variability averaged over all the other
metals. The log mean for cadmium is the mean of the logs of the
cadmium observations only. A complete discussion of the data and
calculations for all the metals is contained in the
administrative record for this rulemaking.
Average Effluent Values
Average effluent values that form the basis for the monthly
limitations were developed in a manner consistent with the method
used to develop one-day treatment effectiveness in that the
lognormal distribution used for the one-day effluent values was
also used as the basis for the average values. That is, we
assume a number of consecutive measurements are drawn from the
distribution of daily measurements. The average of ten
measurements taken during a month was used as the basis for the
monthly average limitations. The approach used for the 10
measurements values was employed previously in regulations for
other categories and was promulgated for the nonferrous metals
manufacturing phase I. That is, the distribution of the average
of 10 samples from a lognormal was approximated by another
lognormal distribution. Although the approximation is not
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precise theoretically, there is empirical evidence based on
effluent data from a number of categories that the lognormal is
an adequate approximation for the distribution of small samples.
In the course of previous work the approximation was verified in
a computer simulation study (see "Development Document for
Existing Sources Pretreatment Standards for the Electroplating
Point Source Category", EPA 440/1-79/003, U.S. Environmental
Protection Agency, Washington, D.C., August 1979). We also note
that the average values were developed assuming independence of
the observations although no particular sampling scheme was
assumed .
Ten-Sample Average:
The formulas for the 10-sample limitations were derived on the
basis of simple relationships between the mean and variance of
the distributions of the daily pollutant measurements and the
average of 10 measurements. We assume the daily concentration
measurements for a particular pollutant, denoted by X, follow a
lognormal distribution with log mean and log variance denoted by
n and *2 , respectivey. Let X10 denote the mean of 10 consecutive
measurements. The following relationships then hold assuming the
daily measurements are independent:
mean of X10 = E(X10) = E(X)
variance of X10 = V(X10) = V(X) + 10.
Where E(X) and V(X) are the mean and variance of X, respectively,
defined above. We then assume that X10 follows a lognormal
distribution with log mean nlo and log standard deviation *2.
The mean and variance of X10 are then
E(X10) * exp („ 10 + 0.5 *22 10)
V(XIO) " exp (2 „ J0 + *210) [exp(
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Thirty Sample Average
Monthly average values based on the average of 30 daily
measurements were also calculated. These are included because
monthly limitations based on 30 samples have been used in the
past and for comparison with the 10 sample values. The average
values based on 30 measurements are determined on the basis of a
statistical result known as the Central Limit Theorem. This
Theorem states that, under general and nonrestrictive
assumptions, the distribution of a sum of a number of random
variables, say n, is approximated by the normal distribution.
The approximation improves as the number of variables, n,
increases. The Theorem is quite general in that no particular
distributional form is assumed for the distribution of the
individual variables. In most applications (as in approximating
the distribution of 30-day averages) the Theorem is used to
approximate the distribution of the average of n observations of
a random variable. The result makes it possible to compute
approximate probability statements about the average in a wide
range of cases. For instance, it is possible to compute a value
below which a specified percentage (e.g., 99 percent) of the
averages of n observations are likely to fall. Most textbooks
state that 25 or 30 observations are sufficient for the
approximation to be valid. In applying the Theorem to the
distribution of the 30 day average effluent values, we
approximate the distribution of the average of 30 observations
drawn from the distribution of daily measurements and use the
estimated 99th percentile of this distribution.
Thirty Sample Average Calculation
The formulas for the 30 sample average were based on an
application of the Central Limit Theorem. According to the
Theorem, the average of 30 observations drawn from the
distribution of daily measurements, denoted by X30, is
approximately normally distributed. The mean and variance of X30
are:
mean of X30 - E(X30) = E(X)
variance of X30 = V(X30) = V(X) -r 30.
The 30 sample average value was determined by the estimate of the
approximate 99th percentile of the distribution of the 30 sample
average given by
X30(.99) = E(X) » 2.33 V(X) -r 30
where
E(X) = exp(y) n (0.5v(y))
and V(X) - exp(2y) [ n(2V(y)) » n n-2 V(y)]
n-1
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The formulas for E(X) and V(X) are estimates of E(X) and V(X),
respectively, given in Aitchison, J. and J.A.C. Brown, The
Loqnormal Distribution, Cambridge University Press, 1963, page
45.
Application
In response to the proposed coil coating and porcelain enameling
regulations, the Agency received comments pointing out that
permits usually required less than 30 samples to be taken during
a month while the monthly average used as the basis for permits
and pretreatment requirements usually is based on the average of
30 samples.
In applying the treatment effectiveness values to regulations we
have considered the comments, examined the sampling frequency
required by many permits and considered the change in values of
averages depending on the number of consecutive sampling days in
the averages. The most common frequency of sampling required in
permits is about ten samples per month or slightly greater than
twice weekly. The 99th percentiles of the distribution of
averages of ten consecutive sampling days are not substantially
different from the 99th percentile of the distribution's 30-day
average. (Compared to the one-day maximum, the ten-day average
is about 80 percent of the difference between one- and 30-day
values). Hence the ten-day.average provides a reasonable basis
for a monthly average limitation and is typical of the sampling
frequency required by existing permits.
The monthly average limitation is to be achieved in all permits
and pretreatment standards regardless of the number of samples
required to be analyzed and averaged by the permit or the
pretreatment authority.
Additional Pollutants
Nineteen additional pollutant parameters were evaluated to
determine the performance of lime and settle treatment systems in
removing them from industrial wastewater. Performance data for
these parameters is not a part of the CMDB so other data
available to the Agency has been used to determine the long term
average performance of lime and settle technology for each
pollutant. These data indicate that the concentrations shown in
Table VII-15 (page 306 ) are reliably attainable with hydroxide
precipitation and settling. Treatment effectiveness values were
calculated by multiplying the mean performance from Table VI1-15
(page 306 ) by the appropriate variability factor. (The
variability factor is the ratio of the value of concern to the
mean). The pooled variability factors are: one-day maximum -
4.100; ten-day average - 1.821; and 30-day average - 1.618 these
one-, ten-, and thirty-day values are tabulated in Table VII-21
(page 311 ) .
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In establishing which data were suitable for use in Table VII-14
two factors were heavily weighed; (1) the nature of the
wastewater; and (2) the range of pollutants or pollutant matrix
in the raw wastewater. These data have been selected from
processes that generate dissolved metals in the wastewater and
which are generally free from complexing agents. The pollutant
matrix was evaluated by comparing the concentrations of
pollutants found in the raw wastewaters with the range of
pollutants in the raw wastewaters of the combined metals data
set. These data are displayed in Tables VII-16 (page 306 ) and
VII-17 (page 307 ) and indicate that there is sufficient
similarity in the raw wastes to logically assume transferability
of the treated pollutant concentrations to the combined metals
data base. Nonferrous manufacturing wastewaters also were
compared to the wastewaters from plants in categories from which
treatment effectiveness values were calculated. The available
data on these added pollutants do not allow homogeneity analysis
as was performed on the combined metals data base. The data
source for each added pollutant is discussed separately.
Antimony (Sb) - The achievable performance for antimony is based
on data from a battery and secondary lead plant. Both EPA
sampling data and recent permit data (1978-1982) confirm the
achievability of 0.7 mg/1 in the battery manufacturing wastewater
matrix included in the combined data set. The 0.7 mg/1
concentration is achieved, at a nonferrous metals manufacturing
and secondary lead plant with the comparable untreated wastewater
matrix shown in Table VII-17.
Arsenic (As) - The achievable performance of 0.5 mg/1 for arsenic
is based on permit data from two nonferrous metals manufacturing
plants. The untreated wastewater matrix shown in Table VII-17
(page 307 ) is comparable with the combined data set matrix.
Beryllium (Be) - The treatability of beryllium is transferred
from the nonferrous metals manufacturing industry. The 0.3 mg/1
performance is achieved at a beryllium plant with the comparable
untreated wastewater matrix shown in Table VII-17.
Mercury (Hg) - The 0.06 mg/1 treatability of mercury is based on
data from four battery plants. The untreated wastewater matrix
at these plants was considered in the combined metals data set.
Selenium (Se) - The 0.30 mg/1 treatability of selenium is based
on recent permit data from one of the nonferrous metals
manufacturing plants also used for antimony performance. The
untreated wastewater matrix for this plant is shown in Table
VII-17.
Silver - The treatability of silver is based on a 0.1 mg/1
treatability estimate from the inorganic chemicals industry.
Additional data supporting a treatability as stringent or more
stringent than 0.1 mg/1 is also available from seven nonferrous
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metals manufacturing plants. The untreated wastewater matrix for
these plants is comparable and summarized in Table VI1-17.
Thallium (Tl) - The 0.50 mg/1 treatability for thallium is
transferred from the inorganic chemicals industry. Although no
untreated wastewater data are available to verify comparability
with the combined metals data set plants, no other sources of
data for thallium treatability could be identified.
Aluminum (Al) - The 2.24 mg/1 treatability of aluminum is based
on the mean performance of three aluminum forming plants and one
coil coating plant. These plants are from categories included in
the combined metals data set, assuring untreated wastewater
matrix comparability.
Boron (B) - The achievable performance of 0.27 mg/1 for boron is
based on data- from a metallurgical acid plant associated with a
primary molybdenum roasting operation. The untreated wastewater
matrix shown in Table VII-17 (page 307) is comparable with the
combined metals data base.
Cobalt (Co) - The 0.05 mg/1 treatability is based on nearly
complete removal of cobalt at a porcelain enameling plant with a
mean untreated wastewater cobalt concentration of 4.31 mg/1. In
this case, the analytical detection using aspiration techniques
for this pollutant is used as the basis of the treatability.
Porcelain enameling was considered in the combined metals data
base, assuring untreated wastewater matrix comparability.
Fluoride (F) - The 14.5 mg/1 treatability of fluoride generally
applicable to metals processing is based on the mean performance
(47 samples) from two electronics manufacturing phase II plants.
The untreated wastewater matrix for this plant shown in Table
VII-17 is comparable to the combined metals data set.
Germanium (G) - The treatability of Germanium 13 assured to be
the same as the treatability level for chromium (0.084 mg/1) for
reasons discussed for titanium and indium (see below). The
Agency requests data on the treatability of germanium and
solicits comment on the assumption that the achievable
performance for germanium should be similar to that of chromium.
Indium (In) - The treatability for indium is assumed to be the
same as the treatability for chromium (0.084 mg/1). Lacking any
treated effluent data for indium, a comparison was made between
the theoretical solubilities of indium and the metals in the
combined Metals Data Base: cadmium, chromium, copper, lead,
nickel and zinc. The theoretical solubility of indium (2.5 x
10~7) is more similar to the theoretical solubility of chromium
(1.65 x 10~8 mg/1) than it is to the theoretical solubilities of
cadmium, copper, lead, nickel or zinc. The theoretical
solubilities of these metals range from 20 x 10~3 2.2 x 10~5
mg/1. This comparison is further supported by the fact that
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indium and chromium both form hydroxides in the trivalent state.
Cadmium, copper, lead, nickel and zinc all from divalent
hydroxides.
The Agency requests data on the treatability of indium and
solicits comment on the assumption that the achievable
performance for indium should be similar to that of chromium.
Molybdenum (Mo) - The achievable performance of 1.41 mg/1 from
molybdenum is based on data from a metallurgical acid plant
associated with a primary molybdenum roasting operation. The
untreated wastewater matrix shown in Table VII-17 (page 307 ) is
comparable with the combined metals data base.
Phosphorus (P) - The 4.08 mg/1 treatability of phosphorus is
based on the mean of 44 samples including 19 samples from the
Combined Metals Data Base and 25 samples from the electroplating
data base. Inclusion of electroplating data with the combined
metals data was considered appropriate, since the removal
mechanism for phosphorus is a precipitation reaction with calcium
rather than hydroxide.
Radium 226 (Ra 226) - The achievable performance of 6.17
picocuries per liter for radium 226 is based on data from one
facility in the uranium subcategory of the Ore Mining and
Dressing category which practices barium chloride coprecipitation
in conjunction with lime and settle treatment. The untreated
wastewater matrix shown in table VII-17 (page 307 ) is comparable
with the combined metals data base.
Tin (Sin) - The achievable performance of 1.07 mg/1 for tin is
based on data from one secondary tin plant. The untreated
wastewater matrix shown in table VII-17 (page 307 ) is comparable
with the combined metals data base.
Titanium (Ti) - The treatability of titanium is assumed to be the
same as the treatability of chromium (0.084 mg/1). Lacking any
treated effluent data for titanium, a comparison was made between
the theoretical solubilities of titanium and the metals in the
combined Metals Data Base: cadmium, chromium, copper, lead,
nickel and zinc. The theoretical solubility of titanium (2.1 x
10-' mg/1) is more similar to the theoretical solubility of
chromium (1.65 x 10~e mg/1) than it is to the theoretical
solubilities of cadmium, copper, lead, nickel or zinc. The
theoretical solubilities of these metals range from 2.0 x 10~3
2.2 x 10~5 mg/1. This comparison is further supported by the
fact that titanium and chromium both from hydroxides in the
trivalent state. Cadmium, copper, lead, nickel and zinc all form
divalent hydroxides. The Agency requests data on the
treatability of titanium and solicits comment on the assumption
that the achievable performance for titanium should be similar to
that of chromium.
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Uranium (U) - The achievable performance of 1.23 mg/1 for uranium
is based on data from one facility in the uranium subcategory of
the Ore Mining and Dressing category which practices chemical
precipitation and sedimentation treatment. The untreated
wastewater matrix shown in table VII-17 (page 307 ) is comparable
with the combined metals data base.
LS&F Performance
Tables VII-18 and VII-19 (pages 308 and 309 ) show long term data
from two plants which have well operated precipitation-settling
treatment followed by filtration. The wastewaters from both
plants contain pollutants from metals processing and finishing
operations (multi-category). Both plants reduce hexavalent
chromium before neutralizing and precipitating metals with lime.
A clarifier is used to remove much of the solids load and a
filter is used to "polish" or complete removal of suspended
solids. Plant A uses a pressure filter, while Plant B uses a
rapid sand filter.
Raw wastewater data was collected only occasionally at each
facility and the raw wastewater data is presented as an
indication of the nature of the wastewater treated. Data from
plant A was received as a statistical summary and is presented as
received. Raw laboratory data was collected at plant B and
reviewed for spurious points and discrepancies. The method of
treating the data base is discussed below under lime, settle, and
filter treatment effectiveness.
Table VII-20 (page 310 ) shows long-term data for zinc and cadmium
removal at Plant C, a primary zinc smelter, which operates a LS&F
system. This data represents about 4 months (103 data days)
taken immediately before the smelter was closed. It has been
arranged similarily to Plants A and B for comparison and use.
These data are presented to demonstrate the performance of
precipitation-settling-filtration (LS&F) technology under actual
operating conditions and over a long period of time.
It should be noted that the iron content of the raw wastewater of
plants A and B is high while that for Plant C is low. This
results, for plants A and B, in co-precipitation of toxic metals
with iron. Precipitation using high-calcium lime for pH control
yields the results shown above. Plant operating personnel
indicate that this chemical treatment combination (sometimes with
polymer assisted coagulation) generally produces better and more
consistent metals removal than other combinations of sacrificial
metal ions and alkalis.
The LS&F performance data presented here are based on systems
that provide polishing filtration after effective L&S treatment.
We have previously shown that L&S treatment is equally applicable
to wastewaters from the five categories because of the
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homogeneity of its raw and treated wastewaters, and other
factors. Because of the similarity of the wastewaters after L&S
treatment, the Agency believes these wastewaters are equally
amenable to treatment using polishing filters added to the L&S
treatment system. The Agency concludes that LS&F data based on
porcelain enameling and nonferrous metals manufacturing phase I
is directly applicable to The 21 subcategories in nonferrous
metals manufacturing phase II.
Analysis o_f Treatment System Effectiveness
Data are presented in Table VI1-14 showing the mean, one-day, 10-
day, and 30-day values for nine pollutants examined in the L&S
combined metals data base. The pooled variability factor for
seven metal pollutants (excluding cadmium because of the small
number of data points) was determined and is used to estimate
one-day, 10-day and 30-day values. (The variability factor is
the ratio of the value of concern to the mean: the pooled
variability factors are: one-day maximum - 4.100; ten-day average
1.821; and 30-day average - 1.618.) For values not calculated
from the CMDB as previously discussed, the mean value for
pollutants shown in Table VII-15 were multiplied by the
variability factors to derive the value to obtain the one-, ten-
and 30-day values. These are tabulated in Table VII-21.
The treatment effectiveness for sulfide precipitation and
filtration has been calculated similarily. Long term average
values shown in Table VI1-6 (page 301 ) have been multiplied by
the appropriate variability factor to estimate one-day maximum,
and ten-day and 30-day average values. Variability factors
developed in the combined metals data base were used because the'
raw wastewaters are identical and the treatment methods are
similar as both use chemical precipitation and solids removal to
control metals.
LS&F technology data are presented in Tables VII-18 and VII-19.
These data represent two operating plants (A and B) in which the
technology has been installed and operated for some years. Plant
A data was received as a statistical summary and is presented
without change. Plant B data was received as raw laboratory
analysis data. Discussions with plant personnel indicated that
operating experiments and changes in materials and reagents and
occasional operating errors had occurred during the data
collection period. No specific information was available on
those variables. To sort out high values probably caused by
methodological factors from random statistical variability, or
data noise, the plant B data were analyzed. For each of four
pollutants (chromium, nickel, zinc, and iron), the mean and
standard deviation (sigma) were calculated for the entire data
set. A data day was removed from the complete data set when any
individual pollutant concentration for that day exceeded the sum
of the mean plus three sigma for that pollutant. Fifty-one data
days (from a total of about 1300) were eliminated by this method.
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Another approach was also used as a check on the above method of
eliminating certain high values. The minimum values of raw
wastewater concentrations from Plant B for the same four
pollutants were compared to the total set of values for the
corresponding pollutants. Any day on which the treated
wastewater pollutant concentration exceeded the minimum value
selected from raw wastewater concentrations for that pollutant
was discarded. Forty-five days of data were eliminated by that
procedure. Forty-three days of data in common were eliminated by
either procedures. Since common engineering practice (mean plus
3 sigma) and logic (treated wastewater concentrations should be
less than raw wastewater concentrations) seem to coincide, the
data base with the 51 spurious data days eliminated is the basis
for all further analysis. Range, mean plus standard deviation
and mean plus two standard deviations are shown in Tables VII-18
and VII-19 for Cr, Cu, Ni, Zn and Fe.
The Plant B data was separated into 1979, 1978, and total data
base (six years) segments. With the statistical analysis from
Plant A for 1978 and 1979 this in effect created five data sets
in which there is some overlap between the individual years and
total data sets from Plant B. By comparing these five parts it
is apparent that they are quite similar and all appear to be from
the same family of numbers. The largest mean found among the
five data sets for each pollutant was selected as the long term
mean for LS&F technology and is used as the LS&F mean in Table
VII-21.
Plant C data was used as a basis for cadmium removal performance
and as a check on the zinc values derived from Plants A and B.
The cadmium data is displayed in Table VII-20 (page 310 ) and is
incorporated into Table VII-21 for LS&F. The zinc data was
analyzed for compliance with the 1-day and 30-day values in Table
VII-21; no zinc value of the 103 data points exceeded the 1-day
zinc value of 1.46 mg/1. The 103 data points were separated into
blocks of 30 points and averaged. Each of the 3 full 30-day
averages was less than the Table VII-21 value of 0.45 mg/1.
Additionally the Plant C raw wastewater pollutant concentrations
(Table VII-20) are well within the range of raw wastewater
concentrations of the combined metals data base (Table VI1-16),
further supporting the conclusion that Plant C wastewater data is
compatible with similar data from Plants A and B.
Concentration values for regulatory use are displayed in Table
VII-21. Mean one-day, ten-day and 30-day values for L&S for nine
pollutants were taken from Table VII-14; the remaining L&S values
were developed using the mean values in Table VII-15 and the mean
variability factors discussed above.
LS&F mean values for Cd, Cr, Ni, Zn and Fe are derived from
plants A, B, and C as discussed above. One-, ten- and thirty-day
values are derived by applying the variability factor developed
from the pooled data base for the specific pollutant to the mean
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for that pollutant. Other LS&F values are calculated using the
long term average or mean and the appropriate variability
factors.
Copper levels achieved at Plants A and B may be lower than
generally achievable because of the high iron content and low
copper content of the raw wastewaters. Therefore, the mean
concentration value from plants A and B achieved is not used/ the
LS&F mean for copper is derived from the L&S technology.
L&S cyanide mean levels shown in Table VI1-8 are ratioed to one-
day, ten-day and 30-day values using mean variability factors.
LS&F mean cyanide is calculated by applying the ratios of
removals L&S and LS&F as discussed previously for LS&F metals
limitations. The treatment method used here is cyanide
precipitation. Because cyanide precipitation is limited by the
same physical processes as the metal precipitation, it is
expected that the variabilities will be similar. Therefore, the
average of the metal variability factors has been used as a basis
for calculating the cyanide one-day, ten-day and thirty-day
average treatment effectiveness values.
The filter performance for removing TSS as shown in Table VI1-9
(page 303) yields a mean effluent concentration of 2.61 mg/1 and
calculates to a 10-day average of 4.33, 30-day average of 3.36
mg/1; a one-day maximum of 8.88. These calculated values more
than amply support the classic thirty-day and one-day values of
10 mg/1 and 15 mg/1, respectively, which are used for LS&F.
Although iron concentrations were decreased in some LS&F
operations, some facilities using that treatment introduce iron
compounds to aid settling. Therefore, the one-day, ten-day and
30-day values for iron at LS&F were held at the L&S level so as
to not unduly penalize the operations which use the relatively
less objectionable iron compounds to enhance removals of toxic
metals.
The removal of additional fluoride by adding polishing filtration
is suspect because lime and settle technology removes calcium
fluoride to a concentration near its solubility. The one
available data point appears to question the ability of filters
to achieve high removals of additional fluoride. The fluoride
concentrations demonstrated for L&S are used as the treatment
effectiveness for LS&F.
MINOR TECHNOLOGIES
Several other treatment technologies were considered for possible
application in this subcategory. These technologies are
presented here.
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8. Carbon Adsorption
The use of activated carbon to remove dissolved organics from
water and wastewater is a long demonstrated technology. It is
one of the most efficient organic removal processes available.
This sorption process is reversible, allowing activated carbon to
be regenerated for reuse by the application of heat and steam or
solvent. Activated carbon has also proved to be an effective
adsorbent for many toxic metals, including mercury.- Regeneration
of carbon which has adsorbed significant metals, however, may be
difficult.
The term activated carbon applies to any amorphous form of carbon
that has been specially treated to give high adsorption
capacities. Typical raw materials include coal, wood, coconut
shells, petroleum base residues, and char from sewage sludge
pyrolysis. A carefully controlled process of dehydration,
carbonization, and oxidation yields a product which is called
activated carbon. This material has a high capacity for
adsorption due primarily to the large surface area available for
adsorption, 500 to 1500 mz/sq m resulting from a large number of
internal pores. Pore sizes generally range from 10 to TOO
angstroms in radius.
Activated carbon removes contaminants from water by the process
of adsorption, or the attraction and accumulation of one
substance on the surface of another. Activated carbon
preferentially adsorbs organic compounds and, because of this
selectivity, is particularly effective in removing organic
compounds from aqueous solution.
Carbon adsorption requires pretreatment to remove excess
suspended solids, oils, and greases. Suspended solids in the
influent should be less than 50 mg/1 to minimize backwash
requirements; a downflow carbon bed can handle much higher levels
(up to 2000 mg/1) but requires frequent backwashing. Backwashing
more than two or three times a day is not desirable; at 50 mg/1
suspended solids, one backwash will suffice. Oil and grease
should be less than about 10 mg/1. A high level of dissolved
inorganic material in the influent may cause problems with
thermal carbon reactivation (i.e., scaling and loss of activity)
unless appropriate preventive steps are taken. Such steps might
include pH control, softening, or the use of an acid wash on the
carbon prior to reactivation.
Activated carbon is available in both powdered and granular form.
An adsorption column packed with granular activated carbon is
shown in Figure VII-17 (page333 ). Powdered carbon is less
expensive per unit weight and may have slightly higher adsorption
capacity, but it is more difficult to handle and to regenerate.
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Application and Performance. Carbon adsorption is used to remove
mercury from wastewaters. The removal rate is influenced by the
mercury level in the influent to the adsorption unit. In Table
VII-24, removal levels found at three manufacturing facilities
are listed.
In the aggregate these data indicate that very low effluent
levels could be attained from any raw waste by use of multiple
adsorption stages. This is characteristic of adsorption
processes.
Isotherm tests have indicated that activated carbon is very
effective in adsorbing 65 percent of the organic priority
pollutants and is reasonably effective for another 22 percent.
Specifically, for the organics of particular interest, activated
carbon was very effective in removing 2,4-dimethylphenol,
f luoranthene, isophorone, naphthalene, all phthalates", and
phenanthrene. It was reasonably effective on 1,1,1-
trichloroethane, 1,1-dichloroethane, phenol, and toluene. Table
VII-22 (page 313 ) summarizes the treatment effectiveness for most
of the organic priority pollutants by activated carbon as
compiled by EPA. Table VII-23 (page 3i4 ) summarizes classes of
organic compounds together with examples of organics that are
readily adsorbed on carbon.
Activated carbon adsorption preliminary treatment was considered
for control of net precipitation discharges of total phenols
(4AAP_, 2-chlorophenol and phenol from red mud ponds in the
bauxite refining subcategory. This treatment technology was
selected because discharges from red mud ponds do not appear to
be effectively controlled by existing treatment. Activated
carbon is not demonstrated in this or any other application
within the bauxite refining subcategory. Therefore, performance
of this technology is transferred from the iron and steel
manufacturing category.
The treatment performance used for activated carbon to calculate
mass limitations for total phenols (4AAP), 2-chlorophenol and
phenol is based on the quantification limit of 0.010 mg/1. This
concentration is achievable, assuming sufficient carbon is used
in the column. In an activated carbon column is determined only
by the amount of carbon present and a suitable contact time.
Therefore, the 0.010 mg/1 is achievable by assuming a
conservative ratio for carbon exhaustion (usage). The exhaustion
rate used by the Agency was based on laboratory carbon adsorption
tests using wastewater from the nonferrous metals manufacturing
category.
Advantages and Limitations. The major benefits of carbon
treatment include applicability to a wide variety of organics and
high removal efficiency. Inorganics such as cyanide, chromium,
and mercury are also removed effectively. Variations in
concentration and flow rate are well tolerated. The system is
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compact, and recovery of adsorbed materials is sometimes
practical. However, destruction of adsorbed compounds often
occurs during thermal regeneration. If carbon cannot be
thermally desorbed, it must be disposed of along with any
adsorbed pollutants. The capital and operating costs of thermal
regeneration are relatively high. Cost surveys show that thermal
regeneration is generally economical when carbon use exceeds
about 1,000 Ib/day. Carbon cannot remove low molecular weight or
highly soluble organics. It also has a low tolerance for
suspended solids, which must be removed to at least 50 mg/1 in
the influent water.
Operational Factors. Reliability: This system should be very
reliable with upstream protection and proper operation and
maintenance procedures.
Maintainability: This system requires periodic regeneration or
replacement of spent carbon and is dependent upon raw waste load
and process efficiency.
Solid Waste Aspects: Solid waste from this process is
contaminated activated carbon that requires disposal. Carbon
undergoes regeneration, reduces the solid waste problem by
reducing the frequency of carbon replacement.
Demonstration Status. Carbon adsorption systems have been
demonstrated to be practical and economical in reducing COD, BOD,
and related parameters in secondary municipal and industrial
wastewaters; in removing toxic or refractory organics from
isolated industrial wastewaters; in removing and recovering
certain organics from wastewaters; and in removing and some times
recovering selected inorganic chemicals from aqueous wastes.
Carbon adsorption is a viable and economic process for organic
waste streams containing up to 1 to 5 percent of refractory or
toxic organics. Its applicability for removal of inorganics such
as metals has also been demonstrated.
9. Centrifuqation
Centrifugation is the application of centrifugal force to
separate solids and liquids in a liquid-solid mixture or to
effect concentration of the solids. The application of
centrifugal force is effective because of the density
differential normally found between the insoluble solids and the
liquid in which they are contained. As a waste treatment
procedure, centrifugation is applied to dewatering of sludges.
One type of centrifuge is shown in Figure VII-18 (page 334 ).
There are three common types of centrifuges; disc, basket, and
conveyor. All three operate by removing solids under the
influence of centrifugal force. The fundamental difference among
the three types is the method by which solids are collected in
and discharged from the bowl.
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In the disc centrifuge, the sludge feed is distributed between
narrow channels that are present as spaces between stacked
conical discs. Suspended particles are collected and discharged
continuously through small orifices in the bowl wall. The
clarified effluent is discharged through an overflow weir.
A second type of centrifuge which is useful in dewatering sludges
is the basket centrifuge. In this type of centrifuge, sludge
feed is introduced at the bottom of the basket, and solids
collect at the bowl wall while clarified effluent overflows the
lip ring at the top. Since the basket centrifuge does not have
provision for continuous discharge of collected cake, operation
requires interruption of the feed for cake discharge for a minute
or two in a 10 to 30 minute overall cycle.
The third type of centrifuge commonly used in sludge dewatering
is the conveyor type. Sludge is fed through a stationary feed
pipe into a rotating bowl in which the solids are settled out
against the bowl wall by centrifugal force. From the bowl wall,
the solids are moved by a screw to the end of the machine, at
which point they are discharged. The liquid effluent is
discharged through ports after passing the length of the bowl
under centrifugal force.
Application And Performance. Virtually all industrial waste
treatment systems producing sludge can use centrifugation to
dewater it. Centrifugation is currently being used by a wide
range of industrial concerns.
The performance of sludge dewatering by centrifugation depends on
the feed rate, the rotational velocity of the drum, and the
sludge composition and concentration. Assuming proper design and
operation, the solids content of the sludge can be increased to
20 to 35 percent.
Advantages And Limitations. Sludge dewatering centrifuges have
minimal space requirements and show a high degree of effluent
clarification. The operation is simple, clean, and relatively
inexpensive. The area required for a centrifuge system
installation is less than that required for a filter system or
sludge drying bed of equal capacity, and the initial cost is
lower.
Centrifuges have a high power cost that partially offsets the low
initial cost. Special consideration must also be given to
providing sturdy foundations and soundproofing because of the
vibration and noise that result from centrifuge operation.
Adequate electrical power must also be provided since large
motors are required. The major difficulty encountered in the
operation of centrifuges has been the disposal of the concentrate
which is relatively high in suspended, non-settling solids.
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Operational Factors. Reliability: Centrifugation is highly
reliable with proper control of factors such as sludge feed,
consistency, and temperature. Pretreatment such as grit removal
and coagulant addition may be necessary, depending on the
composition of the sludge and on the type of centrifuge employed.
Maintainability: Maintenance consists of periodic lubrication,
cleaning, and inspection. The frequency and degree of inspection
required varies depending on the type of sludge solids being
dewatered and the maintenance service conditions. If the sludge
is abrasive, it is recommended that the first inspection of the
rotating assembly be made after approximately 1,000 hours of
operation. -If the sludge is not abrasive or corrosive, then the
initial inspection might be delayed. Centrifuges not equipped
with a continuous sludge discharge system require periodic
shutdowns for manual sludge cake removal.
Solid Waste Aspects: Sludge dewatered' in the centrifugation
process may be disposed of by landfill. The clarified effluent
(centrate), if high in dissolved or suspended solids, may require
further treatment prior to discharge.
Demonstration Status. Centrifugation is currently used in a
great many commercial applications to dewater sludge. Work is
underway to improve the efficiency, increase the capacity, and
lower the costs associated with centrifugation.
10. Coalescing
The basic principle of coalescence involves the preferential
wetting of a coalescing medium by oil droplets which accumulate
on the medium and then rise to the surface of the solution as
they combine to form larger particles. The most important
requirements for coalescing media are wettability for oil and
large surface area. Monofilament line is sometimes used as a
coalescing medium.
Coalescing stages may be integrated with a wide variety of
gravity oil separation devices, and some systems may incorporate
several coalescing stages. In general, a preliminary oil
skimming step is desirable to avoid overloading the coalescer.
One commercially marketed system for oily waste treatment
combines coalescing with inclined plate separation and
filtration. In this system, the oily wastes flow into an
inclined plate settler. This unit consists of a stack of
inclined baffle plates in a cylindrical container with an oil
collection chamber at the top. The oil droplets rise and impinge
upon the undersides of the plates. They then migrate upward to a
guide rib which directs the oil to the oil collection chamber,
from which oil is discharged for reuse or disposal.
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The oily water continues on through another cylinder containing
replaceable filter cartridges, which remove suspended particles
from the waste. From there the wastewater enters a final
cylinder in which the coalescing material is housed. As the oily
water passes through the many small, irregular, continuous
passages in the coalescing material, the oil droplets coalesce
and rise to an oil collection chamber.
Application and Performance. Coalescing is used to treat oily
wastes which do not separate readily in simple gravity systems.
The three-stage system described above has achieved effluent
concentrations of 10 to 15 mg/1 oil and grease from raw waste
concentrations of 1000 mg/1 or more.
Advantages and Limitations. Coalescing allows removal of oil
droplets too finely dispersed for conventional gravity
separation-skimming technology. It also can significantly reduce
the residence times (and therefore separator volumes) required to
achieve separation of oil from some wastes. Because of its
simplicity, coalescing provides generally high reliability and
low capital and operating costs. Coalescing is not generally
effective in removing soluble or chemically stabilized emulsified
oils. To avoid plugging, coalescers must be protected by
pretreatment from very high concentrations of free oil and grease
and suspended solids. Frequent replacement of prefilters may be
necessary when raw waste oil concentrations are high.
Operational Factors. Reliability': Coalescing is inherently
highly reliable since there are no moving parts, and the
coalescing substrate (monofilament, etc.) is inert in the
process and therefore not subject to frequent regeneration or
replacement requirements. Large loads or inadequate
pretreatment, however, may result in plugging or bypass of
coalescing stages.
Maintainability: Maintenance requirements are generally limited
to replacement of the coalescing medium on an infrequent basis.
Solid Waste Aspects: No appreciable solid waste is generated by
this process.
Demonstration Status. Coalescing has been fully demonstrated in
industries generating oily wastewater, although none are
currently in use at any nonferrous metals manufacturing
facilities.
11 . Cyanide Oxidation by_ Chlorine
Cyanide oxidation using chlorine is widely useu in industrial
waste treatment to oxidize cyanide. Chlorine can be utilized in
either the elemental or hypochlorite forms. This classic
procedure can be illustrated by the following two step chemical
reaction:
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1. C12 + NaCN + 2NaOH > NaCNO + 2NaCl + H20
2. 3C12 + 6NaOH + 2NaCNO > 2NaHC03 + N2 + 6NaCl + 2H20
The reaction presented as Equation 2 for the oxidation of cyanate
is the final step in the oxidation of cyanide. A complete system
for the alkaline chlorination of cyanide is shown in Figure VII-
19 (page 335).
The alkaline chlorination process oxidizes cyanides to carbon
dioxide and nitrogen. The equipment often consists of an
equalization tank followed by two reaction tanks, although the
reaction can be carried out in a single tank. Each tank has an
electronic recorder-controller to maintain required conditions
with respect to pH and oxidation reduction potential (ORP). In
the first reaction tank, conditions are adjusted to oxidize
cyanides to cyanates. To effect the reaction, chlorine is
metered to the reaction tank as required to maintain the ORP in
the range of 350 to 400 millivolts, and 50 percent aqueous
caustic soda is added to maintain a pH range of 9.5 to 10. In
the second reaction tank, conditions are maintained to oxidize
cyanate to carbon dioxide and nitrogen. The desirable ORP and pH
for this reaction are 600 millivolts and a pH of 8.0. Each of
the reaction tanks is equipped with a propeller agitator designed
to provide approximately one turnover per minute. Treatment by
the batch process is accomplished by using two tanks, one for
collection of water over a specified time period, and one for the
treatment of an accumulated batch. If dumps of concentrated
wastes are frequent, another tank may be required to equalize the
flow to the treatment tank. When the holding tank is full, the
liquid "is transferred to the reaction tank for treatment. After
treatment, the supernatant is discharged and the sludges are
collected for removal and ultimate disposal.
Application and Performance. The oxidation of cyanide waste by
chlorine is a classic process and is found in most industrial
plants using cyanide. This process is capable of achieving
effluent levels that are nondetectable. The process is
potentially applicable to battery facilities where cyanide is a
component in cell wash formulations.
Advantages and Limitations. Some advantages of chlorine
oxidation for handling process effluents are operation at ambient
temperature, suitability for automatic control, and low cost.
Disadvantages include the need for careful pH control, possible
chemical interference in the treatment of mixed wastes, and the
potential hazard of storing and handling chlorine gas.
Operational Factors. Reliability: Chlorine oxidation is highly
reliable with proper monitoring and control and proper
pretreatment to control interfering substances.
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Maintainability: Maintenance consists of periodic removal of
sludge and recalibration of instruments.
Solid Waste Aspects: There is no solid waste problem associated
with chlorine oxidation.
Demonstration Status. The oxidation of cyanide wastes by
chlorine is a widely used process in plants using cyanide in
cleaning and metal processing baths. Alkaline chlorination is
also used for cyanide treatment in a number of inorganic chemical
facilities producing hydroganic acid and various metal cyanides.
12. Cyanide Oxidation By Ozone
Ozone is a highly reactive oxidizing agent which is approximately
ten times more soluble than oxygen on a weight basis in water.
Ozone may be produced by several methods, but the silent
electrical discharge method is predominant in the field. The
silent electrical discharge process produces ozone by passing
oxygen or air between electrodes separated by an insulating
material. A complete ozonation system is represented in Figure
VII-20 (page 336).
Application and Performance. Ozonation has been applied
commercially to oxidize cyanides, phenolic chemicals, and organo-
metal complexes. Its applicability to photographic wastewaters
has been studied in the laboratory with good results. Ozone is
used in industrial waste treatment primarily to oxidize cyanide
to cyanate and to oxidize phenols and. dyes to a variety of
colorless nontoxic products.
Oxidation of cyanide to cyanate is illustrated below:
CN- + 03 > CNO- + 02
Continued exposure to ozone will convert the cyanate formed to
carbon dioxide and ammonia; however, this is not economically
practical.
Ozone oxidation of cyanide to cyanate requires 1.8 to 2.0 pounds
ozone per pound of CN-; complete oxidation requires 4.6 to 5.0
pounds ozone per pound of CN-. Zinc, copper, and nickel cyanides
are easily destroyed to a nondetectable level, but cobalt and
iron cyanides are more resistant to ozone treatment.
Advantages and Limitations. Some advantages of ozone oxidation
for handling process effluents are its suitability to automatic
control and on-site generation and the fact that reaction
products are not chlorinated organics and no dissolved solids are
added in the treatment step. Ozone in the presence of activated
carbon, ultraviolet, and other promoters shows promise of
reducing reaction time and improving ozone utilization, but the
process at present is limited by" high capital expense, possible
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chemical interference in the treatment of mixed wastes/ and an
energy requirement of 25 kWh/kg of ozone generated. Cyanide is
not economically oxidized beyond the cyanate form.
Operational Factors. Reliability: Ozone oxidation is highly
reliable with proper monitoring and control, and proper
pretreatment to control interfering substances.
Maintainability: Maintenance consists of periodic removal of
sludge, and periodic renewal of filters and desiccators required
for the input of clean dry air; filter life is a function of
input.concentrations of detrimental constituents.
Solid Waste Aspects: Pretreatment to eliminate substances which
will interfere with the process may be necessary. Dewatering of
sludge generated in the ozone oxidation process or in an "in
line" process may be desirable prior to disposal.
13. Cyanide Oxidation By_ Ozone With UV Radiation
One of the modifications of the ozonation process is the
simultaneous application of ultraviolet light and ozone for the
treatment of wastewater, including treatment of halogenated
organics. The combined action of these two forms produces
reactions by photolysis, photosensitization, hydroxylation,
oxygenation, and oxidation. The process is unique because
several reactions and reaction species are active simultaneously.
Ozonation is facilitated by ultraviolet absorption because both
the ozone and the reactant molecules are raised to a higher
energy state so that they react more rapidly. In addition, free
radicals for use in the reaction are readily hydrolyzed by the
water present. The energy and reaction intermediates created by
the introduction of both ultraviolet and ozone greatly reduce the
amount of ozone required compared with a system using ozone
alone. Figure VII-21 (page 33 7) shows a three-stage UV-ozone
system. A system to treat mixed cyanides requires pretreatment
that involves chemical coagulation, sedimentation, clarification,
equalization, and pH adjustment.
Application and Performance. The ozone-UV radiation process was
developed primarily for cyanide treatment in the electroplating
and color photo-processing areas. It has been successfully
applied to mixed cyanides and organics from organic chemicals
manufacturing processes. The process is particularly useful for
treatment of complexed cyanides such as ferricyanide, copper
cyanide, and nickel cyanide, which are resistant to ozone alone.
14. Cyanide Oxidation By_ Hydrogen Peroxide
Hydrogen peroxide oxidation removes both cyanide and metals in
cyanide containing wastewaters. In this process, cyanide bearing
waters are heated to 49 to 54°C (120 to 130°F) and the pH is
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adjusted to 10.5 to 11.8. Formalin (37 percent formaldehyde) is
added while the tank is vigorously agitated. After 2 to 5
minutes, a proprietary peroxygen compound (41 percent hydrogen
peroxide with a catalyst and additives) is added. After an hour
of mixing, the reaction is complete. The cyanide is converted to
cyanate, and the metals are precipitated as oxides or hydroxides.
The metals are then removed from solution by either settling or
filtration.
The main equipment required for this process is two holding tanks
equipped with heaters and air spargers or mechanical stirrers.
These tanks may be used in a batch or continuous fashion, with
one tank being used for treatment while the other is being
filled. A settling tank or a filter is needed to concentrate the
precipitate.
Application and Performance. The hydrogen peroxide oxidation
process is applicable to cyanide-bearing wastewaters, especially
those containing metal-cyanide complexes. In terms of waste
reduction performance, this process can reduce total cyanide to
less than 0.1 mg/1 and the zinc or cadmium to less than 1.0 mg/1.
Advantages and Limitations. Chemical costs are similar to those
for alkaline chlorination using chlorine and lower than those for
treatment with hypochlorite. All free cyanide reacts and is
completely oxidized to the less toxic cyanate state. In
addition, the metals precipitate and settle quickly, and they may
be recoverable in many instances. However, the process requires
energy expenditures to heat the wastewater prior to treatment.
Demonstration Status. This treatment process was introduced in
1971 and is used in several facilities. No nonferrous metals
manufacturing plants use oxidation by hydrogen peroxide.
15. Evaporation
Evaporation is a concentration process. Water is evaporated from
a solution, increasing the concentration of solute in the
remaining solution. If the resulting water vapor is condensed
back to liquid water, the evaporation-condensation process is
called distillation. However, to be consistent with industry
terminology, evaporation is used in this report to describe both
processes. Both atmospheric and vacuum evaporation are commonly
used in industry today. Specific evaporation techniques are
shown in Figure VII-22 (page 338) and discussed below.
Atmospheric evaporation could be accomplished simply by boiling
the liquid. However, to aid evaporation, heated liquid is
sprayed on an evaporation surface, and air is blown over the
surface and subsequently released to the atmosphere. Thus,
evaporation occurs by humidification of the air stream, similar
to a drying process. Equipment for carrying out atmospheric
evaporation is quite similar for most applications. The major
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element is generally a packed column with an accumulator bottom.
Accumulated wastewater is pumped from the base of the column,
through a heat exchanger, and back into the top of the column,
where it is sprayed into the packing. At the same time, air
drawn upward through the packing by a fan is heated as it
contacts the hot liquid. The liquid partially vaporizes and
humidifies the air stream. The fan then blows the hot, humid air
to the outside atmosphere. A scrubber is often unnecessary
because the packed column itself, acts as a scrubber.
Another form of atmospheric evaporator also works on the air
humidification principle, but the evaporated water is recovered
for reuse by condensation. These air humidification techniques
operate well below the boiling point of water and can utilize
waste process heat to supply the energy required.
In vacuum evaporation, the evaporation pressure is lowered to
cause the liquid to boil at reduced temperature. All of the
water vapor is condensed, and to maintain the vacuum condition,
noncondensible gases (air in particular) are removed by a vacuum
pump. Vacuum evaporation may be either single or double effect.
In double effect evaporation, two evaporators are used, and the
water vapor from the first evaporator (which may be heated by
steam) is used to supply heat to the second evaporator. As it
supplies heat, the water vapor from the first evaporator
condenses. Approximately equal quantities of wastewater are
evaporated in each unit; thus, the double effect system
evaporates twice the amount of water that a single effect system
does, at nearly the same cost in energy but with added capital
cost and complexity. The double effect technique is
thermodynamically possible because the second evaporator is
maintained at lower pressure (higher vacuum) and, therefore,
lower evaporation temperature. Vacuum evaporation equipment may
be classified as submerged tube or climbing film evaporation
units.
Another means of increasing energy efficiency is vapor
recompression evaporation, which enables heat to be transferred
from the condensing water vapor to the evaporating wastewater.
Water vapor generated from incoming wastewaters flows to a vapor
compressor. The compressed steam than travels through the
wastewater via an enclosed tube or coil in which it condenses as
heat is transferred to the surrounding solution. In this way,
the compressed vapor serves as a heating medium. After
condensation, this distillate is drawn off continuously as the
clean water stream. The heat contained in the compressed vapor
is used to heat the wastewater, and energy costs for system
operation are reduced.
In the most commonly used submerged tube evaporator, the heating
and condensing coil are contained in a single vessel to reduce
capital cost. The vacuum in the vessel is maintained by an
eductor-type pump, which creates the required vacuum by the flow
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of the condenser cooling water through a venturi. Wastewater
accumulates in the bottom of the vessel, and it is evaporated by
means of submerged steam coils. The resulting water vapor
condenses as it contacts the condensing coils in the top of the
vessel. The condensate then drips off the condensing coils into
a collection trough that carries it out of the vessel.
Concentrate is removed from the bottom of the vessel.
The major elements of the climbing film evaporator are the
evaporator, separator, condenser, and vacuum pump. Wastewater is
"drawn" into the system by the vacuum so that a constant liquid
level is maintained in the separator. Liquid enters the steam-
jacketed evaporator tubes, and part of it evaporates so that a
mixture of vapor and liquid enters the separator. The design of
the separator is such that the liquid is continuously circulated
from the separator to the evaporator. The vapor entering the
separator flows out through a mesh entrainment separator to the
condenser, where it is condensed as it flows down through the
condenser tubes. The condensate, along with any entrained air,
is pumped out of the bottom of the condenser by a liquid ring
vacuum pump. The liquid seal provided by the condensate keeps
the vacuum in the system from being broken.
Application and Performance. Both atmospheric and vacuum
evaporation are used in many industrial plants, mainly for the
concentration and recovery of process solutions. Many of these
evaporators also recover water for rinsing. Evaporation has also
been applied to recovery of phosphate metal cleaning solutions.
In theory, evaporation should yield a concentrate and a deionized
condensate. Actually, carry-over has resulted in condensate
metal concentrations as high as 10 mg/1, although the usual level
is less than 3 mg/1, pure enough for most final rinses. The
condensate may also contain organic brighteners and antifoaming
agents. These can be removed with an activated carbon bed, if
necessary. Samples from one plant showed 1,900 mg/1 zinc in the
feed, 4,570 mg/1 in the concentrate, and 0.4 mg/1 in the
condensate. Another plant had 416 mg/1 copper in the feed and
21,800 mg/1 in the concentrate. Chromium analysis for that plant
indicated 5,060 mg/1 in the feed and 27,500 mg/1 in the
concentrate. Evaporators are available in a range of capacities,
typically from 15 to 75 gph, and may be used in parallel
arrangements for processing of higher flow rates.
Advantages and Limitations. Advantages of the evaporation
process are that it permits recovery of a wide variety of process
chemicals, and it is often applicable to concentration or removal
of compounds which cannot be accomplished by any other means.
The major disadvantage is that the evaporation process consumes
relatively large amounts of energy for the evaporation of water.
However, the recovery of waste heat from many industrial
processes (e.g., diesel generators, incinerators, boilers and
furnaces) should be considered as a source of this heat for a
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totally integrated evaporation system. Also, in some cases solar
heating could be inexpensively and effectively applied to
evaporation units. Capital costs for vapor compression
evaporators are substantially higher than for other types of
evaporation equipment. However, the energy costs associated with
the operation of a vapor compression evaporator are significantly
lower than costs of other evaproator types. For some
applications, pretreatment may be required to remove solids or
bacteria which tend to cause fouling in the condenser or
evaporator. The buildup of scale on the evaporator surfaces
reduces the heat transfer efficiency and may present a
maintenance problem or increase operating cost. However, it has
been demonstrated that fouling of the heat transfer surfaces can
be avoided or minimized for certain dissolved solids by
maintaining a seed slurry which provides preferential sites for
precipitate deposition. In addition, low temperature differences
in the evaporator will eliminate nucleate boiling and
supersaturation effects. Steam distillable impurities in the
process stream are carried over with the product water and must
be handled by pre-or post treatment.
Operational Factors. Reliability: Proper maintenance will
ensure a high degree of reliability for the system. Without such
attention, rapid fouling or deterioration of vacuum seals may
occur, especially when corrosive liquids are handled.
Maintainability: Operating parameters can be automatically
controlled. Pretreatment may be required, as well as periodic
cleaning of the system. Regular replacement of seals, especially
in a corrosive environment, may be necessary.
Solid Waste Aspects: With only a few exceptions, .the process
does not generate appreciable quantities of solid waste.
Demonstration Status. Evaporation is a fully developed,
commercially available wastewater treatment system. It is used
extensively to recover plating chemicals in the electroplating
industry, and a pilot scale unit has been used in connection with
phosphating of aluminum. Proven performance in silver recovery
indicates that evaporation could be a useful treatment operation
for the photographic industry, as well as for metal finishing.
Vapor compression evaporation has been practically demonstrated
in a number of industries, including chemical manufacturing, food
processing, pulp and paper, and metal working.
16. Flotation
Flotation is the process of causing particles such as metal
hydroxides or oil to float to the surface of a tank where they
can be concentrated and removed. This is accomplished by
releasing gas bubbles which attach to the solid particles,
increasing their buoyancy and causing them to float. In
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principle, this process is the opposite of sedimentation. Figure
VII-23 (page 339) shows one type of flotation system.
Flotation is used primarily in the treatment of wastewater
streams that carry heavy loads of finely divided suspended solids
or oil. Solids having a specific gravity only slightly greater
than 1.0, which would require abnormally long sedimentation
times, may be removed in much less time by flotation. Dissolved
air flotation is of greatest interest in removing oil from water
and is less effective in removing heavier precipitates.
This process may be performed in several ways: foam, dispersed
air, dissolved air, gravity, and vacuum flotation are the most
commonly used techniques. Chemical additives are often used to
enhance the performance of the flotation process.
The principal difference among types of flotation is the method
of generating the minute gas bubbles (usually air) in a
suspension of water and small particles. Chemicals may be used
to improve the efficiency with any of the basic methods. The
following . paragraphs describe the different flotation techniques
and the method of bubble generation for each process.
Froth Flotation - Froth flotation is based on differences in the
physiochemical properties in various particles. Wettability and
surface properties affect, the particles' ability to attach
themselves to gas bubbles in an aqueous medium. In froth
flotation, air is blown through the solution containing flotation
reagents. The particles with water repellant surfaces stick to
air bubbles as they rise and are brought to the surface. A
mineralized froth layer, with mineral particles attached to air
bubbles, is formed. Particles of other minerals which are
readily wetted by water do not stick to air bubbles and remain in
suspension.
Dispersed Air Flotation - In dispersed air flotation, gas bubbles
are generated by introducing the air by means of mechanical
agitation with impellers or by forcing air through porous media.
Dispersed air flotation is used mainly in the metallurgical
industry.
Dissolved Air Flotation - In dissolved air flotation, bubbles are
produced by releasing air from a supersaturated solution under
relatively high pressure. There are two types of contact between
the gas bubbles and particles. The first type is predominant in
the flotation of flocculated materials and involves the
entrapment of rising gas bubbles in the flocculated particles as
they increase in size. The bond between the bubble and particle
is one of physical capture only. The second type of contact is
one of adhesion. Adhesion results from the intermolecular
attraction exerted at the interface between the solid particle
and gaseous bubble.
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Vacuum Flotation - This process consists of saturating the
wastewater with air either directly in an aeration tank, or by
permitting air to enter on the suction of a wastewater pump. A
partial vacuum is applied, which causes the dissolved air to come
out of solution as minute bubbles. The bubbles attach to solid
particles and rise to the surface to form a scum blanket, which
is normally removed by a skimming mechanism. Grit and other
heavy solids that settle to the bottom are generally raked to a
central sludge pump for removal. A typical vacuum flotation unit
consists of a covered cylindrical tank in which a partial vacuum
is maintained. The tank is equipped with scum and sludge removal
mechanisms. The floating material is continuously swept to the
tank periphery, automatically discharged into a scum trough, and
removed from the unit by a pump also under partial vacuum.
Auxiliary equipment includes an aeration tank for saturating the
wastewater with air, a tank with a short retention time for
removal of large bubbles, vacuum pumps, and sludge pumps.
Application and Performance. The primary variables for flotation
design are pressure, feed solids concentration, and retention
period. The suspended solids in the effluent decrease, and the
concentration of solids in the float increases with increasing
retention period. When the flotation process is used primarily
for clarification, a retention period of 20 to 30 minutes usually
is adequate for separation and concentration.
Advantages and Limitations. Some advantages of the flotation
process are the high levels of solids separation achieved in many
applications, the r-elatively low energy requirements, and the
adaptability to meet the treatment requirements of different
waste types. Limitations of flotation are that it often requires
addition of chemicals to enhance process performance and that it
generates large quantities of solid waste.
Operational Factors. Reliability: Flotation systems normally
are very reliable with proper maintenance of the sludge collector
mechanism and the motors and pumps used for aeration.
Maintainability: Routine maintenance is required on the pumps
and motors. The sludge collector mechanism is subject to
possible corrosion or breakage and may require periodic
replacement.
Solid Waste Aspects: Chemicals are commonly used to aid the
flotation process by creating a surface or a structure that can
easily adsorb or entrap air bubbles. Inorganic chemicals, such
as the aluminum and ferric salts, and activated silica, can bind
the particulate matter together and create a structure that can
entrap air bubbles. Various organic chemicals can change the
nature of either the air-liquid interface or the solid-liquid
interface, or both. These compounds usually collect on the
interface to bring about the desired changes. The added
chemicals plus the particles in solution combine to form a large
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volume of sludge which must be further treated or properly
disposed.
Demonstration Status. Flotation is a fully developed process and
is readily available for the treatment of a wide variety of
industrial waste streams. Flotation separation is not
demonstrated in any nonferrous metals manufacturing phase II
plants; it is demonstrated in one primary aluminum (phase I)
plant.
17. Gravity Sludge Thickening
In the gravity thickening process, dilute sludge is fed from a
primary settling tank or clarifier to a thickening tank where
rakes stir the sludge gently to densify it and to push it to a
central collection well. The supernatant is returned to the
primary settling tank. The thickened sludge that collects on the
bottom of the tank is pumped to dewatering equipment or hauled
away. Figure VI1-24 (page 340 ) shows the construction of a
gravity thickener.
Application and Performance. Thickeners are generally used in
facilities where the sludge is to be further dewatered by a
compact mechanical device such as a vacuum filter or centrifuge.
Doubling the solids content in the thickener substantially
reduces capital and operating cost of the subsequent dewatering
device and also reduces cost for hauling. The process is
potentially applicable to almost any industrial plant.
Organic sludges from sedimentation units of one to two percent
solids "concentration can usually be gravity thickened to six to
ten percent; chemical sludges can be thickened to four to six
percent.
Advantages and Limitations. The principal advantage of a gravity
sludge thickening process is that it facilitates further sludge
dewatering. Other advantages are high reliability and minimum
maintenance requirements.
Limitations of the sludge thickening process are its sensitivity
to the flow rate through the thickener and the sludge removal
rate. These rates must be low enough not to disturb the
thickened sludge.
Operational Factors. Reliability: Reliability is high with
proper design and operation. A gravity thickener is designed on
the basis of square feet per pound of solids per day, in which
the required surface area is related to the solids entering and
leaving the unit. Thickener area requirements are also expressed
in terms of mass loading, grams of solids per square meter per
day (Ibs/sq ft/day).
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Maintainability: Twice a year, a thickener must be shut down for
lubrication of the drive mechanisms. Occasionally, water must be
pumped back through the system in order to clear sludge pipes.
Solid Waste Aspects: Thickened sludge from a gravity thickening
process will usually require further dewatering prior to
disposal, incineration, or drying. The clear effluent may be
recirculated in part, or it may be subjected to further treatment
prior to discharge.
Demonstration Status. Gravity sludge thickeners are used
throughout industry to reduce water content to a level where the
sludge may be efficiently handled. Further dewatering is usually
practiced to minimize costs of hauling the sludge to approved
landfill areas.
18. Insoluble Starch Xanthate
Insoluble starch xanthate is essentially an ion exchange medium
used to remove dissolved heavy metals from wastewater. The water
may then either be reused {recovery application) or discharged
(end-of-pipe application). In a commercial electroplating oper-
ation, starch xanthate is coated on a filter medium. Rinse water
containing dragged out heavy metals is circulated through the
filters and then reused for rinsing. The starch-heavy metal
complex is disposed of and replaced periodically. Laboratory
tests indicate that recovery of metals from the complex is
feasible, with regeneration of the starch xanthate. Besides
electroplating, starch xanthate is potentially applicable to any
other .industrial plants where dilute metal wastewater streams are
generated. Its present use is limited to one electroplating
plant.
19. Ion Exchange
Ion exchange is a process in which ions, held by electrostatic
forces to charged functional groups on the surface of the ion
exchange resin, are exchanged for ions of similar charge from the
solution in which the resin is immersed. This is classified as a
sorption process because the exchange occurs on the surface of
the resin, and the exchanging ion must undergo a phase transfer
from solution phase to solid phase. Thus, ionic contaminants in
a waste stream can be exchanged for the harmless ions of the
resin.
Although the precise technique may vary slightly according to the
application involved, a generalized process description follows.
The wastewater stream being treated passes through a filter to
remove any solids, then flows through a cation exchanger which
contains the ion exchange resin. Here, metallic impurities such
as copper, iron, and trivalent chromium are retained. The stream
then passes through the anion exchanger and its associated resin.
Hexavalent chromium, for example, is retained in this stage. If
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one pass does not reduce the contaminant levels sufficiently, the
stream may then enter another series of exchangers. Many ion
exchange systems are equipped with more than one set of
exchangers for this reason.
The other major portion of the ion exchange process concerns the
regeneration of the resin, which now holds those impurities
retained from the waste stream. An ion exchange unit with in-
place regeneration is shown in Figure VII-25 (page 34i ). Metal
ions such as nickel are removed by an acid, cation exchange
resin, which is regenerated with hydrochloric or sulfuric acid,
replacing the metal ion with one or more hydrogen ions. Anions
such as dichromate are removed by a basic, anion exchange resin,
which is regenerated with sodium hydroxide, replacing the anion
with one or more hydroxyl ions. The three principal methods
employed by industry for regenerating the spent resin are:
A) Replacement Service: A regeneration service replaces the
spent resin with regenerated resin, and regenerates the
spent resin at its own facility. The service then has the
problem of treating and disposing of the spent regenerant.
B) In-Place Regeneration: Some establishments may find it less
expensive to do their own regeneration. The spent resin
column is shut down for perhaps an hour, and the spent resin
is regenerated. This results in one or more waste streams
which must be treated in an appropriate manner.
Regeneration is performed as the resins require it, usually
every few months.
C) Cyclic Regeneration: In this process, the regeneration of
the spent resins takes place within the ion exchange unit
itself in alternating cycles with the ion removal process.
A regeneration frequency of twice an hour is typical. This
very short cycle time permits operation with a very small
quantity of resin and with fairly concentrated solutions,
resulting in a very compact system. Again, this process
varies according to application, but the regeneration cycle
generally begins with caustic being pumped through the anion
exchanger, carrying out hexavalent chromium, for example, as
sodium dichromate. The sodium dichromate stream then passes
through a cation exchanger, converting the sodium dichromate
to chromic acid. After concentration by evaporation or
other means, the chromic acid can be returned to the process
line. Meanwhile, the cation exchanger is regenerated with
sulfuric acid, resulting in a waste acid stream containing
the metallic impurities removed earlier. Flushing the
exchangers with water completes the cycle. Thus, the
wastewater is purified and, in this example, chromic acid is
recovered. The ion exchangers, with newly regenerated
resin, then enter the ion removal cycle again.
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Application arid Performance. The list of pollutants for which
the ion exchange system has proved effective includes aluminum,
arsenic, cadmium, chromium (hexavalent and trivalent), copper,
cyanide, gold, iron, lead, manganese, nickel, selenium, silver,
tin, zinc, and more. Thus, it can be applied to a wide variety
of industrial concerns. Because of the heavy concentrations of
metals in their wastewater, the metal finishing industries uti-
lize ion exchange in several ways. As an end-of-pipe treatment,
ion exchange is certainly feasible, but its greatest value is in
recovery applications. It is commonly used as an integrated
treatment to recover rinse water and process chemicals. Some
electroplating facilities use ion exchange to concentrate and
purify plating baths. Also, many industrial concerns, including
a number of nonferrous metals manufacturing plants, use ion
exchange to reduce salt concentrations in incoming water sources.
The ion exchange process may be used to remove cyanide in a
ferrocyanide complex from wastewater. The process generates a
concentrated stream of the complex, which may be treated using
cyanide precipitation.
Ion exchange is applicable to cyanide removal when the cyanide is
complexed with iron. Experimental data have shown that a
specific resin (Rohm & Haas IRA-958) is very selective to the
removal of iron cyanide complexes. The process described below
is based on the use of this resin and upon operating data
obtained from the vendor and from an actual operating ion
exchange facility.
Two downflow columns are used. The columns are operated in a
merry-go-round configuration (see the granular activated carbon
adsorption process description in this section for a discussion
on this type of operation). The regeneration step is carried out
in two stages. The first step uses regeneration solution from
the previous second regeneration step. The second step uses
fresh regeneration solution. This is done because a large
majority of the pollutant ions are eluted in the first step. The
solution used in the second step yields a dilute solution of the
pollutant and can be used in the first step of the next
regeneration cycle. Separation of the regeneration solution in
this manner results in a 50 percent savings in regeneration
solution costs and a more concentrated product. The regeneration
solution used is 15 percent brine (NaCl).
Unless the cyanide in the influent is already in complexed form,
the wastewater must be treated to convert the free cyanide to the
ferrocyanide complex.
The spent brine solution produced in the regeneration step may be
disposed of as a hazardous waste or sent to cyanide
precipitation. In this module the cyanide complex is combined
with more iron at low pH to produce an insoluble complex.
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The equipment recommended for the ion exchange process and the
applicable design parameters and assumptions are detailed below:
Ion exchange is highly efficient at recovering metal bearing
solutions. Recovery of chromium, nickel, phosphate solution, and
sulfuric acid from anodizing is commercial. A chromic acid
recovery efficiency of 99.5 percent has been demonstrated.
Typical data for purification of rinse water have been reported
and are displayed in Table VI1-25. Sampling at one nonferrous
metals manufacturing plant characterized influent and effluent
streams for an ion exchange unit on a silver bearing waste. This
system was in start-up at the time of sampling, however, and was
not found to be operating effectively.
Advantages and Limitations. Ion exchange is a versatile
technology applicable to a great many situations. This
flexibility, along with -its compact nature and performance, makes
ion exchange a very effective method of wastewater treatment.
However, the resins in these systems can prove to be a limiting
factor. The thermal limits of the anion resins, generally in the
vicinity of 60°C, could prevent its use in certain situations.
Similarly, nitric acid, chromic acid, and hydrogen peroxide can
all damage the resins, as will iron, manganese, and copper when
present with sufficient concentrations of dissolved oxygen.
Removal of a particular trace contaminant may be uneconomical
because of the presence of other ionic species that are preferen-
tially removed. The regeneration of the resins presents its own
problems. The cost of the regenerative chemicals can be high.
In addition, the waste streams originating from the regeneration
process are extremely high in pollutant concentrations, although
low in volume. These must be further processed for proper
disposal.
Operational Factors. Reliability: With the exception of
occasional clogging or fouling of the resins, ion exchange has
proved to be a highly dependable technology.
Maintainability: Only the normal maintenance of pumps, valves,
piping and other hardware used in the regeneration process is
required.
Solid Waste Aspects: Few, if any, solids accumulate within the
ion exchangers, and those which do appear are removed by the re-
generation process. Proper prior treatment and planning can eli-
minate solid buildup problems altogether. The brine resulting
from regeneration of the ion exchange resin must usually be
treated to remove metals before discharge. This can generate
solid waste.
Demonstration Status. All of the applications mentioned in this
document are available for commercial use, and industry sources
estimate the number of units currently in the field at well over
120. The research and development in ion exchange is focusing on
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improving the quality and efficiency of the resins, rather than
new applications. Work is also being done on a continuous
regeneration process whereby the resins are contained on a fluid-
transfusible belt. The belt passes through a compartmentalized
tank with ion exchange, washing, and regeneration sections. The
resins are therefore continually used and regenerated. No such
system, however, has been reported beyond the pilot stage.
Ion exchange has been used to treat cyanide containing wastewater
at two plants for the primary aluminum subcategory (nonferrous
metals manufacturing phase I).
20. Membrane Filtration
Membrane filtration is a treatment system for removing
precipitated metals from a wastewater stream. It must therefore
be preceded by those treatment techniques which will properly
prepare the wastewater for solids removal. Typically, a membrane
filtration unit is preceded by pH adjustment or sulfide addition
for precipitation of the metals. These steps are followed by the
addition of a proprietary chemical reagent which causes the
precipitate to be non-gelatinous, easily dewatered, and highly
stable. The resulting mixture of pretreated wastewater and
reagent is continuously recirculated through a filter module and
back into a recirculation tank. The filter module contains
tubular membranes. While the reagent-metal hydroxide precipitate
mixture flows through the inside of the tubes, the water and any
dissolved salts permeate the membrane. When the recirculating
slurry reaches a concentration of 10 to 15 percent solids, it is
pumped out of the system as sludge.
Application and Performance. Membrane filtration appears to be
applicable to any wastewater or process water containing metal
ions which can be precipitated using hydroxide, sulfide or
carbonate precipitation. It could function as the primary
treatment system, but also might find application as a polishing
treatment (after precipitation and settling) to ensure continued
compliance with metals limitations. Membrane filtration systems
are being used in a number of industrial applications,
particularly in the metal finishing area. They have also been
used for toxic metals removal in the metal fabrication industry
and the paper industry.
The permeate is claimed by one manufacturer to contain less than
the effluent concentrations shown in the following table,
regardless of the influent concentrations. These claims have
been largely substantiated by the analysis of water samples at
various plants in various industries.
In the performance predictions for this technology, pollutant
concentrations are reduced to the levels shown below in Table
VII-26 (page 316) unless lower levels are present in the influent
stream.
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Advantages and Limitations. A major advantage of the membrane
filtration system is that installations can use most of the
conventional end-of-pipe systems that may already be in place.
Removal efficiencies are claimed to be excellent, even with
sudden variation of pollutant input rates; however, the
effectiveness of the membrane filtration system can be limited by
clogging of the filters. Because pH changes in the waste stream
greatly intensify clogging problems, the pH must be carefully
monitored and controlled. Clogging can force the shutdown of the
system and may interfere with production. In addition, the
relatively high capital cost of this system may limit its
Operational Factors. Reliability: Membrane filtration has been
shown to be a very reliable system, provided that the pH is
strictly controlled. Improper pH can result in the clogging of
the membrane. Also, surges in the flow rate of the waste stream
must be controlled in order to prevent solids from passing
through the filter and into the effluent.
Maintainability: The membrane filters must be regularly
monitored, and cleaned or replaced as necessary. Depending on
the composition of the waste stream and its flow rate, frequent
cleaning of the filters may be required. Flushing with
hydrochloric acid for 6 to 24 hours will usually suffice. In
addition, the routine maintenance of pumps, valves, and other
plumbing is required.
Solid Waste Aspects: When the recirculating reagent-precipitate
slurry reaches 10 to 15 percent solids, it is pumped out of the.
system". It can then be disposed of directly or it can undergo a
dewatering process. Because this sludge contains toxic metals,
it requires proper disposal.
Demonstration Status. There are more than 25 membrane filtration
systems presently in use on metal finishing and similar
wastewaters. Bench scale and pilot studies are being run in an
attempt to expand the list of pollutants for which this system is
known to be effective.
21 . Peat Adsorption
Peat moss is a complex natural organic material containing lignin
and cellulose as major constituents. These constituents,
particularly lignin, bear polar functional groups, such as
alcohols, aldehydes, ketones, acids, phenolic hydroxides, and
ethers, that can be involved in chemical bonding. Because of the
polar nature of the material, its adsorption of dissolved solids
such as transition metals and polar organic molecules is quite
high. These properties have led to the use of peal as an agent
for the purification of industrial wastewater.
Peat adsorption is a "polishing" process which can achieve very
low effluent concentrations for several pollutants. If the
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concentrations of pollutants are above 10 mg/1, then peat
adsorption must be preceded by pH adjustment for metals
precipitation and subsequent clarification. Pretreatment is also
required for chromium wastes using ferric chloride and sodium
sulfide. The wastewater is then pumped into a large metal
chamber called a kier which contains a layer of peat through
which the waste stream passes. The water flows to a second kier
for further adsorption. The wastewater is then ready for
discharge. This system may be automated or manually operated.
Application and Performance. Peat adsorption can be used in
nonferrous metals manufacturing for removal of residual dissolved
metals from clarifier effluent. Peat moss may be used to treat
wastewaters containing heavy metals such as mercury, cadmium,
zinc, copper, iron, nickel, chromium, and lead, as well as
organic matter such as oil, detergents, and dyes. Peat
adsorption is currently used commercially at a textile plant, a
newsprint facility, and a metal reclamation operation.
Table VII-27 (page 316 ) contains performance figures obtained
from pilot plant studies. Peat adsorption was preceded by pH
adjustment for precipitation and by clarification.
In addition, pilot plant studies have shown that chelated metal
wastes, as well as the chelating agents themselves, are removed
by contact with peat moss.
Advantages and Limitations. The major advantages of the system
include its ability to yield low pollutant concentrations, its
broad scope in terms of the pollutants eliminated, and its
capacity to accept wide variations of waste water composition.
Limitations include the cost of purchasing, storing, and
disposing of the peat moss; the necessity for regular replacement
of the peat may lead to high operation and maintenance costs.
Also, the pH adjustment must be altered according to the
composition of the waste stream.
Operational Factors. Reliability: The question of long term
reliability is not yet fully answered. Although the manufacturer
reports it to be a highly reliable system, operating experience
is needed to verify the claim.
Maintainability: The peat moss used in this process soon
exhausts its capacity to adsorb pollutants. At that time, the
kiers must be opened, the peat removed, and fresh peat placed
inside. Although this procedure is easily and quickly
accomplished, it must be done at regular intervals, or the
system's efficiency drops drastically.
Solid Waste Aspects: After removal from the kier, the spent peat
must be eliminated. If incineration is used, precautions should
be taken to insure that those pollutants removed from the water
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are not released again in the combustion process. Presence of
sulfides in the spent peat, for example, will give rise to sulfur
dioxide in the fumes from burning. The presence of significant
quantities of toxic heavy metals in nonferrous metals
manufacturing wastewater will in general preclude incineration of
peat used in treating these wastes.
Demonstration Status. Only three facilities currently use
commercial adsorption systems in the United States - a textile
manufacturer, a newsprint facility, and a metal reclamation firm.
No data have been reported showing the use of peat adsorption in
nonferrous metals manufacturing plants.
22. Reverse Osmosis
The process of osmosis involves the passage of a liquid through a
semipermeable membrane from a dilute to a more concentrated
solution. Reverse osmosis (RO) is an operation in which pressure
is applied to the more concentrated solution, forcing the per-
meate to diffuse through the membrane and into the more dilute
solution. This filtering action produces a concentrate and a
permeate on opposite sides of the membrane. The concentrate can
then be further treated or returned to the original operation for
continued use, while the permeate water can be recycled for use
as clean water. Figure VII-26 (page 342 ) depicts a reverse
osmosis system.
As illustrated in Figure VII-27, (page 343), there are three
basic configurations used in commercially available RO modules:
tubular, spiral-wound, and hollow fiber. All of these operate on
the principle described above, the major difference being their
mechanical and structural design characteristics.
The tubular membrane module uses a porous tube with a cellulose
acetate membrane lining. A common tubular module consists of a
length of 2.5 cm (1 inch) diameter tube wound on a supporting
spool and encased in a plastic shroud. Feed water is driven into
the tube under pressures varying from 40 to 55 atm (600-800 psi).
The permeate passes through the walls of the tube and is
collected in a manifold while the concentrate is drained off at
the end of the tube. A less widely used tubular RO module uses a
straight tube contained in a housing, under the same operating
conditions.
Spiral-wound membranes consist of a porous backing sandwiched
between two cellulose acetate membrane sheets and bonded along
three edges. The fourth edge of the composite sheet is attached
to a large permeate collector tube. A spacer screen is then
placed on top of the membrane sandwich, and the entire stack is
rolled around the centrally located tubular permeate collector.
The rolled up package is inserted into a pipe able to withstand
the high operating pressures employed in this process, up to 55
atm (800 psi) with the spiral-wound module. When the system is
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operating, the pressurized product water permeates the membrane
and flows through the backing material to the central collector
tube. The concentrate is drained off at the end of the container
pipe and can be reprocessed or sent to further treatment facili-
ties.
The hollow fiber membrane configuration is made up of a bundle of
polyamide fibers of approximately 0.0075 cm (0.003 in.) OD and
0.0043 cm (0.0017 in.) ID. A commonly used hollow fiber module
contains several hundred thousand of the fibers placed in a long
tube, wrapped around a flow screen, and rolled into a spiral.
The fibers are bent in a U-shape and their ends are supported by
an epoxy bond. The hollow fiber unit is operated under 27 atm
(400 psi), the feed water being dispersed from the center of the
module through a porous distributor tube. Permeate flows through
the membrane to the hollow interiors of the fibers and is
collected at the ends of the fibers.
The hollow fiber and spiral-wound modules have a distinct advan-
tage over the tubular system in that they are able to load a very
large membrane surface area into a relatively small volume.
However, these two membrane types are much more susceptible to
fouling than the tubular system, which has a larger flow channel.
This characteristic also makes the tubular membrane much easier
to clean and regenerate than either the spiral-wound or hollow
fiber modules. One manufacturer claims that its helical tubular
module can be physically wiped clean by passing a soft porous
polyurethane plug under pressure-through the module.
Application and Performance. In a number of metal processing
plants, the overflow from the first rinse in a countercurrent
setup is directed to a reverse osmosis unit, where it is
separated.into two streams. The concentrated stream contains
dragged out chemicals and is returned to the bath to replace the
loss of solution caused by evaporation and dragout. The dilute
stream (the permeate) is routed to the last rinse tank to provide
water for the rinsing operation. The rinse flows from the last
tank to the first tank, and the cycle is complete.
The closed-loop system described above may be supplemented by the
addition of a vacuum evaporator after the RO unit in order to
further reduce the volume of reverse osmosis concentrate. The
evaporated vapor can be condensed and returned to the last rinse
tank or sent on for further treatment.
The largest application has been for the recovery of nickel solu-
tions. It has been shown that RO can generally be applied to
most acid metal baths with a high degree of performance,
providing that the membrane unit is not overtaxed. The
limitations most critical here are the allowable pH range and
maximum operating pressure for each particular configuration.
Adequate prefiltration is also essential. Only three membrane
types are readily available in commercial RO units, and their
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overwhelming use has been for the recovery of various acid metal
baths. For the purpose of calculating performance predictions of
this technology, a rejection ratio of 98 percent is assumed for
dissolved salts, with 95 percent permeate recovery.
Advantages and Limitations. The major advantage of reverse
osmosis for handling process effluents is its ability to
concentrate dilute solutions for recovery of salts and chemicals
with low power requirements. No latent heat of vaporization or
fusion is required for effecting separations; the main energy
requirement is for a high pressure pump. It requires relatively
little floor space for compact, high capacity units, and it
exhibits good recovery and rejection rates for a number of
typical process solutions. A limitation of the reverse osmosis
process for treatment of process effluents is its limited
temperature range for satisfactory operation. For cellulose
acetate systems, the preferred limits are 18° to 30°C (65° to
85°F); higher temperatures will increase the rate of membrane
hydrolysis and reduce system life, while lower temperatures will
result in decreased fluxes with no damage to the membrane.
Another limitation is inability to handle certain solutions.
Strong oxidizing agents, strongly acidic or basic solutions,
solvents, and other organic compounds can cause dissolution of
the membrane. Poor rejection of some compounds such as borates
and low molecular weight organics is another problem. Fouling of
membranes by slightly soluble components in solution or colloids
has caused failures, and fouling of membranes by feed waters with
high levels of suspended solids can be a problem. A final limi-
tation is inability to treat or achieve high concentration with
some solutions. Some concentrated solutions may have initial os-
motic pressures which are so high that they either exceed avail-
able operating pressures or are uneconomical to treat.
Operational Factors. Reliability: Very good reliability is
achieved so long as the proper precautions are taken to minimize
the chances of fouling or degrading the membrane. Sufficient
testing of the waste stream prior to application of an RO system
will provide the information needed to insure a successful
application.
Maintainability: Membrane life is estimated to range from six
months to three years, depending on the use of the system.
Downtime for flushing or cleaning is on the order of two hours as
often as once each week; a substantial portion of maintenance
time must be spent on cleaning any prefilters installed ahead of
the reverse osmosis unit.
Solid Waste Aspects: In a closed loop system utilizing RO there
is a constant recycle of concentrate and a minimal amount of
solid waste. Prefiltration eliminates many solids before they
reach the module and helps keep the buildup to a minimum. These
solids require proper disposal.
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Demonstration Status. There are presently at least one hundred
reverse osmosis wastewater applications in a variety of
industries. In addition to these, there are 30 to 40 units being
used to provide pure process water for several industries.
Despite the many types and configurations of membranes, only the
spiral-wound cellulose acetate membrane has had widespread suc-
cess in commercial applications.
23. Sludge Bed Drying
~As a waste treatment procedure, sludge bed drying is employed to
reduce the water content of a variety of sludges to the point
where they are amenable to mechanical collection and removal to
landfill. These beds usually consist of 15 to 45 cm (6 to 18
in.) of sand over a 30 cm (12 in.) deep gravel drain system made
up of 3 to 6 mm (1/8 to 1/4 in.) graded gravel overlying drain
tiles. Figure VI1-28 (page 344) shows the construction of a
drying bed.
Drying beds are usually divided into sectional areas
approximately 7.5 meters (25 ft) wide x 30 to 60 meters (100 to
200 ft) long. The partitions may be earth embankments, but more
often are made of planks and supporting grooved posts.
To apply liquid sludge to the sand bed, a closed conduit or a
pressure pipeline with valved outlets at each sand bed section is
often employed. Another method of application is by means of an
open channel with appropriately placed side openings which are
controlled by slide gates. With either type of delivery system,
a concrete splash slab should be provided to receive the falling
sludge and prevent erosion of the sand surface.
Where it is necessary to dewater sludge continuously throughout
the year regardless of the weather, sludge beds may be covered
with a fiberglass reinforced plastic or other roof. Covered
drying beds permit a greater volume of sludge drying per year in
most climates because of the protection afforded from rain or
snow and because of more efficient control of temperature,.
Depending on the climate, a combination of open and enclosed beds
will provide maximum utilization of the sludge bed drying
facilities.
Application and Performance. Sludge drying beds are a means of
dewatering sludge from clarifiers and thickeners. They are
widely used both in municipal and industrial treatment
facilities.
Dewatering of sludge on sand beds occurs by two mechanisms:
filtration of water through the bed and evaporation of water as a
result of radiation and convection. Filtration is generally
complete in one to two days and may result in solids
concentrations as high as 15 to 20 percent. The rate of
filtration depends on the drainability of the sludge.
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The rate of air drying of sludge is related to temperature,
relative humidity, and air velocity. Evaporation will proceed at
a constant rate to a critical moisture content, then at a falling
rate to an equilibrium moisture content. The average evaporation
rate for a sludge is about 75 percent of that from a free water
surface.
Advantages and Limitations. The main advantage of sludge drying
beds over other types of sludge dewatering is the relatively low
cost of construction, operation, and maintenance.
Its disadvantages are the large area of land required and long
drying times that depend, to a 'great extent, on climate and
weather.
Operational Factors. Reliability: Reliability is high with
favorable climactic conditions, proper bed design and care to
avoid excessive or unequal sludge application. If climatic
conditions in a given area are not favorable for adequate drying,
a cover may be necessary.
Maintainability: Maintenance consists basically of periodic
removal of the dried sludge. Sand removed from the drying bed
with the sludge must be replaced and the sand layer resurfaced.
The resurfacing of sludge beds is the major expense item in
sludge bed maintenance, but there are other areas which may
require attention. Underdrains occasionally become clogged and
have to be cleaned. Valves or sludge gates that control the flow
of sludge to the beds must be kept watertight. Provision for
drainage of lines in winter should be provided to prevent damage
from freezing. The partitions between beds should be tight so
that sludge will not flow from one compartment to another. The
outer walls or banks around the beds should also be watertight.
Solid Waste Aspects: The full sludge drying bed must either be
abandoned or the collected solids must be removed to a landfill.
These solids contain whatever metals or other materials were
settled in the clarifier. Metals will be present as hydroxides,
oxides, sulfides, or other salts. They have the potential for
leaching and contaminating ground water, whatever the location of
the semidried solids. Thus the abandoned bed or landfill should
include provision for runoff control and leachate monitoring.
Demonstration Status. Sludge beds have been in common use in
both municipal and industrial facilities for many years.
However, protection of ground water from contamination is not
always adequate.
24. Ultrafiltration
Ultrafiltration (UF) is a process which uses semipermeable
polymeric membranes to separate emulsified or colloidal materials
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suspended in a liquid phase by pressurizing the liquid so that it
permeates the membrane. The membrane of an ultrafilter forms a
molecular screen which retains molecular particles based on their
differences in size, shape, and chemical structure. The membrane
permits passage of solvents and lower molecular weight molecules.
At present, an ultrafilter is capable of removing materials with
molecular weights in the range of 1,000 to 100,000 and particles
of comparable or larger sizes.
In an ultrafiltration process, the feed solution is pumped
through a tubular membrane unit. Water and some low molecular
weight materials pass through the membrane under the applied
pressure of 2 to 8 atm (10 to 100 psiq). Emulsified oil droplets
and suspended particles are retained, concentrated, and removed
continuously. In contrast to ordinary filtration, retained
materials are washed off the membrane filter rather than held by
it. Figure VII-29 (page 345 ) represents the ultrafiltration
process.
Application and Performance. Ultrafiltration has potential
application to nonferrous metals manufacturing for separation of
oils and residual solids from a variety of waste streams. In
treating nonferrous metals manufacturing wastewater, its greatest
applicability would be as a polishing treatment to remove
residual precipitated metals after chemical precipitation and
clarification. Successful commercial use, however, has been
primarily for separation of emulsified oils from wastewater.
Over one hundred such units now operate in the United States,
treating emulsified oils from a variety of industrial processes.
Capacities of currently operating units range from a few hundred
gallons a week to 50,000 gallons per day. Concentration of oily
emulsions to 60 percent oil or more is possible. Oil
concentrates of 40 percent or more are generally suitable for
incineration, and the permeate can be treated further and in some
cases recycled back to the process. In this way, it is possible
to eliminate contractor removal costs for oil from some oily
waste streams.
The test data in Table VII-28 (page 3^5) indicate ultrafiltration
performance (note that UF is not istended to remove dissolved
solids).
The removal percentages shown are typical, but they can be
influenced by pH and other conditions.
The permeate or effluent from the ultrafiltration unit is
normally of a quality that can be reused in industrial
applications or discharged directly. The concentrate from the
ultrafiltration unit can be disposed of as any oily or solid
waste.
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Advantages and Limitations. Ultrafiltration is sometimes an
attractive alternative to chemical treatment because of lower
capital equipment, installation, and operating costs, very high
oil and suspended solids removal, and little required
pretreatment. It places a positive barrier between pollutants
and effluent which reduces the possibility of extensive pollutant
discharge due to operator error or upset in settling and skimming
systems. Alkaline values in alkaline cleaning solutions can be
recovered and reused in process.
A limitation of ultrafiltration for treatment of process
effluents is its narrow temperature range (18° to 30°C) for
satisfactory operation. Membrane life decreases with higher
temperatures, but flux increases at elevated temperatures.
Therefore, surface area requirements are a function of
temperature and become a tradeoff between initial costs and
replacement costs for the membrane. In addition, ultrafiltration
cannot handle certain solutions. Strong oxidizing agents,
solvents, and other organic compounds can dissolve the membrane.
Fouling is sometimes a problem, although the high velocity of the
wastewater normally creates enough turbulence to keep fouling at
a minimum. Large solids particles can sometimes puncture the
membrane and must be removed by gravity settling or filtration
prior to the ultrafiltration unit.
Operational Factors. Reliability: The reliability of an
ultrafiltration system is dependent on the proper filtration,
settling or other treatment of incoming waste streams to prevent
damage to the membrane. Careful pilot studies should be done in
each instance to determine necessary pretreatment steps and the
exact membrane type to be used.
Maintainability: A limited amount of regular maintenance is
quired for the pumping system. In addition, membranes must be
periodically changed. Maintenance associated with membrane plug-
ging can be reduced by selection of a membrane with optimum phy-
sical characteristics and sufficient velocity of the waste
stream. It is occasionally necessary to pass a detergent
solution through the system to remove an oil and grease film
which accumulates on the membrane. With proper maintenance,
membrane life can be greater than twelve months.
Solid Waste Aspects: Ultrafiltration is used primarily to
recover solids and liquids. It therefore eliminates solid waste
problems when the solids (e.g., paint solids) can be recycled to
the process. Otherwise, the stream containing solids must be
treated by end-of-pipe equipment. In the most probable
applications within the nonferrous metals manufacturing category,
the ultrafilter would remove hydroxides or sulfides of metals
which have recovery value.
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Demonstrat ion Status. The ultrafiltration process is well
developed and commercially available for treatment of wastewater
or recovery of certain high molecular weight liquid and solid
contaminants.
25. Vacuum Filtration
In wastewater treatment plants, sludge dewatering by vacuum
filtration generally uses cylindrical drum filters. These drums
have a filter medium which may be cloth made of natural or
synthetic fibers or a wire-mesh fabric. The drum is suspended
above and dips into a vat of sludge. As the drum rotates slowly,
part of its circumference is subject to an internal vacuum that
draws sludge to the filter medium. Water is drawn through the
porous filter cake to a discharge port, and the dewatered sludge,
loosened by compressed air, is scraped from the filter mesh.
Because the dewatering of sludge on vacuum filters is relativley
expensive per kilogram of water removed, the liquid sludge is
frequently thickened prior to processing. A vacuum filter is
shown in Figure VII-30 (page 346).
Application and Performance. Vacuum filters are frequently used
both in municipal treatment plants and in a wide variety of
industries. They are most commonly used in larger, facilities,
which may have a thickener to double the solids content of
clarifier sludge before vacuum filtering.
The function of vacuum filtration is to reduce the water content
of sludge, so that the solids content increases from about 5
percent to about 30 percent.
Advantages and Limitations. Although the initial cost and area
requirement of the vacuum filtration system are higher than those
of a centrifuge, the operating cost is lower, and no special
provisions for sound and vibration protection need be made. The
dewatered sludge from this process is in the form of a moist cake
and can be conveniently handled.
Operational Factors. Reliability: Vacuum filter systems have
proven reliable at many industrial and municipal treatment
facilities. At present, the largest municipal installation is at
the West Southwest wastewater treatment plant of Chicago,
Illinois, where 96 large filters were installed in 1925,
functioned approximately 25 years, and then were replaced with
larger units. Original vacuum filters at Minneapolis-St. Paul,
Minnesota, now have over 28 years of continuous service, and
Chicago has some units with similar or greater service life.
Maintainability: Maintenance consists of the cleaning or
replacement of the filter media, drainage grids, drainage piping,
filter pans, and other parts of the equipment. Experience in a
number of vacuum filter plants indicates that maintenance
consumes approximately 5 to 15 percent of the total time. If
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carbonate buildup or other problems are unusually severe,
maintenance time may be as high as 20 percent. For this reason,
it is desirable to maintain one or more spare units.
If intermittent operation is used, the filter equipment should be
drained and washed each time it is taken out of service. An
allowance for this wash time must be made in filtering schedules.
Solid Waste Aspects: Vacuum filters generate a solid cake which
is usually trucked directly to landfill". All of the metals
extracted from the plant wastewater are concentrated in the
filter cake as hydroxides, oxides, sulfides, or other salts.
Demonstration Status. Vacuum filtration has been widely used for
many years. It is a fully proven, conventional technology for
sludge dewatering. Vacuum filtration is used in 20 nonferrous
metals'manufacturing plants for sludge dewatering.
26. Permanganate Oxidation
Permanganate oxidation is a chemical reaction by which wastewater
pollutants can be oxidized. When the reaction is carried to
completion, the byproducts of the oxidation are not
environmentally harmful. A large number of pollutants can be
practically oxidized by permanganate, including cyanides,
hydrogen sulfide, and phenol. In addition, the chemical oxygne
demand (COD) and many odors in wastewaters and sludges can be
significantly reduced by permanganate oxidation carried to its
end point. Potassium permanganate can be added to wastewater in
either dry or slurry form. The oxidation occurs optimally in the
8 to 9 pH range. As an example of the permanganate oxidation
process, the following chemical equation shows the oxidation of
phenol by potassium permanganate:
3 C«HS(OH) + 28KMn04 + 5H2 > 18 C02 + 28KOH + 28 Mn02.
One of the byproducts of this oxidation is manganese dioxide
(Mn02), which occurs as a relatively stable hydrous colloid
usually having a negative charge. These properties, in addition
to its large surface area/ enable manganese dioxide to act as a
sorbent for metal cation, thus enhancing their removal from the
wastewater.
Application and Performance. Commercial use of permanganate
oxidation has been primarily for the control of phenol and waste
odors. Several municipal waste treatment facilities report that
initial hydrogen sulfide concentrations (causing serious odor
problems) as high as 100 mg/1 have been reduced to zero through
the application of potassium permanganate. A variety of
industries (including metal finishers and agricultural chemical
manufacturers) have used permanganate oxidiation to totally
destroy phenol in their wastewaters.
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Advantages and Limitations. Permanganate oxidation has several
advantages as a wastewater treatment technique. Handling and
storage are facilitated by its non-toxic and non-corrosive
nature. Performance has been proved in a number of municipal and
industrial applications. The tendency of the manganese dioxide
by-product to act as a coagulant aid is a distinct advantage over
other types of chemical treatment.
The cost of permanganate oxidation treatment can be limiting
where very large dosages are required to oxidize wastewater
pollutants. In addition, care must be taken in storage to
prevent exposure to intense heat, acids, or reducing agents;
exposure could create a fire hazard or cause explosions. Of
greatest concern is the environmental hazard which the use of
manganese chemicals in treatment could cause. Care must be taken
to remove the manganese from treated water before discharge.
Operational Factors. Reliability: Maintenance consists of
periodic sludge removal and cleaning of pump feed lines.
Frequency of maintenance is dependent on wastewater
characteristics.
Solid Waste Aspects? Sludge is generated by the process where
the manganese dioxide byproduct tends to act as a coagulant aid.
The sludge from permanganate oxidation can be collected and
handled by standard sludge treatment and processing equipment.
No nonferrous metals manufacturing facilities are known to use
permanganate oxidation for wastewater treatment at this time.
Demonstration Status. The oxidiation of wastewater pollutants by
potassium permanganate is a proven treatment process in several
types of industries. It has been shown effective in treating a
wide variety of pollutants in both municipal and industrial
wastes.
Activated Alumina Adsorption
Application, Performance, Advantages and Limitations. Activated
alumina adsorbs arsenic and fluorides. Alumina's removal
efficiency depends on the wastewater characteristics. High
concentrations of alkalinity or chloride and high pH reduce
activated alumina's capacity to adsorb. This reduction in
adsorptive capacity is due to the alkalinity-causing (e.g.,
hydroxides, carbonates, etc.) and chlorine anions competing with
arsenic and fjuoride ions for removal sites on the alumina.
While chemical precipitation (as discussed on p. 214 ) can reduce
fluoride to less than 14 mg/1 by formation of calcium fluoride,
activated alumina can reduce fluoride levels to below 1.0 mg/1 on
a long-term basis. An initial concentration of 30 mg/1 of
fluoride can be reduced by as much as 85 to 99+ percent.
Influent arsenic concentrations of 0.3 to 10 mg/1 can be reduced
by 85 to 99+ percent. However, some complex forms of fluoride
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are not removed by activated alumina. Caustic, sulfuric acid,
hydrochloric acid, and alum are used to chemically regenerate
activated alumina.
Operational Factors—Reliability and Maintainability: Activated
alumina has been used at potable water treatmwnt plants for many
years. Furthermore, the equipment is similar to that found in
ion-exchange water softening plants which are commonly used in
industry to prepare boiler water.
Demonstration Status. The use of activated" alumina has not been
reported by any nonferrous metals manufacturing plants nor is it
widely applied in any other industrial categories. High capital
and operation costs generally limit the wide application of this
process in industrial applications.
Ammonia Steam Stripping
Ammonia, often used as a process reagent, dissolves in water to
an extent governed by the partial pressure of the gas in contact
with the liquid. The ammonia may be removed from process
wastewaters by stripping with air or steam.
Air stripping takes place in a packed or lattice tower; air is
blown through the packed bed or lattice, over which the
ammonia-laden stream flows. Usually, the wastewater is heated
prior to delivery to the tower, and air is used at ambient
temperature.
The term "ammonia steam stripping" refers to the process of
desorbing aqueous ammonia by contacting the liquid with a
sufficient amount of ammonia-free steam. The steam is introduced
countercurrent to the wastewater to maximize removal of ammonia.
The operation is commonly carried out in packed bed or tray
columns, and the pH is adjusted to 12 or more with lime. Simple
tray designs (such as dish and doughnut trays) are used in steam
stripping because of the presence of appreciable suspended solids
and the scaling produced by lime. These allow easy cleaning of
the tower, at the expense of somewhat lower steam water contact
efficiency, necessitating the use of more trays for the same
removal efficiency.
Application and Performance. The evaporation of water and the
volatilization of ammonia generally produces a drop in both
temperature and pH, which ultimately limit the removal of ammonia
in a single air stripping tower. However, high removals are
favored by:
1. High pH values, which shift the equilibrium from ammonium
toward free ammonia;
2. High temperature, which decreases the solubility of ammonia
in aqueous solutions; and
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3. Intimate and extended contact between the wastewater to be
stripped and the stripping gas.
Of these factors, pH and temperature are generally more
cost-effective to optimize than increasing contact time by an
increase in contact tank volume or recirculation ratio. The
temperature will, to some extent, be controlled by the climatic
conditions; the pH of the wastewater can be adjusted to assure
optimum stripping.
Steam stripping offers better ammonia removal (99 percent or
better) than air stripping for high-ammonia wastewaters found in
the primary molybdenum and rhenium, secondary molybdenum and
vanadium, primary nickel and cobalt, secondary precious metals,
primary and secondary tin, secondary tungsten and cobalt,
secondary uranium and primary zirconium and hafnium subcategories
of this category. The performance of an ammonia stripping column
is influenced by a number of important variables that are
associated with the wastewater being treated and column design.
Brief discussions of these variables follow.
Wastewater pH: Ammonia in water exists in two forms, NH3 and
HN4+, the distribution of which is pH dependent. Since only the
molecular form of ammonia (NH3) can be stripped, increasing the
fraction of NH3 by increasing the pH enhances the rate of ammonia
desorption.
Column Temperature: The temperature of the stripping column
affects the equilibrium between gaseous and dissolved ammonia, as
well as the equilibrium between the molecular and ionized forms
of ammonia in water. An increase in the temperature reduces the
ammonia solubility and increases the fraction of aqueous ammonia
that is in the molecular form, both exhibiting favorable effects
on the desorption rate.
Steam rate: The rate of ammonia transfer from the liquid to gas
phase is directly proportional to the degree of ammonia
undersaturation in the desorbing gas. Increasing the fate of
steam supply, therefore, increases undersaturation and ammonia
transfer.
Column design: A properly designed stripper column achieves
uniform distribution of the feed liquid across the cross section
of the column, rapid renewal of the liquid-gas interface, and
extended liquid-gas contacting area and time.
Chemical analysis data were collected fo raw waste (treatment
influent) and treated waste (treatment effluent) from one plant
of the iron and steel manufacturing category. EPA 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
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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.
An arithmetic mean of the treatment effluent data produced an
ammonia long-term mean value of 32.2 mg/1. The one-day maximum,
10-day and 30-day average concentrations attainable by ammonia
steam stripping were calcualted using the long-term mean of the
32.2 .mg/1 and the variability factors developed for the combined
metals data base. This produced ammonia concentrations of 133.3,
58.6, and 52.1 mg/1 ammonia for the one-day maximum, 10-day and
30-day averages, respectively.
As discussed below, steam stripping is demonstrated within the
nonferrous metals manufacturing category. EPA believes the
performance data from the iron and steel manufacturing category
provide a valid measure of this technology's performance on
nonferrous category wastewater.
The Agency has verified the steam stripping performance values
using a steam stripping data collected at a zirconium-hafmium
plant, a plant in the nonferrous category (phase II). Data
collected by the plant represent almost two years of daily
operations, and support the long-term mean used to establish
treatment effectiveness.
Steam stripping can recover significant quantities of reagent
ammonia from wastewaters containing extremely high initial
ammonia concentrations, which partially offsets the capital and
energy costs of the technology.
Advantages and Limitations. Strippers are widely used in
industry to remove a variety of materials, including hydrogen
sulfide and volatile organics as well as ammonia, from aqueus
streams. The basic techniques have been applied both in process
and in wastewater treatment applications and are well understood.
The use of steam strippers with and without pH adjustment is
standard practice for the removal of hydrogen sulfide and ammonia
in the petroleum refining industry and has been studied
extensively in this context. Air stripping has treated municipal
and industrial wastewater and is recognized as an effective
technique of broad applicability. Both air and steam stripping
have successfully treated ammonia-laden wastewater, both within
the nonferrous metals manufacturing category or for similar
wastes in closely related industries.
The major drawback of air stripping is the low efficiency in cold
weather and the possibility of freezing within the tower.
Because lime may cause scaling problems and the types of towers
used in air stripping are not easily cleaned, caustic soda is
generally employed to raise the feed pH. Air stripping simply
transfer the ammonia from one water to air, whereas, steam
stripping allows for recovery and, if so desired, reuse of
289
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ammonia. Four primary tungsten plants use steam stripping to
recover ammonia from process wastewater and reuse the ammonia in
the manufacture of ammonium paratungstate. The two major
limitations of steam strippers are the critical column design
required for proper operation and the operational problems
associated with fouling of the packing material.
Operational Factors. Reliability and Maintainability: Strippers
are relatively easy to operate. The most complicated part of a
steam stripper is the boiler. Periodic maintenance will prevent
unexpected shutdowns of the boiler.
Packing fouling interferes with the intimate contacting of
liquid-gas, thus decreasing the column efficiency, and eventually
leads to flooding. The stripper column is periodically taken out
service and cleaned with acid and water with air sparging.
Column cutoff, is predicated on a maximum allowable pressure drop
across the packing of maximum "acceptable" ammonia content in the
stripper bottoms. Although packing fouling may not be completely
avoidable due to endothermic CaS04 precipitation, column runs
could be prolonged by a preliminary treatment step designed to
remove suspended solids originally present in the feed and those
precipitated after lime addition.
Demonstration Status. Steam stripping has proved to be an
efficient, reliable process for the removal of ammonia from many
types of industrial wastewaters that contain high concentrations
of ammonia. Industries using ammonia steam stripping technology
include the fertilizer industty, iron and steel manufacturing,
petroleum refining, organic chemicals manufacturing, and
nonferrous metals manufacturing. Eight plants in the nonferrous
metals manufacturing category currently practice steam stripping.
IN-PLANT TECHNOLOGY
The intent of in-plant technology for the nonferrous metals
manufacturing point source category is to reduce or eliminate the
waste load requiring end-of-pipe treatment and thereby improve
the efficiency of an existing wastewater treatment system or
reduce the requirements of a new treatment system. In-plant
technology involves water conservation, automatic controls, good
housekeeping practices, process . modifications, and waste
treatment.
Process Water Recycle
EPA is proposing BAT for most subcategories based on 90 percent
recycle of wet air pollution control and contact cooling
wastewater. The Agency has proposed a higher rate for certain
waste streams where reported rates of recycle are even higher.
Water is used in wet air pollution control systems to capture
particulate matter or fumes evolved during manufacturing.
290
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Cooling water is used to remove excess heat from cast metal
products.
Recycle is part of the technical basis for many of the
promulgated regulations in the nonferrous metals manufacturing
category. The Agency identified both demonstrated and feasible
recycle opportunities as early as 1973 in proposed effluent
limitations for secondary aluminum.
Recycling of process water is the practice of recirculating water
to be used again for the same purpose. An example of recycling
process water is the return of casting contact cooling water to
the casting process after the water passes through a cooling
tower. Two types of recycle are possible—recycle with a bleed
stream (blowdown) and total recycle. Total recycle may be
prohibited by the presence of dissolved solids. Dissolved solids
(e.g., sulfates and chlorides) entering a totally recycled waste
stream may precipitate, forming scale if the solubility limits of
the dissolved solids are exceeded. A bleed stream may be
necessary to prevent maintenance problems (pipe plugging or
scaling, etc.) that would be created by the precipitation of
dissolved solids. While the volume of bleed required is a
function of the amount of dissolved solids in the waste stream,
10 percent bleed is a common value for a variety of process waste
streams in the nonferrous metals manufacturing category. The
recycle of process water is currently practiced where it is cost
effective, where it is necessary due to water shortage, or where
the local permitting authority has required it. Recycle, as
compared to the once-through use of process water, is an
effective method of conserving water.
Application and Performance. Required hardware necessary for
recycle is highly site-specific. Basic items include pumps and
piping. Additional materials are necessary if water treatment
occurs before the water is recycled. These items will be
discussed separately with each unit process. Chemicals may be
necessary to control scale buildup, slime, and corrosion
problems, especially with recycled cooling water.
Recycling through cooling towers is the most common practice.
One type of application is shown in Figure VII-31. Casting
contact cooling water is recycled through a cooling tower with a
blowdown discharge.
A cooling tower is a device which cools water by bringing the
water into contact with air. The water and air flows are
directed in such a way as to provide maximum heat transfer. The
heat is transferred to air primarily by evaporation (about 75
percent), while the remainder is removed by sensible heat
transfer.
Factors influencing the rate of heat transfer and, ultimately,
the temperature range of the tower, include water surface area,
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tower packing and configuration, air flow, and packing height. A
large water surface area promotes evaporation, and sensible heat
transfer rates are lower in proportion to the water surface area
provided. Packing (an internal latticework contact area) is
often used to produce small droplets of water which evaporate
more easily, thus increasing the total surface area per unit of
throughput. For a given water flow, increasing the air flow
increases the amount of heat removed by maintaining higher
thermodynamic potentials. The packing height in the tower should
be high enough so that the air leaving the tower is close to
saturation.
A mechanical-draft cooling tower consists of the following major
components:
(1) Inlet-water distributor (2) Packing (3) Air fans (4)
Inlet-air louvers (5) Drift or carryover eliminators (6) Cooled
water storage basin.
Advantages and Limitations. Recycle offers economic as well as
environmental advantages. Water consumption is reduced and
wastewater handling facilities (pumps, pipes, clarifiers, etc.)
can thus be sized for smaller flows. By concentrating the
pollutants in a much smaller volume (the bleed stream), greater
removal efficiencies can be attained by any applied treatment
technologies. Recycle may require some treatment such as
sedimentation or cooling of water before it is reused.
The ultimate benefit of recycling process water is the reduction
in total wastewater discharge and .the associated advantages of
lower flow streams. A potential problem is the buildup of
dissolved solids which could result in scaling. Scaling can
usually be controlled by depressing the pH and increasing the
bleed flow.
Operational Factors. Reliability and Maintainability: Although
the principal construction material in mechanical-draft towers is
wood, other materials are used extensively. For long life and
minimum maintenance, wood is generally pressure-treated with a
preservative. Although the tower structure is usually made of
treated redwood, a reasonable amount of treated fir has been used
in recent years. Sheathing and louvers are generally made of
asbestos cement, and the fan stacks of fiberglass. There is a
trend to use fire-resistant extracted PVC as fill which, at
little or no increase in cost, offers the advantage of permanent
fire-resistant properties.
The major disadvantages of wccc! are its susceptibility to decay
and fire. Steel construction is occasionally used, but not to
any great extent. Concrete may be used but has relatively high
construction labor costs, although it does offer the advantage of
fire protection.
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Various chemical additives are used in cooling water systems to
control scale, slime, and corrosion. The chemical additives
needed depend on the character of the make-up water. All
additives have definite limitations and cannot eliminate the need
for blowdown. Care should be taken in selecting nontoxic or
readily degraded additives, if possible.
Solid Waste Aspects: The only solid waste associated with
cooling towers may be removed scale.
Demonstration Status. Predominantly two types of waste streams
in the nonferrous metals manufacturing category are currently
being recycled; casting contact cooling water and air pollution
control scrubber liquor. Two variations of recycle are used:
(1) a wastewater is recycled within a given process, and (2) a
wastewater is combined with others, treated, and the combined
wastewater is recycled to the processes from which it originated.
For example, scrubber liquor may be recycled within the scrubber,
or treated by sedimentation and recycled back to the scrubber.
Total recycle may become more wide-spread in the future if
methods for removal of dissolved solids, such as reverse osmosis
and ion exchange, become more common and less expensive.
The Agency observed extensive recycle of contact cooling water
and scrubber liquor throughout the category. Indeed, some plants
reported 100 percent recycle of process wastewater from these
operations. The Agency believes, however, that most plants may
have to discharge a portion of the recirculating flow to prevent
the excessive buildup of dissolved solids unless dragout of
solids in products or slags is sufficient to prevent this
buildup.
Process Water Reuse
Reuse of process water is the practice of recirculating water
used in one production process for subsequent use in a different
production process.
Application and Performance. Reuse of wastewater in a different
proces can include using a relatively clean wastewater for
another application, or using a relatively dirty water for an
application where water quality is of no concern.
Advantages and Limitations. Advantages of reuse are similar to
the advantages of recycle. Water consumption is reduced and
wastewater treatment facilities can be sized for smaller flows.
Also, in areas where water shortages occur, reuse i? an effective
means of conserving water.
Operational Factors. The hardware necessary for reuse of process
wastewaters varies, depending on the specific application. The
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basic elements include pumps and piping. Chemical addition is
not usually warranted, unless treatment is required prior to
reuse. Maintenance and energy use are limited to that required
by the pumps. Solid waste generated is dependent upon the type
of treatment used and will be discussed separately with each unit
process.
Demonstration Status. Reuse applications in the nonferrous
metals manfuacturing category are varied. For example, a
secondary uranium facility reuses wastewater from evaporation and
calcination wet air pollution control in raw material leaching
operations. Bauxite refineries commonly reuse water from red mud
inpoundments in digestion operations.
Process Water Use Reduction
Process water use reduction is the decrease in the amount of
process water used as an influent to a production process per
unit of production. Section V of each of the subcategory
supplements discusses water use in detail for each nonferrous
metals manufacturing operation. A range of water use values
taken from the data collection portfolios is presented for each
operation. The range of values indicates that some plants use
process water more efficiently than others for the same
operation.
Application and Performance. Noncontact cooling water can
replace contact cooling water in some applications. The use of
noncontact heat exchangers eliminates concentration of dissolved
solids by evaporation and minimizes scaling problems. A copper
refinery is currently using this method to achieve zero
discharge. However, industry-wide conversion to noncontact
cooling may not be possible because of a need for extensive
retrofitting. Certain molten metals require contact cooling to
produce desired surface characteristics. Some plants produce a
metal shot by allowing molten metal to flow through a screen into
a tank of water, immediately quenching the metal and producing a
spherical shot product. Shot, generally cannot be produced
without contact cooling water.
Air Cooling of_ Cast Metal Products
Application and Performance. Air cooling, for some operations,
is an alternative to contact cooling water but limited potential
except in low tonnage situations. For example, air cooling is
not generally used in the production of high tonnage casting for
several reasons. The casting line can be inordinately long (or
large), a result of an increased number of molds to compensate
for the slower cooling of the metal.
Operational Factors. Maintenance costs are generally higher
because of the longer conveyor, the added heat load on equipment
and lubricants, and the need for added air blowers. Air cooling
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without these process appurtenances might greatly reduce finished
metal production from rates now possible with water cooling.
Conversion to dry air pollution control equipment, discussed
further on in this section, is another way to eliminate water
use.
Processing and Granulation
Slag from pyrometallurgical processes is a solid waste that must
be disposed of or reprocessed. Slag can be prepared for disposal
by slag granulation or slag dumping.
Application and Performance. Slag granulation uses a high-
velocity water jet to produce a finely divided and evenly sized
rock, which can be used as concrete agglomerate or for road
surfacing. Slag dumping is the dumping and subsequent
solidification of slag, composed almost entirely of insolubles,
which can be crushed and sized for such applications as road
surfacing. Slag can be reprocessed if the metal content is high
enough to be economically recovered. Wet or dry milling, and
recovery of metal by melting can be used to process slag with
recoverable amounts of metal. Of course, in all slag reuse
processes, ultimate disposal of the reprocessed slag must be
considered.
Operational Factors. Although slag dumping eliminates the
wastewater associated with slag granulation, an additional factor
is that large volumes of dust are generated during subsequent
crushing operations and dust control systems may be necessary.
Demonstration Status. Four of the seven primary lead smelters
currently granulate slag prior to disposal. One of the four
plants granulates the slag, mixes the granulated slag in with ore
concentrate feed to sintering to control lead content of the
feed.
Dry Air Pollution Control Devices
Application and Performance. The use of dry air pollution
control devices would allow the elimination of waste streams with
high pollution potentials. The choice of air pollution control
equipment is complicated, and sometimes a wet system is the
necessary choice. The important difference between wet and dry
devices is that wet devices control gaseous pollutants as well as
particulates.
Wet devices may be chosen over dry devices when any of the
following factors are found: (1) the particle size is
predominantly under 20 microns, (2) flammable particles or gases
are to be treated at minimal combustion risk, (3) both vapors and
particles are to be removed from the carrier medium, (4) the
gases are corrosive and may damage dry air pollution control
295
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devices, and (5) the gases are hot and may damage dry air
pollution control devices.
Equipment for dry control of air emissions includes cyclones, dry
electrostatic precipitators, fabric filters, and afterburners.
These devices remove particulate matter, the first three by
entrapment and the afterburners by combustion.
Afterburner use is limited to air emissions consisting mostly of
combustible particles. Characteristics of the particulate-laden
gas which affect the design and use of a device are gas density,
temperature, viscosity, flammability, corrosiveness, toxicity,
humidity, and dew point. Particulate characteristics which
affect the design and use of a device are particle size, shape,
density, resistivity, concentration, and other physiochemical
properties.
To the extent that nonferrous metals manufacturing processes are
designed to limit the volume or severity of air emissions, the
volume of scrubber water used for air pollution control also can
be reduced. For example, new or replacement furnaces can be
designed to minimize emission volumes.
Advantages and Limitations. Proper application of a dry control
device can result in particulate removal efficiencies greater
than 99 percent by weight for fabric filters, elecrtrostatic
precipitators, and afterburners, and up to 95 percent for
cyclones.
Common wet air pollution control devices are wet electrostatic
precipitators, venturi scrubbers, and packed tower scrubbers.
Collection efficiency for gases will depend on the solubility of
the contaminant in the scrubbing liquid. Depending on the
contaminant removed, collection efficiencies ususally approach 99
percent for particles and gases.
Demonstration Status. Plants in the primary precious metals and
mercury, and secondary precious metals subcategories report the
use of dry air pollution control devices on furnaces and smelting
operations.
Good Housekeeping
Good housekeeping and proper equipment maintenance are necessary
factors in reducing wastewater loads to treatment systems.
Control of accidental spills of oils, process chemicals, and
wastewater from washdown and filter cleaning or removal can aid
in abating or maintaining the segregation of wastewater streams.
Curbed areas should be used to contain or control these wastes.
Leaks in pump casings, process piping, etc., should be minimized
to maintain efficient water use. One particular type of leakage
which may cause a water pollution problem is the contamination of
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noncontact cooling water by hydraulic oils, especially if this
type of water is discharged without treatment.
Good housekeeping is also important in chemical, solvent, and oil
storage areas to preclude a catastrophic failure situation.
Storage areas should be isolated from high fire-hazard areas and
arranged so that if a fire or explosion occurs, treatment
facilities will not be overwhelmed nor excessive groundwater
pollution caused by large quantities of chemical-laden fire-
protection water.
A conscientiously applied program of water use reduction can be a
very effective method of curtailing unnecessary wastewater flows.
Judicious use of washdown water and avoidance of unattended
running hoses can significantly reduce water use.
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pH Range
(mg/1)
TSS
Copper
Zinc
TABLE VI1-1
pH CONTROL EFFECT ON METALS REMOVAL
In
Day 1
Out
2.4-3.4 8.5-8.7
39
312
250
8
0.22
0.31
In
Day 2
16
120
32.5
Out
1.0-3.0 5.0-6.0
19
5. 12
25.0
In
Day 3
2.0-5.0
16
107
43.8
Out
6.5-8.1
7
0.66
0.66
TABLE VI1-2
EFFECTIVENESS OF SODIUM HYDROXIDE FOR METALS REMOVAL
In
Day 1
Out
In
Day 2
Out
In
Day 3
Out
pH Range
(mg/1)
Cr
Cu
Fe
Pb
Mn
Ni
Zn
TSS
2. 1-2.9
0.097
0.063
9.24
1 .0
0. 1 1
0.077
.054
9.0-9.3
0.0
0.018
0.76
0.11
0.06
0.011
0.0
13
2.0-2.4
0.057
0.078
15.5
1 .36
0.12
0.036
0. 12
8.7-9. 1
0.005
0 . 0.1 4
0.92
0.13
0.044
0.009
0.0
1 1
2.0-2.4
0.068
0.053
9.41
1 .45
0.11
0.069
0. 19
8.6-9. 1
0.005
0.019
0.95
0. 1 1
0.044
0.01 1
0.037
1 1
298
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TABLE VI1-3
EFFECTIVENESS OF LIME AND SODIUM HYDROXIDE FOR METALS REMOVAL
Day 1
Day 2
Day 3
(mg/1)
Al
Co
Cu
Fe
Mn
Ni
Se
Ti
Zn
TSS
Metal
Cadmium (Cd*-1-)
Chromium (Cr+++ )
Cobalt (Co++)
In
9.2-9.6
37.3
3.92
0.65
137
175
6.86
28.6
143
18.5
4390
IORETICAL
OF
Out In
8.3-9.8 9.2
0.35 38.1
0.0 4.65
0.003 0.63
0.49 110
0.12 205
0.0 5.84
0.0 30.2
0.0 125
0.027 16.2
9 3595
TABLE VI
SOLUBILITIES OF
SELECTED METALS
As Hydroxide
Out
7.6-8.1
0.35
0.0
0.003
0.57
0.012
0.0
0.0
0.0
0.044
13
1-4
HYDROXIDES AND
IN PURE WATER
Solubility of
In
9.6
29.9
4.37
0.72
208
245
5.63
27.4
115
17.0
2805
SULFIDES
metal ion,
As Carbonate
Out
7.8-8.2
0.35
0.0
0.003
0.58
0. 12
0.0
0.0
0.0
0.01
13
mg/1
As Sulfide
Copper
Iron (Fe++)
Lead (Pb++)
Manganese
Mercury
Nickel (Ni++)
Silver (Ag+)
Tin (Sn*-1-)
Zinc (Zn++)
2.3 x 10-s
8.4 x 10-*
2.2 x 10-1
2.2 x 10-2
8.9 x 10-i
2.1
1 .2
3.9 x 10-*
6.9 x 10-3
13.3
1.1 x 10-*
1 .1
1.0 x 10-'
7.0 x 10~3
3.9 x 10-2
1.9 x 10-1
2.1 x 10-1
7.0 x 10-*
6.7 x 10-10
No precipitate
1 .0 x 10-8
5.8 x 10-18
3.4 x 10-5
3.8 x 10-»
2.1 x 10-3
9.0 x 10-20
6.9 x lO-8
7.4 x 10~12
3.8 x lO-8
2.3 x 10-7
299
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TABLE VI1-5
SAMPLING DATA FROM SULFIDE
PRECIPITATION-SEDIMENTATION SYSTEMS
Lime, FeS, Poly- Lime, FeS, Poly- NaOH, Ferric
electrolyte, electrolyte, Chloride, Na2S
Treatment Settle, Filter Settle, Filter Clarify (1 stage)
PH
(mg/1
Cr+6
Cr
Cu
Fe
Ni
Zn
These
In
5.0-6.
25.6
32.3
0.52
39.5
Out
8 8-9
<0.014
<0. 04
0.10
<0.07
data were obtained from
Summary Report,
Metal Finishing
Control
Industry
In
7.7
0.022 <0
2.4 <0
. 108 0
0.68 <0
33.9 0
three sources:
and Treatment
Out
7.38
.020
. 1
.6
. 1
.01
Technology
: Sulfide Precipitation,
In Out
11 .45
18.35
0.029
0.060
for
USEPA,
<.005
<.005
0.003
0.009
the
EPA
No. 625/8/80-003, 1979.
Industrial Finishing, Vol. 35, No. 11, November, 1979.
Electroplating sampling data from plant 27045.
300
-------
TABLE VII-6
SULFIDE PRECIPITATION-SEDIMENTATION PERFORMANCE
Parameter Treated Effluent
(mg/1)
Cd 0.01
Cr (T) 0.05
Cu 0.05
Pb 0.01
Hg 0.03
Ni 0.05
Ag 0.05
Zn 0.01
Table VI1-6 is based on two reports:
Summary Report, Control and Treatment Technology for the
Metal Finishing Industry; Sulfide Precipitation, USEPA, EPA
No. 625/8/80-003, 1979.
Addendum to Development Document for Effluent Limitations
Guidelines and New Source Performance Standards, Major
Inorganic Products Segment of Inorganics Point Source
Category, USEPA., EPA Contract No. EPA-68-01-3281 (Task 7),
June, 1978.
301
-------
Table VII-7
FERRITE CO-PRECIPITATION PERFORMANCE
Metal Influent(mg/1) Effluent(mg/1)
Mercury 7.4 0.001
Cadmium 240 0.008
Copper 10 0.010
Zinc 18 0.016
Chromium 10 <0.010
Manganese 12 0.007
Nickel 1,000 0.200
Iron 600 0.06
Bismuth 240 0.100
Lead 475 0.010
NOTE: These data are from:
Sources and Treatment of Wastewater in the Nonferrous
Metals Industry, USEPA, EPA No. 600/2-80-074, 1980.
. TABLE .VI1-8
CONCENTRATION OF TOTAL CYANIDE
(mg/1)
Plant Method In Out
1057 ' FeSO4 2.57 0.024
2.42 0.015
3.28 0.032
33056 FeSO4 - 0.14 0.09
0.16 0.09
12052 2nS04 0.46
0.12
Mean 0.07
302
-------
Plant ID I
06097
13924
18538
30172
36048
mean
Table VII-9
MULTIMEDIA FILTER PERFORMANCE
TSS Effluent Concentration, mq/1
0
1
3
1
1
2
2
.0,
.8,
.0,
.0
.4,
• 1 /
.61
0.
2.
2.
7.
2.
0,
2,
0,
0,
6,
0.
5.
5.
1 .
1 .
5
6, 4.0, 4.0, 3.0, 2.
6, 3.6, 2.4, 3.4
0
5
2, 2.8
TABLE VII-10
PERFORMANCE OF SELECTED SETTLING SYSTEMS
PLANT ID
i
01057
09025
11058
12075
19019
33617
40063
44062
46050
SETTLING
DEVICE
Lagoon
Clarifier &
Settling
Ponds
Clarifier
Settling
Pond
Settling
Tank
Clarifier &
Lagoon
Clarifier
Clarifier
Settling
Tank
SUSPENDED SOLIDS CONCENTRATION (mg/1)
Day 1
In
54
1100
451
284
170
-
4390
182
295
Out
6
9
17
6
1
—
9
13
10
Day
In
56
1900
-
242
50
1662
3595
118
42
2
Out
6
12
-
10
1
16
12
14
10
Day 3
In
50
1620
-
502 14
- -
1298
2805 13
174 23
153 8
Out
5
5
-
4
303
-------
Table VII-11
SKIMMING PERFORMANCE
Oil & Grease
mg/1
Plant Skimmer Type Ln Out
06058 API 224,669 " 17.9
06058 Belt 19.4 8.3
TABLE VI1-12
SELECTED PARITION COEFFICIENTS
Log Octanol/Water
Priority Pollutant Partition Coefficient
1 Acenaphthene 4.33
11 1,1,1-Trichloroethane 2.17
13 1,1-Dichloroethane 1.79
15 1,1,2,2-Tetrachloroethane 2.56
18 Bis(2-chloroethyl)ether 1.58
23 Chloroform 1.97
29 1,1-Dichloroethylene 1.48
39 Fluoranthene 5.33 .
44 Methylene chloride 1.25
64 Pentachlorophenol 5.01
66 Bis(2-ethylhexyl)
phthalate 8.73
67 Butyl benzyl phthalate 5.80
68 Di-n-butyl phthalate 5.20
72 Benzo(a)anthracene 5.61
73 Benzo(a)pyrene 6.04
74 3,4-benzofluoranthene 6.57
75 Benzo(k)fluoranthene 6.84
76 Chrysene 5.61
77 Acenaphthylene 4.07
78 Anthracene 4.45
79 Benzo(ghi)perylene 7.23
80 Fluorene 4.18
81 Phenanthrene 4.46
82 Dibenzo(a,h)anthracene 5.97
83 Indeno(1,2,3,cd)pyrene 7.66
84 Pyrene 5.32
85 Tetrachloroethylene 2.88
86 Toluene 2.69
304
-------
TABLE VII-13
TRACE ORGANIC REMOVAL BY SKIMMING
API PLUS BELT SKIMMERS
(From Plant 06058)
Oil & Grease 225,000 14.6
Chloroform 0.023 0.007
Methylene Chloride 0.013 0.012
Naphthalene 2.31 0.004
N-nitrosodiphenylamine 59.0 0.182
Bis-2-ethylhexyl phthalate 11.0 0.027
Diethyl phthalate
Butylbenzyl phthalate 0.005 0.002
Di-n-octyl phthalate 0.019 0.002
Anthracene - phenanthrene 16.4 0.014
Toluene 0.02 0.012
Table VII-14
COMBINED METALS DATA EFFLUENT VALUES (mg/1)
One Day 10 Day Avg. 30 Day Avg
Mean Max. Max. Max.
Cd 0.079 0.34 0.15 0.13
Cr 0.084 0.44 0.18 0.12
Cu 0.58 1.90 1.00 • 0.73
Pb 0.12 0.42 0.20 0.16
Ni 0.74 1.92 1.27 1.00
Zn 0.33 1.46 0.61 0.45
Fe 0.41 1.20 0.61 0.50
Mn 0.16 0.68 0.29 - 0.21
TSS 12.0 41.0 19.5 15.5
305
-------
TABLE VII-15
L&S PERFORMANCE
ADDITIONAL POLLUTANTS
Pollutant
Sb
As
Be
Hg
Se
Ag
Tl
Al
Co
F
B
Mo
Sm
U
Ra 226
Ti
In
Ge
*Value in picocuries per liter,
Average Performance (mg/1)
0.7
0.51
0.30
0.06
0.30
0.10
0.50
2.24
0.05
14.5
0.27
1.41
1.07
1.23
6.17*
0.084
0.084
0.084
TABLE VII-16
COMBINED METALS DATA SET - UNTREATED WASTEWATER
Pollutant
Cd
Cr
Cu
Pb
Ni
Zn
Fe
Mn
TSS
Min. Cone, (mg/1)
<0. 1
<0. 1
<0. 1
<0. 1
<0. 1
<0. 1
<0. 1
4.6
Max. Cone, (mg/1)
3.83
116
108
29.2
27.5
337.
263
5.98
4390
306
/
-------
TABLE VII-17
MAXIMUM POLLUTANT LEVEL IN UNTREATED WASTEWATER
ADDITIONAL POLLUTANTS
(mg/D
Pollutant
As
Be
Cd
Cr
Cu
Pb
Ni
Ag
Zn
F
Fe
O&G
TSS
As
Be
Cd
Cr
Cu
Pb
Ni
Ag
Zn
F
Fe
O&G
TSS
As & Se
4.2
<0. 1
0.18
33.2
6.5
3.62
-
16.9
352
TABLE
Mo & B
12.4
0.01
0.05
13.0
2.92
2.70
4.60
0.002
2.35
4.80
98.2
7.7
87
Be Ag
10.24
<0.1
8.60 0.23
1.24 110.5
0.35 11.4
100
4.7
0.12 1512
646
16
796 587.8
VI I- 17 Continued
Sn
6.6
0.20
0.42
0.94
0.50
9.0
4.1
0.40
29
0.5
-
F
<0. 1
22.8
2.2
5.35
0.69
<0.1
760
2.8
5.6
U & Ra 226
0.008
.035
.020
.065
.060
0.170
_
-
Sb
0.024
0.83
0.41
76.0
0.53
-
134
307
-------
TABLE VII-18
PRECIPITATION-SETTLING-FILTRATION (LS&F) PERFORMANCE
Plant A
Parameters
No Pts.
Range mq/1
For 1979-Treated Wastewater
Cr
Cu
Ni
Zn
Fe
47
12
47
47
0.015
0.01
0.08
0.08
0.13
0.03
0.64
0.53
47
28
47
47
21
0.01
0.005
0.10
0.08
0.26
- 0.07
- 0.055
- 0.92
- 2.35
-1.1
For 1978-Treated Wastewater
Cr
Cu
Ni
Zn
Fe
Raw Waste
Cr
Gu
Ni
Zn
Fe
5
5
5
5
5
32.0
0.08
1 .65
33.2
10.0
72.0
0.45
20.0
32.0
95.0
Mean +_
std. dev.
0.045 +0.029
0.019 +0.006
0.22 +0.13
0.17 To.09
Mean + 2
std. dev,
0.10
0.03
0.48
0.35
0.06 +0.10 0.26
0.016 To.010 0.04
0.20 To.14. 0.48
0.23 +0.34 0.91
0.49 +0.18 0.85
308
-------
TABLE VII-19
PRECIPITATION-SETTLING-FILTRATION (LS&F) PERFORMANCE
Plant B
Parameters
No Pts.
Range mq/1
For 1
For 1
Total
979-Treated Wastewater
Cr
Cu
Ni
Zn
Fe
TSS
175
176
175
175
174
2
0.0
0.0
0.01
0.01
0.01
1 .00
- 0.40
- 0.22
- 1 .49
- 0.66
- 2.40
- 1 .00
978-Treated Wastewater
Cr
Cu
Ni
In
Fe
1974-1
Cr
Cu
Ni
Zn
Fe
144
143
143
131
144
979-Treated
1288
1290
1287
1273
1287
0.0
0.0
0.0
0.0
0.0
- 0.70
- 0.23
- 1 .03
- 0.24
- 1 .76
Wastewater
0.0
0.0
0.0
0.0
0.0
- 0.56
- 0.23
- 1 .88
- 0.66
-3.15
Raw Waste
Cr
Cu
Ni
Zn
Fe
TSS
3
3
3
2
3
2 1
2.80
0.09
1 .61
2.35
3.13
77
- 9.15
- 0.27
- 4.89
- 3.39
-35.9
-466.
Mean +_
std. dev.
0.068 +0.075
0.024 +.0.021
0.219 +0.234
0.054 +0.064
0.303 +0.398
0.059 +0.088
0.017 +0.020
0.147 +0.142
0.037 +0.034
0.200 +0.223
0.038 +0.055
0.011 +0.016
0.184 +"0.211
0.035 +0.045
0.402 +"0.509
5.90
0.17
3.33
22.4
Mean + 2
std. dev,
0.22
0.07
0.69
0.18
1.10
0.24
0.06
0.43
0. 1 1
0.47
0.15
0.04
0.60
0.13
1 .42
309
-------
TABLE VI1-20
PRECIPITATION-SETTLING-FILTRATION (LS&F) PERFORMANCE
Plant C
For Treated Wastewater
Parameters No Pts.
For Treated Wastewater
Range mq/1
Mean +_
std. dev.
Mean + 2
std. dev,
Cd
Zn
TSS
pH
103
103
103
103
For Untreated Wastewater
Cd
Zn
Fe
TSS
pH
103
103
3
103
103
0.010 - 0.500 0.049 ±0.049 0.147
0.039 - 0.899 0.290 ±0.131 0.552
0.100 - 5.00 1.244 ±1.043 3.33
7.1 - 7.9 9.2*
0.039 - 2.319 0.542 +0.381 1.304
0.949 -29.8
0.107 - 0.46
0.80 -19.6
6.8
- 8.2
11.009
0.255
5.616
7.6*
:6.933 24.956
•2.896 11.408
* pH value is median of 103 values.
310
-------
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in
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CO
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^_
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T— OO OO
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odd
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odd
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t— oo m
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odd
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vt
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m
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COO
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CM O
CM O
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in
vo o
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CM O
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ON
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m
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t~
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m
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m t- -
O O CM
m CM vo
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vO CM 00
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CM *— T- m
v£> o >
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co es
r*. T— o
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312
-------
Table VII-22
TREATABILITY RATING OF PRIORITY POLLUTANTS UTILIZING
CARBON ADSORPTION
"rioritv ftsllutant
'Removal Rating
1. acenapnthene R
2. acrolein L
3. acrylonitrile L
4. benzene "
5. benzidine R
6. carbon tetrachloride M
(tetrachloronethane)
7. chlorobenzene R
8. 1,2,4-trichlorobenzene H
9. hexachlorobenzene H
10. 1,2-dichioroethane M
li. 1,1.1-tnchloroethane H
12. hexachiorcethane H
13. 1,1-dichlorcethane H
14. 1,1,2-trichloroethane H
15. 1,1,2,2-tetrachloroethane H
16. chloroethane L
17. bis(chloromethyl)ether
18. bis(2-chloroethyl)ether M
19. 2-chloroethyl vinyl ether L
(mixed)
20. 2-chloronaphthalene H
21. 2,4,6-trichlorophenol H
22. parachloroneta cresol H
23. chloroform (trichloromethane) L
24. 2-chloropherol R
25. 1,2-dichlorobenzene H
26. 1,3-dichlorobenzene H
27. 1,4-dichlorcbenzene B
28. 3,3'-dichlorobenzidine R
29. 1,1-dichloroethylene L
30. 1,2-trans-dichlorcethylene L
31. 2,4-dicnlorophenol R
32. 1,2-dichloroprepane H
33. 1,2-dichloropropylene H
(1,3,-dichloropropenfcj
34. 2,4-duwthylphenol H
35. 2,4-dinitrotoluene R
36. 2,6-dinitrotoluene H
37. 1,2-dipnenylhydrazine H
38. ethylbenzene . H
39. fluoranthene R
40. 4-chlorophenyl phenyl ether H
41. 4-brcnophenyl phenyl ether H
42. bis(2-chloroisopropyl)ether M
43. bis(2-chloroethoxy(methane H
44. methylene chloride L
(dichl oromethane)
45. methyl chloride (chloronethane) L
46. methyl bromide (bromonethane) L
47. bramoform (tribiuimethane) H
46. dichlorobn-iimethanc H
Priority ttollutant
Ratino
49.
50.
51.
52.
53.
54.
55.
56.
57.
58.
59.
•
61.
62.
63.
64.
65.
66.
67.
68.
69.
70.
71.
72.
73.
74.
75.
76.
77.
78.
79.
80.
81.
82.
83.
84.
85.
86.
87.
88.
106.
107.
108.
109.
110.
111.
112.
tr i chlorof 1 uorcre thane
dichlorodif lucre-ore thane
ehlorodibronoie thane
hexachlorobutadiene
hexachlorocyclopentadiene
iautjiLiiuie
naphthalene
nitrobenzene
2-nitrophenol
4-fiitrophenol
2 , 4-d in i trophenol
4 , 6-^initrO"<^-'iesol
N-n 1 1 roaod imethy 1 atune
N-n 1 1 roaod i pheny 1 amine
N-n i trosod i -^-propy l«iune
pentachlorophenol
phenol
bis( 2-ethylhexyl)phthalate
butyl benzyl phthalate
di-n-butyl phthalate
di-n-octyl phthalate
diethyl phthalate
dunethyl phthalate
1,2-benzanthraoene (benzo
(a) anthracene)
benzo(a)pyrene (3,4-benzo-
pyrene)
3 , 4-benaof luoranthene
( benzo ( b ) fl uoranthene )
11 , 12-benzof 1'jaranthene
(benzo(k) fluoranthene)
chryaene
acenaphthylene
anthracene
1,12-benzoperylene (benzo
(ghi)-perylene)
fluorene
phenanthrene
1 , 2 , 5 , 6-d ibenza thracene
(dibenao (a,h) anthracene)
indeno (1,2,3-od) pyrenc
(2,3-o-phenylene pyrene)
pyrene
tetrachloroethylene
toluene
trichloroethylene
vinyl chloride
(chloroethylene)
PCT-1242 (Arochlor 1242)
PCB-1254 (Arcchlor 1254)
PCB-1221 (Arochlor 1221)
PCB-1332 (Arochaor 1232)
PCB-1248 (Arochlor 1248)
PCB-1260 (Arochlor 1260)
FCB-1016 (Arochlor 1016)
M
L
H
H
R
H
B
H
H
H
H
«
H
H
R
H
H
H
H
H
H
R
R
R
H
H
H
H
H
H
H
H
R
H
-
M
H
L
L
R
H
R
H
H
H
H
: Explanation of ftsncval RAting*
Category H (high removal)
adsorbs at levels £ 100 mg/g carbon at C, - 10 mg/1
adsorbs at levels T 100 nq/g carbon at Ct < 1.0 nq/1
Category H (moderate
adsorbs at levels > 100 mg/g carbon at C, • 10 ag/1
adsorb* at levels 7 100 mg/g carbon at CJ < 1.0 mg/1
Category L (low renoval)
adsorbs at levels < 100 nq/g carbon at C, • 10 «j/l
adsorb* at levels < 10 nq/g carbon at Cf < 1.0 nq/1
Cj • final concentrations of priority pollutant at equilibrium
31 3
-------
Table VII-23
CLASSES OF ORGANIC COMPOUNDS ADSORBED ON CARBON
Organic Chemical Class
Aromatic Hydrocarbons
Polynuclear Aromatics
Chlorinated Aromatics
Phenolics
Chlorinated Phenolics
High Molecular Weight Aliphatic and
Branch Chain Hydrocarbons
Chlorinated Aliphatic Hydrocarbons
High Molecular Weight Aliphatic Acids
and Aromatic Acids
High Molecular Weight Aliphatic Amines
and Aromatic Amines
High Molecular Weight Ketones, Esters,
Ethers and Alcohols
Surfactants
Soluble Organic Dyes
Examples of Chemical Class
benzene, toluene, xylene
naphthalene, anthracene
bephenyls
chlorobenzene, polychlorinated
biphenyls, aldrin, endrin,
toxaphene, DDT
phenol, cresol, resorcenol
and polyphenyls
trichlorophenol, pentachloro-
phenol
gasoline, kerosine
carbon tetrachloride,
perchloroethylene
tar acids, benzole acid
aniline, toluene diamine
hydroquinone, polyethylene
glycol
alkyl benzene sulfonates
melkylene blue, Indigo carmine
High Molecular Weight includes compounds in the broad range of from 4 to 20
carbon atoms.
314
-------
Table VII-24
ACTIVATED CARBON PERFORMANCE (MERCURY)
Plant
A
B
C
Mercury levels - mg/1
In
28.0
0.36
0.008
Out
0.9
0.015
0.0005
Table VII-25
ION EXCHANGE PERFORMANCE
Parameter
All Values mg/1
Al
Cd
Cr+3
Cr+6
Cu
CN
Au
Fe
Pb
Mn
Ni
Ag
SO4
Sn
Zn
Plant
Prior To
Purifi-
cation
5.6
5.7
3.1
7.1
4.5
9.8
_
7.4
-
4.4
6.2
1.5
_
1.7
14.8
A
After
Purifi-
cation
0.20
0.00
0.01
0.01
0.09
0.04
_
0.01
-
0.00
0.00
0.00
_
0.00
0.40
Plant
Prior To
Purifi-
cation
_
-
-
—
43.0
3.40
2.30
-
1.70
w
1.60
9.10
210.00
1.10
-
B
After
Purifi-
cation
_
-
-
_
0.10
0.09
0.10
-
0.01
_
0.01
0.01
2.00
0.10
-
315
-------
Table VII-26
MEMBRANE FILTRATION SYSTEM EFFLUENT
Specific
Metal
Al
Cr, (+6)
Cr (T)
Cu
Fe
Pb
CN
Ni
Zn
TSS
facturers
antee
0.5
0.02
0.03
0.1
0.1
0.05
0.02
0.1
0.1
Plant
In
0.46
4.13
18.8
288
0.652
<0.005 <
9.56
2.09
632
19066
Out
0.01
0.018
0.043
0.3
0.01
:o.oos
0.017
0.046
0.1
Plant
In
5.25
98.4
8.00
21.1
0.288
<:0.005
194
5.00
13.0
31022
Out
<0.005
0.057
0.222
0.263
0.01
30.005
0.352
0.051
8.0
Predicted
Performan
0.05
0.20
0.30
0.05
0.02
0.40
0. 10
1.0
Pollutant
(mg/1)
Cr+6
Cu
CN
Pb
Hg
Ni
Ag
Sb
Zn
Table VII-27
PEAT ADSORPTION PERFORMANCE
In
35,000
250
36.0
20.0
1.0
2.5
1.0
2.5
1.5
Out
0.04
0.24
0.7
0.025
0.02
0.07
0.05
0.9
0.25
316
-------
Table VII-28
ULTRAFILTRATION PERFORMANCE
Parameter Feed (mg/1) Permeate (mg/1)
Oil (freon extractable) 1230 4
COD 8920 148
TSS 1380 13
Total Solids 2900 296
317
-------
19'
IB'1
to-'
u
a
u
to-»
a
0 10"*
0
p
< .7
c '*
K
u
u
1.."
u
10"
,,-u
A,(OM|
a >
> * » \« ii it
Figure VII-1
CO?IPARATIVE SOLUBILITIES OF 1-ffiTAL HYDROXIDES
AND SULFIDE AS A FUNCTION OF pH
Source: DeveLopment Document for the Proposed Effluent Limita-
tions Guidelines and New Source Performance Standards
for the Zinc Segment of the Nonferrous Metals Manufac-
turing Point Source Category.EPA 440/1-74-033,
November,1974.
318
-------
.
o
o
o
:>
o
0 C
o
<
0
o c
coo
w
C
-------
0.40
SODA ASH AND
CAUSTIC SODA
Figure VII-3
LEAD SOLUBILITY IN THREE ALKALIES
Source: Lanovette, Kenneth, "Heavy Metals Removal," Chemical
Sngineering/Deskbook Issue, October 17, 1977.
320
-------
t • i i , i , i i i i i ' , , i > , i
i . t : • 1 i i 1 . '.;.;,! i
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<•
y
(l/6iu) uottsauaauoQ wsny^g pawajj, tiinttupe^
i
001 0.1 1.0 10 11
Cailniiiini Raw Waste Continuation (iny/l)
points with • taw waste concenlialioii (Nunilier ol nliseivatiniis = 2)
||MII 0. 1 nig/1 wei ft not incluilcil in
muni effectiveness calculations. FIGURE VII -4
IIYDROXIRE PRECIPITATION SEDIMENTATION EFFECTIVENESS
CADMIUM
321
-------
I 1 II
Tl
I I
III I
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©
I I
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vs
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•to 5
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= s
> =
UJ LU
B «
a c
u
uu
0
(l/fitu) uoaEJausauoQ
pamij.
322
-------
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I I
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TT I i I I
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i I i I
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i i
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i i
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z
UJ
a
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<
c
c
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a
x
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a
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(1/fiui)
323
-------
Ml i I I I
I I I I I
I I
I I
I I I I I
I I
I i
I I I I I I I
I i I I I I
I I I
I I ' I I I I
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5
s
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u
V!
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U.
U.
kU
U
U
bU W
5 2
£ £
uZ P
H
U
(|/6ui) uoauzussuoQ
a Uiauufajj.
324
-------
; i i i i i ' i t i : > i : • i i i i p ,
> i • i i 1 ; 1 i I : i i i i i . i
. ; i 1 ' x X | i | i | •; • r i '
i :
1
i
i
1
1
^ . i ' » - : I ' .
" i , i ; i
i ! ' i I i t ' t
It II
'ill i
1
i
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1 ' 1 f 1 M* \*j '.
I 1
t » i i
| i
t
i i i i -^ i
i 1 - .
i
i 1
i
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1 i
i
t
i
i
I
1
i
• <{*j
' f 1
1 f
1
I
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1 ! • 11
, i
1 i
1
i s * i ! i
; (
1 !__
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t
i
I J
)
€
:s
i
i
i 1
1
i i
;
i
i
I *>!
1 1
,
t
— 5 =
(l/fiui) uoaemiaauoQ man^g paarajj, ja^ajjv 0
325
0.1 10 10 tOO 10
0 Nickel Row Waste Concentration (nig/1) (Number of nlismafions = 13)
x Aliiiniiiuiii Raw Waste Conccnlialion (my/1) (Ninnlier ol uliscivalioiis - S)
FIGURE VII -8
HYDROXIDE PRECIPITATION SEDIMENTATION EFFECTIVENESS
-------
en
ex
I I
I I I I
I I I I
I I I I I
I i
'Mil I
0
i i ' i i i I
ill I
I I I I I I
I I I
0
i i
©
-------
I I I
II I -
•(III I
0
I I
I I I I
II I.
| I
I I I I I I
9
I I I I I I I I
©
Mill I
t I
Vj VtV ! j
! ' I I
0
0
j .
0
I I I l | | i
0
0
vs
UJ
a
uu
u>
u.
U
tt
5lg
UJ UJ —
e "* s
UJ
zi
UJ
a
a
a
(j/fiui) uoaeuussuoQ
pazeajj,
327
-------
I !
I I
I !
I I
I I t I
I I
Mil! I
s.
I I i i t I I I
I I 1 I I
i I
I t I I
I I I
I I
S
5
I
to
I
I
i,
(1/fiui) uoiauuiaauoQ
paaaajj. assueoue^
328
-------
' I I I
I I
Mill l
I !
i ! f i
r r
0
©j
©
0
i t
111 i i ' i
-
0
©
I I ! I i
0
<3
0
i i
0
9
ill \ j
I I I
I i I I I
Ml!
•£•
i r j
§
s
|
s
2
«
u
2
UJ
>
a
= Z
8
&.
UJ
C
X
o
(l/6ui)
paisatj.
329
-------
EFFLUENT!
INFLUENT
ALUM
WATER
LEVEL
STORED
BACKWASH
WATER
ti
u
FILTER
COMPARTMENT
SAND
FILTER
MEDIA
f u u u u u
COLLECTION CHAMBER
THREE WAY VALVE
• •-•—FILTER
•—BACKWASH-*-
DRAIN
Figure VII-U
GRANULAR BED FILTRATION
330
-------
PERFORATED
BACKING PLATE
FABRIC
FILTER MEDIUM
SOLID
RECTANGULAR
END PLATE
INLET
SLUDGE
FABRIC
FILTER MEDIUM
ENTRAPPED SOLIDS
FILTERED LIOUJO OUTLET
PLATES AND FRAMES AR£
PRESSED TOGETHER DURING
FILTRATION CYCLE
RECTANGULAR
METAL PLATE
RECTANGULAR FRAME
Figure VII-15
PRESSURE FILTRATION
331
-------
SEDIMENTATION BASIN
INLET ZONE
BAFFLES TO MAINTAIN
QUIESCENT CONDITIONS
OUTLET ZONE
INLET LIQUID
\.
l^, * SETTLING PARTICLE
• "**-**.* • TRAJECTORY . '«
"
OUTLET LIQUID
BELT-TYPE SOLIDS COLLECTION
MECHANISM
t
SETTLED PARTICLES COLLECTED
AND PERIODICALLY REMOVED
CIRCULAR CLARITIES
SETTLING ZONE.
INLET LIQUID
CIRCULAR BAFFLE
I
—I - • • .
INLET ZONE -^
-7—.« .V. •." • T.' . •v• .FL0.W.'.
^^
-------
FLANGE
WASTE WATER
INFLUENT
DISTRIBUTOR
WASH WATER
SURFACE WASH
MANIFOLD
BACKWASH
BACKWASH
REPLACEMENT CARBON
CARBON REMOVAL PORT
TREATED WATER
SUPPORT PLATE
Figure VII-1 7
ACTIVATED CARBON ADSORPTION COLUMN
333
-------
CONVEYOR DRIVE
r— BOWL DRIVE
LIQUID
OUTLET
I i !
CYCLOCEAR
SLUDGE
DISCHARGE
BOWL
REGULATING
RING
IMPELLER
Figure VII-18
CENTRIFUGATION
334
-------
a)
335
-------
CONTROLS
OZONE
GENERATOR
DRY AIR
OZONE
REACTION
TANK
HXh
TREATED
WASTE
RAW WASTE-
Figure VII-20
TYPICAL OZONE PLANT FOR WASTE TREATMENT
336
-------
MIXER
P1F
ST
se
ST
T)
WASTEWATER g1
FEED TANK '
I
•j"- J
'
h
'ST 5
AGE 3
3
v_
!
(ft
:ONO J
AGE 3
3
to
4IRD §
•AGE 3
'
I PUMP
TREATED WATER
c
1 1
c
c=
UJ
' _ EXHAUST
=3
i
c
t
=3
=3
J_L
C
i
L
i
GAS
— — TEMPERATURE
CONTROL
•— PH MONITORING
TEMPERATURE
CONTROL
PM MONITORING
— . TEMPERATURE
— — CONTROL
— — PH MONITORING
OZONE
OZONE
GENERATOR
Figure VII-2.1
UV/OZONATION
337
-------
ta
3
X
y
e
o
E
0
<
0
0.
<
•>
y
2
j
(2
^
I
|
X
a
<
>
COOLING
MATER
1 -
r~ ^
IOT VAPOn
~
I
t
(
•4 •
m*^^
* 3 J
J £ 31
« »r*n 1
« iHi 8
a u u
f < *
0 >
u
1
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y
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U in
1
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S
1
y
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n
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5§
in u 1
1
<
*1
CONDCNS/
y
>-
CONCENTBA
3S03M MO
crllM Hn-l
Ik
y
H
<
X
H
Z
y
Z
0
CM
CM
I
(U
H
2:
p*
M
P
C/
w
s
o
M
H
<5 i
S3 3 i|
2 2|
S »y
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K
y f
5 o
0 H
I- <
0 5
y 0
fc W
c
o
<
X
o
<
>
u
u
E
U
Z
-------
OILY WATER
INFLUENT
WATER
DISCHARGE
MOTOR
DRIVEN
RAKE
\ I ii i i
OVERFLOW
SHUTOFF
VALVE
EXCESS
AIR OUT
LEVEL
CONTROLLER
TO SLUDGE
TANK •"*
Figure VII-23
DISSOLVED AIR FLOTATION
339
-------
CONDUIT
TO MOTOR
INFLUENT
CONDUIT TO
OVERLOAD
At. ARM
COUNTERFLOW
INFLUENT WELL
DRIVE UNIT
OVERLOAD ALARM
EFFLUENT WEIR
DIRECTION OF ROTATION
EFFLUENT PIPE
EFFLUENT CHANNEL
PLAN
TURNTABLE
BASE
HANDRAIL
WEIR
INFLUENT
CENTER COLUMN
CENTER CAGE
STILTS
CENTER SCRAPER
Figure VII-24
GRAVITY THICKENING
340
-------
WASTE WATCH CONTAINING
DISSOLVED METALS OR
OTHER IONS
OIVERTER VALVE
RECENERANT
SOLUTION
DISTRIBUTOR
SUPPORT
REGENERANT TO REUSE,
TREATMENT. OR DISPOSAL
•DIVEHTER VALVE
METAL-FREE WATER
FOR REUSE OR DISCHARGE
Figure VII-25
ION EXCHANGE WITH REGENERATION
341
-------
MACRO MOLECULES
ANO SOLIDS
MOST
MEMBRANE
450 ?S1
FEED-
WATER
PERMEATE (WATER)
MEMBRANE CROSS SECTION,
IN TUBULAR, HOLLOW FIBER.
OR SPIRAL-WOUND CONFIGURATION
. o
•o'. o'/° •» i.*0
o . • • / o •
* • ° • °.o*o7° • o •
o 0*0 ° ° /. o o .
• , • ^ ! f * I
^CONCENTRATE
(SALTS)
o o
>
O SALTS OR SOLIOS
• WATER MOLECULES
Figure VII-28
SIMPLIFIED REVERSE OSMOSIS SCHEMATIC
342
-------
PERMEATE
TUBE
ADHESIVE BOUND
SPIRAL. MODULE
BACKING MATERIAL
MESH SPACER
M EMBRANE
SPIRAL MEMBRANE MODULE
POROUS SUPPORT TUBE
WITH MEMBRANE
PRODUCT WATER
PERMEATE FLOW
.',•* BRACKISH
WATER
TEED FLOW
I i | . > ' • j « •
PRODUCT WATER
TUBULAR REVERSE OSMOSIS MODULE
BRINE
CONCENTRATE
FLOW
SNAP
RING
OPEN ENDS
OF FIBERS
r— EPOXY
TUBE SHEET
POROUS
BACK-UP DISC
CONCENTRATE
OUTLET
•END PLATE
SHELL
•1BER
POROUS FEED
DISTRIBUTOR TUBE
J"0" RING\i 1
S£AL 1 \_
PERMEATE
END PLATE
HOLLOW FIBER MODULE
Figure VII-27
REVERSE OSMOSIS MEMBRANE CONFIGURATIONS
343
-------
iJ
T?
|i
u
Ii
1
] n t
it I
ji
ji
l1
1
il
3 II
•li
J^
«-IN. VITRIF1E
.1 U U L-
TP
1
1
] i
T 1
J^,
.D PIPE LAIO-^'
WITH PLASTIC JOINTS
^ !' i!
1
u
u
u
i
u
1 1
3 |i t
il
^-SPLASH BOX
\ M r
UJ !
? Il \
11
il
1'
jj
i U t
n
i
i s
Q
ir
n
1 n
? s !!
a. 0 ij
r 5 t ' ' T
<» 3 U
J^
^P
l'
r i i
i
i
i
ij
* i
1 1 1 D
^
l|
1
( I' r
I3 U C
II
1]
|l
U
J II C
II
-Jk
"""if
I
i t
i
n
1!
II t
«-
-------
ULTRAPILTRATION
P» 10-$ 0 PSl
MEMBRANE
WATER SALTS
•MEMBRANE
PERMEATE
' • •
• • •
•»
0 •
PEED
• •
. .
OA • •
• • o . .
O CONCENTRATE
•" * *Q * •
O .0
•I-- I-
-
•
• •
f
O OIL PARTICLES
• DISSOLVED SALTS AND LOW-MOLECULAR-WEIGHT ORCANICS
Figure VII-29
SIMPLIFIED ULTRAFILTRATION FLOW SCHEMATIC
345
-------
FABRIC OR WIRE
FILTER MEDIA
STRETCHED OVER
REVOLVING DRUM
ROLLER
SOLIDS SCRAPED
OFF FILTER MEDIA
DIRECTION OF ROTATION
LIQUID
THROUGH
MEDIA BY
MEANS OF
VACUUM
SOLIDS COLLECTION
HOPPER '
INLET LIQUID
TO 3£
FILTERED
-TROUGH
FILTERED LIQUID
Figure VII-30
VACUUM FILTRATION
346
-------
EVAPORATION
CONTACT COOLING
WATER
COOLING
TOWER
SLOWDOWN
DISCHARGE
RECYCLED FLOW
MAKE-UP WATER
Figure VII-31
FLOW DIAGRAM FOR RECYCLING WITH A COOLING TOWER
347
-------
SECTION VIII
COST OF WASTEWATER TREATMENT AND CONTROL
This section contains a summary of cost estimates, a discussion
of the cost methodology used to develop these estimates, and
descriptions of the equipment and assumptions for each individual
treatment technology. These cost estimates, together with the
estimated pollutant reduction performance for each treatment and
control option presented in Sections IX, X, XI, and XII of the
subcategory supplements, provide a basis for evaluating each
regulatory option. The cost estimates also provide the basis for
determining the probable economic impact of regulation on the
category at different pollutant discharge levels. In addition,
this section addresses nonwater quality environmental impacts of
wastewater treatment and control alternatives, including air
pollution, solid wastes, and energy requirements.
SUMMARY OF COST ESTIMATES
The total capital and annual costs of compliance with the pro-
posed regulation are presented by subcategory in Tables VIII-1
through VIII-3, pages 391 to 393, for regulatory options BPT,
BAT, and PSES, respectively. The number of direct and indirect
discharging plants in each subcategory is also shown. The cost
estimation methodology used to obtain these plant cost estimates
is described in the following sections.
COST ESTIMATION METHODOLOGY
Two general approaches to cost estimation are possible. The
first is a plant-by-plant approach in which costs are estimated
for each individual plant in the category. Alternatively, in a
model plant approach, costs can be projected for an entire cate-
gory (or subcategory) based on cost estimates for an appropri-
ately selected subset of plants. The plant-by-plant cost estima-
tion procedure is usually more accurate compared with the model
plant approach because it affords a higher degree of flexibility
and maximizes the use of plant specific data. For the nonferrous
metals phase II category, the plant-by-plant approach was
adopted.
To implement the selected approach, the wastewater characteris-
tics and appropriate treatment technologies for the category are
identified. These are discussed in Section V of each subcategory
supplement and Section VII of this document, respectively. Based
on a preliminary technical and economic evaluation, the model
treatment systems are developed for each regulatory option from
349
-------
the available set of treatment processes. When these systems are
established, a cost data base is developed containing capital and
operating costs for each applicable technology. To apply this
data base to each plant for cost estimation, the following steps
are taken:
1. Define the components of the treatment system (e.g.,
chemical precipitation, multimedia filtration) that are
applicable to the waste streams under consideration at
the plant and their sequence.
2. Define the flows and pollutant concentrations of the
waste streams entering the treatment system.
3. Estimate capital and annual costs for this treatment
system.
4. Estimate the actual compliance costs by accounting for
existing treatment in-place.
5. Repeat steps 1-4 for each regulatory option.
Because of the large number of plants in the category and to pro-
vide a greater degree of accuracy, the above steps are accom-
plished by development of a computer-based cost estimation model
for the nonferrous metals manufacturing category and related
categories with similar treatment technology. This model repre-
sents the key element in the plant-by-plant cost estimation
approach.
Each of the steps involved in the cost estimation methodology as
outlined above is described in more detail below.
Cost Data Base Development
A preliminary step required prior to cost estimation is the
development of a cost data base, which includes the compilation
of cost data and standardization of the data to a common dollar
basis. The components of the cost estimates, the sources of cost
data, and the update factors used for standardization (to March
1982 dollars in this case) are described below.
Components of Costs
The components of the capital and annual costs and the terminol-
ogy used in this study are presented here in order to ensure
unambiguous interpretation of the cost estimates and cost curves
included in this section.
350
-------
Capital Costs. The total capital costs consist of two major com-
ponents":direct, or total module capital costs and indirect, or
system capital costs. The direct capital costs include:
(1) Purchased equipment cost,
(2) Delivery charges (based on a shipping distance of 500
miles), and
(3) Installation (including labor, excavation, site work,
and materials).
The direct components of the total capital cost are derived
separately for each unit process, or treatment technology. In
this particular case, each unit process cost comprises individual
equipment costs (e.g., pumps, tanks, feed systems, etc.). The
correlating equations used to generate the individual equipment
costs are presented in Table VIII-4, page 394.
Indirect capital costs consist of contingency, engineering, and
contractor fees. These indirect costs are derived from factored
estimates, i.e., they are estimated as percentages of a subtotal
of the total capital cost, as shown in Table VIII-5, page 405.
Annual Costs. The total annualized costs also consist of a
direct and a system component as in the case of total capital
costs. The components of the total annualized costs are listed
in Table VIII-6, page 406. Direct annual costs include the
following:
• Raw materials - These costs are for chemicals and other
materials used in the treatment processes, which may
include lime, caustic, sodium sulfide, activated carbon,
sulfuric acid, ferrous sulfate, and polyelectrolyte.
• Operating labor and materials - These costs account for
the labor and materials directly associated with opera-
tion of the process equipment. Labor requirements are
estimated in terms of hours per year. A labor rate of
$21 per hour was used to convert the hour requirements
into an annual cost. This composite labor rate included
a base labor rate of $9 per hour for skilled labor, 15
percent of the base labor rate for supervision and plant
overhead at 100 percent of the total labor rate. The
base labor rate was obtained from the "Monthly Labor
Review," which is published by the Bureau of Labor
Statistics of the U.S. Department of Labor. For the
metals industry, this wage rate was approximately $9 per
hour in March of 1982.
351
-------
• Maintenance labor and materials - These costs account for
the labor and materials required for repair and routine
maintenance of the equipment. They are based on informa-
tion gathered from the open literature and from equipment
vendors.
• Energy - Energy, or power, costs are calculated based on
total energy requirements (in kw-hrs), an electricity
charge of $0.0483/kilowatt-hour and an operating schedule
of 24 hours/day, 250 days/year unless specified other-
wise. The electricity charge rate (March 1982) is based
on the average retail electricity prices charged for
industrial service by selected Class A privately-owned
utilities, as reported in the Department of Energy's
Monthly Energy Review.
System annual costs include monitoring, insurance and amortiza-
tion. Monitoring refers to the periodic analysis of wastewater
effluent samples to ensure that discharge limitations are being
met. The annual cost of monitoring was calculated using an
analytical lab fee of $120 per wastewater sample and a sampling
frequency based on the wastewater discharge rate, as shown in
Table VIII-7, page 407 . The values shown in Table VIII-7 repre-
sent typical requirements contained in NPDES permits. For the
economic impact analysis, the Agency also estimated monitoring
costs based on 10 samples per month, which is consistent with the
statistical basis for the monthly limit.
The cost of taxes and insurance is assumed to be one percent of
the total depreciable capital investment.
Amortization costs, which account for depreciation and the cost
of financing, were calculated using a capital recovery factor
(CRF). A CRF value of 0.177 was used, which is based on an
interest rate of 12 percent, and a taxable lifetime of 10 years.
The CRF is multiplied by the total depreciable investment to
obtain the annual amortization costs.
Standardization of Cost Data
All capital and annual cost data completed were standardized by
adjusting to March 1982 dollars based on the following cost
indices.
Capital Investment. Investment costs were adjusted using the
EPA-Sewage Treatment Plant Construction Cost Index. The value of
this index for March 1982 is 414.0.
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Chemicals. The Chemical Engineering Producer Price Index for
industrial chemicals is used. This index is published biweekly
in Chemical Engineering magazine. The March 1982 value of this
index is" 362. 67
Energy. Power costs are adjusted by using the price of electric-
ity on the desired date and multiplying it by the energy require-
ments for the treatment module in kw-hr equivalents. The indus-
trial charge rate for electricity for March 1982 is $0.0483 per
kw-hr as mentioned previously in the annual costs discussion.
Labor. Annual labor costs are adjusted by multiplying the hourly
labor rate by the labor requirements (in man-hours), if the
latter is known. The labor rate for March 1982 was assumed to be
21 dollars per hour (see above). In cases where the manhour
requirements are unknown, the annual labor costs are updated
using the EPA-Sewage Treatment Plant Construction Cost Index.
The value of this index for March 1982 is 414.0 as stated above.
Plant Specific Flowsheet
When the cost data base has been developed, the first step of the
cost estimation procedure is the selection of the appropriate
treatment technologies and their sequence for a particular plant.
These are determined for a given option by applying the general
treatment diagram for that subcategory to the plant. This gen-
eral option diagram is modified as appropriate to reflect the
treatment technologies that the plant will require. For
instance, one plant in a subcategory may generate wastewater from
a certain operation that requires oil/water separation. Another
plant in the same subcategory may not generate this waste stream
and thus does not require oil/water separation technology. The
specific plant flowsheets will reflect this difference.
Wastewater Characteristics
Upon establishing the flowsheet required for a given plant, the
next step is to define the influent waste stream characteristics
(flow and pollutant concentrations*).
The list of pollutants which are tracked by the computer model is
shown in Table VIII-8, page 408 . This list includes the conven-
tional pollutants and priority toxic metals pollutants that are
*Although some pollutant parameters are obviously not measurable
as concentration (pH, temperature), we shall use the term
inclusively.
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generally found in metal-bearing waste streams. Inclusion of
these pollutants allows the model to account for the effects of
varying influent concentrations upon the various wastewater
treatment processes. For example, influent waste streams with
high metals loadings require a greater volume of precipitant
(such as lime) and generate a greater amount of sludge than
wastestreams with lower metals concentrations. The cost model
can be modified as necessary to include pollutants that may be
present at significant levels or pollutants under consideration
for regulation in that subcategory. These pollutant concentra-
tions are calculated for each influent waste stream requiring
treatment.
The raw waste concentrations of pollutants present in the
influent waste streams for cost estimation were based primarily
on field sampling data. A production normalized raw waste value
in milligrams of pollutant per metric ton of production was cal-
culated for each pollutant by multiplying the measured concentra-
tion by the corresponding waste stream flow and dividing this
result by the corresponding production associated with generation
of the waste stream. These raw waste values are averaged across
all sampled plants where the waste stream is found. These final
raw waste values are used in the cost estimation procedure to
establish influent pollutant loadings to each plant's treatment
system. The underlying assumption in this approach is that the
amount of pollutant that is discharged by a process is a function
only of the amount of product that is generated by the process
(or in some cases, the amount of raw material used in the pro-
cess) . The amount of water used in the processes is assumed to
not affect on the pollutant discharged. This assumption is also
called the constant mass assumption since the mass of pollutant
discharged remains the same even if the flow of water carrying
the pollutant is changed. In reality, the amount of pollutant
discharged will often be somewhat less if less water is used in
the process. However, quantification of this relationship is not
possible without a large amount of data; therefore, the constant
mass assumption was chosen as a conservative approach.
The individual flows for cost estimation are determined for each
waste stream. The procedure used to derive these flows is as
follows:
(1) The production normalized flows (1/kkg) were determined
for each waste stream based on production (kkg/yr) and
current flow (1/yr) data obtained from each plant's dcp
or trip report data where possible.
(2) This flow was compared to the regulatory flow allowance
(1/kkg) established by the Agency for each waste
stream.
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(3) The lower of the two flows was selected as the cost
estimation flow. The flow in 1/yr is calculated by
multiplying the selected flow by the production
associated with that waste stream.
(4) The regulatory flow was assigned to waste streams for
which actual flow rate data were unavailable for a
plant.
Treatment System Cost Estimation
Once the treatment system and waste stream characteristics have
been defined, they can be used as input to the cost estimation
step, which is based on the cost estimation model and general
cost assumptions described below.
Cost Estimation Model
The computer-based cost estimation model was designed to provide
conceptual wastewater treatment design and cost estimates based
on wastewater flows, pollutant loadings, and unit operations that
are specified by the user. The model was developed using a modu-
lar approach, that is, individual wastewater treatment processes
such as gravity settling are contained in semi-independent
entities known as modules. These modules are used as building
blocks in the determination of the treatment system flow diagram.
Because this approach allows substantial flexibility in treatment
system cost estimation, the model did not require modification
for each regulatory option.
Each module was developed by coupling design information from the
technical literature with actual design data from operating
plants. This results in a more realistic design than using
either theoretical or actual data alone, and correspondingly more
accurate cost estimates. The fundamental units for cost estima-
tion are not the modules themselves but the components within
each module. These components range in configuration from a
single piece of equipment such as a pump to components with
several individual pieces, such as a lime feed system. Each com-
ponent is sized based on one or more fundamental parameters. For
instance, the lime feed system is sized by calculating the lime
dosage required to adjust the pH of the influent to 9 and precip-
itate dissolved pollutants. Thus, a larger feed system would be
designed for a chemical precipitation unit treating effluent
containing high concentrations of dissolved metals than for one
treating effluent of the same flow rate but lower metals load-
ings. This flexibility in design results in a treatment system
tailored to each plant's wastewater characteristics and corre-
spondingly more accurate compliance cost estimates.
The cost estimation model consists of four main parts, or
categories of programs:
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• User input programs,
• Design and simulation programs
• Cost estimation programs, and
• Auxiliary programs.
A general logic diagram depicting the overall calculational
sequence is shown in Figure VIII-1, page 415.
The user input programs allow entry of all data required by the
model, including the plant-specific flowsheet, flow and composi-
tion data for each waste stream, and specification of recycle
loops. The design portion of the model calculates the design
parameter for each module of the flowsheet based on the user
input and material balances performed around each module. Figure
VIII-2, page 416 , depicts the logic flow diagram for the design
portion of the model.
The design parameters are used as input to the cost estimation
programs to calculate the costs for each module equipment com-
ponent (individual correlating cost equations were developed for
each of these components). The total direct capital and annual
costs are equal to the sum of the module capital and annual
costs, respectively. System, or indirect costs (e.g., engineer-
ing, amortization) are then calculated (see Table VIII-5, page 405
, and Table VIII-6, page 406 ) and added to the total direct costs
to obtain the total system costs. The logic flow for the cost
estimation programs is displayed in Figure VIII-3, page 417. The
auxiliary programs store and transfer the final cost estimates to
data files, which are then used to generate final summary tables
(see Table VIII-10, page 411, for a sample summary table).
General Cost Assumptions
The following general assumptions apply to cost estimation in all
subcategories:
(1) Unless otherwise specified, all wastewater treatment
sludges are considered to be nonhazardous.
(2) In cases in which a single plant has wastewater gener-
ating processes associated with different nonferrous
phase II subcategories, costs are estimated for a
single treatment system. In most cases, the combined
treatment system costs are then apportioned between
subcategories on a flow-weighted basis since hydraulic
flow is the primary determinant of equipment size and
cost. It is possible, however, for the combined
treatment system to include a treatment module that is
required by only one of the associated subcategories.
In this case, the total costs for that particular
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module are included in the costs for the subcategory
which requires the module. Where the module in
question involves flow reduction, the costs are
apportioned based on an influent flow weighted basis.
Such cost apportioning is essentially only a book-
keeping exercise to allocate costs; the total costs
calculated for the plant remain the same.
(3) In most cases, where a plant has wastewater sources
from the nonferrous phase II category and a category
other than nonferrous manufacturing (for example, non-
ferrous forming) costs are calculated for segregating
these different wastewaters. The only exception is for
overlap plants between nonferrous phase I and nonfer-
rous phase II where costs were estimated based on com-
bined treatment; the costs were flow-apportioned to
each category. This means of cost estimation accounts
for the possibility that respective regulations for
each category are based on different technologies (and
may control different pollutants).
Consideration of Existing Treatment
The cost estimates calculated by the model represent "greenfield
costs" that do not account for equipment that plants may already
have in-place, i.e., these costs include existing treatment
equipment. In order to estimate the actual compliance cost
incurred by a plant to meet the effluent guidelines, "credit"
should be given to account for treatment in-place at that plant.
This was accomplished by subtracting capital costs of treatment
in-place (as estimated by the model) from the "greenfield costs"
to obtain the actual or required capital costs of compliance.
Annual costs associated with treatment in-place (as estimated by
the model); however, are not subtracted because these costs recur
and must be borne by the facility each year. Further, inclusion
of these annual costs ensures that EPA adequately considers the
costs for proper operation of each module in the treatment
system. For an example the reader is referred to Table VIII-10,
page 411, which presents compliance cost estimates for a plant
that has chemical precipitation and vacuum filtration of
sufficient capacity already in-place.
Existing treatment is considered as such only if the capacity and
performance of the existing equipment (measured in terms of esti-
mated ability to meet the proposed effluent limitations) is
equivalent to that of the technologies considered by the Agency.
The primary source of information regarding existing treatment
was data collection portfolios (dcp's).
General assumptions applying to all subcategories used for deter-
mining treatment in-place qualifications in specific instances
include:
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(1) In cases in which existing equipment has adequate per-
formance but insufficient capacity, the plant is
assumed to comply by either installing additional
required capacity to supplement the existing equipment
or disregarding the existing equipment and installing
new equipment to treat the entire flow. This selection
was based on the lowest total annualized cost.
(2) When a plant reported recycle of treatment plant
sludges, capital and annual costs for sludge handling
(vacuum filtration and contract hauling) are not
included in the compliance costs. It is assumed that
it is economical for the plant to practice recycle in
this case, and therefore, the related costs are consid-
ered to be process associated, or a cost of doing
business.
(3) Capital costs for flow reduction (via recycling) were
not included in the compliance costs whenever the plant
reported recycle of the stream, even if the specific
method of recycle was not reported.
(4) Settling lagoons were assumed to be equivalent to
vacuum filtration for dewatering treatment plant
sludges. Thus, whenever a plant reported settling
lagoons to be currently in use for treatment plant
sludges, the capital costs of vacuum filtration were
not included. It was assumed that annual vacuum
filtration costs were comparable to those for operation
of settling lagoons and were thus retained.
COST ESTIMATES FOR INDIVIDUAL TREATMENT TECHNOLOGIES
Treatment technologies have been selected from among the larger
set of available alternatives discussed in Section VII after
considering such factors as raw waste characteristics, typical
plant characteristics (e.g., location, production schedules,
product mix, and land availability), and present treatment
practices. Specific rationale for selection is addressed in
Sections IX, X, XI, and XII of this document and the subcategory
supplements. Cost estimates for each technology addressed in
this section include investment costs and annual costs for
amortization, operation and maintenance, and energy.
The specific design and cost assumptions for each wastewater
treatment module are listed under the subheadings to follow.
Costs are presented as a function of influent wastewater flow
except where noted in the unit process assumptions.
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Costs are presented for the following control and treatment tech-
nologies:
- Cooling towers,
Flow equalization,
- Cyanide precipitation and gravity settling,
- Ammonia steam stripping,
- Oil/water separation,
- Chemical precipitation and gravity settling,
Sulfide precipitation and gravity settling,
- Vacuum filtration,
Holding tanks,
- Multimedia filtration,
Activated carbon adsorption,
- Chemical oxidation, and
Contract hauling.
In addition, costs for the following items associated with com-
pliance costs are also discussed:
- Enclosures
Segregation
Cooling Towers
Cooling towers are used to reduce discharge flows by recycling
cooling water waste streams. Holding tanks are used to recycle
flows less than 3,400 liters per hour (15 gpm). This flow repre-
sents the effective minimum cooling tower capacity generally
available.
The cooling tower capacity is based on the amount of heat
removed, which takes into account both the design flow and the
temperature decrease needed across the cooling tower. The influ-
ent flow to the cooling tower and the recycle rate are based on
the assumptions given in Table VIII-9, page 410 . it should be
noted that for BAT a cooling tower is not included for cases in
which the actual flow is less than the reduced regulatory flow
(BAT flow) since flow reduction is not required.
The temperature decrease is calculated as the difference between
the hot water (inlet) and cold water (outlet) temperatures. The
cold water temperature was assumed to be 29°C (85°F) and an aver-
age value calculated from sampling data is used as the hot water
temperature for a particular waste stream. When such data were
unavailable, or resulted in a temperature less than 35°C (95°F),
a value of 35°C (95°F) was assumed, resulting in a cooling
requirement for a 6°C (10°F) temperature drop. The other two
design parameters, namely the wet bulb temperature (i.e., ambient
temperature at 100 percent relative humidity) and the approach
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(the difference between the outlet water temperature and the wet
bulb temperature), were assumed to be constant at 25°C (77°F) and
4°C (8°F), respectively.
For flow rates above 3,400 1/hr, a cooling tower is designed.
The cooling tower is sized by calculating the required capacity
in evaporative tons. Cost data were gathered for cooling towers
up to 700 evaporative tons.
The capital costs of cooling tower systems include the following
equipment:
Cooling tower (crossflow, mechanically-induced) and
typical accessories
Piping and valves (305 meters (1,000 ft.), carbon
steel)
Cold water storage tank (1-hour retention time)
Recirculation pump, centrifugal
Chemical treatment system (for pH, slime and corrosion
control)
For heat removal requirements exceeding 700 evaporative tons,
multiple cooling towers are designed.
The direct capital costs include purchased equipment cost, deliv-
ery, and installation. Installation costs for cooling towers are
assumed to be 200 percent of the cooling tower cost based on
information supplied by vendors.
Direct annual costs include raw chemicals for water treatment and
fan energy requirements. Maintenance and operating labor was
assumed to be constant at 60 hours per year. The water treatment
chemical cost is based on a rate of $220/1,000 Iph ($5/gpm) of
recirculated water.
For small recirculating flows (less than 15 gpm), holding tanks
were used for recycling cooling water. A holding tank system
consists of a steel tank, 61 meters (200 feet) piping, and a
recirculation pump. The capacity of the holding tank is based on
the cooling requirements of the water to be cooled. Calculation
of the tank volume is based on a surface area requirement of
0.025 m^/lph (60 ft^/gpm) of recirculated flow and constant
relative tank dimensions.
Capital costs for the holding tank system include purchased
equipment cost, delivery, and installation. The annual costs are
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attributable to the operation of the pump only (i.e., annual
costs for tank and piping are assumed to be negligible).
Capital and annual costs for cooling towers and tanks are pre-
sented in Figure VIII-4, page 41 8.
Flow Equalization
Flow equalization is accomplished through steel equalization
tanks which are sized based on a retention time of 8 or 16 hours
and an excess capacity factor of 1 . 2. A retention time of 16
hours was assumed only when the equalization tank preceded a
chemical precipitation system with "low flow" mode, and the
operating hours were greater than or equal to 16 hours per day.
In this case, the additional retention time is required to hold
wastewater during batch treatment, since treatment is assumed to
require 1 6 hours and only one reaction tank is included in the
"low flow" batch mode. Cost data were available for steel
equalization tank up to a capacity of 1,893,000 liters (500,000
gallons) ; multiple units were required for volumes greater than
1,893,000 liters (500,000 gallons). The tanks are fitted with
agitators with a horsepower requirement of 0.006 kw/ 1,000 liters
(0.03 hp/1,000 gallons) of capacity to prevent sedimentation. An
influent transfer pump is also included in the equalization
system. Cost curves for capital and annual costs are presented
in Figure VIII-5, page 419 , for equalization at 8 hours and 16
hours retention time.
Cyanide Precipitation and Gravity Settling
Cyanide precipitation is a two-stage process to remove complexed
and uncomplexed cyanide as a precipitate. In the first step, the
wastewater is contacted with an excess of FeSC-4* 7H£0 at pH
9.0 to ensure that all cyanide is converted to the complexed
form:
FeS04-7H20 + 6CN~ •> Fe(CN)g3- + 7H20 + S042' + e~
The hexacyanoferrate is then routed to the second stage, where
additional FeS04« 7H20 and acid are added. In this stage,
the pH is lowered to 4.0 or less, causing the precipitation of
Fe3(Fe(CN)g)2 (Turnbull's blue) and its analogues:
3FeS04-7H20 + 2Fe(CN)63~ -* Fe3(Fe(CN)6)2 + 21H20 + 3S042'
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The blue precipitate is settled and the overflow is discharged
for further treatment.
Since the complexation step adjusts the pH to 9, metal hydroxides
will precipitate. These hydroxides may either be settled and
removed at pH 9 or resolubilized at pH 4 in the final precipita-
tion step and removed later in a downstream chemical precipita-
tion unit. Advantages of removal of the metal hydroxides include
reduced acid requirements in the final precipitation step, since
the metals will resolubilize when the pH is adjusted to 4.
However, the hydroxide sludge may be classified as hazardous due
to the presence of cyanide. In addition, the continuous mode of
operation requires an additional clarifier between the complexa-
tion and precipitation step. These additional costs make the
settling of metal hydroxides economically unattractive in the
continuous mode. However, the batch mode requires no extra
equipment. Consequently, metal hydroxide sludge removal in this
case is desirable before the precipitation step. Therefore, the
batch cyanide precipitation step settles two sludges: metal
hydroxide sludge (at pH 9) and cyanide sludge (at pH 4).
Costs were estimated for both batch and continuous systems with
the operating mode selected on a.least cost basis. The equipment
and assumptions used in each mode are detailed below.
Costs for the complexation step in the continuous mode are based
on the following:
(1) Ferrous sulfate feed system
ferrous sulfate steel storage hoppers with dust
collectors (largest hopper size is 170 m3
(6,000 ft3); 15 days storage)
enclosure for storage tanks
volumetric feeders (small installations)
mechanical weigh belt feeders (large installations)
dissolving tanks (5-minute detention time, 6 percent
solution)
dual-head diaphragm metering pumps
instrumentation and controls
(2) Lime feed system
- hydrated lime
feeder
- slurry mix tank (5-minute retention time)
- feed pump
instrumentation (pH control)
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(3) H£S04 feed system (used when influent pH is >9)
93 percent i^SO^ delivered in bulk or in drums
- acid storage tank (15 days retention) when delivered
in bulk
metering pump (standby provided)
pipe and valves
instrumentation and controls
(4) Reaction tank and agitator (fiberglass, 60-minute
retention time, 20 percent excess capacity, agitator
mount, concrete slab)
(5) Effluent transfer pump
Costs for the second step (precipitation) in the continuous mode
are based on the following equipment:
(1) FeSO^ feed system - as above
(2) H2S04 feed system - as above
(3) Polymer feed system
storage hopper
chemical mix tank witn agitator
- chemical metering pump
(4) Reaction tank with agitator (fiberglass, 30-minute
retention time, 20 percent excess capacity, agitator
mount, concrete slab)
(5) Clarifier
- sized based on 709 lph/m2 (17.4 gph/ft2) , 3
percent solids in underflow
steel or concrete, above ground
support structure, sludge scraper, and other
internals
center feed
(6) Effluent transfer pump
(7) Sludge transfer pump
Operation and maintenance costs for continuous mode cyanide pre-
cipitation include labor requirements to operate and maintain the
system, electric power for mixers, pumps, clarifier and controls,
and treatment chemicals. Electrical requirements are also
included for the chemical storage enclosures for lighting and
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ventilation and in the case of caustic storage, heating. The
following assumptions are used in establishing O&M costs for the
complexation step in the continuous mode:
(1) Ferrous sulfate feed system
stoichiometry of 1 mole FeSOA-7HoO to 6 moles
CN-
1.5 times stoichiometric dosage to drive reaction to
completion
- operating labor at 10 min/feeder/shift
maintenance labor at 8 hr/yr for liquid metering
pumps
power based on agitators, metering pumps
maintenance materials at 3 percent of capital cost
- chemical cost at $0.1268 per kg ($0.0575 per Ib)
(2) Lime feed system
dosage based on pH and metals content to raise pH
to 9
operating and maintenance labor requirements are
based on 20 min/day; in addition, 8 hr/7,260 kg
(8 hr/16,000 Ibs) are assumed for delivery of
hydrated lime
maintenance materials cost is estimated as 3 percent
of the purchased equipment cost
chemical cost of lime is based on $0.0474/kg
($0.0215 per Ib) for hydrated lime delivered in bags
(3) Acid feed system (if required)
dosage based on pH and metals to bring pH to 9
labor unloading - 0.25 hr/drum acid
labor operation - 15 min/day
annual maintenance - 8 hrs
power (includes metering pump)
maintenance materials - 3 percent of capital cost
- chemical cost at $0.082 per kg ($0.037 per Ib)
(4) Reaction tank with agitator
maintenance materials
tank: 2 percent of tank capital cost
pump: 5 percent of pump capital cost
power based on agitator (70 percent efficiency)
at 0.099 kW/1,000 liters (0.5 hp/1,000 gallons)
of tank volume
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(5) Pump
operating labor at 0.04 hr/operating day
maintenance labor at 0.005 hr/operating hour for
flow < 22,700 liters per hour (100 gpm)
maintenance materials at 5 percent of capital cost
power based on pump hp
The following assumptions were used for the continuous mode
precipitation step:
(1) Ferrous sulfate feed system
stoichiometric dosage based on 3 moles
FeS04« 7H?0 to 2 moles of iron-complexed
cyanide (Fe(CN)63~)
total dosage is 10 times stoichiometric dosage
based on data from an Agency treatability study
other assumptions as above
(2) H2S04 feed system
dosage based on pH adjustment to 4 and resolubiliza-
tion of the metal hydroxides from the complexation
step
- other assumptions as above
(3) Polymer feed system
2 mg/1 dosage
operation labor at 134 hr/yr, maintenance labor at
32 hr/yr
maintenance materials at 3 percent of the capital
cost
- energy at 17,300 kWh/yr
- chemical cost at $4.96/tcg ($2.25/lb)
(4) Reaction tank with agitator
see assumptions above
(5) Clarifier
maintenance materials range from 0.8 percent to
2 percent as a function of increasing size
labor - 150 to 500 hr/yr (depending on size)
power - based on horsepower requirements for sludge
pumping and sludge scraper drive unit
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(6) Effluent transfer pump
see assumptions above
(7) Sludge pump
sized on underflow from clarifier
operation and maintenance labor varies with flow
rate
maintenance materials - varies from 7 percent to
10 percent of capital cost depending on flow rate
The batch mode cyanide precipitation step accomplishes both
complexation and precipitation in the same vessel. Costs for
batch mode cyanide complexation and precipitation are based on
the following equipment:
(1) Ferrous sulfate addition
from bags
added manually to reaction tank
(2) Lime addition
from bags
added manually to reaction tank
(3) H2S04 addition
- from 208 liter (55 gallon) drums
stainless steel valve to control flow
(4) Reaction tank and agitator (fiberglass, 8.5 hour
minimum retention time, 20 percent excess capacity,
agitator mount, concrete slab)
(5) Pump
effluent transfer pump
sludge pump
Operation and maintenance costs for batch mode cyanide complexa-
tion and precipitation include costs for the labor required to
operate and maintain the equipment, electrical power for
agitators, pumps, and controls, and chemicals. The assumptions
used in estimating costs are as follows:
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(1) Ferrous sulfate addition
stoichiometric dosage
--complexation: 1 mole FeS04«7H£0 per 6 moles
CN-
—precipitation: 3 moles FeSC^-7^0 per 2
moles of the iron cyanide complex (F
actual dosage in excess of stoichiometric
--complexation: 1.5 times stoichiometric dosage
added
--precipitation: 10 times stoichiometric dosage
added
- operating labor at 0.25 hr/batch
- chemical cost at $0.1268/kg ($0.0575/lb)
no maintenance labor or materials or power costs
(2) Lime addition
dosage based on pH and metals content to raise pH
to 9
- operating labor at 0.25 hr/batch
- chemical cost at $0.0474/kg ($0.0215/lb)
no maintenance labor or materials or power costs
(3) H2S04 addition
dosage based on pH and metals content to lower pH
to 9 (for complexation if required) and/or to lower
pH to 4 (for precipitation)
operating labor at 0.25 hr/batch
- chemical cost at $0.082/kg ($0.037/lb)
no maintenance labor or materials or power costs
(4) Reaction tank with agitator
maintenance materials
--tank: 2 percent of tank capital cost
—pump: 5 percent of pump capital cost
power based on agitator (70 percent efficiency) at
0.099 kW/1,000 liters (0.5 hp/1,000 gallons) of tank
volume
(5) Pumps
- effluent transfer pump
—operating labor at 0.04 hr/operating day
--maintenance labor at 0.005 hr/operating day (or
flows < 22,700 1/hr (100 gpm)
--maintenance materials at 5 percent of capital cost
--power based on pump hp
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- sludge pump
—operation and maintenance costs vary with flow
rate
--maintenance materials costs vary from 7 to 10 per-
cent of capital cost depending on flow rate
Capital and annual costs for continuous and batch mode cyanide
precipitation are presented in Figure VIII-6, page 420 .
Ammonia Steam Stripping
Ammonia removal using steam is a proven technology that is in use
in many industries. Ammonia is more volatile than water and may
be removed using steam to raise the temperature and preferenti-
ally evaporate the ammonia. This process is most economically
done in a plate or packed tower, where the method of contacting
the liquid and vapor phases reduces the steam requirement.
The pH of the influent wastewater is raised to approximately 12
to convert almost all of the ammonia present to molecular ammonia
(NH3) by the addition of lime. The water is then preheated
before it is sent to the column. This process takes place by
indirectly contacting the influent with the column effluent and
with the gaseous product via heat exchangers. The water enters
the top of the column and travels downward. The steam is
injected at the bottom and rises through the column, contacting
the water in a countercurrent fashion. The source of the steam
may be either reboiled wastewater or another steam generation
system, such as the plant boiler system.
The presence of solids in the wastewater, both those present in
the influent and those which may be generated by adjusting the pH
(such as metal hydroxides), necessitates periodic cleaning of the
column. This requires an acid cleaning system and a surge tank
to hold wastewater while the column is being cleaned. The column
is assumed to require cleaning approximately once per week based
on the demonstrated long-term cleaning requirements of an ammonia
stripping facility. The volume of cleaning solution used per
cleaning operation is assumed to be equal to the total volume of
the empty column (i.e., without packing).
For the estimation of capital and annual costs, the following
pieces of equipment were included in the design of the steam
stripper:
(1) Packed tower
3-inch Rashig rings
- hydraulic loading rate = 2 gpm/ft^
- height equivalent to a theoretical plate = 3 ft
368
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(2) pH adjustment system
lime feed system (continuous) - see chemical precip-
itation section for discussion
- rapid mix tank, fiberglass (5-minute retention time)
- agitator (velocity gradient is 300 ft/sec/ft)
control system
pump
(3) Heat exchangers (stainless steel)
(4) Reboiler (gas-fired)
(5) Acid cleaning system
- batch tank, fiberglass
agitator (velocity gradient is 60/sec.)
metering pump
(6) Surge tank (8-hour retention time)
The direct capital cost of the lime feed system was based on the
chemical feed rate as noted in the discussion on chemical precip-
itation. Sulfuric acid used in the acid cleaning system was
assumed to be added manually, requiring no special equipment.
Other equipment costs were direct or indirect functions of the
influent flow rate. Direct annual costs include operation and
maintenance labor for the lime feed system, heat exchangers and
reboiler, the cost of lime and sulfuric acid, maintenance mate-
rials, energy costs required to run the agitators and pumps, and
natural gas costs to operate the reboiler. The total direct cap-
ital and annual costs are presented in Figure VIII-7, page 421 .
Oil/Water Separation
Oil skimming costs apply to the removal of free (non-emulsified)
oil using either a coalescent plate oil/water separator or a belt
skimmer located on the equalization tank. The latter is applica-
ble to low oily waste flows (less than 189 liters per day)
whereas the coalescent plate separator is used for oily flows
greater than 189 liters/day (50 gpd)'.
Although the required coalescent plate separator capacity is
dependent on many factors, the sizing was based primarily on the
influent wastewater flow rate, with the following design values
assumed for the remaining parameters of importance:
369
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Parameter Design Value
Specific gravity of oil 0.85
Operating temperature (°F) 68
Influent oil concentration (mg/1) 30,000
Effluent oil concentration (mg/1) 10.0
Extreme operating conditions, such as influent oil concentrations
greater than 30,000 mg/1, or temperatures much lower than 20°C
(68°F) were accounted for in the sizing of the separator. Addi-
tional capacity for such extreme conditions was provided using
correlations developed from actual oil separator performance
data.
The capital and annual costs of oil/water separation include the
following equipment:
Coalescent plate separator with automatic shutoff valve
and level sensor
Oily waste storage tanks (2-week retention time)
Oily waste discharge pump
- Effluent discharge pump
Influent flow rates up to 159,100 1/hr (700 gpm) are treated in a
single unit; flows greater than this require multiple units.
The direct annual costs for oil/water separation include the cost
of operating and maintenance labor and replacement parts. Annual
costs for the coalescent plate separators alone are minimal and
involve only periodic cleaning and replacement of the plates.
If the amount of oil discharged is 189 liters/day (50 gpd) or
less, it is more economical to use a belt skimmer rather than a
coalescent plate separator. This belt skimmer may be attached to
the equalization basin which is usually necessary to levelize
flow surges. The belt skimmer/equalization basin configuration
is assumed to achieve 10 mg/1 oil in the effluent.
The equipment included in the belt oil skimmer and associated
design parameters and assumptions are presented below.
1. Belt oil skimmer
12 inch width
6 foot length
2. Oily waste storage tank
2 week storage
fiberglass
370
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Capital costs for belt skimmers were obtained from published
vendor quotes. Annual costs were estimated from the energy and
operation and maintenance requirements. Energy requirements are
calculated from the skimmer motor horsepower. Operating labor is
assumed constant at 26 hours per year. Maintenance labor is
assumed to require 24 labor hours per year and belt replacement
once a year. Cost curves for capital and annual costs of
oil/water separation are presented in Figure VIII-8, page 422.
Since the oil removal rate was less than 189 liters/day (50 gpd)
for all plants in this category requiring oil/water separation,
only the costs for belt-type oil skimmers are presented.
Chemical Precipitation and Gravity Settling
Chemical precipitation using lime or caustic followed by gravity
settling is a fundamental technology for metals removal. In
practice, quicklime (CaO), hydrated lime [Ca(OH)2l, or caustic
(NaOH) can be used to precipitate toxic and other metals. Where
lime is selected, hydrated lime is generally more economical for
low lime requirements since the use of slakers, which are neces-
sary for quicklime usage, is practical only for large volume
applications of lime (greater than 50 Ibs/hr). The chemical
precipitant used for compliance costs estimation depends on a
variety of factors and the subcategory being considered. The
basis for the chemical precipitant (lime or caustic) used for a
particular subcategory may be found in the appropriate
supplement.
Lime or caustic is used to adjust the pH of the influent waste
stream to a value of approximately 9, at which optimum overall
precipitation of the metals as metal hydroxides is assumed to
occur. The chemical precipitant dosage is calculated as a
theoretical stoichiometric requirement based on the pH and the
influent metals concentrations. In addition, particular waste
streams may contain significant amounts of fluoride, such as
those found in the secondary tin subcategory. The fluoride will
form calcium fluoride (CaF£) when combined with free calcium
ions which are present if lime is used as the chemical precipi-
tant. The additional sludge due to calcium fluoride formation is
included in the sludge generation calculations. In cases where
the calcium consumed by calcium fluoride formation exceeds the
calcium level resulting from dosing for pH adjustment and metal
hydroxide formation, the additional lime needed to consume the
remaining fluoride is included in the total theoretical dosage
calculation. The total chemical dosage requirement is obtained
by assuming an excess of 10 percent of the theoretical dosage.
The effluent concentrations are generally based on the Agency's
combined metals data base treatment effectiveness values for
chemical precipitation technology described in Section VII (see
Table VII-XX, page 311.
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The costs of chemical precipitation and gravity settling are
based on one of three operating modes, depending on the influent
flow: continuous, "normal" batch, or "low flow" batch. The use
of a particular mode for cost estimation purposes is determined
on a least cost (total annualized) basis. The economic break-
point between continuous and normal batch was estimated to be
10,600 1/hr (46.7 gpm). Below 2,200 1/hr, it was found that the
low flow batch was the most economical. The direct capital and
annual costs are presented in Figure VIII-9, page423 for all
three operating modes.
Continuous Mode. For continuous operation, the following equip-
ment is included in the determination of capital and annual
costs:
(1) Chemical precipitant feed system (continuous)
lime
--bags (for hydrated lime) or storage units (30-day
storage capacity) for quicklime
—slurry mix tank (5-minute retention time) or
slaker
--feed pumps (for hydrated lime slurry) or gravity
feed (for quicklime slurry)
--instrumentation (pH control)
caustic
--day tanks (2) with mixers and feeders for feed
rates less than 200 Ibs/day; fiberglass tank with
15-day storage capacity otherwise
--chemical metering pumps
--pipe and valves
—instrumentation (pH control)
(2) Polymer feed system
- storage hopper
chemical mix tank with agitator
chemical metering pump
(3) Reaction system
rapid mix tank, fiberglass (5-minute retention time)
agitator (velocity gradient is 300 ft/sec/ft)
instrumentation and control
(4) Gravity settling system
- clarifier, circular, steel (overflow rate is 500
gpd/ft.2; underflow solids is 3 percent)
(5) Sludge pump
372
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Ten percent of the clarifier underflow stream is recycled to the
pH adjustment tank to serve as seed material for the incoming
waste stream.
The direct capital costs of the chemical precipitant and polymer
feed are based on the respective feed rates (dry Ibs/hr), which
are dependent on the influent waste stream characteristics. The
flexibility of this feature (i.e., costs are independent of other
module components) was previously noted in the description of the
cost estimation model. The remaining equipment costs (e.g., for
tanks, agitators, pumps) were developed as a function of the
influent flow (either directly or indirectly, when coupled with
the design assumptions).
Direct annual costs for the continuous system are based on the
following assumptions:
(1) Lime feed system
Operating and maintenance labor requirements are
based on 3 hrs/day for the quicklime feed system and
20 min/day for the hydrated lime feed system. In
addition, 5 hrs/50,000 Ibs are required for bulk
delivery of quicklime and 8 hrs/16,000 Ibs are
assumed for delivery of hydrated lime.
Maintenance materials cost is estimated as 3 percent
of the purchased equipment cost.
- Chemical cost of lime is based on $47.40/kkg
($43.00/ton) for hydrated lime delivered in bags and
$34.50/kkg ($31.30/ton) for quicklime delivered on a
bulk basis. These costs were obtained from the
Chemical Weekly Reporter (March 1982).
(2) Caustic feed system
Labor for unloading of dry NaOH requires 8 hours per
16,000 Ibs delivered. Liquid 50 percent NaOH
requires 5 hours per 50,000 Ibs.
Operating labor for dry NaOH feeders is 10
min/day/feeder
Operating labor for metering pump is 15 min/day
Maintenance materials cost is assumed to be 3
percent of the purchased equipment cost.
Maintenance labor requires 8 hours per year.
Energy cost is based on the horsepower requirements
for the feed pumps and mixers. Energy requirements
generally represent less than 5 percent of the total
annual costs for the caustic feed system.
- Chemical cost is $0.183 per Ib.
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(3) Polymer feed system
Polymer requirements are based on a dosage of 2
mg/1.
The operating labor is assumed to be 134 hrs/yr,
which includes delivery and solution preparation
requirements. Maintenance labor is estimated at 32
hrs/yr.
Energy costs for the feed pump and mixer are based
on 17,300 kw-hr/yr.
- Chemical cost for polymer is based on $5.00/kkg
($2.25/lb).
(4) Reaction system
Operating and maintenance labor requirements are 120
hrs/yr.
Pumps are assumed to require 0.005 hrs of mainte-
nance/operating hr (for flows less than 100 gpm)
or 0.01 hrs/operating hr (flows greater than 100
gpm), in addition to 0.05 hrs/operating day for
pump operation.
- Maintenance materials costs are estimated as 5
percent of the purchased equipment cost.
Energy costs are based on the power requirements for
the pump (function of flow) and agitator (0.06 hp/
1,000 gal). An agitator efficiency of 70 percent
was assumed.
(5) Gravity settling system
Annual operating and maintenance labor requirements
range from 150 hrs for the minimum size clarifier
(300 ft.2) to 500 hrs for a clarifier of 30,000
ft.2. In addition, labor hrs for operation and
maintenance of the sludge pumps were assumed to
range from 55 to 420 hrs/yr, depending on the pump
capacity (10 to 1,500 gpm).
- Maintenance material costs are estimated as 3
percent of the purchased equipment cost.
Energy costs are based on power requirements for the
sludge pump and rake mechanism.
Normal Batch Mode. The normal batch treatment system, which is
used for flows between 2,200 and 10,600 1/hr, consists of the
following equipment:
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(1) Chemical precipitant feed system
lime (batch)
--slurry tank (5-minute retention time)
--agitator
--feed pump
caustic (batch)
—fiberglass tank (1-week storage)
--chemical metering pump
(2) Polymer feed system (batch)
chemical mix tank (5-day retention tank)
agitator
chemical metering pump
(3) Reaction system
reaction tanks (minumum of 2) (8-hour retention
time each)
agitators (2) (velocity gradient is 300 ft/sec/ft)
pH control system
The reaction tanks used for pH adjustment are sized to hold the
wastewater volume accumulated for one batch period (assumed to be
8 hours). The tanks are arranged in a parallel setup to allow
treatment in one tank while wastewater is accumulated in the
other tank. A separate gravity settler is not necessary since
settling can occur in the reaction tank after precipitation has
taken place. The settled sludge is then pumped to the dewatering
stage if necessary.
Direct annual costs for the normal batch treatment system are
based on the following assumptions:
(1) Lime feed system (batch)
Operating labor requirements range from 15 to 60
min/batch, depending on the feedrate (5 to 1,000 Ibs
of hydrated lime/batch).
Maintenance labor is assumed to be constant at 52
hrs/yr (1 hr/week).
Energy costs for the agitator and feed pump are
assumed to be negligible.
Chemical costs are based on the use of hydrated lime
(see continuous feed system assumptions).
(2) Caustic feed system (batch)
- Operating labor requirements are based on 30
min/metering pump/shift.
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- Maintenance labor requirements are 16 hrs/metering
pump/yr.
Energy costs are assumed to be negligible.
- Chemical costs are based on the use of 50 percent
liquid caustic solution (see continuous feed
system).
(3) Polymer feed system (batch)
Polymer requirements are based on a dosage of
2 ing/1.
Operating and maintenance labor are assumed to
require 50 hrs/yr.
Chemical cost for polymer is based on $5.00/kkg
($2.25/lb).
(4) Reaction system
Required operating labor is assumed to be 1 hr/batch
(for pH control, sampling, valve operation, etc.).
Maintenance labor requirements are 52 hrs/yr.
Energy costs are based on power requirements for
operation of the sludge pump and agitators.
Low-Flow Batch Mode. For small influent flows (less than 2,200
1/hr),it is more economical on a total annualized cost basis to
select the "low flow" batch treatment system. The lower flows
allow an assumption of up to five days for the batch duration, or
holding time, as opposed to eight hours for the normal batch
system. However, whenever the total batch volume (based on a
five day holding time) exceeds 10,000 gallons, which is the
maximum single batch tank capacity, the holding time is decreased
accordingly to maintain the batch volume under this level. Capi-
tal costs for the low flow system are based on the following
equipment:
(1) Reaction system
reaction/holding tank (5-day or less retention time)
agitator
transfer pump
(2) Polymer feed system (batch)
chemical mix tank (5-day retention time)
agitator
chemical metering pump
The polymer feed system is included for the low flow system for
manufacturing processes operating in excess of 16 hours per day.
The addition of polymer for plants operating 16 hours or less per
376
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day is assumed to be unnecessary due to the additional settling
time available.
Only one tank is required for both equalization and treatment
since sedimentation is assumed to be accomplished during non-
production hours (since the holding time is greater than the time
required for treatment). Costs for a chemical precipitant feed
system are not included since lime or caustic addition at low
application rates can be assumed to be done manually by the
operator. A common pump is used for transfer of both the super-
natant and sludge through an appropriate valving arrangement.
As in the normal batch case, annual costs consist mainly of labor
costs for the low flow system and are based on the following
assumptions:
(1) Reaction system
- Operating labor is assumed to be constant at 1 hr/
batch (for pH control, sampling, filling, etc.).
Additional labor is also required for the manual
addition of lime or caustic, ranging from 15 minutes
to 1.5 hrs/batch depending on the feed requirement
(1 to 500 Ibs/batch).
- Maintenance labor is 52 hrs/yr (1 hr/wk).
Energy costs are based on power requirements
associated with the agitator and pump.
Chemical costs are based on the use of hydrated lime
or liquid caustic (50 percent).
(2) Polymer feed system (batch)
See assumptions for normal batch treatment.
The capital and annual costs for chemical precipitation are
presented in Figure VIII-9, page 423, for all three operating
modes.
Sulfide Precipitation and Gravity Settling
Precipitation using sulfide followed by gravity settling is a
technology similar to lime precipitation. In general, sulfide
precipitation removes more metals from wastewater than lime
precipitation because metal sulfides are less soluble than metal
hydroxides.
Sulfide precipitants can be either soluble sulfides (such as
sodium sulfide, or sodium hydrosulfide) or insoluble sulfides
(such as ferrous sulfide). Soluble sulfides generate less sludge
than insoluble sulfides, are less expensive, and are more
377
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commonly used in industry. As such, the sulfide precipitation
module is based on the use of sodium sulfide.
The sulfide precipitation system generally used for this category
consists of the use of sulfide precipitation as a polishing step
following chemical precipitation (described above). Sodium
sulfide is added to the wastewater. The sodium sulfide reacts
with the remaining dissolved metals to form metal sulfides. The
sodium sulfide concentration is calculated as the theoretical
stoichiometric requirement based on the influent metals concen-
tration. To calculate chemical requirements, the sodium sulfide
dosage is obtained by assuming an excess of 25 percent of the
theoretical sodium sulfide dosage. This 25 percent excess of
sodium sulfide is needed to ensure complete reaction to the metal
sulfides within the time allowed in the reaction tank. As noted
below, the sulfide dosage would actually be controlled in a plant
by a specific-ion electrode. Effluent concentrations are based
on treatment effectiveness values for sulfide precipitation.
The reaction tank is equipped with a specific-ion electrode which
monitors the solution potential during the addition of sodium
sulfide. When all of the metal is reacted, excess sulfide ion
causes a sharp negative potential change, which automatically
stops the sulfide addition at the correct point. This control
equipment helps to eliminate the release of H2S gas from the
reaction tank. A ventilation hood is included in the cost esti-
mate to control any t^S which would be released. As a final
protection, an aeration system is included to remove any excess
sulfide prior to discharge.
As with lime precipitation costs, the costs for sulfide precipi-
tation, and gravity settling are based on one of three operation
modes, depending on the influent flow rate: continuous, normal
batch, and low flow batch. The use of a particular mode for cost
estimation purposes was determined on a least cost (total annual-
ized) basis for a given flow rate. The economic breakpoint
between continuous and normal batch is assumed to be 10,600
liters/hour. Below 2,200 liters/hour, it is assumed that the low
flow batch system is most economical. Although all three modes
of operation were available for cost estimations for the cate-
gory, the flow rates for all plants requiring sulfide precipita-
tion were in the continuous range of operation. Since only the
continuous mode was used, the normal batch and low flow batch
operation modes are not included in the following discussion.
For a continuous operation, the following equipment were included
in the determination of the capital and annual costs:
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(1) Sodium sulfide feed system (continuous)
storage units (sized for 15-day storage)
- mix tank (5-minute retention time)
feed pumps
- hood for ventilation
(2) Polymer feed system
storage hopper
- chemical mix tank with agitator
chemical metering pump
(3) pH adjustment system
- rapid mix tank, fiberglass
- agitator (velocity gradient is 300 ft/sec/ft)
- control system
(4) Sulfide precipitation system
- rapid mix tank, fiberglass
- agitator (velocity gradient is 300 ft/sec/ft)
- hood for ventilation
a specific-ion electrode
(5) Flocculation system
slow mix tank, fiberglass
agitator (velocity gradient is 100 ft/sec/ft)
2.0 mg/1 polymer dosage
(6) Gravity settling system
clarifier, circular, steel (overflow rate is 500
gpd/ft^, underflow is 3 percent solids)
sludge pump (1)
Lime is added to adjust pH as necessary. An aeration system
(tank and spargers) for removing excess hydrogen sulfide is also
included in the costs.
The direct capital costs of the lime, sodium sulfide, and polymer
feed systems were based on the respective chemical feed rates
(dry Ibs/hour), which are dependent on the influent waste stream
characteristics. Direct annual costs for the continuous system
include operating and maintenance labor for the feed systems and
the clarifier, the cost of lime, sodium sulfide, and polymer,
maintenance materials and energy costs required to run the agi-
tators and pumps. The assumptions for each of these are similar
379
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to those used for lime precipitation. Cost curves are presented
in Figure VIII-10, page424 for capital and annual costs of the
continuous system.
Vacuum Filtration
The underflow from the clarifier at 3 percent solids is routed to
a rotary precoat vacuum filter, which dewaters sludge to a cake
of 20 percent dry solids. The dewatered sludge is disposed of by
contract hauling and the filtrate is recycled to the chemical
precipitation step.
The capacity of the vacuum filter, expressed as square feet of
filtration area, is based on a yield of 14.6 kg of dry solids/hr
per square meter of filter area (3 Ibs/hr/ft2), a solids
capture of 95 percent and an excess capacity of 30 percent. It
was assumed that the filter was operated eight hours/operating
day.
Cost data were compiled for vacuum filters ranging from 0.9 to
69.7 m2 (9.4 to 750 ft2) of filter surface area. Based on a
total annualized cost comparison, it was assumed that it was more
economical to directly contract haul clarifier underflow streams
which were less than 50 1/hr (0.23 gpm), rather than dewater by
vacuum filtration before hauling.
The costs for the vacuum filtration system include the following
equipment:
(1) Vacuum filter with precoat but no sludge conditioning
(2) Housing
(3) Influent transfer pump
(4) Slurry holding tank
(5) Sludge pumps
The vacuum filter is sized based on 8 hrs/day operation. The
slurry holding tank and pump are excluded when the treatment
system operates 8 hrs/day or less. It was assumed in this case
that the underflow from the clarifier directly enters the vacuum
filter and that holding time volume for the slurry in addition to
the clarifier holding time was unnecessary. For cases where the
treatment system is operated for more than 8 hrs/day, the under-
flow is stored during vacuum filter non-operating hours. The
filter is sized accordingly to filter the stored slurry in an 8
hour period each day. The holding tank capacity is based on the
difference between the plant and vacuum filter operating hours
plus an excess capacity of 20 percent. Cost curves for direct
capital and annual costs are presented in Figure VIII-11, page 425
for vacuum filtration.
380
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The following assumptions were made for developing capital and
annual costs:
(1) Annual costs associated with the vacuum filter were
developed based on continuous operation (24 hrs/day,
365 dys/yr). These costs were adjusted for a plant's
individual operating schedule by assuming that annual
costs are proportional to the hours the vacuum filter
actually operates. Thus, annual costs were adjusted by
the ratio of actual vacuum filter operating hours per
year (8 hrs/day x no. days/yr) to the number of hours
in continuous operation (8,760 hrs/yr).
(2) Annual vacuum filter costs include operating and
maintenance labor (ranging from 200 to 3,000 hrs/yr as
a function of filter size), maintenance materials
(generally less than five percent of capital cost), and
energy requirements (mainly for the vacuum pumps).
(3) Enclosure costs for vacuum filtration were based on
applying rates of $45/ft2 and $5/ft2/yr for capital
and annual costs, respectively to the estimated floor
area required by the vacuum filter system. The capital
cost rate for enclosure is the standard value as dis-
cussed below in the costs for enclosures discussion.
The annual cost rate accounts for electrical energy
requirements for the filter housing. Floor area for
the enclosure is based on equipment dimensions reported
in vendor literature, ranging from 300 ft2 for the
minimum size filter (9.4 ft2) to 1,400 ft2 for a
vacuum filtration capacity of 1,320 ft2.
HoId ing Tanks/Recycle
A holding tank may be used to recycle water back to a process or
for miscellaneous purposes, e.g., storage for hose washdown for
plant equipment. Holding tanks are usually implemented when the
recycled water need not be cooled. The equipment used to deter-
mine capital costs are a fiberglass tank, pump, and recycle
piping. Annual costs are associated only with the pump. The
capital cost of a fiberglass tank is estimated on the basis of
required tank volume. Required tank volume is calculated on the
basis of influent flow rate, 20 percent excess capacity, and four
hour retention time. The influent flow and the degree of recycle
were derived from the assumptions outlined in Table VIII-9.
Cost curves for direct capital and annual costs are presented in
Figure VIII-12, page 426.
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Multimedia Filtration
Multimedia filtration is used as a wastewater treatment polishing
device to remove suspended solids not removed in previous treat-
ment processes. The filter beds consist of graded layers of
coarse anthracite coal and fine sand. The equipment used to
determine capital and annual costs are as follows:
(1) Gravity flow, vertical steel cylindrical filters with
media (anthracite and sand)
(2) Influent storage tank sized for one backwash volume
(3) Backwash tank sized for one backwash volume
(4) Backwash pump to provide necessary flow and head for
backwash operations
air scour system
(5) Influent transfer pump
piping, valves, and a control system
The hydraulic loading rate is 7,335 Iph/mjJ (180 gph/ft2) and
the backwash loading rate is 29,340 lph/m2 (720 gph/ft2).
The filter is backwashed once per 24 hours for 10 minutes. The
backwash volume is provided from the stored filtrate.
Effluent pollutant concentrations are based on the Agency's com-
bined metals data base for treatability of pollutants by filtra-
tion technology.
Cartridge-type filters are used instead of multimedia filters to
treat small flows (less than 800 liters/hour) since they are more
economical than multimedia filters at these flows (based on a
least total annualized cost comparison). The effluent quality
achieved by these filters was equivalent to the level attained by
multimedia filters. The equipment used to determine capital and
annual costs for membrane filtration are as follows:
(1) influent holding tank sized for eight hours retention
(2) pump
(3) prefilter
—prefilter cartridges
—prefilter housings
(4) membrane filter
—membrane filter cartridges
—housing
The majority of annual cost is attributable to replacement of the
spent prefilter and membrane filter cartridges. The maximum
loading for the prefilter and membrane filter cartridges was
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assumed to be 0.225 kg per 0.254 m units length of cartridge.
The annual energy and maintenance costs associated with the pump
are also included in the total annual costs. Cost curves for
direct capital and annual costs are presented in Figure VIII-13,
page 427 for cartridge and multimedia filtration.
Activated Carbon Adsorption
Activated carbon is used to remove dissolved organic contaminants
from wastewater. As the wastewater is pumped through the carbon
column, organic contaminants diffuse into the carbon particles
through pores and are adsorbed onto the pore walls. As organic
material accumulates, the carbon loses its effectiveness and must
be replaced or regenerated periodically.
Two downflow carbon columns in series are used. The leading col-
umn loses its effectiveness first, since most of the organics are
adsorbed in it. When breakthrough occurs (i.e., when the column
effluent concentration of a specified organic exceeds a specified
maximum), the column is taken off-line and the second column
becomes the leading column. When the carbon in the first column
is regenerated or replaced, it becomes the following column.
This configuration, known as a merry-go-round, results in a more
consistent effluent quality than a single, larger column or a
system where one column is active and one on standby. During
column operation, solids accumulate in the interstices of the
carbon bed. To prevent the column from plugging, the bed must be
periodically backwashed to remove these solids. Also, a method
for replacing spent carbon is required. Either replacement with
virgin carbon and disposal of the spent carbon or regeneration of
the spent carbon via off-site or on-site regeneration may be
used.
The following pieces of equipment were included in the determina-
tion of capital and annual costs:
(1) Carbon adsorption system
adsorption columns (2), downflow, merry-go-round
configuration
—hydraulic loading of 2.5 gpm/ft^
initial carbon charge
pump
(2) Backwash facilities
backwash hold tank - to provide 15 gpm/ft^ per
column for 15 min.
pump
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(3) Influent surge tank (1-hour retention time)
(4) Carbon replacement/regeneration facilities
replacement
off-site regeneration
- on-site regeneration
The direct capital costs for the adsorption system pump, backwash
facilities, and surge tank are direct or indirect functions of
the influent flow rate. Direct capital costs for the adsorption
columns and replacement/regeneration facilities are functions of
the influent flow rate and the rate at which carbon is used, or
the carbon exhaustion rate. The rate (expressed in kg/1 or Ibs/
1,000 gal) used depended upon the data available for the types of
organic contaminants being adsorbed. Carbon adsorption data for
a specific type of wastewater were preferred when available;
otherwise, isotherm data for selected organics were used with
conservative design factors. The specific exhaustion rates
selected are provided in the subcategory supplements.
The direct annual costs for the adsorption columns, backwash
facilities, and surge tank included operation and maintenance
labor for the columns and backwash facilities, maintenance
materials, and energy costs for pumping.
The carbon usage rate (kg carbon exhausted/hr) is a function of
the influent flow rate combined with the carbon exhaustion rate
expressed as a carbon usage rate (Ibs carbon exhausted/hr). One
of three operating regimes is chosen on a least cost (total annu-
alized) basis for a given carbon usage rate. Below a usage rate
of about 1.6 Ibs/hr, replacement of spent carbon with virgin
carbon and disposal of the spent carbon as a hazardous waste was
found to be most economical. Between 1.6 and 53 Ibs/hr, regener-
ation by an off-site regeneration service is most cost effective.
On-site regeneration facilities are more economical above 53
Ibs/hr.
For the carbon replacement option, no additional capital invest-
ment is required. Direct annual costs consist of contract
hauling the spent carbon as a hazardous waste and the purchase
and installation of virgin carbon.
Direct capital costs for the off-site regeneration option include
hoppers for dewatering and storage of spent carbon. Also
included is the cost of acquiring an increased carbon inventory
where the actual required inventory is less than the minimum for
economical off-site regeneration (about 20,000 Ibs). Direct
annual costs include the charge for regeneration, transportation
of the carbon to and from the regeneration facility, and costs
for placing carbon into the column.
384
-------
Direct capital costs for an on-site regeneration facility include
costs for a multiple hearth furnace and associated equipment,
spent carbon storage, exhaust gas scrubbers, a carbon slurry
system, quench tank, housing, and controls and instrumentation.
Direct annual costs include operation and maintenance labor for
the regeneration facility, maintenance materials, and electricity
and natural gas costs for the building, electrical equipment, and
furnace. Also included is the cost of replacing carbon lost in
the regeneration process (10 percent of the spent carbon passing
through the furnace) with virgin carbon.
The total direct capital and annual costs for the activated
carbon adsorption system are presented in Figure VIII-14, page
428.
Chemical Oxidation
Chemical oxidation using ozone is an alternative technology to
activated carbon adsorption in the bauxite refining subcategory
for removing dissolved organics from the red mud impoundment
discharges. Compliance costs for the bauxite subcategory were
based on activated carbon adsorption since it was more cost-
effective than chemical oxidation based on a total annualized
cost comparison. Chemical oxidation with ozone proved to be
uneconomical due to the capital intensive ozone generation
equipment required for the relatively high ozone consumption
rates encountered.
Ozone and hydrogen peroxide are considered as chemical oxidants
because they do not result in the release of secondary pollu-
tants, such as manganese or residual chlorine. Given the high pH
of the red mud impoundment discharge (11.5), ozone was selected
over hydrogen peroxide because the peroxide reaction occurs opti-
mally at a pH of 4 or less, whereas ozone only requires neutrali-
zation to a pH of 7. An ozone dosage level of 50 mg/1 was assumed
for the particular organics and COD loadings found in the red mud
impoundment waste stream. Neutralization of the waste stream to
a pH of 7 with lime prior to contact with ozone was accounted for
in developing costs.
The costs for chemical oxidation with ozone were based on the
following equipment:
(1) Ozone generator
ozone preparation and dissolution equipment
electrical and instrumentation
safety and monitoring equipment
(2) Contact chamber, concrete (90 minute contact time)
385
-------
(3) Neutralization system
— mixing tank
pump
agitator
Annual costs comprise mainly the labor and electricity costs
required to operate the ozone generation equipment and operation
and maintenance cost of the neutralization system.
Contract Hauling
Concentrated sludge and waste oils are removed on a contract
basis for off-site disposal. The cost of contract hauling
depends on the classification of the waste as being either
hazardous or nonhazardous. For nonhazardous wastes, a rate of
$0.106/liter ($0.40/gallon) was used in determining contract
hauling costs. The cost for contract hauling hazardous wastes
was developed from a survey of waste disposal services and varies
with the amount of waste hauled. No capital costs are associated
with contract hauling. Annual cost curves for contract hauling
nonhazardous and hazardous wastes are presented in Figure
VIII-15, page 429 .
Enclosures
The costs of enclosures for equipment considered to require
protection from inclement weather were accounted for separately
from the module costs (except for vacuum filtration). In
particular, chemical feed systems were generally assumed to
require enclosure.
Costs for enclosures were obtained by first estimating the
required enclosure area and then multiplying this value by the
$/ft2 unit cost. A capital cost of $45/ft2 was estimated,
based on the following:
structure (including roofing, materials, insulation,
etc.)
site work (masonry, installation, etc.)
electrical and plumbing
The rate for annual costs of enclosures is $5/ft2/yr which
accounts for energy requirements for heating and lighting the
enclosure.
The required enclosure area is determined as the amount of total
required enclosure area which exceeds the enclosure area esti-
mated to be available at a particular plant. It was assumed that
a common structure could be used to enclose all equipment needing
housing unless information was available to indicate that sepa-
rate enclosures are needed (e.g., due to plant layout). The
386
-------
individual areas are estimated from equipment dimensions reported
by vendors and appropriate excess factors. The available enclo-
sure areas were assumed as a function of plant site, based on
experience from site visits at numerous plants.
Segregation
Costs for segregation of wastewaters not included in this regula-
tion (e.g., noncontact cooling water) or for routing regulated
waste streams not currently treated to the treatment system were
included in the compliance cost estimates. The capital costs for
segregating the above streams were determined using a rate of
$6,900 for each stream requiring segregation. This rate is based
on the purchase and installation of 50 feet of 4-inch piping
(with valves, pipe racks, and elbows) for each stream. Annual
costs associated with segregation are assumed to be negligible.
Where a common stormwater-process wastewater piping system was
used at a plant, costs were included for both segregation of each
process waste stream to treatment (based on the above rate) and
segregation of stormwater for rerouting around the treatment
system.
Stormwater segregation cost is $8,800 based on the underground
installation of 300 feet of 24-inch diameter concrete pipe.
COMPLIANCE COST ESTIMATION
To calculate the compliance cost estimates, the model was run
using input data as described previously. A cost summary is
prepared for each plant. An example of this summary may be found
in Table VIII-10, page 411 . Referring to this table, four types
of data are included for each option: run number, total capital
costs, required capital costs, and annual costs. Run number
refers to which computer run the costs were derived from.
Total capital costs include the capital cost estimate for each
piece of wastewater treatment equipment necessary to meet mass
limitations. Required capital costs are determined by consider-
ing the equipment and wastewater treatment system a plant cur-
rently has in place. As discussed previously, the required
capital costs reflect the estimates of the actual capital cost
the facility will incur to purchase and install the necessary
treatment equipment by accounting for what that facility already
has installed. Annual costs are based on all equipment in the
treatment system, as discussed previously.
NONWATER QUALITY ASPECTS
The elimination or reduction of one form of pollution may aggra-
vate other environmental problems. Therefore, Sections 304(b)
387
-------
and 306 of the Act require EPA to consider the nonwater quality
environmental impacts (including energy requirements) of certain
regulations. In compliance with these provisions, EPA has con-
sidered the effect of this regulation on air pollution, solid
waste generation, water scarcity, and energy consumption. This
regulation was circulated to and reviewed by EPA personnel
responsible for nonwater quality environmental programs. While
it is difficult to balance pollution problems against each other
and against energy utilization, the Administrator has determined
that the impacts identified below are justified by the benefits
associated with compliance with the limitations and standards.
The following are the nonwater quality environmental impacts
associated with compliance with BPT, BAT, NSPS, PSES, and PSNS.
Air Pollution, Radiation, and Noise
In general, none of the wastewater treatment or control processes
causes air pollution. Steam stripping of ammonia has a potential
to generate atmospheric emissions; however, with proper design
and operation, air pollution impacts are prevented. Air strip-
ping of ammonia also has a potential to generate atmospheric
emissions, because air stripping transfers ammonia from a water
to an air medium. Because air stripping was only considered as a
technology option for plants with very low wastewater flow, the
Agency does not believe it will create an air quality problem.
Sulfide precipitation operations can evolve hydrogen sulfide
vapors if not properly controlled. EPA's design for sulfide
precipitation includes an automatic pH-controller equipped with a
specific-ion electrode that monitors solution potential during
sulfide addition. When all of the available metal ions are
sequestered by the sulfide, the excess sulfide ion causes a sharp
negative potential change, automatically stopping the sulfide
addition. None of the other wastewater treatment processes
causes objectionable noise and none of the treatment processes
has any potential for radiation hazards.
Solid Waste Disposal
As shown in the subcategory supplements, the waste streams being
discharged contain large quantities of toxic and other metals;
the most common method of removing the metals is by chemical pre-
cipitation. Consequently, significant volumes of heavy metal-
laden sludge are generated that must be disposed of properly.
The technologies that directly generate sludge are:
1. Cyanide precipitation
2. Chemical precipitation (lime, caustic, sulfide, etc.)
3. Multimedia filtration
4. Oil water separation
388
-------
Spent carbon from activated carbon adsorption in the rare earth
metals subcategory also represents a solid waste stream requiring
disposal. The sludge volumes generated by plants in each subcat-
egory are presented in Table VIII-11, page 412, classified by
discharge status.
The estimated sludge volumes generated from wastewater treatment
were obtained from material balances performed by the computer
model during cost estimation. Generally, the solid waste requir-
ing disposal is a dewatered sludge resulting from vacuum filtra-
tion, which contains 20 percent solids (by weight). The solids
content will be lower in cases where it is more economical to
contract haul a waste stream directly from the process without
undergoing treatment.
A major concern in the disposal of sludges is the contamination
of soils, plants, and animals by the heavy metals contained in
the sludge. The leaching of heavy metals from sludge and subse-
quent movement through soils is enhanced by acidic conditions.
Sludges formed by chemical precipitation possess high pH values
and thus are more resistant to acid leaching. Since the largest
amount of sludge that results from the alternatives is generated
by chemical precipitation, it is not expected that metals will be
readily leached from the sludge. Disposal of sludges in a lined
sanitary landfill will further reduce the possibility of heavy
metals contamination of soil, plants, and animals.
Other methods of treating and disposing sludge are available.
One method currently being used at a number of plants is reuse or
recycle, usually to recover metals. Since the metal concentra-
tions in some sludges may be substantial, it may be cost effec-
tive for some plants to recover the metal fraction of their
sludges prior to disposal.
The Solid Waste Disposal Act Amendments of 1980 prohibited EPA
from regulating certain wastes under Subtitle C of RCRA until
after completion of certain studies and certain rulemaking.
Among these wastes are "solid waste from the extraction, bene-
ficiation and processing of ores and minerals." EPA has there-
fore exempted from hazardous waste status any solid wastes from
primary smelting and refining, as well as from exploration, min-
ing, and milling.
The Agency has not made a determination of the hazardous charac-
ter of sludges and solid wastes generated from the secondary
metals processing plants covered by this proposal. Each sludge
generator in the secondary metals subcategories is subject to the
RCRA tests for ignitability, corrosivity, reactivity, and toxic-
ity. Costs for treatment and disposal of such sludges and solid
wastes, as well as nonhazardous sludges and solid wastes, have
been presented in this section.
389
-------
Energy Requirements
The incremental energy requirements of a wastewater treatment
system have been determined in order to consider the impact of
this regulation on natural resource depletion and on various
national economic factors associated with energy consumption.
The calculation of energy requirements for wastewater treatment
facilities proceeded in two steps. First, the portion of operat-
ing costs which were attributable to energy requirements was
estimated for each wastewater treatment module. Then, these
fractions, or energy factors, were applied to each module in all
plants to obtain the energy costs associated with wastewater
treatment for each plant. These costs were summed for each
subcategory and converted to kW-hrs using the electricity charge
rate previously mentioned ($0.0483/kW-hr for March 1982). The
total plant energy usage was calculated based on the data collec-
tion portfolios.
Table VIII-12, page 413 , presents these energy requirements for
each regulatory option in each subcategory. From the data in
this table, the Agency has concluded that the energy requirements
of the proposed treatment options will not significantly affect
the natural resource base nor energy distribution or consumption
in communities where plants are located.
Consumptive Water Loss
Where evaporative cooling mechanisms are used, water loss may
result and contribute to water scarcity problems, a concern pri-
marily in arid and semi-arid regions. This regulation does not
require substantial evaporative cooling and recycling which would
cause a significant consumptive water loss.
390
-------
Table VIII-1
BPT COSTS OF COMPLIANCE FOR THE
NONFERROUS METALS MANUFACTURING CATEGORY
Subcategory
Primary Antimony
Primary Beryllium
Primary and Secondary
Germanium and Gallium
Primary Molybdenum and Rhenium
Metallurgical Acid Plants
(associated with molybdenum
roasters)
Secondary Molybdenum and
Vanadium
Primary Nickel and Cobalt
Primary Precious Metals and
Mercury
Secondary Precious Metals
Primary Rare Earth Metals
Secondary Tantalum
Primary and Secondary Tin
Primary and Secondary Titanium
Secondary Tungsten and Cobalt
Secondary Uranium
Primary Zirconium and Hafnium
Number
of Direct
Dischargers
1
1
0
2
2
3
1
3
3
4
4
1
1
Proposed
Regulation Cost
Estimates ($1982)*
CapitalAnnual
34,200 17,300
A A
B B
B
B
B
B
A
B
B
B
B
1 B
1 27,500
B
9,000
B
A
B
481,000 330,000
B B
28,600 73,644
B B
NOTES: A = no incremental costs
B = based on confidential data
*Costs are shown for the selected option only.
391
-------
Table VIII-2
BAT COSTS OF COMPLIANCE FOR THE
NONFERROUS METALS MANUFACTURING CATEGORY
Number
of Direct
Subcategory
Proposed
Regulation Cost
Estimates ($1982)*
Primary Antimony
Bauxite Refining
Primary Beryllium
Primary and Secondary
Germanium and Gallium
Primary Molybdenum and Rhenium
Metallurgical Acid Plants
(associated with molybdenum
roasters)
Secondary Molybdenum and
Vanadium
Primary Nickel and Cobalt
Primary Precious Metals
and Mercury
Secondary Precious Metals
Primary Rare Earth Metals
Secondary Tantalum
Primary and Secondary Tin
Primary and Secondary Titanium
Secondary Tungsten and Cobalt
Secondary Uranium
Primary Zirconium ana Hafnium
NOTES: B = based on confidential data
*Costs are shown for the selected option only.
**Includes one zero discharger.
Dischargers
1
4**
1
0
2
2
1
1
1
3
1
3
3
4
4
1
1
Capital
41,250
7,600,000
B
B
B
B
B
B
30,000
B
B
B
B
1,030,000
B
54,312
B
Annual
21, 183
2, 980,000
B
B
B
B
B
B
10,000
B
B
B
B
585,000
B
86,452
B
392
-------
Table VIII-3
PSES COSTS OF COMPLIANCE FOR THE
NONFERROUS METALS MANUFACTURING CATEGORY
Proposed
Number Regulation Cost
of Indirect Estimates ($1982)*
Subcategory Dischargers Capital Annual
Primary and Secondary 1 B B
Germanium and Gallium
Secondary Indium 1 B B
Secondary Nickel 1 287,000 120,000
Secondary Precious Metals 29 1,419,000 984,000
Primary Rare Earth Metals 1 B B
Primary and Secondary Tin 2 341,700 119,900
Primary and Secondary Titanium 2 B B
Primary Zirconium and Hafnium 1 B B
NOTES: B = based on confidential information
*Costs are shown for the selected option only,
393
-------
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Table VIII-7
WASTEWATER SAMPLING FREQUENCY
Wastewater Discharge
(liters per day) Sampling Frequency
0 - 37,850 Once per month
37,851 - 189,250 Twice per month
189,251 - 378,500 Once per week
378,501 - 946,250 Twice per week
946,250+ Three times per week
407
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Table VIII-8
COST PROGRAM POLLUTANT PARAMETERS
Parameter
Flow rate
pH
Temperature
Total suspended solids
Acidity (as CaC03>
Aluminum
Ammonia
Antimony
Arsenic
Cadmium
Chromium (trivalent)
Chromium (hexavalent)
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Copper
Cyanide (free)
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Germanium
Iron
Lead
Manganese
Molybdenum
Nickel
Oil and grease
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Units
liters/hour
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mg/1
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mg/1
mg/1
mg/1
mg/1
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mg/1
mg/1
mg/1
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Table VIII-11
NONFERROUS METALS PHASE II
SOLID WASTE GENERATION (tons/yr)
Direct Indirect
Subcategory Dischargers Dischargers
Primary Antimony 33 0
Bauxite Refining 0 0
Primary Beryllium 220 0
Primary Boron 0 0
Primary Cesium and Rubidium 0 0
Primary and Secondary Germanium 0 108
and Gallium
Secondary Indium 0 170
Secondary Mercury 0 0
Primary Molybdenum and Rhenium 1 ,052 0
Secondary Molybdenum and Vanadium 0 0
Primary Nickel and Cobalt 10.4 0
Secondary Nickel 0 281
Primary Precious Metals and Mercury 11.4 0
Secondary Precious Metals 306 1 ,450
Primary Rare Earth Metals 0 7.6
Secondary Tantalum 386 0
Primary and Secondary Tin 447 19.3
Primary and Secondary Titanium 339 50.2
Secondary Tungsten and Cobalt 1,919 0
Secondary Uranium 262 0
Primary Zirconium and Hafnium 3,502 5.6
412
-------
Table VIII-12
NONFERROUS METALS PHASE II
ENERGY CONSUMPTION (kW-hr/yr)
Subcategory
Primary Antimony
Bauxite Refining
Primary Beryllium
Primary Boron
Primary Cesium and Rubidium
Primary and Secondary
Germanium and Gallium
Secondary Indium
Secondary Mercury
Primary Molybdenum and
Rhenium
Secondary Molybdenum and
Vanadium
Primary Nickel and Cobalt
Secondary Nickel
Primary Precious Metals
and Mercury
Secondary Precious Metals
Primary Rare Earth Metals
Secondary Tantalum
Primary and Secondary Tin
Primary and Secondary
Titanium
BPT
11 ,900
0
800
0
0
0
NA
0
580,000
1 ,950,000
20,600
NA
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479,000
44,700
37,000
474,000
680,340
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11 ,500,000
70,500
0
0
0
NA
0
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1 ,960,000
28,570
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487,000
40,600
39,000
479,000
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NA
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0
0
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5,900
0
NA
NA
NA
63,300
NA
4,703,000
25,500
NA
319,200
340,300
413
-------
Table VIII-12 (Continued)
NONFERROUS METALS PHASE II
ENERGY CONSUMPTION (kW-hr/yr)
Subcategory
Secondary Tungsten and
Cobalt
Secondary Uranium
Primary Zirconium and
Hafnium
BPT
BAT
PSES
1,298,000 1,333,000
76,000 85,000
5,353,000 5,407,000
NA
NA
5,300
NOTE:
NA = Not Applicable (to discharge status of plants in this
subcategory)
414
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SECTION IX
EFFLUENT QUALITY ATTAINABLE THROUGH APPLICATION OF THE
BEST PRACTICABLE CONTROL TECHNOLOGY CURRENTLY AVAILABLE
This section sets forth the effluent limitations attainable
through the application of best practicable control technology
currently available (BPT). It also serves to summarize changes
from previous rulemakings in the nonferrous metals manufacturing
category, and presents the development and use of the mass-based
effluent limitations.
A number of considerations guide the BPT analysis. First, efflu-
ent limitations based on BPT generally reflect performance levels
achieved at plants in each subcategory equipped with the best
wastewater treatment facilities. The BPT analysis emphasizes
treatment facilities at the end of a manufacturing process but
can also include in-plant control techniques when they are con-
sidered to be normal practice within the subcategory. Finally,
the Agency closely examines the effectiveness of the various
treatment technologies by weighing the pollutant removals achiev-
able by each treatment alternative and assesses the installation
and operational costs to enable it to determine the economic
achievability of each option.
The limitations are organized by subcategory, i.e., limitations
are presented by subcategory in Section II. The limitations were
developed based on the sampling, treatability, and cost data that
have been presented in this document.
TECHNICAL APPROACH TO BPT
In the past, the technical approach for the nonferrous metals
manufacturing category considered each plant as a single waste-
water source, without specific regard to the different unit pro-
cesses that are used in plants within the same subcategory. This
approach is appropriate for BPT which is generally based upon
end-of-pipe technology. In-process controls are generally not
used to establish BPT; however, they may be used as the basis of
BPT when they are widely demonstrated in the category. In
reevaluating the existing BAT regulations and developing new BAT
regulations, the Agency closely examined each process and the
potential for implementing in-process controls. It became appar-
ent that it was best to establish effluent limitations and stan-
dards recognizing specific waste streams associated with specific
manufacturing operations. This also results in more effective
pollution abatement by tailoring the regulation to reflect these
various wastewater sources. Currently promulgated BPT effluent
limitations using this approach will not be modified unless there
431
-------
are sufficient data supplied to the Agency demonstrating the need
for change.
This approach, referred to as the building block approach,
establishes pollutant discharge limitations for each source of
wastewater identified within the subcategory. Each wastewater
source is allocated a discharge based on the average reported
discharge rates for that source. These flows are normalized
(related to a common basis) using a characteristic production
rate associated with the wastewater source (volume of wastewater
discharged per unit mass of production). The mass limitations
established for a wastewater source are obtained by multiplying
the effluent concentrations attainable by the selected BPT tech-
nology by the regulatory flow for each wastewater source. Thus,
the specific pollutant discharge allowances for a plant's final
discharge permit are calculated by multiplying the appropriate
production rates with the corresponding mass limitations for each
wastewater source in that plant, and then summing the results.
This calculation is performed to obtain the one-day maximum and
the monthly average limitations. It is important to note that
the plant need only comply with the mass limitations and not the
flow allowances or concentrations. In cases where process and
nonprocess wastewater sources not specifically regulated by this
proposal exist within the facility, the permit authority must
treat these on a case-by-case basis.
Although each waste stream may not include each selected pollu-
tant, a discharge allowance is provided for all pollutants in
every waste stream because each waste stream contributes to the
total loading of a combined waste treatment system. Since a dis-
charge allowance is included for each pollutant in every waste
stream, facilities would not be required to reduce pollutant
concentrations below the performance limits of the technology.
Instead, this approach allows plants to achieve the performance
determined for the technology at the plant discharge point.
Therefore, the mass limitation for each pollutant in each build-
ing block is the product of the concentration achievable by the
technology basis of the limitation and the regulatory flow for
that building block.
In determining the technology basis for BPT, the Agency reviewed
a wide range of technology options and selected six alternatives
which could be applied to nonferrous metals manufacturing as BPT
options. These options include:
1. Option A - End-of-pipe treatment consisting of chemical
precipitation and clarification, and preliminary treat-
ment, where necessary, consisting of oil skimming,
cyanide precipitation, and ammonia steam stripping.
This combination of technology reduces toxic metals and
cyanide, conventional, and nonconventional pollutants.
432
-------
2. Option B - Option B is equal to Option A preceded by
flow reduction of process wastewater through the use
of cooling towers for contact cooling water and holding
tanks for all other process wastewater subject to
recycle.
3. Option C - Option C is equal to Option B plus end-of-
pipe polishing filtration for further reduction of
toxic metals and TSS.
4. Option D - Option D is equal to Option C plus treatment
of isolated waste streams with activated carbon adsorp-
tion for removal of toxic organics and activated
alumina for reduction of fluorides and arsenic concen-
trations. This option was only considered for non-
ferrous phase I.
5. Option E - Option E consists of Option C plus activated
carbon adsorption applied to the total plant discharge
as a polishing step to reduce toxic organic concentra-
tions.
6. Option F - Option F consists of Option C plus reverse
osmosis treatment to attain complete recycle of all
process wastewater. This option was only considered
for nonferrous phase I.
A combination of these options was examined for each subcategory
based on the concentration of pollutants found in raw wastewaters
of each subcategory. For example, toxic organic pollutants were
not found above treatable concentrations in the primary nickel
and cobalt subcategory. Therefore, treatment Option E, which
contains activated carbon adsorption, was not considered. For
each of the selected options, the mass of pollutant removed and
the costs associated with application of the option were esti-
mated. A description regarding the pollutant removal estimates
associated with the application of each option is presented in
Section X, while the cost methodology is presented in Section
VIII.
MODIFICATIONS TO EXISTING BPT EFFLUENT LIMITATIONS
Prior to this rulemaking session, BPT effuent limitations have
been promulgated for only one of the 21 nonferrous metals manu-
facturing phase II subcategories, namely bauxite refining.
At this time, 20 new subcategories are proposed for inclusion in
the nonferrous metals manufacturing point source category. There
have been no previous effluent limitations developed for these 20
subcategories listed below:
433
-------
1. Primary Antimony
2. Primary Beryllium
3. Primary Boron
4. Primary Cesium and Rubidium
5. Primary and Secondary Germanium and Gallium
6. Secondary Indium
7. Secondary Mercury
8. Primary Molybdenum and Rhenium
9. Secondary Molybdenum and Vanadium
10. Primary Nickel and Cobalt
11. Secondary Nickel
12. Primary Precious Metals and Mercury
13. Secondary Precious Metals
14. Primary Rare Earth Metals
15. Secondary Tantalum
16. Primary and Secondary Tin
17. Primary and Secondary Titanium
18. Secondary Tungsten and Cobalt
1 9. Secondary Uranium
20. Primary Zirconium and Hafnium
It is not EPA's intention to modify effluent limitations promul-
gated in previous rulemakings unless new information warrants
change. As such, EPA is proposing that the metallurgical acid
plants subcategory be modified to include acid plants associated
with primary molybdenum.
EPA proposed to include metallurgical acid plants associated
(i.e., on-site) with primary molybdenum roasters as part of the
metallurgical acid plants subcategory finalized on March 8, 1984
(49 FR 8742). All these plants would accordingly have identical
effluent limitations and standards. In making this determina-
tion, the Agency considered the way in which acid plants are
operated when associated with the primary smelters and the
characteristics of the wastewater generated by each type of acid
plant. Our conclusion is that these processes, rate of process
discharge, and wastewater matrices are similar, justifying a
single subcategory for all acid plants.
Metallurgical acid plants are constructed on-site with primary
copper, lead, zinc, and molybdenum smelters to treat the smelter
emissions, remove the sulfur dioxide, and produce sulfuric acid
as a marketable by-product. Although two basic technologies,
single contact and double contact, are used in the industry, the
Agency found no predominance of either technology in place in
plants of the four metal types. Nor was there any significant
observable difference in the amount of water discharged from
plants using the two technologies. Finally, the Agency found no
difference in the characterization of the wastewater at plants
which burn supplemental sulfur.
434
-------
The processes are also similar in terms of waste streams gener-
ated. Wastewaters are typically combined in acid plants into a
single waste stream (acid plant blowdown). Principal streams
going into the blowdown (compressor condensate, blowdown from
acid plant scrubbing, mist precipitation, mist elimination, and
steam generation) are common to all four types of plants.
The wastewater matrices from all four types of acid plants also
are similar. The Agency reviewed the analytical data that were
obtained in sampling programs described in Section V and compared
the characteristics of untreated acid plant blowdown from plants
associated with each of the four primary metals considered.
There were similar concentrations (i.e., in the same order of
magnitude) of antimony, arsenic, chromium, mercury, and selenium,
among the four. All of these metals were present at concentra-
tions that are treatable to the same effluent concentration upon
application of chemical precipitation and sedimentation or chemi-
cal precipitation, sedimentation and multimedia filtration, and
are within the range used in calculating treatment effectiveness
for these technologies. One dissimilarity which was observed
between molydbenum acid plant wastewater matrices and the
matrices associated with other acid plants is that treatable
concentrations of fluoride are present in molydbenum acid plant
wastewaters and not in the wastewaters from other metallurgical
acid plants. The Agency is giving notice that it is considering
establishing limitations for fluoride in discharges from
metallurgical acid plants associated with primary molybdenum
roasters and solicits comment on this action.
Therefore, in light of these essential similarities of process,
wastewater flow and composition, we have chosen to include all
acid plants in a single subcategory.
BPT OPTION SELECTION
The treatment option selected for the technology basis of BPT
throughout the category is Option A (chemical precipitation and
sedimentation, with ammonia steam stripping, oil skimming and
cyanide precipitation pretreatment where appropriate). Chemical
precipitation, sedimentation, and ammonia steam stripping are
widely demonstrated at plants with the best treatment practices
in the nonferrous metals manufacturing category. Of the 70
discharging plants, 41 plants have treatment to remove metals and
suspended solids, one plant has technology for cyanide precipita-
tion, 10 have technology for cyanide oxidation, four practice
ammonia stripping and two practice end-of-pipe filtration. The
remainder of the dischargers did not report any treatment for
their nonferrous metals manufacturing wastewaters.
435
-------
Recycle after treatment consisting of lime precipitation and
sedimentation is practiced at one plant. Thirty-nine plants
practice recycle of scrubber water without any treatment, and two
plants practice recycle of process water using cooling towers.
To illustrate the frequency of various treatment techniques,
Table IX-1 (page 448) summarizes the current treatment technology
in-place for plants in each subcategory. As can be seen, the
preponderance of technology is chemical precipitation and sedi-
mentation equipment. Multimedia filtration (Option C) as an
add-on polishing step to the precipitation and sedimentation
system was not selected at BPT since it was less widely
demonstrated.
Effluent BPT limitations have been promulgated for only one,
bauxite refining, of the 21 phase II subcategories. Of the
remaining 20 subcategories, EPA has reserved setting BPT limita-
tions for the following five subcategories because there are no
existing direct discharging plants in these subcategories:
1. Primary Boron
2. Primary Cesium and Rubidium
3. Secondary Indium
4. Secondary Mercury
5. Secondary Nickel
Effluent BPT limitations have been proposed for the following 15
subcategories:
1. Primary Antimony
2. Primary Beryllium
3. Primary and Secondary Germanium and Gallium
4. Primary Molybdenum and Rhenium
5. Secondary Molybdenum and Vanadium
6. Primary Nickel and Cobalt
7. Primary Precious Metals and Mercury
8. Secondary Precious Metals
9. Primary Rare Earth Metals
10. Secondary Tantalum
11. Primary and Secondary Tin
12. Primary and Secondary Titanium
13. Secondary Tungsten and Cobalt
14. Secondary Uranium
15. Primary Zirconium and Hafnium
In the discussions that follow, a brief description of the option
selected for each of these 15 subcategories will be presented.
The mass limitations developed for these subcategories are
presented in Section II of this document and the corresponding
supplements. Table IX-2 (page 450 ) presents the pollutants
selected for limitation in each of the subcategories.
436
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PRIMARY ANTIMONY
The technology basis for the BPT limitations is chemical
precipitation and sedimentation technology to remove metals and
solids from combined wastewaters and to control pH. These
technologies are not in-place at the one discharger in this
subcategory; however, this technology is widely demonstrated at
plants in other nonferrous metals manufacturing categories.
Implementation of the proposed BPT limitations will remove annu-
ally an estimated 2,642 kg of toxic metals and 965 kg of TSS from
the raw waste load. We project a capital cost of approximately
$34,200 and an annualized cost of approximately $17,300 for
achieving proposed BPT.
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.
PRIMARY BERYLLIUM
The technology basis for the BPT limitations is chemical precipi-
tation and sedimentation technology to remove metals and solids
from combined wastewaters and to control pH and fluoride. This
technology is already in-place at the one discharger in the
subcategory.
Because the one discharging facility in the primary beryllium
subcategory already has the BPT technology in-place, and our data
indicate that the technology is achieving the proposed BPT limi-
tations, there will be no pollutant removal above the current
discharge level and no incremental capital or annual costs.
More stringent technology options were not selected for BPT since
they require in-process changes or end-of-pipe technologies not
practiced at either of the two plants in the subcategory. These
technologies must, therefore, be transferred from other subcate-
gories where they have been defined as BAT rather than BPT.
PRIMARY AND SECONDARY GERMANIUM AND GALLIUM
We are proposing BPT requirements for the primary and secondary
germanium and gallium subcategory, since BPT has not yet been
promulgated. Level A provisions are applicable to facilities
which only reduce germanium dioxide in a hydrogen furnace and
wash and rinse the germanium product in conjunction with zone
refining. Level B provisions are applicable to all other facili-
ties in the subcategory. The technology basis for both Levels A
437
-------
and B for the BPT limitations is chemical precipitation and
sedimentation technology to remove metals, fluoride, and solids
from combined wastewaters and to control pH. The pollutants
specifically proposed for regulation at BPT are arsenic, lead,
zinc, germanium, fluoride, TSS, and pH.
Although there are no existing direct dischargers in this sub-
category, BPT is proposed for any existing zero discharger that
elects to discharge at some point in the future. This action is
deemed necessary because wastewaters from germanium and gallium
operations which contain significant loadings of toxic pollutants
are currently being disposed of in a RCRA permitted surface
impoundment.
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. EPA is proposing a two tier
regulatory scheme for this subcategory, however, the same tech-
nology applies to both levels of BPT.
The cost and specific removal data for this subcategory are not
presented here because the data on which they are based have been
claimed to be confidential.
PRIMARY MOLYBDENUM AND RHENIUM
The technology basis for the BPT limitations is chemical precipi-
tation and sedimentation technology to remove metals and solids
from combined wastewaters and to control pH, and ammonia steam
stripping preliminary treatment. These technologies are already
in-place at one of the two dischargers in the subcategory.
Implementation of the proposed BPT limitations will remove annu-
ally an estimated 73,630 kg of toxic metals, 1,049 kg of molybde-
num, 63,440 kg of ammonia, and 51,529 kg of TSS from the raw
waste load. While one discharging plant has the equipment
in-place to comply with BPT, we do not believe that the plants
are currently achieving the BPT mass limitations. The cost and
specific removal data for this subcategory are not presented here
because the data on which they are based have been claimed to be
confidential.
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.
438
-------
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
lime 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 dischargers
included under the expanded applicability. The pollutants speci-
fically proposed for regulation at BPT are arsenic, cadmium,
copper, lead, zinc, TSS, and pH. The Agency is also considering
establishing limitations for fluoride in discharges from acid
plants associated with primary molybdenum roasters and solicits
comment on this action.
Implementation of the proposed BPT limitations will remove annu-
ally an estimated 8,026 kg of toxic metals, 543 kg of molybdenum,
and 10,903 kg of TSS from the raw waste load at metallurgical
acid plants associated with molybdenum roasters. While both
plants have the equipment in-place to comply with BPT, we do not
believe that the plants are currently achieving the proposed BPT
limitations. The cost and specific removal data for this sub-
category are not presented here because the data on which they
are based have been claimed to be confidential.
SECONDARY MOLYBDENUM AND VANADIUM
The technology basis for the BPT limitations is chemical precipi-
tation and sedimentation technology to remove metals and solids
from combined wastewaters and to control pH, and steam stripping
to remove ammonia. These technologies are already in-place at
the one discharger in the subcategory.
Implementation of the proposed BPT limitations will remove annu-
ally an estimated 25,100 kg of toxic metals, and 74,000 kg of TSS
from the raw waste laod. Although the one discharging facility
in this subcategory has the technology in place to comply with
BPT, we do not believe that the plant is currently achieving the
proposed BPT mass limitations. The cost and specific removal
data for this subcategory are not presented here because the data
on which they are based have been claimed to be confidential.
More stringent technology options were not selected for BPT since
they require in-process changes or end-of-pipe technologies not
practiced at the one plant in the subcategory. These technolo-
gies must, therefore, be transferred from other subcategories
where the technologies have been defined as BAT rather than BPT.
439
-------
PRIMARY NICKEL AND COBALT
The technology basis for the BPT limitations is chemical precipi-
tation and sedimentation technology to remove metals and solids
from combined wastewaters and to control pH, and ammonia steam
stripping to remove ammonia. Chemical precipitation and sedimen-
tation technology is already in-place at the one discharger in
the subcategory.
Implementation of the proposed BPT limitations will remove annu-
ally an estimated 241 kg of toxic metals and 27 kg of cobalt from
the raw waste load. While the one discharging plant has the
equipment in-place to comply with BPT, we do not believe that the
plant is currently achieving the proposed BPT mass limitations.
The cost and specific removal data for this subcategory are not
presented here because the data on which they are based have been
claimed to be confidential.
More stringent technology options were not selected for BPT since
they require in-process changes or end-of-pipe technologies not
practiced at the one plant in the subcategory. These technolo-
gies must, therefore, be transferred from other subcategories
where the technologies have been defined as BAT rather than BPT.
PRIMARY PRECIOUS METALS AND MERCURY
The technology basis for the BPT limitations is chemical precipi-
tation and sedimentation technology to remove metals and solids
from combined wastewaters and to control pH, and oil skimming to
remove oil and grease. These technologies are not in-place at
the one discharger in this subcategory, but are widely demon-
strated at plants in other nonferrous metals manufacturing
subcategories.
Implementation of the proposed BPT limitations will remove annu-
ally an estimated 914 kg of toxic metals and 334 kg of TSS from
the raw waste load. We project a capital cost of $27,500 and an
annualized cost of $9,000 for achieving proposed BPT limitations.
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.
SECONDARY PRECIOUS METALS
The technology basis for the BPT limitations is chemical precipi-
tation and sedimentation technology to remove metals and solids
from combined wastewaters and to control pH, ammonia steam strip-
ping pretreatment to remove ammonia, and cyanide precipitation
440
-------
pretreatment to remove free and complexed cyanide. Chemical
precipitation and sedimentation technology is already in-place at
20 of the dischargers in the subcategory. One plant has cyanide
precipitation in-place. Although ammonia steam stripping is not
currently practiced by any of the plants in this subcategory, air
stripping is practiced at one plant and steam stripping is
demonstrated at plants in other nonferrous metals manufacturing
subcategories.
Implementation of the proposed BPT limitations will remove annu-
ally an estimated 34,570 kg of toxic pollutants (which include
6.3 kg of cyanide), 490 kg of ammonia, and 11,200 kg of TSS from
the raw waste load. The cost and specific removal data for this
subcategory are not presented here because the data on which they
are based have been claimed to be confidential.
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.
PRIMARY RARE EARTH METALS
The technology basis for the BPT limitations is chemical precipi-
tation and sedimentation technology to remove metals and solids
from combined wastewaters and to control pH. These technologies
are already in-place at the one direct discharger in the
subcategory.
Implementation of the proposed BPT limitations will remove annu-
ally an estimated 0.13 kg of toxic metals and 81.6 kg of TSS over
estimated raw waste load (no toxic organics would be removed).
We project no incremental capital or annual cost for achieving
proposed BPT because the technology is already in-place at the
one direct discharging facility in this subcategory.
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. Therefore, they are more
appropriately considered under BAT.
SECONDARY TANTALUM
The technology basis for the BPT limitations is chemical precipi-
tation and sedimentation technology to remove metals and solids
from combined wastewaters and to control pH. These technologies
are already in-place at three dischargers in the subcategory.
Implementation of the proposed BPT limitations will remove annu-
ally an estimated 26,268 kg of toxic metals and 20,079 kg of TSS
441
-------
from the raw waste load. The cost and specific removal data for
this subcategory are not presented here because the data on which
they are based have been claimed to be confidential.
More stringent technology options were not selected for BPT since
they require in-process changes or end-of-pipe technologies not
practiced by any of the three existing plants in the subcategory.
These technologies must, therefore, be transferred from other
subcategories where the technologies have been defined as BAT
rather than BPT.
PRIMARY AND SECONDARY TIN
The technology basis for the BPT limitations is chemical precipi-
tation and sedimentation technology to remove metals, fluoride,
and solids from combined wastewaters and to control pH, with pre-
liminary treatment consisting of cyanide precipitation and
ammonia steam stripping. Chemical precipitation and sedimenta-
tion technology is already in-place at two dischargers in the
subcategory.
Implementation of the proposed BPT limitations will annually
remove from raw wastewater an estimated 1,169 kg of toxic metals,
144 kg of cyanide, 237,220 kg of fluoride, and 58,600 kg of TSS.
The cost and specific removal data for this subcategory are not
presented here because the data on which they are based have been
claimed to be confidential.
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.
PRIMARY AND SECONDARY TITANIUM
We are proposing BPT requirements for the primary and secondary
titanium subcategory, since BPT has not yet been promulgated.
The technology basis for the BPT limitations is chemical precipi-
tation and sedimentation technology to remove metals and solids
from combined wastewaters and to control pH, and oil skimming
preliminary treatment for streams with treatable concentrations
of oil and grease. These technologies are already in-place at
two of the four direct dischargers in the subcategory. EPA is
proposing a two tier regulatory scheme for this subcategory;
however, the same technologies apply to both tiers at BPT. The
pollutants specifically proposed for regulation at BPT are
chromium, lead, nickel, thallium, fluoride, titanium, oil and
grease, TSS, and pH.
442
-------
Implementation of the proposed BPT limitations will remove annu-
ally an estimated 87 kg of toxic metals, 5,791 kg of titanium,
and 64,446 kg of TSS from the raw waste load. While two plants
have the equipment in-place to comply with BPT, we do not believe
that the plants are currently achieving the proposed BPT limita-
tions. We project a capital cost of $989,000 and annualized cost
of $588,000 for achieving the proposed BPT limitations in all
plants.
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.
SECONDARY TUNGSTEN AND COBALT
The technology basis for the BPT limitations is chemical precipi-
tation and sedimentation technology to remove metals and solids
from combined wastewaters and to control pH, ammonia steam strip-
ping to remove ammonia and oil skimming to remove oil and grease.
Chemical precipitation and sedimentation technology is already
in-place at three direct dischargers in the subcategory.
Implementation of the proposed BPT limitations will remove annu-
ally an estimated 150,700 kg of toxic metals, 123,575 kg of
ammonia, and 108,700 kg of TSS from the raw waste load. The cost
and specific removal data for this subcategory are not presented
here because the data on which they are based have been claimed
to be confidential.
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.
SECONDARY URANIUM
The technology basis for the BPT limitations is chemical precipi-
tation and sedimentation technology to remove metals and solids
from combined wastewaters and to control pH, along with ammonia
steam stripping preliminary treatment to control ammonia.
Chemical precipitation and sedimenation technology is already
in-place at the one discharger in the subcategory.
Implementation of the proposed BPT limitations will remove annu-
ally an estimated 1,280 kg of toxic metals and 1,763 kg of TSS
from the estimated raw waste load. While the one discharging
plant has the equipment in-place to comply with BPT, we do not
believe that the plant is currently achieving the proposed BPT
limitations. We project capital and annual costs of $28,600 and
443
-------
$73,644 (1982 dollars) respectively for modifications to tech-
nology presently in-place at the discharging facility to achieve
proposed BPT regulations.
More stringent technology options were not selected for BPT since
they require in-process changes or end-of-pipe technologies not
practiced by any of the plants in the subcategory. These tech-
nologies must, therefore, be transferred from other subcategories
where the technologies have been defined as BAT rather than BPT.
PRIMARY ZIRCONIUM AND HAFNIUM
We are proposing BPT requirements for the primary zirconium and
hafnium subcategory, since BPT has not yet been promulgated. The
technology basis for the BPT limitations is chemical precipita-
tion and sedimentation technology to remove metals and solids
from combined wastewaters and to control pH, plus barium chloride
coprecipitation to control radium, and ammonia steam stripping
and cyanide precipitation preliminary treatment of streams
containing ammonia and cyanide. Chemical precipitation and
sedimentation technology and ammonia steam stripping is already
in-place at one discharger in the subcategory. The pollutants
specifically proposed for regulation at BPT are chromium,
cyanide, lead, nickel, ammonia, radium (226), TSS, and pH.
Implementation of the proposed BPT limitations will remove annu-
ally an estimated 637 kg of toxic metals, 2,188 kg of cyanide and
293,862 kg of TSS from the raw waste load. The cost and specific
removal data for this subcategory are not presented here because
the data on which they are based have been claimed to be
confidential.
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.
EXAMPLES OF BUILDING BLOCK APPROACH IN DEVELOPING PERMITS
A plant is to receive a discharge allowance for a particular
building block only if it is actually operating that particular
process. In this way, the building block approach recognizes and
accommodates the fact that not all plants use identical steps in
manufacturing a given metal. The plant need not be discharging
wastewater from the process to receive the allowance, however.
Thus, if the regulation contains a discharge allowance for wet
scrubber effluent and a particular plant has dry scrubbers, it
cannot include a discharge allowance for wet scrubbers as part of
its aggregate limitation. On the other hand, if it has wet
scrubbers and discharges less than the allowable limit or does
444
-------
not discharge from the scrubbers, it would receive the full regu-
latory allowance in developing the permit.
There are several facilities within this category that have inte-
f rated manufacturing operations; that is, they combine wastewater
rom smelting and refining operations, which are part of this
point source category, with wastewater from other manufacturing
operations which are not a part of this category, and treat the
combined stream prior to discharge.
The building block approach is only to be used when the individ-
ual discharger combines wastewater from various processes and
co-treats the wastewater before discharge through a single dis-
charge pipe. The building block approach allows the determina-
tion of appropriate effluent limitations for the discharge point
by combining appropriate limitations based upon the various pro-
cesses that contribute wastewater to the discharge point.
As an example, we will use a facility which combines secondary
precious metals, secondary silver refining, and precious metals
forming wastewater and treats this water in a waste treatment
system prior to discharge. The permit writer must first identify
the manufacturing operations using process water in the facility.
The facility in this example discharges wastewater from gold
precipitation and filtration, precipitation and filtration of
nonphotographic solutions (silver), and surface treatment rinse
water. Then by multiplying the production calculated according
to 40 CFR 122.63(b)(2) for each of these operations by the
limitations or standards in 40 CFR 421 for both precipitation and
filtration waste streams and in 40 CFR 471 for surface treat-
ment rinse water and by summing the product obtained for each of
these waste streams, the permit writer can obtain the allowable
mass discharge.
If, for example, the production of gold resulting from gold pre-
cipitation and filtration is 200,000 troy ounces per year, the
production of silver resulting from precipitation and filtration
of nonphotographic solutions is 150,000 troy ounces per year, and
the surface treatment rinse water production is 7.774 off-kkg of
precious metals surface treated per year, the maximum for any one
day limitation based on the best available technology economi-
cally achievable (BAT) for the pollutant copper is 1.7439 kg/yr
as calculated below:
Gold precipitation and filtration
200,000 TO/yr x 5.632 mg/TO = 1.1264 kg/yr
445
-------
Precipitation and filtration of nonphotographlc solutions
150,000 TO/yr x 3.930 mg/TO - 0.5895 kg/yr
Surface treatment rinse water
7.774 off-kkg/yr x 3,600 mg/kkg = 0.028 kg/yr
Total - 1.7439 kg/yr
In establishing limitations for integrated facilities for which a
portion of the plant is covered by concentration-based limita-
tions, the permit writer can determine the appropriate mass limi-
tations for the entire facility or point source as follows. The
portion of the wastewater covered by this category receives mass
limitations according to the building block methodology described
above. The permit writer must then determine an appropriate flow
for the portion of the facility subject to concentration-based
limitations and multiply it by the concentration limitations to
yield mass limitations. The mass limitations applicable to the
discharge are obtained by summing these two sets of mass
limitations.
As an example, we will use a facility which combines process
wastewater from a mill using froth flotation to concentrate
copper ore with SC>2 scrubber water from a primary molybdenum
roaster. The portion of the limitations attributable to the
roaster S(>2 scrubber water is calculated by multiplying the
limitations in suppart U of 40 CFR 421 by the molybdenum sulfide
roaster production. The permit writer must then determine the
appropriate flow for the discharge from the mill and multiply it
by the concentrations set forth in subpart J of 40 CFR 440 at 47
FR 54618. If the molybdenum sulfide roaster production is
175,000 kkg per year and the flow from the froth flotation mill
is 2,000,000 liters per year (based on the permitter's judgment),
the maximum for any one day limitation based on the best avail-
able technology economically achievable (BAT) for the pollutant
nickel is 1511.7 kg/yr as calculated below:
Froth flotation mill wastewater
2,000,000 1/yr x 0.2 mg/1 x 1 kg/10 6 mg = 0.4 kg/yr
SO? Scrubber Water
8.636 mg/kg x 175,000 kkg/yr = 1511.3 kg/yr
Total = 1511.7 kg/yr
446
-------
The Agency recognizes that there may be different technology
bases for the limitations and standards applicable to an inte-
grated facility. As an example, the technology basis for BAT for
tin smelting is chemical precipitation, sedimentation and filtra-
tion whereas the technology basis for BAT for tin forming is lime
precipitation and sedimentation. This does not necessarily imply
that the facility install end-of-pipe filtration on all or a part
of the discharge flow. EPA developed these limitations based on
specified in-plant controls and end-of-pipe treatment technology;
however, it does not require that the facility implement these
specific in-plant controls and end-of-pipe technology. The
facility combining wastewater from manufacturing operations
covered by the two categories must install technology and modify
the manufacturing operations so as to comply with the mass
limitations.
447
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Table IX-2
BPT REGULATED POLLUTANT PARAMETERS
Subcategory
Primary Antimony
Primary Beryllium
Primary and Secondary Germanium
and Gallium
Primary Molybdenum and Rhenium
Secondary Molybdenum and Vanadium
Primary Nickel and Cobalt
Pollutant Parameters
114. antimony
115
122.
123.
117.
119
120
115.
122.
128.
1 1 5.
122.
124.
125.
114.
122.
1 24.
120.
124.
arsenc
lead
mercury
TSS
PH
beryllium
chromium (total)
copper
fluoride
TSS
pH
arsenic
lead
zinc
fluoride
germanium
TSS
arsenic
lead
nickel
selenium
molybdenum
ammonia (as N)
TSS
pH
antimony
lead
nickel
molybdenum
ammonia (as N)
TSS
pH
copper
nickel
cobalt
ammonia (as N)
TSS
pH
450
-------
Table IX-2 (Continued)
BPT REGULATED POLLUTANT PARAMETERS
Subcategory
Primary Precious Metals and Mercury
Pollutant Parameters
Secondary Precious Metals
Primary Rare Earth Metals
Secondary Tantalum
Primary and Secondary Tin
115.
122.
123.
126.
128.
120
121 ,
128
119.
122.
124.
arsenic
lead
mercury
silver
zinc
oil and grease
TSS
pH
copper
cyanide
zinc
ammonia (as N)
TSS
PH
chromium
lead
nickel
TSS
pH
(Total)
120.
122.
124.
128.
copper
lead
nickel
zinc
TSS
PH
114. antimony
121. cyanide
122. lead
124. nickel
tin
fluoride
TSS
pH
ammonia (as
N)
451
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Table IX-2 (Continued)
BPT REGULATED POLLUTANT PARAMETERS
Subcategory
Primary and Secondary Titanium
Secondary Tungsten and Cobalt
Secondary Uranium
Primary Zirconium and Hafnium
Pollutant Parameters
119. chromium (total)
122. lead
124. nickel
127. thallium
fluoride
titanium
oil and grease
TSS
pH
120. copper
124. nickel
cobalt
oil and grease
ammonia (as N)
TSS
pH
119. chromium (total)
120. copper
124. nickel
uranium
ammonia (as N)
fluoride
TSS
pH
119. chromium (total)
121. cyanide (total)
122. lead
124. nickel
radium 226
ammonia (as N)
TSS
pH
452
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SECTION X
EFFLUENT QUALITY ATTAINABLE THROUGH APPLICATION OF
THE BEST AVAILABLE TECHNOLOGY ECONOMICALLY ACHIEVABLE
This section sets forth the effluent limitations attainable
through the application of best available technology economically
achievable (BAT). It also serves to summarize changes from
previous rulemakings in the nonferrous metals manufacturing
category, and presents the development and use of the mass-based
effluent limitations.
A number of factors guide the BAT analysis including the age of
equipment and facilities involved, the process employed, process
changes, nonwater quality environmental impacts (including energy
requirements), and the costs of application of such technology.
BAT technology represents the best available technology economi-
cally achievable at plants of various ages, sizes, processes, or
other characteristics. In those categories whose existing per-
formance is uniformly inadequate EPA may transfer technology from
a different subcategory or category. BAT may include process
changes or internal controls, even when these are not common
industry practice. This level of technology also considers those
plant processes and control and treatment technologies which, at
pilot plant and other levels, have demonstrated both technologi-
cal performance and economic viability at a level sufficient to
justify investigation.
The required assessment of BAT "considers" costs, but does not
require a balancing of costs against effluent reduction benefits
(see Weyerhaeuser v.. Costle, 11 ERG 2149 (D.C. Cir. 1978)). In
developing the proposed BAT, however, EPA has given substantial
weight to the economic achievability of the technology. The
Agency has considered the volume and nature of discharges
expected after application of BAT, the general environmental
effects of the pollutants, and the costs and economic impacts of
the required pollution control levels.
The BAT effluent limitations are organized by subcategory for
individual sources of wastewater. The limitations were developed
based on the attainable effluent concentrations and production
normalized flows that have been presented in this document.
Implementation of the proposed BAT effluent limitations is
expected to remove 336,461 kg/yr of toxic pollutants which is
1,133 kg/yr above BPT discharge estimates. The estimated Capital
cost of BAT is $2.8 million (1982 dollars), and the estimated
annual cost is $3.77 million (1982 dollars).
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TECHNICAL APPROACH TO BAT
In the past, the technical approach for the nonferrous metals
manufacturing category considered each plant as a single waste-
water source, without specific regard to the different unit
processes that are used in plants within the same subcategory.
For this rulemaking, end-of-pipe treatment technologies and
in-process controls were examined in the selection of the best
available technology. After examining in-process controls, it
becomes apparent that it was best to establish effluent limita-
tions and standards recognizing specific waste streams associated
with specific manufacturing operations. The approach adopted for
this proposal considers the individual wastewater sources within
a plant, resulting in more effective pollution abatement by
tailoring the regulation to reflect these various wastewater
sources. This approach, known as the building block approach,
was presented in Section IX. Another example of this approach is
given at the end of this section.
INDUSTRY COST AND POLLUTANT REDUCTION BENEFITS OF THE VARIOUS
TREATMENT OPTIONS
Under these guidelines, six treatment options were evaluated in
selection of BAT for the category. Because of the diverse pro-
cesses and raw materials used in the nonferrous category, the
pollutant parameters found in various waste streams are not uni-
form. This required the identification of significant pollutants
in the various waste streams so that appropriate treatment tech-
nologies could be selected for further evaluation. The options
considered applicable to the nonferrous metals manufacturing sub-
categories are presented in Table X-1 (page 472). A thorough
discussion of the treatment technologies considered applicable to
wastewaters from the nonferrous metals manufacturing category is
presented in Section VII of this document. In Section VII, the
attainable effluent concentrations of each technology are pre-
sented along with their uniform applicability to all subcate-
gories. Mass limitations developed from these options may vary,
however, because of the impact of different production normalized
wastewater discharge flows.
In summary, the treatment technologies considered for nonferrous
metals manufacturing are:
Option A is based on:
Chemical precipitation of metals followed by sedimenta-
tion, and, where required, cyanide precipitation,
ammonia steam stripping, and oil skimming pretreatment.
(This option is equivalent to the technology on which
BPT is based.)
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Option B is based on:
Option A (chemical precipitation and sedimentation)
plus process wastewater flow reduction by the following
methods:
Contact cooling water recycle through cooling
towers.
- Holding tanks for all other process wastewater
subject to recycle.
Option C is based on:
Option B (chemical precipitation and sedimentation
preceded by flow reduction), plus multimedia
filtration.
Option D is based on:
Option C (chemical precipitation, sedimentation,
in-process flow reduction, and multimedia filtration);
plus, where required, activated alumina treatment and
activated carbon adsorption.
(This option was only considered for nonferrous phase I.)
Option E is based on:
Option C (chemical precipitation, sedimentation,
in-process flow reduction, and multimedia filtration);
plus activated carbon adsorption applied to the total
plant discharge as a polishing step.
Option F is based on:
Option C (chemical precipitation, sedimentation,
in-process flow reduction, and multimedia filtration);
plus reverse osmosis treatment to attain complete
recycle of all process wastewater.
(This option was only considered for nonferrous phase I.)
As a means of evaluating the economic achievability of each of
these treatment options, the Agency developed estimates of the
compliance costs and pollutant reduction benefits. An estimate
of capital and annual costs for the applicable BAT options was
prepared for each subcategory as an aid in choosing the best BAT
option. The cost estimates are presented in Section X of each of
the subcategory supplements. All costs are based on March 1982
dollars.
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The cost methodology has been described in detail in Section
VIII. For most treatment technologies, standard cost literature
sources were used for module capital and annual costs. Data from
several sources were combined to yield average or typical costs
as a function of flow or other characteristic design parameters.
In a small number of modules, the technical literature was
reviewed to identify the key design criteria, which were then
used as a basis for vendor contacts. The resulting costs for
individual pieces of equipment were combined to yield module
costs. In either case, the cost data were coupled with flow data
from each plant to establish system costs for each facility.
Pollutant reduction benefit estimates were calculated for each
option for each subcategory. The estimated pollutant removal
that the treatment technologies can achieve is presented in
Section X of each of the subcategory supplements.
The first step in the calculation of the benefit estimates is the
calculation of production normalized raw waste values (mg/kkg)
for each pollutant in each waste stream. The raw waste values
were calculated using one of three methods. When analytical con-
centration data (mg/1) and sampled production normalized flow
values (1/kkg) were available for a given waste stream, individ-
ual raw waste values for each sample were calculated and aver-
aged. This method allows for the retention of any relationship
between concentration, flow and production. When sampled produc-
tion normalized flows were not available for a given waste
stream, an average concentration was calculated for each pollu-
tant, and the average production normalized flow taken from the
dcp information for that waste stream was used to calculate the
raw waste. When analytical values were not available for a given
waste stream, the raw waste values for a stream of similar water
quality was used.
The total flow (1/yr) for each option for each subcategory was
calculated by first, comparing the actual discharge to the regu-
latory flow for each waste stream; second, selecting the smaller
of the two values; and third, summing the smaller flow values for
each waste stream in the subcategory for each option. The regu-
latory flow values were calculated by multiplying the total pro-
duction associated with each waste stream in each subcategory
(kkg/yr) by the appropriate production normalized flow (1/kkg)
for each waste stream for each option.
The raw waste mass values (kg/yr) for each pollutant in each sub-
category were calculated by summing individual raw waste masses
for each waste stream in the subcategory. The individual raw
waste mass values were calculated by multiplying the total pro-
duction associated with each waste stream in each subcategory
(kkg/yr) by the raw waste value (mg/kkg) for each pollutant in
each waste stream.
456
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The mass discharged (kg/yr) for each pollutant for each option
for each subcategory was calculated by multiplying the total flow
(1/yr) for those waste streams which enter the central treatment
system, by the treatment effectiveness concentration (mg/1)
(Table VII-21) for each pollutant for the appropriate option.
The total mass removed (kg/yr) for each pollutant for each option
for each subcategory was calculated by subtracting the total mass
discharged (kg/yr) from the total raw mass (kg/yr).
Total treatment performance values for each subcategory were cal-
culated by using the total production (kkg/yr) of all plants in
the subcategory for each waste stream. Treatment performance
values for direct dischargers in each subcategory were calculated
by using the total production (kkg/yr) of all direct dischargers
in the subcategory for each waste stream.
MODIFICATION OF EXISTING BAT EFFLUENT LIMITATIONS
Modifications to existing promulgated BAT effluent limitations
are being proposed or considered for bauxite refining and
metallurgical acid plants in the nonferrous metals manufacturing
category.
Allowances for Net Precipitation in Bauxite Refining
Promulgated BPT and BAT limitations for the bauxite refining sub-
category are based on use of settling impoundments. Facilities
in this subcategory are subject to a zero discharge requirement;
however, during any month they can discharge a volume of water
equal to the difference between precipitation that falls within
the impoundment and evaporation within that impoundment for that
month.
The Agency has proposed to retain the monthly net precipitation
allowance for bauxite refining. EPA is giving equal considera-
tion to establishment of concentration-based limitations on the
monthly discharge to control the discharge of phenolic based
toxic pollutants. Samples of red mud impoundment discharges
collected by EPA showed treatable concentrations of two phenolic
compounds, phenol and 2-chlorophenol. The concentration-based
limitations we are considering for phenol, 2-chlorophenol, and
phenolics (4-AAP) are based on carbon adsorption treatment of the
monthly discharge. We formally solicit comment on concentration-
based limitations for the net precipitation discharge allowance
for bauxite refining facilities.
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Metallurgical Acid Plants
As discussed in Section IX, the metallurgical acid plants sub-
category is being modified to include acid plants associated with
primary molybdenum roasters. This is based on the similarity
between discharge rates and effluent characteristics of waste-
waters from all metallurgical acid plants. The Agency is also
considering establishing effluent limitations for fluoride in
discharges from acid plants associated with primary molybdenum
operations and solicits comment on this action.
BAT OPTION SELECTION
The option generally selected throughout the category is Option C
- chemical precipitation, sedimentation, in-process flow reduc-
tion, and multimedia filtration, along with applicable pretreat-
ment, including ammonia steam stripping, cyanide precipitation,
and oil skimming. The Agency has selected BPT plus in-process
wastewater flow reduction and the use of filtration as an
effluent polishing step as BAT for all of the subcategories
except primary rare earth metals, where additional treatment is
proposed for the control of toxic organics.
This combination of treatment technologies has been selected
because they are technically feasible and are demonstrated within
the nonferrous metals manufacturing category. Implementation of
this treatment scheme would result in the removal of an estimated
336,461 kg/yr of toxic pollutants which is 1,133 kg/yr above BPT
discharge estimates. Although the Agency is not required to
balance the costs against effluent reduction benefits (see
Weyerhaeuser v. Costle, supra), the Agency has given substantial
weight to the reasonableness of cost. The Agency's current
economic analysis shows that this combination of treatment tech-
nologies is economically achievable. Price increases are not
expected to exceed 2.5 percent for any subcategory.
Of the 21 subcategories in nonferrous metals manufacturing phase
II, EPA has reserved setting BAT limitations for the following
five subcategories:
1. Primary Boron
2. Primary Cesium and Rubidium
3. Secondary Indium
4. Secondary Mercury
5. Secondary Nickel
In addition to the toxic limitations under consideration for
bauxite refining, effluent BAT limitations have been proposed for
the following 15 subcategories:
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1. Primary Antimony
2. Primary Beryllium
3. Primary and Secondary Germanium and Gallium
4. Primary Molybdenum and Rhenium
5. Secondary Molybdenum and Vanadium
6. Primary Nickel and Cobalt
7. Primary Precious Metals and Mercury
8. Secondary Precious Metals
9. Primary Rare Earth Metals
10. Secondary Tantalum
11. Primary and Secondary Tin
12. Primary and Secondary Titanium
13. Secondary Tungsten and Cobalt
14. Secondary Uranium
15. Primary Zirconium and Hafnium
The general approach taken by the Agency for BAT regulation of
this category and the BAT option selected for each subcategory is
presented below. The actual proposed limitations may be found in
Section II of this document.
Bauxite Refining
We are proposing today to make minor technical amendements to
delete or correct references to FDF considerations under Part 125
and pretreatment references to Part 128. The existing BAT (prom-
ulgated on April 8, 1974 under Subpart A of 40 CFR Part 421)
prohibits the discharge of process wastewater except for an
allowance for net precipitation that falls within process
wastewater impoundments.
Information has become available to the Agency that suggests the
need for treatment of the red mud impoundment effluent to remove
toxic organic pollutants not considered in the development of the
promulgated limitations. In keeping with the emphasis of the
Clean Water Act of 1977 on toxic pollutants, we have considered
the discharge from process wastewater impoundments as a part of
this rulemaking and are not considering the regulation of toxic
pollutants.
Therefore, we also are soliciting comments on the need for BAT
limitations on the net precipitation discharge from red-mud ponds
based on activated carbon treatment to remove toxic organic pol-
lutants. The pollutants being considered for control under BAT
are 2-chlorophenol, phenol (GC/MS), and total phenols (4-AAP).
The limitations would be based on achieving a daily maximum con-
centraton of 0.010 mg/1 for each pollutant. The toxic pollutants
2,4, 6-trichlorophenol, 4, 6-dichlorophenol, 2-nitrophenol, and
4-nitrophenol were also considered for possible regulation
because they were found at treatable concentrations in the raw
459
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wastewaters from this subcategory. These pollutants are not
presently being considered for regulation because they would be
effectively controlled by the toxic organic limitations presently
being considered.
The BAT limitations on the toxic pollutants under consideration
would remove annually an estimated 4,835 kg of toxic pollutants
from the estimated current discharge. Estimated capital cost for
achieving proposed BAT is $7.60 million, and annualized cost is
$2.98 million.
The Agency may promulgate concentration based BAT limitations as
discussed above for net precipitation discharge. Accordingly the
public should submit comments on this issue at this time. The
Agency specifically invites comments on the need to modify the
existing regulation. If EPA determines that a change in the
existing regulation is necessary, EPA intends to promulgate the
technical option discussed above.
Primary Antimony
Our proposed BAT limitations for this subcategory are based on
chemical precipitation and sedimentation (BPT technology) with
the addition of filtration.
The pollutants specifically limited under BAT are antimony,
arsenic, lead and mercury. The toxic pollutants cadmium, copper
and zinc were also considered for regulation because they were
found at treatable concentrations in the raw wastewaters from
this subcategory. These pollutants were not selected for
specific regulation because they will be effectively controlled
when the regulated toxic metals are treated to the levels
achievable by the model BAT technology.
Implementation of the proposed BAT limitations would remove annu-
ally an estimated 1.3 kg of toxic metals over the estimated BPT
discharge. Estimated capital cost for achieving proposed BAT is
$41,250, and annualized cost is $21,183.
Primary Beryllium
Our proposed BAT limitations for this subcategory are based on
chemical precipitation and sedimentation (BPT technology), with
the addition of in-process wastewater flow reduction and filtra-
tion. Flow reduction is based on 90 percent recycle of beryllium
oxide calcining furnace wet air pollution control. Although the
one beryllium plant currently generating beryllium oxide calcin-
ing furnace wet air pollution control wastewater does not prac-
tice recycle, recycle of similar streams is demonstrated exten-
sively in other subcategories of the nonferrous metals manufac-
turing category.
460
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The pollutants specifically limited under BAT are beryllium,
chromium, copper, and fluoride.
Implementation of the proposed BAT limitations would remove annu-
ally an estimated 8 kg of toxic metals over the estimated BPT
discharge. An intermediate option considered for BAT is flow
reduction plus chemical precipitation and sedimentation. This
option would remove an estimated 7.3 kg of toxic metals over the
estimated BPT discharge.
The costs and specific removal data for this subcategory are not
presented here because the data on which they are based has been
claimed to be confidential.
Primary and Secondary Germanium and Gallium
We are proposing Level A BAT limitations for this subcategory
based on chemical precipitation and sedimentation (BPT technol-
ogy) for plants that only reduce germanium dioxide in a hydrogen
furnace and then wash and rinse the germanium product in conjunc-
tion with zone refining. This is equivalent to BPT technology.
Level B BAT limitations are proposed for all other facilities in
the subcategory. The Level B effluent limitations are based on
Level A technology with the addition of filtration.
The pollutants specifically limited under BAT are arsenic, lead,
zinc, germanium, and fluoride. The toxic pollutants antimony,
cadmium, chromium, copper, nickel, selenium, silver and thallium
were also considered for regulation because they were found at
treatable concentrations in the raw wastewaters from this sub-
category. These pollutants were not selected for specific regu-
lation because they will be effectively controlled when the regu-
lated toxic metals are treated to the concentrations achievable
by the model BAT technology. The Agency considered applying the
same technology levels to this entire subcategory but decided to
propose this two tiered regulatory scheme because there was
little additional pollutant removal from the Level A wastewater
streams when treated by the added Level B technology.
Although there are no existing direct dischargers in this sub-
category, BAT is proposed for any existing zero discharger who
elects to discharge at some point in the future. This action was
deemed necessary because wastewaters from germanium and gallium
operations which contain significant loadings of toxic pollutants
are currently being dipsosed of in a RCRA permitted surface
impoundment.
The costs and specific removal data for this subcategory are not
presented here because the data on which they are based has been
claimed to be confidential.
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Primary Molybdenum and Rhenium
Our proposed BAT limitations for this subcategory are based on
preliminary treatment consisting of ammonia steam stripping,
end-of-pipe treatment consisting of chemical precipitation and
sedimentation, (BPT technology) with the addition of in-process
wastewater flow reduction and filtration. Flow reductions are
based on 90 percent recycle of scrubber liquor, a rate demon-
strated by one of the two direct discharger plants.
The pollutants specifically limited under BAT are arsenic, lead,
molybdenum, nickel, selenium, and ammonia. The toxic pollutants
chromium, copper, and zinc were also considered for regulation
because they were found at treatable concentrations in the raw
wastewaters from this subcategory. These pollutants were not
selected for specific regulation because they will be effectively
controlled when the regulated toxic metals are treated to the
levels achievable by the model BAT technology.
Implementation of the proposed BAT limitations would remove annu-
ally an estimated 24 kg of toxic metals greater than the esti-
mated BPT removal. No additional ammonia is removed at BAT.
An intermediate option considered for BAT is preliminary treat-
ment with ammonia steam stripping followed by end-of-pipe treat-
ment consisting of chemical precipitation and sedimentation with
the addition of flow reduction. This option would remove an
estimated 13 kg of toxic metals more than the estimated BPT
discharge.
The costs and specific removal data for this subcategory are not
presented here because the data on which they are based has been
claimed to be confidential.
We are expanding the applicability of the existing BAT limita-
tions for metallurgical acid plants to include acid plants
associated with primary molybdenum roasting operations. The
existing BAT limitations are based on the BPT technology (lime
precipitation and sedimentation), in-process wastewater reduc-
tion, sulfide precipitation and filtration. Flow reduction is
based on 90 percent recycle of scrubber liquor.
Compliance with the BAT limitations for the existing metallur-
gical acid plants subcategory by the two direct discharging
primary molybdenum facilities which operate sulfuric acid plants
will result in the annual removal of an estimated 219 kg of toxic
pollutants more than the estimated BPT removal.
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Secondary Molybdenum and Vanadium
Our proposed BAT limitations for this subcategory are based on
preliminary treatment consisting of ammonia steam stripping fol-
lowed by end-of-pipe treatment consisting of chemical precipita-
tion and sedimentation (BPT technology) and filtration.
The pollutants specifically limited under BAT are antimony, lead,
molybdenum, nickel, and ammonia. The toxic pollutants arsenic,
beryllium, cadmium, chromium and zinc were also considered for
regulation because they were found at treatable concentrations in
the raw wastewaters from this subcategory. These pollutants were
not selected for specific regulation because they will be effec-
tively controlled when the regulated toxic metals are treated to
the concentrations achievable by the model BAT technology.
Implementation of the proposed BAT limitations would remove annu-
ally an estimated 80 kg of toxic metals greater than the esti-
mated BPT removal.
The costs and specific removal data for this subcategory are not
presented here because the data on which they are based has been
claimed to be confidential.
Primary Nickel and Cobalt
Our proposed BAT limitations for this subcategory are based on
preliminary treatment consisting of ammonia steam stripping fol-
lowed by end-of-pipe treatment consisting of chemical precipita-
tion and sedimentation (BPT technology), and filtration. A fil-
ter is presently utilized by the one plant in this subcategory.
The pollutants specifically limited under BAT are cobalt, copper,
nickel, and ammonia. The toxic pollutant zinc was also con-
sidered for regulation because it was found at treatable concen-
trations in the raw wastewaters from this subcategory. This pol-
lutant was not selected for specific regulation because it will
be effectively controlled when the regulated toxic metals are
treated to the levels achievable by the model BAT technology.
Implementation of the proposed BAT limitations would remove annu-
ally an estimated 5 kg of toxic metals greater than the estimated
BPT removal.
The costs and specific removal data for this subcategory are not
presented her«> because the data on which they are based has been
claimed to be confidential.
463
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Primary Precious Metals and Mercury
Our proposed BAT limitations for this subcategory are based on
preliminary treatment consisting of oil skimming and end-of-pipe
treatment consisting of chemical precipitation and sedimentation
(BPT technology), with the addition of in-process wastewater flow
reduction and filtration.
The pollutants specifically limited under BAT are arsenic, lead,
mercury, silver, and zinc. The toxic pollutants cadmium,
chromium, copper, nickel and thallium were also considered for
regulation because they were found at treatable concentrations in
the raw wastewaters from this subcategory. These pollutants were
not selected for specific regulation because they will be effec-
tively controlled when the regulated toxic metals are treated to
the levels achievable by the model BAT technology.
Implementation of the proposed BAT limitations would remove annu-
ally an estimated 0.5 kg of toxic metals greater than the esti-
mated BPT removal. Estimated capital cost for achieving proposed
BAT is $30,000, and annualized cost is $10,000.
Secondary Precious Metals
Our poposed BAT limitations for this subcategory are based on
preliminary treatment consisting of cyanide precipitation and
ammonia steam stripping and end-of-pipe treatment consisting of
chemical precipitation and sedimentation (BPT technology) with
the addition of in-process wastewater flow reduction and filtra-
tion. Flow reductions are based on recycle of scrubber effluent.
Twenty-one of the 29 existing plants currently have scrubber
liquor recycle rates of 90 percent or greater. A filter is also
presently utilized by one plant in the subcategory.
The pollutants specifically limited under BAT are copper, cya-
nide, zinc, and ammonia. The toxic pollutants antimony, arsenic,
cadmium, chromium, lead, nickel, selenium, silver and thallium
were also considered for regulation because they were found at
treatable concentrations in the raw wastewaters from this
subcategory. These pollutants were not selected for specific
regulation because they will be effectively controlled when the
regulated toxic metals are treated to the levels achievable by
the model BAT technology.
Implementation of the proposed BAT limitations would remove annu-
ally an estimated 10 kg of toxic pollutants greater than the
estimated BPT removal. No additional ammonia or cyanide is
removed at BAT.
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An intermediate option considered for BAT is flow reduction plus
preliminary treatment consisting of cyanide precipitation ammonia
steam stripping, and end-of-pipe treatment consisting of chemical
precipitation and sedimentation. This option would remove an
estimated 6.3 kg of toxic metals more than the estimated BPT
removal.
The costs and specific removal data for this subcategory are not
presented here because the data on which they are based has been
claimed to be confidential.
Primary Rare Earth Metals
Our proposed BAT limitations for this subcategory are based on
chemical precipitation and sedimentation (BPT technology) with
the addition of in-process wastewater flow reduction, filtration
and activated carbon adsorption. Flow reduction is based on 90
percent recycle of scrubber effluent. Activated carbon technol-
ogy is transferred from the iron and steel category where it is a
demonstrated technology for removal of toxic organics.
The pollutants specifically limited under BAT are hexachloro-
benzene, chromium, lead, and nickel. The toxic pollutants
benzene, arsenic, cadmium, copper, selenium, silver, thallium,
and zinc were also considered for regulation because they were
found at treatable concentrations in the raw wastewaters from
this subcategory. These pollutants were not selected for
specific regulation because they will be effectively controlled
when the regulated toxic pollutants are treated to the levels
achievable by the model BAT technology.
Implementation of the proposed BAT limitations would remove annu-
ally an estimated 18.3 kg of toxic pollutants (14.9 kg of toxic
organics and 3.4 kg of toxic metals) and 198 kg of suspended
solids more than the estimated BPT removal. An intermediate
option considered for BAT is chemical precipitation and sedimen-
tation with the addition of in-process flow reduction and filtra-
tion. This option would remove an estimated 3.4 kg of toxic
metals more than the estimated BPT removal. No toxic organics
would be removed.
The costs and specific removal data for this subcategory are not
presented here because the data on which they are based has been
claimed to be confidential.
Secondary Tantalum
Our proposed BAT limitations for this subcategory are based on
chemical precipitation and sedimentation (BPT technology) with
the addition of filtration.
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The pollutants specifically limited under BAT are copper, lead,
nickel, and zinc. The toxic pollutants antimony, beryllium,
cadmium, chromium, and silver were also considered for regulation
because they were found at treatable concentrations in the raw
wastewaters from this subcategory. These pollutants were not
selected for specific regulation because they will be effectively
controlled when the regulated toxic metals are treated to the
levels achievable by the model BAT technology.
Implementation of the proposed BAT limitations would remove annu-
ally an estimated 4.8 kg of toxic metals more than the estimated
BPT removal.
The costs and specific removal data for this subcategory are not
presented here because the data on which they are based has been
claimed to be confidential.
Primary and Secondary Tin
Our proposed BAT limitations for this subcategory are based on
preliminary treatment consisting of ammonia steam stripping and
cyanide precipitation when required, and end-of-pipe treatment
consisting of chemical precipitation and sedimentation (BPT tech-
nology), with the addition of filtration.
The pollutants specifically limited under BAT are antimony,
cyanide, lead, nickel, tin, ammonia, and fluoride. The toxic
pollutants arsenic, cadmium, chromium, copper, selenium, silver,
thallium, and zinc were also considered for regulation because
they were found at treatable concentrations in the raw waste-
waters from this subcateogry. These pollutants were not selected
for specific regulation because they will be effectively control-
led when the regulated toxic metals are treated to the. levels
achievable by the model BAT technology.
Implementation of the proposed BAT limitations would remove annu-
ally an estimated 91 kg of toxic metals over the estimated BPT
discharge. No additional fluoride is removed at BAT. The costs
and specific removal data for this subcategory are not presented
here because the data on which they are based has been claimed to
be confidential.
Primary and Secondary Titanium
We are proposing Level A BAT limitations for titanium plants
which do not practice electrolytic recovery of magnesium and
which use vacuum distillation instead of leaching to purify
titanium sponge. Level A BAT limitations are based on chemical
precipitation, sedimentation, and oil skimming (BPT technology)
plus in-process wastewater flow reduction. Level B BAT limita-
tions are proposed for all other titanium plants and are based on
466
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chemical precipitation, sedimentation, and oil skimming pretreat-
ment where required (BPT technology) plus flow reduction, and
filtration. Flow reduction is based on 90 percent recycle of
scrubber effluent through holding tanks and 90 percent recycle of
casting contact cooling water through cooling towers. The Agency
considered applying the same technology levels to this entire
subcategory but decided to propose this two tiered regulatory
scheme because there was little additional pollutant removal from
the Level A wastewater streams when treated by the added Level B
technology.
The pollutants specifically limited under BAT are chromium, lead,
nickel, thallium, titanium and fluoride. The toxic pollutants
antimony, cadmium, copper and zinc were also considered for regu-
lation because they were found at treatable concentrations in the
raw wastewaters from this subcategory. These pollutants were not
selected for specific regulation because they will be effectively
controlled when the regulated toxic metals are treated to the
levels achievable by the model BAT technology.
There are currently no direct discharging Level A plants in this
subcategory. It is estimated that if the four existing direct
discharging Level B plants in this subcategory became Level A
dischargers they would incur a capital cost of approximately
$641,000 and an annualized cost of $325,000; 130 kg of toxic
pollutants would be removed.
Implementation of the proposed Level B BAT limitations would
remove annually an estimated 211 kg of toxic polultants more than
estimated BPT removal. Estimated capital cost for achieving
proposed BAT is $1,030,000, and annualized cost is $585,000.
Secondary Tungsten and Cobalt
Our proposed BAT limitations for this subcategory are based on
preliminary treatment consisting of ammonia steam stripping and
oil skimming, and end-of-pipe treatment consisting of chemical
precipitation and sedimentation (BPT technology), plus in-process
wastewater flow reduction and filtration. Flow reductions are
based on 90 percent recycle of scrubber effluent, which is the
rate reported by the only existing plant with a scrubber.
The pollutants specifically limited under BAT are cobalt, copper,
nickel, and ammonia. The toxic pollutants arsenic, cadmium,
chromium, lead, silver, and zinc were also considered for regula-
tion because they were found at treatable concentrations in the
raw wastewaters from this subcategory. These pollutants were not
selected for specific regulation because they will be effectively
controlled when the regulated toxic metals are treated to the
levels achievable by the model BAT technology.
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Implementation of the proposed BAT limitations would remove annu-
ally an estimated 48 kg of toxic pollutants more than estimated
BPT removal.
The costs and specific removal data for this subcategory are not
presented here because the data on which they are based has been
claimed to be confidential.
The intermediate option we considered for BAT is flow reduction
plus ammonia steam stripping, oil skimming, and chemical precipi-
tation and sedimentation. This option would remove an estimated
26 kg of toxic metals over the estimated BPT discharge.
Secondary Uranium
Our proposed BAT limitations for this subcategory are based on
preliminary treatment consisting of ammonia steam stripping and
end-of-pipe treatment consisting of chemical precipitation and
sedimentation (BPT technology), plus filtration.
The pollutants specifically limited under BAT are chromium, cop-
per, nickel, ammonia, uranium and fluoride. The toxic pollu-
tants arsenic, cadmium, lead, selenium, silver and zinc were also
considered for regulation because they were found at treatable
concentrations in the raw wastewaters from the subcategory.
These pollutants were not selected for specific regulation
because they will be effectively controlled when the regulated
toxic metals are treated to the levels achievable by the model
BAT technology.
Implementation of the proposed BAT limitations would remove
annually an estimated 24 kg of toxic metals more than estimated
BPT removal. Estimated capital cost for achieving proposed BAT
is $54,312, and annualized cost is $86,452 (1982 dollars).
Primary Zirconium and Hafnium
Our proposed Level A BAT limitations for plants which only pro-
duce zirconium or zirconium-nickel alloys by magnesium reduction
of Zr02 are based on barium chloride coprecipitation, cyanide
precipitation and ammonia steam stripping pretreatment and chemi-
cal precipitation and sedimentation (BPT technology), plus
in-process wastewater flow reduction. Level B limitations apply
to all other plants in the subcategory. The proposed Level B BAT
limitations are based on barium chloride coprecipitation, cyanide
precipitation, ammonia steam stripping and chemical precipitation
and sedimentation (BPT technology), plus in-process wastewater
flow reduction and filtration.
468
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Flow reductions are based on 90 percent recycle of scrubber
effluent. The Agency considered applying the same technology
levels to this entire subcategory but decided to propose this two
tiered regulatory scheme because there was little additional
pollutant removal from the Level A wastewater streams when
treated by the added Level B technology.
The pollutants specifically limited under BAT are chromium, cya-
nide, lead, nickel, radium (226) and ammonia. The toxic pollu-
tants cadmium, thallium and zinc were also considered for regu-
lation because they were found at treatable concentrations in the
raw wastewaters from this subcategory. These polutants were not
selected for specific regulation because they will be effectively
controlled when the regulated toxic metals are treated to the
levels achievable by the model BAT technology.
There are currently no Level A direct discharging plants in this
subcategory. The one Level B direct discharger complying with
BAT would remove 515 kg/yr of toxic pollutants more than esti-
mated BPT removal.
The costs and specific removal data for this subcategory are not
presented here because the data on which they are based has been
claimed to be confidential.
REGULATED POLLUTANT PARAMETERS
Presented in Section VI of this document is a list of the pollu-
tant parameters at concentrations and frequencies above treatable
concentrations that warrant further consideration. Although
these pollutants were found at treatable concentrations, the
Agency is not proposing to regulate each pollutant selected for
further consideration. The high cost associated with analysis of
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 reduction
benefit 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
469
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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.
Filtration as part of the technology basis is likewise justified
because this technology removes metals non-preferentially.
The same arguments stated above also apply to activated carbon
adsorption for the primary rare earth metals subcategory. Two
aromatic hydrocarbons were found above treatable concentrations
in the primary rare earth metals subcategory. Since these
organic pollutants are structurally similar, the Agency believes
that by regulating the toxic organic in the largest quantity, the
other toxic organic will be effectively controlled.
The conventional pollutants oil and grease, pH, and TSS are
excluded from regulation in BAT. They are regulated by BCT.
Table X-2 (page 473) presents the pollutants selected for
specific regulation in BAT and Table X-3 (page 475) presents
those pollutants that are effectively controlled by technologies
upon which are based other effluent limitations and guidelines.
A more detailed discussion on the selection and exclusion of
toxic pollutants is presented in Sections VI and X of each
subcategory supplement.
EXAMPLES OF BUILDING BLOCK APPROACH IN DEVELOPING PERMITS
The building block approach is only to be used when the individ-
ual discharger combines wastewater from various processes and
co-treats the wastewater before discharge through a single dis-
charge pipe. The building block approach allows the determina-
tion of appropriate effluent limitations for the discharge point
by combining appropriate limitations based upon the various
processes that contribute wastewater to the discharge point.
As an example, consider a facility which refines tin from both
new scrap and municipal solid waste scrap. The sources of waste-
water in this example are dealuminizing rinse, spent electrowin-
ning solution from new scrap and spent electrowinning solution
from municipal solid waste. By multiplying the production calcu-
lated according to 40 CFR 122.63(b)(2) for each of these opera-
tions by the limitations or standards in 40 GFR 42a.293 for the
three waste streams and by summing the production obtained for
each of these waste streams, the permit writer can obtain the
allowable mass discharge.
If, for example, the production associated with the dealuminizing
rinse, the production of dealuminized scrap, is 450,000 kg/yr,
the production associated with the spent electrowinning solution
from new scrap, the production of electrolytic tin from new
470
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scrap, is 125,000 kg/yr, and the municipal solid waste scrap
processed associated with spent electrowinning solution from
municipal solid waste is 450,000 kg/yr, the maximum for any one
day limitation based on the best available technology economi-
cally achievable (BAT) for the pollutant nickel is 11,589 kg/yr
as calculated below:
Dealuminizing Rinse
(450,000 kg/yr)(0.019 mg/kg)(10-6 kg/mg) - 0.009 kg/yr
Spent Electrowinning Solution From New Scrap
(125,000 kg/yr)(9.240 mg/kg)(10-6 kg/mg) = 11.55 kg/yr
Spent Electrowinning Solution From Municipal Solid Waste
(450,000 kg/yr)(0.065 mg/kg)(10~6 kg/mg) = 0.030
TOTAL = 11.589
471
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Table X-1
BAT OPTIONS CONSIDERED FOR EACH OF THE NONFERROUS
METALS MANUFACTURING SUBCATEGORIES
Options Considered
Subcategory A B C D E
Bauxite Refining X
Primary Antimony X X
Primary Beryllium XXX
Primary Boron X X
Primary Cesium and Rubidium X X
Primary and Secondary X X
Germanium and Gallium
Secondary Indium X X
Secondary Mercury X X
Primary Molybdenum and Rhenium XXX
Secondary Molybdenum and X X
Vanadium
Primary Nickel and Cobalt X X
Secondary Nickel - X X
Primary Precious Metals and XXX
Mercury
Secondary Precious Metals X X X
Primary Rare Earth Metals XXX X
Secondary Tantalum X X
Primary and Secondary Tin X X
Primary and Secondary Titanium XXX
Secondary Tungsten and Cobalt XXX
Secondary Uranium X X
Primary Zirconium and Hafnium XXX
472
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Table X-2
BAT REGULATED POLLUTANT PARAMETERS
Subcategory
Primary Antimony
Bauxite Refining
(As discussed earlier, the Agency
is considering effluent limitations
for discharges from bauxite red mud
impoundments. To assist the public
in providing comment on this issue,
we are providing information in this
table on the bauxite subcategory)
Primary Beryllium
Primary and Secondary Germanium
and Gallium
Pollutant Parameters
Primary Molybdenum and Rhenium
Secondary Molybdenum and Vanadium
Primary Nickel and Cobalt
Primary Precious Metals and Mercury
114.
115.
122.
123.
24.
65.
117.
119.
120.
115.
122.
128.
115.
122.
124.
125.
114.
122.
124.
120.
124.
115.
122.
123.
126.
128.
antimony
arsenic
lead
mercury
[2-chlorophenol]
[phenol]
[phenols (4-AAP)]
beryllium
chromium (total)
copper
fluoride
arsenic
lead
zinc
fermanium
luoride
arsenic
lead
nickel
selenium
molybdenum
ammonia (as N)
antimony
lead
nickel
molybdenum
ammonia (as N)
copper
nickel
cobalt
ammonia (as N)
arsenic
lead
mercury
silver
zinc
473
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Table X-2 (Continued)
BAT REGULATED POLLUTANT PARAMETERS
Subcategory
Secondary Precious Metals
Primary Rare Earth Metals
Secondary Tantalum
Primary and Secondary Tin
Primary and Secondary Titanium
Secondary Tungsten and Cobalt
Secondary Uranium
Primary Zirconium and Hafnium
Pollutant Parameters
120. copper
121. cyanide
128. zinc
ammonia (as N)
9. hexachlorobenzene
119. chromium (total)
122. lead
124. nickel
120. copper
122. lead
124. nickel
128. zinc
114. antimony
121. cyanide
122. lead
124. nickel
tin
fluoride
ammonia (as N)
119. chromium (total)
122. lead
124. nickel
127. thallium
fluoride
titanium
120. copper
124. nickel
cobalt
ammonia (as N)
119. chromium (total)
120. copper
124. nickel
uranium
ammonia (as N)
fluoride
119. chromium (total)
121. cyanide (total)
122. lead
124. nickel
radium 226
ammonia (as N)
474
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Table X-3
TOXIC POLLUTANTS EFFECTIVELY CONTROLLED BY TECHNOLOGIES UPON
WHICH OTHER EFFLUENT LIMITATIONS AND GUIDELINES ARE BASED
Subcategory
Bauxite Refining
(As discussed earlier, the Agency
is considering effluent limitations
for discharges from bauxite red mud
impoundments. To assist the public
in providing comment on this issue,
we are providing information in this
table on the bauxite subcategory)
Primary Antimony
Primary Boron
Primary Cesium and Rubidium
Pollutant Parameters
Primary and Secondary Germanium
and Gallium
Secondary Indium
21.
31.
57.
58.
118.
120.
128.
118.
119.
127.
128.
114.
115.
117.
118.
119.
120.
124.
126.
114.
118.
119.
120.
122.
124.
125.
126.
127.
119.
124.
125.
126.
127.
[2,4,6-trichlorophenol]
[2,4-d ichlorophenol]
[2-nitrophenol]
[4-nitrophenol]
cadmium
copper
zinc
cadmium
chromium (total)
thallium
zinc
antimony
arsenic
beryllium
cadmium
chromium (total)
copper
nickel
silver
antimony
cadmium
chromium
copper
lead
nickel
selenium
silver
thallium
chromium
nickel
selenium
silver
thallium
475
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Table X-3 (Continued)
TOXIC POLLUTANTS EFFECTIVELY CONTROLLED BY TECHNOLOGIES UPON
WHICH OTHER EFFLUENT LIMITATIONS AND GUIDELINES ARE BASED
Subcategory
Secondary Mercury
Pollutant Parameters
Primary Molybdenum and Rhenium
Secondary Molybdenum and Vanadium
Primary Nickel and Cobalt
Secondary Nickel
Primary Precious Metals and
Mercury
Secondary Precious Metals
115.
118.
120.
126.
128.
119.
120.
128.
115.
117.
118.
119.
128.
128.
115.
128.
118.
119.
120.
124.
125.
127.
114.
115.
118.
119.
122.
124.
125.
126.
127.
arsenic
cadmium
copper
silver
zinc
chromium (total)
copper
zinc
arsenic
beryllium
cadmium
chromium
zinc
zinc
arsenic
zinc
cadmium
chromium
copper
nickel
selenium
thallium
antimony
arsenic
cadmium
chromium
lead
nickel
selenium
silver
thallium
476
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Table X-3 (Continued)
TOXIC POLLUTANTS EFFECTIVELY CONTROLLED BY TECHNOLOGIES UPON
WHICH OTHER EFFLUENT LIMITATIONS AND GUIDELINES ARE BASED
Subcategory
Primary Rare Earth Metals
Secondary Tantalum
Primary and Secondary Tin
Primary and Secondary Titanium
Secondary Tungsten and Cobalt
Pollutant Parameters
6.
23.
48.
49.
51.
66.
115.
118.
120.
125.
126.
127.
128.
114.
117.
118.
119.
126.
115.
118.
119.
120.
125.
126.
127.
128.
114.
118.
120.
128.
115.
118.
119.
122.
126.
128.
carbon tetrachloride
(tetrachlorome thane)
chloroform
(trichlorome thane)
dichlorobromomethane
trichlorofluoro-
methane (deleted)
chlorodibromome thane
bis(2-ethylhexyl)
phthalate
arsenic
cadmium
copper
selenium
silver
thallium
zinc
antimony
beryllium
cadmium
chromium (total)
silver
arsenic
cadmium
chromium
copper
selenium
silver
thallium
zinc
antimony
cadm ium
copper
zinc
arsenic
cadmium
chromium
lead
silver
zinc
477
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Table X-3 (Continued)
TOXIC POLLUTANTS EFFECTIVELY CONTROLLED BY TECHNOLOGIES UPON
WHICH OTHER EFFLUENT LIMITATIONS AND GUIDELINES ARE BASED
Subcategory Pollutant Parameters
Secondary Uranium 115. arsenic
118. cadmium
122. lead
125. selenium
126. silver
128. zinc
Primary Zirconium and Hafnium 118. cadmium
127. thallium
128. zinc
478
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SECTION XI
NEW SOURCE PERFORMANCE STANDARDS
The basis for new source performance standards (NSPS) under
Section 306 of the Clean Water Act is the best available demon-
strated technology (BDT). New plants have the opportunity to
design the best and most efficient production processes and
wastewater treatment technologies. Therefore, NSPS includes pro-
cess changes, in-plant controls (including elimination of waste-
water discharges for some streams), operating procedure changes,
and end-of-pipe treatment technologies to reduce pollution to the
maximum extent possible. This section describes the control
technology for treatment of wastewater from new sources and
presents mass discharge limitations of regulated pollutants for
NSPS, based on the described control technology.
TECHNICAL APPROACH TO NSPS
All wastewater treatment technologies applicable to a new source
in the nonferrous metals manufacturing category have been consid-
ered previously for the BAT options. For this reason, six
options were considered as the basis for NSPS, all identical to
BAT options in Section X. In summary, the treatment technologies
considered for nonferrous metals manufacturing phase II new
facilities are outlined below:
Option A is based on:
Chemical precipitation of metals followed by sedimenta-
tion, and, where required, cyanide precipitation,
ammonia steam stripping, and oil skimming.
Option B is based on:
Option A (chemical precipitation and sedimentation)
plus process wastewater flow reduction by the following
methods:
- Contact cooling water recycle through cooling
towers.
Holding tanks for all other process wastewater
subject to recycle.
Option C is based on:
Option B (chemical precipitation and sedimentation
preceeded by flow reduction), plus multimedia
filtration.
479
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Option D is based on:
Option C (chemical precipitation, sedimentation,
in-process flow reduction, and multimedia filtration);
plus, where required, activated alumina treatment and
activated carbon adsorption. This option was only
considered for nonferrous phase I.
Option E is based on:
Option C (chemical precipitation, sedimentation,
in-process flow reduction, and multimedia filtration);
plus activated carbon adsorption applied to the total
plant discharge as a polishing step.
Option F is based on:
Option C (chemical precipitation, sedimentation,
in-process flow reduction, and multimedia filtration);
plus reverse osmosis treatment to attain complete
recycle of all process wastewater. This option was
only considered for nonferrous phase I.
The options listed above are general and can be applied to all
subcategories. Wastewater flow reduction within the nonferrous
metals manufacturing category is generally based on the recycle
of scrubbing liquors and casting contact cooling water. Addi-
tional flow reduction is achievable for new sources through
alternative process methods which are subcategory-specific.
Additional flow reduction attainable for each subcategory is
discussed later in this section regarding the NSPS option
selection.
For several subcategories, the regulatory production normalized
flows for NSPS are the same as the production normalized flows
for the selected BAT option. The mass of pollutant allowed to be
discharged per mass of product is calculated by multiplying the
appropriate treatment effectiveness value (one day maximum and
10-day average values) (mg/1) by the production normalized flows
(1/kkg). When these calculations are performed, the mass-based
NSPS can be derived for the selected option. Effluent concentra-
tions attainable by the NSPS treatment options are identical to
those presented in Section VII of the General Development
Document (Table VII-21, p. 311 ).
480
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MODIFICATIONS TO EXISTING NSPS
Metallurgical Acid Plants
As discussed in Section IX, the metallurgical acid plants sub-
category is being modified to include acid plants associated with
primary molybdenum roasters. This is based on the similarity
between discharge rates and effluent characteristics of waste-
waters from all metallurgical acid plants.
NSPS OPTION SELECTION
In general, EPA is proposing that the best available demonstrated
technology be equivalent to BAT technology (NSPS Option C). For
the subcategories where EPA has reserved setting BAT limitations,
chemical precipitation, sedimentation, and filtration is gener-
ally selected as the technology basis for NSPS. The principal
treatment method for this Option C is in-process flow reduction,
chemical precipitation, sedimentation, and multimedia filtration.
Option C also includes sulfide precipitation, cyanide precipita-
tion, ammonia steam stripping, and oil skimming, where required.
As discussed in Sections IX and X, these technologies are cur-
rently used at plants within this point source category. The
Agency recognizes that new sources have the opportunity to imple-
ment more advanced levels of treatment without incurring the
costs of retrofit equipment, and the costs of partial or complete
shutdown to install new production equipment. Specifically, the
design of new plants can be based on recycle of contact cooling
water through cooling towers, recycle of air pollution control
scrubber liquor or the use of dry air pollution control
equipment.
The data relied upon for selection of NSPS were primarily the
data developed for existing sources which included costs on a
plant-by-plant basis along with retrofit costs where applicable.
The Agency believes that compliance costs could be lower for new
sources than the cost estimates for equivalent existing sources,
because production processes can be designed on the basis of
lower flows and there will be no costs associated with retrofit-
ting the in-process controls. Therefore, new sources will have
costs that are not greater than the costs that existing sources
would incur in achieving equivalent pollutant discharge reduc-
tion. Based on this analysis, the Agency believes that the
selected NSPS (NSPS Option C) is an appropriate choice.
Section II of this document presents a summary of the NSPS for
the Nonferrous Metals Manufacturing Point Source Category. The
pollutants selected for regulation for each subcategory are
identical to those selected for BAT. Presented below is a brief
discussion describing the technology option selected for NSPS for
each subcategory.
481
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Bauxite Refining
The standards we are considering for NSPS would require that new
bauxite refining plants achieve a maximum daily concentration of
0.010mg/l for 2-chlorophenol, phenol, and phenols (4-AAP).
Because the NSPS being considered is equal to the BAT we are con-
sidering, we believe that the NSPS under consideration will not
pose a barrier to the entry of new plants into this subcategory,
Primary Antimony
We have proposed that NSPS be equal to BAT. Our review of the
subcategory indicates that no new demonstrated technologies that
improve on BAT technology exist. We do not believe that new
plants could achieve any flow reduction beyond the allowances
proposed for BAT. Because NSPS is equal to BAT, we believe that
the proposed NSPS will not pose a barrier to the entry of new
plants into this subcategory.
Primary Beryllium
We have proposed that NSPS be equal to BAT. Our review of the
subcategory indicates that no new demonstrated technologies that
improve on BAT technology exist. We do not believe that new
plants could achieve any flow reduction beyond the allowances
proposed for BAT. Because NSPS is equal to BAT, we believe that
the proposed NSPS will not have a detrimental impact on the entry
of new plants into this subcategory.
Primary Boron
Our proposed NSPS limitations for this subcategory are based on
chemical precipitation and sedimentation technology. This tech-
nology is fully demonstrated in many nonferrous metals subcate-
gories and would be expected to perform at the same level in this
subcategory.
The pollutants specifically limited under NSPS are boron, lead,
nickel, TSS, and pH. The toxic pollutants cadmium, chromium,
thallium, and zinc were also considered for regulation because
they are present at treatable concentrations in the raw waste-
waters from this subcategory. These pollutants were not selected
for specific regulation because they will be effectively con-
trolled when the regulated toxic metals are treated to the levels
achievable by the model technology.
The costs and specific removal data lor this subcategory are not
presented here because the data on which they are based has been
claimed to be confidential. We believe that the proposed NSPS
are achievable, and that they are not a barrier to entry of new
plants into this subcategory.
482
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Primary Cesium and Rubidium
Our proposed NSPS for the primary cesium and rubidium subcategory
are based on chemical precipitation, sedimentation, and filtra-
tion technology.
The pollutants and pollutant parameters specifically limited
under NSPS are lead, thallium, zinc, TSS, and pH. The toxic
pollutants antimony, arsenic, beryllium, cadmium, chromium,
copper, nickel, and silver were also considered for regulation
because they are present at treatable concentrations in the raw
wastewaters from this subcategory. These pollutants were not
selected for specific regulation because they will be effectively
controlled when the regulated toxic metals are treated to the
levels achievable by the model technology.
The costs and specific removal data for this subcategory are not
presented here because the data on which they are based has been
claimed to be confidential. We believe the proposed NSPS are
economically achievable, and that they are not a barrier to entry
of new plants into this subcategory.
Primary and Secondary Germanium and Gallium
We have proposed that NSPS be equal to BAT. Our review of the
subcategory indicates that no new demonstrated technologies that
improve on BAT technology exist. We do not believe that new
plants could achieve any flow reduction beyond the allowances
proposed for BAT. Because NSPS is equal to BAT, we believe that
the proposed NSPS will not have a detrimental impact on the entry
of new plants into this subcategory.
Secondary Indium
We are proposing that NSPS for the secondary indium subcategory
be based on chemical precipitation, sedimentation, (the same
model technology as PSES) and polishing filtration. The pollu-
tants and pollutant parameters specifically limited under NSPS
are cadmium, lead, zinc, indium, total suspended solids, and pH.
The toxic pollutants chromium, nickel, selenium, silver, and
thallium were also considered for regulation because they are
present at treatable concentrations in the raw wastewaters from
this subcategory. These pollutants were not selected for spe-
cific regulation because they will be effectively controlled when
the regulated toxic metals are treated to the levels achievable
by the model technology.
The costs and specific removal data for this subcategory are not
presented here because the data on which they are based has been
claimed to be confidential. We believe the proposed NSPS are
483
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economically achievable, and that they do not pose a barrier to
entry of new plants into this subcategory.
Secondary Mercury
Our proposed NSPS for this subcategory are based on chemical
precipitation, sedimentation, and filtration. This technology is
fully demonstrated in many nonferrous metals manufacturing sub-
categories and would be expected to perform at the same level in
this subcategory.
The pollutants specifically limited under NSPS are lead, mercury,
TSS, and pH. The toxic pollutants arsenic, cadmium, copper,
silver, and zinc were also considered for regulation because they
are present at treatable concentrations in the raw wastewaters
from this subcategory. These pollutants were not selected for
specific regulation because they will be effectively controlled
when the regulated toxic metals are treated to the levels achiev-
able by the model technology.
We believe the proposed NSPS are economically achievable, and
that they are not a barrier to entry of new plants into this
subcategory.
Primary Molybdenum and Rhenium
We have proposed that NSPS be equal to BAT. Our review of the
subcategory indicates that no new demonstrated technologies that
improve on BAT technology exist. We do not believe that new
plants could achieve any flow reduction beyond the allowances
proposed for BAT. Because NSPS are equal to BAT, we believe that
the proposed NSPS will not have a detrimental impact on the entry
of new plants into this subcategory.
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 opera-
tions. We do not believe that this expanded applicability will
have a detrimental impact on the entry of new plants into this
subcategory.
Secondary Molybdenum and Vanadium
We have proposed that NSPS be equal to BAT. Our review of the
subcategory indicates that no new demonstrated technologies that
improve on BAT technology exist. We do not believe that new
plants could achieve any flow reduction beyond the allowances
proposed for BAT. Because NSPS are equal to BAT, we believe that
the proposed NSPS will not pose a barrier to the entry of new
plants into this subcategory.
484
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Primary Nickel and Cobalt
We have proposed that NSPS be equal to BAT. Our review of the
subcategory indicates that no new demonstrated technologies that
improve on BAT technology exist. We do not believe that new
plants could achieve any flow reduction beyond the allowances
proposed for BAT. Because NSPS are equal to BAT, we believe that
the proposed NSPS will not pose a barrier to the entry of new
plants into this subcategory.
Secondary Nickel
We have proposed that NSPS be equivalent to PSES. Our review of
the subcategory indicates that no new demonstrated technologies
that improve on PSES technology exist. We do not believe that
new plants could achieve any flow reduction beyond the allowances
proposed for PSES. Because NSPS are equal to PSES, we believe
that the proposed NSPS will not pose a barrier to the entry of
new plants into this subcategory.
Primary Precious Metals and Mercury
We have proposed that NSPS be equal to BAT. Our review of the
subcategory indicates that no new demonstrated technologies that
improve on BAT technology exist. We do not believe that new
plants could achieve any flow reduction beyond the allowances
proposed for BAT. Because NSPS are equal to BAT, we believe that
the proposed NSPS will not have a detrimental impact on the entry
of new plants into this subcategory.
Secondary Precious Metals
We have proposed that NSPS be equal to BAT, except for furnace
air pollution control, which we have proposed as zero discharge.
Except for furnace air pollution control, our review of the
industry indicates that no new demonstrated technologies exist
that improve on BAT technology. Zero discharge for furnace air
pollution control is based on dry scrubbing, which is demon-
strated at 11 out of 16 plants with furnace air pollution con-
trol. Cost for dry scrubbing air pollution control in a new
facility is no greater than the cost for wet scrubbing which was
the basis for BAT cost estimates. We believe that the proposed
NSPS are economically achievable, and that they are not a barrier
to entry of new plants into this subcategory.
Primary Rare Earth Metals
We have proposed that NSPS be equal to BAT. Our review of the
subcategory indicates that no new demonstrated technologies that
improve on BAT technology exist. We do not believe that new
485
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plants could achieve any flow reduction beyond the allowances
proposed for BAT. Because NSPS are equal to BAT, we believe that
the proposed NSPS will not have a detrimental impact on the entry
of new plants into this subcategory.
Secondary Tantalum
We have proposed that NSPS be equal to BAT. Our review of the
subcategory indicates that no new demonstrated technologies that
improve on BAT technology exist. We do not believe that new
plants could achieve any flow reduction beyond the allowances
proposed for BAT. Because NSPS are equal to BAT, we believe that
the proposed NSPS will not pose a barrier to the entry of new
plants into this subcategory.
Primary and Secondary Tin
We have proposed that NSPS be equal to BAT. Our review of the
subcategory indicates that no new demonstrated technologies that
improve on BAT technology exist. We do not believe that new
plants could achieve any flow reduction beyond the allowances
proposed for BAT. Because NSPS are equal to BAT, we believe that
the proposed NSPS will not pose a barrier to the entry of new
plants into this subcategory.
Primary and Secondary Titanium
We have proposed that NSPS be equal to BAT plus flow reduction
technology with additional flow reduction for four streams. Zero
discharge is proposed for chip crushing, sponge crushing and
screening, and scrap milling wet air pollution control wastewater
based on dry scrubbing. Zero discharge is also proposed for
chlorine liquefaction wet air pollution control based on
by-product recovery of scrubber liquor as hypochlorous acid.
Cost for dry scrubbing air pollution control in a new facility is
no greater than the cost for wet scrubbing which was the basis
for BAT cost estimates. Because NSPS are equal to BAT, we
believe that the proposed NSPS will not pose a barrier to the
entry of new plants into this subcategory.
Secondary Tungsten and Cobalt
We have proposed that NSPS be equal to BAT. Our review of the
subcategory indicates that no new demonstrated technologies that
improve on BAT technology exist. We do not believe that new
plants could achieve any flow reduction beyond the allowances
proposed for BAT. Because NSPS are equal to BAT, we believe that
the proposed NSPS will not pose a barrier to the entry of new
plants into this subcategory.
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Secondary Uranium
We have proposed chat NSPS be equal to BAT. Our review of the
subcategory indicates that no new demonstrated technologies that
improve on BAT technology exist. We do not believe that new
plants could achieve any flow reduction beyond the allowances
proposed for BAT. Because NSPS are equal to BAT, we believe that
the proposed NSPS will not pose a barrier to the entry of new
plants into this subcategory.
Primary Zirconium and Hafnium
We have proposed that NSPS be equal to BAT. Our review of the
subcategory indicates that no new demonstrated technologies that
improve on BAT technology exist. We do not believe that new
plants could achieve any flow reduction beyond the allowances
proposed for BAT. Because NSPS are equal to BAT, we believe that
the proposed NSPS will not pose a barrier to the entry of new
plants into this subcategory.
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SECTION XII
PRETREATMENT STANDARDS
Section 307(b) of the Clean Water 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, inter-
fere with, or are otherwise incompatible with the operation of
publicly owned treatment works (POTW). The Clean Water Act of
1977 adds a new dimension by requiring pretreatment for pollu-
tants, such as heavy metals, that limit POTW sludge management
alternatives, including the beneficial use of sludges on agricul-
tural lands. The legislative history of the 1977 Act indicates
that pretreatment standards are to be technology-based, analogous
to the best available technology for removal of toxic pollutants.
Section 307(c) of the Act requires EPA to promulgate pretreatment
standards for new sources (PSNS) at the same time that it promul-
gates NSPS. New indirect discharge facilities, like new direct
discharge facilities, have the opportunity to incorporate the
best available demonstrated technologies, including process
changes, in-plant controls, and end-of-pipe treatment technolo-
gies, and to use plant site selection to ensure adequate treat-
ment system installation.
General Pretreatment Regulations for Existing and New Sources of
Pollution were published in the Federal Register, Vol. 46, No.
18, Wednesday, January 28, 1981.These regulations describe the
Agency's overall policy for establishing and enforcing pretreat-
ment standards for new and existing users of a POTW and delin-
eates the responsibilities and deadlines applicable to each party
in this effort. In addition, 40 CFR Part 403, Section 403.5(b),
outlines prohibited discharges which apply to all users of a
POTW.
This section describes the treatment and control technology for
pretreatment of process wastewaters from existing sources and new
sources, and presents mass discharge limitations of regulated
pollutants for existing and new sources, based on the described
control technology. It also serves to summarize changes from
previous rulemakings in the nonferrous metals manufacturing
category.
REGULATORY APPROACH
There are 38 facilities, representing 27 percent of the nonfer-
rous metals manufacturing phase II category, who discharge waste-
waters to POTW. Pretreatment standards are established to ensure
removal of pollutants discharged by these facilities which may
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interfere with, pass through, or be incompatible with POTW opera-
tions. A determination of which pollutants may pass through or
be incompatible with POTW operations, and thus be subject to pre-
treatment standards, depends on the level of treatment used by
the POTW. In general, more pollutants will pass through or
interfere with a POTW using primary treatment (usually physical
separation by settling) than one which has installed secondary
treatment (settling plus biological treatment).
Many of the pollutants contained in nonferrous metals manufactur-
ing wastewaters are not biodegradable and are, therefore, not
effectively treated by such systems. Furthermore, these pollu-
tants have been known to pass through or interfere with the nor-
mal operations of these systems. Problems associated with the
uncontrolled release of pollutant parameters identified in non-
ferrous metals manufacturing process wastewaters to POTW were
discussed in Section VI.
The Agency based the selection of pretreatment standards for the
nonferrous metals manufacturing category on the minimization of
pass-through of toxic pollutants at POTW. For each subcategory,
the Agency compared removal rates for each toxic pollutant
limited by the pretreatment options to the removal rate for that
pollutant at well-operated POTW. The POTW removal rates were
determined through a study conducted by the Agency at over 40
POTW and a statistical analysis of the data. (See Fate of
Priority Pollutants in Publicly Owned Treatment Works, EPA
440/1-80-301, October, 1980; and Determining National Removal
Credits for Selected Pollutants for Publicly Owned Treatment
Works, EPA 440/82-008. September, 1982.)The POTW removal rates
are presented below:
Toxic Pollutant POTW Removal Rate
Antimony 0%
Arsenic 20%
Cadmium 38%
Chromium 65%
Copper 58%
Cyanide 52%
Lead 48%
Mercury 69%
Nickel 19%
Selenium 0%
Silver 66%
Zinc 65%
Hexachlorobenzene 12%
Ammonia 40%
Fluoride 0%
Total Regulated Metals 62%
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There were no data concerning POTW removals for beryllium, boron,
cobalt, germanium, indium, molybdenum, radium 226, thallium, tin,
titanium, and uranium, to compare with our estimates of in-plant
treatment. Removal of these pollutants is solubility related.
Since the removal of metal pollutants for which data are avail-
able is also solubility related, EPA believes that these pollu-
tants may pass through a POTW. It was assumed, therefore, that
these toxic metals pass through a POTW because they are soluble
in water and are not degradable. Pass-through data are not
available for benzo(a)pyrene; however, pass-through data for five
other polynuclear aromatic hydrocarbons do not exceed 83 percent.
This value was used for organics pass-through calculations.
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 direct dischargers complying with BAT effluent limita-
tions guidelines for that pollutant. (See generally, 46 FR
9415-16 (January 28, 1981).) For example, if the selected PSES
option removed 90 percent of the cadmium generated by the sub-
category, cadmium would be considered to pass through because a
well-operated POTW would be expected to remove 38 percent. Con-
versely, if the selected PSES option removed only 30 percent of
the cadmium generated by the subcategory, it would not be con-
sidered to pass through. In the latter case, cadmium would not
be selected for specific regulation because a well-operated POTW
would have a greater removal efficiency.
The analysis described above was performed for each subcategory
starting with the pollutants selected for regulation at BAT. The
conventional pollutant parameters (TSS, pH, and oil and grease)
were not considered for regulation under pretreatment standards.
The conventional pollutants are effectively controlled by POTW.
For those subcategories where ammonia was selected for specific
limitation, it will also be selected for limitation under pre-
treatment standards. Most POTW in the United States are not
designed for nitrification. Hence, aside from incidental
removal, most, if not all, of the ammonia introduced into POTW
will pass through into receiving waters without treatment.
An examination of the percent removal for the selected pretreat-
ment options indicated that the pretreatment option selected
removed at least 95 percent of the toxic pollutants generated in
the nonferrous metals manufacturing point source category. Con-
sequently, the toxics regulated for each subcategory under BAT
will also be regulated under pretreatment standards. Table XII-1
(page505 ) presents the pollutants selected for regulation for
pretreatment standards.
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MODIFICATIONS TO EXISTING PRETREATMENT STANDARDS
Metallurgical Acid Plants
As discussed in Section IX, the metallurgical acid plants sub-
category is being modified to include acid plants associated with
primary molybdenum roasters. This is based on the similarity
between discharge rates and effluent characteristics of waste-
waters from all metallurgical acid plants.
OPTION SELECTION
The treatment schemes considered for pretreatment standards for
new and existing sources are identical to those considered for
BAT. Each of the options considered builds upon the BPT tech-
nology basis of chemical precipitation and sedimentation.
Depending on the pollutants present in the subcategories raw
wastewaters, a combination of the treatment technologies listed
below were considered:
• Option A - End-of-pipe treatment consisting of chemical
precipitation and sedimentation, and preliminary treat-
ment, where necessary, consisting of oil skimming,
cyanide precipitation, and ammonia steam stripping.
This combination of technology reduces toxic metals and
cyanide, conventional, and nonconventional pollutants.
• Option B - Option B is equal to Option A preceded by
flow reduction of process wastewater through the use
of cooling towers for contact cooling water and holding
tanks for all other process wastewater subject to
recycle.
• Option C - Option C is equal to Option B plus end-of-
pipe polishing filtration for further reduction of
toxic metals and TSS.
• Option D - Option D is equal to Option C plus treatment
of isolated waste streams with activated carbon adsorp-
tion for removal of toxic organics and activated
alumina for reduction of fluorides and arsenic concen-
trations. This option was only considered for non-
ferrous metals manufacturing phase I.
• Option E - Option E consists of Option C plus activated
carbon adsorption applied to the total plant discharge
as a polishing step to reduce toxic organic concentra-
tions.
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• Option F - Option F consists of Option C plus reverse
osmosis treatment to attain complete recycle of all
process wastewater. This option was only considered
for nonferrous phase I.
The general approach taken by the Agency for pretreatment stan-
dards for this category is presented below. The mass-based stan-
dards for each subcategory may be found in Section II of this
document. The options selected for the category on which to base
pretreatment standards are discussed below.
Bauxite Refining
Pretreatment standards for existing sources are not being consid-
ered for the bauxite refining subcategory because there are no
existing indirect dischargers. We are not considering any modi-
fications to PSNS since it is unlikely that any new bauxite
sources will be constructed as indirect dischargers.
Primary Antimony
Pretreatment standards for existing sources were not proposed for
the primary antimony subcategory because there are no existing
indirect dischargers. We have proposed PSNS equivalent to NSPS
and BAT. The technology basis for proposed PSNS is identical to
NSPS and BAT. It was necessary to propose PSNS to prevent pass-
through of toxic metals. These metals are removed by a well-
operated POTW achieving secondary treatment at an average of 61
percent. PSNS technology removes these pollutants at an average
of 98 percent. We know of no economically feasible, demonstrated
technology that is better than BAT technology. No additional
flow reduction for new sources is feasible beyond the allowances
proposed for BAT. We believe that the proposed PSNS are not a
barrier to entry of new plants into this subcategory because they
do not include any additional costs compared to BAT.
Primary Beryllium
Pretreatment standards for existing sources were not proposed for
the primary beryllium subcategory since there are no indirect
dischargers. The technology basis for proposed PSNS is identical
to NSPS and BAT. It was necessary to propose PSNS to prevent
pass-through of beryllium, chromium, copper, and fluoride. These
toxic pollutants are removed by a well-operated POTW achieving
secondary treatment at an average of 41 percent while BAT tech-
nology removes approximately 93 percent. We know of no economi-
cally feasible, demonstrated technology that is better than BAT
technology. The PSNS flow allowances are based on minimization
of process wastewater wherever possible through the use of hold-
ing tanks for wet scrubbing wastewater. The discharges are based
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on 90 percent recycle of this waste stream (see Section IX -
Recycle of Wet Scrubber and Contact Cooling Water). No addi-
tional flow reduction for new sources is feasible. Because PSNS
does not include any additional costs compared to NSPS and BAT,
we do not believe it will prevent entry of new plants.
Primary Boron
Pretreatment standards for existing sources were not proposed for
the primary boron subcategory since there are no exisiting indi-
rect dischargers. We have proposed PSNS equal to NSPS (chemical
precipitation and sedimentation technology) for this subcategory.
It was necessary to propose PSNS to prevent pass-through of
boron, lead and nickel, which are the regulated pollutants in
this subcategory. These toxic pollutants are removed by a well-
operated POTW achieving secondary treatment at an average of 34
percent while NSPS level technology removes approximately 85
percent.
We believe that the proposed PSNS are achievable, and that they
are not a barrier to entry of new plants into this subcategory.
Primary Cesium and Rubidium
Pretreatment standards for existing sources were not proposed for
the primary cesium and rubidium subcategory because there are no
existing indirect dischargers. We have proposed PSNS equivalent
to NSPS. The technology basis for proposed PSNS is identical to
NSPS. It was necessary to propose this PSNS to prevent pass-
through of toxic metals. These metals are removed by a well-
operated POTW achieving secondary treatment at an average of 38
percent. PSNS technology removes these pollutants at an average
of 95 percent. We know of no economically feasible, demonstrated
technology that is better than NSPS technology.
The costs and specific removal data for this subcategory are not
presented here because the data on which they are based have been
claimed to be confidential. We believe that the proposed PSNS
are achievable, and that they are not a barrier to entry of new
plants into this subcategory.
Primary and Secondary Germanium and Gallium
Two levels of PSES have been proposed for this subcategory. The
first level, A, consists of chemical precipitation and sedimen-
tation. Level A applies to plants which only reduce germanium
dioxide to metal and practice zone refining and acid washings and
rinsing. These plants only have one waste stream - acid wash and
rinse water. The second level, B, consists of chemical precipi-
tation, sedimentation, and filtration. Level B applies to all
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other plants in the subcategory. The pollutants controlled at
PSES are the same as those controlled at BAT.
We have proposed PSES to prevent pass-through of arsenic, lead,
zinc, fluoride, and germanium. These pollutants are removed by a
well-operated POTW achieving secondary treatment at an average of
33 percent while BAT Level A technology removes approximately 87
percent and Level B technology approximately 99 percent.
Implementation of the proposed Level A PSES limitations would
remove annually an estimated 20 kg of toxic metals, 818 kg of
germanium, and 376 kg of fluoride from the raw waste load.
There are no existing Level B plants in the subcategory which are
indirect dischargers.
The costs and specific removal data for this subcategory are not
presented here because the data on which they are based have been
claimed to be confidential. The proposed PSES will not result in
adverse economic impacts.
We have proposed PSNS equivalent to PSES, NSPS and BAT. The
technology basis for proposed PSNS is identical to NSPS, PSES,
and BAT. The same pollutants pass through as at PSES, for the
same reasons. We believe that the proposed PSNS are not a
barrier to entry of new plants into this subcategory because they
do not include any additional costs compared to BAT.
Secondary Indium
We are proposing PSES limitations for this subcategory based on
chemical precipitation and sedimentation technology. The pollu-
tants specifically regulated under PSES are cadmium, lead, zinc,
and indium. The toxic pollutants chromium, nickel, selenium,
silver, and thallium were also considered for regulation because
they are present at treatable concentrations in the raw waste-
waters from this subcategory. These pollutants were not selected
for specific regulation because they will be effectively con-
trolled when the regulated toxic metals are treated to the levels
achievable by the model technology. It is necessary to propose
PSES to prevent pass-through of cadmium, lead, and zinc. These
toxic pollutants are removed by a well-operated POTW achieving
secondary treatment at an average of 38 percent while this BAT
level technology removes approximately 90 percent.
Implementation of the proposed PSES limitations would remove
annually an estimated 586 kg of toxic metals and 288 kg of
indium.
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We have proposed PSNS equal to NSPS. The technology basis for
proposed PSNS is identical to NSPS. The same pollutants pass
through as at PSES, for the same reasons.
We believe that the proposed PSNS are achievable, and that they
are not a barrier to entry of new plants into this subcategory.
Secondary Mercury
Pretreatment standards for existing sources were not proposed for
the secondary mercury subcategory since there are no existing
indirect dischargers.
We have proposed PSNS equivalent to NSPS for this subcategory.
It was necessary to propose PSNS to prevent pass-through of lead
and mercury. These 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.
We believe that the proposed PSNS are achievable, and that they
are not a barrier to entry of new plants into this subcategory.
Primary Molybdenum and Rhenium
Pretreatment standards for existing sources were not proposed for
the primary molybdenum and rhenium subcategory since there are no
existing indirect dischargers.
We have proposed PSNS equal to BAT for this subcategory. It was
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 believe that the proposed PSNS are achievable, and that they
are not a barrier to entry of new plants into this subcategory.
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
well-operated POTW achieving secondary treatment at an average of
42 percent while BAT level technology removes approximately 83
percent.
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We believe that the proposed PSNS are achievable, and that they
are not a barrier to entry of new plants into this subcategory
because they do not include any additional costs compared to BAT.
Secondary Molybdenum and Vanadium
Pretreatment standards for existing sources were not proposed for
the secondary molybdenum and vanadium subcategory since there are
no existing indirect dischargers.
We have proposed PSNS equal to BAT and NSPS for this subcategory.
It was necessary to propose PSNS to prevent pass-through of anti-
mony, lead, nickel, molybdenum, and ammonia. These toxic pollu-
tants are removed by a well-operated POTW achieving secondary
treatment at an average of 23 percent, while the NSPS and BAT
level technology removes approximately 98 percent.
The technology basis for PSNS is ammonia steam stripping,
chemical precipitation and sedimentation, and filtration. The
achievable concentration for ammonia steam stripping is based on
iron and steel manufacturing category data, as explained in the
discussion of BPT and BAT for this subcategory.
We believe that the proposed PSNS are achievable, and that they
are not a barrier to entry of new plants into this subcategory
because they do not include any additional costs compared to BAT.
Primary Nickel and Cobalt
Pretreatment standards for existing sources were not proposed for
the primary nickel and cobalt subcategory since there are no
existing indirect dischargers.
We have proposed PSNS equal to BAT and NSPS for this subcategory.
It was necessary to propose PSNS to prevent pass-through of cop-
per, nickel, cobalt, and ammonia. These toxic pollutants are
removed by a well-operated POTW at an average of 26 percent,
while BAT technology removes approximately 58 percent.
The technology basis for PSNS is ammonia steam stripping,
chemical precipitation and sedimentation, and filtration. The
achievable concentration for ammonia steam stripping is based on
iron and steel manufacturing category data, as explained in the
discussion of BPT and BAT for this subcategory.
We believe that the proposed PSNS are achievable, and that they
are not a barrier to entry of new plants into this subcategory
because they do not include any additional costs compared to BAT.
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Secondary Nickel
We are proposing PSES for this subcategory based on chemical
precipitation, sedimentation, and filtration (filtration is
proposed for acid reclaim leaching filtrate and acid reclaim
leaching filter backwash, but not for slag reclaim tailings).
The pollutants specifically regulated under PSES are chromium,
copper, and nickel. The toxic pollutants arsenic and zinc were
also considered for regulation because they are present at treat-
able concentrations in the raw wastewaters from this subcategory.
These pollutants were not selected for specific regulation
because they will be effectively controlled when the regulated
toxic metals are treated to the levels achievable by the model
technology. We are proposing PSES to prevent pass-through of
chromium, copper, and nickel. These toxic pollutants are removed
by a well-operated POTW at an average of 32 percent while PSES
technology removes approximately 84 percent.
Implementation of the proposed PSES limitations would remove
annually an estimated 1,113 kg of toxic metals from the raw waste
loads. We estimate a capital cost of $287,000 and an annualized
cost of $120,000 to achieve the proposed PSES. The proposed PSES
will not result in adverse economic impacts.
We have proposed PSNS equivalent to NSPS and PSES. The same pol-
lutants pass through at PSNS as at PSES, for the same reasons.
We know of no economically feasible, demonstrated technology that
is better than PSES technology. The PSES flow allowances are
based on minimization of process wastewater wherever possible.
We believe that the proposed PSNS are achievable, and that they
are not a barrier to entry of new plants into this subcategory.
Primary Precious Metals and Mercury
Pretreatment standards for existing sources were not proposed for
the primary precious metals and mercury subcategory because there
are no existing indirect dischargers.
We have proposed PSNS equal to BAT and NSPS for this subcategory.
It was necessary to propose PSNS to prevent pass-through of
arsenic, lead, mercury, silver, and zinc. These toxic pollutants
are removed by a well-operated POTW at an average of 62 percent,
while the NSPS and BAT technology removes approximately 93
percent.
The technology basis for PSNS is oil skimming, chemical precipi-
tation and sedimentation, wastewater flow reduction and filtra-
tion. Flow reduction is based on 90 percent recycle of scrubber
effluent that is the flow basis of BAT.
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We believe that the proposed PSNS are achievable, and that they
are not a barrier to entry of new plants into this subcategory
because they do not include any additional costs compared to BAT.
Secondary Precious Metals
We have proposed PSES equal to BAT for this subcategory. It is
necessary to propose PSES to prevent pass-through of copper,
cyanide, zinc, and ammonia. These toxic pollutants are removed
by a well-operated POTW achieving secondary treatment at an aver-
age of 32 percent while BAT level technology removes approxi-
mately 99 percent. The technology basis for PSES is chemical
precipitation and sedimentation, ammonia steam stripping, cyanide
precipitation, wastewater flow reduction, and filtration. The
achievable concentration for ammonia steam stripping is based on
iron and steel manufacturing category data, as explained in the
discussion of BPT and BAT for this subcategory. Flow reduction
is based on the same recycle of scrubber effluent that is the
flow basis of BAT. Recycle is practiced by 21 of the 29 existing
plants in the subcategory.
Implementation of the proposed PSES limitations would remove
annually an estimated 98,550 kg of toxic pollutants including 840
kg of cyanide, and an estimated 9,240 kg of ammonia from the raw
waste load. Capital cost for achieving proposed PSES is
$1,419,000 and annualized cost of $984,000. The proposed PSES
will not result in adverse economic impacts.
An intermediate option considered for PSES is BAT equivalent
technology without filters. This option removes an estimated
65,319 kg of toxic pollutants and 9,240 kg of ammonia. We esti-
mate the capital cost of this technology is $1,325,000, and
annual cost $928,000.
We have proposed PSNS equivalent to NSPS. The technology basis
for proposed PSNS is identical to NSPS. This is equivalent to
PSES and BAT, with additional flow reduction based on dry air
pollution control on furnace emissions. The same pollutants pass
through at PSNS as at PSES, for the same reasons. We know of no
economically feasible, demonstrated technology that is better
than NSPS technology. The NSPS flow allowances are based on
minimization of process wastewater wherever possible through the
use of holding tanks to recycle wet scrubbing wastewater and the
use of dry scrubbing to control furnace emissions. The dis-
charges are based on recycle of these waste streams.
There are no additional costs associated with the installation of
dry scrubbers instead of wet scrubbers which were used for esti-
mating cost of BAT. We believe that the proposed PSNS are
achievable, and that they are not a barrier to entry of new
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plants into this subcategory because they do not include any
additional costs compared to BAT and PSES.
Primary Rare Earth Metals
We have proposed PSES equal to BAT for this subcategory. It is
necessary to propose PSES to prevent pass-through of hexachloro-
benzene, chromium, lead, and nickel. These toxic pollutants are
removed by a well-operated POTW achieving secondary treatment at
an average of 28 percent while BAT technology removes approxi-
mately 74 percent. The technology basis for PSES is chemical
precipitation and sedimentation, wastewater flow reduction,
filtration, and activated carbon. Flow reduction is based on 90
percent recycle of scrubber effluent that is the flow basis of
BAT. Filtration is an effluent polishing step that removes
additional pollutants.
Implementation of the proposed PSES limitations would remove
annually an estimated 10.9 kg of toxic pollutants from the raw
waste load. The costs and specific removal data for this sub-
category are not presented here because the data on which they
are based have been claimed to be confidential. The proposed
PSES will not result in adverse economic impacts.
An intermediate option considered for PSES is BAT equivalent
technology without activated carbon adsorption. This option
removes an estimated 1.9 kg of toxic pollutants.
We have proposed PSNS equivalent to PSES, NSPS and BAT. The
technology basis for proposed PSNS is identical to NSPS, PSES,
and BAT. The same pollutants pass through at PSNS as at PSES,
for the same reasons. We know of no economically feasible,
demonstrated technology that is better than PSES technology. The
PSNS flow allowances are equal to the BAT, NSPS, and PSES flow
allowances.
We believe that the proposed PSNS are achievable, and that they
are not a barrier to entry of new plants into this subcategory
because they do not include any additional costs compared to BAT
and PSES.
Secondary Tantalum
Pretreatment standards for existing sources were not proposed for
the secondary tantalum subcategory since there are no existing
indirect dischargers.
We have proposed PSNS equal to NSPS and BAT. It was necessary to
propose PSNS to prevent pass-through of copper, lead, nickel, and
zinc. These toxic pollutants are removed by a well-operated POTW
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achieving secondary treatment at an average of 48 percent, while
BAT level technology removes approximately 99 percent.
We believe that the proposed PSNS are achievable, and that they
are not a barrier to entry of new plants into this subcategory
because they do not include any additional costs compared to BAT.
Primary and Secondary Tin
We have proposed PSES equal to BAT for this subcategory. It is
necessary to propose PSES to prevent pass-through of antimony,
cyanide, lead, nickel, tin, ammonia, and fluoride. The four
toxic pollutants and fluoride are removed by a well-operated POTW
achieving secondary treatment at an average of 17 percent while
BAT technology removes approximately 97 percent. The technology
basis for PSES is chemical precipitation, sedimentation, and
filtration with preliminary treatment consisting of cyanide
precipitation and ammonia steam stripping.
Implementation of the proposed PSES limitations would remove
annually an estimated 152 kg of toxic metals, 6,282 kg of tin, 32
kg of cyanide, and 25,105 kg fluoride over estimated raw waste
load. Capital cost for achieving proposed PSES is $341,700, and
annual cost of $119,900. The proposed PSES will not result in
adverse economic impacts.
We have proposed PSNS equivalent to PSES, NSPS, and BAT. The
technology basis for proposed PSNS is identical to NSPS, PSES,
and BAT. The same pollutants pass through at PSNS as at PSES,
for the same reasons. We know of no economically feasible,
demonstrated technology that is better than PSES technology. The
PSNS flow allowances are identical to the flow allowances for
BAT, NSPS, and PSES.
There would be no additional cost for PSNS above the costs esti-
mated for BAT. We believe that the proposed PSNS are achievable,
and that they are not a barrier to entry of new plants into this
subcategory because they do not include any additional costs com-
pared to BAT and PSES.
Primary and Secondary Titanium
We have proposed PSES equal to BAT for this subcategory. It is
necessary to propose PSES to prevent pass-through of chromium,
lead, nickel, thallium, titanium, and fluoride. The four toxic
pollutants are removed by a well-operated POTW achieving second-
ary treatment at an average of 14 percent while BAT Level A
technology removes approximately 53 percent and Level B technol-
ogy removes approximately 76 percent. Implementation of the
proposed PSES limitations would remove annually an estimated 1.7
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kg of toxic pollutants, and 147 kg of titanium from the raw waste
load.
The costs and specific removal data for this subcategory are not
presented here because the data on which they are based have been
claimed to be confidential. The proposed PSES will not result in
adverse economic impacts.
We have proposed Level A and Level B PSNS equivalent to NSPS.
The technology basis for proposed PSNS is identical to NSPS. The
same pollutants are regulated at PSNS as at PSES and they pass
through at PSNS as at PSES, for the same reasons. The PSNS and
NSPS flow allowances are based on minimization of process waste-
water wherever possible through the use of cooling towers to
recycle contact cooling water and holding tanks for wet scrubbing
wastewater. The discharge allowance for pollutants is the same
at PSNS and NSPS. The discharges are based on 90 percent recycle
of these waste streams (see Section IX - recycle of wet scrubber
and contact cooling water). As in NSPS, flow reduction beyond
BAT is proposed chip crushing, sponge crushing and screening, and
scrap milling wet air pollution control wastewater based on dry
scrubbing. Also, zero discharge is proposed for chlorine lique-
faction wet air pollution control wastewater based on by-product
recovery.
We believe that the proposed PSNS are achievable, and that they
are not a barrier to entry of new plants into this subcategory
because they do not include any additional costs compared to BAT
and PSES.
Secondary Tungsten and Cobalt
Pretreatment standards for existing sources were not proposed for
the secondary tungsten and cobalt subcategory since there are no
existing indirect dischargers.
We have proposed PSNS equal to BAT and NSPS for this subcategory.
It was necessary to propose PSNS to prevent pass-through of cop-
per, nickel, cobalt, and ammonia. These toxic pollutants are
removed by a well-operated POTW achieving secondary treatment at
an average of 26 percent, while the NSPS and BAT level technology
removes approximately 97 percent.
The technology basis for PSNS is ammonia steam stripping, oil
skimming, chemical precipitation and sedimentation, wastewater
flow reduction and filtration. The achievable concentration for
ammonia steam stripping is based on iron and steel manufacturing
category data, as explained in the discussion of BPT and BAT for
this subcategory. Flow reduction is based on 90 percent recycle
of scrubber effluent that is the flow basis of BAT.
502
-------
We believe that the proposed PSNS are achievable, and that they
are not a barrier to entry of new plants into this subcategory
because they do not include any additional costs compared to BAT.
Secondary Uranium
Pretreatment standards for existing sources were not proposed for
the secondary uranium subcategory since there are no existing
indirect dischargers.
We have proposed PSNS equal to BAT and NSPS for this subcategory.
It was necessary to propose PSNS to prevent pass-through of
chromium, copper, nickel, ammonia, uranium, and fluoride. These
toxic pollutants are removed by a well-operated POTW achieving
secondary treatment at an average of 40 percent, while the NSPS
and BAT level technology removes approximately 88 percent.
The technology basis for PSNS is chemical precipitation, sedimen-
tation, and ammonia steam stripping, followed by filtration.
We believe that the proposed PSNS are achievable, and that they
are not a barrier to entry of new plants into this subcategory
because they do not include any additional costs compared to BAT.
Primary Zirconium and Hafnium
Two levels of PSES equal to BAT have been proposed for this sub-
category. It is necessary to propose PSES to prevent pass-
through of chromium, cyanide, lead, nickel, ammonia, and radium
(226). These toxic pollutants are removed by a well-operated
POTW at an average of 30 percent, while BAT Level A technology
removes approximately 40 percent and Level B technology removes
approximately 80 percent.
Level A PSES is for plants which only produce zirconium or
zirconium/nickel alloys by reduction of zirconium dioxide with
magnesium or hydrogen. The technology basis for Level A PSES is
preliminary treatment consisting of ammonia steam stripping and
cyanide precipitation where necessary, barium chloride co-precip-
itation, chemical precipitation, sedimentation, and flow reduc-
tion. Level B PSES is for all other plants in the subcategory.
Level B PSES is based on preliminary treatment consisting of
ammonia steam stripping and cyanide precipitation where neces-
sary, barium chloride co-precipitation, chemical precipitation,
sedimentation, wastewater flow reduction, and filtration. Flow
reduction is based on 90 percent recycle of scrubber effluent.
Implementation of the proposed PSES Level A limitations would
remove annually an estimated 0.5 kg of toxic pollutants from the
raw waste load. There is no capital cost for achieving the
proposed Level A PSES.
503
-------
There are currently no Level B plants in this subcategory which
are indirect dischargers. If nondischarging plants in this sub-
category were to become Level B indirect dischargers, compliance
with the proposed Level B PSES would remove 10.6 kg of toxic
metals, 7.3 kg of cyanide, and 15 kg of ammonia annually.
The costs and specific removal data for this subcategory are not
presented here because the data on which they are based have been
claimed to be confidential. The proposed PSES will not result in
adverse economic impacts.
We are proposing PSNS equivalent to PSES, NSPS, and BAT. The
technology basis for proposed PSNS is identical to NSPS. The
same pollutants pass through as at PSES for the same reasons. We
know of no economically feasible, demonstrated technology that is
better than PSES technology.
We believe that the proposed PSNS are achievable, and that they
are not a barrier to entry of new plants into this subcategory
because they do not include any additional costs compared to BAT
and PSES.
504
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Table XII-1
POLLUTANTS SELECTED FOR REGULATION FOR PRETREATMENT
STANDARDS BY SUBCATEGORY
Subcategory
Pollutant Parameters
Bauxite Refining
(As discussed earlier, the Agency
is considering effluent limitations
for discharges from bauxite red mud
impoundments. To assist the public
in providing comment on this issue,
we are providing information in this
table on the bauxite subcategory)
Primary Antimony
Primary Beryllium
Primary Boron
Primary Cesium & Rubidium
Primary and Secondary
Germanium and Gallium
Secondary Indium
Secondary Mercury
24. [2-chlorophenol]
65. [phenol]
[phenols (4-AAP)]
114.
115.
122.
123.
117.
119.
120.
antimony
arsenic
lead
mercury .
beryllium
chromium
copper
fluoride
122. lead
124. nickel
boron
122. lead
127. thallium
128. zinc
115. arsenic
122. lead
128. zinc
germanium
fluoride
118. cadmium
122. lead
128. zinc
ind ium
122. lead
123. mercury
505
-------
Table XII-1 (Continued)
POLLUTANTS SELECTED FOR REGULATION FOR PRETREATMENT
STANDARDS BY SUBCATEGORY
Subcategory
Pollutant Parameters
Primary Molybdenum
and Rhenium
Secondary Molybdenum
and Vanadium
Primary Nickel and Cobalt
Secondary Nickel
Primary Precious Metals
and Mercury
Secondary Precious Metals
Primary Rare Earth Metals
115. arsenic
122. lead
124. nickel
125. selenium
molybdenum
ammonia (as N)
114. antimony
122. lead
124. nickel
molybdenum
ammonia (as N)
120. copper
124. nickel
cobalt
ammonia (as N)
11 9. chromium
120. copper
124. nickel
115. arsenic
122. lead
123. mercury
126. silver
128. zinc
120. copper
121. cyanide
128. zinc
ammonia (as N)
9. hexachlorobenzene
119. chromium (total)
122. lead
124. nickel
506
-------
Table XI1-1 (Continued)
POLLUTANTS SELECTED FOR REGULATION FOR PRETREATMENT
STANDARDS BY SUBCATEGORY
Subcategory
Pollutant Parameters
Secondary Tantalum
Primary and Secondary Tin
Primary and Secondary
Titanium
Secondary Tungsten
and Cobalt
Secondary Uranium
Primary Zirconium
and Hafnium
120. copper
122. lead
124. nickel
128. zinc
114. antimony
121. cyanide
122. lead
124. nickel
tin
ammonia (as N)
fluoride
119. chromium (total)
122. lead
124. nickel
127. thallium
titanium
fluoride
120. copper
124. nickel
cobalt
ammonia (as N)
119. chromium (total)
120. copper
124. nickel
uranium
ammonia (as N)
fluoride
119. chromium (total)
121. cyanide (total)
122. lead
124. nickel
radium 226
ammonia (as N)
507
-------
SECTION XIII
BEST CONVENTIONAL POLLUTANT CONTROL TECHNOLOGY
EPA is not proposing best conventional pollutant control technol-
ogy (BCT) for the nonferrous metals manufacturing (phase II)
category at this time.
509
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SECTION XIV
ACKNOWLEDGEMENTS
The initial draft of this document was prepared by Sverdrup and
Parcel and Associates under Contract No. 68-01-4409. The docu-
ment has been checked and revised at the specific direction of
EPA personnel by Radian Corporation under Contract No.
68-01-6529.
Two sampling programs were conducted. The first program was
conducted under the leadership of Mr. Garry Aronberg of Sverdrup
and Parcel; the second program was conducted under the leadership
of Mr. Mark Hereth of Radian Corporation. Preparation and
writing of the initial drafts of this document were accomplished
by Mr. Donald Washington, Project Manager, Mr. Garry Aronberg,
Ms. Claudia O'Leary, Mr. Antony Tawa, Mr. Charles Amelotti, and
Mr. Jeff Carlton of Sverdrup and Parcel. Mr. James Sherman,
Program Manager, Mr. Mark Hereth, Project Director, Mr. John
Vidumsky, Mr. Richard Weisman, Mr. Andrew Oven, Ms. Diane
Neuhaus, Mr. Marc Papai, and Ms. Jill Mitchell have contributed
in specific assignments in the final preparation of this
document.
The project was conducted by the Environmental Protection Agency,
Metals and Machinery Branch, Mr. Ernst P. Hall, Chief. The tech-
nical project officer is Mr. James Berlow; the previous technical
project officer was Ms. Patricia Williams. The project's legal
advisor is Mr. Ephraim King, who contributed to this project.
The economic project officer is Mr. Mark Kohorst. Contributions
from the Monitoring and Data Support Division came from
Mr. Richard Healy.
The individual companies whose plants were sampled and who sub-
mitted detailed information in response to questionnaires are
gratefully appreciated.
Acknowledgement and appreciation is also given to the secretarial
staff of Radian Corporation (Ms. Nancy Reid, Ms. Sandra Moore,
Ms. Daphne Phillips, and Ms. Elaine Robertson).
511
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SECTION XV
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513
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514
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515
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516
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518
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519
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520
-------
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Technology, Denver, September, 1976, Volume 2, pp. 808-16 (1976)
cited by Coleman, R. T., et. al., Draft Copy Treatment Methods
for Acidic Wastewater Containing Potentially Toxic Metal
Compounds, Report by Radian Corporation, Austin, TX, submitted to
USEPA Industrial Environmental Research Laboratory, Cincinnati,
OH (1978).
95. LaPerle, R. L., "Removal of Metals from Photographic
Effluent by Sodium Sulfide Precipitation," Journal Appl. Photogr.
Eng. 2, 134, (1976) cited by Coleman, R. T., et. al., Draft Copy
Treatment Methods for Acidic Wastewater Containing Potentially
Toxic Metal Compounds, Report by Radian Corporation, Austin, TX,
submitted to USEPA Industrial Environmental Research Laboratory,
Cincinnati, OH (1978).
96. Scott, M. (Senior Marketing Specialist, Permutit Company),
Private communications with R. Klausmeier (November, 1977) cited
by Coleman, R. T., et. al., Draft Copy Treatment Methods for
Acidic Wastewater Containing Potentially Toxic Metal Compounds,
Report by Radian Corporation, Austin, TX, submitted to USEPA
Industrial Environmental Research Laboratory, Cincinnati, OH
(1978).
521
-------
97. Development Document for Interim Final and Proposed Effluent
Limitations Guidelines and New Source Performance Standards for
the Ore Mining and Dressing Industry, EPA-440/1-75-061, Environ-
mental Protection Agency (1975) cited by Coleman, R. T., et. al.,
Draft Copy Treatment Methods for Acidic Wastewater Containing
Potentially Toxic Metal Compounds, Report by Radian Corporation,
Austin, TX, submitted to USEPA Industrial Environmental Research
Laboratory, Cincinnati, OH (1978).
98. Coleman, R. T. and Malish, D. A., Trip Report to Paul Bergoe
and Son, Boliden Aktiebolag and Outokumpu as part of EPA Contract
68-02-2608, Radian Corporation (November, 1977) cited by Coleman,
R. T., et. al., Draft Copy Treatment Methods for Acidic Waste-
water Containing Potentially Toxic Metal Compounds, Report by
Radian Corporation, Austin, TX, submitted to USEPA Industrial
Environmental Research Laboratory, Cincinnati, OH (1978).
99. Maltson, M. E., "Membrane Desalting Gets Big Push," Water
and Wastes Engineering (April, 1975), p. 35.
100. Cruver, J. E., "Reverse Osmosis for Water Reuse," Gulf
Environmental System (June, 1973).
101. "Water Renovation of Municipal Effluents by Reverse
Osmosis," Gulf Oil Corporation, San Diego (February, 1972).
102. Spatz, D. D., "Methods of Water Purification," Presented to
the American Association of Nephrology Nurses and Technicians at
the ASAIO AANNT Joint Conference, Seattle, Washington (April,
1972).
103. Donnelly, R. G., Goldsmith, R. L., McNulty, K. J., Grant,
D. C., and Tan, M., Treatment of Electroplating Wastes by Reverse
Osmosis, EPA-600/2-76-261, Environmental Protection Agency
(September, 1976).
104. Rook, J. J., "Haloforms in Drinking Water," Journal
American Water Works Association, 68:3:168 (1976).
105. Rook, J. J., "Formation of Haloforms During Chlorination of
Natural Waters," Journal Water Treatment Examination, 23:234
(1974).
106. Trussell, R. R. and Umphres, M. D., "The Formation of
Trihalomethanes," Journal American Water Works Association
70:11 :604 (1978).
107. Nebel, C., Goltschlintg, R. D., Holmes, J. L., and Unangst,
P. C., "Ozone Oxidation of Phenolic Effluents," Proceedings of
the 31st Industrial Waste Conference, Purdue University (1976),
pp. 940-951.
522
-------
108. Rosen, H. M., "Wastewater Ozonation: a Process Whose Time
Has Come," Civil Engineering, 47, 11, 65 (1976).
109. Hardisty, D. M. and Rosen, H. M., "Industrial Wastewater
Ozonation," Proceedings of the 32nd Industrial Waste Conference,
Purdue University (1976), pp. 940-951.
110. Traces of Heavy Metals in Water Removal Processes and
Monitoring, EPA-902/9-74-D01, Environmental Protection Agency
(November, 1973).
111. Symons, J. M., "Interim Treatment Guide for Controlling
Organic Contaminants in Drinking Water Using Granular Activated
Carbon," Water Supply Research Division, Municipal Environmental
Research Laboratory, Office of Research and Development, USEPA,
Cincinnati, OH (January, 1978).
112. McCreary, J. J. and V. L. Snoeyink, "Granular Activated
Carbon in Water Treatment," Journal American Water Works
Association, 69, 8, 437 (1977).
113. Grieves, C. G. and Stevenson, M. K., "Activated Carbon
Improves Effluents," Industrial Wastes (July/August, 1977), pp.
30-35.
114. Beebe, R. L. and Stevens, J. I., "Activated Carbon System
for Wastewater Renovation," Water and Wastes Engineering
(January, 1967), pp. 43-45.
115. Gulp, G. L. and Shuckrow, A. J., "What lies ahead for PAC,"
Water and Wastes Engineering (February, 1977), pp. 67-72, 74.
116. Savinelli, E. A. and Black, A. P., "Defluoridation of Water
With Activated Alumina," Journal American Water Works
Association, 50, 1, 33 (1958).
117. Paulson, E. G., "Reducing Fluoride in Industrial Waste-
water," Chemical Engineering, Deskbook Issue (October 17, 1977).
118. Bishop, P. L. and Sansovey, G., "Fluoride Removal from
Drinking Water by Fluidized Activated Alumina Adsorption,"
Journal American Water Works Association, 70,10,554 (1978).
119. Harmon, J. A. and Kalichman, S. G., "Defluoridation of
Drinking Water in Southern California," Journal American Water
Works Association, 57:2:245 (1965).
120. Maier, F. J., "Partial Defluoridation of Water," Public
Works, 91:90 (1960).
523
-------
121. Bellack, E., "Arsenic Removal from Potable Water," Journal
American Water Works Association, 63, 7 (1971).
122. Gupta, S. K. and Chen, K. Y., "Arsenic Removal by Adsorp-
tion," Journal Water Pollution Control Association (March, 1978),
pp. 493-506.
123. Johnson, D. E. L., "Reverse Osmosis Recycling System for
Government Arsenal," American Metal Market (July 31, 1973) cited
in Draft Development Document for Effluent Limitations Guidelines
and New Source Performance Standards for the Miscellaneous
Nonferrous Metals Segment, EPA-440/1-76-067, Environmental
Protection Agency (March, 1977).
124. Nachod, F. C. and Schubert, J., Ion Exchange Technology,
Academic Press, Inc. (1956).
125. Volkert, David, and Associates, "Monograph on the Effec-
tiveness and Cost of Water Treatment Processes for the Removal of
Specific Contaminants," EPA 68-01-1833, Office of Air and Water
(1974) cited by Contaminants Associated with Direct and Indirect
Reuse of Municipal Wastewater, EPA-600/1-78-019 (March, 1978).
126. Clark, J. W., Viessman, W., Jr., and Hammer, M., Water
Supply and Pollution Control, (3rd ed.) IEP, New York (1977).
127. AWARE (Associated Water and Air Resources Engineers, Inc.),
Analysis of National Industrial Water Pollution Control Costs,"
(May 21, 1973).
128. AWARE, "Alternatives for Managing Wastewater in the Three
Rivers Watershed Area," (October, 1972).
129. Bechtel, "A Guide to the Selection of Cost-Effective
Wastewater Treatment Systems," EPA 430/9-75-002 (July, 1975).
130. Smith, R., "Cost of Conventional and Advanced Treatment of
Wastewater," Journal Water Pollution Control Federation, 40, 9,
1546 (1968).
131. Icarus, "Capital and Operating Costs of Pollution Control
Equipment Modules," Vols. I and II, EPA-R5-73-023a & b (July,
1973) .
132. Monti, R. P. and Silberman, P. T., "Wastewater System
Alternatives: What Are They . . . and What Cost," Water and
Waste Engineering (May, 1974), p. 40.
133. Process Design Manual for Removal of Suspended Solids,
EPA-625/175-003a (January, 1975).
524
-------
134. Process Design Manual for Carbon Adsorption, EPA
625/1-71-002a (October, 1973).
135. Grits, G. J., "Economic Factors in Water Treatment,"
Industrial Water Engineering (November, 1971), p. 22.
136. Barnard, J. L. and Eckenfelder, W. W., Jr., "Treatment Cost
Relationships for Industrial Waste Treatment, Environmental and
Water Resources Engineering, Vanderbilt University (1971).
137. Grits, G. J. and Glover, G. G., "Cooling Slowdown in Cool-
ing Towers," Water and Wastes Engineering (April, 1975), p. 45.
138. Kremen, S. S., "The True Cost of Reverse Osmosis,"
Industrial Wastes (November/December, 1973), p. 24.
139. Cruver, J. E. and Sleigh, J. H. , "Reverse Osmosis - The
Emerging Answer to Seawater Desalination," Industrial Water
Engineering (June/July, 1976), p. 9.
140. Doud, D. H., "Field Experience with Five Reverse Osmosis
Plants," Water and Sewage Works (June, 1976), p. 96.
141. Lacey, R. E. and Loed, S., (eds.), "Industrial Processing
with Membranes," in The Cost of Reverse Osmosis, John Wiley and
Sons (1972).
142. Disposal of Brines Produced in Renovation of Industrial
Wastewater, FWQA Contract #14-12-492 (May, 1970).
143. Process Design Manual for Sludge Treatment and Disposal,
EPA 625/1-74-006 (October, 1974).
144. Black & Veatch, "Estimating Cost and Manpower Requirements
for Conventional Wastewater Treatment Facilities," EPA Contract
#14-12-462 (October, 1971).
145. Osmonics, Inc., "Reverse Osmosis and Ultrafiltration
Systems Bulletin No. G7606," (1978).
146. Buckley, J. D., "Reverse Osmosis; Moving from Theory to
Practice," From Fluid Systems Div., UOP, Inc. (Reprint from
Consulting Engineer), 45, 5, 55 (1975).
147. Process Design Manual for Nitrogen Control, EPA-Technology
Transfer (October, 1975).
148. Rizzo and Shepherd, "Treating Industrial Wastewater with
Activated Carbon," Chemical Engineering (January 3, 1977).
525
-------
149. Richardson, "1978-79 Process Equipment," Vol. 4 of
Richardson Rapid System."
150. Thiansky, D. P., "Historical Development of Water Pollution
Control Cost Functions," Journal Water Pollution Control
Federation, 46, 5, 813 (1974).
151. Zimmerman, 0. T., "Wastewater Treatment," Cost Engineering
(October, 1971) , p. 11.
152. Watson, I. C., (Control Research, Inc.) "Manual for
Calculation of Conventional Water Treatment Costs," Office of
Saline Water (March, 1972).
153. Gulp, R. L., Wesner, G. M., Gulp, G. L., Handbook of
Advanced Wastewater Treatment, McGraw-Hill (1978).
154. Dynatech R/D Company, A Survey of Alternate Methods for
Cooling Condenser Discharge Water Large-Scale Heat Rejection
Equipment, EPA Project No. 16130 DHS (July, 1969).
155. Development Document for Steam Electric Power Generating,
EPA 440/1-73/029 (March, 1974).
156. "Cooling Towers - Special Report," Industrial Water
Engineering (May, 1970).
157. AFL Industries, Inc., "Product Bulletin #12-05.B1 (Shelter
Uses)," Chicago, IL (December 29, 1977).
158. Fisher Scientific Co., Catalog 77 (1977).
159. Isco, Inc., Purchase Order Form, Wastewater Samplers
(1977).
160. Dames & Moore, Construction Cost for Municipal Wastewater
Treatment Plants: 1973-1977, EPA-430/9-77-013, MCD-37 (January,
1978).
161. Metcalf & Eddy, Inc., Wastewater Engineering: Collection,
Treatment, Disposal, McGraw-Hill, New York (1972).
162. Obert, E. F. and Young, R. L., Elements of Thermodynamics
and Heat Transfer, McGraw-Hill (1962), p. 270.
163. Paulson, E. G., "How to Get Rid of Toxic Organics,"
Chemical Engineering, Deskbook Issue (October 17, 1977), pp.
21-27.
164. CH2-M-Hill, "Estimating Staffing for Municipal Wastewater
Treatment Facilities," EPA #68-01-0328 (March, 1973).
526
-------
165. "EPA Indexes Reflect Easing Costs," Engineering News Record
(December 23, 1976), p. 87.
166. Chemical Marketing Reporter, Vol. 210, 10-26 (December 6
and December 20, 1976).
167. Smith, J. E., "Inventory of Energy Use in Wastewater Sludge
Treatment and Disposal," Industrial Water Engineering
(July/August, 1977).
168. Jones, J. L., Bomberger, D. C., Jr., and Lewis, F. M.,
"Energy Usage and Recovery in Sludge Disposal, Parts 1 & 2,"
Water and Sewage Works (July and August, 1977), pp. 44-47 and
42-46.
169. Hagen, R. M. and Roberts, E. B., "Energy Requirements for
Wastewater Treatment, Part 2," Water and Sewage Works (December,
1976), p. 52.
170. Banersi, S. K. and O'Conner, J. T., "Designing More Energy
Efficient Wastewater Treatment Plants," Civil Engineering
(September, 1977), p. 76.
171. "Electrical Power Consumption for Municipal Wastewater
Treatment," EPA-R2-73-281 (1973).
172. Hillmer, T. J., Jr., "Economics of Transporting Wastewater
Sludge," Public Works (September, 1977), p. 110.
173. Ettlich, W. F. , "Economics of Transport Methods of Sludge,"
Proceedings of the Third National Conference on Sludge Manage-
ment, Disposal and Utilization (December 14-16, 1976), pp. 7-14.
174. NUS/Rice Laboratory, "Sampling Prices," Pittsburgh, PA
(1978).
175. WARF Instruments, Inc., "Pricing Lists and Policies,"
Madison, WI (June, 15, 1973).
176. Orlando Laboratories, Inc., "Service Brochure and Fee
Schedule #16," Orlando, FL (January 1, 1978).
177. St. Louis Testing Laboratory, "Water and Wastewater
Analysis - Fee Schedule," St. Louis, MO (August, 1976).
178. Ecology Audits, Inc., "Laboratory Services - Individual
Component Analysis," Dallas, TX (August, 1976).
179. Laclede Gas Company, (Lab Div.), "Laboratory Pricing
Schedule," St. Louis, MO (August, 1977).
527
-------
180. Industrial Testing Lab, Inc., "Price List," St. Louis, MO
(October, 1975).
181. Luther, P. A., Kennedy, D. C., and Edgerley, E., Jr.
"Treatability and Functional Design of a Physical-Chemical
Wastewater Treatment System for a Printing and Photodeveloping
Plant," 31st Purdue Industrial Waste Conference, pp. 876-884
(1976).
182. Hindin, E. and Bennett, P. J., "Water Reclamation by
Reverse Osmosis," Water and Sewage Works, 116, 2, 66 (February,
1969).
183. Cruver, J. E. and Nusbaum, I., "Application of Reverse
Osmosis to Wastewater Treatment," Journal Water Pollution Control
Association, 476, 2, 301 (February, 1974).
184. Cruver, J. E., "Reverse Osmosis - Where It Stands Today,"
Water and Sewage Works, 120, 10, 74 (October, 1973).
185. Vanderborght, B. M. and Vangrieken, R. E., "Enrichment of
Trace Metals by Adsorption on Activated Carbon," Analytic
Chemistry, 49, 2, 311 (February, 1977).
186. Hannah, S. A., Jelus, by Physical and Chemical Treatment
Processes," Journal Water Pollution Control Federation, 50, 11,
2297 (1978).
187. Argo, D. G. and Gulp, G. L., "Heavy Metals Removed in
Wastewater Treatment Processes - Parts 1 and 2," Water and Sewage
Works, August, 1972, pp. 62-65, and September, 1972, pp. 128-132.
188. Hager, D. G., "Industrial Wastewater Treatment by Granular
Activated Carbon," Industrial Water Engineering, pp. 14-28
(January/February, 1974) 189. Rohrer, K. L., "Chemical
Precipitants for Lead-Bearing Wastewaters," Industrial Water
Engineering, 12, 3 13 (1975).
189. Brody, M. A. and Lumpkins, R. J., "Performance of Dual-
Media Filters," Chemical Engineering Progress (April, 1977).
190. Bernardin, F. E., "Cyanide Detoxification Using Absorption
and Catalytic Oxidation," Journal Water Pollution Control
Federation, 45, 2 (February, 1973).
191. Russel, D. L., "PCB's: The Problem Surrounding Us and What
Must be Done," Pollution Engineering (August, 1977).
528
-------
192. Chriswell, C. D., et. al., "Comparison of Macroreticular
Resin and Activated Carbon as Sorbents," Journal American Water
Works Association (December, 1977).
193. Gehm, H. W. and Bregman, J. I., Handbook of Water Resources
and Pollution Control, Van Nostrand Reinhold Company (1976).
194. Considine, Douglas M., Energy Technology Handbook,
McGraw-Hill Book Company, New York, c.1977, pp. 5-173-5-181.
195. Absalom, Sandra T., Boron, U.S. Dept. of the Interior,
Bureau of Mines, Washington, D.C., May, 1979.
196. Rathjen, John A., Antimony, U.S. Dept. of the Interior,
Bureau of Mines, Washington, D.C., June, 1979.
197. Harris, Keith L., Cesium, U.S. Dept. of the Interior,
Bureau of Mines, Washington, D.C., May, 1979.
529
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SECTION XVI
GLOSSARY
This section is an alphabetical listing of technical terms (with
definitions) used in this document which may not be familiar to
the reader.
4-AAP Colorimetric Method
An analytical method for total phenols and total phenolic com-
pounds that involves reaction with the color developing agent
4-aminoantipyrine.
Acidity
The quantitative capacity of aqueous solutions to react with
hydroxyl ions. Measured by titration with a standard solution of
a base to a specified end point. Usually expressed as milligrams
per liter of calcium carbonate.
The Act
The Federal Water Pollution Control Act Amendments of 1972 as
amended by the Clean Water Act of 1977 (PL 92-500).
Amortization
The allocation of a cost or account according to a specified
schedule, based on the principal, interest and period of cost
allocation.
AnalyticalQuantification Level
The minimum concentration at which quantification of a specified
pollutant can be reliably measured.
Anglesite
A mineral occurring in crystalline form or as a compact mass.
Antimonial Lead
An alloy composed of lead and up to 25 percent antimony.
Backwashing
The operation of cleaning a filter or column by reversing the
flow of liquid through it and washing out matter previously
trapped.
531
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Baghouses
The area for holding bag filters, an air pollution control
equipment device.
Ball Mill
Pulverizing equipment for the grinding of raw material. Grinding
is done by steel balls, pebbles, or rods.
Barton Process
A process for making lead oxide to be used in secondary lead
oxide batteries. Molten lead is fed, agitated, and stirred in a
pot with the resulting fine droplets oxidized. Material is col-
lected in a settling chamber where crystalline varieties of lead
oxide are formed.
Batch Treatment
A waste treatment method where wastewater is collected over a
period of time and then treated prior to discharge. Treatment is
not continuous, but collection may be continuous.
Bench Scale Pilot Studies
Experiments providing data concerning the treatability of a
wastewater stream or the efficiency of a treatment process con-
ducted using laboratory-size equipment.
Best Available Demonstrated Technology (BDT)
Treatment technology upon new source performance standards as
defined by Section 306 of the Act.
Best Available Technology Economically Achievable (BAT)
Level of technology applicable to toxic and nonconventional pol-
lutants on which effluent limitations are established. These
limitations are to be achieved by July 1, 1984 by industrial dis-
charges to surface waters as defined by Section 301 (b)(2)(C) of
the Act.
Best Conventional Pollutant Control Technology (BCT)
Level of technology applicable to conventional pollutant effluent
limitations to be achieved by July 1, 1984 for industrial dis-
charges to surface waters as defined in Section 301(b)(2)(E) of
the act.
532
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Best Management Practices (BMP)
Regulations intended to control the release of toxic and hazard-
ous pollutants from plant runoff, spillage, leaks, solid waste
disposal, and drainage from raw material storage.
Best Practicable Control Technology Currently Available (BPT)
Level of technology applicable to effluent limitations to have
been achieved by July 1, 1977 (originally) for industrial dis-
charges to surface waters as defined by Section 301(b)(1)(A) of
the Act.
Betterton Process
A process used to remove bismuth from lead by adding calcium and
magnesium. These compounds precipitate the bismuth which floats
to the top of the molten bath where it can be skimmed from the
molten metal.
Billet
A long, round slender cast product used as raw material in
subsequent forming operations.
Biochemical Oxygen Demand (BOD)
The quantity of oxygen used in the biochemical oxidation of
organic matter under specified conditions for a specified time.
Blast Furnace
A furnace for smelting ore concentrates. Heated air is blown in
at the bottom of the furnace, producing changes in the combustion
rate.
Blister Copper
Copper with 96 to 99 percent purity and appearing blistered; made
by forcing air through molten copper matte.
Slowdown
The minimum discharge of circulating water for the purpose of
discharging dissolved solids or other contaminants contained in
the water, the further buildup of which would cause concentration
in amounts exceeding limits established by best engineering
practice.
533
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Calcining
Heating to a high temperature without fusing so as to remove
material or make other changes.
Carbon Reduction
The process of using the carbon of coke as a reducing agent in
the blast furnace.
Cementation
A proces in which metal is added to a solution to initiate the
precipitation of another metal. For example, iron may be added
to a copper sulfate solution to precipitation Cu:
CuSC>4 + Fe -> Cu + FeSC>4
Cerussite
A mineral occurring in crystalline form and made of lead
carbonate.
Charged
Material that has been melted by being placed inside a furnace.
Charging Scrap
Scrap material put into a furnace for melting.
Chelation
The formation of coordinate covalent bonds between a central
metal ion and a liquid that contains two or more sites for com-
bination with the metal ion.
Chemical Oxygen Demand (COD)
A measure of the oxygen-consuming capacity of the organic and
inorganic matter present in the water or wastewater.
Cold-Crucible Arc Melting
Melting and purification of metal in a cold refractory vessel or
pot.
Colloid
Suspended solids whose diameter may vary between less than one
micron and fifteen microns.
534
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Composite Samples
A series of samples collected over a period of time but combined
into a single sample for analysis. The individual samples can be
taken after a specified amount of time has passed (time compo-
sited) , or after a specified volume of water has passed the sam-
pling point (flow composited). The sample can be automatically
collected and composited by a sampler or can be manually
collected and combined.
Consent Decree (Settlement Agreement)
Agreement between EPA and various environmental groups, as insti-
tuted by the United States District Court for the District of
Columbia, directing EPA to study and promulgate regulations for
the toxic pollutants (NRDC, Inc. v. Train, 8 ERC 2120 (D.D.C.
1976), modified March 9, 1979, 12 ERC 1833, 1841).
Contact Water
Any water or oil that comes into direct contact with the alumi-
num, whether it is raw material, intermediate product, waste
product, or finished product.
Continuous Casting
A casting process that produces sheet, rod, or other long shapes
by solidifying the metal while it is being poured through an
open-ended mold using little or no contact cooling water. Thus,
no restrictions are placed on the length of the product and it is
not necessary to stop the process to remove the cast product.
Continuous Treatment
Treatment of waste streams operating without interruption as
opposed to batch treatment. Sometimes referred to as flow-
through treatment.
Contractor Removal
Disposal of oils, spent solutions, or sludge by a commercial
firm.
Conventional Pollutants
Constituents of wastewater as determined by Section 304(a)(4) of
the Act, including but not limited to pollutants classified as
biological-oxygen-demanding, oil and grease, suspended solids,
fecal coliforms, and pH.
535
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Converting
The process of blowing air through molten metal to oxidize
impurities.
Cooling Tower
A hollow, vertical structure with internal baffles designed to
break up falling water so that it is cooled by upward-flowing air
and the evaporation of water.
Copper Matte
An impure sulfide mixture formed by smelting the sulfide ores in
copper.
Cupelled
Refined by means of a small shallow porous bone cup that is used
in assaying precious metals.
Cupola Furnace
A vertical cylindrical furnace for melting materials on a small
scale. This furnace is similar to a reverberatory furnace but
only on a smaller scale.
Cyclones
A funnel-shaped device for removing particulates from air or
other fluids by centrifugal means.
Data Collection Portfolio (dcp)
The questionnaire used in the survey of the aluminum forming
industry,
Degassing
The removal of dissolved hydrogen from the molten aluminum prior
to casting. This process also helps to remove oxides and
impurities from the melt.
Direct Chill Casting
A method of casting where the molten aluminum is poured into a
water-cooled mold. The base of this mold is the top of a
hydraulic cylinder that lowers the aluminum first through the
mold and then through a water spray and bath to cause solidifica-
tion. The vertical distance of the drop limits the length of the
ingot. This process is also known as semi-continuous casting.
536
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Direct Discharger
Any point source that discharges to a surface water.
Pore
Gold and silver bullion remaining in a cupelling furnace after
oxidized lead is removed.
Dross
Oxidized impurities occurring on the surface of molten metal.
Drying Beds
Areas for dewatering of sludge by evaporation and seepage.
Effluent
Discharge from a point source.
Effluent Limitation
Any standard (including schedules of compliance) established by a
state or EPA on quantities, rates, and concentrations of chemi-
cal, physical, biological, and other constituents that are dis-
charged from point sources into navigable waters, the waters of
the contiguous zone, or the ocean.
Electrolysis
A method of producing chemical reactions by sending electric
current through electrolytes or molten salt.
Electrolytic Refining
A purification process in which metals undergo electrolysis.
Electrolytic Slime
Insoluble impurities removed from the bottom of an electrolytic
cell during electrolytic refining.
Electron Beam Melting
A melting process in which an electron beam is used as a heating
source.
537
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Electrostatic Precipitator (ESP)
A gas cleaning device that induces an electrical charge on a
solid particle which is then attracted to an oppositely charged
collector plate. The collector plates are intermittently
vibrated to discharge the collected dust to a hopper.
End-of-Pipe Treatment
The reduction of pollutants by wastewater treatment prior to dis-
charge or reuse.
Film Stripping
Separation of silver-bearing material from scrap photographic
film.
Fluid Bed Roaster
A type of roaster in which the material is suspended in air
during roasting.
Fluxes
Substances added to molten metal to help remove impurities and
prevent excessive oxidation, or promote the fusing of the metals.
Galena
A bluish gray mineral occurring in the form of crystals, masses,
or grains; it constitutes the principal ore of lead.
Gangue
Valueless rock and mineral mined with ore. When separated from
ore, the material is known as "slag."
Gas Chromatography/Mass Spectroscopy (GC/MS)
Chemical analytical instrumentation used for quantitative organic
analysis.
Grab Sample
A single sample of wastewater taken without regard to time or
flow.
Hardeners
Master alloys that are added to a melt to control hardness.
538
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Harris Process
A process in which sodium hydroxide and sodium nitrate are added
to molten lead to soften or refine it. These two compounds react
with impurities in the molten metal forming a slag that floats to
the top of the molten metal.
Humidification Chamber
A chamber in which the water vapor content of a gas is increased.
Hydrogenation
The addition of hydrogen to a molecule.
Hydrometallurgical
The use of wet processes to treat metals.
Indirect Discharger
Any point source that discharges to a publicly owned treatment
works.
Inductively-Coupled Argon Plasma Spectrophotometer (ICAP)
A laboratory device used for the analysis of metals.
Ingot
A large, block-shaped casting produced by various methods.
Ingots are intermediate products from which other products are
made.
In-Process Control Technology
Any procedure or equipment used to conserve chemicals and water
throughout the production operations, resulting in a reduction of
the wastewater volume.
Li tharg e
A yellowish compound with a crystalline form; also known as lead
monoxide.
Matte
A metal sulfide mixture produced by smelting sulfide ores.
539
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Mischmetal
A rare earth metal alloy comprised of 94 to 99 percent of the
natural mixture of rare earth metals. The balance of the alloy
includes traces of other elements and 1 to 2 percent iron.
Mitsubishi Process
A process used in primary copper refining which incorporates
three furnaces to combine roasting, smelting, and converting into
one continuous proces. The Mitsubishi process results in reduced
smelting rates and heating costs.
New Source Performance Standards (NSPS)
Effluent limitations for new industrial point sources as defined
by Section 306 of the Act.
Nonconventional Pollutant
Parameters selected for use in performance standards that have
not been previously designated as either conventional or toxic
pollutants.
Non-Water Quality Environmental Impact
The ecological impact as a result of solid, air, or thermal pol-
lution due to the application of various wastewater technologies
to achieve the effluent guidelines limitations. Also associated
with the non-water quality aspect is the energy impact of waste-
water treatment.
NPDES Permits
Permits issued by EPA or an approved state program under the
National Pollution Discharge Elimination System.
Off-Gases
Gases, vapors, and fumes produced as a result of an aluminum
forming operation.
Oil and Grease (O&G)
Any material that is extracted by freon from an acidified sample
and that is not volatilized during the analysis, such as hydro-
carbons, fatty acids, soaps, fats, waxes, and oils.
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Outokumpu Furnaces
A furnace used for flash smelting, in which hot sulfide concen-
trate is fed into a reaction shaft along with preheated air and
fluxes. The concentrate roasts and smelts itself in a single
autogeneous process.
Parke* s Process
A process in which zinc is added to molten lead to form insoluble
zinc-gold and zinc-silver compounds. The compounds are skimmed
and the zinc is removed through vacuum de-zincing.
Pelletized
An agglomeration process in which an unbaked pellet is heat
hardened. The pellets increase the reduction rate in a blast
furnace by improving permeability and gas-solid contact.
£H
The pH is the negative logarithm of the hydrogen ion activity of
a solution.
Platinum Group Metals
A name given to a group of metals comprised of platinum,
palladium, rhodium, iridium, osmium, and ruthenium.
Pollutant Parameters
Those constituents of wastewater determined to be detrimental
and, therefore, requiring control.
Precious Metals
A generic term referring to the elements gold, silver, platinum,
palladium, rhodium, iridium, osmium, and ruthenium as a group.
Freeip i tat ion Supernatant
A liquid or fluid forming a layer above precipitated solids.
Priority Pollutants
Those pollutants included in Table 2 of Committee Print number
95-30 of the "Committee on Public Works and Transportation of the
House of Representatives," subject to the Act.
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Process Water
Water used in a production process that contacts the product, raw
materials, or reagents.
Production Normalizing Parameter (PNP)
The unit of production specified in the regulations used to
determine the mass of pollution a production facility may
discharge.
PSES
Pretreatment standards (effluent regulations) for existing
sources.
PSNS
Pretreatment standards (effluent regulations) for new sources.
Publicly Owned Treatment Works (POTW)
A waste treatment facility that is owned by a state or
municipality.
Pug Mill
A machine for mixing and tempering a plastic material by the
action of blades revolving in a drum or trough.
Pyrometallurgical
The use of high-temperature processes to treat metals.
Raffinate
Undissolved liquid mixture not removed during solvent refining.
Rare Earth Metals
A name given to a group of elements including scandium, yttrium,
and lanthanum to lutetium, inclusive.
Recycle
Returning treated or untreated wastewater to the production pro-
cess from which it originated for use as process water.
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Reduction
A reaction in which there is a decrease in valence resulting from
a gain in electrons.
Reuse
The use of treated or untreated process wastewater in a different
production process.
Reverberatory Furnaces
Rectangular furnaces in which the fuel is burned above the metal
and the heat reflects off the walls and into the metal.
Roasting
Heating ore to remove impurities prior to smelting. Impurities
within the ore are oxidized and leave the furnace in gaseous
form.
Rod
An intermediate aluminum product having a solid, round cross sec-
tion 9.5 mm (3/8 inches) or more in diameter.
Rotary Furnace
A circular furnace which rotates the workpiece around the axis of
the furnace during heat treatment.
Scrubber Liquor
The untreated wastewater stream produced by wet scrubbers clean-
ing gases produced by aluminum forming operations.
Shot Casting
A method of casting in which molten metal is poured into a
vibrating feeder, where droplets of molten metal are formed
through perforated openings. The droplets are cooled in a quench
tank.
Sintering
The process of forming a bonded mass by heating metal powders
without melting.
Skimmings
Slag removed from the surface of smelted metal.
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Slag
The product of fluxes and impurities resulting from the smelting
of metal.
Smelting
The process of heating ore mixtures to separate liquid metal and
impurities,
Soft Lead
Lead produced by the removal of antimony through oxidation. The
lead is characterized by low hardness and strength.
Spent Hypo Solution
A solution consisting of photographic film fixing bath and wash
water which contains unreduced silver from film processing.
Stationary Casting
A process in which the molten aluminum is poured into molds and
allowed to air-cool. It is often used to recycle in-house scrap.
Subcategorization
The process of segmentation of an industry into groups of plants
for which uniform effluent limitations can be established.
Supernatant
A liquid or fluid forming a layer above settled solids.
Surface Water
Any visible stream or body of water, natural or man-made. This
does not include bodies of water whose sole purpose is wastewater
retention or the removal of pollutants, such as holding ponds or
lagoons.
Surfactants
Surface active chemicals that tend to lower the surface tension
between liquids.
Sweating
Bringing small globules of low-melting constituents to an alloy
surface during heat treatment.
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Total Dissolved Solids (TDS)
Organic and inorganic molecules and ions that are in true solu-
tion in the water or wastewater.
Total Organic Carbon (TOG)
A measure of the organic contaminants in a wastewater. The TOG
analysis does not measure as much of the organics as the COD or
BOD tests, but is much quicker than these tests.
Total Recycle
The complete reuse of a stream, with makeup water added for
evaporation losses. There is no blowdown stream from a totally
recycled flow and the process water is not periodically or con-
tinuously discharged.
Total Suspended Solids (TSS)
Solids in suspension in water, wastewater, or treated effluent.
Also known as suspended solids.
Traveling Grate Furnace
A furnace with a moving grate that conveys material through the
heating zone. The feed is ignited on the surface as the grate
moves past the burners; air is blown in the charge to burn the
fuel by downdraft combustion as it moves continuously toward
discharge.
Tubing Blank
A sample taken by passing one gallon of distilled water through a
composite sampling device before initiation of actual wastewater
sampling.
Tuyeres
Openings in the shell and refractory lining of a furnace through
which air is forced.
Vacuum Dezincing
A process for removing zinc from a metal by melting or heating
the solid metal in a vacuum.
Venturi Scrubbers
A gas cleaning device utilizing liquid to remove dust and mist
from process gas streams.
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Volatile Substances
Materials that are readily vaporizable at relatively low
temperatures.
Wastewater Discharge Factor
The ratio between water discharged from a production process and
the mass of product of that production process. Recycle water is
not included.
Water Use Factor
The total amount of contact water or oil entering a process
divided by the amount of aluminum product produced by this pro-
cess. The amount of water involved includes the recycle and
makeup water.
Wet Scrubbers
Air pollution control devices used for removing pollutants as the
gas passes through the spray.
Zero Discharger
Any industrial or municipal facility that does not discharge
wastewater.
The following sources were used for defining terms in the
glossary:
Gill, G. B., Nonferrous Extractive Metallurgy. John Wiley &
Sons, New York, NY, 1980.
Lapedes, Daniel N., Dictionary of Scientific and Technical Terms,
2nd edition. New York, NY, McGraw-Hill Book Co., 1978.
McGannon, Harold E., The Making, Shaping, and Treating of Steel,
9th edition. Pittsburgh, PA, U.S. Steel Corp., 1971.
',, b fc .yifanmenta! Protection Agency
K :?,..-*• V, Library
2i;-J Scuth Dc.-.rborn Street
Chicago, Illinois 60604
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