-------
TABLE V-27
CHARACTERISTICS OF LEAD
CONTINUOUS STRIP CASTING PROCESS WASTEWATERS
Raw Wastewater
Plant:
Flow (1/kkg):
Sample Point:
Pollutants
120 Copper
122 Lead
128 Zinc
Oil and Grease
TSS
pH (units)
mg/1
0.046
0.848
0.014
<5
5
10145
25.3
S03
kg/kkg
(lbs/1000 Ibs)
0.000001
0.000021
0.0000004
V
<0.000126
0.000126
7.7
Note: A representative discrete continuous strip casting
treated effluent sample could not be obtained.
224
-------
TABLE V-28
CHARACTERISTICS OF MAGNESIUM
GRINDING SCRUBBER PROCESS WASTEWATERS
Raw Wastewater
Plant:
Production (kkg/day):
Flow (1/kkg):
Sample Points:
Pollutants
128 Zinc
Manganese
Oil and Grease
TSS
pH (Units)
Treated Effluent
Plant:
Flow:
Sample Points:
C&TT:
Pollutants
128 Zinc
Manganese
Oil and Grease
TSS
pH (Units)
mg/1
1.19
0.29
4.0
37.0
mg/1
08146
0.726 (0.80 TPD)
6737 (1616 GPT)
B
9.4-10.0
08146
None,
NO TREATMENT
kg/kkg
(lbs/1000 Ibs)
0.00802
0.00196
0.030
0.251
kg/kkg
(lbs/1000 Ibs)
225
-------
TABLE V-29
CHARACTERISTICS OF MAGNESIUM
DUST COLLECTION PROCESS WASTEWATERS
Raw Wastewater
Plant:
Sand Handled (kkg/day):
Flow (1/kkg):
Sample Points:
Pollutants
128 Zinc
Phenols (4AAP)
Sulfide
Oil and Grease
TSS
pH (Units)
Treated Effluent
Plant:
Flow:
Sample Points:
C&TT:
Pollutants
128 Zinc
Phenols (4AAP)
Sulfide
Oil and Grease
TSS
pH (Units)
mg/1
0.36
1.141
12.6
11.0
26.0
mg/1
08146
90.8 (100 TPD)
90 (21.6 GPT)
C
7.4-7.8
08146
None
NO TREATMENT
kg/kkg
(lbs/1000 Ibs)
0.000033
0.000103
0.00113
0.000992
0.00232
kg/kkg
(lbs/1000 Ibs)
226
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-------
TABLE V-31
CHARACTERISTICS OF ZINC
MELTING FURNACE SCRUBBER
PROCESS WASTEWATERS
Raw Wastewater
Plant:
Production (kkg/day):
Flow (1/kkg):
Sample Points:
Pollutants
021 2,4,6-trichlorophenol
022 Parachlorometacresol
031 2,4-dichlorophenol
034 2,4-dimethylphenol
055 Naphthalene
065 Phenol
067 Butyl benzyl phthalate
128 Zinc
Phenols (4AAP)
Oil and Grease
TSS
pH (Units)
Treated Effluent
Plant:
Flow (1/kkg):
Sample Points:
C&TT:
Pollutants
021 2,4,6-trichlorophenol
022 Parachlorometacresol
031 2,4-dichlorophenol
034 2,4-dimethylphenol
055 Naphthalene
065 Phenol
067 Butyl benzyl phthalate
128 Zinc
Phenols
Oil and Grease
TSS
pH (Units)
18139
59.7 (65.7 TPD)
2925 (701 GPT)
B
mg/1
1.374
0.081
1.268
4.342
1.623
15.697
0.080
18.54
90.744
760
429
4.6-4.7
kg/kkg
(lbs/1000 Ibs)
0.00402
0.000273
0.00376
1.269
0.00474
0.0459
0.000234
0.0542
0.265
2.221
1.254
18139
2925 (701 GPT)
(B/(B+C+D+E+H))G
OS, SB
kg/kkg
mg/1 (lbs/1000 Ibs)
0.617
ND
0.220
0.096
0.049
1.65
0.049
13.24
14.194
845
325
0.00180
0.000
0.000643
0.000281
0.000144
0.00484
0.000144
0.0387
0.0415
2.470
0.949
4.6-8.2
Note: For definitions of C&TT codes refer to Table 111-21.
ND: Not Detected
223
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SECTION VI
SELECTION OF POLLUTANTS
Section V presented the pollutants to be examined for possible
regulation along with data from plant sampling visits and
chemical analyses.
This section discusses those pollutants which were not found in
the raw process wastewaters or were detected at such small levels
that their presence could not be quantified. Additionally,
pollutants known to be present in raw process wastewaters are
discussed. Toxic pollutants known to be present are discussed in
numerical order, followed by nonconventional pollutants and then
conventional pollutant parameters, each in alphabetical order.
• •' *"'n •• • • r1' •• '' • !!• j L " H" j_ .HI i, , , , L ...•".
Finally, the pollutant parameters selected for consideration for
specific regulation for the discharge alternatives discussed in
Sections IX through XIII of this document, and those eliminated
from further consideration in each subcategory are discussed.
The rationale for those selections is also presented.
POLLUTANTS NOT DETECTED IN RAW PROCESS WASTEWATERS
Table VI-1 lists the 21 pollutants that were not detected in any
raw process wastewater samples in this category. These
pollutants have been eliminated from further consideration for
regulation* ~ ; -=
POLLUTANTS DETECTED IN
RAW PROCESS WASTEWATERS BELOW QUANTIFIABLE LIMITS
Table VI-2 lists the 14 pollutants that were found in raw process
wastewaters at npnquantifiable levels in all raw process
wastewaters samples analyzed in this category, These pollutants
have also been eliminated from further consideration for
regulation.
POLLUTANTS PRESENT IN RAW PROCESS WASTEWATERS
Table VI-3 lists those pollutants present in quantifiable in raw
process wastewaters. A pollutant is considered to be present if
any of the following three conditions are satisfied: 1) the
average raw wastewater concentration of a pollutant for all
plants sampled within the subcategory is 0.010 mg/1 or greater,
2) the pollutant is identified as "known to be present" in the
plant DCP response, or 3) examination of the metal molding and
287
-------
casting manufacturing processes indicates that a pollutant is
associated with a specific manufacturing process due to the
nature of the manufacturing process, raw materials used, air
pollution control devices, or other production related
parameters.
Ninty-two toxic pollutants were found in quantifiable amounts in
wastewaters of the metal molding and casting category. These
pollutants are listed in Table VI-3 and are discussed briefly
below. These discussions: provide details regarding the process
origin of the pollutant; discuss whether the pollutant is a
naturally occurring • element, processed metal, or process
chemical; describe the general physical properties and the form
of each pollutant; describe the toxic effects of the pollutant in
humans and other animals; and discuss the behavior of each
pollutant in POTWs at the concentrations that might be expected
from industrial dischargers. The literature relied upon for
these discussions is listed in Section XV. Particular attention
has been given to documents generated by the EPA Criteria and
Standards Division, and the Monitoring and Data Support Division.
i
Acenaphthene(1). Acenaphthene (1,2-dihydroacenaphthylene, or
1,8-ethylene-naphthalene) is a polynuclear aromatic hydrocarbon
(PAH) with molecular weight of 154 and a formula of C12Hj0. The
structure is:
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
temperature, with a melting range of 95 to 97°C (203 to 207°F)
and a boiling, range of 278 to 280°C (532 to 536°F). Its vapor
pressure at room temperature is less 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. Limited acute ;and chronic toxicity
288
-------
data for freshwater aquatic life show that adverse effects occur
at higher concentrations than Jthose cited for human health risks.
No detailed study of acenaphthene behavior in POTWs is available.
However, it has been demonstrated that none of the organic
priority pollutants studied so far can be broken down by
biological treatment processes as readily as fatty acids,
carbohydrates, or proteins. Many of the priority 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 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
acenaphthene. No evidence is available to draw conclusions about
its possible toxic or inhibitory effect on POTW operations.
Its water solubility would allow acenaphthene present in the
influent to. pass through a POTW into the effluent. The
hydrocarbon 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 polypoidal chromosome
number. However, it is not expected that land application of
sewage sludge containing acenaphthene, at the low concentrations
which are to be expected in a POTW sludge, would result in any
adverse effects on animals ingesting plants grown in such soil.
Benzene (4). Benzene (C6H«) 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
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
manufacture. 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
published studies. Most studies relate effects of inhaled
benzene vapors. These effects include nausea, loss of muscle
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coordination, and excitement, followed by depression and coma.
Death is usually the result of respiratory or cardiac failure.
Two specific blood disorders are related to benzene exposure.
One of these, acute myelogenous leukemia, represents a
carcinogenic effect of benzene. However, most human exposure
data is based on exposure in occupational settings, and benzene
carcinogenesis is not considered to be firmly established.
Oral administration of benzene to laboratory animals produced
leukopenia, a reduction in the number of leukocytes in the blood.
Subcutaneous injection of benzene-oil solutions has produced
suggestive, but not conclusive, evidence of benzene
carcinogenesis.
Benzene demonstrated teratogenic effects in laboratory animals,
and mutagenic effects in humans and other animals.
For maximum protection of human health from the potential
carcinogenic effects of exposure to benzene, through ingestion of
water and contaminated aquatic organisms, the ambient water
concentration is zero. Concentrations of benzene estimated to
result in additional lifetime cancer risk at levels of 10~7,
10-«, and 10~s are 0.00015 mg/1, 0.0015 mg/1, and 0.015 mg/1,
respectively. If contaminated aquatic organisms alone are
consumed, excluding the consumption of water, the water
concentration should be less than 0.478 mg/1 to keep the lifetime
cancer risk below 10~s. Available data show that adverse effects
on aquatic life occur at concentrations higher than those cited
for human risks.
Some studies have been reported regarding the behavior of benzene
in POTWs. Biochemical oxidation of benzene under laboratory
conditions, at concentrations of 3 to 10 mg/1, produced 24, 27,
24, and 29 percent degradation in 5, 10, 15, and 20 days,
respectively, using unacclimated seed cultures in fresh water.
Degradation of 58, 67, 76, and 80 percent was produced in the
same time periods using acclimated seed cultures. Other studies
produced similar results. Based on these data and general
conclusions relating molecular structure to biochemical
oxidation, it is expected that biological treatment in POTWs will
remove benzene readily from the water. Other reports indicate
that most of the benzene entering a POTW is removed to the
sludge, and that influent concentrations of 1 g/1 inhibit sludge
digestion. An EPA study of the fate of priority pollutants in
POTWs reveals removal efficiencies of 70 to 98 percent for three
POTWs where influent benzene levels were 5 x 10~3 to 143 x 10~3
mg/1. Four other POTW samples had influent benzene
concentrations of 1 or 2 x 10~3 mg/1, and removals appeared
indeterminate because of the limits of quantification for
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analyses. There is no information about possible effects of
benzene on crops grown in soils amended with sludge containing
benzene.
Benzidine (5). Benzidine (NHZ(C6H4)2NH2) is a grayish-yellow,
white or reddish-gray crystalline powder. It melts at 127°C
{260°F), and boils at 400°C (752<>F). This chemical is soluble in
hot water, alcohol, and ether, but only slightly soluble in
water. It is derived by: (a) reducing nitrobenzene with zinc
dust in an alkaline solution followed by distillation; (b) the
electrolysis of nitrobenzene, followed by distillation; or, (c)
the nitration of diphenyl followed by reduction of the product
with zinc dust in an alkaline solution, with subsequent
distillation. It is used in the synthesis of a variety of
organic chemicals, such as stiffening agents in rubber
compounding.
Available data indicate that benzidine is acutely toxic to
freshwater aquatic life at concentrations as low as 2.50 mg/1 and
would occur at lower concentrations among species that are more
sensitive than those tested. However, no data are available
concerning the chronic toxicity to sensitive freshwater and
saltwater aquatic life.
For the maximum protection of human health from the potential
carcinogenic effects due to exposure to benzidine, through the
ingestion of contaminated water and contaminated aquatic
organisms, the ambient water concentration should be zero.
Concentrations of this pollutant estimated to result in
additional lifetime cancer risk at risk levels of TO-5, 10-«, and
TO-* are 0.0000012 mg/1, 0.00000012 mg/1, and 0.000000012 mg/1
respectively.
With respect to treatment in POTWs, laboratory studies have shown
that benzidine is amenable to treatment via biochemical
oxidation. The expected 30-day average treated effluent
concentration is 0.025 mg/1.
Carbon tetrachloride (6). Carbon tetrachloride (CC14), also
called tetrachloromethane, is a colorless liquid produced
primarily 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 mg/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
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intermediate for production of chlorofluoromethanes for
refrigerants, 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
five grams - has frequently proven 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
discomfort or pain.
Data concerning teratogenicity and mutagenicity of carbon
tetrachloride are scarce and inconclusive. However, carbon
tetrachloride has been demonstrated to be carcinogenic in
laboratory animals. The liver was the target organ.
For the maximum protection of human health from the potential
carcinogenic effects of exposure to carbon tetrachloride, through
ingestion of water and contaminated aquatic organisms, the
ambient water concentration is zero. Concentrations of carbon
tetrachloride estimated to result in additional lifetime cancer
risk at risk levels of 10~7, 10~«, and 10~5 are 0.000026 mg/1,
0.00026 mg/1, and 0.0026 mg/1, respectively.
Data on the behavior of carbon tetrachloride in POTWs are not
available. Many of the organic priority pollutants have been
investigated, at least in laboratory scale studies, at
concentrations higher than those expected to be found in 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 a
moderate degree of removal of carbon tetrachloride in POTWs. No
information 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 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 (C6H5C1), also called
monochlorobenzene is a clear, colorless, liquid manufactured by
the liquid phase chlorination of benzene over a catalyst. It
boils at 132°C (270°F) and has a vapor pressure of 12.5 mm Hg at
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25°C. It is almost insoluble in water (0.5 g/1 at 30°C), but
dissolves in hydrocarbon solvents. IkS. annual production is
near 150,000 tons.
Principal uses of chlorobenzene are as a solvent and as an
intermediate 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 tohuman 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
chlorobenzene, 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
carcinogenic 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.
Limited data are available on which to base conclusions about the
behavior of chlorobenzene in POTWs. Laboratory studies of the
biochemical oxidation of chlorobenzene have been carried out at
concentrations greater than those expected to normally be present
in POTW influents. 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 molecular structure to
biochemical oxidation, it is concluded that chlorobenzene will be
removed to a moderate degree by biological treatment in POTWs. A
substantial percentage of the chlorobenzene remains intact and is
expected to volatilize from the POTW in aeration processes. The
estimated half-life of chlorobenzene in water, based on water
solubility, vapor pressure and molecular weight, is 5.8 hours.
1,2,4-trichlorobenzene (8). 1,2,4-trichlorobenzene (C6H3C13,
1,2,4-TCB) is a liquid at room temperature, solidifying to a
crystalline solid at 17°C (3°F) and boiling at 214°C (417°F). 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
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is used in limited quantities as a solvent and as a dye carrier
in the textile industry. It is also used as a heat transfer
medium and as a transformer fluid. The compound can be
selectively chlorinated to 1,2,4,5-tetrachlorobenzene using
iodine plus antimony trichloride as catalysts.
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 POTWs 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
wastewaters. 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 POTWs.
1,2-dichloroethane (10). 1,2-dichloroethane (C1CH2CH2C1) is a
colorless, oily liquid with a chloroform-like odor and a sweet
taste. Stable in the presence of water, alkalies, acids, or
actively reacting chemicals, it is resistant to oxidation.
Miscible with most common solvents, it is only slightly soluble
in water. It boils at 83.5°C (182°F), flashes at 21°C (70°F) and
has a vapor pressure of 100 mm Hg at 29.4°C- This chemical is
derived by the action of chlorine on ethylene with subsequent
distillation, with ethylene dibromide as a catalyst. It is used
as a solvent for oils, resins, gums, and other products and for
metal degreasing.
Available data indicate that acute toxicity to freshwater aquatic
life occurs at 118 mg/1, and that chronic toxicity occurs at a
concentration of 29 mg/1. Available data for saltwater fish and
invertebrate species indicate that acute toxicity occurs at 113
mg/1.
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For the maximum protection of human health from the potential
carcinogenic effects due toi exposure to 1,2-dichloroethane,
through the ingestion of contaminated water and contaminated
aquatic organisms, the ambient water concentration should be
zero. Concentrations of this pollutant estimated to result in
additional lifetime cancer risk at risk levels of J0-s> TO «, and
lO-^ are 0.0094 mg/1, 0.00094 mg/1, and 0.000094 mg/1
respectively.
With respect to treatment in POTWs, laboratory studies have shown
that V,2-dichloroethane is only moderately amenable to treatment
via biochemical oxidation. This is corroborated by the Physical
property data presented above. It should be noted that the
optimum estimated 30-day average treated effluent concentration.
of 0.10 mg/1 is greater than the level at which this pollutant
was found in any foundry process wastewater.
l,l,l-trichloroethane(n). 1,1,1-trichloroethane is^one of the
t££—possible" trichloroethanes. It is manufactured by
hydrochlorinating vinyl chloride to 1 1-dichloroethane, ^ich^is
then chlorinated to the desired product. 1,1,1-trichlproethane
is a liquid at room temperature with a vapor pressure of 96 mm Hg
at 20°C and a boiling point of 74oc. Its formula is CCljCHa- Jt
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
available for determining toxicity of ^"^ted
1 1 1-trichloroethane, and those data are all for the compound
itself, not. for 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 l,1-trichloroethane, ingested through the consumption of water
and fish, the ambient water criterion is 15.7 mg/1. The
criterion is based on bioassay for possible carcinogenicity.
No detailed study of 1,1,1-trichloroethane behavior in POTWs is
available. However, it has been demonstrated that none of the
organic priority pollutants of this type can be broken down by
biological treatment processes as readily as fatty acids,
carbohydrates, or proteins.
Biochemical oxidation of many of the organic priority pollutants
has been investigated, at least in laboratory scale studies, at
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concentrations higher than commonly expected in municipal
wastewater. 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 conclusions about its possible toxic or inhibitory
effect on POTW operations. 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,
but no detailed study, is the volatilization of the lower
molecular weight organics from POTWs. If 1,1,1-trichloroethane
is not biodegraded, it will volatilize during aeration processes
in the POTW.
1,1-dichloroethane(13). l,1-dichloroethane, also called
ethylidene dichloride and ethylidene chloride, is a colorless
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
commercially 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. v
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-dichloroethane), but its use as an anesthetic 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.
l
Data on the behavior of 1,1-dichloroethane in POTWs are not
available. Many of the organic priority 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 organic priority pollutants. The conclusion reached by study
of the limited data is that biological treatment produces only a
moderate removal of 1,1-dichloroethane in POTWs by degradation.
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The high vapor pressure of 1,1-dichloroethane is expected to
result in volatilization of some of the compound from aerobic
processes in POTWs. 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
trichloride or vinyl trichloride. It is used as a solvent for
fats, oils, waxes, and resins, in the manufacture of
1,1-dichloroethylene, and as an intermediate in organic
synthesis.
1,1,2-trichloroethane is a clear, colorless liquid at room
temperature with a vapor pressure of 16.7 mm Hg at 20°C, and a
boiling point of 113°C. It is insoluble in water and very
soluble in organic solvents. The formula is CKC1ZCEZC1.
Human toxicity data for 1,1,2-trichloroethane does not appear in
the literature. The compound does produce liver and kidney
damage in laboratory animals after intraperitoneal
administration. No literature data were found concerning
teratogenicity or mutagenicity of l,1,2-trichloroethane.
However, mice treated with 1,1,2-trichloroethane showed increased
incidence of hepatocellular carcinoma. Although bioconcentration
factors are not available 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 ambient water concentration is zero. Concentrations of this
compound estimated to result in additional lifetime cancer risks
at risk levels of 10~7, 10-«, and 10~s are 0.000027 mg/1, 0.00027
mg/1, and 0.0027 mg/1, respectively.
No detailed study of 1,1,2-trichloroethane behavior in POTWs 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 POTWs will
produce moderate removal of 1,1,2-trichloroethane.
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The lack of water solubility and the relatively high vapor
pressure may lead to removal of this compound from POTWs by
volatilization.
1,1,2,2-tetrachloroethane (15). 1,1,2,2-tetrachloroethane
(CHC12CHC12) is a heavy, colorless, mobile, nonflammable,
corrosive, toxic liquid. While it has a chloroform-like odor, it
is more toxic than chloroform. It is soluble in alcohol or
ether, but insoluble in water. It has no flash point, boils at
146.5°C (296°F) and has a vapor pressure of 5 mm Hg at 20.7°C.
It results from the interaction of acetylene and chlorine, with
subsequent distillation. This chemical is used in organic
synthesis, as a solvent, and for metal cleaning and degreasing.
Available freshwater data indicate that acute toxicity occurs at
concentrations of 9.32 rng/1, and that chronic toxicity occurs at
4.000 mg/1. Available saltwater data indicate that acute
toxicity occurs at 9.020 mg/1.
For the maximum protection of human health from the potential
carcinogenic effects due to exposure to 1,1,2,2-tetra-
chloroethane, through contaminated water and contaminated aquatic
organisms, the ambient water concentration should be zero.
Concentrations of this pollutant estimated to result in
additional lifetime cancer risk at risk levels of 10-s, 10-*, and
10-7 are 0.0017 mg/1, 0.00017 mg/1, and 0.000017 mg/1
With respect to treatment in POTWs, laboratory studies have shown
that 1,1,2,2-tetrachloroethane is not amenable to treatment via
biochemical oxidation. As this pollutant is insoluble in water,
any removal of this pollutant which would occur in a POTW, would
be related to physical treatment processes.
Bis(2-chloroethvl) ether (18). Bis(2-chloroethyl) ether
(C1CH2CH2OCH2CH2CL) is a colorless, stable, non-corrosive liquid
with an odor similar to that of ethylene dichloride. Its boils
at 178.5°C (353°F), flashes at 55°C (131°F) and has a vapor
pressure of 1 mm Hg at 23.5°C. It is miscible with most organic
solvents, immiscible with the paraffin hydrocarbons, and
insoluble with water. It is used as a solvent for oils, waxes,
and resins, as a wetting and penetrating compound, as a solvent
in the production of lubricating oils, and in the synthesis of
various organics.
The available data for this pollutant indicate that acute
toxicity to freshwater aquatic life occurs at concentrations as
low as 238 mg/1. No data are available concerning this
pollutant's chronic toxicity to freshwater aquatic life and acute
and chronic toxicity to saltwater aquatic life.
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For the maximum protection of human health from the potential
carcinogenic effects of exposure to this pollutant, through
ingestion of contaminated water and aquatic organisms, the
ambient water concentration should be zero. Concentrations of
this pollutant estimated to result in additional lifetime cancer
risks at risk levels of 10-*, 10-«, and 10-* are 0.0003 mg/1,
0.00003 mg/1, '0.000003 mg/1 respectively.
With respect to treatment in POTWs, laboratory studies have shown
that bis(2-chloroethyl) ether is not amenable to treatment•. via
biochemical oxidation. As this pollutant is insoluble in water,
any removal of this pollutant, which would occur in a POTW,, would
be related to physical treatment processes.
2.4.6-trichlorophenol (21). 2,4,6-trichlorophenol (Cl3C6H2OH,
abbreviated heTe"~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 (154°F) and is ,slightly
soluble in water (0.8 gm/1 at 25°C). This phenol doe* not
produce a color with 4-aminoantipyrene, therefore it does not,
contribute to the non-conventional pollutant parameter Total
Phenols." No data were found on production volumes.
2 4 6-TCP is used as a fungicide, bactericide, glue and wood
preservative, 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 interpentoneally.
Body temperature was elevated also. The compound also produced
inhibition of ATP production in isolated rat liver mitochondria,
increased mutation rates in one strain of bacteria, and produced
a genetic change in rats. No studies on teratogenicity were
found.
For the maximum protection of human health from the potential
carcinogenic effects of exposure to 2,4,6-trichlorophenol,
through ingestion of water and contaminated aquatic organisms^
the ambient water concentration should be zero. The estimated
levels which would result in increased lifetime cancer risks of
ID-* 10-6, and 10-s are 1.18 x 10-s mg/1, 1.18 x 10~* mg/1, and
1 18 x 10~3 mg/1, respectively. If contaminated aquatic
organisms alone are consumed, excluding the consumption of water,
the water concentration should be less than 3.6 x 10-* mg/1 to
keep the increased lifetime cancer risk below 10-s. Available
data show that adverse effects in aquatic species can occur at
9.7 x 10~4 mg/1.
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Although no data were found regarding the behavior of 2,4,6-TCP
in POTWs, studies of the biochemical oxidation of the compound
ftave been made on a 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 degradation using a phenol-adapted acclimated seed
culture. Based on these results, biological treatment in a POTW
is expected to produce a moderate degree of degradation. Another
study indicates that 2,4,6-TCP may be produced in POTWs by
chlorination of phenol during normal chlorination treatment.
Parachlorometacresol (22)_. Parachlorometacresol (C1C,H«OH) is
thought to be 4-chloro-3-methylphenol (4-chlorometacresol, or
2-chloro-5- hydroxytoluene, but is also used by some authorities
to refer to 6-chloro-3-methylphenol (6-chlorometacresol, or
4-chloro-3-hydroxytoluene), 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-hydroxytoluene. This compound is a
colorless crystalline solid melting at 66-68°C (151-154op) it
is slightly soluble in water (3.8 gm/1) and soluble in organic
solvents. This phenol reacts with 4-aminoantipyrene to give a
colored product and therefore contributes to the non-conventional
pollutant parameter designated "Total Phenols." No information on
manufacturing methods or volumes produced was found.
Parachlorometacresol (abbreviated here as PCMC) is marketed as a
microbicide, and was proposed as an antiseptic and disinfectant,
TnvS an 5??ty Year! a?°' Ifc is used in Slues, 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 proceeded by severe muscle tremors. At high dosages, kidney
damage occurred. On the other hand, an unspecified isomer of
chlorocresol, presumed to be PCMC, is used at a concentration of
0.15 percent to preserve mucous heparin, a natural product
administrated intravenously as an anticoagulant. The report does
not indicate the total amount of PCMC typically received No
information was found regarding possible teratogenicity, or
carcinogenicity of PCMC. ^il-y'
Two reports indicate that PCMC undergoes degradation in
biochemical oxidation treatments carried out at concentrations
higher than are expected to be encountered in POTW influents
One study showed 59 percent degradation in 3.5 hours, when a
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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 solution of PCMC in two weeks in- an. aerobic
activated sludge test system. No degradation of PCMC occurred
under anaerobic conditions. From a review of limited data, it is
expected that PCMC will be biochemically oxidized to a lesser-
extent .than domestic sewage by biological treatment in POTWs.
Chloroform(23). Chloroform 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 .<142.oF) 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 anesthetics. It is seldom used as
an anesthetic.
Toxic effects of chloroform on humans include central nervous
system depression, gastrointestinal irritation, liver and kidney
damage and possible cardiac sensitization to adrenalin
Carcinogenicity 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 lO^,
10-« and 10-5 were 0.000021 mg/1, 0.00021 mg/1, and 0.0021 mg/1,
respectively. If contaminated aquatic organisms alone are
consumed, excluding the consumption of water, the water
concentration should be less than 0.157 mg/rto.keep the
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.
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
wastewaters. After 5, 10, and 20 days no degradation _of
chloroform was< observed. The conclusion reached is_ that-
biological treatment produces little or no removal by degradation
of chloroform in POTWs. An EPA study of the fate of priority
pollutants in POTWs reveals removal efficiencies of 0 to^SO
percent for influent concentrations ranging from 5 to 46 x 10
mg/1 at seven POTWs.
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The high vapor pressure of chloroform is expected to result in
volatilization of the compound from aerobic treatment steps in
POTWs. Remaining chloroform is expected to pass through into the
POTW effluent.
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
distillation to separate it from the other principal product,
4-chlorophenol. 2-chlorophenol solidifies below 7°C (45°F) and
boils at 176°C (349°F). 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 non-conventional pollutant parameter "Total
Phenols." Production statistics could not be found.
2-chlorophenol is used almost exclusively as a chemical
intermediate in the production of pesticides and dyes.
Production of some phenolic resins uses 2-chlorophenol.
Very few data are available concerning the toxic effects of
2-chlorophenol on humans. The compound is more toxic to
laboratory mammals when administered orally, than when
administered subcutaneously or intravenously. This effect 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
restlessness, increased respiration rate, followed by motor
weakness and convulsions induced by-noise or touch, and coma.
Following lethal doses, kidney, liver, and intestinal damage were
observed. No studies were found which addressed the
teratogenicity 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 determinable relationship to results of oral
administration studies.
For controlling undesirable taste and odor quality of ambient
water due to the organoleptic properties of 2-chlorophenol in
water, the estimated level is 1 x 10~4 mg/1. Data show that
adverse effects on aquatic life occur at concentrations higher
than that cited for organoleptic effects.
Data on the behavior of 2-chlorophenol in POTWs are not
available. However, laboratory scale studies have been conducted
at concentrations higher than those expected to be found in
municipal 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,
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10, and 20 days, respectively. The conclusion, reached by the
study of thes4 limited data, and general observations, on all
organic priority pollutants relating molecular structure to ease
of biochemical oxidation, is that 2-chlorophenol is removed to a
high degree or completely by biological treatment in^ POTWs.
Undegraded 2-chlorophenol is expected to pass through POTWs into
the effluent because of the water solubility. Some
2-chloropheno~l is also expected to.be generated by chlorination
treatments of POTW effluents containing phenol.
T .2-trans-dichlQr0ethvlene(30) . 1 , 2
( trans- 1,2-DCE) — is a clear, colorless liquid with the formula
CHC1CHC1 Trans- Tf2-DCE is produced in a mixture with the
cis-isomer by chiorination- of acetylene. The cisTisomer has
distinctly different physical properties. Industrially, the
mixture is used rather than the separate isomers. Trans-1 ,2-DCE
has a boiling point of 48°C, and a vapor pressure of 324 mm Hg at
25°C.
The principal use" of 1 ,2-dich'loroethylene (mixed isomers) is to
produce vinyl chloride. It is used as a lead scavenger in
gasoline, as* a general solvent, and for the synthesis of various
other organic chemicals. When it is used as a solvent,
trans- 1 ,2-DCE can enter wastewater streams.
For the maximum protection of human health from the potential
effecte of exposure to 1 , 2-trans-dichloroethylene, through
ingest ion of water and contaminated aquatic organisms, the
ambient water concentration is zero. Concentrations of
T?2-l?ans-d?chloroethylene estimated to result in ad ditional
lifetime cancer risk at risk levels of 10-' f 10-', and 1 0 -are
33 x ID-* mg/1, 3.3 10-s mg/1, and 3.3 x 10 * mg/1,
respectively. If contaminated aquatic organisms, alone are
consumed excluding the consumption of water, the water
coSratf on should be less than 0.018 mg/1 to keep the lifetime.
cancer risk below .10-«. Limited acute and chronic toxicity data
for freshwater aquatic life show that adverse effects occur at
concentrations higher than those cited for human health risks.
The behavior of trans-1 , 2-DCE in POTWs has not ^been studied
However, its high vapor pressure is expected to result -in the
release of a significant percentage of this compound to the
atmosphere in any treatment involving aeration. Degradation o£
?he dichloroethylenes in air is reported to occur, with a
half-life of 8 weeks.
Biochemical oxidation of many of the organic priority pollutants
has been investigated in laboratory scale studies at
concentrations higher than would normally be expected in
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municipal wastewater. 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 effects of 1,2-trans-dichloroethylene on POTW
operations. It is expected that its low molecular weight and
degree of water solubility will result in trans-1,2-DCE passing
through a POTW to the effluent, if it is not degraded or
volatilized. Very little trans-1,2-DCE is expected to be found
in sludge from POTWs.
2,4-dichlorophenol (31 ). 2,4-dichlorophenol (C12C6H3OH) is a
colorless, crystalline solid manufactured by chlorination of
phenol dissolved in liquid sulfur dioxide or by chlorination of
molten phenol (a lower yield method). 2,4-dichlorophenol
(2,4-DCP) melts at 45°C (113°F) and has a vapor pressure of less
than 1 mm Hg at 25°C (vapor pressure equals 1 mm Hg at 53°C).
2,4-DCP is slightly soluble in water (4.6 g/1 at 20°C) and
soluble in many organic solvents. 2,4-DCP reacts to give a
strong color development with 4-aminoantipyrene, and therefore
contributes to the non-conventional pollutant designated "Total
Phenols." Annual U.S. production of 2,4-DCP is about 25,000 tons.
The principal use of 2,4-DCP is for the manufacture of the
herbicide 2,4-dichloro-phenoxyacetic acid (2,4-D) and other
pesticides.
Few data exist concerning the toxic effects of 2,4-DCP on humans.
Symptoms exhibited by laboratory animals injected with fatal
doses of 2,4-DCP included loss of muscle tone, followed by rapid,
then slow breathing. In vitro experiments revealed inhibition of
oxidative phosphorylation (a primary metabolic function) by
2,4-DCP in rat liver mitochondria and rat brain homogenates. No
studies were found which addressed the teratogenicity, or the
mutagenicity in mammals, of 2,4-DCP. The only studies of
carcinogenic properties of 2,4-DCP used dermal application, which
has no established relationship to oral administration results.
For the prevention of adverse effects due to the
properties of 2,4-dichlorophenol in water, the
0.0005 mg/1.
organoleptic
criterion is
Data on the behavior of 2,4-dichlorophenol in POTWs are not
available. However, laboratory scale studies have been conducted
at concentrations higher than those expected to be found in
municipal wastewaters. Biochemical oxidation produced
degradation of 70,72, and 72 percent -after 5,10 and 20 days,
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respectively, in one study. In another study, using an
acclimated phenol-adapted culture, 30 percent degradation was
measured after 3.5 hours. Based on these limited data, and on
general observations relating molecular structure to ease of
biological oxidation, it is concluded that 2 4-DCP is-removed to
a high degree or completely by biological treatment an POTWs.
Undegraded 2,4-DCP is-expected to pass through; POTWs to . the
effluent. Some 2,4-DCP may be formed in POTWs by chlorination of
effluents containing phenol. ' ;•
i > „-,,,',.
1 3-dichloropropylene (33). 1,3-dichloropropylene (CHC1:CHCH2C1)
is a colorleisTIquIdT" The boiling point of its cis-isomer is
104°C (219°F), while the boiling point of its trans-isomer is
112°C (234°F). It is derived from the chlorination of propylene.
While it is soluble in acetone, toluene, and octane, it is
insoluble in water. This chemical is used in various organic
synthesis procedures.
The available data indicate that acute and chronic toxicity to
freshwater aquatic life occur at concentrations as^ low as 6.06
mq/1 and 0.244 mg/1 respectively. The available data for this
pollutant indicate that acute toxicity to saltwater aquatic_ life
occurs at concentrations as low as 0.79 mg/1. No data are
available concerning the chronic toxicity of this pollutant to
saltwater aquatic life.
For the protection of human health from the toxic properties^of
this pollutant, ingested through aquatic organisms alone, the
ambient water criterion is determined to be 14.1 mg/1.
With respect to treatment in *POTWs, laboratory studies have shown
that 1,3-dichloropropylene is only moderately amenable to
treatment via biochemical oxidation. The optimum expected 30-day
average treated effluent concentration for this pollutant is
0.100 mg/1.
2.4-dimethylphenol(34). 2,4-dimethylphenol (2,4-DMP), also
called 2,4-xylenol, is a colorless, crystalline^ solid at room
temperature (25oC), but melts at 27 to 28°C (81to82°F.
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 is a natural product, occurring in coal and petroleum
sources. It is used commercially as an intermediate for the
manufacture of pesticides, dyestuffs, plastics, resins, and
surfactants. It is found in the water runoff from asphalt
surfaces. It can find its way into the wastewater of a
manufacturing plant from any of several sources.
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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
dimethylphenols contain compounds which produced acute poisoning
in laboratory animals. Symptoms were difficult breathing, rapid
muscular spasms, disturbance of motor coordination, and
assymetrical 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 dimethylphenol, 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
Acute toxicity to freshwater aquatic life occurs at
2,4-dimethylphenol concentrations of 2.12 mg/1. For controlling
undesirable taste and odor quality of ambient water, due to the
organoleptic effects of 2,4-dimethylphenol in water, the
estimated level is 0.4 mg/1.
The behavior of 2,4-DMP in POTWs has not been studied. As a weak
acid its behavior may be somewhat dependent on the pH of the
i^J1,"61^ ,to the POTW> However, over the normal limited range of
POTW pH, little effect of pH would be expected.
Biological degradability of 2,4-DMP, as determined in one study
?™? 92'5 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
environment is low, thus any of the compound which remained in
the sludge or passed through the POTW into the effluent would be
degraded within a moderate length of time (estimated as 2 months
in the report).
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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 150,000 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 dyestuffs.
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
ambient water concentration is zero. Concentrations of
2,4-dinitrotoluene estimated to result in additional lifetime
cancer risk at risk levels of TO-7, 10-*, and 10~s are 0..0074
mg/1, 0.074 mg/1, and 0.740 mg/1, respectively.
Data on the behavior of 2,4-dinitrotoluene in POTWs are not
available. However, biochemical oxidation of 2,4-dinitrophenol
was investigated on a laboratory scale. At 100 mg/1 of
2,4-dinitrophenol, a concentration considerably higher than that
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 organic priority pollutants, it was
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concluded that biological treatment in POTWs removes
2,4-dinitrotoluene 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 amend soils in
which food crops are grown.
2,6-dinitrotoluene (36). 2, 6-dinitrotoluene [ (N02)2C
-------
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
constituent of xylene mixtures used as dilutents in the paint
industry, 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
carcinogenicity of ethylbenzene.
Criteria are based on data derived from inhalation exposure
limits. For the protection of human health from the toxic
properties of ethylbenzene, ingested through water and
contaminated aquatic organisms, the ambient water quality
criterion is 1.4 mg/1. If contaminated aquatic organisms alone
are consumed, excluding the consumption of water, the ambient
water criterion is 3.28 mg/1. Available data show that at
concentrations of 0.43 mg/1, adverse effects on aquatic life
occur.
The behavior of ethylbenzene in POTWs 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
observations relating molecular structure to ease of degradation,
it is expected that ethylbenzene will be biochemically oxidized
to a lesser extent than domestic sewage, by biological treatment
in POTWs.
An EPA study of seven POTWs showed removals of 77 to 100 percent
in five POTWs having influent ethyl benzene concentrations of 10
to 44 x 10~3 mg/1. The other two POTWs had influent
concentrations of 2 x 10~3 mg/1 or less. Other studies suggest
that most of the ethylbenzene entering a POTW is removed from the
aqueous stream to the sludge. The ethylbenzene contained in the
sludge removed from the POTW may volatilize.
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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 111°C (232°F)
and has a negligible vapor pressure at 25°C. Water solubility is
low (0.2 mg/1). Its molecular formula is C16H10.
Fluoranthene, along with many other PAHs, is found throughout the
environment. It is produced by pyrolytic processing of organic
raw materials, such as coal and petroleum, at high temperature
(coking processes). It occurs naturally as a product of plant
biosynthesis. 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 PAHs in at least one industrial effluent. Furthermore, 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 occured, no
information was reported concerning target organs or the specific
cause of death.
There is no epidemiological evidence to prove that PAHs 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
established procedure, the ambient water criterion for
fluoranthene, through water and contaminated aquatic organisms,
is determined to be 0.042 mg/1 for the protection of human health
from its toxic properties. If contaminated aquatic organisms
alone are consumed, excluding the consumption of water, the
ambient water criterion is 0.054 mg/1. Available data show that
adverse effects on aquatic life occur at concentrations of 0.016
mg/1.
Results of studies of the behavior of fluoranthene, in
conventional sewage treatment processes found in POTWs, 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 0.0435 mg/1 to a final" value of 0.00122 to 0.0146
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mg/1), and the removal was 91
0.00028 to 0.00026 mg/1) after
activated sludge processes.
to 99 percent (final values of
biological purification with
A review was made of data on biochemical oxidation of many of the
organic priority pollutants investigated in laboratory scale
studies at concentrations higher than would normally be expected
in municipal wastewater. 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
degradation 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
interference of fluoranthene with POTW operations, or the
persistence of fluoranthene in sludges on POTW effluent waters.
Several studies have documented the ubiquity of fluoranthene in
the environment, 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.
Bis(2-Ghloroethvoxv)methane (43). Bis(2-chloroethoxy) methane
[CH2(OCH2CH2Cirz1isacolorless liquid. It boils at 218.1°C
(424°F), flashes at 110°C (230°F), and has a vapor pressure of 1
mm Hg at 53°C. Slightly soluble in water, this chemical is
decomposed by mineral acids. This chemical is used as a solvent
and as an intermediate for polysulfide rubber.
The available data indicate that this pollutant is acutely toxic
to freshwater aquatic life at!concentrations as low as 0.36 mg/1,
and that chronictoxicity occurs at concentrations as low as
0.122 mg/1. No data are available to determine acute or chronic
toxicity levels for saltwater;aquatic life.
With respect to human health effects, a satisfactory criterion
cannot be derived at this time, due to the insufficiency in the
available data. T
Concerning treatment in POTWs, laboratory studies have shown that
this pollutant is only moderately amenable to treatment via
biochemical oxidation. It should be noted, however, that the
optimum estimated 30-day average treated effluent concentration
-311
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of 0.10 mg/1 is greater than the level at which this contaminant
was found in any foundry process wastewater.
Methylene chloride(44). Methylene chloride, also called
dichloromethane (CH2C12), 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
20PC), 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.
Methylene chloride is not generally regarded as being '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.
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 tests and
interpreting data results from the low boiling point (40°C) of
methylene chloride. This increases the difficulty of maintaining
the compound in growth media during incubation at 37°C. In
addition, it is difficult to remove 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 POTWs has not been studied
in any detail. 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 wastewaters. After five days, no degradation of
methylene chloride was observed. The conclusion reached is that
biological treatment produces litte or no removal by degradation
of methylene chloride in POTWs.
The high vapor pressure of methylene chloride is expected to
result in volatilization of the compound from aerobic treatment
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steps in POTWs. It has been reported that methylene chloride
inhibits anaerobic processes in POTWs. Any methylene chloride
that is not volatilized in the POTW is expected to pass through
into the effluent.
Methyl chloride (45). Methyl chloride (CH3C1) is a colorless,
noncorrosive liquifiable gas which is transparent in both the
gaseous and liquid states. It has a faintly sweet, ethereal
odor. It boils at -23.7°C (-11°F). It is slightly soluble in
water (by which it is decomposed) and soluble in alcohol,
chloroform, benzene, carbon tetrachloride, and glacial acetic
acid. It is derived by: (a) the chlorination of methane; and,
(b) the action of hydrochloric acid on methanol, either in vapor
or liquid phase. It is used as an extractant and solvent, as a
pesticide, in the synthesis of organic chemicals, and in
silicones.
The available data for this pollutant indicate that acute
toxicity to freshwater aquatic life occurs at concentrations as
low as 11.0 mg/1. No data are available concerning this
pollutant's chronic toxicity to sensitive freshwater aquatic
life. The available data for this pollutant indicate that acute
and chronic toxicities to saltwater aquatic life occur at
concentrations as low as 12.0 mg/1 and 6.40 mg/1 respectively.
With respect to saltwater aquatic life, a decrease in algal cell
numbers was found to occur at concentrations as low as 11.5 mg/1.
For the maximum protection of human health from the potential
carcinogenic effects due to exposure to this pollutant, through
the ingestion of contaminated water and aquatic organisms, the
ambient water concentration should be zero. Concentrations of
this pollutant estimated to result in additional lifetime cancer
risks at risk levels of 10-», 10-«, and 10~7 are 0.0019 mg/1,
0.00019 mg/1, and 0.000019 mg/1 respectively.
Concerning treatment in POTWs, laboratory studies have shown that
methyl chloride is not amenable to treatment via biochemical
oxidation. It should be noted that the optimum treated effluent
level of 0.100 mg/1 is greater than the levels ,at which this
pollutant was found in any foundry sampled.
Bromoform (47).' Brombform (CHBr3) is a colorless, heavy liquid
whose odor "and taste are similar to those of chloroform. It is
soluble in alcohol, ether, chloroform, benzene, solvent naphtha,
and fixed and volatile oils, while being only slightly soluble in
water. It melts at 9°C (48°F), boils at 151°C (304<>F) and has a
vapor pressure of 5 mm Hg of 22°C. This chemical is derived from
the heating of acetone or ethyl alcohol with bromine and alkali
hydroxide, with recovery by distillation. This product is used
313
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as an intermediate in organic synthesis
waxes, greases and oils.
and as a solvent for
Available freshwater data indicate that acute toxicity occurs at
concentrations as low as 11 mg/1 . No data are available
concerning chronic toxicity to sensitive freshwater aquatic life.
The available data indicate that acute and chronic toxicity to
saltwater aquatic life occur at concentrations as low as 12.0
mg/1 and 6.4 mg/1 respectively.
For the maximum protection of human health from the potential
carcinogenic effects due to exposure to bromoform, through
contaminated water and contaminated aquatic organisms, the
ambient water concentration should be zero. Concentrations of
this pollutant estimated to result in additional lifetime cancer
risk at risk levels of 10~5, 10~6, and 10~7 are 0.0019 mg/1,
0.00019 mg/1, and 0.000019 mg/1 respectively.
With respect to treatment in POTWs, laboratory studies have shown
that bromoform is not amenable to treatment incorporating
biochemical oxidation.
Dichlorobromomethane
colorless liquid which
data was available for this chemical.
an additive in certain organic synthesis processes.
Dichlorobromomethane (CHCl2Br) is a
boils at 90.1°C (194°F). No solubility
This chemical is used as
Available freshwater data indicate that acute toxicity occurs at
concentrations as low as 11 mg/1. No data are available
concerning chronic toxicity to sensitive freshwater aquatic life.
The available data indicate that acute and chronic toxicities to
saltwater aquatic life occur at concentrations as low as 12.0
mg/1 and 6.4 mg/1 respectively.
For the maximum protection of human health from the potential
carcinogenic effects due to exposure to dichlorobromomethane,
through contaminated water and contaminated aquatic organisms,
the ambient water concentration should be zero. Concentrations
of this pollutant estimated to result in additional lifetime
cancer risk at risk levels of 10~s, 10~6, and 1 0~7 are 0.0019
mg/1, 0.00019 mg/1, and 0.000019 mg/1 respectively.
With respect to treatment in POTWs, laboratory studies indicate
that this pollutant is not amenable to treatment via biochemical
oxidation.
Trichlorof luoromethane (49) .
Trichlorofluoromethane (CC13F) is a
nearly odorless, volatile liquid. It boils at 23.7°C
23.7°C. It is
colorless,
(75°F) and has a vapor pressure of 760 mm Hg at
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derived from the reaction of carbon tetrachlpride and hydrogen
fluoride in the presence of fluorinating agents such as antimony
tri- and penta-fluoride. It is used as a solvent and chemical
intermediate.
The available data for this pollutant indicate that acute
toxicity to freshwater aquatic life occurs at concentrations as
low as 11.0 mg/1. No data are available concerning this
pollutant's chronic toxicity to sensitive freshwater aquatic
life. The available data for this pollutant indicate that acute
and chronic toxicities to saltwater aquatic life occur at
concentrations as low as 12.0:mg/1 and6.40 mg/1 respectively.
With respect to saltwater aquatic life, a decrease in algal cell
numbers was found to occur at concentrations as low as 11.5 mg/1.
For the maximum protection of human health from the potential
carcinogenic, effects due to exposure to this pollutant, through
the ingestion of contaminated water and aquatic organisms, the
ambient water concentration: should be zero. Concentrations of
this pollutant estimated to result in additional lifetime cancer
risks at risk levels of 10-*, 10-*, and 10~7 are 0.0019 mg/1,
0.00019 mg/1, and 0.000019 mg/1 respectively.
With respect to treatment in POTWs, laboratory studies have
indicated that this pollutant is not amenable to treatment via
biochemical oxidation.
Chlorodibromomethane (51). Chlorodibromomethane (CHBr2Cl) is a
clear, colorless, heavy liquid. It boils at 116°C (24T°F). This
pollutant is used in the synthesis of various organic compounds.
The available data for this pollutant indicate that acute
toxicity to freshwater aquatic life occurs at concentrations as
low as 11.0 mg/1. No data are available concerning this
pollutant's chronic toxicity to sensitive freshwater aquatic
life. The available data for this pollutant indicate that acute
and chronic toxicities to saltwater aquatic life occur at
concentrations as low as 12.0 mg/1 and 6.40 mg/1 respectively.
With respect to saltwater aquatic life, a decrease in algal cell
numbers was found to occur at concentrations as low as 11.5 mg/1.
For the maximum protection of human health from the potential
carcinogenic effects due to exposure to this pollutant, through
the ingestion of contaminated water and aquatic organisms, the
ambient water concentration should be zero. Concentrations of
this pollutant estimated to result in additional lifetime cancer
risks at risk levels of 10~s, 10-«-, 10~7 are 0.0019 mg/1, 0.00019
mg/1, and 0.000019 mg/1 respectively.
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With respect to treatment in POTWs, laboratory studies indicate
that this pollutant is not amenable to treatment via biochemical
oxidation. It should be noted that the optimum expected treated
effluent level of 0.100 mg/1 for this pollutant is greater than
the level at which this pollutant was found in any foundry
sampled.
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-trimethy2-cyclo-hexene-l-
one and it is also known as trimethyl cyclohexanone and
isoacetophorone. The formula is C6H5(CH3)30. Normally, it is
produced as the gamma-isomer; technical grades contain about 3
percent of the beta-isomer (3,5-5-trimethyl-3-cyclohexen-l-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 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 co-solvent 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
laboratory animals in two different studies revealed no acute or
chronic effects during 90 days, and no hematological or
pathological 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
organisms reveal relatively low toxicity, compared to some other
priority pollutants.
The behavior of isophorone in POTWs has not been studied.
However, the biochemical oxidation of many of the organic
priority pollutants has been investigated in laboratory scale
studies at concentrations higher than would normally be expected
in municipal wastewater. General observations relating molecular
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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 treatment in POTWs 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
bio-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 CioHg.
As such, it is properly classed as a polynuclear aromatic
hydrocarbon (PAH). Pure naphthalene is a white crystalline solid
melting at 80°C (176°F).. 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)... Naphthalene 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
production is used as feedstock for phthalic anhydride
manufacture. Most of the remaining production goes into the
manufacture of insecticides, dyestuffs, pigments, and
Pharmaceuticals. Chlorinated 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
disease. 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.
The available data base is insufficient to establish an ambient
water criterion for the protection of human health from the toxic
properties of naphthalene. Available data show that adverse
effects in aquatic life occur at concentrations as low as 0.62
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
concentrations up to 22 »/g/l in studies carried out by the U.S.
EPA. Influent levels were not reported. The behavior of
naphthalene in POTWs has not been studied. However, recent
studies have determined that naphthalene will accumulate in
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sediments at TOO times the concentration in overlying water.
These results suggest that naphthalene will be readily removed by
primary and secondary settling in POTWs, if it is not
biologically degraded. ;
Biochemical oxidation of many of the organic priority pollutants
has been investigated in laboratory scale studies at
concentrations higher than would normally be expected in
municipal wastewater. 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 high removal by
degradation of naphthalene. One recent study has shown that
microorganisms can degrade naphthalene, first to a dihydro
compound, and ultimately to carbon dioxide and water.
Nitrobenzene (56). Nitrobenzene (C6H5N02), 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 (410°F) 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.
Almost the entire volume of nitrobenzene produced (97 percent) is
converted to aniline, which is used in dyes, rubber, and
medicinals. Other uses for nitrobenzene include: solvent for
organic synthesis, metal polish, 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;
paralysis; and death. Nitrobenzene has also exhibited
teratogenicity in laboratory animals, but studies conducted to
determine mutagenicity or carcinogenicity did not reveal either
of these properties.
For the prevention of adverse effects due to the organoleptic
properties of nitrobenzene in water, the criterion is 0.030 mg/1.
r
Data on the behavior of nitrobenzene in POTWs are not available.
However, laboratory scale studies have been conducted at
concentrations 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
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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 POTWs. The low water solubility and low
vapor pressure of nitrobenzene lead to the expectation that
nitrobenzene will be removed from POTWs in the effluent and by
volatilization during aerobic treatment.
2-nitrophenol (57). 2-nitrophenol (NOzCgH^OH) , also called
ortho-nitrophenol, is a light yellow crystalline solid,
manufactured commercially by hydrolysis of 2-chloro-nitrobenzene
with aqueous sodium hydroxide. 2-nitrophenol melts at 45°C
(113°F) 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 solvents. This phenol does not react to give
a color with 4-aminoantipyrene, and therefore does not contribute
to the non-conventional pollutant parameter "Total Phenols." U.S.
annual production is five thousand to eight thousand tons.
The principle use of ortho-nitrophenol is to synthesize
ortho-aminophenol, ortho-nitroanisole, and other dyestuff
intermediates.
The toxic effects of 2-nitrophenol on humans have not been
extensively 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. 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
2-nitrophenol do not reveal potential carcinogenic effects.
The available data base is insufficient to establish an ambient
water criterion for the 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 POTWs were not
available. However, laboratory scale studies have been conducted
at concentrations 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 on 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.
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4-nitrophenol (58). 4-nitrophenol (NO2C6H4OH), also called
para-nitrophenol, is a colorless to yellowish crystalline solid
manufactured commercially by hydrolysis of 4-chloro-nitrobenzene
with aqueous sodium hydroxide. 4-nitrophenol melts at 114<>C
(237°F). 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 non-conventional pollutant parameter "Total Phenols."
U.S. annual production is about 20/000 tons.
Para-nitrophenol is used to prepare phenetidine, aceta-phene-ti-
dine, azo and sulfur dyes, photochemicals, and pesticides.
The toxic effects of 4-nitrophenol on humans have not been
extensively studied. Data from experiments with laboratory
animals indicate that exposure to this compound results in
methemoglobinemia (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 certain 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 carcinogenic effects, although the compound has been
selected by the national cancer institute for testing under the
Carcinogenic Bioassay Program.
No U.S. standards for exposure to 4-nitrophenol in ambient water
have been established.
Data on the behavior of 4 nitrophenol in POTWs are not available.
However, laboratory scale studies have been conducted at
concentrations higher than those expected to be found in
municipal wastewater. Biochemical oxidation using adapated
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 expected that complete or nearly complete
removal of 4-nitrophenol occurs during biological treatment in
POTWs.
2,4-dinitrophenol (59). 2,4-dinitrophenol [(NO2)2C6H3OH], a
yellow crystalline solid, is manufactured commercially by
hydrolysis of 2,4-dinitro-l-chlorobenzene with sodium hydroxide.
2,4-dinitrophenol sublimes at 114°C (237°F). Vapor pressure is
not cited in usual sources. It is slightly soluble in water (7.9
g/1 at 25°C) and soluble in organic solvents. This phenol does
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not react with 4-aminoantipyrene and therefore does)( not
contribute to the non-conventional 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 are generally
attributed to this pollutant's ability to uncouple oxidative
phosphorylation. In brief, this means that sufficient
2,4-dinitrophenol short-circuits cell metabolism by preventing
utilization of energy provided by respiration and glycolosis.
Specific symptoms are gastrointestinal disturbances, weakness,
dizziness, headache, and loss of weight. More acute poisoning
includes symptoms such as: burning thirst, agitation, irregular"
breathing, 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-dinitrophenol 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-dinitrophenol does not possess carcinogenic
properties.
To protect human health from the adverse effects of
2,4-dinitrophenol, ingested in contaminated water and fish, the
suggested water quality criterion is 0.0686 mg/1.
Data on the behavior of 2,4-dinitrophenol in POTWs 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
expected that complete or nearly complete removal of
2,4-dinitrophenol occurs during biological treatment in POTWs..
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.
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DNOC is used primarily as a blossom thinning agent on fruit trees
and as a fungicide, insecticide and miticide on fruit trees
during the dormant season. It is highly toxic to plants in the
growing stage. DNOC is not manufactured in the U.S. as an
agricultural chemical. Imports of DNOC have been decreasing
recently with only 30,000 Ibs 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
agricultural pesticides. The available literature 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,
headache, malaise, and yellow staining to the skin, hair, sclera,
and conjunctiva.
There is no evidence to suggest that DNOC is teratogenic,
mutagenic, or carcinogenic. The effects of DNOC in the human due
to chronic exposure are basically the same as those effects
resulting from acute exposure. Although DNOC is considered a
cumulative 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
is determined to be 0.765 mg/1. No data are available concerning
the adverse effects of 4,6-dinitro-o-cresol on aquatic life.
Some studies have been reported regarding the behavior of DNOC in
POTWs. 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 destabilizing 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 POTWs.
N-nitrosodipheny1amine (62). N-nitrosodiphenylamine [(C«H5)2NNO],
also called nitrous diphenylamide, is a yellow crystalline solid
manufactured by nitrosation of diphenylamine. It melts at 66°C
(151°F) and is insoluble in water, but soluble in several organic
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solvents other than hydrocarbons. Production in the U.S. has
approached 1500 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-nitrosodiphenylamme
toxicity in adult rats lies in the midrange of the values for 60
N-nitroso compounds tested. Liver damage is the .principal toxic
effect. N-nitrosodiphenylamine, unlike many other
N-nitrosoamines, does not show mutagenic activity.
N-nitrosodiphenylamine has been reported by several
investigations to be non-carcinogenic. However, the compound is
capable of trans-nitrosation and could thereby convert other
amines to carcinogenic N-nitrosoamines. Sixty-seven of 87
N-nitrosoamines studied were reported to have carcinogenic
activity. No water quality criterion has been proposed for
N-nitrosodiphenylamine.
No data are available on the behavior of N-nitrosodiphenylamine
in POTWs. Biochemical oxidation of many of the organic priority
pollutants has been investigated, at .least in laboratory scale
studies, at concentrations higher than those expected to be
contained in most municipal wastewaters. General observations
have been developed relating molecular structure to ease of
degradation for all the organic priority pollutants. The
conclusion reached by study of. the limited data is that-
biological treatment produces little or no removal of
N-nitrosodiphenylamine in POTWs. No information is available
regarding possible interference by N-nitrosodiphenylamine in POTW
processes, or on the possible detrimental effects on sludge used
to amend soils in which crops are grown. However, no
interference or detrimental effects are expected, because
N-nitroso compounds are widely distributed in the soil and water-
environment, at low concentrations, as a result of microbial
action on nitrates and nitrosatable compounds.
N-nitrosodi-n-propvlamine (63). No physical properties or usage
data could be found for this pollutant. It can be formed from
the interaction of nitrite with secondary and tertiary amines.
The available data for this pollutant indicate that acute
toxicity to freshwater aquatic life occurs at concentrations as
low as 5.85 mg/1. No data are available concerning this
pollutant's chronic toxicity to freshwater and saltwater aquatic
life. The available data indicate that acute toxicity to
saltwater aquatic life occurs at concentrations as low as 3,300
mg/1. . ..- ••-- -• - •" • '"_'"•" ::'---' -'-. '"::'"r •" -•"-
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For the maximum protection of human health from the potential
carcinogenic effects due to exposure to this pollutant, through
the ingestion of contaminated water and aquatic organisms, the
ambient water concentration should be zero. Concentrations of
this pollutant estimated to result in additional lifetime cancer
risks at risk levels of 10-«, 10-«, and 10~7 are 0.00016 mg/1,
0.000016 mg/1, and 0.0000016 mg/1 respectively.
With respect to treatment in POTWs, laboratory studies indicate
that this pollutant is not amenable to treatment via biochemical
oxidation.
Pentachlorophenol(64). Pentachlorophenol (C6C15OH) 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 (374°F) and is
slightly soluble in water (14 mg/1). Pentachlorophenol is. not
detected by the 4-aminoantipyrene method.
Pentachlorophenol is a bactericide and fungicide and is used for
the 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
Pentachlorophenol, 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, experimental results and occupational exposure
observations must be examined carefully, to make sure that
observed effects are produced 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
pentachlorophenol does not accumulate in body tissues to any
significant extent. Studies on laboratory animals of
distribution of the compound in body tissues showed the highest
levels of pentachlorophenol 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 a pH of 6, where this weak acid is predominately in
the undissociated form than at a pH of 9, where the ionic form
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predominates. 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
carcinogenic effects of pentachlorophenol.
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 determined to be 1.01 mg/1. If contaminated aquatic
organisms alone are consumed, excluding the consumption of water,
the ambient water criterion is determined to be 29.4 mg/1.
Available data show that adverse effects on aquatic life occur at
concentrations as low as 0.0032 mg/1.
Only limited data are available for reaching conclusions about
the behavior of pentachlorophenol in POTWs. Pentachlorophenol
has been found in the influent to POTWs. In a study of one POTW,
the mean removal was 59 percent over a 7 day period. Trickling
filters removed 44 percent of the influent pentachlorophenol,
suggesting that biological degradation occurs. The same report
compared removal of pentachlorophenol at the same plant and two
additional POTWs 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 achieved 59 percent removal in the original study.
Influent 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 POTWs, Anaerobic digestion processes are
inhibited by 0.4 mg/1 of pentachlorophenol.
The low water solubility and low volatility of pentachlorophenol
lead to the expectation that most of the compund will remain in
the sludge in..a POTW. The effect on plants grown on land treated
with sludge containing pentachlorophenol is unpredictable.
Laboratory studies show that this compound affects crop
germination at 5.4 mg/1. However, photodecomposition of
pentachlorophenol 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 hydroxybenzerie and carbolic
acid, is a clear, colorless, hygroscopic, deliquescent,
crystalline solid at room temperature. Its melting point is 43°C
(109°F) and its vapor pressure at room temperature is 0.35 mm Hg.
325.
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It is very soluble in water (67 gm/1 at 16°C) and can be
dissolved in benzene, oils, and petroleum solids. Its formula is
CeHgOH.
Although a small percent of the annual production of phenol is
derived from coal tar as a naturally occuring product, most of
the phenol is synthesized. Two of the methods are fusion of
benzene 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
during the 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 Pharmaceuticals, and in the photo processing
industry. In this discussion, phenol is the specific compound
which is separated by methylene chloride extraction of an
acidified sample and identified and quantified by GC/MS. Phenol
also contributes to the pollutant "Total Phenols", discussed
elsewhere, which are determined by the 4-AAP colorimetric method.
Phenol exhibits acute and sub-acute toxicity in humans and
laboratory animals. Acute oral doses of phenol in humans cause
sudden collapse and unconsciousness due to the action of phenol
on the central nervous system. Death occurs by respiratory
arrest. Sub-acute oral doses in mammals are rapidly absorbed,
then quickly distributed to various organs, then cleared from the
body by urinary excretion and metabolism. Long term exposure, by
drinking phenol contaminated water, has resulted in statistically
significant increases 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 involved
skin tests.
For the protection of human health from phenol ingested through
water and through contaminated aquatic organisms, the ambient
water criterion is determined to be 3.5 mg/1. If contaminated
aquatic organisms alone are consumed, excluding the consumption
of water, the ambient water criterion is 769 mg/1. Available
data show that adverse effects in aquatic life occur at
concentrations as low as 2.56 mg/1.
Data have been developed on the behavior of phenol in POTWs.
Phenol is biodegradable by biota present in POTWs. The ability
of a POTW to treat phenol-bearing influents depends upon
acclimation of the biota and the constancy of the phenol
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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 through 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 POTWs, 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 thorugh the POTW
because of its very high water solubility. However in POTWs
whe?e ?hlorination isVacticed for disinfection of the POTW
effluent, chlorination of phenol may occur. The products of that
reaction may be priority pollutants.
The EPA has developed data on influent and effluent
concentrations of total phenols in a study of 103 POTWs.
Sowever the analytical procedure was the 4-AAP method mentioned
earlier and not the GC/MS method specif ically^ for phenol.
SlscuSs'ion of the study, which of course^ncludes phenol, is
presented under the pollutant heading "Total Phenols.
Phthalate Esters (66-71). Phthalic _ acid ,-omer?c"
1,2-benzenedicarboxylic acid, is one of three ifomer ic
benzenedicarboxylic acids produced by the chemical industry. The
otter So isomeric forms a?e called isophthalic and terephathalic
acids. The formula for all three acids is C«H* 5°OH)f' ,^°me
esters of phthalic acid are designated as priority ^"tants.
They will be discussed as a group here, and specif ic properties
of individual phthalate esters will be discussed afterwards.
Phthalic acid esters are manufactured in the U.S. at ah annual
rate in excess of 1 billion pounds. They are used as
DlaSticizers - primarily in the production of polyvinyl chloride
?P??) reSiSsY 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
Commonly referred to as dioctyl phthalate (DOP) ^ shouldnot^e
confused with one of the less used esters, di-n-octyl Palate
(69), which is also used as a plastcizer. In addition to these
two isomeric dioctyl phthalates, four .other esters, also used
primarily as plasticizers, are designated asjprionty Poljut^s.
They are: butyl benzyl phthalate (67), di-n-butyl phthalate (68),
diethyl phthalate (70), and dimethyl phthalate (71).
Industrially, phthalate esters are prepared from
anhydride and the specific alcohol to form the ester. Some
evidence is available suggesting that phthalic acid esters also
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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
concentrations 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
intermeshing 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 verv
slightly soluble in water, they do migrate into aqueous solutions
P-fuef "^.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
Xu4.u ?XE raw waste- In addition to their ,use as plasticizers
phthalate esters are used in lubricating oils and pesticid4
C^uX?r?' These also can contribute to industrial discharge of
phthalate esters.
From the accumulated data on acute toxicity in animals, phthalate
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 are most likely due to one of the
metabolic products,, in particular the monoester. Oral acute
toxicity in animals is greater for the lower molecular weiaht
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,
spleenitis, and degeneration of central nervous system tissue
Subacute doses administered orally to laboratory animals
some decrease in growth and degeneration of the testes.
studies in animals showed similar effects to those found
and subacute studies, but to a much lower degree.
organs were enlarged, but pathological changes were not
detected.
produced
Chronic
in acute
The same
usually
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 priority 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
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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 3 mg/1 in the freshwater crustacean
Daphnia maqna.. In acute toxicity studies, saltwater fish and
organisms~iho'wed 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 POTWs has "not been studied.
However, the biochemical oxidation of many of the organic
priority pollutants has been investigated in laboratory scale
studies at concentrations higher than would normally be expected
In municipal wastewater. , Three of the phthalate. esters were,
studied. 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. Based on these data and other
observations relating molecular structure to ease of biochemical
degradation of other organic pollutants, it is expected^that
butyl benzyl and dimethyl phthalate will be biochemically
oxidized to a lesser extent than domestic sewage by biological
treatment in a POTW. An EPA study of seven POTWs revealed that
for all but di-n-octyl phthalate, which was not studied, removals
ranged from 62 to 87 percent.
No informations was found on possible interference with POTW
operation 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 priority pollutant phthalate esters with water
solubilities 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
FiHarks and "discussion on phthalate esters, specific information
on bis (2-ethylhexyl) phthalate is provided. Little ^^mation
is available about the physical properties of bis(2-ethylhexyl)
phthalate. It is a liquid boiling at 387°C at 5mm Hg and is
insoluble in water. Its formula is C,H (COOC?H17)2-This
priority pollutant constitutes about one third of the phthalate
ester production in the U.S. It is commonly referred to as
dioctyl phthalate, or DOP, in the plastics industry, where it is
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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 priority
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
criterion is determined to be 15 mg/1. If contaminated aquatic
organisms alone are consumed, excluding the consumption of water
the ambient water criterion is determined to be 50 mg/1.
Although the behavior of bis(2-ethylhexyl) phthalate in POTWs has
not been studied, biochemical oxidation of -this priority
pollutant 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 oxidation 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 POTWs is expected.
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
phthalate.
butyl benzyl
. phthalate removal, by biological treatment in a
POTW, is expected to occur to a moderate degree.
Di-n-butvl phthalate (68). In addition to the general remarks
and discussion on phthalate esters, specific information on
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di-n-butyl phthalate (DBF) is provided. DBF.is a colorless, oily
liquid, boiling at 340°C. Its .water solubility at room
temperature is reported to : be 0.4 g/1 and 4.5 g/1 in two
different chemistry handbooks. The formula for
DBF, C6H4(COOC^H9)2 is the same as for its isomer, di-isobutyl
phthalate. DCP production is one to two 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 dilutent for
polysulfide dental impression materials. DBF is used as a
plasticizer 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
contaminated aquatic organisms, the ambient water quality
criterion is determined to be 34 mg/1. If contaminated aquatic-
organisms are consumed, excluding the consumption of water, the
ambient water criterion is 154 mg/1.
Although the behavior of di-n-butyl phthalate in POTWs has not
been studied, biochemical oxidation of this priority 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.
Based on these data, it is expected that di-n-butyl phthalate
will be biochemically oxidized to a lesser extent than domestic
sewage by biological treatment in POTWs. Biological treatment in
POTWs is expected to remove di-n-butyl phthalate to a moderate
degree.
Di-n-octvl 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
C6H4(COOC8H17)2. Its production constitutes about one percent of
all phthalate ester production in the U.S.
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Industrially, di-n-octyl phthalate
polyvinyl chloride (PVC) resins.
is used to plasticize
No ambient water quality criterion is proposed for di-n-octyl
phthalate. Biological treatment in 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
molecular formula is C6H4(COOC2H5)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
materials, 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 solutions, disinfectants, insecticides,
fungicides, and room deodorants which have ethyl alcohol as part
of the formulation. It is expected, therefore, that people and
buildings would have some surface loading of this priority
pollutant which would find its way into raw wastewaters.
For the protection of human health from the toxic properties of
diethyl phthalate, ingested through water and through
contaminated aquatic organisms, the ambient water quality
criterion is determined to be 350 mg/1. If contaminated aquatic
organisms alone are consumed, excluding the consumption of water,
the ambient water criterion is 1800 mg/1.
Although the behavior of diethyl phthalate in POTWs has not been
studied, biochemical oxidation of this priority pollutant has
been studied on a laboratory scale at concentrations higher than
would normally be expected in municipal wastewaters. Biochemical
oxidation of 79, 84, and 89 percent of theoretical was observed
after 5, 5, and 20 days, respectively. Based on these results,
it is expected that diethyl phthalate will be biochemically
oxidized to a lesser extent than domestic sewage by biological
treatment in POTWs.
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Dimethyl phthalate (71). In addition to the general remarks^and
discussion on pntnaiate esters, specific information on dimethyl
phthalate (DMP) is provided. BMP has the lowest molecular weight
of the phthalate esters - M.W. of 194 compared to M.W. of 391 for
bis(2-ethylhexyl)phthalate. DMP has a boiling point of 2820C.
It is a colorless liquid, soluble in water to the extent of 5
mg/1. Its molecular formula is C6H4(COOCH3)2.
Dimethyl phthalate production in the U.S. is just under one
percent of total phthalate ester production. DMP is used to some
extent as a plasticizer in cellulosics. However its principle
specific use is for dispersion of polyvinylidene fluoride (PVDF).
PVDF is resistant to most chemicals and finds use as electrical
insulation, chemical process equipment (particularly pipe), and
as a base 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
contaminated aquatic organisms, the ambient water quality
criterion is determined to be 313 mg/1. If contaminated aquatic
organisms alone are consumed, excluding the consumption of water,
the ambient water criterion is 2800 mg/1.
Based on limited data and observations relating molecular
structure to ease of biochemical degradation of other organic
pollutants, it is expected that dimethyl phthalate will be
biochemically oxidized to a lesser extent than domestic sewage by
biological treatment in POTWs.
Polvnuclear Aromatic Hydrocarbons(72-84). The polynuclear
aromatic hydrocarbons (PAH) selected as priority pollutants are a
group of 13 compounds consisting of substituted and unsubstituted
polycyclic aromatic rings. The general class of PAHs includes
heterocyclics, but none of those were selected as priority
pollutants. PAHs are formed as the result of incomplete
combustion when organic compounds are burned with insufficient
oxvqen. PAHs are found in coke oven emissions, vehicular
emissions, and volatile products of oil and gas burning. The
compounds chosen as priority pollutants are listed with their
structural formulas and melting points (m.p.). All are insoluble
in water.
72 Benzo(a)anthracene (1,2-benzanthracene)*
m.p. 162°C (324°F)
73 Benzo(a)pyrene (3,4-benzopyrene)*
; T'-~i m.p. '17.6DC (349°F)
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74 3,4-benzofluoranthene*
m.p. 168°C (334°F)
75 Benzo(k)fluoranthene (11,12-benzofluoranthene)
m.p. 217°C (391°F)
76 Chrysene (1,2-benzophenanthrene)*
77 Acenaphthylene*
HC=CH
78 Anthracene*
m.p. 255°C
m.p. 92°C (198°F)
m.p. 216°C (421°F)
HC=CH
79 Benzo(ghi)perylene (1,12-benzoperylene)
m.p. not reported
80 Fluorene (alpha-diphenylenemethane)*
81 Phenanthrene*
m.p. 116°C (241<>F)
m.p. 101°C (214°F)
82 Dibenzo(a,h)anthracene (1,2,5,6-dibenzoanthracene)
m.p. 269°C (516°F)
83 Indenod,2,3-cd)pyrene (2,3-o-phenylenepyrene)
m.p. not available
84 Pyrene*
m.p. 156°C (313°F)
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Note; An asterisk indicates that the pollutant is known to be present
in metal molding and casting process wastewaters.
Some of these priority pollutants have commercial or industrial
useL Benzo (a) anthracene, benzo(a)Pyrene, chrysene anthracene,
dibenzo(a,h)anthracene, and pyrene are all used a^ jntioxidants.
Chrysene, acenaphthylene, anthracene, fluorene, phenanthrene, and
pyrene are all used for synthesis of dyestuffs or other organic
chemicals. 3,4-benzof luoranthrene, benzo(k)f luoranthene, benzo
(qhi) perylene, and indeno (1,2,3-cd) pyrene have no known
industrial uses/ according to the results of a recent literature
search .
Several of the PAH priority pollutants are found in smoked^meats,
in smoke flavoring mixtures, in vegetable oils, and in coffee.
They are found in soils and sediments in river beds.
Consequently, they are also found in many drinking water
sSppliel The widedistribution of these pollutants in complex
mixtures, with the many other PAHs which have not b^n designated
as priority pollutants, results in exposures by humans that
cannot be associated with specific individual compounds.
The screening and verification analysis procedures used for the
organic priority pollutants are based on gas chromatography (GC) .
Three pairs of the PAHs have identical elution times on_the
columnipecified in the protocol, which means that the parameters
of the pair are not differentiated. For these three pairs
[anthracene (78) - phenanthrene (81); 3,4-benzof luoran thene (74^
- benzo(k)fluoranthene (75); and benzo (a) anthracene (72) ^
chrysene (76)] results are obtained and reported as either-or.
Either both are present in the combined concentration reported,
or one is present in the concentration reported. When detections
below reportable limits are recorded, ™f "r^V"3^3,1;3. ^
reauired For samples where the concentrations of coeluting
pairs have ..... I significant value, additional analyses are
Conducted, using different procedures that resolve the particular
pair.
There are no studies to document the possible carcinogenic risks
to humans by direct ingest ion. 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.b
dermal administration. The carcinogenicity of PAH has been
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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 exposure to polynuclear aromatic
hydrocarbons (PAH), through ingestion of water and contaminated
aquatic organisms, the ambient water concentration is zero
Concentrations of PAH estimated to result in additional lifetime
?an«Sr ^isk °f 10~7' 10~62' and 10~S are 2-8 x lO-^ mg/1, 2,8 x
10-' mg/1 and 2.8 x 1 o- mg/1 respectively. If contaminated
aquatic organisms alone are consumed, excluding the consumption
of water, the water concentration should be less than 3 11 x 10-*
mg/1 to keep the increased lifetime cancer risk below 10-s
Available data show the adverse effects on aquatic life occur at
concentrations higher than those cited for human health risk.
The behavior of PAHs in POTWs has received only a limited amount
of study. It is reported that up to 90 percent of the PAHs
entering a POTW will be retained in the sludge generated by
?°2?u"!:1unai Sewa9e treatment processes. Some of the PAHs can
inhibit bacterial 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
oxidation 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 organic priority pollutants, some general observations
were made relating molecular structure to ease of degradation.
Those observations lead to the conclusion that the 13 PAHs
selected to represent that^ group as priority pollutants, will be
removed only slightly or not at all by biological treatment
methods in POTWs. Based on their water insolubility and tendency
*£ ?n™o h0S?1Sedime"t Partifles, very little pass through of PAHs
to POTWs effluents is expected.
r?cent Agency study, Fate of Priority Pollutants in
Owned Treatment Works, the poI7uti[Ht~~c^ncentrations IK
the influent, effluent and sludge of 20 POTWs were measured. The
336
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results show that indeed the PAHs are concentrated -in.-the
sludges, and that little or no PAHs are discharged in the
effluent of POTWs. The differences in average concentrations
from influent to effluent range from 50 to . TOO percent removal
with all but one PAH above 80;percent removal. The data indicate
that all or nearly all of the , PAHs are concentrated in the
sludge.
No data are available at this time to support any conclusions
about PAH contamination of land on which sewage sludge containing
PAH is spread. .
Tetrachloroethvlene(85). Tetrachloroethylene (CCl.2CClz), also
called perchloroethylene and PCE, is a colorless nonflammable
liquid produced mainly by two methods - chlonnation and
pyrolysis of ethane and propane, and oxychlorination of
dichloroethane. U.S. annual production exceeds 300,000 tons.
PCE boils at 121°C (250°F) and has a vapor pressure of 19 mm Hg
at 20°C. It is insoluble in water but soluble in organic
solvents.
Approximately two-thirds of'the U.S. production pf 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
concentration. High integrated exposure (concentration times
duration) produces kidney and liver damage. Very limited data on
PCE ingested by laboratory animals indicate that 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
conclude, that PCE is teratogenic. PCE has been demonstrated to
be a liver carcinogen in B6C3F1 mice.
For the maximum protection of human health from the potential
carcinogenic effects of exposure to tetrachloroethylene, through
ingestion of water and contaminated aquatic organisms, the
ambient water concentration is zero. Concentrations of
tetrachloroethylene estimated to result in additional lifetime
cancer risk levels of TO-7, 10-«, and 10-* are 8 x 10-s mg/1, 8 x
10-* mg/1, 8 x 10-3mg/l respectively. If contaminated aquatic
organisms alone are consumed, excluding the consumption of water,
the water concentration should be less than 0.088 mg/1 to keep
the increased lifetime cancer risk below 10~». Available data
:: -337
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show that adverse effects on aquatic life occur at concentrations
higher than those cited for human health risks.
No data were found regarding the behavior of PCE in POTWs. Many
of the organic priority 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 organic priority
K 1U »r*S' -?fSud u" Study of the limited data, it is expected
that PCE will be biochemically oxidized to a lesser extent than
domestic sewage by biological treatment in POTWs. An EPA studv
of seven POTWs revealed removals of 40 to 100 percent. Sludqe
concentrations of tetrachloroethylene ranged from 1 x 10-3 to 16
mg/1. 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 occuring 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 phenymethane. It is an aromatic hydrocarbon with the formul4
LgH5CH3. It boils at llioc and has a vapor pressure of 30 mm Hq
at room temperature. The water solubility of toluene is 535
TSm.ai x, 1J- 1S "Jscible with a variety of organic solvents.
Annual production of toluene in the U.S. is greater than 2
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 annually as a
constituent in wastewater. ,
Most data on the effects of toluene in humans 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
morphology of major organs. The effects of inhaled toluene on
the central nervous system, both at high and low concentrations
have been studied in humans and animals. However, inaested
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
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principal metabolic products- 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 iH 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
have been calculated on the basis of the octanol-water partition
coefficient.
For the
toluene, i
organisms,
mg/1. If
excluding
criterion
on aquatic
protection of human health from the toxic properties of
ngested through water and through contaminated aquatic
the ambient water criterion is determined to be 14.3
contaminated aquatic organisms alone are consumed,
the consumption of water, the ambient water quality
is 424 mg/1. Available data show that adverse affects
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 maqna. 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.
Only one study of toluene behavior in POTWs is available.
However, the biochemical oxidation of many of the priority
pollutants has been investigated in laboratory scale studies at
concentrations centrations greater than those expected to be
contained by most municipal wastewaters. At toluene
concentrations ranging from 3 to 25.0 mg/1, biochemical oxidation
proceeded to fifty 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 expectation that aeration processes will remove
significant quantities of toluene from the POTW. The EPA studied
toluene removal in seven POTWs. The removals ranged from 40 to
100 percent. Sludge concentrations of toluene ranged from 54 x
10-3 to 1.85 mg/1.
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Trichloroethvlene(87). Trichloroethylene (1,1,2-trichlor-
ethylene or TCE) is a clear colorless boiling at 87°C (189°F).
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
tetrachloroethane by treatment with lime in the presence of
water.
TCE 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.
Data on the effects produced by ingested TCE are limited. Most
studies have been directed at inhalation exposure. Nervous
system 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 anesthetic
before its other long term effects were defined.
TCE has been shown to induce transformation in a highly sensitive
iH 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,
exposure 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
concentration is zero. Concentrations of trichloroethylene
estimated to result in additional lifetime cancer risk of 1 in
100,000 corresponds to an ambient water concentration of 0.00021
mg/1.
Only a very limited amount of data on the effects of TCE on
freshwater aquatic life are available. One species of fish
(fathead minnows) showed a loss of equilibrium at concentrations
below those resulting in lethal effects. The limited data for
aquatic life show that adverse effects occur at concentrations
higher than those cited for human health risks.
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For a recent Agency study, Fate of Priority Pollutants in.
Publicly Owned Treatment Works, the pollutant concentrations in
the influent, effluent, and sludge of 20 POTWs were measured. No
conclusions were made; however, trichloroethylene appeared in 95
percent of the influent stream samples but only in 54 percent of
the effluent stream samples. This indicates that
trichloroethylene either is concentrated in the sludge or escapes
to the atmosphere. Concentration? in 5.0 percent of the sludge
samples indicate that much of the trichloroethylene is
concentrated there.
Aldrin (89). Aldrin (C12H8C16) is a brown to white crystalline
solid whTcV is used as an insecticide. It melts at -104-1 05.5°C
(219-222°F). While soluble in most organic solvents, aldrin is
insoluble in water. It is not affected by alkalies or dilute
acids, and is compatible with most herbicides, fertilizers,,
fungicides, and insecticides.
For freshwater aquatic life, the concentration of aldrin should
not exceed 0.003 mg/1. For saltwater aquatic life, the
concentration of this pollutant should not exceed 0.0013 mg/1 at
any time. No data are available concerning this pollutant's
chronic toxicity.
For the maximum protection of human health from the potential
carcinogenic effects of exposure to this pollutant, through the
ingestion of contaminated water and aquatic organisms, the
ambient water concentration should be zero. Concentrations, of
this pollutant estimated to result in additional lifetime cancer
risks at risk levels of 10-5, 10-*, and TO-7 are 0.00000074 mg/1,
0.000000074 mg/1, and 0.0000000074 mg/1 respectively. . ,
With respect to discharges to a POTW, it must be noted that this
pollutant is toxic to biological organisms. As this pollutant
can interfere with the biological treatment processes in a POTW,
its discharge to a POTW must be carefully controlled.
Chlordane (91_). Chlordane (C10H6C18) is a colorless, odorless,
viscous liquid." It boils at 175°C (347°F) and. decomposes in weak
alkalies. This chemical is soluble in many organic solvents,
insoluble in water, and miscible in deodorized kerosene. In
addition to its use as an insecticide, this chemical is also used
in oil emulsions and dispersible liquids.
The criterion to protect freshwater aquatic life is 0.0000043
mg/1 as a 24 hour average and the concentration should not exceed
0.0024 mg/1 at any time. The criterion to protect saltwater
aquatic life is 0.000004 mg/1 as a 24 hour average and the
concentration should not exceed 0.00009 mg/1 at any time.
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For the maximum protection of human health from the potential
carcinogenic effects due to exposure to chlordane, through the
ingestion of contaminated water and contaminated aquatic
organisms, the ambient water concentration should be zero.
Concentrations of this pollutant estimated to result in
additional lifetime cancer risk at risk levels of TO"5, TO"6/ and
1077 are 0.0000046 mg/1, 0.00000046 mg/1, and 0.000000046 mg/1
respectively.
With respect to treatment in POTWs, this substance is
biodegradable, but can also accumulate in biological organisms
and exert a toxic effect. Therefore, the discharge of this
pollutant to a POTW must be carefully controlled to avoid
inhibitory effects on the POTW treatment process.
4,4'-DDT(92). 4,4'-DDT (C1C€H4)2CHCC13 is a colorless crystal or
a slightly off-white powder which is odorless or slightly
aromatic. It is soluble in acetone, ether, benzene, carbon
tetrachloride, kerosene, dioxane, and pyridine, but insoluble in
water. It is not compatible with alkaline materials. This
compound is derived by condensing chloral or chloral hydrate with
chlorobenzene in the presence of fuming sulfuric acid. It is
used as an insecticide.
For this pollutant, the criterion to protect freshwater and
saltwater aquatic life is 0.0000010 mg/1 as a 24 hour average.
The concentrations which should not be exceeded at any time are
0.0011 mg/1 for fresh waters and 0.00013 mg/1 for saltwaters.
For the maximum protection of human health from the potential
carcinogenic effects due to exposure to this pollutant, through
the ingestion of contaminated water and aquatic organisms, the
ambient water concentrations should be zero. Concentrations of
this pollutant estimated to result in additional lifetime cancer
risks at risk levels of 10-5, 10~6, and 10~7 are 0.00000024 mg/1,
0.000000024 mg/1, and 0.0000000024 mg/1 respectively.
With respect to discharge to a POTW, it must be noted that this
pollutant is toxic to biological organisms. As this pollutant
can interfere with the biological treatment process in a POTW,
its discharge to a POTW must be carefully controlled.
4,4'-DDE (93). 4,4'-DDE (C1C6H4)2 CHCC13 is a colorless crystal
or slightly off-white powder which is odorless or exhibits a
slight aromatic odor. It is soluble in acetone, ether, benzene,
carbon tetrachloride, kerosene, dioxane, and pyridine but is
insoluble in water. It is not compatible with alkaline
materials. This pollutant is derived by condensing chloral or
342
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chloral hydrate with chlorobenzene in the presence of fuming
sulfuric acid. It is used as a pesticide.
For this pollutant/ 'the criterion to protect freshwater • and
saltwater aquatic life is 0.0000010 mg/1 as a 24-hour average.
The concentrations which should not be exceeded at any time are
0.0011 mg/1 for freshwaters and 0.00013 mg/1 for saltwaters.
For the maximum protection of human health from the potential
carcinogenic effects due to exposure to this pollutant, through
the ingestion of contaminated water and aquatic organisms, the
ambient water concentration should be zero. Concentrations of
this pollutant estimated to result in additional lifetime cancer
risks at risk levels of 10~s, TO-*/ and 10~7 are 0.00000024 mg/1,
0.000000024 mg/1, and 0.0000000027 mg/1 respectively.
With respect to discharges to,a POTW, it must be noted that this
pollutant is toxic to biological organisms. As this pollutant
can interfere with the biological treatment processes in a POTW,
its discharge, to a POTW must be carefully controlled.
Endrin Aldehyde (99). Endrin aldehyde is a biodegradation
product of endirin. While known to be toxic no additional data
pertaining to aquatic toxicity, ambient water quality criteria,
and cancer risk levels are available.
Heptachlor epoxide (101). Heptachlor epoxide (C10H9C170) is a
degradation product of heptachlor and subsequently also acts as
an insecticide.
The criteria to protect fresh water and saltwater aquatic life
are 0.0000053 mg/1 and 0.0000050 mg/1 respectively. The
concentrations which should not be exceeded at any time are
0.00052 mg/1 for freshwaters and 0,0000053 mg/1 for saltwaters.
For the maximum protection of human health from the potential
carcinogenic effects due to exposure to this pollutant, through
the ingestion of contaminated water and aquatic organisms, the
ambient water concentration should be zero. Concentrations of
this pollutant estimated to result in additional lifetime cancer
risks at risk levels of 10~s, 10~«, and 10~7 are 0.00000278 mg/1,
0.000000278 mg/1, and 0.0000000278 mg/1 respectively.
With respect to discharge to a POTW, it must be noted that this
pollutant is toxic to biological organisms. As this pollutant
can interfere with the biological treatment processes in a POTW,
its discharge to a POTW must be carefully controlled.
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Hexachlorocyclohexanes (102, 103, 104 and 105). The alpha, beta,
gamma, and delta BHC isomers (C«H6C16) are white, crystalline
powders with slightly musty odors. These isomers melt at about
"M2°C (234°F) and are: freely soluble in acetone, benzene and
chloroform; soluble in alcohol; slightly soluble in ethylene
glycol; and practically insoluble in water. These products are
derived from the chlorination of benzene in the presence of
ultraviolet light. The mixture of stereoisomers is separated by
fractional crystallization. These isomers are used as
insecticides.
The available data for a mixture of isomers of BHC indicate that
acute toxicity to freshwater aquatic life occurs at
concentrations as low as 0.1 mg/1 and would occur at lower
concentrations among species more sensitive than those tested.
The available data for a mixture of BHC isomers indicate that
acute toxicity to saltwater aquatic life occurs at concentrations
as low as 0.00034 mg/1. No data are available concerning chronic
toxicity to freshwater or saltwater species.
For maximum protection of human health from the potential
carcinogenic effects due to exposure to the BHC isomers, through
the ingestion of contaminated waters and contaminated aquatic
organisms, the ambient water concentrations for alpha and beta
BHC should be zero. Using the present guidelines, a satisfactory
criterion for delta BHC cannot be derived at this time, due to an
insufficiency of data. Concentrations estimated to result in
additional lifetime cancer risk at risk levels of 1 0~5 10~6, and
10~7 are 0.000092 mg/1, 0.0000092 mg/1, and 0.00000092 mg/1 for
alpha BHC, and 0.000163 mg/1, 0.0000163 mg/1, and 0.00000163 mg/1
for beta BHC. For the protection of human health from the
ingestion of contaminated water and aquatic organisms, the
ambient water criterion for gamma BHt is determined to be
0.000625 mg/1. At this time, a satisfactory criterion for delta
BHC cannot be derived.
With respect to the acceptability of these pollutants to POTWs,
it must be noted that they are pesticides and therefore toxic to
the biological organisms which accomplish treatment in POTWs.
Subsequently, the discharge of these substances to POTWs must be
controlled.
Polychlorinated biphenyls (106-112). Polychlorinated biphenyls
(C12Hi0nCln,H,0-nCln where n can range from 1 to 10), designated
PCB's, are chlorinated derivatives of biphenyls. The commerical
products are complex mixtures of chlorobiphenyls, but are no
longer produced in the U.S. The mixtures produced formerly were
characterized by the percentage chlorination. Direct
chlorination of biphenyl was used to produce mixtures containing
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from 21 to 70 percent chlorine.
selected as priority pollutants;
Six of these mixtures have been
Priority
Pollutant
Number Name
Percent Distillation Pour 25°C Water
Chlorine Range(°C) Point(°C) Solubility ,/g/l
106
107
108
109
110
111
112
PCB
PCB
PCB
PCB
PCB
PCB
PCB
1
1
1
1
1
1
1
242
254
221
232
248
260
016
20.
31 .
42
54
5-21 .
4-32.
48
60
41
5
5
325-366
365-390
275-320
290-325
340-375
385-420
323-356
-19
10
1
-35,
-7
31
240
12
>200 .
54
2.7
225-250
The PCBs 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 PCBs averaged about
20,000 tons in 1972-1974.
Prior to 1971, PCBs were used in several applications including
plasticizers, heat transfer liquids, hydraulic fluids,
lubricants, 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 PCBs 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 (PCDFs)
are found in many commercial PCB mixtures. Photochemical and
thermal decomposition appear to accelerate the transformation of
PCBs to PCDFs. Thus the specific effects of PCBs may be masked
by the effects of PCDFs. However, if PCDFs are frequently
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 PCBs 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 PCBs 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 PCBs 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.
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For the maximum protection of human health from the potential
carcinogenic effects of exposure to PCBs, through ingestion of
water and contaminated aquatic organisms, the ambient water
concentration should be zero. Concentrations of PCBs estimated
to result in additional lifetime cancer risk at risk levels of
10-*, TO-6, and 10~5 are 0.0000000026 mg/1, 0.000000026 mg/1, and
0.00000026 mg/1, respectively.
The behavior of PCBs in POTWs has received limited study. Most
PCBs will be removed with sludge. One study showed removals of
82 to 89 percent, depending on suspended solid removal. The PCBs
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
more toxic than PCBs (as noted earlier). PCBs at concentrations
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 PCBs. Based
on studies of bioaccumulation of PCBs 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 (chemical name - stibium, symbol Sb)
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 nonmetal products. A principal compound is antimony trioxide
which is used as a flame retardant in fabrics, and as an
opacifier in glass, ceramics, and enamels. Several antimony
compounds are used as catalysts in organic chemicals synthesis,
as fluorinating agents (the antimony fluoride), as pigments, and
in fireworks. 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
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antimonial compounds, usually used to treat schistosomiasis, 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 alone are consumed,
excluding the consumption of water, the ambient water criterion
is determined 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, POTWs. The limited solubilities of most antimony
compounds expected in POTWs, i.e. the oxides and sulfides,
suggest 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 croplands.
Arsenic(115). Arsenic (chemical symbol As), 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 6T5°G (1139°F). 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 _ arsenicis in agricultural chemicals
(herbicides) for controlling weeds in cotton fields. , Arsenicals
have various applications in medicinal and veterinary 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
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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 a hundred
years. Since 1888, numerous studies have linked occupational
exposure to, 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
concentration is zero. Concentrations of arsenic estimated to
result in additional lifetime cancer risk levels of 10~7, 10~*,
and 10-5 are 2.2 x 10-*° mg/1, 2.2 x lO-» mg/1, and 2.2 x 10-«
mg/1, respectively. If contaminated aquatic organisms alone are
consumed, excluding the consumption of water, the water
concentration should be less than 2.7 x 10~4 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.
A few studies have been made regarding the behavior of arsenic in
POTWs. One EPA survey of 9 POTWs reported influent
concentrations ranging from 0.0005 to 0.693 mg/1; effluents from
3 POTWs having biological treatment contained 0.0004 - 0.01 mg/1;
2 POTWs showed arsenic removal efficiencies of 50 and 71 percent
in biological treatment. Inhibition 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 POTWs, 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.
Beryl1jump 17). 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,
especially 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
operations. Analysis of coal indicates an average beryllium
content of 3 ppm and 0.1 to 1.0 percent in coal ash or fly ash.
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The principal ores are beryl (3BeO»Al2Os»6Si02) and bertrandite
[Be4Si2O7(OH)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 (1350°C). Beryllium alloys are
corrosion resistant, but the metal corrodes in aqueous
environments. Most"T:ommohberyllium 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.
However, a recently convened panel of uninvolved experts
concluded that epidemiologic evidence is suggestive that
beryllium is a carcinogen in man.
In the aquatic3environment, beryllium is acutely toxic to fish at
concentrations as low as 0.087 mg/1, and chronically toxic to an
aquatic organism at 0.003 mg/1. Water softness has a large
effect on beryllium toxicity to fish. In soft water, beryllium
is reportedly TOO 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 TO-7, 10~«,
and TO-5 are 0.00000087 mg/1, 0.0000087 mg/1, and 0.000087 mg/1,
respectively.
Information on the behavior of beryllium in POTWs is scarce.
Because beryllium hydroxide is insoluble in water, most beryllium
entering POTWs 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.
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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
production.
Cadmium is used primarily as an electroplated metal, and is found
as an impurity in the secondary refining of zinc, lead, and
copper. Cadmium appears at a significant level in raw
wastewaters from only one of the three subcategories of coil
coating - galvanized. The presence of cadmium in the wastewater
is attributed to its presence as an impurity in the zinc used to
produce galvanized coil stock. Some of the zinc is removed by
the cleaning and conversion coating steps.
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
throughout 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. A severe bone and kidney syndrome known as
itai-itai disease has been documented in Japan as being caused by
cadmium ingestion via drinking water and contaminated irrigation
water. Ingestion of as little as 0.6 ing/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 1000 for cadmium in fish
muscle has been reported as having concentration factors of 3000
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 0.01.0
mg/1. Available data show that adverse effects on aquatic life
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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
in the POTW sludge. In addition, it can interfere with the POTW
treatment process.
In a study of 189 POTWs, 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 2 of the 189 POTWs 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 standard deviation 0.167).
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 mg/kg
cadmium, 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 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*Cr203). 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 (Na?CrO4), and chromic acid (CrO3) - both are
hexavalent chromium compounds.
Chromium and its compounds are used extensively in the coil
coating industry. As the metal, it is found as an alloying
component of many steels.
The two chromium forms most frequently found in industry
wastewaters are hexavalent and trivalent chromium. Hexavalent
chromium is the form used for metal treatments. Some of it is
reduced to trivalent chromium as part of the process reaction.
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The raw wastewater containing both valence states is usually
treated first to reduce remaining hexavalent to trivalent
chromium, and second to precipitate the trivalent form as the
hydroxide. 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
sensitizfations. 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 chromate ions that show no effect in man appear to be
so low as to prohibit determination, to date.
i
The toxicity of chromium salts to fish and other aquatic lif-e
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 recommended water quality
criterion is 0.050 mg/1.
For the maximum protection of human health from the potential
carcinogenic effects of exposure to hexavalent chromium, through
ingestion of water and contaminated aquatic organisms, the
ambient water concentration is zero. The estimated levels which
would result in increased lifetime cancer risks of 10~7, 10-*,
and 10-s are 7.4 x IO-« mg/1, 7.4 x 10~7 mg/1, and 7.4 x 10-*
mg/1 respectively. If contaminated aquatic organisms alone are
consumed, excluding the consumption of water, the water
concentration should be less than 1.5 x 10~5 mg/1 to keep the
increased lifetime cancer risk below 10~5.
Chromium is not destroyed when treated by POTWs (although the
oxidation state may change), and will either pass through to the
POTW effluent or be incorporated into the POTW sludge. Both
oxidation 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
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chromium 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
nitrification 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 trivalent chromium has little or no toxicity to
activated sludge, except at high concentrations. The presence or
iron, copper, and low pH will increase the toxicity of chromium
in a POTW by releasing the chromium into solution to be ingested
by microorganisms 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. v In
a study of 240 POTWs 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
problems in uncontrollable landfills. Incineration, or similar
destructive oxidation processes can produce hexavalent chromium
from lower valance 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
concentration of chromium in sludge. In Buffalo, New York,
pretreatment of electroplating waste resulted in a decrease in
chromium concentrations in POTW sludges from 2,510 to
1,040 mg/kg. A similar reduction occurred in Grand Rapids,
Michigan POTWs, 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
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such as cuprite (Cu20), malachite [CuC03»Cu(OH)2], azurite
[2CuC03»Cu(OH)2], chalcopyrite (CuFeS2), and bornite (CusFeS4).
Copper is obtained from these ores by smelting, leaching, and
electrolysis. It is used in the plating, electrical, 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
irritations, at relatively low dosages.
domestic water supplies is taste.
The limiting factor in
To prevent this adverse
organoleptic 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
chemical characteristics of the water, including temperature,
hardness, 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 0.031 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 saltwater aquatic life is
0.00097 mg/1 as a 24-hour average, and 0.018 mg/1 maximum
concentration.
Copper salts cause undesirable color reactions in the food
industry and cause pitting when deposited on some other metals
such as aluminum and galvanized steel.
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
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up to high levels when toxicity occurs. For example, the
concentrations of copper in snapbean leaves and pods were less
than 50 and 20 mg/kg, respectively, under conditions of severe
copper toxicity. 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 POTW facilities has been
observed by the EPA to range from 0.01 to 1.97 mg/1, with a
median concentration of 0.12 mg/1. The copper that is removed
from the influent stream of a POTW is adsorbed on the sludge or
appears in the sludge as the hydroxide of the metal. Bench scale
pilot studies have shown that 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 unacclimated
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 POTWs, 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 usually range from 18 to 80 mg/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 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 that a reversion of copper to less soluble forms was
occurring.
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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
complexes. 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
complexes is extremely variable. Those formed with zinc, copper,
and cadmium are not stable - they rapidly dissociate, with
production of HCN, in near neutral or acid waters. Some of the
complexes 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.
Cyanides are more toxic to fish than to lower forms of aquatic
organisms such as midge larvae, crustaceans, and mussels.
Toxicity 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 0.15 mg/1 have been proven to be fatal to sensitive fish
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species including trout, bl.uegi.il/ 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 t,p 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. Available data show that effects on aquatic life
occur at concentrations as low as 3.5 x 10-3 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
complete 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 preparation.
Cyanides can interfere with treatment processes in POTWs, or pass
through to ambient waters. At low concentrations, and with
acclimated microflora, cyanide may be "decomposed by
microorganisms in anaerobic and aerobic environments or waste
treatment systems. However, data indicate that much of the
cyanide introduced passes through to the POTW effluent. The mean
pass through of 14 biological plants was 71 percent. In a recent
study of 41 POTWs 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 priority pollutants cadmium, zinc, and
copper.
Data for Grand Rapids, Michigan, showed a significant decline in
cyanide concentrations downstream from the POTW after
pretreatment regulations were enforced. 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,
metallicelement, usually obtained from the mineral galena (lead
sulfide, PbS), anglesite (lead sulfate, PbS04), or cerussite
(lead carbonate,, PbC03). Because it is usually associated with
minerals of zinc, silver, copper, gold, cadmium, antimony, and
arsenic, special purification methods are frequently used before
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and after extraction of the metal from
smelting.
the ore concentrate by
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 metals 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
experimental animals. Mutagenicity data are not available for
1 ead.
For the protection of human health from the toxic properties of
lead, ingested through water and contaminated aquatic organisms,
the ambient water criterion is 0.050 mg/1. Available data show
that adverse effects on aquatic life occur at concentrations as
low as 7.5 x 10~4 mg/1.
Lead is not destroyed in POTWs, 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
concentration 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 POTWs, 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
concentrations in POTW effluents ranged from 0.003 to' 1.8 mg/1
(mean » 0.106 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 conditions
of low pH (less than 5.5) and low concentrations of labile
phosphorus, lead solubility is increased and plants can
accumulate lead.
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Mercury (123). Mercury is an elemental metal Barely
nature aTThe free metal. Mercury is unique among metals, as j.t .
remains a liquid down to about -39°C. It is^ relatively inert
chemically and is insoluble in water. The principal ore is
cinnabar (Hgj5) .
Mercury is used industrially as the metal and as mercurous and
mlrcuric salts and compounds. 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
gastrointestinal tract. Fatal doses can vary from '^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 TOO times the
concentration in the surrounding sea water, are eaten by f ish,
which further concentrates 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
mg/1 .
Mercury is not destroyed when treated by a POTW, and will either
oass through to the POTW effluent or be incorporated into the
POTW slSdge At low concentrations, it may reduce POTW removal
efficiencies, and at high concentrations, it may upset the POTW
operation.
The influent concentrations of "v mercury to POTWs have been
oblervSd by the EPA to range from 0.0002 to 0. 24 mg/1, with a
melian concentration of 0.001 mg/1. Mercury has been reported^n
the literature to have inhibiting effects upon an activated
IS
inhibitory effects being reported at 1365 mg/1
359.
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In a study of 22 POTWs 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.
T.he mercury content of soils not receiving additions of POTW
sewage sludge lies 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 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
elemental metal. It is a relatively plentiful element a.nd 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)9Sa], and a
lateritic ore consisting of hydrated nickel-iron-magnesium
silicate.
Nickel has many varied uses. It is used in alloys and as the
pure metal. Nickel salts are used for electroplating baths.
t
The toxicity of nickel to man is thought to be very low and
systemic 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 hiqh
incidence of cancer of the lung and nose has been reported in
humans engaged in the refining of nickel.
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Nickel salts can kill fish at very low concentrations. However,
s
animals contain up to 0.4 mg/1 and marine plants contain up to
Trng/l 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 from the toxic properties _ of
nickel ingested through water and through contaminated aquatic
Srgan sms the ambient water criterion is determined to be 0 34
mg/1. If contaminated aquatic organisms are consumed excluding
consumption of water, the ambient water criterion is determined
to be 1 01 mg/1. Available data show that adverse effects on
aquatfc life occur for total recoverable nickel concentrations as
low as 0.032 mg/1.
Nickel is not destroyed when treated in a POTW, but will either
oass through to the POTW effluent or be retained in the POTW
SlSdge? 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
sianif icantly reduced normal treatment efficiencies for a few
houri but the plant acclimated itself somewhat to the slug
do^e and appeared to achieve norma ^treatment e «-iencies
within 40 hours. It has been reported that the anaerobic
diges?ion process is inhibited only by high concentrations of
nickel, while a low concentration of nickel inhibits the
nitrification process. .^r .... - -. •-
The influent concentration of nickel to POTW facilities has. been
observed by the EPA to range from 0.01 to 3.19 mg/1, with a
median of 033 mg/1. In a study of 190 POTWs, nickel pass
through was greate? than 90 percent for 82 percent of the primary
plants. Median pass through for trickling filter, activated
lludge, 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. !n-S 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.
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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 TOO mg/kg. Various
environmental exposures to nickel appear to correlate with
increased incidence of tumors in man. For example, cancer in the
maxillary antrum of snuff users may result from using plant
material 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.
I? ?n« 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,
T°xicit* of nickel to plants L
Selenium(125). Selenium (chemical symbol Se) is a non-metallic
SJ®m^nu existin9 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
or 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 ingest ion of a larger
dose of selenium acid, peripheral vascular collapse, pulumonary
edema, and coma occurred. Selenium produces mutagenic and
teratogenic effects, but it has not been established as
exhibiting carcinogenic activity.
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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
ma/1 Available data show that adverse effects on aquatic life
occur at concentrations higher than that cited for human
toxicity.
Very few data are available regarding the behavior of selenium in
POTWs. One EPA survey of 103 POTWs revealed one POTW using
biological treatment and having selenium in the influent. The
influent concentration was 0.0025 mg/1, while the effluent
concentration was 0.0016 mg/1 giving a removal of 37 percent.
Selenium is not known to be inhibitory to POTW processes. In
another study, sludge from POTWs 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
sludae present a potential;hazard for humans or other mammuals
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
system and deposited in various body tissues, resulting in
generalized or sometimes localized gray pigmentation of the skin
and mucous membranes know 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 1 x 10-« to
5 x 10-*' 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 0.05 mg/1. Available
data show that adverse effects on aquatic life occur at total
recoverable silver concentrations as low as 1.2 x 10 3 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
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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 POTWs. 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).
Bioaccumulation and concentration of silver from sewage sludge
has not been studied to any great degree. There is some
indication 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 is little summary data available on the quantity of silver
discharged to POTWs. Presumably, there would be a tendency to
limit its discharge from a manufacturing facility because of its
high intrinsic value.
Thallium (127). Thallium (Tl) is a soft, silver-white, dense,
malleable metal. Five major minerals contain 15 to 85 percent
thallium, but they are not of commerical 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 1500 pounds.
Industrial uses of thallium include the manufacture of alloys
electronic devices and special glass. Thallium catalysts are
used for industrial organic syntheses.
I
Acute thallium poisoning in humans has been widely described.
Gastrointestinal pains and diarrhea are followed by abnormal
sensations 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.
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No reports were found regarding the behavior of thallium in
POTWs. 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 POTWs may be
precipitated 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
relatively higher concentrations of thallium than other foods
such as meat. ;
Zinc(128). Zinc occurs abundantly in the earth's crust,
concentrated in ores. It is readily refined into the^pure,
stable, silvery-white metal. In addition to its use in alloys,
zinc is used as a protective coating,on steel. It is applied by
hot dipping (i.e. dipping the steel in molten zinc) or by
electroplating. The resulting galvanized steel is used as one ol
the basis materials for coil coating. Zinc salts are also used
in conversion coatings in the coil coating industry.
Zinc can have an adverse effect on man and animals at high con-
centrations. Zincat concentrations in excess of 5 mg/1 causes
an undesirable taste, which persists through conventional
treatment. For the prevention of adverse effects due to these
organoleptic properties of zinc, 5 mg/1 was adopted for the
ambient water criterion.
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
concentrations induce cellular breakdown of the gills, and
possibly the clogging of the gills with mucous. Chronically
toxic concentrations 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 ziric 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
concentration, dissolved zinc concentration, pH, temperature, and
calcium and magnesium concentrations. Prediction of harmful
effects has been less than reliable and controlled studies have
not been extensively documented.
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The major concern with zinc compounds in marine waters is not
with acute lethal effects, but rather with the long-term
sublethal effects of the metallic compounds and complexes. Zinc
accumulates in some marine species, and marine animals contain
zinc in the range of 6 to 1500 mg/kg. From the point of view of
acute lethal effects, invertebrate marine animals seem to be the
most sensitive organism tested.
To,xicities 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 10 mg/1. Zinc
sulfate has also been found to be lethal to many plants, and it
could impair agricultural uses of the water.
Zinc is not destroyed when treated by POTWs, 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,
dissolved zinc can interfere with or seriously disrupt the
operation of POTW biological processes by reducing overall
removal efficiencies, 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 POTW facilities have been
observed by the EPA to range from 0.017 to 3.91 mg/1, with a
median concentration 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 POTWs, 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 percent 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
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can be toxic to plants, depending upon soil pH. Lettuce,
?omatoes turnips, mustard, kale, and beets are especially
sensitive to zinc contamination.
is a colorless flammable liquid
The boiling point ranges from 137
many other organic liquids. Xylene is commonly JJ mixture of
three isomers, ortho, meta, and para-xylene, with m-xylene
predominating. ' Xylene' is manufactured from pseudocumene, or by
catalytic isomerization of a hydrocarbon fraction.
Xylene is predominately used as a solvent, for the manufacure of
dveland other organics, and as a raw material -for production of
benzotc acid, phthalic anhydride and other acids and esters used
in the manufacture of polyester fibers.
Xylene has been shown to have a narcotic effect^on humans exposed
to Mgh concentrations. The chronic toxicity of xylene has not
been defined, however, it is less toxic than benzene.
on the behavior of xylene in POTWs are not available.
the methyl groups in xylene tend to transfer electrons
benzeneTino, anS make If more -usceptible.to biochemical
oxidation. This observation, in addition _to the low_ water
solubility of xylene, leads to the expectation that aeration
processes will remove some xylene from the POTW.
Ammonia. Ammonia (chemical formula NH,) is
the U.S.)
converted to ammonium compounds or
Lronfad
to 50 mg/1 ammonia.
ThP nrincinal use of ammonia and its compounds is as a
fertilizer? PHighSmounts are introduced into soils and the water
runoff from agricultural land by this use. Smaller quantities of
ammonia are Jed as a refrigerant. Aqueous ammonia ( 2 to 5
percent solution) is widely used as a household c leaner.
Ammonium compounds find a variety of uses in various industries.
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Ammonia is toxic to humans by inhalation of the gas or ingestion
of aqueous solutions. The ionized form (NH4+) is less toxic than
hone: h"^"1^ -f0.m- mgestion of as little, as' one ounce of
household ammonia has been reported as a fatal dose. Whether
inhaled or ingested, ammonia acts destructively on mucous
membrane with resulting loss of function. Aside from breaks in
=m2!Ji- amiponia refrigeration equipment, industrial hazard from
ammonia exists where solutions of ammonium compounds may be
trea^d Wlth a Stron9 alkali, releasing ammonia gas.
as 15° pm ammonia in air is reported to cause
in alr iS
amb.ient water criteria for total ammonia are pH and
temperature dependent; un-ionized ammonia criteria is 0.02 mg/1 .
The reported odor threshold for ammonia in water is 0.037 mq/1
Un-ionized ammonia is acutely or chronically toxic to many
important freshwater and marine aquatic organisms at ambient
water concentrations below 4.2 mg/1. Salmonoid fishes are
*?P™i £ sensitive to the toxic effects of un-ionized ammoniJ
at concentrations as low as 0.025 mg/1 during prolonged exposure
Because the proportion of un-ionized ammonia varies with
environmental conditions, and cannot be directly controlled in
controlled? *"' tOtal ammonia is the Pollutant which must be
The behavior of ammonia in POTWs is well documented, because it
is a natural component of domestic wastewaters. Only verv hiah
concentrations of ammonia compounds could overload POTWs One
?£*ny SnS S/?Wn fcSat concentrations of un-ionized ammonia greater
than 90 mg/1 reduce gasification in anaerobic digesters, and
concentrations of 140 mg/1 stop digestion completely. Cor?osiSn
™, ?°PPfr Plp.*n8 and excessive consumption of chlorine also
ff^i- frorohif1? ammonia concentrations. Interference with
aerobic nitrification processes can occur when larae
concentrations of ammonia suppress dissolved oxygen. Nitrites
are then produced instead of nitrates. Elevated nitrite
drinking water are known to
Fluoride ion (F-) is a non-conventional 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
fl°rine are fluorspar (CaF2) and
hoi 2 e a
Although fluorine is produced commercially in small quantities by
electrolysis of potassium bifluoride in anhydrous hydrogen
fluoride, the elemental form bears little relation to the
combined ion. Total production of fluoride chemicals in the U S
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is difficult to estimate because of the varied , uses. Large
volume usage compounds «":.,„ calcium fluoride (est. 1,5.00,000
tons in U.S.) and sodium f luoroaluminate (est. 100,000 tons in
5s )/ Some fluoride compounds and their uses are: sodium
f luoroaluminate - aluminum production; calcium fluoride -
steelmtking? hydrofluoric acid production, enamel, iron foundry;
boron Sif luoride - organic synthesis; antimony Pe»taf luoride -
f luorocarbon production; f luoboric acid and f luoborates
ele?t?oplatinq. perchloryl fluoride (C10.F) - rocket fuel
oxidize?- hydrogen fluoride - organic fluoride manufacture,
PickUng'acid in stainless steel-making,, manufacture of alumium
fiSoride; sulfur hexaf luoride - insulator in high voltage
transformers; polytetraf luoroethylene - inert plastic. Sodium
f luSfide is used at a concentration of about 1 ppm in many public
drinking water supplies to prevent tooth decay in children.
The toxic effects of fluoride on humans include severe
aastroenteritis, vomiting, diarrhea, spasms, weakness, thirst,
failing 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 "o? insecticide. Lethal doses .for adults are estimate^ to
be as low as 2.5 g. At 1.5 ppm in drinking water, mot ling of
tooth enamel is reported, and 14 ppm, consumed over a period of
ylars, may lead to deposition of calcium fluoride in bone and
tendons.
Verv few data are available on the behavior of fluoride ; in POTWs.
Under usual operating conditions in a POTW, fluorides pass
S?ough ?nto the effluent. Very little of the fluoride entering
conventional primary and secondary treatment Presses is
removed In one study of POTW influents conducted by _ the U.S.
EPA nine POTWs reported concentrations of fluoride ranging from
07 m~g/l to 1.2 mg/1, which is the range of concentrations used
for fluoridated drinking water.
Iron
Iron is a non-conventional pollutant. It is an abundant
3oand tante O> Pros . of en
Sd in commSrcial use, but it is usually alloyed with other
metals and minerals. The most common of these is .carbon.
Iron is the basic element in the production of steel. Iron with
carbon is used for casting of major. parts of machines and it can
be machined, cast, formed, and welded. Ferrous iron is used in
SlntSfihlle. powdered iron' can be sintered and used in powder.
metallurgy. Iron compounds are also used to precipitate other
369
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metals and undesirable minerals from industrial
streams.
wastewater
Corrosion products of iron in water cause staining of porcelain
fixtures, and ferric iron combines with tannin to produce a dark
violet color. The presence of excessive iron in water
discourages cows from drinking and thus reduces milk production.
High concentrations of ferric and ferrous ions in water kill most
fish introduced to the solution within a few hours. The killing
action is attributed to coatings of iron hydroxide precipitates
on the gills. Iron oxidizing bacteria are dependent on iron in
water for growth. These bacteria form slimes that can affect the
aesthetic values of bodies of water and cause stoppage of flows
in pipes.
Iron is an essential nutrient and micro-nutrient for all forms of
growth. Drinking water standards in the U.S. set a limit of 0 3
mg/1 of iron in domestic water supplies, based on aesthetic and
organoleptic properties of iron in water.
High concentrations of iron do not pass through a POTW into the
effluent. In some POTWs iron salts are added to coagulate
precipitates and suspended sediments into a sludge. In an EPA
study of POTWs the concentration of iron in the effluent of 22
biological POTWs meeting secondary treatment performance levels
ranged from 0.048 to 0.569 mg/1 with a median value of 0.25 mq/1
This represented removals of 76 to 97 percent with a median of 87
percent removal.
Iron in sewage sludge spread on land used for agricultural
purposes is not expected to have a detrimental effect on crops
grown on the land.
Manganese. Manganese is a non-conventional pollutant. It is a
gray-white metal resembling iron, but more brittle. The pure
metal does not occur in nature, but must be produced by reduction
°t B , °?lde Wlth sodium, magnesium, or aluminum, or by
electrolysis. The principal ores are pyrolusite (MnO,) and
psilomelane (a complex mixture of Mn02 and oxides of potassium
barium and other alkali and alkaline earth metals). The largest
percentage of manganese used in the U.S. is in ferro-manganese
alloys. A small amount goes into dry batteries and chemicals.
Manganese is not often present in natural surface waters because
its hydroxides and carbonates are only sparingly soluble.
Manganese is undesirable in domestic water supplies because it
causes unpleasant tastes, deposits on food during cooking, stains
and discolors laundry and plumbing fixtures, and fosters the
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growth of some microorganisms in reservoirs, filters, and
distribution systems.
Small concentrators of 0.2 to;0.3 mg/1 of manganese may cause the
formation of heavy encrustations in piping. Excessive manganese
is also undesirable in water for use in many industries,
including textiles, dyeing, food processing, distilling, brewing,
ice, and paper. ,
The recommended limitation for manganese in drinking water in the
U.S. is 0.05 mg/1. The limit appears to be based on aesthetic
and economic factors rather than physiological hazards. Most
investigators regard manganese to be of no toxicological
significance in drinking water at concentrations not causing
unpleasant tastes. However, cases of manganese poisoning have
been reported in the literature. A small outbreak of
encephalitis - like disease, with early symptoms of lethargy and
edema, was traced to manganese, in the drinking water in a village
near Tokyo. Three persons died as a result of poisoning by well
water contaminated by manganese derived from dry-cell batteries
buried nearby. Excess manganese in the drinking water is also
believed to be the cause of a rare disease in Northeastern China.
No data were found regarding the behavior of manganese in POTWs.
However, one sourcereports that typical mineral pickup from
domestic water use results in an increase in manganese
concentration of 0.2 to 0.4 mg/1 in a municipal sewage system.
Therefore, it is expected that interference in POTWs, if it
occurs, would not be noted until manganese concentrations
exceeded 0 . 4, mg/1. .
Phenols(Total). "Total Phenols" is a non-conventional 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 different 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
constant and an inexpensive monitoring method is desired. In any
given plant or even in an industry subcategory, monitoring of
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"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 POTWs the concentration of "total
phenols" ranged grom 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 22 of these same POTWs, 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 percent.
It must be recognized, however, that six of the eleven priority
pollutant 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 having any
phenol itself or any of the ten other priority pollutant phenols
present. A characterization of the phenol mixture to be
monitored to establish constancy of composition will allow "total
phenols" to be used with confidence.
Sulfides
Sulfides are oxidizable and therefore can exert an oxygen demand
on the receiving stream. Their presence, in amounts which
consume oxygen at a rate exceeding the oxygen uptake of the
stream, can produce a condition of insufficient dissolved oxygen
in the receiving water. Sulfides also impart an unpleasant taste
and odor to the water and can render the water unfit for other
uses.
Sulfides are constituents of many industrial wastes such as those
from tanneries, paper mills, chemical plants, and gas works; but
they are also generated in sewage and some natural waters by the
anaerobic decomposition of organic matter. When added to water,
soluble sulfide salts such as Na2S dissociate into sulfide ions
which, in turn, react with the hydrogen ions in the water to form
HS- or H2S, the proportion of each depending upon the resulting
pH value. Thus, when reference is made to sulfides in water, the
reader should bear in mind that the sulfide is probably in the
form of HS- or H2S.
Owing to the unpleasant taste and odor which results when
sulfides occur in water, it is unlikely that any person or animal
will consume a harmful dose. The thresholds of taste and smell
were reported to be 0.2 mg/1 of sulfides in pulp mill wastes.
For industrial uses, however, even small traces of sulfides are
372
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often detrimental.
irrigation waters.
Sulfides are of little importance in
The toxicity of solutions of sulfides toward fish increases as
the pH value is." lowered, i.e., the HeS or HS- rather than the
sulfide ion, appears to be the principle toxic agent. In water
containing 3.2 mg/1 of sodium sulfide, trout overturned in two
hours at pH 9.0, in ten minutes at pH 7.8, and in four minutes at
pH 6.0. Inorganic sulfides have proved to be fatal to sensitive
fish such as trout at concentrations between 0.5 and 1.0 mg/1 as
sulfide, even in neutral and somewhat alkaline solutions.
and grease are taken together as one
This is a conventional pollutant and some
Oil and .Grease. Oil
pollutant parameter.
of its components are:
1. Light Hydrocarbons - These include light fuels such as
gasoline, kerosene, and jet fuel, and miscellaneous sol-
vents used for industrial processing, degreasing, or
cleaning purposes. The presence of these light hydro-
carbons may make the removal of other heavier oil wastes
more difficult.
2. Heavy Hydrocarbons, Fuels, arid 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 andAnimal 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 wastewater.
Oils and greases, 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 emulsions 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 organic priority pollutants will be found distributed
between the oily phase and the aqueous phase in industrial
wastewaters. The presence of phenols, PCBs, PAHs, and almost any
other organic pollutant in the oil and grease make
characterization 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'
susceptibility. However, it has been reported that crude oil, in
concentrations as low as 0.3 mg/1, is extremely toxic to
fresh-water fish. It has been recommended that public water
supply sources be essentially free from oil and grease.
I
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
concentrations of oil and grease interfere with biological
treatment processes. The oils coat surfaces and solid particles,
preventing access of oxygen, and sealing in some microorganisms.
Land 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.
p_H. Although not a specific pollutant, pH is related to the
acidity or alkalinity of a wastewater stream. It is not,
however, a measure of either. The term pH is used to describe
the hydrogen ion concentration (or activity) present in a given
solution. 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
alkaline, 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 determining 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.
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Waters with a pH below 6.0 are corrosive to water works
structures, 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
acceptable 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,
metallocyanide 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 all subcategories in the metal molding and casting industry.
A neutral pH range (approximately 6-9) is generally desired,
because either extreme beyond this range has a deleterious effect
on receiving waters or the pollutant nature of other wastewater
constituents.
Pretreatment for regulation of pH is covered by the "General
Pretreatment 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."
Total Suspended Sol ids(TSS). Suspended solids include both
organic and inorganic materials. The inorganic compounds include
sand, silt, and clay. The organic fraction includes such
materials 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 decomposable 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
processes and cause foaming in boilers and encrustations on
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equipment 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
transformed to sludge deposit, may do a variety of damaging
things, including blanketing the stream or lake bed and thereby
destroying 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
respiratory 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
compatible with a well-run POTW. This pollutant with the
exception of those components which are described elsewhere in
this section, 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 hazard.
REGULATION OF SPECIFIC POLLUTANTS
Discussions of individual pollutants selected or not selected for
consideration for specific regulation are based on concentrations
obtained from sampling and analysis of raw wastewater streams
from six subcategories.
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Aluminum Casting Subcateqory
Pollutants Considered for Specific
Regulation in the Aluminum Casting Subcategory
Based on sampling results and examination of the aluminum casting
subcategory manufacturing processes and raw materials, forty-one
pollutants were selected for consideration for specific
regulation through effluent limitations and standards for this
subcategory. These pollutants were found in raw wastewaters from
processes in this subcategory and are amenable to control by
identified wastewater treatment practices (e.g. activated carbon
adsorption, chemical precipitation-sedimentation). Discussions
of each of these pollutants follow.
Acenaphthene (1) values were detected on 6 of the 21 sampling
days in this subcategory. The maximum concentration in this
subcategory was 0.38 mg/1. Some of the concentrations are above
the treated effluent level achievable with available specific
treatment methods. This pollutant may be found in the leakages,
which subsequently contaminate process wastewaters, from die
casting operations.
Benzidine (5) values were detected on 1 of the 21 sampling days
in this subcategory. The concentration found on this day was
2.76 mg/1, a value substantially greater than the treated
effluent levels achievable with available treatment methods.
Carbon tetrachloride (6) values were detected on 11 of the 21
sampling days in this subcategory. The maximum concentration
found in this subcategory was 0.25 mg/1. Some of the
concentrations are above the treated effluent levels achievable
with available specific treatment methods. This, pollutant is
used in metal degreasing and as a general solvent in process
solutions.
Chlorobenzene (7) values were detected on 2 of the 21 sampling
days in this subcategory. The maximum concentration found was
0.59 mg/1. Some of the concentrations are above the treated
effluent levels achievable with available specific treatment
methods. This pollutant's presence is , associated with the
process solutions used in this subcategory.
1,2-dichloroethane (10) values were detected on 4 of the 21
sampling days in. this subcategory. The maximum concentration
found was 0.33 mg/1. Some of; the concentrations are above the
treated effluent levels achievable with available specific
treatment methods. This pollutant is used as a solvent for
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various process solutions, as a metal degreasing agent, and as a
wetting or penetrating agent.
1,1t 1-trichloroethane (11) values were detected on 9 of the 21
sampling days in this subcategory. The maximum concentration
found was 16.95 mg/1. This pollutant's presence is associated
with the process solutions used in this subcategory.
l',1-dichloroethane (13) values were detected on 1 of the 21
sampling days in this subcategory. The maximum concentration
found was 0.105 mg/1. This pollutant is used as a solvent in
process solutions.
2,4,6-trichlorophenol (21) values were detected on 13 of the 21
sampling days in this subcategory. The maximum concentration
found was 2.0 mg/1. Some of the concentrations are above the
treated effluent levels achievable with available specific
treatment methods. This pollutant is used as an agent to control
biological growth in various process solutions.
Parachlorometacresol (22) values were detected on 7 of the 21
sampling days in this subcategory. The maximum concentration
found was 0.925 mg/1. Some of these concentrations are well
above the optimum expected 30-day average treated effluent levels
achievable with available treatment methods. The presence of
this pollutant is associated with the contamination of process
waters with process equipment lubricants and fluids.
Chloroform (23) values were detected on all 21 sampling days in
this subcategory. The maximum concentration found was 0.46 mg/1.
Some of the concentrations are above the treated effluent levels
achievable with available specific treatment methods. This
pollutant is used as a general solvent in this and other
subcategories.
2,4-dichlorophenol (31) values were detected on 8 of the 21
sampling days in this subcategory. The maximum concentration
found was 0.15 mg/1. Some of the concentrations are above the
treated effluent levels achievable with available specific
treatment methods. This pollutant's presence is related to the
solutions used in processes and process equipment in this
subcategory.
Fluoranthene (39) values were detected on 15 of the 21 sampling
days in this subcategory. The maximum concentration found was
5.8 mg/1. Some of the concentrations are substantially above the
treated effluent levels achievable with available specific
treatment methods. This pollutant's presence is related to the
process solutions used in this subcategory.
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Methylene chloride (44) values were detected on 16 of the 21
sampling days in this subcategory. The maximum concentration
found was 2.46 mg/1. Some of these concentrations are above the
optimum expected 30-day average treated effluent levels
attainable with available specific treatment methods. The
presence :of this pollutant is related to its use in various
process solutions.
Naphthalene (55) values were detected on 8 of the 21 sampling
days in this subcategory. The maximum concentration found was
2.87 mg/1. Some of these ; concentrations are well above the
optimum expected 30-day average treated effluent levels
achievable with available treatment methods. This pollutant's
presence is related to the process solutions used.
4-nitrophenol (58) values were detected on 1 of the 21 sampling
days in this subcategory. The concentration found on this day
was 0.45 mg/1, a concentration above the optimum expected 30-day
average treated effluent level achievable with available
treatment methods. The presence of this pollutant is related to
the solutions used in the processes.
N-nitrosodi-n-propylamine (63). values were detected on 2 of the
21 sampling days' in this subcategory. The maximum concentration
found was 0.078 mg/1. This pollutant's presence is associated
with the process solutions used in this subcategory.
Pentachlorophenol (64) values were detected on 2 of the 21
sampling days in this subcategory. The maximum concentration
found was 3.05 mg/1. Some of the concentrations are
substantially above the treated effluent levels achievable with
available specific treatment methods. This pollutant is used as
an agent to control biological growth in process solutions. This
pollutant's presence may also be related to the contamination of
process wastewaters with process equipment fluids and lubricants.
Phenol (65.)-. values were detected on 15 of the 21 sampling days in
this subcategory. The maximum concentration found was 36.0 mg/1.
Some of these concentrations are above the optimum expected
30^day average treated effluent levels achievable with available
treatment methods. This pollutant is present as a major
component of various process solutions and of process equipment
fluids.
Bis(2-ethylhexyl)phthalate (66) values were detected on all 21
sampling days in this subcategory. The maximum concentration
found was 482.4 mg/1. Some of the concentrations are
substantially above the treated effluent levels achievable with
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available specific treatment methods. This pollutant's presence
can be related to the solutions used in the processes and to the
fluids used in process equipment.
Butyl benzyl phthalate (67) values were detected on 12 of the 21
sampling days in this subcategory. The maximum concentration
found was 2.0 mg/1. Some of these concentrations are above the
optimum expected 30-day average treated effluent levels
attainable with available specific treatment methods. The
presence of this pollutant can also be associated with the
solutions used in the processes and with the fluids used in
process equipment.
Benzo(a)anthracene (72) values were detected on 6 of the 21
sampling days in this subcategory. The maximum concentration
found was 22.54 mg/1. Some of the concentrations are
substantially above the treated effluent levels achievable with
available specific treatment methods. This pollutant can be
found in the solutions used in this subcategory's processes.
Benzo(a)pyrene (73) values were detected on 5 of the 21 sampling
days in this subcategory. The maximum concentration found was
0.16 mg/1. Some of these concentrations are above the optimum
expected 30-day average treated effluent levels achievable with
available treatment methods. As with b$nzo(a)anthracene, this
pollutant can be found in process solutions.
Chrysene (76) values were detected on 9 of the 21 sampling days
in this subcategory. The maximum concentration found was 19.0
mg/1. Some of the concentrations are above the treated effluent
levels achievable with available specific treatment methods.
This pollutant's presence is related to the process solutions
used in this subcategory.
Acenaphthylene (77) values were detected on 8 of the 21 sampling
days in this subcategory. The maximum concentration found was
1.64 mg/1. Some of these concentrations are well above the
optimum expected 30-day average treated effluent levels
achievable with available treatment methods. The presence of
this pollutant can be attributed to the process solutions used.
Anthracene (78) values were detected on 9 of the 21 sampling days
in this subcategory. The maximum concentration found was 1.35
mg/1. Some of these concentrations are above the optimum
expected 30-day average treated effluent levels achievable with
available specific treatment methods. This pollutant can be
found in process solutions used in this subcategory.
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Fluorene (80) values were "detected on 10 of the 21 sampling days
in this subcategory. The maximum concentration found was 7.27
mg/1. Some of the concentrations are substantially above the
treated effluent levels achievable with available specific
treatment methods. Fluorene can be found in various process
solutions (e.g., die lubes).
Phenanthrene (81) values were detected on 9 of the 21 sampling
days in this subcategory. The maximum concentration found was
1.35 mg/1. Some of the concentrations are above the treated
effluent levels achievable with available specific treatment
methods. This pollutant's presence in process wastewaters is
attributable to its presence in process solutions.
Pyrene (84) values were detected on 15 of the 21 sampling days in
this subcategory. The maximum concentration found was 0.69 mg/1.
Some of these concentrations are above the optimum expected
30-day average treated effluent levels achievable with available
treatment methods. Pyrene can be found in many of the process
solutions used by plants in this subcategory,
Tetrachloroethylene (85) values were detected on 14 of the 21
sampling days in this subcategory. The maximum concentration
found was 0.255 mg/1. Some of the concentrations are above the
treated effluent levels achievable with available specific
treatment methods. The presence of this pollutant in this
subcategory's wastewaters is related to its use as a solvent and
as a drying agent for metals.
Trichloroethylene (87) values were detected on 14 of the 21
sampling days in this subcategory. The maximum concentration
found was 0.328 mg/1. Some of the concentrations are above the
treated effluent levels achievable with available specific
treatment methods. This pollutant's presence results from its
use as a solvent in process solutions and for metal degreasing.
Chlordane (91) values were detected on 6 of the 13 sampling days
in this subcategory. The maximum concentration found was 0.24
mg/1. Some of these concentrations are above the optimum
expected 30-day average treated effluent levels achievable with
available treatment methods. Although most commonly known as a
pesticide, chlordane is also used in oil emulsions and
dispersible liquids. These latter two uses are related to the
process solutions of this subcategory.
Xylene (130) values were detected on 6 of the 21 sampling days in
this subcategory. The maximum concentration found was 70.09
mg/1. Some of the concentrations are substantially above the
treated effluent levels achievable with available specific
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treatment methods. This pollutant is used as both a protective
coating and a solvent in process solutions.
Copper (120) values were detected on all 14 sampling days in this
subcategory. The maximum concentration found was 1.11 mg/1.
Some of these concentrations are above the optimum expected
30-day average treated effluent levels achievable with available
treatment methods. The presence of copper in process wastewaters
is related to its use as an alloying material, as well as to its
use in various items of process equipment (dies, etc.).
Lead (122) values were detected on all 20 sampling days in this
subcategory. The maximum concentration found was 3.9 mg/1. Some
of the concentrations are above the treated effluent levels
achievable with available specific treatment methods. Lead
contamination in process wastewaters results from the presence of
lead in process equipment and facilities.
Zinc (128) values were detected on all 20 sampling days in this
subcategory. The maximum concentration found was 9.1 mg/1. Some
of these concentrations are above the optimum expected 30-day
average treated effluent levels achievable with available
treatment methods. Zinc's presence as a process wastewater
contaminant is related to its use as an alloying material, as
well as to its use in process equipment and facilities.
Total suspended solids (TSS) values were found on all 20 sampling
days at concentrations as high as 1632.7 mg/1. These TSS
concentrations are above the treated effluent levels achievable
with available treatment technologies. In addition, the control
of TSS in wastewater discharges will also result in the control,
to a certain extent, of several toxic pollutants. Consequently,
TSS is considered for specific regulation in this subcategory.
Oil and grease values were detected on all 20 sampling days. The
maximum concentration found was 23,273 mg/1. Oils and greases,
as process wastewater pollutants, originate in the solutions,
products, and scrap used in this subcategory's processes. As
many of the concentrations are greater than the treated effluent
levels typically achievable, oil and grease is considered for
specific regulation in this subcategory.
pH can be controlled within the limits of 7.5 to 10.0 with
available specific treatment methods and is, therefore,
considered for specific regulation in this subcategory.
Ammonia values were detected on all 20 sampling days. The
maximum concentration found was 25.2 mg/1. As a number of the
concentrations are greater than the treated effluent levels
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attainable with available treatment technologies, ammonia is
considered for specific regulation in this subcategory. Ammonia
can result from the biological degradation of organic
constituents in the process solutions.
Sulfide values were detected on all 20 sampling days. The
maximum level detected was:37.0 mg/1. As many of these values
are greater than the treated effluent levels achievable with
specific available treatment methods, sulfide is considered for
specific regulation in this subcategory. Sulfide can be
generated as a result of the biological degradation of process
solution organic compounds.
Phenols values were detected on all 20 of the sampling days in
this subcategory. The maximum concentration found was 88.41
mg/1. Some of the concentrations are substantially above the
treated effluent levels achievable with available specific
treatment methods. This pollutant, detected by wet chemistry
techniques (4AAP), encompasses a variety of the individual
phenolic compounds. This pollutant's presence in process
wastewaters is related to the constituents of process solutions.
Pollutants Not Considered for Specific
Regulation in the Aluminum Casting Subcateqory
A total of ninety-six pollutants that were evaluated were
eliminated from further consideration for specific regulation in
the aluminum casting subcategory. Forty pollutants were dropped
from further consideration, because their presence in raw process
wastewater was not detected in this subcategory. Nineteen
pollutants were eliminated from further consideration, because
the concentrations of these pollutants were less than the
analytically quantifiable limits.
The remaining thirty-seven pollutants were found to be present
infrequently or found at levels below those usually achieved by
end-of-pipe treatment technologies. Discussions of these
pollutants follow.
Benzene (4) concentrations appeared on 16 of 21 process sampling
days in the aluminum subcategory. The maximum concentration was
0.335 mg/1. Eleven concentrations are lower than the analytical
quantification limit. Three of the remaining five concentrations
are lower than the level considered to be achievable with
available specific treatment methods. However, all five
concentrations are lower than the level considered likely to
cause toxic effects in humans. Therefore, benzene is not
considered for specific regulation in this subcategory.
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1,1,2,2-tetrachloroethane (15) concentrations appeared on 3 of 21
process sampling days in the aluminum subcategory. The maximum
concentration was 0.013 mg/1. One concentration is below the
analytically quantifiable limit. The maximum concentration is
less than the concentration achievable by specific treatment
methods. Therefore, this pollutant is not considered for
specific regulation in this subcategory.
Bis(2-chloroethyl)ether (18) concentrations appeared on 1 of 21
process sampling days in the aluminum subcategory. The
concentration was 0.024 mg/1. Because this toxic pollutant was
found at only one plant, bis(2-chloroethyl)ether is not
considered for specific regulation in this subcategory.
2-chlorophenol (24) concentrations appeared on 4 of 21 process
sampling days in the aluminum subcategory. The maximum
concentration was 0.235 mg/1. Two concentrations are below the
analytically quantifiable limit. Another concentration is lower
than the level considered to be achievable by specific treatment
methods. Because this toxic pollutant was found on only one
process sampling day at a level considered to be achievable with
available specific treatment methods, 2-chlorophenol is not
considered for specific regulation in this subcategory.
2,4-dimethylphenol (34) concentrations appeared on 9 of 21
process sampling days in the aluminum subcategory. The maximum
concentration was 0.13 mg/1. Five concentrations are below the
analytical quantification limit. Two other concentrations are
lower than the level considered to be achievable by specific
treatment methods. The two remaining concentrations are lower
than trie level considered to cause toxic effects in humans.
Therefore, 2,4-dimethylphenol is not considered for specific
regulation in this subcategory.
Ethylbenzene (38) concentrations appeared on 6 of 21 process
sampling days in the aluminum subcategory. The maximum
concentration was 0.033 mg/1. Five concentrations are below the
analytically quantifiable limit. The maximum concentration is
below the level considered to be achievable by specific treatment
methods. Therefore, ethylbenzene is not considered for specific
regulation in this subcategory.
Dichlorobromomethane (48) concentrations^ appeared on 7 of 21
process sampling days in the aluminum subcategory. The maximum
concentration was 0.017 mg/1. Five concentrations are below the
analytically quantifiable limit. The remaining two
concentrations are lower than the level considered to be
achievable by specific treatment methods. Therefore,
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dichlorobromornethane is not considered "for specific regulation in
this subcategory.
2-nitrophenol (57) concentrations appeared on 3 of 21 process
sampling days in the aluminum subcategory. The maximum
concentration was 1.0 mg/1. One concentration is below the
analytically quantifiable limit. Another concentration is below
the level considered to be achievable with available specific
treatment methods. Because this toxic pollutant was found on
only one process sampling day at a level considered to be
achievable with available specific treatment methods,
2-nitrophenol is not considered for specific regulation in this
subcategory.
2,4-dinitrophenol (59) concentrations appeared on 2 of 21 process
sampling days in the aluminum subcategory. The maximum
concentration was 0.41 mg/1. One concentration is below the
analytically quantifiable limit. Because this toxic pollutant
was found on only one sampling day at a level considered to be
achievable with available specific treatment methods,
2,4-dinitrophenol is not considered for specific regulation in
this subcategory.
4 6-dinitro-o-cresol (60) concentrations appeared on 3 of 21
process sampling days in the aluminum subcategory.' The maximum
concentration was 0.285 mg/1. Two concentrations are below the
analytically quantifiable limit. Because this toxic pollutant
was found on only one sampling day at a level considered to be
achievable with specific treatment methods, 4,6-dinitro-o-cresol
is not considered for specific regulation; in this subcategory.
Di-n-butyl phthalate (68) concentrations appeared on 18 of 21
process sampling days in the aluminum subcategory. The maximum
concentration was 23.6 mg/1. Eight concentrations are below the
analytically quantifiable limit. Many other concentrations are
lower than the level considered to be achievable with available
specific treatment methods. Therefore, di-n-butyl phthalate is
not considered for specific regulation in this subcategory.
Diethyl phthalate (70) concentrations appeared on 11 of 21
process sampling days in the aluminum subcategory. The maximum
concentration was 9.09 mg/1. Five concentrations are below the
analytically quantifiable limit. Many other concentrations are
at levels that are considered achievable with available specific
treatment methods. However, all of the concentrations were below
the human toxicity level for this pollutant. Therefore, diethyl
phthalate is not considered for specific regulation in this
subcategory. ,
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Dimethyl phthalate (71) concentrations appeared on 5 of 21
process sampling days in the aluminum subcategory. The maximum
concentration was 0.035 mg/1. Four concentrations are below the
analytically quantifiable limit. The maximum concentration is
slightly above the level that is considered achievable with
available specific treatment methods. Therefore, dimethyl
phthalate is not considered for specific regulation in this
subcategory.
Toluene (86) concentrations appeared on 14 of 21 process sampling
days in the aluminum subcategory. The maximum concentration was
1.02 mg/1. Eleven concentrations are below the analytically
quantifiable limit. One other concentration is lower than the
level considered to be achievable wi|th available specific
treatment methods. Therefore, toluene is not considered for
specific regulation in this subcategory.
Aldrin (89) concentrations appeared on 6 of 13 process sampling
days in the aluminum subcategory. The maximum concentration was
0.018 mg/1. Five concentrations are below that level achievable
with end-of-pipe treatment technologies. Because this toxic
pollutant appeared on only one process sampling day at an
analytically quantifiable limit, aldrin is not considered for
specific regulation in this subcategory.
4,4'-DDT (92) concentrations appeared on 9 of 13 process sampling
days in the aluminum subcategory. The maiximum concentration was
0.017 mg/1. Eight of the nine concentrations are below the
analytically quantifiable level. Because only one quantifiable
value was found, 4,4'-DDT is not considered for specific
regulation in this subcategory.
4,4'-DDE (93) concentrations appeared on 6 of 13 process sampling
days in the aluminum subcategory. The maximum concentration was
0.013 mg/1. Five concentrations are below the analytically
quantifiable limit. Because only one quantifiable value
appeared, 4,4'-DDE is not considered for specific regulation in
this subcategory.
Heptachlor epoxide (101) concentrations appeared on 4 of 13
process sampling days in the aluminum subcategory. The maximum
concentration was 0.028 mg/1. Three concentrations are below the
analytically quantifiable limit. Because this toxic pollutant
was found on only one process sampling day at an analytically
quantifiable level, heptachlor epoxide is not considered for
specific regulation in this subcategory.
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a-BHC-Alpha (102) concentrations appeared on 8 of 13 process
sampling days in the aluminum subcategory. The maximum
concentration was 0.071 mg/1. Seven concentrations are below the
analytically quantifiable limit. Because this toxic pollutant
was found on only one process sampling day at an analytically
quantifiable level, a-BHC-Alpha is not considered for specific
regulation in this subcategory.
b-BHC-Beta (103) concentrations appeared on 6 of 13 process
sampling days in the aluminum subcategory. The maximum
concentration was 0.151 mg/1. Four concentrations are below the
analytically quantifiable limit. Because this toxic pollutant
was found on only two process sampling days at an analytically
quantifiable level, b-BHC-Beta is not considered for specific
regulation in this subcategory.
11 of 13 process
The maximum
r-BHC-Gamma (104) concentrations appeared on
sampling days in the aluminum subcategory.
concentration was 0.024 mg/1. Nine concentrations are below the
analytically quantifiable limit. Because this toxic pollutant
was found on only two process sampling days at an analytically
quantifiable level, r-BHC-Gamma is not considered for specific
regulation in.this subcategory.
g-BHC-Delta (105) concentrations appeared on 7 of 13 process
sampling days in the aluminum subcategory. The maximum
concentration was 0.039 mg/1, Five concentrations are below the
analytically quantifiable limit. Because this toxic pollutant
was found on only two process sampling days at an analytically
quantifiable level, 6-BHC-Delta is not considered for specific
regulation in this subcategory.
Polychlorinated biphenols (PCB-1242, PCB-1254, PCB-1221,
PCB-1232, PCB-1248, PCB-1260, PCB-1016) (106-112) concentrations
appeared at one plant in the aluminum subcategory. The maximum
concentration was 0.013 mg/1. This concentration is above the
level considered to be achievable by specific treatment methods.
The appearance of these PCBs can be traced,to plants which at one
time used PCS bearing hydraulic fluids. Hydraulic fluids are a
necessity in the operation of die casting machinery. Prior to
1971, PCBs were used extensively in hydraulic fluids. Commercial
products containing PCBs are no longer produced in the U.S:, and
the use of these materials in hydraulic fluids has been
eliminated. However, PCB residuals can still be detected after
extensive cleaning and flushing of hydraulic oil systems which
once contained them. Because PCBs are artifacts of one time use,
and because they are no longer used, PCBs are not considered for
specific regulation in this subcategory.
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Arsenic (115) concentrations appeared on all 4 process sampling
days in the aluminum subcategory. The maximum concentration was
0.01 mg/1. Three concentrations are lower than the analytical
quantification limit. The maximum concentration is below the
level considered to be achievable with available specific
treatment methods. Therefore, arsenic is not considered for
specific regulation in this subcategory.
Chromium (119) concentrations appeared on all 11 process sampling
days in the aluminum subcategory. The maximum concentration was
0.01 mg/1. Ten concentrations are lower than the analytical
quantification limit. The maximum concentration is below the
level considered to be achievable with available specific
treatment methods. Therefore, chromium is not considered for
specific regulation in this subcategory.
Cyanide (121) concentrations appeared on all 20 process sampling
days in the aluminum subcategory. The maximum concentration was
0.05 mg/1. All concentrations are lower than the level
considered to be achievable by specific treatment methods.
Therefore, cyanide is not considered for specific regulation in
this subcategory.
Mercury (123) concentrations appeared on all 14 process sampling
days in the aluminum subcategory. The maximum concentration was
0.0014 mg/1. All concentrations are lower than the level
considered to be achievable by specific treatment methods.
Therefore, mercury is not considered for specific regulation in
this subcategory.
Nickel (124) concentrations appeared on all 14 process sampling
days in the aluminum subcategory. The maximum concentration was
0.04 mg/1. This concentration is below the level considered to
be achievable by specific treatment methods. Therefore, nickel
is not considered for specific regulation in this subcategory.
Fluoride concentrations appeared on all 20 process sampling days
in the aluminum subcategory. The maximum concentration was 3.4
mg/1. This concentration is below the level considered to be
achievable by specific treatment methods. Therefore, fluoride is
not considered for specific regulation in this subcategory.
Manganese concentrations appeared on all 20 process sampling days
in the aluminum subcategory. The maximum concentration was 0.56
mg/1. Four concentrations are below the analytical
quantification limit. Fourteen concentrations are lower than the
level considered to be achievable by specific treatment methods.
Because this pollutant was found on only two process sampling
days at a concentration above the level considered to be
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achievable by specific treatment methods, manganese is not
considered for specific regulation in this subcategory.
Iron concentrations appeared on all 12 process sampling days in
the aluminum casting subcategory. The maximum concentration was
4.2 mg/1. Three of the concentration values are below the level
considered to be analytically quantifiable. Nine of the twelve
concentration values are below the level considered to be
achievable by specific treatment methods. Therefore, iron is not
considered for specific regulation in this subcategory.
Copper Casting Subcateqory
Pollutants Considered for Specific
Regulation in the Copper Casting Subcateqory
Based on sampling results and a careful examination of the copper
casting subcategory manufacturing processes and raw materials,
thirteen pollutants were selected for consideration for specific
regulation through effluent limitations and standards for this
subcategory. These pollutants were found in raw wastewaters from
processes in this subcategory and are amenable to control by
identified wastewater treatment practices (e.g., activated carbon
adsorption, oxidation, chemical precipitation-sedimentation).
Discussions of these pollutants follow.
Butyl benzyl phthalate (67) values were detected on 4 of the 6
sampling days in this subcategory. The maximum concentration
found was 0.55 mg/1. Some of the concentrations are above the
treated effluent levels achievable with available specific
treatment methods. The presence of this pollutant is related to
the use of binders and other chemical additives in the casting
sands.
3,4-benzofluoranthene (74) values were detected on 2 of the 6
sampling days in this subcategory. The maximum concentration
found was 0.013 mg/1. Some of the concentrations are above the
treated effluent levels achievable with available specific
treatment methods. This pollutant is present as a combustion
byproduct of the binders and other sand additives.
Benzo(k)fluoranthene (75) values were detected on 2 of the 6
sampling days in this subcategory. The maximum concentration
found was 0.013 mg/1. Some of these concentrations are above the
optimum expected 30-day average treated effluent levels
achievable with available specific treatment methods. This
pollutant is present as a combustion byproduct of the binders and
other sand additives.
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Pyrene (84) values were detected on 5 of the 6 sampling days in
this subcategory. The maximum concentration found was 0.034
mg/1. Some of these concentrations are above the optimum
expected 30-day average treated effluent levels attainable with
available specific treatment methods. This pollutant is a
combustion byproduct of the binders and other sand additives.
Copper (120) values were detected on all 4 sampling days in this
subcategory. The maximum concentration found was 147.9 mg/1.
Some of these concentrations are above the optimum expected
30-day average treated effluent levels achievable with available
treatment methods. Copper is considered for specific regulation,
as it is the primary metal used in this subcategory.
Lead (122) values were detected on all 6 of sampling days in this
subcategory. The maximum concentration found was 32.1 mg/1.
Some of the concentrations are above the treated effluent -levels
achievable with available specific treatment methods. Lead's
presence as a process wastewater pollutant is related to its use
as an alloying material, as well as to its use in process
equipment and facilities.
Nickel (124) values were detected on all 4 sampling days in this
subcategory. The maximum concentration found was 1.02 mg/1.
Some of these concentrations are above the optimum expected
30-day average treated effluent levels achievable with available
treatment methods. The presence of nickel in process wastewaters
is a result of its use as an alloying material for copper, as
well as its use in process equipment (molds, etc.) and
facilities.
Zinc (128) values were detected on all 6 sampling days in this
subcategory. The maximum concentration found was 144.6 mg/1.
Some of the concentrations are above the treated effluent levels
achievable with available specific treatment methods. The
presence of this pollutant is attributed to its use as an alloy
for copper and to its use in production equipment and facilities.
Total suspended solids were found on all 6 sampling days. The
maximum concentration found was 773.9 mg/1. The TSS
concentrations are greater than the treated effluent levels
achievable with available treatment technologies. In addition,
control of TSS in process wastewater discharges will result in
the control, to a certain extent, of several toxic pollutants.
Therefore, this pollutant is considered for specific regulation.
Oil and grease values were found on all 6 sampling days. The
maximum concentration was 110 mg/1. As these concentrations are
greater than the treated effluent levels typically achievable
390
-------
with specific treatment technologies, oil and grease is
considered for specific, regulation in this subcategory.
nH can be controlled within the limits of 7.5 to 10.0 with
available spec??ic treatment methods and is therefore considered
for specific regulation in this subcategory.
values were detected on all 6 sampling days. The
concentration found was "0.97 wg/1. Js severa 1^ of these
concentrations are greater than the treated effluent levels
acSiSSSe 5i!h specific treatment technologies manganese is
considered for specific regulation in this subcategory.
^un
cncnr ons are greater than the treated effluent levels
acnle^aole with specified treatment technologies phenol is
considered for specific regulation in this subcategory.
Pollutants Not Considered for Specific
Regulation in the Copper Casting Subcateqory
A total of one hundred twenty-four pollutants which were
evaluated were eliminated from further consideration for specif ic
regulation in the copper casting subcategory. Fifty one
nollutants were dropped from further consideration because their
^esence in ?aw wastewaters was not detected. Forty pollutants
lire eliminated from further consideration, beca^ £he
concentrations of these pollutants were less than the
analytically quantifiable limits.
The remaining thirty-three pollutants were found to be present
InlrequenV or found at levels below those usually achieved^
specific treatment methods. Discussions of these pollutants
follow.
Acenaphthene (1) concentrations appeared on 4 of 6 Process
csamnling davs in the copper subcategory. The maximum
?onc"en?ratiof was 0.011 mg/1 Three concentration values appear
belSS the level considered to be analytically quantifiable. The
rtmSining concentration value is only slightly above the level
co^slderld to be achievable with available specific treatment
Se?hodl! Therefore, acenaphthene is not considered for specific
regulation in this subcategory.
Carbon tetrachloride (6) concentrations appeared
SocSss sampling days in , the copper subcategory
?oncSlral?Sn wa2 0.032 mg/1.
This concentration
on 1 of 6
. The maximum
is below the
391
-------
level considered to be achievable by specific treatment methods.
Therefore, carbon tetrachloride is not considered for specific
regulation in this subcategory.
i
1,1,1-trichloroethane (11) concentrations appeared on 1 of 6
process sampling days in the copper subcategory. The maximum
concentration was 0.14 mg/1. Because this toxic pollutant was
found at only one plant, 1,1,1-trichloroethane is not considered
for specific regulation in this subcategory.
1,1,2-trichloroethane (14) concentrations appeared on 1 of 6
process sampling days in the copper subcategory. The maximum
concentration was 0.013 mg/1. Because this toxic pollutant was
found at only one plant, and the maximum concentration is less
than the concentration achievable by specific treatment methods,
1,1,2-trichloroethane is not considered for specific regulation
in this subcategory.
Chloroform (23) concentrations appeared on all 6 process sampling
days in the copper subcategory. The maximum concentration was
0.093 mg/1. Five concentration values are below the level
considered to be analytically quantifiable. The remaining
concentration is less than the concentration achievable by
specific treatment methods. Therefore, chloroform is not
considered for specific regulation in this subcategory.
2,4-dimethylphenol (34) concentrations appeared on 3 of 6 process
sampling days in -the copper subcategory. The maximum
concentration was 0.084 mg/1. This concentration is only
slightly above the level considered to be achievable with
available specific treatment methods. Therefore,
2,4-dimethylphenol is not considered for specific regulation in
this subcategory.
2,6-dinitrotoluene (36) concentrations appeared on 1 of 6 process
sampling days in the copper subcategory. The concentration was
0.012 mg/1. The concentration value is below the level
considered to be achievable by specific treatment methods.
Therefore, 2,6-dinitrotoluene is not considered for specific
regulation in this subcategory.
Methylene chloride (44) concentrations appeared on 3 of 6 process
sampling days in the copper subcategory. The maximum
concentration was 0.016 mg/1. Two concentration values are below
the level considered to be analytically quantifiable. The
remaining concentration value is below the level considered to be
achievable by specific treatment methods. Therefore, methylene
chloride is not considered for- specific regulation in this
subcategory.
392
-------
Methyl chloride (45) concentrations appeared on 1 of 6 Process
sampling days in the copper subcategory. The maximum
concentration was 0.028 mg/1. This concentration is below the
level considered to be achievable by specific treatment methods.
Therefore, methyl chloride is not considered for specific
regulation in this subcategory.
Isophorone (54) concentrations appeared on 3 of 6 process
sampling days in the copper subcategory. The maximum
c5n?en?rationywas 0.015 mg/1. Two concentration values are below
the level considered to be analytically quantifiable. The other
concentration value is below the level considered to be
a?hiSvable by specific treatment methods. Therefore, isophorone
is not considered for specific regulation in this subcategory.
4-nitrophenol (58) concentrations appeared on 2 of 6 process
sailing days in the copper subcategory The maximum
concentration was 0.019 mg/1. This concentration is below the
level considered to be achievable by specific treatment methods.
Therefore, 4-nitrophenol not considered for specific regulation
in this subcategory.
Pentachlorophenol (64.) concentrations appeared on 4 of 6 process
sapling days in the copper subcategory. The maximum
concentration was 0.051 mg/1. Only one concentration value was
detected above the level considered to be achievable with
available specific treatment methods.. Therefore
pentachlorophenol is not considered" for specific regulation irt
this subcategory.
Phenol (65) concentrations appeared on 5 of 6 process sampling
days in the copper subcategory. The maximum concentration was
0 031 ma/1. Two concentration values are below -the < level
considered to be analytically quantifiable. This concentration
is below the level considered to be achievable by-specific
treatment methods. Therefore, phenol is not considered for
specific regulation in this subcategory.
Bis(2-ethvlhexyl) phthalate (66) concentrations appeared on all 6
procesfsampling days in the copper subcategory The maximum
Concentration was 0.15 mg/1. However, this co^!fratl^e^f^f
lower than the human toxicity level. Therefore,
bis(2-ethylhexyl) phthalate is not considered for specific
regulation in this subcategory.
Di-n-butyl phthalate (68) concentrations appeared on 5 of 6
process sampling days in the copper subcategory. The maximum
Concentration was 0.023 mg/1. Two concentration values are below
the level considered to be analytically quantifiable. The
393
-------
maximum concentration is below the level considered to be
achievable by specific treatment methods. Therefore, di-n-butyl
phthalate is not considered for specific regulation in this
subcategory.
Diethyl phthalate (70) concentrations appeared on 5 of 6 process
sampling days in the copper subcategory. The maximum
concentration was 0.01 mg/1. Four concentration values are below
the level considered to be analytically quantifiable. The
remaining concentration is below the level considered to be
achievable by specific treatment methods. Therefore, diethyl
phthalate is not considered for specific regulation in this
subcategory.
Dimethyl phthalate (71) concentrations appeared on 3 of 6 process
sampling days in the copper subcategory. The maximum
concentration was 0.151 mg/1. One concentration value is below
the level considered to be analytically quantifiable. Only one
concentration is above the level considered achievable with
Su?u ? Ze specific treatment methods. Therefore, dimethyl
phthalate is not considered for specific regulation in this
subcategory.
Benzo(a)anthracene (72) concentrations appeared on 1 of 6 process
«ao?iing,, ays in the c°PPer subcategory. This concentration was
0.089 mg/1. Because this toxic pollutant was found on only one
sampling day, it is not considered for specific regulation in
this subcategory.
Benzo(a)pyrene (73) concentrations appeared on 3 of 6 process
sampling days in the copper subcategory. The maximum
concentration was 0.038 mg/1. Two of the concentration values
are below the level considered to be analytically quantifiable.
Therefore, benzo(a)pyrene is not considered for specific
regulation in this subcategory.
Chrysene (76) concentrations appeared on 4 of 6 process sampling
nYoo1" copper subcategory. The maximum concentration was
0.108 mg/1. Two of the concentration values are below the level
considered to be analytically quantifiable. Therefore, chrysene
is not considered for specific regulation in this subcategory.
Acenaphthylene (77) concentrations appeared on 4 of 6 process
sampling days in the copper subcategory. The maximum
concentration was 0.013 mg/1. Three of the concentration values
are below the level considered to be analytically quantifiable.
Therefore, acenaphthylene is not considered for specific
regulation in this subcategory.
394
-------
Anthracene (78) concentrations appeared on 3 of 6 process
sampling days "in the copper subcategory. The maximum
concentration was 0.038 mg/1. These three concentration values
are either below the level considered to be analytically
quantifiable of inseparable. Therefore, anthracene is not
considered for specific regulation in this subcategory.
i ,-- .. ... - . -,»sr-,, ., . ,- , i j, .. „„
Phenanthrene (81) concentrations appeared on 3 of 6 process
sampling days in the copper subcategory. The maximum
concentration was 0.038 mg/1. These three concentration^values
are either below the level considered to be analytically
quantifiable or inseparable. Therefore, phenanthrene is not
considered for specific regulation in this subcategory.
Tetrachloroethylene (85) concentrations appeared on 3 of 6
process sampling days in the copper subcategory. The^aximum
concentration was 0.28 mg/1. Two of the concentration values are
below the level considered to be analytically quantifiable.
Therefore, tetrachloroethylene is not considered for specific
regulation in this subcategory.
Trichloroethylene (87) concentrations appeared on 1 of 6 process
sampling days in the copper subcategory. The concentration was
018 mg/1. Because this .toxic pollutant was found on only one
sampling day, is is not considered for specific regulation in
this subcategory.
Arsenic (115) concentrations appeared on both of the process
sampling days in the copper subcategory. The maximum
concentration was 0.016 mg/1. Arsenic was excluded/ from
verification analysis. This maximum concentration is below the
level considered to be achievable by specific treatment methods.
Therefore, arsenic is not considered for specific regulation in
this subcategory.
Cadmium (11 8) concentrations appeared on all 4 process sampling
days in the copper subcategory. The maximum concentration was
013 mg/1. All of the concentrations are below the level
considered to be achievable by specific treatment methods.
Therefore, cadmium is not considered for specific regulation in
this subcategory.
Cyanide (121)concentrations appeared on all 6 process sampling
days in the copper subcategory. The maximum concentration was
0 032 mg/1. All of the concentration values are below the level
considered to be achievable by specific treatment methods.
Therefore, cyanide is not considered for specific regulation in
this subcategory.
395.
-------
Mercury (123) concentrations appeared on all 4 process sampling
days in the copper subcategory. The maximum concentration was
0.0005 mg/1. One of the concentration values is below the level
considered to be analytically quantifiable. All of the values
are below the level considered to be achievable by specific
treatment methods. Therefore, mercury is not considered for
specific regulation in this subcategory.
Ammonia concentrations appeared on all 6 process sampling days in
the copper subcategory. The maximum concentration was 2.77 mg/1.
All of the concentration values are below the level considered to
be toxic in humans. Therefore, ammonia is not considered for
specific regulation in this subcategory.
Sulfide concentrations appeared on all 6 process sampling days in
the copper subcategory. The maximum conentration was 1 .-3 mg/1
Four of the concentration values are below the level considered
to be analytically quantifiable. The remaining two concentration
values are above the levels considered to be achievable by
specific treatment methods for their respective operations
However, sulfide is not considered for regulation in this
subcategory.
Fluoride concentrations appeared on all 6 process sampling day's
in the copper subcategory. The maximum concentration was
4.2 mg/1. All of the concentration values are below the level
considered to be achievable by specific treatment methods.
Therefore, fluoride is not considered for regulation in this
subcategory.
Iron concentrations appeared on all 3 process sampling days in
the copper casting subcategory. The maximum concentration was
0.07 mg/1. All of the concentration values are below the level
considered to be achievable by specific treatment methods.
Therefore, iron is not considered for specific regulation in this
subcategory.
j
Ferrous Casting Subcategory
Pollutants Considered for Specific
Regulation in the Ferrous Casting Subcateqorv
Based on sampling results and careful examination of the ferrous
casting subcategory manufacturing processes and raw waste
materials, thirty-five pollutants were selected for consideration
for specific regulation through effluent limitations and
standards for this subcategory. These pollutants were found in
raw wastewaters from processes in this subcategory and are
amenable to control by identified wastewater treatment practices.
396
-------
(eg., activated carbon adsorption, chemical
precipitation-sedimentation). - Disucssions of these pollutants
follow. . .._...
Acenaphthene (1) values were detected on 27 of the 32 sampling
days in this subcategory. The maximum concentration found was
0 081 mg/1. Some of the concentrations are above the^ treated
effluent levels achievable with available specific treatment
methods. Acenaphthene may be found in dust collection and sand
washing wastewaters and in various casting sand additives.
2-chlorophenol (24) values were detected on 17 of the 32^sampling
days in this subcategory. The maximum concentration found was
0.082 mg/1. Some of these concentrations are above the optimum
expected 30-day average treated effluent levels achievable with
available treatment methods. This pollutant is present as a
result of the materials used in Discussions of these pollutants
follow. the melting process. _.
2,4-dichlorophenol (31) values were detected on 14 of the 32
sampling days in this subcategory. The maximum concentration
found was 0.372 mg/1. Some of the concentrations are above the
treated effluent levels achievable with available specific
treatment methods. This pollutant originates i«: the-, products
used in the casting processes (ie., casting sand additives).
2,4-dimethylphenol (34) values were detected on 22 of^the.32
sampling days in this subcategory. The maximum concentration
found was 1.2 mg/1. Some of these concentrations are above the
optimum expected 30-day average treated effluent levels
achievable with available treatment methods. This pollutant may
also originate in the products used in the casting and melting
porcesses.
Fluoranthene (39) values were detected on 30 of the 32 sampling
days in "this subcategory. The maximum concentration .found was
1.5 mg/1. Some of the concentrations are above the? treated
effluent levels achievable with available specific treatment
methods. This contaminant's presence is related to the use of
coke in the melting process. As the coke is combusted, this
pollutant may be evolved as a by-product.
2,4-dinitrophenol (59) values were detected on 8^. of-the_32.
sampling days in this subcategory. The maximum concentration
found was 0.13 mg/1. Some of the concentrations are above the
treated effluent levels achievable with available specific
treatment methods. This pollutant's presence can^also_be related
to the raw materials (coke and oily scrap) .used in the melting
processes. ,
397
-------
4,6-dinitro-o-cresol (60) values were detected on 1 2 of the 32
fon^f n^ in/1this subcategory. The maximum concentration
found was 0.137 mg/1 . Some of these concentrations are above the
optimum expected 30-day average treated effluent levels
be found ?„ fhth available treatment methods. This pollutant may
be found in this subcategory 's process wastewaters as a result of
the raw materials used in the melting process.
N-nitrosodiphenylamine (62) values were detected on 1 4 of the 32
?an£;r!!g cay,S il]1 this subcategory. The maximum concentration
found was 5.95 mg/1. Some of the concentrations are well above
the treated effluent levels achievable with available specific
treatment methods. This pollutant's presence is related to the
raw materials used in the melting process.
Pentachlorophenol (64) values were detected on 1 3 of the 32
Snn£iing dar,vn t/^S subcategory. The maximum concentration
found was 0.47 mg/1. Some of these concentrations are above the
optimum expected 30-day average treated effluent levels
aailable treatment methods. The presence of
aSSOCiated *ith the raw materials used in
det?cted on 27 of the 32 sampling days in
o h maximum concentration found was 7.4 mg/1.
Some of the concentrations are well above the treated effluent
Phenof'^nriSlf16- Wlt? arilable sPedfic treatment methods^
Phenol s presence is related to the use of coke and oily scrap in
the melting process and to the binders and other additives used
in CHStixncj
Butyl benzyl phthalate (67) values were detected on 23 of the 32
Knni1"9 yn ^ thi/S subcategory. The maximum concentration
found was 0.32 mg/1. Some of the concentrations are above the
treated effluent levels achievable with available specific
treatment methods. This pollutant's presence is related to the
materials used in the casting and melting processes.
Benzo( a) anthracene (72) values were detected on 15 of the 32
fnnSi^L naXS-7 in/-,this, subcategory. The maximum concentration
found was 0.047 mg/1. Some of these concentrations are above the
optimum expected 30-day average treated effluent levels
achievable with available treatment methods. This pollutant may
be found as a result of the raw materials used in the melting
(76) values were detected on 22 of the 32 sampling days
Categ°ry; ,?he maximum concentration found was
. Some of the concentrations are above the treated
Chrysene
S VQ
U.U29
398
-------
effluent levels achievable with available specific treatment
methods This pollutant's presence is related to the raw
mlte??lis used inPthe melting .process and to the ^ binders and
other additives used in the casting sand. This polluant is also
a combustion by-product of coke and the sand additives.
Arenaohthvlene (77) values were detected on 25 of the 32 sampling
davS in thi? subcategory. The maximum concentration found was
043 mg/1 . S me of thele concentrations are above the optimum
exacted 30-day average treated effluent levels achievable with
Ivatlable treatment methods. This pollutant's origin is
IsSociatSd with the raw materials used in the melting process.
Fluorene (80) values were detected on 27 of the 32 sampling days
in tM.1 subcategory. The maximum concentration found was
18 mg/1 Some of the concentrations are above the treated
effluent levels achievable with available specific treatment
methods. As with chrysene, this pollutant is a combustion
by-product of coke and the sand additives.
Phenanthrene (81) values were detected on 27 of the 32 sampling
davS in this subcategory. The maximum concentration found was
OH mg/1 . Some of theSe concentrations are above the optimum
expected 30-day average treated effluent levels attainable with
available specific treatment methods.
Pyrene (84) values were detected on 29 of the 32 sampling days in
this subcategory. The maximum concentration found was 3.3 mg/1.
SomS of thele concentrations are well above the optimum expected
30-day average treated effluent levels achievable with available
treatment methods. This pollutant may ^^ UStl°n
by-product of the casting sand binders and other
(85)
values were detected on 27 or the 32
Tetrachloroethylene
" ?yf Is
raw materials used in the melting process.
Antimony (114) values were detected on all 19 sampling days in
this subcateqorv. The maximum concentration found was 1.4 mg/1.
ISml'of thSs? concentrations , are above the optimum expected
30-dav average treated effluent levels achievable with available
treatment methods. The presence of this pollutant is related to
its use as an alloy.
Arsenic (115) values were detected on 25 of the 27 sampling days
tn this subcategory. The maximum concentration found was
399
-------
i i* -,Some Of the
effluent levels achievable
wlstewlters Sar1i,Utant iS
meftfnfprocess ^ 1S *
concentrations are above the treated
with available specific treatment
resfnt.in thi* subcategory ' s p?oc1ss
contaminant - the coke used in the
Cadmium (118) values were detected on 25 of the 26 sampling days
*n this subcategory. The maximum concentration foCnd was
Some of these concentrations are above the optimum
30-day average treated effluent levels achievable with
treatment methods. The presence of this pollutant is
use as an alloy. It may also be present as a
of plated materials in the
Chromium
in this
3.1 mg/1,
effluent
methods.
alloying
sands.
(I,!2i ^alues were detected on 26 of the 27 sampling days
subcategory The maximum concentration found waS
borne of the concentrations are above the treated
Th s non^n^ Wlth available specific trea?men?
This pollutant's presence is related to its use as an
material or as a result of its washing from chromite
Copper (120) values were detected on all 60 sampling davs in
- "
te
Lead (122) values were detected on all 63 sampling davs in
Iom2ao?g?hr The maXimUm ^centration Sn^w^s 0 mg/
Ha?f Se^a%eC?rneae^ae^
- This pollutant
Nickel (124) values were detected on 58 of the 59 sampling days
0 98 la/1 ^oSfo?0^' The maximum concentration foSnd wal
SS Concentrations are above the optimum
pollutant is related to its use ,as, an alloy in
pollutant
as a contaminant in the scrap charge
400
-------
Total suspended solids values were^found on a*y
The maximum concentration found was 39,000 mg/1. The TSS
concentrations are greater than the typically achievable effluent
levels and are, therefore, considered for specific Regulation-
in addition, the control of TSS will result in the control, to a
certain extent, of several toxic pollutants.
Oil and grease values were detected on all 63 sampling days. The
once^r .t^S^tT than° B^fluXt 1=3. t&c.ft
achievable Si 1 and grease is considered for specific regulation
in this subcategory.
nH can be controlled within the limits "of 7.5 to 10.0-with-
available Specific treatment methods and is therefore considered
for specific regulation in this subcategory >•
Ammonia , values were detected on all 78 sampling days. .The
maxtmum value detected was 120 mg/1 As many of^these valuesjjre
well above the treated effluent levels achievable with available
treatment methods, ammonia is considered f°VTif ^noUutant
subcategory. Ammonia's presence as a wastewater P°;^utant
results from the various materials used in casting and melting
operations.
Sulfide values were detected on all 63 sampling^ days. The
materials used
casting
pollutant is related to the various
and melting operations.
Fluoride values "wire" detected on all 63 sampling days in this
subcategory. The maximum level found was 242^mg/l,; As many of
IhesS values are well above the attainable treated effluent
levels, fluoride is considered for specific regulation in this
^category. Fluoride's presence as a wastewater pollutant is
associated with the fluxes used in melting operations. r -
Manganese values were detected on all 63 sampling ^days in ^this
subcategory. The maximum concentration detected was 392_mg/l.
many of these values are greater than the treated effluent
* attainable with available specific treatment .methods
manganese is considered for specific regulation in this
sSbcategory. Its presence is related to its use as an alloy.
Iron values were detected on 48 of the 49 sampl tng _ days _in this
subcategory. The maximum dissolved iron concentration detected
401
-------
was 26 mg/1. Iron is considered for specific regulation in this
subcategory, because it is the primary constituent of the
products of this subcategory.
Phenols values were detected on all 79 sampling days in this
subcategory. The maximum concentration found was 16.5 mg/1
Some of these concentrations are substantially above the optimum
expected 30-day average treated effluent levels achievable with
available treatment methods. This pollutant, detected by the
4-AAP wet chemistry technique, encompasses a variety of the
individual phenolic compounds. Its presence is related to the
raw materials used in the melting process and to the binders and
additives used in casting sand.
Pollutants Not Considered for Specific
Regulation in the Ferrous Casting Subcateqory
A total of one hundred and two pollutants that were evaluated
were eliminated from further consideration for specific
regulation in the ferrous casting subcategory. Twenty-six
pollutants were dropped from further consideration, because their
presence in raw process wastewaters was not detected.
Thirty-seven pollutants were eliminated from further
consideration, because the concentrations of these pollutants
were less than the analytically quantifiable limits.
The remaining thirty-nine pollutants were found to be present
infrequently, found at levels below those usually achieved bv
specific treatment methods, or present as a result of
site-specific conditions. Discussions of these pollutants
follow.
Benzene (4) concentrations appeared on 26 of 32 process sampling
days in the ferrous casting subcategory. The maximum
concentration was 0.361 mg/1. Seventeen concentrations are below
the level considered to be analytically quantifiable. Only one
of the remaining values is greater than the concentration
considered to be achievable with available specific treatment
methods. Therefore, benzene is not considered for specific
regulation in this subcategory.
Carbon tetrachloride (6) concentrations appeared on 14 of 32
process sampling days in the ferrous casting subcategory The
maximum concentration was 0.016 mg/1. Thirteen concentrations
are below the level considered to be analytically quantifiable.
The remaining value is lower than the concentration considered to
be achievable with available specific treatment methods.
Therefore, carbon tetrachloride is not considered for specific
regulation in this subcategory.
402
-------
1,2,4-trichlorobenzene (8) concentrations appeared on 6 of 32
process sampling days in the ferrous casting subcategory. The
Maximum concentration was O..30mg/l. Five concentrations are
below the level considered to be analytically quantifiable. Only
one concentration value is greater than the level considered -to
be achievable with available specific treatment methods.
Therefore., 1,2,4-trichlorobenzene is not considered for specific
regulation in this subcategory.
1 1 1,-trichloroethane (11) concentrations appeared on 18 of 32
process sampling days in the ferrous casting subcategory,. The
maximum concentration was 0.075 mg/1. Fourteen concentrations
are below the level considered to be analytically quantifiable.
The remaining values are all lower than the concentration
considered to be achievable with available specific treatment
methods. Therefore, 1,1,l-trichloroethane is not considered for
specific regulation in this subcategory.
Bis(2-chloroethyl) ether (18) concentrations appeared on 4 of 32
process sampling days in the ferrous casting subcategory. The
maxium concentration was 0.014 mg/1. Three concentrations are
below the level considered to be analytically quantifiable. The
remaining value is lower than the concentration considered to be
achievable with available specific treatment .methods. Therefore,
this toxic pollutant is not considered for specific regulation in
this subcategory.
2,4,6-trichlorophenol (21) concentrations appeared on 14 of 32
process, sampling days in the ferrous casting subcategory. The
maximum concentration was 0.195 mg/1. All but three of the
concentrations are below the level considered to be analytically
quantifiable. Therefore, 2,4,6-trichlorophenol is not considered
for specific regulation in this subcategory.
Parachlorometacresol (22) concentrations appeared on 8 ofJJ2
process sampling days in the ferrous casting subcategory. The
maximum conentration was 0.536 mg/1. Four concentrations are
less than the analytically quantifiable limit. Only two
concentrations are above the level considered to be achievable
with available specific treatment methods. Therefore,
parachlorometacresol is not considered for specific regulation, in
this subcategory. - - ( . ;
Chloroform (23) concentrations appeared on all 32 process
sampling days in the ferrous casting subcategory. The maximum
concentration was 0.692 mg/1. Sixteen concentrations are less
than the analytically quantifiable limit. Fifteen concentrations
are lower then that concentration considered to be achievable
403
-------
with available specific treatment methods. Therefore, chloroform
is not considered for specific regulation in this subcategory.
1,2,-trans-dichloroethylene (30) concentrations appeared on 1 of
32 process sampling days in the ferrous casting subcategorv.
That concentration was 0.033 mg/1. The concentration value is
lower than the concentration considered to be achievable with
available specific treatment methods, therefore,
1,2-trans-dichloroethylene is not considered for specific
regulation in this subcategory. »p«i.iiit.
1,3-dichloropropylene (33) concentrations appeared on 2 of 32
process sampling days in the ferrous casting subcategory. The
maximum concentration was 0.24 mg/1. Only one concentration
value is above that level considered to be achievable with
available specific treatment methods. Therefore,
1,3-dichloropropylene is not considered for specific regulation
in this subcategory.
Bis(2-chloroethoxy) 'methane (43) concentrations appeared on 6 of
32 process sampling days in the ferrous casting subcategorv. The
maximum concentration was 0.045 mg/1. Four concentrations are
below the level considered to be analytically quantifiable. All
conentration values are lower than the concentration considered
ThPrplnrf ihT! JS ."^available specific treatment methods.
Therefore, this toxic pollutant is not considered for specific
regulation in this subcategory.
Methylene chloride (44) concentrations appeared on 26 of 32
process sampling days in the ferrous casting subcategory The
maximum concentration was 2.05 mg/1. Twelve concentrations are
below the level considered to be analytically quantifiable. Only
two of the remaining concentrations are greater -than the level
considered to be achievable by specific treatment methods. Both
of those concentrations are from one plant. Therefore, methylene
cnionde is not considered for specific regulation in this
subcategory.
Methyl chloride (45) concentrations appeared on 1 of 32 process
sampling days in the ferrous casting subcategory The
concentration was 0.012 mg/1. Because this toxic pollutant was
found at only one plant, at a level lower than the concentration
considered to be achievable with available specific treatment
methods, methyl chloride is not considered for specific
regulation in this subcategory.
Bromoform (47)
sampling days
concentration was
concentrations appeared on 1 of 32 process
in the ferrous casting subcategory. The
0.018 mg/1. Because this toxic pollutant was
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found at ony one plant, at a level lower than the concentration
considered to be achievable with available specific treatment
methods, bromoform is not considered for specific regulation in
this subcategory.
Trichlorofluoromethane (49) concentrations appeared on 1 of 32
process sampling days in the ferrous casting subcategory. The
concentration was 0.12 mg/1. Because this toxic pollutant was
found at only one plant, at a level lower than the concentration
considered to be achievable with available specific treatment
methods, trichlorofluoromethane is not considered for specific
regulation in this subcategory.
Chlorodibromomethane (51) concentrations appeared on 1 of 32
process sampling days in the ferrous casting subcategory. The
concentration was 0.019 mg/1. Because this toxic pollutant was
found at only one plant, at a level lower than the concentration
considered to be achievable with available specific treatment
methods, Chlorodibromomethane is not considered for specific
regulation in this subcategory.
Isophorone (54) concentrations appeared on 10 of 32 process
sampling days in the ferrous casting subcategory. The maximum
concentration was 0.074 mg/1. Eight concentration values are
below the level considered to be analytically quantifiable. Only
one of the remaining concentration values is above the level
considered to be achievable by specific treatment methods'.
Therefore, this toxic pollutant is not considered for regulation
in this subcategory.
Naphthalene (55) concentrations appeared on 29 of 32 process
sampling days in the ferrous casting subcategory. The maximum
concentration was'0.13 mg/1. Seventeen concentration values are
below the level considered to be analytically quantifiable. Some
concentrations are above the level considered to be achievable
with available specific treatment methods. However, all of the
concentrations are below human toxicity levels. Therefore,
naphthalene is not considered for specific regulation in this
subcategory.
Nitrobenzene (56) concentrations appeared on 5 of 32 process
sampling days in the ferrous casting subcategory. The maximum
concentration was 0.86 mg/1. Three concentrations are less than
the analytically quantifiable limit. Only one of the remaining
two concentration values is above the level considered to be
achievable with available specific treatment methods. Therefore,
nitrobenzene is not considered for specific regulation in this
subcategory.
405
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2-nitrophenol (57) concentrations appeared on 15 of 32 process
sampling days in the ferrous casting subcategory. The maximum
concentration was 0.052 mg/1. Eleven concentrations are less
than the analytically quantifiable limit. Three of the four
remaining concentration values are less than the level considered
to be achievable by specific treatment methods. Only the maximum
concentration is at the level considered to be achievable with
available specific treatment methods. Therefore, 2-nitrophenol
is not considered for specific regulation in this subcategory.
4-nitrophenol (58) concentrations appeared on 7 of 32 process
sampling days in the ferrous casting subcategory. The maximum
concentration was 0.16 mg/1. Three concentrations are less than
the analytically quantifiable limit. Three of the remaining four
concentrations are less than the level considered to be
achievable by specific treatment methods. Only the maximum
concentration is above the level considered to be achievable with
available specific treatment methods. Therefore, 4-nitrophenol
is not considered for specific regulation in this subcategory.
Bis(2-ethylhexyl) phthalate (66) concentrations appeared on 31 of
32 process sampling days in the ferrous casting subcategory. The
maximum concentration was 0.42 mg/1. Ten concentration values
are below the level considered to be analytically quantifiable.
Many of the concentrations are above the level that is considered
achievable with available specific treatment methods. However,
all of the concentrations are below human toxicity levels.
Therefore, bis(2-ethylhexyl) phthalate is not considered for
specific regulation in this subcategory.
Di-n-butyl phthalate (68) concentrations appeared on 30 of 32
process sampling days in the ferrous casting subcategory. The
maximum concentration was 0.598 mg/1. Seventeen concentrations
are less than the analytically quantifiable limit. All of the
concentrations are below human toxicity levels. Therefore,
di-n-butyl phthalate is not considered for regulation in this
subcategory.
Di-n-octyl phthalate (69) concentrations appeared on 5 of 32
process sampling days in the ferrous casting subcategory. The
maximum concentration was 0.054 mg/1. Three concentrations are
less than the analytically quantifiable limit. Only two
concentrations are slightly above the level considered to be
achievable with specific treatment methods. Therefore,
di-n-octyl phthalate is not considered for specific regulation in
this subcategory.
Diethyl phthatlate (70) concentrations appeared on 24 of 32
process sampling days in the ferrous casting subcategory. The
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maximum concentration was 0.027 mg/1. Fourteen concentrations
are less than the analytically quantifiable limit. All other
concentrations are below human toxicity levels. Therefore,
diethyl phthalate is not considered for specific regulation in
this subcategory.
Dimethyl phthalate (71) concentrations appeared on 25 of 32
process sampling days in the ferrous casting subcategory. The
maximum concentration was 2.9 mg/1. Ten concentrations are less
than the analytically quantifiable limit. All other
concentrations are much lower than human toxicity levels.
Therefore, dimethyl phthalate is not considered for specific
regulation in.this subcategory.
3,4-benzofluoranthene (74) concentrations appeared on 2 of 32
process sampling days in the ferrous casting subcategory. The
maximum concentration was 0.019 mg/1. One concentration value is
below the level considered to be analytically quantifiable.
Because this toxic pollutant was found at only one plant,
3,4-benzofluoranthene is not considered for specific regulation
in this subcategory.
Benzo(k)fluoranthene (75) concentrations appeared on 2 of 32
process sampling days in the ferrous casting subcategory. The
maximum concentration was 0.018 mg/1. One concentration value is
below the level considered to be analytically quantifiable.
Because this toxic pollutant was found at only one plant,
benzo(k)fluoranthene is not considered for specific regulation in
this subcategpry.
Toluene (86) concentrations appeared on 20 of 32 process sampling
days in the ferrous casting, subcategory. The maximum
concentration was 0.015 mg/1. Fifteen concentrations are less
than the quantifiable limit. All other concentrations are below
the level that is considered to be achievable by specific
treatment methods. Therefore, toluene is not considered for
specific regulation in this subcategory.
Trichloroethylene (87) concentrations appeared on 18 of 30
process sampling days in the ferrous casting subcategory. The
maximum concentration was 0.77 mg/1. Eleven concentrations are
less than the analytically quantifiable limit. Six of the
remaining concentration values are below.the level considered to
be achievable with available specific treatment methods.
Therefore, trichloroethylene is not considered for specific
regulation in this subcategory.
Endrin aldehyde (99) concentrations appeared on 6 of 21 process
sampling days in the ferrous casting subcategory. The maximum
• 407
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concentration was 0.019 mg/1. Four concentrations are below the
analytically quantifiable limit. The other two concentrations
were found at the same plant. Therefore, endrin aldehyde is not
considered for specific regulation in this subcategory.
b-BHC-Beta (103) concentrations appeared on 10 of 21 process
sampling days in the ferrous casting subcategory. The maximum
concentration was 0.019 mg/1. Eight concentration values are
less than the analytically quantifiable limit. Because this
pollutant was found on only one process sampling day, b-BHC-Beta
is not considered for specific regulation in this subcategory.
Beryllium (117) concentrations appeared on 46 of 48 process
sampling days in the ferrous casting subcategory. The maximum
concentration was 0.04 mg/1. Forty-two concentrations are less
than the analytically quantifiable limit. All other
concentrations are below the level considered to be achievable
with available specific treatment methods. Therefore, beryllium
is not considered for specific regulation in this subcategory.
Cyanide (121) concentrations appeared on 67 of 69 process
sampling days in the ferrous casting subcategory. The maximum
concentration was 0.35 mg/1. Only three concentrations are above
the level considered to be achievable with available specific
treatment methods. Therefore, cyanide is not considered for
specific regulation in this subcategory.
Mercury (123) concentrations appeared on 56 of 57 process
sampling days in the ferrous casting subcategory. The maximum
concentration was 0.015 mg/1. Eighteen concentrations are below
the analytically quantifiable limit. All other concentrations
are below the level considered to be achievable with available
specific treatment methods. Therefore, mercury is not considered
for specific regulation in this subcategory.
Selenium (125) concentrations appeared on 25 of 27 process
sampling days in the ferrous casting subcategory. The maximum
concentration was 2.2 mg/1. Twenty-two concentrations are below
the analytically quantifiable limit. Two other concentrations
are below the level considered to be achievable with available
specific treatment methods. Therefore, selenium is not
considered for specific regulation in this subcategory.
Silver (126) concentrations appeared on 14 of 16 process sampling
days in the ferrous casting subcategory. The maximum
concentration was 0.11 mg/1. Nine concentrations are below the
analytically quantifiable limit. All other concentrations are at
or below the level considered to be achievable with available
408
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treatment methods. Therefore, silver is not considered for
specific regulation in this subcategory.
Thallium (127) concentrations appeared on 14 of. 16 process
sampling days in the ferrous casting subcategory. The maximum
concentration was 7.0 mg/1. Twelve concentrations are below the
analytically quantifiable limit. Because this pollutant was
found on only two process sampling days, thallium is not
considered for specific regulation in this subcategory.
Xylene (130) concentrations appeared on 7 of 28 process sampling
days in the ferrous casting subcategory. The maximum
concentration was 0.023 mg/1. Six concentration values are below
the analytically quantifiable limit. Because this pollutant was
found on only one sampling day, xylene is not considered for
specific regulation in this subcategory.
Lead Casting Subcategory
Pollutants Considered for Specific
Regulation .in the Lead Casting Subcateqory
Based on sampling results and careful examination of the _lead
casting subcategory manufacturing processes and raw materials,
six pollutants were selected for consideration for specific
regulation through effluent limitations and standards for this
subcategory. These pollutants were found in raw wastewaters from
processes in this subcategory and are amenable to control by
identified wastewater treatment practices (e.g., activated carbon
adsorption, chemical precipitation-sedimentation). Discussions
of these pollutants follow.
Copper was detected at a level of 0.046 mg/1 in the process
wastewaters sampled in this subcategory. Copper is used for
electrical conductors in charging operations and may be present
in process equipment. While it is not a primary raw material in
this subcategory, copper may be introduced into this
subcategory's process wastewaters by corrosion of equipment. ,
Lead was detected at a level of 0.85 mg/1 in the process
wastewaters sampled in this subcategory. This value is above the
level which can be achieved by specific treatment methods.
Zinc was detected at a level of 0.014 mg/1 in the process
wastewaters sampled in this subcategory. While it is not a
primary raw material in this subcategory, zinc may be introduced
into this subcategory's process wastewaters as a constituent of
the cast metal.
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Oil and grease was detected at a level of <5 mg/1 in the process
wastewaters sampled in this subcategory. This pollutant can be
removed by conventional treatment methods.
Suspended solids was detected at a level of 5 mg/1 in the process
wastewaters sampled in this subcategory. The TSS generated in
this subcategory may consist of large proportions of toxic
pollutants.
The pH of the process wastewaters sampled in this subcategory was
7.7. pH can be controlled within the limits of 7.5 to 10.0 with
available specific treatment methods.
Pollutants Not Considered for Specific
Regulation in the Lead Casting Subcategory
Analytical data for the lead casting subcategory was originally
collected as part of a study for the Battery Manufacturing Point
Source Category. The screening data for toxic organic pollutants
in this category demonstrated that these pollutants need not be
considered for specific regulation. As a result, analyses for
the toxic organic pollutants were not performed on the sampled
process wastewaters of this subcategory. As lead casting
operations are associated with the manufacture of lead-acid
batteries, data from the battery manufacturing category is
considered to be applicable to the lead casting subcategory. The
toxic organic pollutant dispositions presented in Tables VI-I
through VI-4 for the lead casting subcategory are based upon
battery manufacturing category data. Refer to the Battery
Manufacturing Point Source Category Development Document for
additional details on the sampling carried out at these
operations.
A total of one hundred thirty-one pollutants were eliminated from
further consideration for specific regulation in the lead casting
subcategory. Eighty-three pollutants were dropped from further
consideration, because their presence in raw process wastewater
was not detected. Thirty-one pollutants were eliminated from
further consideration, because the concentrations of these
pollutants were less than the analytically quantifiable limits.
i
The remaining seventeen pollutants were found to be present
infrequently, found at levels below those usually achieved by
specific treatment methods, or found only once.
The two toxic inorganic pollutants not considered for specific
regulation were detected at levels less than 0.003 mg/1 in the
process wastewaters sampled in this subcategory. These
410
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concentrations are
treatment methods.
below those levels achievable with specific
The five non-conventional pollutants not considered for specific
regulation were detected at the following levels in this
subcategory's sampled process wastewaters:
Ammonia(N)
Fluoride
Manganese
Iron
Phenol sUAAP)
0.05 mg/1
1.1 mg/1
0.005 mg/1
0.32 mg/1
0.012 mg/1
These concentrations are below those levels considered to be
achievable with specific treatment methods. Therefore, these
pollutants are not considered for specific regulation in., this
subcategory.
Seven of ten toxic organic pollutants not considered for specific
regulation were detected at levels considered to be
environmentally insignificant. The other three pollutants were
detected at levels below those considered to be achievable with
specific treatment methods. Refer to the Battery Manufacturing
Point Source Category Development Document for additional
details. j
Magnesium Casting Subcateqory
Pollutants Considered for Specific
Regulation in the Magnesium Casting Subcategory
Based on sampling results and a careful examination of the
magnesium casting subcategory manufacturing processes and raw
materials, seven pollutants were Selected for consideration for
specific regulation through effluent limitations and standards
for this subcategory. These pollutants were found in raw
wastewaters from processes in this subcategory and are amenable
to control by identified wastewater treatment practices (e.g.,
activated carbon adsorption, oxidation, chemical
precipitation-sedimentation). Discussions of these pollutants
follow.
Zinc (128) values were detected on all 6 sampling days in this
subcategory. The maximum concentration found was 1.7 mg/1. Some
of these concentrations are above the optimum expected 30-day
average treated effluent levels achievable with available
specific treatment methods. Contamination of process wastewaters
with this pollutant results from contact of process waters with
process equipment and facilities.
411
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Total suspended solids were found on all 6 sampling days in this
subcategory. The maximum concentration was 63 mg/1. Several of
the TSS concentrations are greater than the treated effluent
levels achievable with available treatment technologies.
Therefore, this pollutant is considered for specific regulation.
j-
Oil and grease values were found on all 6 sampling days in this
subcategory. The maximum concentration was 17 mg/1. As some of
the concentrations are greater than the treated effluent levels
typically achievable with available specific treatment methods,
oil and grease is considered for specific regulation in this
subcategory.
pH can be controlled within the limits of 7.5 to 10.0 with
available specific treatment methods, and is therefore
considered for specific regulation in this subcategory.
Sulfide values were detected on all 6 sampling days in this
subcategory. The maximum concentration was 21.0 mg/1. As some
of these values are greater than the treated effluent levels
attainable with specific treatment methods, sulfide is considered
for specific regulation in this subcategory.
Manganese values were detected on all 6 sampling days in this
subcategory. The maximum concentration was 0.42 mg/1. As
several of these values are greater than the treated effluent
levels achievable with available specific treatment in methods,
manganese is considered for specific regulation in this
subcategory.
Phenols values were detected on all 6 sampling days in this
subcategory. The maximum concentration found was 2.15 mg/1.
Some of these concentrations are above| the optimum expected
30-day average treated effluent levels achievable with available
treatment methods. This pollutant, detected by wet chemistry
techniques (4-AAP), encompasses a variety of the individual
phenolic compounds. Its presence is related to the various
casting sand additives and binders.
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Pollutants Not Considered for Specific
Regulation i_n the Magnesium Casting Subcateqory
A total of one hundred thirty pollutants that were evaluated were
eliminated from further consideration for specific regulation in
the magnesium casting subcategory. Seventy-one pollutants were
dropped from further consideration because their presence in raw
process wastewaters was not detected. Thirty-five pollutants
were eliminated from further consideration, because the
concentrations of these pollutants were less than the
analytically quantifiable limits.
The remaining twenty-four pollutants were found to be present
infrequently, found at levels below those usually • achieved by
specific treatment methods, or were,present as artifacts related
to sampling procedures. Discussions of these pollutants follow.
Acenaphthene (1) concentrations appeared on 2 of 6 process
sampling days in the magnesium subcategory.' The maximum
concentration was 0.064 mg/1. One of these two values is below
the quantification limit. Therefore, acenaphthene is not
considered for specific regulation in this subcategory.
BenzeneU) concentrations appeared on 1 of 6 process sampling
days in the magnesium subcategory. The ,maximum concentration was
0.014 mg/1. This is lower than the concentration considered to
be achievable with available specific treatment methods.
Therefore, benzene is not considered for specific regulation in
this subcategory.
Chloroform (23) concentrations appeared on all 6 process sampling
days in the magnesium subcategory. The maximum concentration was
0.016 mg/1. This is lower than the concentration considered to
be achievable with specific treatment methods. Therefore,
chloroform is not considered for specific regulation in this
subcategory.
2,4-dimethylphenol (34) concentrations appeared on 1 of 6 process
sampling days in the magnesium subcategory. The maximum
concentration was 0.016 mg/1. This is lower than the
concentration considered to be achievable with available specific
treatment methods. Therefore, 2,4-dimethylphenol is not
considered for specific regulation in this subcategory.
Methylene chloride (44) concentrations appeared on 4 of 6 process
sampling days in the magnesium subcategory. The maximum
concentration was 0.15 mg/1. All concentrations, except the
maximum value, were lower than the concentration considered to be
achievable with available specific treatment methods. The
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maximum concentration is only slightly above this level.
Therefore, with only one concentration above the level considered
to be achievable with available specific treatment methods,
methylene chloride is not considered for specific regulation in
this subcategory.
Pentachlorophenol (64) concentrations appeared on 1 of 6 sampling
days in the magnesium subcategory. The concentration was 0.033
mg/1. Since this concentration appeared on only one process
sampling day, pentachlorophenol is not considered for specific
regulation in this subcategory.
Phenol (65) concentrations appeared on 2 of 6 process sampling
days in the magnesium subcategory. The maximum concentration was
0.350 mg/1. All of the concentrations are much lower than the
human toxicity level, effects in humans. Therefore, phenol is
not considered for specific regulation in this subcategory.
Bis(2-ethylhexyl) phthalate (66) concentrations appeared on 5 of
6 process sampling days in the magnesium subcategory. The
maximum concentration was 0.195 mg/1. All concentrations are
much lower than the human toxicity level. Therefore,
bis(2-ethylhexyl) phthalate is not considered for specific
regulation in this subcategory.
Butyl benzyl phthalate (67) concentrations appeared on 4 of 6
process sampling days in the magnesium subcategory. The maximum
concentration was 0.013 mg/1. Three concentrations are below the
quantification limit. The maximum concentration is only slightly
above the level considered to be achievable with available
specific treatment methods. However, this maximum concentration
appeared on only one process sampling day. Therefore, butyl
benzyl phthalate is not considered for specific regulation in
this subcategory.
Di-n-butyl phthalate (68) concentrations appeared on 5 of 6
process sampling days in the magnesium subcategory. The maximum
concentration was 0.051 mg/1. Only one concentration is above
the level considered to be achievable with available specific
treatment methods. Therefore, di-n-butyl phthalate is not
considered for specific regulation in this subcategory.
Diethyl phthalate (70) concentrations appeared on 3 of 6 process
sampling days in the magnesium subcategory. The maximum
concentration was 0.20 mg/1. Two concentrations are below the
quantification limit. All of the concentrations are lower than
the human toxicity level. Therefore, diethyl phthalate is not
considered for specific regulation in this subcategory.
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Dimethyl phthalate (71) concentrations appeared on 2 of 6 process
sampling days in the magnesium subcategory. The maximum
concentration'was 1.1 mg/1. All concentrations are lower than
the human toxicity level. Therefore, dimethyl phthalate is not
considered for specific regulation in this subcategory.
Chrysene (76) concentrations appeared on 3 of 6 process sampling
days in the magnesium subcategory. The maximum concentration was
0 016 mg/1. Two concentrations are below the quantification
limit. The maximum concentration appeared on only one process
sampling day. Therefore, chrysene is not considered for specific
regulation in this subcategory.
Acenaphthylene (77.) concentrations appeared on 5 of 6 process
sampling days in the magnesium subcategory. The maximum
concentration was 0.124 mg/1. Four concentrations are below the
quantification limit. The maximum concentration appeared on only
one process sampling day. Therefore, acenaphthylene is not
considered for specific regulation in this subcategory.
Anthracene (78) concentrations appeared on 5 of 6 process
sampling days in the magnesium subcategory. The maximum
concentration was 0.10 mg/1. Four concentrations are below the
quantification limit. The maximum concentration appeared on only
one process sampling day. Therefore, anthracene is not
considered for specific regulation in this subcategory.
Phenanthrene (81) concentrations appeared on 5 of 6 process
sampling days in the magnesium subcategory. The maximum
concentration was 0.10 mg/1. Four concentrations are below the
quantification limit. The maximum concentration appeared on only
one process sampling day. Therefore, phenanthrene is not
considered for specific regulation in this subcategory.
Pyrene (84) concentrations appeared on 4 of 6 process sampling
days in the magnesium subcategory. The maximum concentration was
0 019 mg/1. Three concentrations are below the quantification
limit. The maximum concentration appeared on only one process
sampling day. Therefore, pyrene is not considered for specific
regulation in this subcategory.
Toluene (86) concentrations appeared on 3 of 6 process sampling
days in the magnesium subcategory. The maximum concentration was
0 030 mg/1. This is lower than the concentration considered to
be achievable with available specific treatment methods.
Therefore, toluene is not considered for specific regulation in
this subcategory.
.'-'415
-------
Copper (120) concentrations appeared on all 4 process sampling
days in the magnesium subcategory. The maximum concentration was
0.08 mg/1. All concentrations are below the level considered to
be achievable with available specific treatment methods.
Therefore, copper is not considered for specific regulation in
this subcategory.
i
Cyanide (121) concentrations appeared on all 6 process sampling
days in the magnesium subcategory. The maximum concentration was
0.01 mg/1. All concentrations are below the level considered to
be achievable with available specific treatment methods.
Therefore, cyanide is not considered for specific regulation in
this subcategory.
Lead (122) concentrations appeared on all 6 process sampling days
in the magnesium subcategory. The maximum concentration was 0.13
mg/1. All concentrations are below the level considered to be
achievable with available treatment methods. Therefore, lead is
not considered for specific regulation in this subcategory.
Ammonia concentrations appeared on all 6 process sampling days in
the magnesium subcategory. The maximum concentration was 2.1
mg/1. This concentration is lower than the human toxicity level.
Therefore, ammonia is not considered for specific regulation in
this subcategory.
Fluoride concentrations appeared on all 6 process sampling days
in the magnesium subcategory. The maximum concentration was 2.5
mg/1. All concentrations are below the level considered to be
achievable with available treatment methods. Therefore, fluoride
is not considered for specific regulation in this subcategory.
Iron concentrations appeared on all 5 process sampling days in
the magnesium casting subcategory. The maximum concentration was
0.06 mg/1. Two of the concentration values are below the level
considered to be analytically quantifiable. All of the
concentration values are below that level considered to be
achievable by specific treatment methods. Therefore, iron is not
considered for specific regulation in this subcategory.
Zinc Casting Subcateqory
Pollutants Considered for Specific
Regulation in the Zinc Casting Subcategory
Based upon sampling results and a careful examination of the zinc
casting subcategory manufacturing processes and raw materials,
seventeen pollutants were selected for consideration for specific
regulation through effluent limitations and standards for this
416
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subcategory. These pollutants "were found in the^raw^ wastewaters
from processes in this subcategory and are amenable to control by
wastewater treatment practices (e.g., activated carbon
adsorption, chemical precipitation-sedimentation). Discussions
of these pollutants follow.
2,4,6-trichlorophenol (21) values were detected on 7 of the 11
sampling days in this subcategory. The maximum concentration
found was 2.65 mg/1. Some of these concentrations are^above the
optimum expected 30-day average treated effluent levels
achievabl! with available treatment methods. This pollutant's
presence can be related to its use as an agent to control
biological growth in various process solutions and to the use of
"dirty scrap" in the furnace change.
Parachlorometacresol ( 22 ) values were detected on 6 of the_ 1 1
sampling days in this subcategory. The maximum concentration
found was 0.40 mg/1. Some of concentrations are above the
treated effluent levels achievable with available specific
treatment methods. This pollutant's presence can be related to
the process solutions used in this subcategory.
2,4-dichlorophenol (~31 ) values were detected on 7 of the _ 11
sampling days in this subcategory. The maximum concentration
found was 1.95 mg/1. Some of the concentrations are above the
treated effluent levels achievable with available specific
treatment methods. This pollutant's presence can be related to
the use, of "dirty" scrap in the furnace charge.
2, 4-dimethylphenol (34) values were detected on 10 of the^ _ l l
sampling days in this subcategory. The maximum concentration
found was 9.3 mg/1. Some of these concentrations are well above
the optimum expected 30-day average treated effluent levels
achievable with available treatment methods. The presence of
this pollutant can be related to its use as a solvent and a
biological growth control agent in this subcategory 's process
solutions, and to the use of "dirty scrap" in the furnace charge.
Naphthalene (55) values were detected on 7 of the 11 sampling
days in this subcategory. The maximum concentration found was
4 0 ma/1. Some of the concentrations are above the treated
effluent levels achievable with available specific treatment
methods. The presence of this pollutant can be related to the
use of "dirty" scrap in the furnace charge.
Phenol (65) values were detected on 1 0 of the 11 sampling days in
this subcategory. The maximum concentration found was 19.0 mg/l.
Some of these concentrations, are substantially above the ^optimum
expected 30-day average treated effluent levels achievable with
417
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available treatment methods. This pollutant's presence can be
related to various process solutions and to contaminants in the
scrap charge to the melting process.
Butyl benzyl phthalate (67) values were detected on 5 of the 11
sampling days in this subcategory. The maximum concentration
found was 0.12 mg/1. Some of the concentrations are above the
treated effluent levels achievable with available specific
treatment methods. This pollutant's presence can be related to
the use of contaminated scrap in the furnace charge.
Pyrene (84) values were detected on 8 of the 11 sampling days in
this subcategory. The maximum concentration found was 0.018
mg/1. Some of the concentrations are above the treated effluent
levels achievable with available specific treatment methods.
This pollutant can be found in process solutions (e.g.,
diecasting and casting quench solutions).
Tetrachloroethylene (85) values were detected on 7 of the 11
sampling days in this subcategory. The maximum concentration
found was 0.142 mg/1. Some of these concentrations are above the
optimum expected 30-day average treated effluent levels
achievable with available treatment methods. This pollutant's
presence can be related to solutions used in this subcategory's
processes.
Lead (122) values were detected on all 11 sampling days in this
subcategory. The maximum concentration found was 0.42 mg/1.
Some of these concentrations are above the optimum expected
30-day average treated effluent levels achievable with available
treatment methods. The presence of this pollutant is related to
its use in process equipment and facilities and to its presence
in the cast metal.
Zinc (128) values were detected on all 11 sampling days in this
subcategory. The maximum concentration found was 350 mg/1. Some
of the concentrations are above the treated effluent levels
achievable with available specific treatment methods. Zinc is
considered for specific regulation in this subcategory as it is
the major metal cast.
Total suspended solids were found on all 11 sampling days in this
subcategory. The maximum concentration found was 3,800 mg/1.
The TSS concentrations are greater than the treated effluent
levels achievable with available specific treatment methods. In
addition, control of TSS in process wastewater discharges will
result in the control, to a certain extent, of several toxic
pollutants.
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Oil and grease values were found on all 11 sampling days in this
subcategory. The maximum concentration found was 17,100 mg/1.
These oils and greases originate as process wastewater
pollutants, in the solutions, products, and scrap used in this
subcategory's processes. As many of the concentrations are
greater than the treated effluent levels typically achievable,
oil and grease is considered for specific regulation in this
subcategory.
pH can be controlled within the limits of 7.5 to 10.0 with
available specific treatment methods and is therefore considered
for specific regulation in this subcategory.
Sulfide values were detected on all 11 sampling days in this
subcategory. The maximum concentration found was 1.0 mg/1. As
several of the concentrations are greater than the treated
effluent levels attainable with available specific treatment
technologies, sulfide is considered for specific regulation in
this subcategory.
Manganese values were detected on all 11 sampling days in this
subcategory. The maximum concentration found was 0.29 mg/1. As
several of these values are greater than the treated effluent
levels achievable with available specific treatment methods,
manganese is considered for specific regulation in this
subcategory.
Phenols values were detected on all 11 sampling days in this
subcategory. The maximum concentration found was 123 mg/1. Some
of these concentrations are substantially above the optimum
expected 30-day average treated effluent levels achievable with
available treatment methods. This pollutant, detected by wet
chemistry techniques (4AAP), encompasses a variety of the
individual phenolic compounds. This pollutant results from the
process solutions used in this subcategory and from contaminants
in the furnace scrap charge.
Pollutants Not Considered for Specific
Regulation in the Zinc Casting Subcategory
A total of one hundred twenty pollutants that were evaluated were
eliminated from further consideration for specific regulation in
the zinc casting subcategory. Fifty pollutants were dropped from
further consideration, because their presence in raw process
wastewaters was not detected. Thirty-five pollutants were
eliminated from further consideration, because the concentrations
of these pollutants were less than the analytically quantifiable
limits. ; '": ; ,
419
-------
The remaining thirty-five pollutants were found to be present
infrequently or found at levels below those typically achieved by
specific treatment methods. Discussions of these pollutants
follow.
Acenaphthene (1) concentrations appeared on 4 of 11 process
sampling days in the zinc casting subcategory. The maximum
concentration was 2.5 mg/1. Two concentrations are less than the
analytically quantifiable limit. The maximum concentration is
the only value above the level achievable with available specific
treatment methods. Because this concentration level is found
only on 1 of 11 process sampling days, acenaphthene is not
considered for specific regulation in this subcategory.
Benzene concentrations appeared on 5 of 11 process sampling days
in the zinc casting subcategory. The maximum concentration was
0.15 mg/1. Four of these concentrations are less then the
analytically quantifiable limit. As a quantifiable concentration
was found on only one sampling day, benzene is not considered for
specific regulation in this subcategory.
Carbon tetrachloride (6) concentrations appeared on 4 of 11
process sampling days in the zinc casting subcategory. The
maximum concentration was 0.029 mg/1, which is less than the
concentration achievable by specific treatment methods. Three
concentrations are below the analytically quantifiable limit.
Therefore, this toxic pollutant is not considered for specific
regulation in this subcategory.
1,2,4-trichlorobenzene (8) concentrations appeared on 1 of 11
process sampling days in the zinc casting subcategory. The
concentration was 3.15 mg/1. Because this toxic pollutant is
found at only one plant, it is not considered for specific
regulation in this subcategory.
1r 1,1-trichloroethane (11) concentrations appeared on 3 of 11
process sampling days in the zinc casting subcategory. The
maximum concentration was 0.044 mg/1. This concentration is
lower than the concentration considered to be achievable with
available specific treatment methods. Two concentrations are
below the analytically quantifiable limit. Therefore, this
pollutant is not considered for specific regulation in this
subcategory.
i
Chloroform (23) concentrations appeared on all 11 process
sampling days in the zinc casting subcategory. The maximum
concentration was 0.067 mg/1. This concentration is lower than
the concentration considered to be achievable with available
specific treatment methods. Ten concentrations are below the
420
-------
analytically quantificable limit. Therefore, this pollutant: is
not considered for specific regulation in-this subcategory.
2-chlorophenol(24) concentrations appeared on 3 of 11 sampling
days in the zinc casting subcategory. The maximum concentration
was 0.21 mg/1. One concentration is below the analytically
quantifiable limit. Another concentration is below the level
considered to be achievable with available specific treatment
methods. Therefore, 2-chlorophenol is not considered for
specific regulation in this subcategory.
1,2-trans-dichloroethylene (30) concentrations appeared on 1 of
11 process sampling days in the zinc casting subcategory. The
concentration was 0.043 mg/11. Because this toxic pollutant is
found at only one plant, and the concentration is lower than the
concentration considered to be achievable with available specific
treatment methods, this pollutant is not considered for specific
regulation in this subcategory.
2,4-dinitrotoluene (35) concentrations appeared on 1 of 11
process sampling days in the zinc casting subcategory. The
concentration was 0.11 mg/1. Because this pollutant is present
at only one plant, it is not considered for specific regulation
in this subcategory.
2,6-dinitrotoluene (36) concentrations appeared on 1 of 11.
process sampling days in the zinc casting subcategory. The
maximum concentration was 0.11 mg/1. Because this pollutant is
present at only one plant, it is not considered for specific
regulation in this subcategory.
Ethylbenzene (38) concentrations appeared on 2 of 11 process,
sampling days in the zinc casting subcategory. The maximum
concentration was 0.018 mg/1. This concentration is lower than
the concentration considered to be achievable with available
specific treatment methods. One concentration is below the
analytically quantifiable limit. Therefore, this pollutant is
not considered for specific regulation in this subcategory.
Fluoranthene (39) concentrations appeared on 6 of 11 process
sampling days in the zinc casting subcategory. The maximum
concentration was 0.029 mg/1. Two concentrations are below the
analytically quantifiable limit. Four of the concentrations are
slightly greater than the level considered to be achievable by
specific treatment methods. However, all of these concentrations
are much lower than the human toxicity level. Therefore,
fluoranthene is not considered for specific regulation in this
subcategory.
421
-------
Methylene chloride (44) concentrations appeared on 7 of 11
process sampling days in the zinc casting subcategory. The
maximum concentration was 0.30 mg/1. Four concentrations are
below the analytically quantifiable limit. Another concentration
is lower than the concentration considered to be achieved with
available specific treatment technology. Therefore, methylene
chloride is not considered for specific regulation in this
subcategory.
Nitrobenzene (56) concentrations appeared on 1 of 11 process
sampling days in the zinc casting subcategory. The concentration
was 0.21 mg/1. Becaus.e this toxic pollutant is present at only
one plant, nitrobenzene is not considered for specific regulation
in this subcategory.
4-nitrophenol (58) concentrations appeared on 1 of 11 process
sampling days in the zinc casting subcategory. The concentration
was 1.6 mg/1. Because this toxic pollutant is present at only
one plant, 4-nitrophenol is not considered for specific
regulation in this subcategory.
I
i
2,4-dinitrophenol (59) concentrations appeared on 2 of 11 process
sampling days in the zinc casting subcategory. The maximum
concentration was 0.09 mg/1. One concentration is below the
analytically quantifiable limit. Therefore, 2,4-dinitrophenol is
not considered for specific regulation in this subcategory.
Bis(2-ethylhexyl) phthalate (66) concentrations appeared on all
11 process sampling days in the zinc casting subcategory. The
maximum concentration was 4.3 mg/1. Many of the concentrations
are greater than those considered to be achievable with available
specific treatment methods. However, all of the concentrations
are much lower than the human toxicity level. to cause toxic
effects in humans. Therefore, bis(2-ethylhexyl) phthalate is not
considered for specific regulation in this subcategory.
Di-n-butyl phthalate (68) concentrations appeared on all 11
process sampling days in the zinc casting subcategory. The
maximum concentration v/as 0.30 mg/1. Many of the concentrations
are greater than those considered to be achievable with available
specific treatment methods. However, all of the concentrations
are much lower than the human toxicity level. Therefore,
di-n-butyl phthalate is not considered for specific regulation in
this subcategory.
Di-n-octyl phthalate (69) concentrations appeared on 1 of 11
process sampling days in the zinc casting subcategory. The
concentration was 2.8 mg/1. Because this toxic pollutant is
422
-------
present at only one plant, di-octyl phthalate is not considered
for specific regulation in this subcategory.
Diethvl phthalate (70) concentrations appeared on 6 of 11 process
sampling days in the zinc casting subcategory. The maximum
c1ncen?ra??on was 13.0 mg/1. Many of the concentrations ape
greater than those considered to be achievable with available
specific treatment methods. Two concentrations are below the
analytically quantifiable limit. However, all ^of the
concentrations are much lower than the human toxicity level,
TherJfore, diSthyl phthalate is not considered for specific
regulation in this subcategory.
Dimethyl pthalate (71) concentrations appeared on 3 ofjl process
sampling days in the zinc casting subcategory. The maximum
concentration was 0.13 mg/1. One concentration is below the
analytically quantifiable limit. All of the concentrations are
Slower than the human toxicity level Therefore dimethyl
phthalate is not considered for specific regulation in this
subcategory.,
Benzo(a)anthracene (72) concentrations appeared^ on 2 of 11
process sampling days in the zinc casting subcategory. The
m^imum concentration was 0.075 mg/1 One Concentration is below
the analytically quantifiable limit. Because this toxic
pollutant is present at only one plant, benzo
-------
achievable with available specific treatment methods, fluorene is
not considered for specific regulation in this subcategory.
Toluene (86) concentrations appeared on 4 of 11 process sampling
days in the zinc casting subcategory. The maximum concentration
was 0.027 mg/1. All concentrations are lower than the
concentrations considered to be achievable with available
specific treatment methods. Two concentrations are below the
analytically quantifiable limit. Therefore, toluene is not
considered for specific regulation in this subcategory.
Trichloroethylene (87) concentrations appeared on 5 of 11 process
sampling days in the zinc casting subcategory. The maximum
concentration was 0.23 mg/1. Three concentrations are below the
analytically quantifiable limit. One concentration is lower than
fu fvel considered achievable with available specific treatment
methods. Because this toxic pollutant is found on only one
process sampling day at a level considered to be achievable with
available specific treatment methods, trichloroethylene is not
considered for specific regulation in this subcategory
Cyanide (121) concentrations appeared on all 11 process sampling
ys « A., ,?inc castin9 subcategory. The maximum concentration
was 0.02 mg/1. All concentrations are lower than level
considered to be achievable with available specific treatment
methods. Therefore, cyanide is not considered for specific
regulation in this subcategory.
Copper (120) concentrations appeared on all 8 process sampling
days in the zinc casting subcategory. The maximum concentration
was 0.20 mg/1. Two concentrations are lower than the
analytically quantifiable limit. Five concentrations are lower
than the concentrations considered to be' achievable with
available specific treatment methods. Because this toxic
pollutant is found on only one process sampling day at a level
considered to be achievable with available specific treatment
methods, copper is not considered for specific regulation in this
subcategory.
Mercury (123) concentrations appeared on all 8 process sampling
days in the zinc casting subcategory. The maximum concentration
was 0.0012 mg/1. All concentrations are lower than the
concentrations considered to be achievable with available
specific treatment methods. Therefore, cyanide is not considered
for specific regulation in this subcategory.
Nickel (124) conentrations appeared on all 8 process sampling
days in the zinc casting subcategory. The maximum concentration
was 0.04 mg/1. Seven concentrations are lower than the
424
-------
analytically quantifiable limit. Because this toxic pollutant is
Toun* on only^ne process sampling day at a level ^considered to
be achievable with available specific treatment methods, nicKei
is not considered for specific regulation in this subcategory.
Xvlene (130) concentrations appeared on 2 of 9 process sampling
dayf in the zinc casting subcategory. The^ maximum concentration
was 0 12 mq/1. Three concentrations are below the analytically
Quantifiable Umit. The maximum concentration is less than the
human toxic! ty level. Therefore, xyleneis not considered for
specific regulation in this subcategory.
Ammonia concentrations appeared on 'all 1 1 process sampling days-
in >he zinc casting subcategory. The maximum concentration was
2 4 mq/1 All concentrations are lower than the level considered
a SS.
Therefore, fluoride is not considered for specific regulation in
this subcategory.
iron concentrations appeared on all 11 process samP^n?ft nd^J 6in,
the zinc casting subcategory. The maximum concentration was 6.9
ma/1 Eight of the concentration values are above the levels
considered to be achievable by specific treatment methods An
Examination of the melting furnace scrubber and_the. di « casting •
and casting quench processes, however, indicates that tne
oresence of this pollutant cannot be directly attributed to these
^rScSsSes9 Thlrlfore, iron is , not considered for specific
regulation in this subcategory.
Summary
Table VI-4 presents a summary of the toxic pollutant
dispositions, by subcategory, discussed previously in this
section Table VI-5 presents a summary of the conventional and
nln-cSnventi rial pollutant dispositions for each subcategory
While these two tables list the various pollutants considered for
specific reflation in each subcategory, Table VI-6 Presents a
Summary of those toxic, conventional, and non-conventional
ooTTutants considered for specific regulation in each process
legmen? The e pollutants were considered for regulation on the
balis of- plant assessments of a pollutant's presence (refer to
Section V) - engineering assessments -of a pollutant's presence
(refe? to Section V); and the sampled plant analytical data with
425
-------
;t
segment. regulation in each subcategory and
process
426
-------
, TABLE VI-1
TOXIC POLLUTANTS NOT DETECTED IN THE METAL
MOLDING AND CASTING CATEGORY
Pollutant
Number
002
003
012
016
017
019
028
029
032
040
041
042
046
050
052
053
061
079
082
083
088
116
129
Pollutant
Name
Acrolein
Acrylonitrile
Hexachloroethane
Chioroethane
bis-(chloromethyl) ether
2-chloroethyl vinyl ether
3,3'-dichlorobenzidine
1,1-dichloroethylene
1,2-dichloropropane
4-chlorophenyl phenyl ether
4-bromophenyl phenyl ether
bis-(2-chloroisopropyl)ether
Methyl bromide
Dichlorodifluoromethane
Hexach1orobutadiene
Hexachlorocyclopentadiene
N-nltrosodimethylamine
Benzo (g,h,i) perylene
Dibenzo (a,h) anthracene
Indeno (Ij2,3,-cd) pyrene
Vinyl chloride
Asbestos
2,3,7,8-te trachlorodibenzo-p-
dioxin (TCDD)
427
-------
TABLE VI-2
TOXIC POLLUTANTS DETECTED BELOW QUANTIFIABLE
LIMITS IN THE METAL MOLDING AND CASTING CATEGORY
Pollutant
Number
009
020
025
026
027
037
090
094
095
096
097
098
100
113
Pollutant
Name
Hexachlorobenzene
2-chloronaphthalene
1> 2-dichlorobenzene
1> 3-dichlorobenzene
1,4-dichlorobenzene
1> 2-diphenylhydrazine
Dieldrin
4,4'-ODD
a-endosulfan-Alpha
b-endosulfan-Beta
Endosulfan sulfate
Endrin
Heptachlor
Toxaphene
428
-------
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TABLE VI-5
CONVENTIONAL AND NON-CONVENTIONAL POLLUTANT DISPOSITION
METAL MOLDING AND CASTING CATEGORY
Subcategory
Pollutant
TSS
Oil & Grease
PH
Ammonia (N)
Sulfide
Fluoride
Manganese
Iron
Phenols (4AAP)
Xylene
Aluminum
Casting
REG
REG
REG
REG
REG
NT
NT
NT
REG
REG
Copper
Casting
REG
REG
REG
NT
NT
NT
REG
NT
REG
NT
Ferrous
Casting
REG
REG
REG
REG
REG
REG
REG
REG
REG
NT
Lead
Casting
' REG
REG
REG
NT
NQ
NT
NT
NT
NT
' NT
Magnesium
Casting
REG
REG
REG
NT
REG
NT
REG
NT
REG
NT
Zinc
Casting
REG
REG
REG
NT
REG
NT
REG
NT
REG
NT
.LEGEND:
ND :
NQ :
NT :
REG:
Not detected
Not quantifiable
Not treatable by the end-of-pipe
technologies considered or found only once.
Considered for regulation
436
-------
. TABLE VI-6
TOXIC, CONVENTIONAL AND NON-CONVENTIONAL POLLUTANTS
CONSIDERED FOR REGULATION IN THE METAL MOLDING AND "CASTING CATEGORY
Aluminum
Pollutant
001 Acenaphthene
005 Benzidine
006 Carbon tetrachloride
007 Chlorobenzene
010 1,2-dichloroethane
Oil 1,1,1-trichloroethane
013 1,1-dichloroethane •
021 2,4,6-trichlorophenol
022 Parachlorometa crespl
023 Chloroform
024 2-chlorophenol
031 2,4-dichlorophenol
034 2,4-dimethylphenol .
039 Fluoranthene
044 Methylene chloride
055 Naphthalene
058 4-nitrophenol
059 2,4-dinitrophenol
060 4,6-dinitro-o-cresol
062 N-nitrosodiphenylamine
063 N-nitrosodi-n-propylamine
064 Pentachlorophenol
065 Phenol
066 bis(2-ethylhexyl)phthalate
067 Butyl benzyl phthalate
072 Benzo(a)anthracene
073 Benzo(a)pyrene
074 3,4-benzofluoranthene
075 Benzo(k)fluoranthane
076 Chrysene
077 Acenaphthylene
078 Anthracene
080 Fluorene
081. Phenanthrene
084 Pyrene
085 Tetrachloroethylene
087 Trichloroethylene
091 Chlordane
114 Antimony '
115 Arsenic
118 Cadmium
119 Chromium
120 Copper
122 Lead
124 Nickel ' ', .
128 Zinc
Ammonia (N)
Fluoride
Iron
Manganese
Oil & Grease
Phenols (4AAP)
Sulfide
TSS
Xylene
pH
Melting
Investment Furnace Die
Casting Scrubber Casting
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X
-
Die
Lube
_
X
X
X
X
X
X
X
-
X
- :
X
X
X
X
X
X
X
X
X
:
_
X
X
X
X
X .
X
X
X
X
X
Copper
Mold
Cooling
"And
Dust Casting
Collection Quench
437
-------
TABLE VI-6
TOXIC, CONVENTIONAL AND NON-CONVENTIONAL POLLUTANTS CONSIDERED
FOR REGULATION IN THE METAL MOLDING AND CASTING CATEGORY
PAGE 2
Ferrous
Dust
Pollutant Collection
001
005
006
007
010
Oil
013
021
022
023
024
031
034
039
044
055
058
059
060
062
063
064
065
066
067
072
073
074
075
076
077
078
080
081
084
085
087
091
114
115
118
119
120
122
124
128
Acenaphthene
Benzidine
Carbon tetraehloride
Chlorobenzene
1,2-dichloroethane
1,1, 1-trichloroethane
1 , 1-dichloroethane
2,4, 6-tr ichlorophenol
Parachlorometa cresol
Chloroform
2-chlorophenol
2,4-dichlorophenol
2,4-dinethylphenol
Fluoranthene
Kethylene chloride
Naphthalene
4-nitrophenol
2,4-dinitrophenol
4,6-dinitro-o-cresol
N-nitrosodiphenylamine
n-nitroaodi-n-propylamine
Pentachlorophenol
Phenol
bi»(2-ethylhexyl)phthalate
Butyl benzyl phthalate
Benzo{a)anthracene
Benzo(a)pyrene
3 ,4-benzo£luoranthene
Benzo(k) f luoranthane
Chrysene
Acenaphthylene
Anthracene
Fluorene
Phenanthrene
Pyrene
Tetrachloroethylene
Trichloroethylene
Chlordane
Antimony
Arsenic
Cadmium
Chromium
Copper
Lead
Nickel
Zinc
Aaoonia (N)
Fluoride
Iron
Manganese
Oil & Grease
Phenols (4AAP)
Sulfide
TSS
Xylene
pH
X
X
X
X
X
X
X
_
X
X
-
_
_
X
X
_
X
X
X
X
_
—
-
-
_
-
X
X
X
X
X
-
X
X
X
X
X
X
-
X
Melting
Furnace Slag
Scrubber Quench
X
X
X
X
X
X
X
X
X
X
X
_
_
_
X
X
_
X
X
X
X
_
_
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
-
X
X
X
_
X
_
_
_
_
_
„
_
„
_
-
_
X
_
_
-
X
X
X
X
X
X
X
X
X
X
X
X
X
X
-
X
Mold
Cooling
And
Casting
Quench
i
_
_
„
_
_
_
_
_.
_
_
„
_
_
_
_
_
_
_
_
_
_
_
_
_
-
_
_
X
X
_
X
_
X
Lead
Melting
Sand Continuous Furnace Grid
Washing Strip Casting Scrubber Castine
X
_
X
„
_.
_
_. :
_
— '
X
_
„
X '
_ ;
_
_ '
_ ;
_ !
X
X
X
x ;
X
x
X
x
X
X •
X
X
X
-
..
_
_
_
_
_
_
_
_
_
_
_
_
_
—
_
_
_
_
_
_
X
x
X
_
_
_
x
_
X
X
-
_.
_
_
_
_
_
_
_
_
_
_
_
_
^
_
_
_
_
X
x
X
_
_
x
_
X
X
_
_
_
_
_
_
_
_
x
x
X
_
x
x
X
438
-------
TABLE VI-6 ~ . - -. '
TOXIC, CONVENTIONAL AND NON-CONVENTIONAL POLLUTANTS CONSIDERED
FOR REGULATION IN THE METAL MOLDING AND CASTING CATEGORY
PAGE 3
Magnesium
Pollutant
001
005
006
007
010
Oil
013
021
022
023
024
031
034
039
044
055
058
059
060
062
063
064
065
066
067
072
073
074
075
076
077
078
080
081
084
085
087
091
114
115
118
119
120
122
124
128
Acenaphthene
Benzidine
Carbon tetrachloride
Chlorobenzene,
1,2-dichloroethane
1,1, 1-trichloroethane
1 , 1-dichloroethane
2,4 , 6-trichlorophenol
Parachlorometacresol
Chloroform ' -r_- ' -
2-chlorophenol
2,4-dichlorophenol
2 , 4-dimethy Iphenol
Fluoranthene
Methylene chloride
Naphthalene
4-nitrophenol
2 , 4-dinitrophenol
4,6-dinitro-o-cresol
N-nitrosodiphenylamine
n-nitrosodi-n-propylamine
Pentachlorophenol
Phenol
bis(2-ethylhexyl)phthalate
Butyl benzyl phthalate
Benzo( a ) anthracene
Benzo(a)pyrene
3,4-benzof luoranthene
Benzo(k) f luoranthane
Chrysene
Acenaphthylene , .,
Anthracene
Fluorene
Phenanthrene
Pyrene
Tetrachloroethylene
Trichloroethylene
Chlordane
Antimony
Arsenic
Cadmium
Chromium -
Copper
Lead
Nickel -. . -. '
Zinc .. -
Ammonia (N)
Fluoride
Iron
Manganese
Oil & Grease
Phenols (4AAP)
Sulfide "••-•; ''
TSS
Xylene . . • .
pH
Dust
Collection
_
-
'
-
-
-
-
'.
-
' ,' .-.;;
"
.
-
-
V
- ••
-
-
-
-
-
-
-
.
-
-
...... ..._...
-
-
-
- . .
-
-
-
- •
-
-
- - "
-
„•.'. ; -.
]: -
-
-
-
- 1 -
, '- X
-'--*--
-
-
-
.. X
X
•--,- • -- x
x .
'. -"••-"'-.'--
~ X
Grinding
Scrubber
_
-,
-
-•
-'
-
-
-
-
. " -',
-,
-
- L
-
-
~
_
~ ..
~
-
~
~
-
-
-
~
_. ., ...
-
~
~
-
~
-
-
-
-
-
_' ' "
-
.".,-,-
,-
-
-
-
-
X
-;
-
-
X
X
-
- •
X
X
Casting
Quench
_
._
-
-
-
-
X
X
.". " " -
. . 1 - .
-
.
,
-"
-
-
—
-
. -
-
-
-
-
-
-
_
-
-
-
-
-
-
-
X
X
-
... -
-
-
"
-
-
X
'-.
X
-
r-
-
X
X
X
X
X
-
X
Zinc
Melting
Furnace
Scrubber
-
-
- •
• -
- -
-
-
X
X
'. '
-
X
. X
.
-
X
-
—
-
-
-
-
X
-
X
-
_
-
-
-
—
-
-
-
-
—
~
-
-
-
-
-
-
-
-
X
. ". -
-
-
-
X
X
-
X
' . -
X
Pollutant considered for regulation.
Pollutant not considered for regulation.
439
-------
-------
SECTION VII
..CONTROL AND TREATMENT TECHNOLOGY
INTRODUCTION
This section describes the treatment techniques currently in use
or available to remove or recover the wastewater pollutants
generated by metal molding and casting processes. Included are
discussions of individual treatment technologies and in-plant
technologies.
END-OF-PIPE TREATMENT TECHNOLOGIES
This subsection describes individual recovery and treatment
technologies which are used or are suitable for use in treating
wastewater discharges from metal molding and casting facilities.
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 herein include technologies presently demonstrated
within the metal molding and casting category and technologies
demonstrated in the treatment of similar wastewaters in other
industries.
Metal molding and casting wastewater streams characteristically
contain significant levels of toxic organic and inorganic
pollutants. Table VI-3 presented a list of the toxic pollutants
found in metal molding and casting process wastewater streams in
substantial concentrations. These toxic pollutants constitute
the most significant wastewater pollutants in this category. In
general, these pollutants are removed by chemical precipitation
and sedimentation or filtration. Toxic metals may be effectively
removed by precipitation of metal hydroxides or carbonates
utilizing the reaction with lime' sPdium hydroxide, or sodium
carbonate. Oil and grease are" removed by chemical emulsion
breaking and skimming. The sampled plants (12040 and 17089)
analytical data also demonstrate a concurrent removal of toxic
The removal of oil and grease causes a subsequent removal of some
toxic organic pollutants.
The discussion of end-of-pipe treatment technologies is divided
into three parts: the major technologies; the effectiveness of
the major technologies; and minor end-of-pipe technologies.
" 441
-------
MAJOR TECHNOLOGIES
In Sections IX, X, XII, and XIII, the rationale for selecting
treatment systems is discussed. The individual technologies used
in the system are described here. The major end-of-pipe
technologies are: emulsion breaking, oil skimming, oxidation by
potassium permanganate, chemical precipitation of dissolved
metals, sedimentation of suspended solids, and filtration. 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 precipitation operation and are removed with the
precipitated metals in the settling operations. Settling
operations can be evaluated independently of hydroxide or other
chemical precipitation operations, but hydroxide and other
chemical precipitation operations can only be evaluated in
combination with a solids removal operation.
1. Emulsion Breaking
Emulsion breaking is the process of separating an emulsified oil
and water mixture. Emulsified oils are used as coolants,
lubricants, and antioxidants in many metal molding and casting
operations. Discussions of the two methods of emulsion breaking,
chemical and thermal, follow.
Chemical emulsion breaking can be accomplished as a batch process .
or as a continuous process. In the batch process, the mixture of
emulsified oil and water is collected in large tanks equipped
with agitators and a skimmer or some method of decanting.
Decanting can be accomplished with a series of taps positioned
pipes at various levels. Using the taps sequentially, the
separated material is drawn off of the surface of the tank
contents. As an alternate method, water can be drawn off near
the bottom of the tank until oil appears in the wastewater line.
At this point, the oil is diverted to storage tanks for
reprocessing or hauling by a licensed contractor. In the
continuous process, a skimmer, skimming through, or similar
surface material removal device can be used to remove the
material broken out of emulsion. The treated effluent would then
be discharged from the separation tank.
The chemical emulsion breaking process involves several steps.
First, the pH of the solution is lowered to an acidic state
(typically a pH of 3 to 4). The second step involves the
addition of an iron or aluminum salt (e.g., ferrous sulfate).
ferric chloride, or aluminum sulfate. These salts are used to
break the emulsion and free the oils from the water. In
conjunction with the addition of these salts, the mixture is
442
-------
agitated to insure complete contact of the waste water/oil
mixture with the de-emulsifying agent. With the addition of the
proper amount of metallic salts and thorough agitation, emulsions
of 5 percent to 10 percent oil can be reduced to approximately
0.01 percent remaining emulsified oil. In the third step of the
emulsion breaking process, sufficient time is allowed for the
oil/water mixture to separate. Differences in specific gravity
will permit the oil to rise to the surface in approximately 2 to
8 hours. After separation,, the normal procedure involves
skimming or decanting the oil from the top of the tank. Heat, in
the form of steam, can be added to decrease the separation time.
The fourth and final step involves the addition of a chemical
which desalts by precipitating metals from metals from the
remaining, wastewater solution. Calcium chloride or lime are
normally used as the desalting agents and will precipitate out
the metallic ions in the wastewater.
Thermal emulsion breaking can also be operated as a continuous or
batch process. In most cases, however, these systems are
operated intermittently, due to the batch dump nature of most
emulsified oil systems. The emulsified raw waste is collected in
a holding tank until sufficient volume has accumulated to warrant
operating the Thermal Emulsion Breaker (TEB),. The TEB most
commonly used is an evaporation-distillation-decantation
apparatus which separates the spent emulsion into distilled
water, oils and other floating particles, and sludge. Initially,
the raw waste flows from the holding tank into the main
conveyorized chamber. Warm dry air is passed over a large
revolving drum which is partially submerged in the emulsion.
Water evaporates from the surface of the drum and is carried
upward through a filter and a condensing unit. The condensed
water is discharged and can be reused as process makeup, while
the air is reheated and returned to the evaporation stage. As
the concentration of water in the main conveyorized chamber
decreases, oil concentration increases and some gravity
separation occurs. The oils and other emulsified wastes which
separate flow over a weir into a decanting chamber. A rotating
drum skimmer picks up oil from the surface of this chamber and
discharges it for possible reprocessing or contractor removal.
Meanwhile, oily water is drawn from the bottom of the decanting
chamber, reheated, and sent back into the main conveyorized
chamber. This aids in increasing the concentration of oil in the
main chamber and the amount of oil which floats to the top.
Solids which settle out in the main chamber are removed by a
conveyor mechanism, called a flight scraper, which moves slowly
so as not to disturb the settling action.
Application arid Performance - Emulsion breaking technology can be
applied to the treatment of emulsified solutions in the metal
443
-------
molding and casting industry wherever it is necessary to separate
oils, fats, soaps, etc. from aqueous solutions.
The performance attainable by a chemical emulsion breaking
process is dependent on the addition of the proper amount of de-
emulsifying agent, proper agitation and sufficient time for
complete separation. For this reason, the effectiveness of
chemical emulsion breaking systems is somewhat dependent upon the
degree of variability in the raw waste. Since there are several
types of emulsified oils, a detailed study should be conducted to
determine the most effective treatment techniques and chemicals
for a particular application. Emulsified oil concentrations of
50,000 to 100,000 mg/1 can be reduced to approximately 100 ppm
with proper treatment and adequate rise time.
The performance level of a thermal emulsion breaker is dependent
primarily on the characteristics of the raw waste and proper
maintenance and functioning of the TEB components. Some
emulsions may contain volatile compounds which could escape with
the treated effluent. In systems where the water is recycled
back to the process, however, this problem is essentially
eliminated. Experience in at least two copper forming plants has
shown that trace organics or other contaminants found in the TEB
effluent will not adversely affect the lubricants when this water
is recycled back to process emulsions. In one copper forming
plant, typical oil and grease levels were 2872 mg/1 in the raw
waste and 1 mg/1 in the effluent.
Samples were taken before and after chemical emulsion breaking
operations at a metal molding and casting operation (12040) and
at several metal finishing plants. The raw wastewaters from the
metal finishing plants have characteristics (i.e., the oil
concentrations and the organic constituents of the emulsions)
similar to the emulsified oil wastewaters found in the metal
molding and casting industrial category. The analytical results
of this sampling are presented in Table VII-1.
444
-------
TABLE VI1-1
EMULSION BREAKING PERFORMANCE' DATA (mq/1)
Pollutant f
Oil &
Grease
TOC
TSS
Pollutant
Oil & Grease
TOC
TSS
Day 1
In- Ef-
luent fluent
1881 30
1530 54 1
1204 23
Plant 1058
Influent
3320
" 31030
137
Day 1
In- Ef-
Pollutant fluent fluent
Oil & 1
Grease
TOC
TSS
2500 27
128- 950
2000 153
Plant
Day
In-
fluent
7627
2000
7918
12040
2 Day
Ef- In-
fluent fluent
29 7480
, 49 9280
28 6328
Plant 30
Effluent influent
42
262
12
Plant
Day
In-
fluent
2300
2950
1650
210
210
520
12095
2 Day
Ef- In-
fluent fluent
52 12800
1790 1140
187 3470
Plant 38040
Day 1
Pollutant
Oil & Grease
TOC
TSS
Influent
192.8
143
74
Effluent Influent
10 . 6
139
37
210
132
440
3
Ef-
fluent
28
47
20
165
Effluent
24
65
6
3
Ef-
fluent
18
881
63
Day 2
Effluent
129
116
13
445
-------
Plant 40836
Pollutant
Oil & Grease
TOC
TSS
Influent
6060
9360
2612.0
Effluent
98
850
46.0
NOTE: TOC - Total Organic Carbon
TSS - Total Suspended Solids
Summarizing the data presented in the above table, the average
and median oil and grease removal rates are 92.2% and 98.4%,
respectively. The average and median oil and grease effluent
levels are 44.3 mg/1 and 29 mg/1, respectively. Additionally,
the average and median TOC removal rates are 59.8% and 69.0%,
respectively. The average and median TOC effluent levels are 473
mg/1 and 139 mg/1, respectively.
As indicated by the TOC removals noted in Table VII-1 (above),
chemical emulsion breaking can achieve toxic organic pollutant
removal. Chemical emulsion breaking is routinely provided in
aluminum subcategory die casting operations. Table VI1-2
presents toxic organic pollutant analytical data for the two
sampled foundry operations (12040 and 17089) which provide
chemical emulsion breaking. Both of these plants have aluminum
die casting operations. The pollutants listed in Table VII-2 are
those which are considered for regulation in the aluminum die
casting process segment.
TABLE VII-2
EMULSION BREAKING PERFORMANCE DATA (mg/1)
TOXIC ORGANIC POLLUTANTS
Pollutant
001 Acenaphthene
021 2,4,6-trichloro-
phenol
022 Parachlorometa-
cresol
023 Chloroform
039 Fluoranthene
Day
Influent
3,
ND
0.
0.
2.
700
360
410
200
I
Effluent
<0
0
0
0
<0
.010
.012
.250
.044
.010
Plant 1
2040
Day
Influent
ND
ND
0.
<0.
0.
150
010
01 1
2
Effluent
ND
ND
0.
0.
ND
056
073
446
-------
063 N-nitrosocli-n-
propylamirie ND ND
065 Phenol .. ND <0.010
067 Butyl benzyl
phthalate 0.760 ND
072 Benzo(.a)anthracene 0.072 <0. 010
076 Chrysene 0.050 0.015
084 Pyrene ND <0.010
085 Tetrachloro-
ethylene • 0.090 0.071
Phenols (4AAP) 0.288 0.182
ND
<0.010
ND
ND
0.030
0.062
0.270
0.102
ND
0.029
ND
0.018
ND
ND
0.150
0.055
Plant 12040
Day 3
Pollutant
001 Acenaphthene
021 2,4,6-trichloro-
phenol
022 Parachlororneta-
cresol
023 Chloroform
039 Fluoranthene
063 N-nitrosodi-n-
propylamine
065 Phenol
067 Butyl benzyl
phthalate
072 Benzo(a)anthra-
cene
076 Chrysene
084 Pyrene
085 Tetrachloro-
ethylene
Phenols (4AAP)
Influent Effluent
ND
0.044
0.096
<0.010
0.022
ND
<0.010
ND
0.030
ND
0.048
0.350
0.156
<0.010
ND
0.041
0.050
<0.010
ND
<0.010
0.027
0.032
0.01 1
ND
0.058
0.1 02
Pollutant
001 Acenaphthene
021 2,4,6-trichloro-
phenol
022 Parachlorometa-
cresol
Plant 1
Day
Influent
(Melting Fee.
Scrubber)
ND
ro-
0.120
9*~*
ND
7089
1
Influent
(Die
Casting
ND
ND
ND
Effluent
0.114
0.260
ND
447
-------
023 Chloroform
039 Fluoranthene
063 N-nitrosodi-n-
propylamine
065 Phenol
067 Butyl benzyl
phthalate
072 Benzo(a)anthracene ND
076 Chrysene
084 Pyrene
085 Tetrachloro-
ethylene
Phenols (4AAP)
Pollutant
001
021
022
023
039
063
065
067
072
076
084
085
Phenols
Pollutant
001
021
022
023
039
063
065
067
072
0.072
0.023
ND
0.01 1
<0.010
>ne ND
ND
0.029
ND
1 .07
0.460
ND
ND
ND
ND
*
*
<0.010 ;
<0.010
5.430
i
Plant 17089
0.099
ND
ND
0.027
1 .264
ND
ND
ND
0.046
0.525
Day 2
Influent
(Melting Fee
Scrubber)
ND
0.062
ND
0.098
0.014
ND
<0.010
ND
<0.010
<0.010
ND
ND
1 .28
Influent
. (Die i
Casting)
ND
ND
ND
0.460
ND
ND
ND
ND
*
*
<0.010
<0.010
0.278
Plant 17089
Effluent
<0.010
<0.010
ND
0.320
<0.010
ND
0.011
<0.010
ND
ND
<0.010
<0.010
0.259
Day 3
Influent
(Melting Fee
Scrubber)
<0.010
0.235
ND
.0.054
ND
ND
ND
ND
ND
Influent
. (Die
Casting)
ND
2.000
ND
0.340
<0.010
ND
5.000
ND
*
Effluent
<0.010
0.105
ND •
0.24
<0.010
ND
0.013
ND
<0.010
448
-------
076
084
085
Phenols
ND
ND
ND
0.169
0.021
xOv'OlO
4.040-
ND
<0.010
<0.010
0.18
ND:
Not Quantifiable
Not Detected
The following summarizes the
above operations.
effluent levels achieved by the
Pollutant
Effluent Levels (mq/1)
001 Acenaphthene
021 2,4,6-trichlorophenol
022 Parachlorometacresol
023 Chloroform
039 Fluoranthene
063 N-nitrosodi--n-propylamine
065 Phenol
067 Butyl benzyl phthalate
072 Benzo(a)anthracene
076 Chrysene
084 Pyrene
085 Tetrachloroethylene
Phenols (4AAA)
Average
0.019
0.063
0.058
0.138
0.000"
0.000
0.013
0.214
0.008
0.004
0.000
0.054
0.222
Median
d.ooo
0.006
0.020
0.086
0.000
0.000
0.012
0.000
0.000
0.000
0.000
0.052
0.181
Advantages and Limitations. The main advantage of the chemical
emulsion breaking process is the high percentage of oil removal
possible with this system. For proper and economical application
of this process, the oily wastes (oil/water mixture) should be
segregated from other wastewaters either by storage in a holding
tank prior to treatment or by direct inlet to the oil waste
removal system from major collection points. Further, if
significant quantities of free oils are present, it is
advantageous to precede emulsion breaking with gravity
sedimentation. Chemical and energy costs can be high, especially
if heat is used to accelerate the process.
Advantages of the TEB include an extremely high percentage of oil
removal (at least 99 percent in most cases), the separation of
floating oil from settleable sludge, and the production of good
quality water which is available for process reuse. In addition,
no chemical additives are required and the operation is fully
449
-------
automatic, factors which reduce operating costs and maintenance
requirements. Disadvantages of this system are few: the cost of
heat to run the small boiler [about $80 a month for natural gas
for an 1140 liter/day (300 gallon per day) unit], and the
necessary installation of a large storage tank. Some settling
may occur in the holding tank, resulting in a more concentrated
raw waste load during the first day or two of operation. This
higher concentration may result in slightly higher effluent
contamination for the day(s) involved. TEB models are currently
available to handle loads of 150, 300 and 600 gallons per day.
Operational Factors. Reliability: Chemical emulsion breaking can
be highly reliable assuming adequate analysis in the selection of
chemicals and proper operator training to ensure that the
established procedures are followed.
Thermal emulsion breaking is also a very reliable process for the
treatment of emulsified wastes.
Maintainability: For chemical emulsion breaking, routine
maintenance is required on pumps, motors, and valves as well as
periodic cleaning of the treatment tank to remove any sediment
which may accumulate in the tank. The use of acid or acidic
conditions will require a lined or coated tank, and the lining or
coating should be checked periodically.
A TEB unit requires minimal routine maintenance of the TEB
components, and periodic disposal of sludge and oil.
Solid Waste Aspects; Both methods of emulsion breaking generate
sludge oils which must receive proper disposal.
Demonstration Status; Emulsion breaking is a common treatment
technique used by a number of plants, particularly in the
aluminum casting subcategory, in the Metal Molding and Casting
Industry. It is a proven method of effectively treating
emulsified wastes.
2. Oxidation by Potassium Permanganate
Potassium permanganate (KMnO*) is a powerful oxidizing chemical
used to destroy phenolic compounds. It is fed in dry form, and
is not corrosive. It keeps indefinitely when stored in a cool,
dry, and dark environment. Although it presents no health hazard
in its handling, there is some .fire hazard which can be
controlled with the addition of water.
450
-------
Application arid Performance
Potassium permanganate cleaves the aromatic ring structure of
phenol to produce a straight chain aliphatic molecule. The
aliphatic is then further oxidized to C02 and water. Under
actual test conditions on a foundry wastewater, with a flow of 2.5
million liters/day (6.6 MGD), having an initial phenol
concentration of 0.123 mg/1, potassium permanganate was added^ at
concentrations of• 1, 5 and 10 mg/1. After a contact time of 20
minutes, the waste was analyzed for residual phenols. Effluent
concentrations of <0.010 mg/1 were observed. A dosage of l0 mg/1
or a ratio of 80si permanganate to phenol was required to remove
the phenol.
A retention time from one to three hours is sufficient to insure
complete oxidation of the phenol. The initial reaction takes
place almost immediately, and almost 90 percent of the phenol is
oxidized in the first ten minutes. The higher the pH, up to a
value of about 9.5, the shorter the reaction time.
Advantages and Limitations
During the oxidation process, an insoluble compound of manganese
dioxide (Mn02) is formed. This inert product exhibits certain
sorptive properties, which often render it beneficial to the
coagulation and sedimentation of low turbidity, waters.
Operational Factors
Reliability; High, assuming proper feed.
Maintainability; Maintenance of chemical feed equipment and
mixing is required.
Solid Waste Aspects t The increased solid waste volume is
negligible.
Demonstration Status
The use of potassium permanganate to oxidize phenolic compounds
has been demonstrated in foundries, refineries, and other
industrial wastewater treatment operations.
3. 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.
451
-------
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 and fluorides as calcium
fluoride.
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 insoluble
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 small amount of metal will remain dissolved in the
wastewater after complete precipitation. 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 (arid 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 precipitation process and reduce the fraction of a
specific metal in the precipitate.
Application and Performance. Chemical precipitation is used in
the metal molding and : casting industry for precipitation of
dissolved metals. It can be used to remove metal ions such as
aluminum, antimony, arsenic, beryllium, cadmium, chromium,
cobalt, copper,, iron, lead, manganese, mercury, molybdenum, tin
and zinc. The process is also applicable to any substance that
can be transformed into an insoluble form such as fluorides,
452
-------
phosphates, soaps, sulfides and others.
effective, chemical precipitation is
industrial waste treatment.
Because it is simple and
extensively used for
The performance of chemical precipitation depends on several
variables. The most important factors affecting precipitation
effectiveness are:
1 .
2.
3.
4;
Maintenance of an alkaline pH throughout the
precipitation reaction and subsequent settling;
Addition of a sufficient excess of treatment ions to
drive the precipitation reaction to completion;
Addition of an adequate supply of sacrifical ions (suchL
as iron or aluminum) to ensure precipitation and
removal,of specific target ions; and
Effective removal ,. of precipitated solids (see
appropriate technologies discussed under "Solids
Removal").
Control of pH. Regardless 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
and by plotting effluent zinc concentrations against pH as shown
in Figure VII-2-. 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 VI1-3. Flow through this system is
approximately 49,263 1/h (13,000 gal/hr)..
453
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TABLE VII-3
pH CONTROL EFFECT ON METALS
In
Day 1
Out
In
Day 2
REMOVAL
Out
In
Day 3
Out
pH Range 2.4-3.4
(mg/1)
8.5-8.7 1.0-3.0 5.0-6.0 2.0-5.0 6.5-8.1
TSS
Copper
Zinc
39
312
250
0.22
0.31
16
120
19
5.12
32.5 25.0
16
107
43.8
0.66
0.66
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 ort 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 and intermediate values were were achieved
on the third day when pH values were less than desirable but in
between the first and second days.
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 throqgh the system is approximately
22,700 1/hr (6,000 gal/hr).
TABLE VI1-4
EFFECTIVENESS OF SODIUM HYDROXIDE FOR METALS REMOVAL
pH Range
(mg/1)
Cr
Cu
Fe
Day
In
2.1-2.9
0.097
0.063
9.24
1
Out
9.0-9.3
0.0
0.018
0.76
Day
In
2.0-2.4
0.057
0.078
15.5
2
Out
i
8 . 7-9 . 1
0.005
0.014
0.92
Day
In
2.0-2.4
0.068
0.053
9.41
3
Out
8.6-9.1
0.005
0.019
0.95
454
-------
Pb
Mn
Ni
Zn
TSS
1.0
0.11
0.077
.054
0.11
0.06
0.011
0.0
13
1 .36
0 .1 2
0.036
0.12
0.13
0.044
0.009
0.0
1 1
1 .45
0.11
0.069
0.19
0.11
0.044
0.01 1
0^037
11
These data indicate that the system was operated efficiently.
Effluent pH was controlled within the range of 8.6-9.3, and,
while raw waste loadings were not unusually high, most toxic
metals were removed to very low concentrations.
Lime and sodium hydroxide 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-5 shows sampling
data from this system, which uses lime and sodium hydroxide for
pH adjustment, 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 5,000 gal/hr.
455
-------
TABLE VII-5
EFFECTIVENESS OF LIME AND SODIUM HYDROXIDE FOR METALS REMOVAL
pH Range
(mg/1)
Al
Co
Cu
Fe
Mn
Ni
Se
Ti
Zn
TSS
Day
In
9.2-9.6
37.3
3.92
0.65
137
175
6.86
28.6
143
18.5
4390
1
Out
8.3-9.8
0.35
0.0
0.003
0.49
0.12
0.0
0.0
0.0
0.027
9
Day
In
9.2
38.1
4.65
0.63
110
205
5.84
30.2
125
16.2
3595
2
Out
7.6-8.1
0.35
0.0
0.003
0.57
0.012
o.o
o.p
o.b
i
0.044
13
Day
In
9.6
29.9
4.37
0.72
208
245
5.63
27.4
115
17.0
2805
3
Out.
7.8-8.2
0.35
0.0
0.003
0.58
0. 12
0.0
0.0
0.0
0.01
13
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-6 (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-7.
456
-------
TABLE VI 1-6
THEORETICAL SOLUBILITIES OF HYDROXIDES AND SULFIDES
OF SELECTED METALS IN PURE WATER
Metal
Cadmium (Cd++)
Chromium (Cr+++;
Cobalt (Co++)
Copper (Cu++)
Iron (Fe++)
Lead (Pb++)'
Manganese (Mn++!
Mercury (Hg++)
Nickel (Ni++)
Silver (Ag+) .
Tin (Sn++)
Zinc (Zn++)-
As Hydroxide
2.
8
2.
2.
8.
2.
1 .
3 .
6.
13.
1 .
""1"".
3
.4
2
2
9
1
2
9
9
3
1
1
x
x
X
X
X
X
X
X
1
o-
5
10-*
1
1
1
1
1
1
o-
o-
o-
o-
o-
o-
-1
2
i
4
3
4
Solubility of Metal Ion, mg/1
As Carbonate As Sulfide
1.0 x .10-*
7.0 x TO-3
3,9 x ID-2
1.9 x 10-1
2.1 x 10-1
7.0 x 10-*.
6.7 x 10-10
No precipitate
1 .
5.
3.
3.
2.
9.
6.
7.
3.
2.
0
8
4
8
1
0
9
4
8
3
x
x
X
X
X
X
X
X
X
X
1
1
1
1
1
1
1
1
1
1
0-8
o-.» °
0-5
0-9
o-3
Q-20
0-8
Q-12
0-8
o-7
TABLE VI1-7
SAMPLING DATA FROM SULFIDE
PRECIPITATION-SEDIMENTATION SYSTEMS
Lime, FeS, Poly-
electrolyte,
Treatment Settle, Filter
PH
(mg/1)
Cr+6
Cr
Cu
Fe
Ni
Zn
In
Out
5.0-6.8
25.6
32.3
0.52
39.5
8-9
-------
Summary Report, Control and Treatment Technology for the
Metal Finishing Industry; Sulfide Precipitation, USEPA, EPA
No. 625/8/80-003, 1979.
Industrial Finishing, Vol. 35, No. 11, November, 1979.
Electroplating sampling data from plant 27045.
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 or better
than that for the heavy 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 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.
I
Based on the available data, Table VJII-8 shows the minimum
reliably attainable effluent concentrations for sulfide
precipitation-sedimentation systems. Th0se values are used to
calculate performance predictions of sulfide precipitation-
sedimentation systems.
458
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-TABLE VI1-8
SULFIDE PREC IP I TAT ION-SEP IMENT AT I ON'. PERFORMANCE
Parameter
Cd
CrT
Cu
Pb
-Hg
Ni .
AQ
Zn
Treated Effluent
(mg/1)
0.01
0.05
0.05
0.01
0.03
P.vP.5
0.05
0.01
Table VII-8 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. , - ....'.--.•
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 ("Heavy Metals
Removal," by Kenneth Lanovette, Chemical Engineerinq/Deskbook
Issue, Oct. 17, 1977) explain this phenomenon.
Coprecipitation With Iron- The presence of substantial quantites
of iron in wastewaters contaminated with toxic metals before
treatment has been shown to improve the removal of these toxic
metals. In some cases this iron is an integral part of the
process wastewater; in other cases iron is deliberately added as
a preliminary; or first step of treatment. The iron functions to
459 .
-------
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.
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 VI1-9.
Table VII-9
FERRITE CO-PRECIPITATION PERFORMANCE
Metal
Mercury
Cadmium
Copper
Zinc
Chromium
Manganese
Nickel
Iron
Bismuth
Lead
Influent(mg/1)
7.4
240
10
18
10
12
1,000
600
240
475
Effluent(mg/1)
0.001
0.008
0.010
0.016
<0.010
0.007
0.200
0.06
0. 100
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.
Advantages and Limitations
Chemical precipitation has proven to be
for removing many pollutants from industrial
460
an effective technique
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 of mixed wastewaters and treatment
chemicals, or because of the potentially hazardous situation
involved with the storage and handling of those chemicals. 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,
hydroxide precipitation usually makes recovery of the
precipitated metals difficult, because of the heterogeneous
nature of most hydroxide 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 prevent 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 post 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 (Na^SC^). The cost of
sulfide precipitants is high in comparison with 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 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 su.lfide
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
461 .
-------
changes in raw waste and reducing the amount of
precipitant required.
Operational
Factors.
Reliability:
Alkaline
sulfide
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. Full scale commercial sulfide
precipitation units are in operation at numerous industrial
wastewater treatment systems. As noted earlier, sedimentation to
remove precipitates is discussed separately.
Use in the Metal
precipitation
Molding and Casting Category. Chemical
is used widely in each subcategory of the metal
molding and casting industry. The quality of treatment provided,
however, is variable. As a result, treatment performance at
metals casting industry plants nominally practicing the same
wastewater treatment procedures can vary widely.
4,
Granular Bed Filtration
Filtration occurs in nature as groundwaters are cleansed by
passage through the soil. 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 methbd of pressurization.
Traditional rate classifications are slow sand, rapid sand, and
high rate mixed media. In the slow sand filter, flux or
462
-------
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
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 VI1-4 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
permitsgravity 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.
463
-------
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. i
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 filtered 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.
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 as follows:
i
Slow Sand
Rapid Sand
High Rate Mixed Media
2.04 -,5.30 1/sq m-hr
40.74 - 51.48 1/sq m-hr
81.48 - 122.22 1/sq m-hr
Suspended solids are commonly removed frojn 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) iare adsorbed on the
464
-------
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 concentrations to less than 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-10 below. = ,
Table VII-10 ,
Plant ID ft
06097
13924 ,
18538
30172
36048
mean
MULTIMEDIA'FILTER PERFORMANCE
TSS Effluent Concentration, mq/1
0.
1 .
2.
1 .
1 .
2.
2.
o,
8,
8,
0
4,
1 ,
61
0.
2.
3.
7.
2.
o>
2f
o,
6,
0.
5.
2.
1 .
1 .
5 :
6, 4.0, 4.0, 3.0, 2.:
0, 5.6, 3.6, 2.4, 3.^
0
5 ' ' " ' ' '
2,
4
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
filtertechnology 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.
465
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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
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 a
number of foundry operations, particularly in the lead casting
subcategory. Their use in polishing industrial clarifier
effluent is increasing, and the technology is proven and
conventional. Granular bed filtration is used in many
manufacturing plants. However, little data is available to
characterize the effectiveness of filters presently in use within
this industry.
5. Pressure Filtration
Pressure
material
pressure
provides
force.
pressure
filtration works by pumping the liquid through a filter
which is impenetrable to the solid phase. The positive
exerted by the feed pumps or other mechanical means
the pressure differential which is the principal driving
Figure VI1-5 represents the operation of one type of
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 is mounted a filter
made of cloth or a synthetic fiber. 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.
466
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Application arid Performance. Pressure filtration is used in coil
coating 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. . , ih.
In a typical pressure filter, chemically preconditioned sludge
detained in the unit for one to three hours under pressures
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. ' J ;
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
467
-------
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 metal
molding and casting wastewaters necessitates proper disposal.
Demonstration Status. Pressure filtration is a commonly used
technology in a great many commercial applications.
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-6 shows two
typical settling devices.
Settling is often preceded by chemical precipitation, which
converts dissolved pollutants to a 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,
the addition of settling aids such as alum or polymeric
flocculants is often economically attractive.
i
In practice, chemical precipitation often precedes settling, and
inorganic coagulants or polyelectrolytic fJocculants 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.
i
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
460
-------
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.
Application and Performance. Settling and clarification are used
in the coil coating category to remove precipitated metals.
Settling can bev 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 (casting), metal
finishing, and metal working. In addition to toxic metals, the
suitably precipitated materials effectively removed by settling
include aluminum, iron, manganese, and fluoride.
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 time, 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
simple settling is a function of the retention time, particle
size and density, and the surface area of the basin.
The data displayed in Table VII-11 indicate suspended solids
removal efficiencies in settling systems..
469
-------
TABLE VII-1]
PERFORMANCE OF SELECTED SETTLING SYSTEMS
SETTLING
DEVICE
Lagoon
Clarif ier
Clarif ier
Settling
Pond
Settling
Tank
Clarif ier
Lagoon
Clarif ier
Clarif ier
Settling
Tank
In
54
1100
451
284
170
& -
4390
182
295
SUSPENDED
Day 1
Out
6
9
17
6
1
-
9
13
10
SOLIpS CONCENTRATION
In
5J5
1900
— .
242
50
1662
3595
118
42
Day 2
Out
6
12
_
10
1
16
12
14
10
In
50
1620
_
520
_
1298
2805
174
153
(mg/1)
Day 3
Out
5
5
14
«
4
13
23
8
PLANT ID
01057
09025
11058
12075
19019
33617
40063
44062
46050
The mean effluent TSS concentration obtained by the plants shown
in Table VII-11 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 a.chieve 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.
470
-------
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 by storm water runoff, but proper system
design will prevent this.
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.
Demonstrat ion 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. Sedimentation or clarification is used
in the majority of foundry operations.
Settling is used both as .part of end-of-pipe treatment and .within
the process (I.e., air pollution control devices and casting
quench).
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 r«;use. The water portion is allowed to flow under
the rotating drum. Occasionally, an underflow baffle is
471
-------
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 increasing oil removal efficiency.
i
Application and Performance. Oil cleaned from the strip is a
principal source of oil. 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
often used in conjunction with air flotation or clarification in
order to increase its effectiveness.
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 below illustrate the capabil
with both extremely high and moderate oil
472
ities of the technology
influent levels.
-------
Table VI1-12
SKIMMING PERFORMANCE
Oil & Grease
mg/1
Plant Skimmer Type
06058 API
06058 Belt
In
224,669
19.4
Out
17.9
8.3
This data is intended to be illustrative of the very high level
of oil and grease removals attainable in a simple two stage oil
removal system. Based on the performance of installations in a
variety of manufacturing plants and permit requirements that are
constantly 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 due to 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 fifteen polynuclear aromatic
hydrocarbon (PAH) compounds in octanol and water are listed
below.
473
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PAH
Priority Pollutant
Log Octanol/Water
Partition Coefficient
001 Acenaphthene
039 Fluoranthene
072 Benzo(a)anthracene
073 Benzo(a)pyrene
074 3,4-benzofluoranthene
075 Benzo(k)fluoranthene
076 Chrysene
077 Acenaphthylene
078 Anthracene
079 Benzo(ghi)perylene
080 Fluorene
081 Phenanthrene
082 Dibenzo(a,h)anthracene
083 Indeno(l,2,3,cd)pyrene
084 Pyrene
4.33
33
£l
04
5,
5,
6,
6.57
6.84
5.61
4.p7
15
>3
4.18
4.46
,97
66
4.4!
7.2;
5,
7,
5.32
A study of priority organic compounds commonly found in metal
forming operations 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 these 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 organic compounds present in the raw
waste. The API oil-water separation system and the thermal
emulsion breaker (TEB) performed notably in this regard, as shown
in the following table (all values in mg/1).
474
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TABLE VII-13
TRACE ORGANIC .REMOVAL B>T 'SKIMMING
API PLUS BELT SKIMMERS
(From Plant 06058)
Concentrat ion (mg/1)
Inf. Eff..
Oil & Grease
Chloroform
Methylene Chloride
Naphthalene
N-nitrosodiphenylamine
Bis-2-ethylhexylphthalate
Diethyl phthalate
Butylbenzylphthalate
Di-n-octyl phthalate
Anthracene - phenanthrene
Toluene
225,000
0.023
0..013
2.31
59.0
11.0
0.005
0.019
16.4
0.02
14.6
0.007
0.012
0.004
0. 182
0.027
0.002.
0.002.
0.014
0.012
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
are removed, also. _
Percent Removal
Oil & Grease
Organics
Plant-Day
1054-3
13029-2
13029-3
38053-1
38053-2
Mean
The unit operation most applicable to removal of trace priority
organics is adsorption, while chemical emulsion breaking and
chemical oxidation are other possibilities. Biological
degradation is not generally applicable because the organics are
475
-------
not present in sufficient concentration j;o 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
being removed by air flotation or other more sophisticated
technologies.
Operational Factors. Reliability: Because
skimming is a very reliable technique.
of its simplicity,
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.
i
Demonstration Status. Skimming is a common operation utilized
extensively by industrial waste treatment systems. Oil skimming
is used in foundry operations.
MAJOR TECHNOLOGY EFFECTIVENESS
i
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 oil skimming is
installed and operating properly where appropriate.
L&S Performance — Combined Metals Data Base
Before proposal, chemical analysis data were collected of raw
waste (treatment influent) and treated waste (treatment effluent)
from 55 plants (126 data days) sampled by EPA (or its contractor)
476
-------
using EPA sampling and chemical analysis protocols. These data
are the data base for determining the effectiveness of L&S
technology. Each of these pla'nts belongs to at least one of the
following industry categories: aluminum forming, battery
manufacturing, coil coating, copper forming, electroplating and
porcelain enameling. All of the plants employ pH adjustment and
hydroxide precipitation using lime or caustic, followed by
settling (tank, lagoon or clarifier) for solids removal. Most
also add a coagulant or flocculant prior to solids removal.
An analysis of this data was presented in the development
documents for the proposed regulations for coil coating and
porcelain enameling (January 1981). In response to the proposal,
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.
The main conclusion drawn from the analysis of variance is that,
with the exception of electroplating, the categories 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. Cases that appeared to be
marginally different were not unexpected (such as copper in
copper forming and lead in lead battery manufacturing) were
accommodated in developing limitations by using the larger values
obtained from the marginally different category to characterize
the entire data set. ' , ' '.
The statistical analysis provides support for the technical
engineering judgment that electroplating wastewaters are
different from most metal processing wastewaters. These
differences may be further explained by differences in the
constituents and relative amounts of pollutants in the raw
wastewaters. Therefore, the wastewater data derived from plants
that only electroplate are not used in developing limitations for
the coil coating category.
477
-------
After removing the electroplating data, data from 21 plants and
52 days of sampling remained. Eleven of these plants and 25 days
of sampling are from coil coating operations.
For the purpose of developing treatment effectiveness, certain
data were deleted from the data base before examination for
homogeneity. These deletions were made to ensure that the data
reflect properly operated treatment systems and actual pollutant
removal. The following criteria were used in making these
deletions:
o Plants where malfunctioning processes or treatment systems
at time of sampling were identified.
o Data days where pH was less than 7.0 or TSS was greater than
50 mg/1. (This is a prima facie indication of poor
operation).
o Data points where the raw waste valu£ was too low to assure
actual pollutant removal occurred (i.e., less than 0.1 mg/1
of pollutant in raw waste).
t
Collectively, these selection criteria insure that the data are
from properly operating lime and settle treatment facilities.
The remaining data are displayed graphically in Figures VI1-7 to
VII-15. This common or combined metals data base provides a more
sound and usable basis for estimating treatment effectiveness and
statistical variability of lime and settle technology than the
available data from any one category.
One-day Effluent Values
The basis 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
of effluent guidelines categories. In the case of the combined
metal categories data base, there are too few data from any one
plant to verify formally the lognormal assumption. Thus, we
assumed measurements of each pollutant from a particular plant,
denoted by X, followed a lognormal distribution with log mean n
and log variance o2. The mean, variance and 99th percentile of X
are then:
mean of X = E(X) = exp (v + a2 /2)
variance of X = V(X) = exp (2 u + o2) [exp( o2 )-l]
99th percentile = X.99 = exp ( u + 2.33 o)
478
-------
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 u and variance o2. Using the basis
assumption of lognormality 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
plant i where
pollutant at
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
:» Yij/n
i=l j=l
where . n = total number of observations
. • '..-. _ i •
". = Ji
and
V(y) = pooled log variance
':;":' "••-•• I • ' ' ........ "
= (Ji - 1 ) Si2
479
-------
i = 1
I i
(Ji - 1)
i = 1
j
where Si2 = log variance at plant i
Ji ;
s (yij - yi)2/(Ji - 1)
yi = log mean at plant i.
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
i
mean = E(X) = exp(y) n (0.5 V(y)) ;
|
99th percentile = X.99 = exp [y + 2.33 V(y) ]
i
where y (.) 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
accommodate situations in which a category or categories stood
out as being marginally different from the others. 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.
Thus, copper effluent values shown in Table VI1-14 are based only
on the copper effluent data from the 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.
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 VII-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
480
-------
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 approach used for the TO
measurements values was employed previously for the
electroplating category (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). That is, the
distribution of the average of 10 samples from a lognormal was
approximated by another lognormal distribution. Although the
approximation is not 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. 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 1 0-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 1 0 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
xx and o2, 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-)
Vo
Where E(X) and V(x'j are the mean and variance of X, respectively,
defined above. We then assume that X,0 follows a lognormal
distribution with log mean U10 and log standard deviation o10.
The mean and variance of X,0 are then
481
-------
E(X10) = exp ( 10 + 0.5 210) ;
V(X10) - exp (2 10 + o210) [exp( O2lo;)-l]
Now, 10 and o210 can be derived in terms of xx and o2 as
10 = xx + o2 /2 + 0.5 In [l+(exp( o2 -1)/N]
o2 = In [l+(exp( o2 ) -D/N] '.
Therefore, U10 and o210 can be estimated using the above
relationships and the estimates of U and o2 obtained for the
underlying lognormal distribution. The 10 sample limitation
value was determined by the estimate of ' the approximate 99th
percentile of the distribution of the 10 sample average given by
X,0 (.99) - exp ( 10 + 2.33
10
10 /
where 10 and o 10 are the estimates of »10 and a
respectively.
I
30 Sample Average:
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. The monthly
limitations based on 10 consecutive measurements were determined
using the lognormal approximation described above because 10
measurements was, in this case, considered 'too small a number for
use of the Central Limit Theorem.
482
-------
30 Sample Average Calculation
The formulas for the 30sample 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 X,0 = E(X30) = E(X) ••
variance of X30 .« V(X30) = V(X) 30.
The 30 sample average value was determined by the estimate of the
approximate 99th percentlie of the distribution of the 30'sample-
average given by
•X,n(....) = E(X) = 2.33 V(X)/30
where
E(X) = exp(y) n (0.5v(y))
and;V(X),= exp'U'y) [ n(2V(y))
n n-2 V(y))]
n-1
The formulas for E(X) and V(X) are estimates
respectively given in Aitchison, J. and
Loqnormal Distribution, Cambridge University
45.
- Table VII-14
of E(X) and V(X)
J.A.C. Brown, The
Press, 1963, page
COMBINED METALS DATA EFFLUENT VALUES (mq/1)
Cd
Cr
Cu
Pb
Ni
Zn
Fe
Mn
TSS
Mean
0.079
0.08
0.58
0.12
0.57
0.30^
0.41
0.21
12.0
One Day
Max.
0.32
0.42
1 .90
0.15
1 .41
1 .33
1 .23
0.43
41 .0
10 Day Avg,
Max.
0.15
0. 17
1 .00
0.13
1 .00
0.56
0.63
0.34
20.0
30 Day Avg.
Max.
0.13
0.12
0.73
0.12
0.75
0.41 .
0.51
0.27
15.5
483
-------
Application
The Agency received comments, in response to proposed coil
coating and porcelain enameling regulations, 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 author i ty.
Additional Pollutants
A number of other pollutant parameters were considered with
regard to the performance of lime and settle treatment systems in
removing them from industrial wastewater.| Performance data for
these parameters is not readily available, so data available to
the Agency in other categories has been selectively used to
determine the long term average. I
i
i
Performance of lime and settle technology for each pollutant.
These data indicate that the concentrations shown in Table VII-15
are reliably attainable with hydroxide precipitation and
settling. The precipitation of silver appears to be accomplished
by alkaline chloride precipitation and adequate chloride ions
must be available for this reaction to occur.
484
-------
TABLE VII-15
. • L&S PERFORMANCE
ADDITIONAL POLLUTANTS
Pollutant
Sb
As
Be
Hg
Se
Ag
Th
Al
Co
F
Average Performance (mg/1)
; -I
0.7
0.51
0.30
0.06
0.30
•-"-:••-• 0.10
0.50,
1.11
0.05
14.5
In establishing which data were suitable for use in Table VII-15
two factors were heavily weighed; (1) the nature of, the
wastewater; (2) and 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 and VII-17 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. The available
date 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.
485
-------
TABLE VI1-16
COMBINED METALS DATA SET - UNTREATED WASTEWATER
Pollutant
Cd
Cr
Cu
Pb
Ni
Zn
Fe
Mn
TSS
MAXIMUM
i
i
Min. Cone (mg/1)
<0.1
<0.1
<0.1
<0.1
<0.1
<0. 1 .
<0 . 1 |
<0. 1
4.6 ;
TABLE VI I- 17
POLLUTANT LEVEL IN UNTREATED
Max. Cone, (mg/1)
3.83
116
108
29.2
27.5
337.
263
5.98
4390
WASTEWATER
ADDITIONAL POLLUTANT!^
(mg/1)
Pollutant
As
Be
Cd
Cr
Cu
Pb
Ni
Ag
Zn
F
Fe
O&G
TSS
As & Se
4.2
Be
10.24
Ag
0.18
33.2
6.5
3.62
16.9
352
8.60
1 .24
0.35
0.12
646
796
0.2
1 10.5
"1
100
1512*
16
587.8
3 22.8
2.2
5.35
0.69
760
2.8
5.6
486
-------
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.
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 is
comparable with the combined data set matrix.
Aluminum (Al) -The 1.11 mg/1 treatability ofaluminum is based
on the mean performance of one aluminum forming plant and one
coil coating plant. Both of the plants are from categories
considered in the combined metals data set, assuring untreated
wastewater matrix comparability.
Cobalt (Co) - The 0.05 mg/1 treatability is based on nearly
complete~reinoval 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 is based on
the—meanperformance of an electronics and electrical component
manufacturing plant. The untreated wastewater matrix for this
plant shown in Table VII-17 is comparable to the combined metals
data,set.
LS&F Performance
Tables VI1-18 and Vll-l9 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 waste data was collected only occasionally at each facility
and the raw waste 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
487
-------
spurious points and discrepancies. The method of treating the
data base is discussed below under lime, settle, and filter
treatment effectiveness.
Table VII-20 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.
TABLE VII-18
PRECIPITATION-SETTLING-FILTRATION (LS&F) PERFORMANCE
Plant A
Parameters
No Pts.
For 1979-Treated Wastewater
Range mq/1
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
For 1978-Treated Wastewater
Cr
Cu
Ni
Zn
Fe
Raw Waste
Cr
Cu
Ni
Zn
Fe
47
28
47
47
21
5
5
5
5
5
0.01 -
0.005 -
0.10 -
0.08 -
0.26 -
0.07
0.055
0.92
2.35
1 .1
32.0
0.08
1 .65
33.2
10.0
72.0
0.45
20.0
32.0
95.0
Mean +_
std. dev.
0.0:45 +_0.029
0.019 ±0.006
0.22 +_0.13
0.17 +0.09
0.06 +_0. 1 0
0.016 +0.010
0.20 +0.14
0.23 +_0.34
0.49 +0.18
Mean + 2
std. dev,
0. 10
0.03
0.48
0.35
0.26
0.04
0.48
0.91
0.85
488
-------
TABLE VII-19
Parameters
, No Pts .
Plant B
Range mg/1
Mean + Mean + 2
std. dev. std. dev.
For 1 979-freated Wastewater
Cr
Cu
Ni
Zn' , ,
Fe
TSS
175
176
175
V 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
0.068 +0.075
0.024 +0.021
0.219 +0.234
0.054 +0.064
0.303 +0.398
0.22
0.07
0.69
0.18
1 .10
For 1978r-Treated. Wastewater
Cr
Cu
Ni
Zn
Fe
Total 1974-1
Cr
Cu
Ni
Zn
Fe -'.
Raw Waste
Cr
Cu
.Ni
Zn
Fe
TSS
144
143
143
131
'...,144
979-Treated
1288
1290 -.-
1287
1273
1 287
3
3
3
2
3
2
0.0
0.0
0.0
0.0
0.0
- 0.70
- 0.23
- 1 .03
- 0.24
- 1 .76
0.059 +0.088
0.017 +0.020
0.147 +0.142
0.037 +0.034
0.200 +0.223
0.24
0.06
0.43
0.1 1
0.47
Wastewater
0.0
0.0
0.0
0.0
0.0
2.80
0.09
1 .61
2.35
3.13
177
- 0.56
- 0;23
- 1 .88
- 0.66
- 3.15
- 9.15
- 0.27
- 4.89
••- 3.39
-35.9
-466.
0.038+0.055
0.01 1 +0.016
0. 184 +0.21 1
0.035 +0.045
0.402 +_0.509
5.90
0.17
3.33
22.4
0 . 1 5
0.04
0.60
0.13
1 .42
489
-------
TABLE VII-20
PRECIPITATION-SETTLING-FILTRATION (LS&F) PERFORMANCE
Plant C
For Treated Wastewater
Parameters No Pts.
For Treated Wastewater
Range mq/1
Mean +_
std. dev.
Cd
Zn
TSS
pH
103
103
103
103
0.010 - 0.500 0.049 +0.049
0.039 - 0.899 0.290 +.0.131
0.100 - 5.00 1.244 +1.043
7.1 - 7.9 9.2* ~
Mean + 2
std. dev,
0.147
0.552
3.33
For Untreated Wastewater
Cd
Zn
•Fe
TSS
pH
103
103
3
103
103
0.039 - 2.319 0.^42 +0.381 1.304
0.949 -29.8 1.1.009 +6.933 24.956
0.255
5.616 +2.896 11.408
7.6*
0.107 - 0.46
0.80 -19.6
6.8 - 8.2
* pH value is median of 103 values.
These data are presented to demonstrate the performance of
precipitation-settling-filtration (LS&F) technology under actual
operating conditions and over a long periodl of time.
i
i
It should be noted that the iron content of the raw waste of
plants A and B is high while that for Plant C is low. This
results, for plants A and B, in coprecipitation 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
consistant 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
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 non-ferrous smelting and refining is
directly applicable to the aluminum forming, copper forming,
490
-------
battery manufacturing, coil coating, and metal molding and
casting categories, as well as to the porcelain enameling and
nonferrous smelting and refining.
Analysis of 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
metals data base. The mean variability factor for eight
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 average variability factors
are: one day maximum - 4.051; ten day average - 1.899; and 30 day
average - 1.646.) For values not calculated from the .common data
base 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. ,
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 occured 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.
Another approach was also used as a check on the above method of
eliminating certain high values. The, minimum values of raw
wastewater concentrations f.rom Plant B for the same four
pollutants were compared to the total set of values for the.
corresponding pollutants. Any day on which the 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
491
-------
sigma) and logic (treated waste should be less than raw waste)
seem to coincide, the data base with the 51 spurious data days
eliminated is the basis for all further analysis. Range, mean,
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. j
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-18 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 1.02 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 0.31 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
varaiability 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
for that pollutant. Other LS&F values are calculated using the
long term average or mean and the appropriate variability
factors. Mean values for LS&F for pollutants not already
discussed are derived by reducing the L&S mean by one-third. The
one-third reduction was established after examining the percent
reduction in concentrations going from L&S to LS&F data for Cd,
492
-------
Cr, Ni, Zn, and Fe. The average reduction is 0.3338 or one
third. . . ':! . . '. ..... .,, ' ..._... ;..,', . ...... , , „ . .
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 waste.waters* Therefore, the mean
concentration value achieved is not used; LS&F mean used is
derived from the L&S technology.
t ' . "•"'.•' .-.--,
The mean concentration of lead is not reduced from the L&S value
because of the relatively high solubility of lead carbonate.
The filter performance for removing TSS as shown in Table VII-10
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 values of 10 and 15, respectively, which are
used for LS&F. ....-.'..
Although iron was reduced, 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.
493
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TABLE VII-21
SUMMARY OF TREATMENT EFFECTIVENESS
(mg/1)
Pollutant
Parameter
Mean
114 Sb
115 As
1 17 Be
118 Cd
119 Cr
120 Cu
121 CN
122 Pb
123 Hg
124 Ni
125 Se
126 Ag
127 Th
128 Zn
Al
Co
F
Fe
Mn
P
O&G
TSS
0.05
0.51
0.30
0.079
0.080
0.58
0.07
0.12
0.06
0.57
0.01
0.1
0.50
0.30
1.11
0.07
14.2
0.41
0.21
4.08
12.0
L&S
Technology
System
One
Day
Max.
0.21
2.09
1 .23
0.32
0.42
1 .90
0.29
0. 15
0.25
1 .41
0.04
0.41
2.05
1 .33
4.55
0.29
58.2
1 .23
0.43
16.7
20.0
41 .0
Ten
Day
Avq.
0.09
0.86
0.51
0.15
0.17
1 .00
0.12
0.13
0.10
1 .00
0.02
0. 17
0.84
0.56
1 .86
0.12
23.8
0.63
0.34
6.83
12.0
20.0
Thirty
Day
Avg.
0.08
0.83
0.49
0. 13
0. 12
0.73
0.11
0.12
0.10
0.75
0.02
0. 16
0.81
0.41
1 .80
0.1 1
23.0
0.51
0.27
6.60
10.0
15.5
494
-------
Pollutant
Parameter
" LS&F _' " "'_'
Technology
System
One
Day
Mean
1
1
1
1
1
1
1
•1
1
1
1
1
1
1
X"
14
15
17
18
19
20
21
22
23
24
25
26
27
28
Sb
As
Be
Cd,
Cr
Cu
CN
Pb
Hg
Ni
Se
Ag
Th
Zn
Al
Co
F
Fe
Mn
P
O&G
TSS
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
9
0
0
2
2
.034
.34
.20
.049
.07
.39
.047
.08
.036
.22
.007
.07
.34
.23
.74
.05
.46
.28
.14
.72
"" "" '
.6
Max.
0
1
0
" 0
0
1
0
0
0
0
0
0
1
1
3
0
38
1
' o
11
10
15
. 14
.39
.82
.20
.37
.28
.20
.10
.15
.55
.03
.29
.40
.02
.03
.21
.8
.23
.30
.2
. 0
.0
Ten
Day
Av
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
1 .
0.
15.
0.
0.
4.
10.
12.
Thirty
Day
g. Avq.
06
57
34
08
15
61
08
09
06
37
01
12
57
42
24
09
8
63
23
6
0
0
0
0
0
• 0
0
0
0
0
0
0
0
0
0
0
1
0
15
0
0
4
10
10
.06
.55
•32
.08
.10
.49
.08
.08
.06
.29
.01
.10 ,
.55
.31
.20
. 08
.3
•5,1
. 19
.4
.0
.0
. 495
-------
MINOR TECHNOLOGIES
Several other treatment technologies were considered for possible
application in BPT or BAT. These technologies are presented here
with a full discussion for most of them. A few are described
only briefly because of limited technical development.
i
8. Carbon Adsorption
I
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, 500-1500 m2/sq m resulting from a large number 'of
internal pores. Pore sizes generally range from 10-100 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-
preferential ly 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
496
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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-I6. 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.
Application and Performance. Carbon adsorption is used to remove
mercury fronf w,astewaters. The removal rate is influenced by the
mercury level in the influent to the adsorption unit. Removal
levels found at three manufacturing facilities are:
Table VII-22
ACTIVATED CARBON PERFORMANCE (MERCURY)
Mercury levels - mq/1
Plant
A
B
C
In
28.0
0.36
0.008
Out
0.9
0.015
0.0005
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 organises "of particular interest, activated
carbon was very effective in removing 2,4-dimethylphenol,
fluoranthene, isophorone, naphthalene, all phthalates, and
phenanthrene. It was reasonably effective on -1/1/J--
trichloroethane, 1,1-dichloroethane, phenol, and toluene. Table
VI1-23 summarizes the treatability effectiveness for most of the
organic priority pollutants by-''activated -carbon as compiled by
EPA Table VII-24 summarizes classes of organic compounds
together with examples of organics that are readily adsorbed.. on-
carbon.
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
497
-------
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 usage 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 beeri
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 the removing and some
times recovering, of 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 certain 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-17.
498
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There are three common types of centrifuges: the disc, basket,
and conveyor type. All three operate by removing solids under
the influence of centrifugal force. The fundamental difference
between the three types is the method by which solids are
collected in and discharged from the bowl.
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,
they are moved by a screw to the end of the machine, at which
point whey 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 concentratipn. Assuming proper design and
operation, the solids content of the sludge can be increased to
20-35 percent. , : A -
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. ' " '"' ' '" ' ~." ' ""
499
-------
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.
I
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 a!nd 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
•500
-------
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.
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 (e.g., die casting or casting quench) which do not
separate readily in simple gravity systems. The three stage
system described above has achieved effluent concentrations of
10-15 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 arid therefore not subject to frequent regeneration or
replacement requirements. Large loads or inadequate
pretreatment, however, may result in plugging or bypass of
coalescing stages.
501
-------
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 wastewaters.
11. 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 VI1-18 and discussed below.
Atmospheric
the liquid.
sprayed on
surface and
evaporation
evaporation could be accomplished simply by boiling
However, to aid evaporation, heated liquid is
an evaporation surface, and air is blown over the
subsequently released to the atmosphere. Thus,
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
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.1 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
humidif ication 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) ajre removed by a vacuum
pump. Vacuum evaporation may be either single or double effect.
502
-------
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. Another means of increasing
energy efficiency is vapor recompression (thermal or mechanical),
which enables heat to be transferred from the condensing water
vapor to the evaporating wastewater. Vacuum evaporation
equipment may be classified as submerged tube or climbing film
evaporation units.
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
of the condenser cooling water through a venturi. Waste water
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. Waste water
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 se^al provided by the
condensate keeps the vacuum in the system from being broken.
503
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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.
i
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
totally integrated evaporation system. Also, in some cases solar
heating could be inexpensively and effectively applied to
evaporation units.
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 distillabjle impurities in the
process stream are carried over with the, product water and must
be handled by pre or post treatment.
504
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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 handling corrosive liquids.
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
does not generate appreciable quantities of solid waste.
process
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.
No data have been reported showing the use of evaporation in
metal molding and casting industry operations.
.12. 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
principle, this process is the opposite of sedimentation. Figure
VII-19 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.
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
505
-------
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 frpm the intermolecular
attraction exerted at the interface between the solid particle
and gaseous bubble.
Vacuum Flotation - This process consists Of saturating the waste
water 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 thie 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.
Auxilliary equipment includes an aeration tank for saturating the
506
-------
wastewater with air, a tank with a short retention time
removal of large bubbles, vacuum pumps,, and sludge pumps.
for
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 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 relatively 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-liqu,id 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
volume of sludge which must be further treated or properly
disposed.
Demonstration Status. Flotation is a fully developed process,,
which demonstrated in this industry, is readily available for the
treatment of a wide variety of industrial waste streams.
13. Gravity Sludge: Thickening
In the gravity thickening process, dilute sludge is fed from a
primary settling tank or clarifier to a thickening tank where
507
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rakes stir the sludge gently to density it and to push it to a
central collection well. The supernatant is returned to the
primary settling tank. The thickened sludtje that collects on the
bottom of the tank is pumped to dewatering equipment or hauled
away. Figure VII-20 shows the construction of a gravity
thickener.
I
i
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.
I
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).
Maintainability: Approximately 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.
508
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Demonstration Status. Gravity sludge thickeners are used
throughout this industry, to reduce water content to a level where
the sludge may be efficiently handled. Further dewatering is
usually practiced to minimize the costs of hauling the sludge to
approved landfill areas.
14. 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 VII-21 (page 289) 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. -v"-- •-. .
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
509 /
-------
concentrations as high as 15 to 20 percent. The
filtration depends on the drainability of the sludge.
rate of
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.
• i
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.
i
j
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
favorable climactic conditions, proper bed design
avoid excessive or unequal sludge application.
is high with
and care to
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 pr 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 |Ded or landfill should
include provisions for runoff control and leachate monitoring.
510
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Demonstration Status. Sludge beds have been in common use in
both municipal and industrial (including foundries) facilities
for many years. However, protection of ground water from,
contamination is not always adequate.
15. Ultrafiltration
Ultrafiltration (UF) is a process which uses semipermeable
polymeri'c membranes to separate emulsified or colloidal materials
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 10 to 100 psig. 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 VI1-22 represents the Ultrafiltration process.
Application and Performance. Ultrafiltration has potential
application to metals casting industry plants for separation ot
emulsified oils from casting quench, die casting and die lube
waste streams. Over one hundred such units now operate in tne
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
are 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.
TheToTlowl rig test data indicate Ultrafiltration performance
(note that UF is not intended to remove dissolved solids):
" 511
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TABLE VI1-23
TREATABILITY RATING OF PRIORITY POLLUTANTS
UTILIZING CARBON ADSORPTION
Priority Pollutant
001 Acenaphthene
002 Aroclein
003 Acrylonitrile
004 Benzene
005 Bcnzidine
006 Carbon Cetrachloride
007 Chlorobenzene
009 Hexachlorobenzene
010 1,2-dichloroethane
Oil 1,1,1-trichloroethane
012 Hexachloroethane
013 1,1-dichloroethane
014 1,1,2-trichloroethane
015 1,1,2,2-tetrachloroethane
016 Chloroethane
017 Bis(chloromethyl)ether
018 Bis(2-chloroethyl)ether
019 2-chloroethyl vinyl ether
020 2-chloronaphthalene
021 2,4,6-trichlorophenol
022 Farachlormeta creaol
023 Chloroform
024 2-chlorophenol
025 1,2-dichlorobenzene
026 1,3-dichlorobenzene
027 1,4-dichlorobenzene
028 3,3'-dichlorobenridine
029 1,1-dichlroehtylene
030 1,2-trana-dichloroehtylene
031 2,4-dichlorophenol
032 1,2-dichloropropane
033 1,2-dichloropropylene
034 2,4-diaethylphenol
035 2,4-dinitrotoluene
036 2,6-dinitrotoluene
037 1,2-diphenylhydrazine
038 Ethylbenzene
039 Fluoranthene
040 4-chlorophenyl phenyl ether
041 4-broaophenyl phenyl ether
042 Bii(2-chloroisopropyl)ether
043 Bis(2-chloroethoxy)methane
044 Methylene chloride
045 Methyl chloride
046 Methyl brotaide
047 Broaofora ,
048 Dichlorobromomethane
*Removal Rating Priority Pollutant
H
L
L
M
H
M
H
H
M
M
H
M
M
H
L
-
M
L
H
H
H
L
H
H
H
H
H
L
L
H
M
M
H
H
H
H
M
H
H
H
M
M
L
L
L
H
M
049
050
051
052
053
054
055
057
058
059
060
061
062
063
064
065
066
067
068
069
070
071
072
073
074
075
076
077
078
079
080
081
082
083
084
085
086
087
088
106
107
108
109
110
111
112
Trichlortofluorome thane
Dichlorodifluorome thane
Chlorodibromome thane
Hexachlorobutadiene
Hexachlotocyclopentadiene
Isophorone
Naphthalene
2-nitrophenol
4-ni trophenol
2 , 4-dini tr opheno 1
4 , 6-dini.tro-o-cresol
N-nitrosodimethylamine
N— ni trosodipheny lamine
N-nitrodpsi-n-propylamine
Pen t ach loropheno 1
Phenol
Bis(2-ethylhexyl)phthalate
Butyl benzyl phthalate
Di-n-butyl phthalate
Di-n-octyl phthalate
Diethyl phthalate
Dimethyl phthalate
(a) Antharacene
Benzo(a)pyrene
3 , 4-benzpf luoranthene
Benzo ( k) f luoranthene
Chrysene
Acenaphthylene
Anthracene
Benzo(ghi)-perylene
Fluorene
Phenanthrene
Dibenzo ( a , h ) anthracene
Ideno ( 1 , 2 , 3-cd ) pyr ene
Pyrene
TetrachlOroethylene
Toluene
Trichloroethylene
Vinyl chloride
PCB-1242
PCB-1254
PCB-1221 .
PCB-1232
PCB-1248
PCB-1260
PCB-1016
*Removal Rating
M
L
M
H
H
H
H
H
H
H
H
M
H
M
H
M
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
M
M
L
L
H
H
H
H
H
H
H
^Explanation of Removal Ratings:
Category H (high removal)
Adsorbs at levels £100 mg/g carbon at Cf -.10 mg/1
Adsorbs at levels £100 mg/g carbon at C^ <1.0 mg/1
Category H (moderate removal)
Adsorbs ac levels £100 mg/g carbon at Cf » 10 mg/1
Adsorbs at levels £100 mg/g carbon at C* >1.0 mg/1
Category L (low removal)
Adsorbs at levels >100 mg/g carbon at C£ - 10 mg/1
Adsorbs at levels >10 mg/g carbon at Cf <1.0 mg/1
Cg « final concentrations of priority pollutant at equilibrium
512
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•TABLE VII-24
CLASSES OF ORGANIC COMPOUNDS ADSORBED ON CARBON
Organic Chemical Class
Aromatic Hydrocarbons
Polynuclear Aromatics
Chlorinated Aromatics
Phenolics ; - .'•-_..
Chlorinated Phenolics
High Molecular Weight Aliphatic and
Chlorinated Aliphatic Hydrocarbons
High Molecular Weight Aliphatic Acids
High Molecular Weight Aliphatic Amines
High Molecular Weight Ketones, Esters,
Surfactants
Soluble Organic Dyes
Examples of Chemical
Class -.-••;
benzene, toluene, xylene
naphthalene, anthracene
biphenyls
chlorobenzene, polychlorinated
biphenyls, aldrin, endrin,
toxaphene, DDT
phenol, eresol, resourcinol
and polyphenyls
trichlorophenol, pentachloro-
phenol
gasoline, kerosene Branch
Chain Hydrocarbons
carbon tetrachloride, perchloroethylene
tar acids, benzoic acid
and Aromatic Acids
aniline, diamines and Aromatic .
Amines
hydroquinone, polyethylene
Ethers and Alcoholsglycol
alkyl benzene sulfonates
'methylene blue, indigo
carmine
High Molecular Weight includes compounds in the range of from 4 to 20 carbon
atoms.
513
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Table VII-25
ULTRAFILTRATION PERFORMANCE
Parameter
Oil (freon extractable)
COD
TSS
Total Solids
Feed (mq/1)
1230
8920
1380
2900
Permeate (mq/1)
4
148
13
296
The removal percentages shown are typical, but they can be
influenced by pH and other conditions. The high TSS level is
unusual for this technology and ultrafiltration is assumed to
reduce the TSS level by one-thrid after mixed media filtration.
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.
Advantages and Limitations. Ultrafiltration is sometimes an
attractive alternative to chemical treatment because of lower
capital equipment, installation, and operating costs, very high
oil 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 ultraf iltration for th|e treatment of pro.cess
effluents is its narrow temperature range (18° to 45°C) for
satisfactory operation. Membrane life decreases with higher
temperatures, but flux increases at elevated temperatures.
Therefore, surface area requirements i 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. Strojng 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.
514
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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 re-
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 often necessary "to occasionally 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: In this category ultrafiltration is used
primarily to remove or recover liquid constituents of process
wastewaters. The system reject (concentrated oils) could be
recovered, reprocessed, or removed for disposal.
Demonstration 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. This technology is demonstrated in the: aluminum
die lube process segment.
16. 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 VI1-23.
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.
515
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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 waste water 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
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.
IN-PLANT TECHNOLOGY [
The intent of in-plant technology (i.e., recycle or reuse) for
the metal molding and casting industry point source category is
to reduce or eliminate the waste load requiring end-of-pipe
treatment or to reduce or eliminate the discharge of process or
516
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treated wastewaters. By incorporating recycle prior to
treatment, the efficiency of ': -an existing wastewater treatment
system is improved or the requirements of a new treatment system
are reduced.
The recycle or reuse of process wastewater is a particularly
effective technique for the reduction of both pollutant
discharges and treatment costs. The term "recycle" is used to
designate the return of process wastewater to the process or
processes from which it originated, while "reuse" refers to the
use of waste;water from one process in another. Both recycle and
reuse of process wastewater are presently practiced at battery
manufacturing plants although recycle is more extensively used.
The most frequently recycled waste streams are the air pollution
control scrubber discharges, and wastewater from equipment and
area cleaning.
Both recycle and reuse are frequently ppossible with only simple
treatment (i.e., primary sedimentation. Recycle or reuse in
these instances yields cost savings by reducing the volume of
wastewater requiring treatment. Where treatment is required for
recycle or reuse, it is frequently simpler than the treatment
necessary to achieve effluent quality suitable for release to the
environment, 'treatment prior to recycle or reuse observed in
present practice is generally restricted to simple settling or
neutralization. Since these treatment practices can be less
costly than those used prior to discharge, economic as well as
environmental benefits are usually realized. In addition to
these in-process recycle and reuse practices, some plants are
observed to return part or all of the treated effluent from an
end-of-pipe,treatment system for further process use.
The extent of- recycle possible in most process water uses is
ultimately limited by the increasing concentrations of dissolved
solids in the water. The buildup of dissolved salts generally
necessitates some small discharge or "blowdown" from the process
to treatment. In some cases, the rate of addition of dissolved
salts may be sufficiently, low to be balanced by removal of
dissolved solids in water entrained in settled solids. In these
cases, complete recycle with no wastewater discharge can be
achTevear-In other cases, a accumulated scale may be abraded by
the particulate matter suspended in the recycled wastewaters.
Water Use Reduction - The volume of wastewater discharged from a
plant or specific process operation may be reduced by simply
eliminating excess flow and unnecessary water use. Often this
may be accomplished with little or no change in the manufacturing
process or equipment and without any capital expenditure. A
comparison of the volumes of process water used in and discharged
517
-------
from equivalent process operations at different foundries or on
different days at the same foundry indicates numerous
opportunities for water use reductions. Additional reductions in
process water use and discharge may be achieved by modifications
to process techniques and equipment.
Many production units in foundry operations were observed to
operate intermittently or at highly variable production rates.
The practice of shutting off process water flow during periods
when the unit is not operating and of adjusting flow rates during
periods of low production can prevent much unnecessary water use.
Water may be shut off and controlled^ manually or through
automatically controlled valves. Manual adjustment involves the
human factor and has been found to be;somewhat unreliable in
practice; production personnel often fail! to turn off manual
valves when production units are shut down and tend to increase
water flow rates to maximum levels "to ensure good operation"
regardless of production activity. Automatic shut off valves may
be used to turn off water flows when production units are
inactive. Automatic adjustment of flow rates according to
production levels requires more sophisticated control systems.
i
Additional flow reductions may be achieved by the implementation
of more effective water use in some process operations. These
measures generally require the purchase or modification of some
process equipment and involve larger capital investment than the
simple flow control measures discussed above.
518
-------
1 1 t J J 1 1
2 3
10 11 12 13
FIGURE VI1-1 COMPARATIVE SOLUBILITIES OF METAL HYDROXIDES
AND SULFIDE AS A FUNCTION OF pH
519
-------
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U
t
LU
2
2
Z
(A
o
<
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u
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u
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3
(n/ow)
M
ONIZ
520
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0.40
SODA ASH AND
CAUSTIC SODA
8.0
10.3
FIGURE VII-3 LEAD SOLUBILITY IN THREE ALKALIES
521
-------
EFFLUENjTR
Uf
INFLUENT
ALUM
I
u
It
WATER
LEVEL
STORED
BACKWASH
WATER
••—•—FILTER—
-TJBACKWASH*-
POLYMER
FILTER \ FILTER
COMPARTMENT \ MEDIA
COLLECTION CHAMBER
I
•"•': *.**'*"'•' * c Q JL L
• ••«.". •. •. ; . ^ ^»**^^
u uu
THREE WAY VALVE
FIGURE VI|4 GRANULAR BED FILTRATION
522
-------
PERFORATED
BACKING PLATE
FABRIC
FILTER MEDIUM
SOLID
RECTANGULAR
END PLATE
INLET
SLUDGE
FABRIC
FILTER MEDIUM
ENTRAPPED SOLIDS
FILTERED LIQUID OUTLET
\
PLATES AND FRAMES ARE
PRESSED TOGETHER DURING
FILTRATION CYCLE
RECTANGULAR
METAL PLATE
RECTANGULAR FRAME
FIGURE T7TT-.fi PRESSURE FILTRATION
523.
-------
SEDIMENTATION BASIN
INLET ZONE
BAFFLES TO MAINTAIN ,
QUIESCENT CONDITIONS •
OUTLET ZONK
INLET LIQUID
i^, * SETTLING PARTICLE
• •*-*!• TRAJECTORY . «
OUTLET LIQUID
t
BELT-TYPE SOLIDS COLLECTION
MECHANISM
SETTLED PARTICLES COLLECTED
AND PERIODICALLY REMOVED
CIRCULAR CLARIPIER
INLET LIQUID
CIRCULAR BAFFLE
SETTLING ZONE
ANNULAR OVERFLOW WEIR
OUTLET LIQUID
REVOLVING COLLECTION
MECHANISM
SETTLING PARTICLES
SETTLED PARTICLES
COLLECTED AND PERIODICALLY
REMOVED
SLUDGE DRAWOFF
FIGURE VII- 6 REPRESENTATIVE TYPES OF SEDIMENTATION
524
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FLANGE
WASTE WATER
INFLUENT
DISTRIBUTOR
WASH WATER
SURFACE WASH
MANIFOLD
BACKWASH
BACKWASH
REPLACEMENT CARBON
CARBON REMOVAL PORT
TREATED WATER
SUPPORT PLATE
FIGURE VII-J.6 ACTIVATED CARBON ADSORPTION COLUMN
534
-------
CONVEYOR DRIVE i OWYINC
LIQUID
OUTLET
SLUDGE
INUET
CYCLO6EAR
DISCHARGE
CONVEYOR
•OWL
RINO
IMPELLER
FIGURE VTI- 17
CENTRIHJGA.TI£K
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WATER
DISCHARGE
OILY WATER
INFLUENT
OVERFLOW
SHUTOFF
VALVE
EXCESS
AIR OUT
LEVEL
CONTROLLER
TO SLUDGE
TANK
FIGURE 3ZH-I9 DISSOLVED AIR FLOTATION
537
-------
CONDUIT
TO MOTOR
INFLUENT
CONDUIT TO
OVERLOAD
ALARM
EFFLUENT PIPE
EFFLUENT CHANNEL
PLAN
INFLUENT
TURNTABLE
BASE
HANDRAIL
STILTS
CENTER SCRAPER
CENTER COLUMN
CENTER CAGE
WEIR
SQUEEGEE
FIGURE 2EL-20 GRAVITY THICKENING
538
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3-IN. COARSE SAND
3-IN. FINE GRAVEL
3-IN. MEDIUM GRAVEL
3 TO « IN. COARSE GRAVEL
PIPE COLUMN FOR
GLASS-OVER
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6-IN. UNDERDRAIN LAID-
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SECTION A-A
FIGURE VIT-PI SLUDGE DRYING BED
539
-------
ULTRAF1LTRATION
MACROMOLECULES
P * IO-SO PSI
MEMBRANE
WATER SALTS
-MEMBRANE
PERMEATE
• O ~ • O
FEED n 00 . »
O i* CONCENTRATE
|
1
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I
• DISSOLVED SALTS AND LOW-MOLECULAR-WEIGHT ORGANICS
FIGURE 3ZLT-22 SIMPLIFIED ULTRAFILTRATION
540
FLOW SCHEMATIC
-------
FABRIC OR WIRE
FILTER MEDIA
STRETCHED OVER
REVOLVING DRUM
ROLLER
DIRECTION OF ROTATION
VACUUM
SOURCE
SOLIDS SCRAPED
OFF FILTER MEDIA
STEEL
CYLINDRICAL
FRAME
LIQUID FORCE
THROUGH
MEDIA BY
MEANS OF
VACUUM
SOLIDS COLLECTION
HOPPER
INLET LIQUID
TO BE
FILTERED
-TROUGH
FILTERED LIQUID
FIGURE 301-23 VACUUM FILTRATION
•- 541.
U.S. GOTEBSHENT EHINIIHB OPFIOE I 1982 0-381-085/4486
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