-------
b. Nalntalnability: Deep bed filters may be operated with
either manual or automatic backwashing. In either
case, they must be periodically inspected for media
retention, partial plugging and particulate leakage.
pemonstratiQn Status
Filtration is one of the more common treatment methods used
for steel industry wastewatet;- especially in the hot forming
subcategory. This technology is used to treat a variety of
wastewaters with similar results. Its ability to reduce the
amount of solids, oils and metals in the wastewater is well
demonstrated with both short and long-term data in the steel
industry.
Oil Removal
Oils and greases are removed from process wastewaters by several
methods in the, steel industry including oil skimming, filtration,
and air flotation. Also, ultraf iltration is used at one cold
rolling plant to remove oils. Oils may also be incidentally
removed through other treatment processes such as clarification.
The source of these oils is usually lubricants and preservative
coatings used in the various steelmaking and finishing
operations.
As a general matter, the most effective first step in oil removal
is to prevent the oil from .•nixing with the large volume
wastewater flows by segregating the sumps in all cellars and by
appropriate maintenance of the lubrication and greasing systems.
If the segregation is accomplished, more efficient removals of
the oils ar.d greases from wastewaters can be accomplished. The
oil removal equipment used in the steel industry is described
below.
1 . Skimming
Pollutants with a specific gravity less than water will
often float unassisted to the surface of the wasfcewater
Skimming is used tc remove 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 there! 01 e suited to the removal of
nonemulsif ied oils from untreated wastewatfrrs. Corroion
skimming mechanisms include the rotating drum type, which
oil from the surface of the water as the drum
A doctor blade ^crapes oil from the drum and
it in a trough for disposal or reuse. The water
is allowed to flow under the rotating drum. An
baffle is usually ins:alled after the drum; this
picks up
rotates.
collects
portion
underflow
oil which
is pulled
has the advantage of retaining any floating
escapes the drum skimmer. The belt type skxmmer
-------
vertically through the water, collecting oil which is then
scraped off from the belt surface and collected in a storage
tank. The industry also uses rope and belt skimmers of
various design that function in the same fashion. Gravity
separators, such as the API type, use overflow and underflow
baffles to skim a layer of floating oil 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 most 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.
Application and Performance
Skimming may be used on any wastewater containing pollutants
which float to the surface. It is commonly used to remove
free oil, grease, and soaps. Skimming is always used with
air flotation and often with clarification to improve
removal of both settling and floating materials.
The removal efficiency of a skimmer is a function of the
density of the material to be floated and the retention time
of the wastewater in the tank. The retention time required
to allow phase separation and subsequent skimming varies
from 1 to 15 minutes, depending upon 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 fairly high and consistent. Drum and
belt type skimmers are suitable where oil can be allowed to
collect in a treatment device for periodic or continuous
removal. Data for various oil skimming operations are
presented in Appendix A.
Advantages and Limitations
Skimming as 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 treatment.
Therefore, skimming alone may not remove all the pollutants
capable of being removed by air flotation or other more
sophisticated technologies.
106
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Operational Factors
a. Reliability: Because of its simplicity, skimming is a
very reliable technique. During cold weather, heating
is usually required for the belt-type skimmers.
b. Maintainability: The skimming mechanism requires
periodic lubrication, adjustment, and replacement of
worn parts.
Demonstration Status
Skimming is a common method used to remove floating oil in
many industrial categories, including the steel industry.
Skimming is used extensively to treat wastewaters from hot
forming, continuous casting, and cold forming operations.
2. Filtration
As explained above, filtration is also used to remove oils
and greases from steel industry wastewaters. The mechanism
for removing oils is very similar to the solids removal
mechanism. The oils and greases, either floating or
emulsified types, are directed into the filter where they
are adsorbed on the filter media. Significant oil
reductions can be achieved with filtration, and problems
with the oils are not experienced unless high concentrations
of oils are allowed to reach the filter bed. When this
occurs the bed can be "blinded" and must be backwashed
immediately. If too much oil is in the filter wastewater,
frequent backwashing is necessary which makes the use of the
technology unworkable. Therefore, proper pretreatment is
essential for the proper operations of filtration equipment.
Application and Performance
The discussion presented above for filtration systems
applies here as well. The filter will reduce oil from
moderate levels down to extremely low levels. Long-term
data for eight filtration systems demonstrate that an oil
and grease performance standard as low as 3.5 mg/1 can be
readily attained on a 30-day average basis and 10 mg/1 oil
and grease can be readily attained on a daily maximum basis.
However, because of problems with obtaining consistent
analytical results in the range of 5 mg/1, the Agency has
decided to establish only a maximum effluent limitation and
standard based upon a daily maximum concentration of 10 mg/1
for hot forming operations and other operations with similar
wastewaters.
Operational Factors and Demonstrated Status
See prior discussion on filtration.
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3. Flotation
Flotation is a process which causes particles such as metal
hydroxides or oils to float to the surface of a tank where
they are concentrated and removed. Gas bubbles are released
in the wastewater and attach to the solid particles, which
increase their buoyancy and causes them to float. In
principle, this process is the opposite of sedimentation.
Flotation is used primarily in the treatment of wastewaters
that carry finely divided suspended solids or oil. Solids
having a specific gravity only slightly greater than 1.0,
which require abnormally long sedimentation times, may be
removed 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. For example, acid and chemical aids are often used
to break oil emulsions in cold rolling wastewaters. The
emulsions are part of rolling solutions used in the process.
Emulsion breaking is necessary for proper treatment of most
cold rolling wastewaters by flotation.
The principal difference between types of flotation
techniques is the method of generating the minute gas
bubbles (usually air) needed to float the "oil. Chemicals
may be used to improve the' efficiency of any of the basic
methods. The different flotation techniques and the method
of bubble generation for each process are described below.
Froth .Flotation: Froth flotation is based upon the
differences in the physiochemical properties of various
particles. Wetability and surface properties affect
particle affinity to gas bubbles. In froth flotation, air
is blown through the solution containing flotation reagents.
The particles with water repellent surfaces stick to air
bubbles 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 watrr 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 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 as a result of the release of air from
a supersaturated solution under relatively high pressure.
ice
-------
There are two types of contact between the gas bubbles and
particles. The first 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. This is the predominant type of
contact. The second type of contact is one of adhesion.
Adhesion results from the intermolecular attraction exerted
at the interface between the solid particle and gaseous
bubble.
Vacuum Flotation: This process consists of saturating the
wastewater with air, either directly in an aeration tank or
by permitting air to enter the suction of a pump. A partial
vacuum causes the dissolved air to come out of solution as
minute bubbles. The bubbles attach to solid particles and
form a scum blanket on the surface, which is normally
removed by a skimming mechanism. Grit and other heavy
solids which 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 alpo under partial vacuum.
Application and Performance
Flotation is commonly used to treat cokemaking and cold
forming wastewaters. Gas (hydrogen) flotation is used at
several cokemaking operations to control oil levels.
Dissolved air flotation is used extensively to treat cold
rolling wastewaters. The flotation process is used after
emulsion breaking and prior to final settling. Data for
three steel industry flotation units are presented below.
Performance of Flotation Units
Oil & Grease (mq/1)
Plant In Out
0684F (cokemaking) 93 45
0684F (cold rolling) NA 7.3
0060B 41,140 98
Advantages and Limitations
The advantages of the flotation process include the high
levels of solids and oil separation which are achieved in
many applications; relatively low energy requirements; and,
the capability to adjust air flow to meet the varying
requirements of treating different types of wastewaters.
The limitations of flotation are that it often requires
189
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addition of chemicals to enhance process performance; it
requires properly trained and attentive operators; and it
generates large quantities of solid wastes.
Operational Factors
a. Reliability: The reliability of a flotation system is
normally high and is governed by proper operation of
the sludge collector mechanism and by the motors and
pumps used for aeration.
b. Maintainability: Maintenance of the scraper blades
used to remove the floated material is critical for
proper operations. 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.
Demonstration Status
Flotation is extensively demonstrated in the steel industry,
particularly for the treatment of cokemaking and cold
rolling wastewaters.
4. Ultrafiltration
Ultrafiltration (UF) includes the use of pressure and
semipermeable polymeric membranes to separate emulsified or
colloidal materials suspended in a liquid phase. The
membrane of an ultrafiltration unit forms a molecular screen
which retains molecular particles based upon their
differences in size, shape, and chemical structure. The
membrane permits passage of solvents and lower molecular
weight molecules. At present, Ultrafiltration systems are
used to remove materials with molecular weights in the range
of 1,000 to 100,000 and particles of comparable or larger
sizes.
In. the Ultrafiltration process, the wastewater 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.
Application and Performance
Ultrafiltration has potential application in cold rolling
operations for separating oils and residual solids from the
process wastes. Because of the ability to remove emulsified
oils with little or no pretreatment, Ultrafiltration is well
190
.X
-------
suited for many of the wastewaters generated at cold rolling
mills. Also, some organic compounds of suitable molecular
weight may be bound in the oily wastes which are removed.
Hence, ultrafiltration could prove to be an effective means
to achieve toxic organic pollutant removal for the cold
rolling subdivision.
The following test data depict ultrafiltration performance
for the treatment of cold rolling wastewaters at one plant:
UHrafiltration Performance
Feed (mg/1) Permeate (mg/1)
Oil (freon extractable) 82,210 140
TSS 2,220 199
Chromium 6.5 1.2
Copper 7.5 0.07
2-chlorophenol 35.5 ND
2-nitrophenol 70.0 0.02
When the concentration of pollutants in the wastewater is
high (as above) the ultrafiltration unit alone may not
adequately treat the wastewater. Additional treatment may
be required prior to discharge.
Advantages and Limitations
Ultrafiltration is an attractive alternative to chemical
treatment in certain applications because of lower
installation and operating costs, high oil and suspended
solids removal, and little required pretreatment. It places
a positive barrier between pollutants and effluent which
reduces the possibility of extensive pollutant discharge due
to operator error or upset in settling and skimming systems.
Another possible application is recovering alkaline values
from alkaline cleaning solutions.
A limitation on the use of ultrafiltration for treating
wastewaters is its narrow temperature range (18 to 30
degrees C) for satisfactory operation. Membrane life is
decreased with higher temperatures, but flux increases at
elevated temperatures. Therefore, the surface area
requirements are a function of temperature and become a
tradeoff between initial costs and replacement costs for the
membrane. Ultrafiltration is not suitable for certain
solutions. Strong oxidizing agents, solvents, and other
organic compounds can dissolve the membrane. Fouling is
sometimes a problem, although the high velocity of the
wastewater normally creates enough turbulence to keep
fouling at a minimum. Large solids particles are also
sometimes capable c: puncturing the membrane and must be
191
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removed by gravity settling or filtration prior to
ultrafiltration.
Operational Factors
a. Reliability: The reliability of ultrafiltration
systems is dependent upon the proper filtration,
settling or other treatment of incoming wastewaters to
prevent damage to the membrane. Pilot studies should
be completed for each application to determine
necessary pretreatment steps and the specific membrane
to be used.
b. Maintainability: A limited amount of regular
maintenance is required for the pumping system. In
addition, membranes must be periodically changed. - The
maintenance associated with membrane plugging can be
reduced by selecting a membrane with optimum physical
characteristics and providing sufficient velocity of
the wastewater. It is necessary to pass a detergent
solution through the system at regular intervals to
remove an oil and grease film which accumulates on the
membrane. With proper maintenance membrane life can be
greater than twelve months.
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. Over TOO units are presently in operation in
the United States. Ultrafiltration is demonstrated in the
steel industry in the cold forming subcategory.
Metals Removal
Steel industry wastewaters contain significant levels of toxic
metal pollutants including chromium, copper, lead, nickel, zinc
and others. These pollutants are generally removed by chemical
precipitation and sedimentation or filtration. Most can be
effectively removed by precipitating metal hydroxides or
carbonates through reactions with lime, sodium hydroxide, or
sodium carbonate. Sodium sulfide, ferrous sulfide, or sodium
bisulfite can also be used to precipitate metals as sulfide
compounds with low solubilities.
Hexavalent chromium is generally present in galvanizing and
oxidizing salt bath descaling wastewaters. Reduction of this
pollutant to the trivalent form is required if precipitation as
the hydroxide is to be achieved. Where sulfide precipitation is
used, hexavalent chromium can be reduced directly by the sulfide.
Chromium reduction using sulfur dioxide or sodium bisulfite or by
192
„ ' 1
-------
n
electrochemical techniques may be necessary, however, when
hydroxides are precipitated.
Details on various metal removal technologies are presented below
with typical treatability levels where data are available.
1. Chemical Precipitation
Dissolved toxic metal ions and certain anicns may be
chemically precipitated and removed by physical means such
as sedimentation, filtration, or centrifugation. Several
reagents are commonly used to effect this precipitation.
a. 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.
b. 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.
c. 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, a presettling tank, or directly to a
clarifier or other settling device. Coagulating agents may
be added to facilitate settling. After the solids have been
removed, a 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 made up of at least two
steps: precipitation of the unwanted metals and removal of
the precipitate. A 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, the solubility of the metal and
co-precipitation effects. The effectiveness of this method
of removirir; any specific metal depends on the fraction of
the specific metal in the raw waste (and hence in the
precipitate) and the effectiveness of suspended solids
removal.
Application and Performance
Chemical precipitation is used extensively in the steel
industry for precipitation of dissolved metals including
193
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aluminum, antimony, arsenic, beryllium, cadmium, chromium,
cobalt, copper, iron, lead, manganese, mercury, molybdenum,
nickel, tin, and zinc. The process is also applicable to
any substance that can be transformed into an insoluble form
such as fluorides, phosphates, soaps, sulfides, and others.
Chemical precipitation is simple and effective.
The performance of chemical precipitation depends on several
variables; the most important are:
a. Maintenance of an alkaline pH throughout the
precipitation reaction and subsequent settling.
b. Addition of a sufficient excess of treatment ions to
drive the precipitation reaction to completion.
c. Addition of an adequate supply of sacrifleal ions (such
as iron or aluminum) to ensure precipitation and
removal of specific target ions.
d. Effective removal of precipitated solids (see
appropriate technologies discussed under "Solids
Removal").
A discussion of the performance of some of the chemical
precipitation technologies used in the steel industry is
presented below.
Lime Precipitation - Sedimentation Performance
Lime is sometimes used in conjunction with sedimentation
technology to precipitate metals. Numerous examples of this
technology are demonstrated in the steel industry, mostly
for treatment of steel finishing wastewaters. Data for one
plant and the median effluent concentration of long term
averages for several plants using this technology are shown
below. Plant 0584E has a lime precipitation/sedimentation
treatment system which treats wastewaters from several
finishing operations, including electroplating which is not
covered as part of the steel industry category. The median
data for the other plants were used to establish the
effluent limitation for carbon steel finishing operations
and are review in Appendix A of this volume.
194
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Lime Precipitation - Sedimentation Performance
Pollutant
Concentration of Pollutants
(mq/1)
Median
Performance*
Dissolved Iron
Chromium
Copper
Lead
Nickel
Tin
Zinc
TSS
PH
Plant 0584E
In Out
0.25
4.4
Out
4.4
0.11
322
2.9-6.8
0.01
0.054
—
-
-
0.0
0.02
4.5
7.0-7.4
<0.02
0.03
0.04
0.10
0.15
—
0.06
25
6.0-9.
0
*See Appendix A
Lime Precipitation - Filtration Performance
A metals removal technology that is used in the steel
industry similar to the lime/sedimentation system includes
lime precipitation and filtration. These systems accomplish
better solids and oil removal and also achieves slightly
better control of the effluent concentration of the metallic
elements. Data for two plants that employ lime
precipitation/filtration technology are shown below.
Pickling and galvanizing wastewaters are treated at plant
0612, while pickling, galvanizing and alkaline cleaning
wastewaters are treated at plant 01121. The median effluent
concentrations of long term average for several plants which
were used to establish the effluent limitations for
filtration systems are also presented below. These effluent
data are more thoroughly, reviewed in Appendix A of this
volume. Pilot plant data for steelmaking wastewaters are
also presented in Appendix A.
195
1
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-~—
Lime Precipitation - Filtration Performance
Concentration of
(mq/1)
Pollutants
Pollutant
Chromium
Copper
Lead
Nickel
Zinc
TSS
PH
Plant 0612
Plant 01121
Out
Out
1 .60
0.60
2.400
0.60
285.00
350.00
2.9-
3.9
0.04
0.08
0. 18
0.02
0.12
11.00
8.3-
8.5
0.12
0.17
C.19
0.08
18.00
199.00
5.2-
5.6
0.03
0.02
<0. 10
0.03
0.13
1.00
7.3-
7.7
Median
Performance*
Out
0.03
0.03
0.06
0.04
0.10
9.8
6.0
9.0
*See Appendix A
Sulfide Precipitation
Most metal sulfides are less soluble than hydroxides and the
precipitates are frequently more dependably removed from
water. Solubilities for selected metal hydroxides and
sulfide precipitates are shown below:
Theoretical Solubilities of Hydroxides and Sulfides
of Heavy Metals in Pure Water
Metal
Cadmium(Cd+2)
Chromium (Cr*J)
Copper (Cu+2)
Iron (Fe+z)
Lead (Pb+2)
Nickel (Ni+z)
Silver (Ag+2)
Tin (Sn+2)
Solubility of Metal, mq/1
As hydroxide
2.3
8.4
2.2
8.9
2.1
6.9
13.0
1 .1
x
x
X
X
X
X
X
X
10-*
10-*
10-z
io-»
io-°
io-j
io-°
io-«
As sulfide
6.7 x ID-*0
No precipitate
5.8 x 10-»«
3.4 x 10-*
3.8 x 10-'
6.9 x 10-«
7.4 x 10-»2
2.3 x 10~7
Sulfide treatment has not been used in the steel industry on
a full-scale basis. However, it has been used in other
manufacturing process (e.g. electroplating) to remove metals
from wastewaters with similar characteristics and pollutants
to those of the steel industry.
In assessing whether this technology is transferable for use
in steel industry, the Agency consulted numerous references;
contacted sulfide precipitation equipment manufacturers, and
gathered data from operating sulfide precipitation systems.
The wastewaters treated by these sulfide precipitation
systems were contaminated with many of the same toxic metals
196
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found in steel industry wastewaters and at similar
concentrations. Accordingly, the Agency concluded that a
transfer of the effectiveness of this technology is
possible. However, as noted above there are no full scale
systems currently in use in the steel industry.
Data for several sulfide/filtration systems are shown below.
Sulfide Precipitation/Filtration Performance
Concentration of Pollutants (mq/1)
Pollutant
Chromium
Iron
Nickel
Zinc
TSS
PH
Data Set II
In Out
Data Set ft2
2.0
85.0
0.6
27.0
320
2.9
0.04
0.10
4.6
8.2
In
2.4
108
0.68
33.9
Out
0.60
<0. 1
7.7 7.4
Another benefit of the sulfide precipitation technology is
che ability to precipitate hexavalent chromium (Cr+»)
without prior reduction to the trivalent state as is
required in the hydroxide process. When ferrous sulfide is
used as the precipitant, iron and sulfide act as reducing
agents for the hexavalent chromium according to the
reaction:
Cr04= + FeS «• 4H,0-»Cr(OH)3 + Fe(OH), * S * 20H-
In this reaction, the sludge produced consists mainly of
ferric hydroxides, chromic hydroxides and various metallic
sulfides. Some excess hydroxyl ions are generated in this
process, possibly requiring a downward pre-adjustment of pH.
Advantages and Limitations
Chemical precipitation is an effective technique for
removing many pollutants from industrial wastewaters. It
operates at ambient conditions and is well suited to
automatic control. The use of chemical precipitation may be
limited due to interference of chelating agents, chemical
interferences from mixing wastewaters and treatment
chemicals, and potentially hazardous situations involved
with the storage and handling of those chericals. Lime is
usually added as a slurry when used in hydroxide
precipitation. The slurry must be well mixed and the
addition lines periodically checked to prevent fouling. In
addition, hydroxide precipitation usually makes recovery of
the precipitated metals difficult, because of the
heterogeneous nature of most hydroxide sludges. As shown
m
^S",
1
197
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above, lime precipitation of steel industry finishing
wastewaters can produce effluent quality similar to that
shown for sulfide precipitation.
The low solubility of most metal sulfides, allow for high
metal removal efficiencies. Also, the sulfide process has
the ability to remove chromates and dichromates without
preliminary reduction of the chromium to the trivalent
state. Sulfide precipitation can be used to precipitate
metals complexed with most coit.plexing agents. However,
Sulfids precipitation can be used to care must be taken to
maintain the pH of the solution at approximately 10 in order
to prevent the generation of toxic sulfide gas during this
process. For this reason ventilation of the treatment tanks
may be a necessary precaution in most installations. The
use of ferrous sulfide reduces or virtually eliminates 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. Where excess sulfide is present, aeration of the
effluent stream can aid in oxidizing residual sulfide to the
less harmful sodium sulfate (Na2S04). The cost of sulfide
precipitants is high' in comparison 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 sulfide is used as the precipitant.
Sulfide precipitation may be used as a final tratement step
after hydroxide precipitation-sedimentation. This treatment
configuration may provide the better treatment effectiveness
of sulfide precipitation while minimizing the variability
caused by changes in raw waste and reducing the amount of
sulfide precipitant required.
Operational Factors
a. Reliability: The reliability of alkaline chemical
precipitation is high, although proper monitoring and
control are necessary. Sulfide precipitation systems
provide similar reliability.
b. 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
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for the efficient operation of
precipitation-sedimentation systems.
Demonstration Status
Chemical precipitation of metal hydroxides is a classic
wastewater treatment technology used throughout the steel
industry. Chemical precipitation of metals in the carbonate
form alone has been found to be feasible and, is used in
commercial application to permit metals recovery and water
reuse. Full scale commercial sulfide precipitation units
are in operation at numerous installations, however, none
are presently installed in the steel industry.
2. Filtration (for Metal Removal)
As discussed previously, filtration is a proven technology
for the control of suspended solids and oil and grease. The
filtration mechanism which reduces the concentrations of the
suspended solids and oils also treats the metallic elements
present in particulate form. To determine the treatability
levels for metals using filtration the Agency compiled all
available data for such systems. Data for seventeen
filtration systems were averaged to develop the treated
effluent concentrations. The average treated effluent
concentrations and the proposed monthly average
concentration for five toxic metals are shown below:
Metal Removal with Filtration Systems
Monthly Average Daily Maximum
Pollutant Concentration (mg/1) Concentration (mg/1)
Chromium 0.04 0.12
Copper 0.04 0.12
Lead 0.08 0.24
Nickel 0.05 0.16
Zinc 0.08 0.24
For purposes of developing effluent limitations, the Agency
is using 30 day average concentrations of 0.10 mg/1 and
daily maximum concentrations of 0.30 mg/1 for each toxic
metal except zinc. For zinc, the Agency is using a 30 day
average concentration of 0.15 mg/1 and daily maximum
concentration of 0.45 mg/1, since the performance standard
for zinc was greater than 0.10 mg/1. The Agency rounded the
zinc performance standard to 0.15 mg/1. Reference is made
to Appendix A for development of toxic metals effluent
concentrations.
199
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Advantages and Limitations
See prior discussion on filtration systems.
Operational Factors and Demonstration Status
See prior discussion on filtration systems.
Organic Removal
Thirty-three organic toxic pollutants were detected in steel
industry wastewaters above treatability levels. Because some of
these pollutants are present in significant levels, the Agency
considered two demonstrated treatment alternatives for these
pollutants in several subcategories: carbon adsorption and
biological treatment (activated sludge). These technologies are
discussed separately below.
1. Carbon Adsorption
The use of activated carbon for removal of dissolved
organics from water and wastewater has been demonstrated and
is one of the most efficient organic removal processes"
available. Activated carbon has also been shown to be an
effective adsorbent for many toxic metals, including
mercury. This process is reversible, thus allowing
activated carbon to be regenerated and reused by the
application of heat and steam or solvent. 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 square meters/gram)
which result from a large number of internal pores. Pore
sizes generally range in radius from 10-100 angstroms.
Activated carbon removes contaminants from water by the
process of adsorption (the attraction and accumulation of
one substance on the surface of another). Activated carbon
preferentially adsorbs organic compounds and, because of
this selectivity, is particularly effective in removing
toxic organic pollutants from wastewaters.
Carbon adsorption requires pretreatment (usually filtration)
to remove excess suspended solids, oils, and greases.
Suspended solids in the influent should be less than 50 mg/1
200
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to minimize backwash requirements. A downflow carbon bed
can handle much higher levels (up to 2000 mg/1), but
frequent backwashing is required. Backwashing more than two
or three times a day is not desirable. Oil and grease
should be less than about 15 mg/1. A high level of dissolved
inorganic material in the influent may cause problems with
thermal carbon reactivation (i.e., scaling and loss of
activity) unless appropriate preventive steps are taken.
Such steps might include pH control, softening, or the use
of an acid wash on the carbon prior to reactivation.
Activated carbon is available in both powdered and granular
form. 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
Activated carbon has been used in a variety of applications
involving the removal of objectional organics from
wastewater streams. One of the more frequent uses is to
reduce the concentration of oxygen demanding substances in
POTW effluents. It is also used to remove specific organic
contaminants in the wastewaters of various manufacturing
operations such as petroleum refining. There are two full
scale activated carbon systems in use in the steel industry
for treating cokemaking wastewaters.
Tests performed on single compound systems indicate that
processing with activated carbon can achieve residual levels
on the order of 1 microgram per liter for many of the toxic
organic pollutants. Compounds which respond well to
adsorption include carbon tetrachloride, chlorinated
benzenes, chlorinated ethanes, chlorinated phenols,
haloethers, phenols, nitrophenols, DDT and metabolites,
pesticides, polynuclear aromatics and PCB's. Plant scale
systems treating a mixture of many organic compounds must be
carefully designed to optimize certain critical factors.
Factors which affect overall adsorption of mixed solutes
include relative molecular size, the relative adsorptive
affinities, and the relative concentration of the solutes.
Data indicate that column treatment with granular carbon
provides for better removal of organics than clarifier
contact treatment with powdered carbon.
Data from two activated carbon column systems used in the
steel industry and EPA treatability data for carbon
adsorption systems were combined to develop performance
standards for carbon column systems. The average
concentration values attainable with carbon adsorption
systems are shown in Table VI-1 for those toxic organics
201
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found above treatability levels in steel industry
wastewaters.
Advantages and Limitations
The major benefits of carbon treatment include applicability
to a wide variety of organics, and a high removal
efficiency. The system is not sensitive to fairly wide
variations in concentration and flow rates. The system is
compact, and recovery of adsorbed materials is sometimes
practical. However, the 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. When thermal regeneration is used,
capital and operating costs are generally economical when
carbon usage exceeds about 1,000 Ib/day. Carbon does not
efficiently remove low molecular weight or highly soluble
organic compounds.
Operational Factors
a. Reliability: This system is very reliable with proper
pretreatment and proper operation and maintenance.
b. Maintainability: This system requires periodic
regeneration or replacement of spent carbon and is
dependent upon raw waste load and process efficiency.
Demonstration Status
Carbon adsorption systems have been demonstrated to be
practical and economical for the reduction of COD, BOD and
related pollutants in secondary municipal and industrial
wastewaters; for the removal of toxic or refractory organics
from isolated industrial wastewaters; for the removal and
recovery of certain organics from wastewaters; and for the
removal, at times with recovery, of selected inorganic
chemicals from aqueous wastes. Carbon adsorption is
considered a viable and economic process for organic waste
streams containing up to 1 to 5 percent of refractory or
toxic organics. It also has been used to remove toxic
inorganic pollutants such as metals.
Granular carbon adsorption is demonstrated on a full scale
basis at tow plants in the cokemaking subcategory and one
blast furnace and sintering operation. Additionally, a
powered carbon addition study has been piloted for
biological treatment of cokemaking wasterwaters.
2. Biological Oxidation
Biological treatment is another method of reducing the
concentration of ammonia-n, cyanide, phenols (4AAP) and
202
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toxic organic pollutants from process wastewaters.
Biological systems, both single and two-stage, have been
used effectively to treat sanitary wastewaters. The
activated sludge system is well demonstrated in the steel
industry, although other systems including rotating
biological disks have also been studied.
In the activated sludge process, wastewater is stablized
biologically in a reactor under aerobic conditions. The
aerobic environment is achieved by the use of diffused or
mechanical aeration. After the wastewater is treated in the
reactor, the resulting biological mass is separated from the
liquid in a settling tank. A portion of the settled
biological solids is recycled and the remaining mass is
wasted. The level at which the biological mass should be
maintained in the system depends upon the desired treatment
efficiency, the particular pollutants that are to be removed
and other considerations related to growth kinetics.
The activated sludge system generally is sensitive to
fluctuations in hydraulic and pollutant loadings,
temperature and certain pollutants. Temperature not only
influences the metabolic activities of the microbiological
population, but also has an effect on such factors as gas
transfer rates and the settling characteristics of the
biological solids. Some pollutants are extremely toxic to
the microorganisms in the system, such as ammonia at high
concentrations and tocix metals. Therefore, sufficient
equalization and pretreatment must be installed ahead of the
biological reactor so that high levels of toxic pollutants
do not enter the system and "kill" the microorganism
population. If the biological conditions in an activated
sludge plant are upset, it can be a matter of days or weeks
before biological activity returns to normal.
Application and Performance
Although a great deal of information is available on the
performance of activated sludge units in controlling
phenolic compounds, cyanides, ammonia, and BOD, limited
long-term data are available regarding toxic pollutants
other than phenolic compounds, cyanides, and ammonia. Only
lately has there been an emphasis upon the performance of
the activated sludge units on the toxic organic pollutants.
Originally, advanced levels of treatment using a biological
system were expected to involve multiple stages for
accomplishing selective degradation of pollutants in series,
e.g., phenolic compounds and cyanide removal, nitrification,
and dentrification. The Agency sampled the wastewaters of
two well operated biological plants in the cokemaking
subcategory. Both of these plants achieved good removals of
toxic pollutants with organic removal averaging better than
203
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90% and completely eliminating phenolic compounds,
naphthalene, and xylene. The monitoring data for one of
these plants were used to develop performance standards for
ammonia-N, cyanide, phenols (4AAP), and toxic organic
pollutants for biological oxidation systems. These
standards are shown in Table VI-1 for those toxic pollutants
found in the steel industry wastewaters above treatability
levels.
Advantages and Limitations
The activated sludge system achieves significant reductions
of most toxic organic pollutants at significantly less
capital and operating costs than for carbon adsorption.
Also, consistent efflut-nt quality can be maintained if
sufficient pretreatment is practiced and shock loadings of
specific pollutants are eliminated. The temperature, pH and
oxygen levels in the system must be maintained within
certain ranges or fluctuating removal efficiencies of some
pollutants will occur.
Operational Factors
a. Reliability: Thj.s system is very reliable with proper
pretreatment and proper operation and maintenance.
b. Maintainability: As long as adequate pretreatment is
practiced, high effluent quality can be maintained. If
the system is upset, the operation can be brought under
control by seeding with biological floe or POTW
sludges.
Demonstration Status
Activated sludge systems are well demonstrated in the steel
industry. Biological oxidation systems are installed at
eighteen cokemaking operations.
Advanced Technologies
The Agency considered other advanced treatment technologies as
possible alternative treatment systems. Ion exchange and reverse
osmosis were considered because of their treatment effectiveness
and because, in certain applications, they allow the recovery of
certain process material.
1. Ion Exchange
Ion exchange is a process in which ions, held by
electrostatic forces to charged functional groups on the
surface of the ion exchange resin, are exchanged for ions of
similar charge from the solution in which the resin is
immersed. This is classified as an absorption process
204
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because the exchange occurs on the surface of the resin, and
the exchanging ion must undergo a phase transfer from
solution phase to solid phase. Thus, ionic contaminants in
a wastewater can be exchanged for the harmless ions of the
resin.
Low exchange systems used to treat wastewaters are always
proceeded by filters to remove suspended matter which could
foul the low exchange resin. The wastewater then passes
through a cation exchanger which contains tjhe ion exchange
resin. The exchanger retains metallic impurities such as
copper, iron, and trivalent chromium. The wastewater is
then passed through the anion exchanger which has a
different resin. Hexavalent chromium, for example, is
retained in this stage. If the wastewater is not
effectively treated in one pass through it may be passed
through another series of exchangers. Many ion exchange
systems are equipped with more than one set of exchangers
for this reason.
The other major portion of the ion exchange process is the
regeneration of the resin, which holds impurities removed
from the wastewater. Metal ions such as nickel are removed
by an acid cation exchange resin, which is regenerated with
hydrochloric or sulfuric acid, replacing the metal ion with
one or more hydrogen ions. Anions such as dichromate are
removed by a basic anion exchange resin, which is
regenerated with sodium hydroxide, replacing the anion with
one or more hydroxyl ions. The three principal methods used
by industry for regenerating the spent resins are:
a. Replacement Service: A regeneration service replaces
the spent resin with regenerated resin, and regenerates
the spent resin at itc own facility. The service then
treats and disposes of the spent regenerant.
b. In-Place Regeneration: Some establishments may find it
less expensive to conduct on-site regeneration. The
spent resin column is shut down for perhaps an hour,
and the spent resin is regenerated. This results in
one or more waste streams which must be treated in an
appropriate manner. Regeneration is performed as the
resins require it, usually every few months.
c. Cyclic Regeneration: In this process, the regeneration
of the spent .resins takes place within the ion exchange
unit itself in alternating cycles with the ion removal
process. A regeneration permits operation with a very
small quantity of resin and with fairly concentrated
solutions, resulting in a very compact system. Again,
this process varies according to application, but the
regeneration cycle generally begins with caustic being
pumped through the anion exchanger, which carries out
205
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hexavalent chromium, for example, as sodium dichromate.
The sodium dichromate stream then passes through a
cation exchanger, converting the sodium dichromate to
chromic acid. After being concentrated by evaporation
or other means, the chromic acid can be returned to the
process line. Meanwhile, the cation exchanger is
regenerated with sulfuric acid, resulting in a waste
acid stream containing the metallic impurities removed
earlier. Flushing the exchangers with water completes
the cycle. Thus, the wastewater is purified and, in
this example, chromic acid is recovered. The ion
exchangers, with newly regenerated resin, then enter
the ion removal cycle again.
Application and Performance
The list of pollutants for which the ion exchange system has
proven effective includes, among others, aluminum, arsenic,
cadmium, chromium (hexavalent and trivalent), copper,
cyanide, gold, iron, lead, manganese, nickel, selenium,
silver, tin, and zinc. Thus, it can be applied at a wide
variety of industrial concerns. Because of the heavy
concentrations of metals in metal finishing wastewaters, ion
exchange is used extensively in that industry. As an
end-of-pipe treatment, ion exchange is certainly feasible,
but its greatest value is in recovery applications. It is
commonly used as an integrated treatment to recover rinse
water and process chemicals. At some electroplating
facilities ion exchange is used to concentrate and purify
plating baths.
Ion exchange is highly efficient at recovering metal bearing
solutions. Recovery of chromium, nickel, phosphate
solutions, and sulfuric acid from anodizing is commercially
viable. A chromic acid recovery efficiency of 99.5 percent
has been demonstrated. Ion exchange systems are reported to
be installed at three pickling operations, however, none of
these systems were sampled during this study. Data for two
plants in the coil coating category are shown below.
206 \
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Ion Exchange Performance
Pollutant
All Values
mg/1
Al
Cd
Cr*»
Cr*«
Cu
CN
Au
Fe
Pb
Mn
Ni
Ag
S04
Sn
Zn
Plant
Prior to
Purifi-
cation
5.6
5.7
3.1
7.1
4.5
9.8
—
7.4
-
4.4
6.2
1.5
-
1.7
14.8
A
After
Purifi-
cation
0.20
0.00
0.01
0.01
0.09
0.04
-
0.01
_
0.00
0.00
0.00
-
0.00
0.40
Plant B
Prior to After
Purifi- Purifi-
cation cation
43.0
3.40
2.30
1.70
60
10
210.00
1.10
0.10
0.09
0.10
0.01
0.01
0.01
2.00
0.10
Advantages and Limitations
Ion exchange is a versatile technology applicable to a great
many situations. This flexibility, along with its compact
exchange an effective
However, the resins in
limiting factor. The
generally placed in the
its use in certain
nature and performance, makes ion
method of wastewater treatment.
these systems can prove to be a
thermal limits of the anion resins
vicinity of 60°C, could prevent
situations. Similarly, nitric acid, chromic acid, and
hydrogen peroxide can all damage the resins as will iron,
manganese, and copper when present with sufficient
concentrations of dissolved oxygen. Removal of a particular
trace contaminant may be uneconomical because of the
presence of other ionic species that are preferentially
removed. The regeneration of the resins presents its own
problems. The cost of the regenerative chemicals can be
high. In addition, the wastewater streams originating from
the regeneration process are extremely high in pollutant
cncentrations, although low in volume. These must be
further processed for proper disposal.
Operational Factors
a. Reliability: With the exception of occasional clogging
or fouling of the resins, ion exchange is a highly
dependable technology.
207
ii
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b. Maintainability: Only the normal maintenance of pumps,
valves, piping and other hardware used in the
regeneration process is usually encountered.
Demonstration Status
All of the applications mentioned in this section are
available for commercial use, and industry sources estimate
the number of units currently in the field at well over 120.
The research and development in ion exchange is focusing on
improving the quality and efficiency of the resins, rather
than new applications. Ion exchange is used in at least
three different plants in the steel industry. Also, ion
exchange is used in a variety of other metal finishing
operations.
2. Reverse Osmosis
Reverse osmosis (RO) is an operation in which pressure is
applied to a solution on the outside of a semi-permeable
membrane causing a permeate to diffuse through the membrane
leaving behind concentrated higher molecular weight
compounds. The concentrate can be further treated or
returned to the original operatiDn for continued use, while
the permeate water can be recycled for use as clean water.
There are three basic configurations used in commercially
available RO modules: tubular, sprial-wound, and hollow
fiber. All of these operate on the principle described
above, the major difference being their mechanical and
structural design characteristics.
The tubular membrane module has a porous tube with a
cellulose acetate membrane-lining. A common tubular module
consists of a length of 2.5 cm (1 inch) diameter tube wound
on a supporting spool and encased in a plastic shroud. Feed
water is driven into the tube under pressures varying from
40-55 atm (600-800 psi). The permeate passes through the
walls of the tube and is collected in a manifold while the
concentrate is drained off at the end of the tube. A less
widely used tubular RO module has a straight tube contained
in a housing, and is operated under the same conditions.
Spiral-wound membranes consist of a porous backing
sandwiched between two cellulose acetate membrane sheets and
bonded along three edges. The fourth edge of the composite
sheet is attached to a large permeate collector tube. A
spacer screen is then placed on top of the membrane sandwich
and the entire stack is rolled around the centrally locateu
tubular permeate collector. The rolled up package is
inserted into a pipe able to withstand the high operating
pressures employed in this process, up to 55 atm (800 psi).
When the system is operating, the pressurized product water
-------
permeates the membrane and flows through the backing
material to the central collector tube. The concentrate is
drained off at the end of the container pipe and can be
reprocessed or sent to further treatment facilities.
The hollow fiber membrane configuration is made up of a
bundle of poly amide fibers of approximately 0.0075 cm (0.003
in.) OD and 0.0043 cm (0.0017 in.) ID. A commonly used
hollow fiber module contains several hundred thousand of the
fibers placed in a long tube, wrapped around a flow screen,
and rolled into a spiral. The fibers are bent in a U-shape
and their ends are supported by an epoxy bond. The hollow
fiber unit is operated under 27 atm (400 psi), the feed
water being dispersed from the center of the module through
a porous distributor tube. The permeate flows through the
membrane to the hollow interiors of the fibers and is
collected at the ends of the fibers.
The hollow fiber and spiral-wound modules have a distinct
advantage over the tubular system in that they contain a
very large membrane surface area in a relatively small
volume. However, these membranes types are much more
susceptible to fouling than the tubular system, which has a
larger flow channel. This characteristic also makes the
tubular membrane easier to clean and regenerate than either
the spiral-wound or hollow fiber modules.
Application and Performance
At a number of metal processing plants, the overflow from
the first rinse in a countercurrent setup is directed to a
reverse osmosis unit, where it is separated into two
streams. The concentrated stream contains dragged out
chemicals and is returned to the bath to replace the loss of
solution due to evaporation and dragout. The dilute stream
(the permeate) is routed to the last rinse tank to provide
water for the rinsing operation. The rinse flows from the
last tank to the first tank and the cycle is complete.
The closed-loop system described above may be supplemented
by the addition of a vacuum evaporator after the RO unit in
order to further reduce the volume of reverse osmosis
concentrate. The evaporated vapor can be condensed and
returned to the last rinse tank or sent on for further
treatment.
The largest application of reverse osmosis systems is
the recovery of nickel and other metal solutions. It has
been shown that RO can generally be applied to most acid
metal baths with a high degree of performance, providing
that the membrane unit is not overtaxed. The limitations
most critical are the allowable pH range and maximum
operating pressure for each particular configuration.
209
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Adequate prefiltration is also essential. Only three
membrane types are readily available in commercial RO units.
For the purpose of calculating performance predictions of
this technology, a rejection rate of 98 percent was assumed
for dissolved salts, with 95 percent permeate recovery.
Advantages and Limitations
The major advantage of reverse osmosis for treating
wastewaters is the ability to concentrate dilute solutions
for recovery of salts and chemicals with low power
requirements. No latent heat of vaporization or fusion is
required for effecting separations; the main energy
requirement is for a high pressure pump. RO requires
relatively little floor space for compact, high capactiy
units, and exhibits high recovery and rejection rates for a
number of typical process solutions. A limitation of the j
reverse osmosis process is the limited temperature range for •-
satisfactory operation. For cellulose acetate systems, the
preferred limits are 18 to 30°C (65 to 85°F); higher
temperatures will increase the rate of membrane hydrolysis
and reduce system life, while lower temperatures will result
in decreased fluxes with no damage to the membrane. Another
limitation is the Inability to handle certain solutions.
Strong oxidizing agents, strong acidic or basic solutions,
solvents, and other organic compounds can cause dissolution
of the membrane. Poor rejection of some compounds such as
borates and low molecular weight organics is another
problem. Fouling of membranes by failures, and fouling of
membranes by wastewaters with high levels of suspended
solids can be a problem. A final limitation is the
inability to treat or achieve high concentration with some
solutions. Some concentrated solutions may have initial
osmotic pressures which are so high that they either exceed
available operating pressures or are uneconomical to treat.
Operational Factors
a. Reliability: RO systems are reliable provided the
proper precautions are taken to minimize the chances of
fouling or degrading the membrane. Sufficient testing
of the wastewater stream prior to application of an RO
system will provide the information needed to insure a
successful application.
b. Maintainability: Membrane life is estimated to fall
between 6 months and 3 years, depending upon the use of
the system. Down time for flushing or cleaning is on
the order of two hours as often as once each week; a
substantial portion of maintenance time must be spent
on cleaning any prefilters installed ahead of the
reverse osmosis unit.
210
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Demonstration Status
There are presently at least one hundred reverse osmosis
wastewater applications in a variety of industries. In
addition to these, thirty to forty units are used to provide
pure process water for several industries. Despite the many
types and configurations of membranes, only the spiral-wound
cellulose acetate membrane has had widespread success in
commercial applications. There are no known RO units
presently in operation in the steel 'industry to treat
wastewaters.
Zero Discharge Technologies
Zero discharge of process wastewater is achieved in several
subcategories of the steel industry. The most commmonly used
method is to treat the wastewater sufficiently so it can be
completely reused in the originating process or to control water
application in semi-wet air pollution control systems so that no
discharge results. This method is used principally in
steelmaking.
Another potential means to achieve zero discharge is by the use
of evaporation technology. Evaporation systems concentrate the
wastewater constituents and produce a distillate quality water
that can be recycled to the process. Although this technology is
very costly and energy intensive, it may be the only method
available to attain zero discharge in many steel industry
subcategories.
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 evaporation is used in this report
to describe both processes. Both atmospheric and vacuum
evaporation are commonly used in industry today. Atmospheric
evaporation could be accomplished simply by boiling the liquid.
However, to aid evaporation, heated liquid is sprayed on an
evaporation surface, and air is blowr, over the surface and
subsequently released to the atmosphere. Thus, evaporation
occurs by humidification of the air stream, similar to a drying
process. Equipment for carrying out atmospheric evaporation is
quite similar for most applications. The major element is
generally a packed column with an accumulator bottom.
Accumulated wastewater is pumped from the base of the column,
through a heat exchanger, and back into the top of the column,
where it is sprayed into the packing. At the same time, air
drawn upward through the packing by a fan is heated as it
contacts the hot liquid. The liquid partially vaporizes and
211
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humidifies the air stream. The fan then blows the hot, humid air
to the outside atmosphere.
Another form of atmospheric evaporator also works on the air
humidification principle, but the evaporated water is recovered
for reuse by condensation. These air humidification techniques
operate well below the boiling point of water and can use waste
process heat to supply some of the energy required.
In vacuum evaporation, the evaporation pressure is lowered to
cause the liquid to boil at reduced temperature. All of the
water vapor is condensed and, to maintain the vacuum condition,
noncondensible gases (air in particular) are removed by a vacuum
pump. Vacuum evaporation may be either single or double effect.
In double effect evaporation, two evaporators are used, and the
water vapor from the first evaporator (which may be heated by
steam) is used to supply heat to the second evaporator. As it
supplies heat, the water vapor from the first evaporator
condenses. Approximately equal quantities of wastewater are
evaporated in each unit; thus, the double effect system
evaporates twice the amount of water that a single effect system
does, at nearly the same energy cost. The double effect
technique is therB«odynamically possible because the second
evaporator is maintained at Icwer pressure (high 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 sumberged 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
ejector-type pump, which creates the required vacuum by the flow
of the condenser cooling water through a venturi. Wastewater
accumulates in the bottom of the vessel, and 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 also removed from the bottom of the vessel.
The major elements of the climbing film evaporator are the
evaporator, separator, condenser, and vacuum pump. Wastewater is
"drawn" into the system by the vacuum so that a constant liquid
level is maintained in the separator. Liquid enters the
steam-jacketed evaporator tubes, and part of it evaporates sov
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
212
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down through the condenser tubes. The condensate, along with any
entrained air, is pumped out of the bottom of the condenser by a
liquid ring vacuum pump. The liquid seal provided by the
condensate keeps the vacuum in the system from being broken.
Application and Performance
Both atmospheric and vacuum evaporation are used in many
industrial plants, mainly for the concentration and recovery of
process solutions. Many of these evaporators also recover water
for rinsing. Evaporation has also been used to recover phosphate
metal cleaning solutions.
Advantages and Limitations
Advantages of the evaporation process are that it permits
recovery of a wide variety of process chemicals, and it is
applicable for concentration or removal of compounds which cannot
be accomplished by other means. The major disadvantage is that
the evaporation process consumes relatively large amounts of
energy. 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 suspended 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 precipitate deposition. In addition,
low temperature differences in the evaporator will eliminate
nucleate boiling and supersaturation effects. Steam distillable
impurities in the process stream are carried over with the
product water and must be handled by pre or post-treatment.
Operational Factors
1. Reliability: Proper maintenance will ensure a high degree
of reliability for the system. Wthout such attention, rapid
fouling or deterioration of vacuum seals may occur,
especially when handling corrosive liquids.
2. 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.
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Demonstration Status
Evaporation is a fully developed, commercially available
wastewater treatment technology. 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. Evaporation technology is not used in steel industry
applications for wastewater treatment.
C. In-Plant Controls and Process Modifications
In-plant technology is used in the steel industry to reduce or
eliminate the pollutant load requiring end-of-pipe treatment and
thereby improve the efficiency of existing wastewater treatment
systems or to reduce the requirements of new treatment
facilities. In-plant technologies demonstrated in the steel
industry includes alternate rinsing procedures, water
conservation, reduction of dragout, automatic controls, good
housekeeping practices, recycle of untreated process waters and
process modifications.
1. In-Process Treatment and Controls
In-process treatment and controls apply to both existing and
new installations and include existing technologies and
operating practices. The data received from the industry
indicates that water conservation practices are widely used
in many subcategories. Within any particular subcategory
process wastewater can vary substantially. In many cases,
these variations are directly related to in-process water
conservation and control measures. Although the effluent
limitations and standards do not regulate flow, they are
based upon model flow rates demonstrated in the respective
subcategories.
While effective control ovsr operating practices is one
method of in-plant control, others are more complex and
require greater expenditures of capital. One of these is
the installation of cascade rinsing (counter-current)
rinsing systems. Cascade rinsing is a demonstrated
in-process control for pickling and hot coating operations
and may be implemented at other processes that use
conventional rinsing techniques.
Another in-process control is the recycle of process water.
In several steel industry processes, wastewaters are
recycled "in- plant" even prior to treatment. For example,
in the cold rolling process, oil emulsions can be collected
and returned to the mill in recirculation systems thereby
reducing the volumes of wastewater discharged. This control
method may not necessarily be used in all processes because
of the product quality or recycle system problems that may
be encountered.
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Other simple in-process controls that can affect discharge
quality include good housekeeping practices and automatic
equipment. For example, if tight control over the process
is maintained and spills are controlled, excessive "dumps"
of waste solutions can be averted. Also, automatic controls
can be installed that control applied water rates to insure
that water is applied only when a mill is actually
operating. For mills or lines that are not operated
continuously the volume of watar that can be conserved with
this practice can be significant.
2. Process Substitutions
There are several instances in the steel industry where
process substitutions can be used to effectively control
wastewater discharges. One is a cold rolling operations
where mills can be designed to operate either in a
once-through or recycle mode. If those mills with
once-through systems operated in a recycle mode, oil usage
would be reduced and savings could be achieved since a
smaller treatment system would be required.
Another area where in-process substitutions can achieve
significant reductions in wastewater flows and pollutant
loads is by selecting dry air pollution control systems over
wet systems.
•» *.
L
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TABLE VI-1
TOXIC ORGANIC CONCENTRATIONS
ACHIEVABLE BY TREATMENT
Achievable Concentration(pg/l)
No. Priority Pollutant
003 Acryl emit rile
004 Benzene
009 Rexachlorobencene
011 1,1,1-Trichloroethane
021 2,4,6-Trichlorophenol
022 Parachlorometacretol
023 Chloroform
024 2-Chlorophenol
034 2,4-Dimethylphenol
035 2,4-Dinitrotoluene
036 2,6-Dinitrotoluene
038 Ethylbenzene
039 Fluoranthene
054 Isophorone
055 Naphthalene
057 2-Nitrophenol
060 4,6-Dinitro-o-cre«ol
064 Pentachlorophenol
065 Phenol
066-071 Phthalatet, Total
072 Benzo(a)anthracene
073 Ben£o(a)pyrene
076 Chrysene
077 Acenaphthylene
078 Anthracene
080 Fluorene
084 Pyrene
085 Tetrachlorethylene
086 Toluene
130 Xylene
Carbon Adaorption
200
50
1
100
25
50
20
50
25
50
50
50
10
50
25
25
25
50
50
100
10
1
5
10
1
10
10
50
50
10
Biological Oxidation
100
50
*
*
50
*
200
50
5
50
100
25
5
noo
5
100
25
*
25
200
5
5
10
10
1
5
10
100
50
100
(1)
* No significant removal over influent level.
(1) Two-stage activated aludge lyatem.
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VOLUME I
SECTION VII
DEVELOPMENT OF COST ESTIMATES
Introduction
This section reviews the Agency's methodology for'developing cost
estimates for the alternative water pollution control systems
considered for each subcategory. The economic impacts due to these
costs and to other factors affecting the steel industry are reviewed
in the above references report.
Basis of Cost Estimates
Costs developed for. the various levels of treatment (i.e., 3PT, BAT,
NSPS and Pretreatment) are presented in detail in each subcategory
report of the Development Document. Model costs include investment,
capital depreciation, land rental interest, operating and maintenance,
and energy. The costs for BPT and BAT are summarized and presented in
Sections VIII and IX of this report. Costs for PSES are presented in
Section XII. Only model costs are presented for NSPS and PSNS while
total industry costs are presented for the other levels of control.
The Agency did not include estimates of capacity addition in this
report. However, estimates of capacity additions, retirements, and
reworks are included in Economic Analysis of Effluent Guidelines -
Integrated Iron and Steel Industry.
The Agency developed model wastewater treatment systems and cost
estimates for those systems. Industry-wide costs to comply with this
regulation were determined from application of the costs for the
selected model treatment systems to each plant taking into account
treatment in place as of a reference date. For each subcategory, the
model costs were developed as follows:
1. National annual production and capacity data for each subdivision
or segment along with the number of plants in each subdivision
were determined. From these data, an "average" plant size was
established for each subdivision.
2. For finishing operations, where more than one mill or line of the
same operation exists at one plant site, the capacities of these
mills or lines were summed to develop a site size and costs for
one wastewater treatment facility were developed as noted below.
This manner of sizing model plants more accurately represents
actual wastewater treatment practices in the industry.
Wastewaters from all cold mills at a given site are usually
treated in central treatment systems. By using site sizes, where
appropriate, wastewater treatment within subcategories was more
accurately reflected in the cost estimates.
217
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S. If different product types or steel types within a subcategory
were found to have different average sizes, separate cost models
were developed to more accurately define the costs for these
groupings.
4. Applied model process flow rates were established based upon data
obtained from questionnaires and accumulated during field
sampling visits. The model flows are expressed in 1/kkg or
gal/ton of product.
5. A treatment process model and flow diagram was developed for each
subcategory based upon appropriate subcategory treatment systems
and effluent flow rates representative of the application of
established water pollution control practices.
6. Finally, a detailed cost estimate was made on the basis of each
alternative treatment system. All cost estimated were developed
in July 1978 dollars.
Total annual costs were developed by summing the operating costs
(including those for chemicals, maintenance, labor, and energy) and
capital recovery costs. Capital recovery costs were calculated using
a capital recovery factor (CRF) derived specifically for the steel
industry. Separate CRF's were derived for capital investments and for
land costs. An explanation of the derivation of these factors is
provided below.
The purpose of a capital recovery factor is to annualize capital
investment costs over the useful life of an asset. Annualizing
capital investment costs using a capital recovery factor procedure
should be distinguished from using a depreciation schedule to
calculate depreciation expense for accounting purposes. The purpose
of a depreciation schedule is to match the historic cost or book value
of an investment with accounting revenues occurring over the useful
life of the asset. A capital recovery factor indicates the magnitude
of a series of periodic cash flows which, over the useful life of the
asset, will have a discounted present value equal to the discounted
present value of the investment. The discounted present value of an
investment is generally not the same as its book value due to the
impact of investment tax credits, tax-deductible non-cash expenses
such as depreciation, and tax-deductible investment-related expenses
such as interest and property taxes.
Assumption Underlying Capital Recovery Factors
For purposes of this study, it was assumed that pollution control
capital expenditures would be financed 20 percent by non-tax exempt
corporate debt and 80 percent by tax-exempt industrial revenue bonds.
The interest rate on the corporate debt was determined by adding a
premium of 2.7 percent to the inflation rate assumed for the period
1981-1982. The tax-exempt interest rate was assumed to be two-thirds
of the non-exempt interest rate. A marginal income tax rate of 50.1
percent was assumed, based on a marginal federal rate of 46 percent
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and a tax-deductible average state tax rate of 7.55 percent. An
investment tax credit of 10 percent and the five-year "capital
recovery" tax depreciation factors were assumed to apply to
investments in pollution control equipment associated with steel mill
equipment. A property tax rate of 2.38 percent of net book value was
also assumed, based on 14-year straightline depreciation for book §
purposes. • I
I
The capital recovery factor used by the Agency in this report is
different from and more appropriate than that used in the Lecember
1980 Development Document. This formula is more appropriate as it
accounts for the tax effects of the industry's investment in capital.
Calculation of Capital Recovery Factors
Given the assumption listed above, the Q.4 percent inflation rate
projection for 1981 implies a weighted average interest rate on
pollution control debt of 8.91 percent:
(9.4 + 2.7)* .2 + .67*(9.4 + 2.7)* .8 « 8.91%
Using the discount rate to calculate the present value of a $1.0
million investment in pollution control equipment yields an estimated
present value of -$351,020. Annualizing this outlay over a 14-year
period at the assumed rate of interest results in a level annual
payment of $44,854 after taxes, which implies an outlay of $89,889
before taxes. Normalizing the before-tax outlay by the initial
investment of $1.0 million results in the capital recovery factor for
pollution control equipment of 0.0899.
The calculation of an annualized charge for land is slightly diferent
because land does not qualify for an investment tax credit and is not
a depreciable wasting asset. Instead, land investments are
characterized by capital appreciation which is recovered at the and of
the investment period. For purposes of this study, the Agency assumed
that property taxes would be based on an assessed value rising at the
average rate of inflation over the period, and that a recovery or
reversion of the appreciated land would occur at the end of the
14-year period. Based upon this assumption, a $1.0 million investment
in land financed at the weighted average interest rate used for
pollution control equipment would have a present value of -$247,340.
Recovery of this cost over a 14-year period would require receiving an
annual rent after-tax of $31,660 per year. This corresponds to a
before-tax imputed rental of $63,340. Normalizing this imputed rental
by the initial investment of $1.0 million yields the required capital
recovery factor for land of 0.0634.
Basis for Direct Costs
Construction costs are highly variable and in order to determine these
costs in a consistent manner, the following parameters were
established as the basis of estimates. The cost estimates reflect
average costs. .
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N
! 1. The treatment facilities are contained within a "battery limit
| site location and are erected on a "green field" site. Site
j clearance costs have been estimated based upon average site
| conditions with no allowances for equipment relocation.
] Equipment relocation costs could not be included because
1 equipment relocation is highly site specific and in fact not
i required at most facilities.
2. Equipment costs for most components are based upon specific
effluent water rates and pollutant loads. A change in water flow
rates will affect costs. For vacuum filters, costs are based on
the square feet (ft2) of surface area of the filter which is a
function of the amount of solid waste to be dewatered. Costs for
rinse reduction technology (i.e., cascade rinse) is based upon
production capacity. For these two components, costs are
affected more by these variables than by flow.
3. The treatment facilities are assumed to be located in reasonable
proximity to the wastewater source. Piping and other utility
costs for interconnecting utility runs from the production
facility to the battery limits of the treatment facility are
based upon a linear distance estimate of 2500 feet. TI.e Agency
considers 2500 ft to be generous for most applications. The cost
of return piping is included in recycle system costs.
4. Land acquisition costs are included in the cost estimates
prepared for this study. An average land cost of $38,000/acre
(1978 dollars) is used to estimate land cost requirements for the
model treatment components. Total land costs were then adjusted
to represent an annual charge to be incurred over the life or the
treatment system by applying the land cost capital recovery
factor explained above.
5. Costs for all nessary instrumentation to operate the model
wastewater treatment facilities have been included in the
Agency's cost estimates, including pH and ORP control, flow
meters, level controls, and various vacuum instruments, as
appropriate.
6.. The Agency's cost estimates include costs for standard safety
items including fencing, walkways, guard rails, telephone
service, showers, and lighting.
7. The Agency's cost estimates are based upon delivered prices of
the water pollution control equipment and related items, thus
freight charges are included in the Agency's cost estimates. i
However, because of the highly variable nature of sales and use j
taxes imposed by state, regional, country, and local governments, 1
the Agency did not include such taxes in its cost estimates. • {
I
8. Control and treatment system buildings are prefabricated !
buildings; not of brick or block construction. ]
220 j
i
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In general, the cost estimates reflect an on-site installed cost for a
treatment plant with electrical substation and equipment for powering
the facilities, all necessary pumps, essential controls and
instrumentations, treatment plant interconnecting feed pipe lines,
chemical feed and treatment facilities, foundations, structural steel,
and a control house. Access roadways within battery limits are
included in estimates based upon 3.65 cm (1.5 inch) thick bituminous
wearing course and 10 cm (4 inch) thick sub-base with sealer, binder,
and gravel surfacing. A nine gauge chain link fence with three strand
barb wire and one truck gate were included for fencing. The cost
estimates also include a 15% contingency fee, 10% contractor's
overhead and profit allowance, and engineering fees of 15%.
Sources of cost data for wastewater treatment system components and
other direct cost items include vendor quotations and cost manuals
commonly used for estimating construction costs. These manuals
include:
b -
The Richardson Rapid System, Process Plant
Estimating Standards; 1978-1979 Edition;
Engineering Services, Inc.
Building Construction Cost Data; 1978; Robert
Company, Inc.
Contruction
Richardson
Snow Means
Basis for Indirect Costs
In addition to developing estimates for individual treatment
components, the Agency has also included indirect costs in its total
cost estimates for water pollution control equipment. Indirert costs
cover such items as engineering expenses, taxes and insurance,
contractor's fees and overheads and other miscellaneous expenses.
Normally, these indirect costs are represented by three broad expense
categories: engineering, overhead and profit, and contingencies.
Cost manuals, vendor quotes and actual installation costs generally
show a range for total indirect costs of between 15% and 40% of total
direct costs The Agency's estimates contain indirect cost factors
which total 45% of the total direct costs. The factors used by the
Agency and an example of how they are applied to direct costs are
shown below:
Incremental
Cost.5 ($)
Total Cost ($)
Total Direct Cost
Contingency a> 15%
Overhead and Profit a> 10%
Engineering 3) 15%
Total Indirect Costs
1,OOC,000 1,000,000
150,000 1,150,000
115,000 1,265,100
189,750 1,454,750
454,750 (45.5% of direct costs)
Cost comparisons made between the Agency's estimates and actual
installation costs have demonstrated that the Agency's methodology,
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including its method of applying indirect costs, is proper and can be
used to accurately estimate industry-wide costs.
BPT, BAT. NSPS, PSES and PSNS Cost Estimates
Two cost estimates were made for this study for the BPT, BAT and PSES
levels of treatment. The first deals with the capital costs for the
systems already installed and the second accounts for the capital
costs for the treatment components still required at each of these
levels. Additionally, both in-place and required annual costs were
calculated and these costs are included in all cost summaries
presented in this document.
Because DCP responses were received from all major steel operations
and almost all minor steel facilities, the data base on installed
treatment components (as of January 1, 1978)^ was fairly complete.
Additionally, the Agency updated the information to July 1, 1981,
based upon personal knowledge of EPA Staff, NPDES records, and conjtact
with the industry during the. public comment period on the proposed
regulation. Using this data base, a plant-by-plant inventory was
completed which tabulated the treatment components presently installed
and those components which are required to bring the systems up to the
BPT, BAT and PSES treatment levels. Hence, an estimate of capital
cost requirements was made for each plant and subcategory by scaling
individual plants to the developed treatment model and factoring costs
based upon production by the "six-tenth factor". By this method, the
Agency estimated the expenditures already made by the steel industry.
These data were summarized earlier in Section II and are also
summarized in' each subcategory report.
For NSPS and PSNS, total industry costs have not been presented in
this report since predictions of future expansion in the industry were
not made as part of this study.
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VOLUME I
SECTION VIII
EFFLUENT QUALITY ATTAINABLE
THROUGH THE APPLICATION OF THE BEST PRACTICABLE
CONTROL TECHNOLOGY CURRENTLY AVAILABLE
Introduction
Best Practicable Control Technology Currently Available (BPT) is
generally based upon the average of the best existing performances at
plants of various sizes, ages, and unit processes within the
industrial subcategory. This average is not based upon a broad range
of mills within the subcategory, but is based upon performance levels
achieved at plants known to be equipped with the best wastewater
treatment facilities.
The Agency also considered the following factors:
1. Tho size and age of equipment and facilities involved.
2. The processes employed.
3. Non-water quality environmental impacts (including sludge
generation and energy requirements).
4. The engineering-aspects of the applications of various types of
control techniques.
5. Process changes.
6. The total cost of application of technology in relation to the
effluent reduction benefits to be achieved from such application.
BPT emphasizes treatment facilities at the end of a manufacturing
process but can also include control technologies within the process
itself when they are considered to be normal practice within the
industry.
The Agency also considered the degree of economic and engineering
reliability in order to determine whether a technology is "currently
available." As a result of demonstrations, projects, pilot plants and
general use, the Agency must have a high degree of confidence in the
engineering and economic practicability of the technology at th< time
of commencement of construction or installation of the c^.itrol
facilities.
223
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Identification of BPT
For the most part, the proposed BPT limitations are the same as those
contained in prior steel industry water pollution control regulations.
The Agency proposed less stringent limitations where the prior
limitations were not being achieved in the industry, or more recent
and complete data indicated the prior limitations were not appropriate
because of changes in subcategorization or the absence of specific
limited pollutants in the respective wastewaters.
The major changes between the proposed BPT limitations
contained in the prior regulation are summarized below:
and those
Subcategory
A. Cokemaking
B. Sintering
D. Steelmaking
H. Scale Removal
I. Acid Pickling
J. Cold Rolling
Change; Prior Regulations co Proposed Regulation
The suspended solids limitation for coke-
making operations was increased.
All of the limitations for sintering opera-
tions were increased based upon increased
model treatment system flow rates.
Segments were added for BOF wet-suppressed
combustion operations.
For scale removal operations, the dissolved
chromium limitations were changed to total
chromium limitations; and, for Kolene®
operations, the cyanide limitations were
deleted.
For combination acid pickling operations,
limitations for dissolved chromium and nickel
were changed to total chromium and total
nickel.
Separate zero discharge limitations for cold
worked pipe and tube operations were proposed.
These operations had been included in the
subdivision for hot worked pipe and tube
operations in prior regulations.
K. Alkaline Cleaning
L. Hot Coating
Limitations for dissolved iron, dissolved
chromium, and dissolved nickel were deleted
for alkaline cleaning operations.
Separr-te limitations were proposed for
galvai izing hot coating operations of wire
products and fasteners and all hot coating
operations using metals other than zinc and
terne metal. These operations were not
regulated separately in the prior regulation.
224
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Other than the changes noted above, the Agency proposed the same BPT
limitations that were contained in the prior regulations, even though
in many instances, more stringent limitations might be justified. The
Agency chose this course of action for the following reasons:
1. The technological bases of the prior regulations were upheld
by the Court in A IS I-1 and AISI-II and the- Agency believes f|
the limitations and standards are appropriate. ||
«l
2. For virtually every subcategory, the Agency proposed BAT and ,|?
BCT limitations more stringent than the proposed BPT .fss
limitations. Thus, upon promulgation, the BAT and BCT
limitations would become the operative limitations for NPDES
permits and, in most cases, the BPT limitations would have
little or no impact on the permitting process.
Based upon comments received on the proposed regulation, the Agency
has made some substantial changes to the BPT limitations from tnose
that were proposed, particularly for the forming and finishing
operations. In some cases, more stringent BPT limitations were
promulgated. In other cases, leas stringent BPT limitations were
promulgated. For the basic steelmaking operations, most of the
proposed BPT limitations were promulgated. In all cases, however, the
Agency used the same basic model treatment technologies to develop the
proposed BPT limitations as were used to develop the final BPT
limitations.
The public comments caused the Agency to re-examine the subdivision of
each subcategory, in terms of whether or not model treatment system
flows based upon product type or operating mode are appropriate,
whether or not in-process of end-of-pipe flow reduction systems are
appropriate, and, the performance of the model treatment systems in
achieving the desired effluent quality. For the basic steelmaking
operations, the response to public comments did not cause the Agency
to substantially alter its conclusions regarding the appropriateness
of the proposed BAY limitations. Thus, upon promulgation of more .-,
stringent BAT limitations for these operations, the Agency saw no J
reason to alter the proposed BPT limitations except where public s
comments provided compelling evidence that they are too stringent. m
For many of the forming and finishing operations, the response to .«S
public comments caused the Agency to substantially alter the sf
subdivision of the subcategories, change model treatment system flow
rates and, reevaluate the performance of the model treatment systems.
Also, the Agency found that substantial flow reduction systems
included in many of the BAT alternatives are not warranted. Thus, for
these operations, the Agency believes that revised BPT limitations are
appropriate. Alternatively, the Agency could have promulgated the
proposed BPT limitations and more stringent BAT limitations, but chose
not to do so because no additional technology would bs required to
achieve the more stringent BAT limitations; and, the Regulation would
be confusing and not in accordance with the Agency's policy of
co-treatment of compatible wastewaters.
-------
The Agency revised the BPT limitations for the forming and finishing
operations for the following reasons:
1. Based upon data and comments received on the proposed
regulation, the Agency decided not to promulgate more
stringent BAT limitations in several subcategories (Hot
Forming, Salt Bath Descaling (formerly Scale Removal), Cold
Rolling, Acid Pickling, Alkaline Cleaning, and part of Hot
Coating). Because additional wastewater treatment
technology beyond that used to develop the BPT limitations
would not be required, the Agency believes it is appropriate
to limit those toxic pollutants found in the wastewaters
from the respective subcategories at the BPT level.
2. In some cases, the Agency's response to comments involved a
complete reevaluation of the new and previously available
data for particular subcategories. For some operations, the
data demonstrate that the model treatment technologies
perform substantially better than indicated by data used to
develop the prior regulations (Hot Forming, Acid Pickling,
Hot Coating). In the absence of more stringent BAT
limitations for these operations, the Agency believes it is
appropriate that the BPT limitations are based upon these
data. For other operations, the Agency found the
subdivision of certain subcategories contained in the
proposed regulation is not appropriate (Salt Bath Descaling
(formerly Scale Removal), Acid Pickling, Cold Forming,
Alkaline Cleaning). Revised subdivision of these
subcategories based upon product-related process water
requirements or mode of operation was provided.
3. The selection of limited pollutants was modified in several
instances to facilitate co-treatment of compatible
wastewaters not possible with the proposed BPT limitations;
(Salt Bath Descaling (formerly Scale Removal), Acid
Pickling, Cold Rolliing, hot Coating).
The bases for all of these changes is set out in detail in the
subcategory reports presented in the development document. A summary
is provided below:
Subcategcry Change-Proposed Regulation to Final Regulation
A. Cokemaking The suspended solids limitations were
increased further based upon additional
data. A separate segment was provided
for merchant cokemaking operations.
B. Sintering All of the sintering limitations were
increased further based upon an increase
in the model treatment system flow rate.
D. Steelmaking The Open hearth Semi-Wet segment was deleted.
226
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Hot Forming
Less stringent limitations were promulgated
for BOF Wet-Open Combustion and Wet Electric
Arc Furnace operations based upon changes in
respective model treatment system flow rates.
The limitations for all hot forming operations
were revised to reflect actual performance
of the model treatment system.
H. Salt Bath Descaling The Salt Bath Descaling subcategory (formerly
Scale Removal) was subdivided differently to
take into account product-related process
water requirements and modes of operation
(batch and continuus). Performance data
submitted by the industry were used as a
basis for the limitations.
I. Acid Pickling
J. Cold Forming
k. Alkaline Cleaning
L. Hot Coating
The Acid Pickling subcategory was treated in
the same fashion as the Scale Removal
Subcategory. Fume scrubber operations
are limited separately on a daily mass basis
not related to production rate.
Separate limitations were promulgated for
Single Stand Recirculation and Direct
Application Cold Rolling Mills. Limitations
for two toxic organic pollutants were
promulgated for all cold rolling operations.
The Alkaline Cleaning subcategory has been
subdivided to take into account higher
process water requirements for both batch
and continuous operations.
Limitations for the Hot Coating subcate-
gory were made consistent with those for
acid pickling and cold rolling operations to
facilitate co-treatment.
Development of BPT Limitations
Model Treatment Systems
As noted above, the Agency used the same model treatment systems to
develop the promulgated BPT limitations as were used to develop the
prior and proposed BPT limitations. These technologies are installed
throughout the industry and are well demonstrated. The model
treatment systems are described in detail in the subcategory reports
of this development document.
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Model Treatment System Flow Rates
The Agency's approach to developing the BPT limitations based upon the
model treatment systems includes specification of a model treatment
system effluent flow rate and performance standards for the limited
pollutants. The model treatment system flow rates have either been
retained from the proposed or prior regulations; or, in several cases
revised based upon some of the factors noted above. The Agency has
established model treatment system effluent flow rates based upon the
best performing plants in each subcategory rather than upon averages
of all plants or upon statistically derived flows because, to a large
extent, flow rates are within the control of the operator.
For the basic steelmaking operations where recycle of air pollution
control system wastewaters or process wastewaters is an integral part
of the model treatment systems, the "average of the best" blowdown
rates or recycle rates formed the basis for the model treatment system
effluent flow rates used to develop the BPT limitations. The hot
forming operations were evaluated in much the same fashion in that the
primary scale pit recycle rates and thus the model treatment system
effluent flow rate for each subcategory were determined from the
average of the best or most appropriate recycle rates.
For the other finishing operations, the Agency used two approaches for
developing the model treatment system effluent flow rates. Production
weighted flow rates were developed by product for Salt Bath Descaling
and Acid Pickling operations. As noted above, the Agency
substantially revised the subdivision of these subcategories to take
into account product related rinsewater flow requirements. In doing
so, the Agency believes that production weighted flows are appropriate
because it could not develop discreet groups of the best plants in
each segment. Thus, the production weighted flow provides the best
measure of a model plant. For Cold Rolling, Alkaline Cleaning, and
Hot Coating operations, the average of the best discharge flows were
used to establish the model BPT effluent flow rates. The Agency
believes the "average of the best" flows for these operations are
appropriate because it could identify the best plants. In any event,
in all but a few cases, the production weighted average flow rates for
these operations are about the same as, or less than, the "average of
the best" flow rates.
The development of the respective model treatment system flow rates is
set out in detail in each subcategory report.
Model Treatment System Effluent Quality
The Agency used the model treatment system effluent flow rates and
performance standards for the limited pollutants to develop the BPT
limitations. The development of the performance standards for the
limited pollutants is presented in Appendix A. In several cases,
particularly in the forming and finishing operations, the Agency used
data from central treatment facilities that treat compatible
wastewaters to establish and demonstrate compliance with the BPT
228
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limitations. The Agency believes use of central treatment plant data
for these purposes is appropriate because it is consistent with the
manner in which the Agency structured the Regulation with respect to
co-treatment of compatible wastewaters and is consistent with current
treatment practices in the industry.
BPT Effluent Limitations
Table 1-2 summarizes the 1974 and 1976 BPT limitations, along with the
changes that have been made and the requirements of the promulgated
regulation. Where no changes are noted, the limi'tations are the same
as the original limitations. The guidelines are based on mass
limitations in kilograms per 1000 kilograms (lbs/1000 Ibs) except for
fume scrubbers at acid pickling and hot coating operations where the
limitations are in kg per day. As noted earlier, these mass
limitations do not require the attainment of any particular discharge
flow or effluent concentration. There are virtually an infinite
number of combinations of flow and concentration that can be used to
achieve the appropriate limitations. This is illustrated in Figure
VIII-1 which shows the BPT limitation for suspended solids for the
Blast Furnace subcategory. Also shown on this figure, are the
relative positions of the sampled plants, some of which are in
compliance and some of which did not achieve the limitations. As
shown by this diagram, those plants that do not presently achieve the
discharge limitation could do so by reducing either discharge flow or
effluent concentration, or a combination of the two.
Costs to Achieve the BPT Limitations
Based upon the cost estimates developed by the Agency, the
industry-wide investment costs to achieve full compliance with the BPT j
limitations is approximately $1.7 billion (in July 1, 1978 dollars).
The Agency estimates that as of July 1, 1981, about $0.21 billion of j
this amount remained to be spent by the industry. The total annual
cost associated with the BPT regulation is about $0.20 billion. A
breakdown of these BPT costs by subcategory is presented in Table
VIII-1. The Agency believes that the effluent reduction benefits j
resulting from compliance with the BPT limitations justify the !
associated costs. >
These costs are different than~ those presented in the Draft
Development Document. As noted earlier, the Agency updated the status
of the industry with respect to the installation of pollution control
facilities from January 1978 to July 1981. Also, the installed and
required costs for production facilities shut down during the mid to
late 1970's were deleted. These facilities were included in the data
base for the proposed regulation. The above estimates do not include
costs for treatment facilities installed by the industry which are not
required to achieve the BPT limitations or for facilities installed
which provide treatment more stringent than required to achieve the
BPT and BAT limitations (e.g. cascade rinse and acid recovery systems
for acid pickling operations; high rate recycle for hot forming
operations). ;
229
I
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TABLE VIII-1
BPT COST SUMMARY
IROH AND STEEL INDUSTRY
Subcategory/Subdivision
A. Cokemaking
1. US - Biological
2. l&S - Physical-Chemical
3. Merchant - Biological
4. Merchant - Physical-Chemical
5. Beehive
*Cokemaking Total
B. Sintering
C. Ironmaking
D. Steelmaking
1. BOF: Semi-Wet
2. BOF: Wet-SC
3. BOF: Wet-OC
4. Open Hearth
5. EAF: Semi-Wet
6. EAF: Wet
*Steelmaking Total
E. Vacuum Degassing
F. Continuous Casting
G. Hot Forming
1. Primary C w/s
2. Primary C wo/s
3. Primary 3 w/8
4. Primary S wo/s
5. Section Carbon
6. Section Spec
7. Flat C HS&S
8. Flat S HS&S
9. Flat C Plate
10. Flat S Plate
11. Pipe & Tube-Carbon
12. Pipe & Tube-Spec
*Hot Forming Total
Capital
Annual
In-place
96.98
1.84
19.43
2.69
0.78
121.72
58.82
412.34
2.70
15.81
57.20
17.78
0.79
14.48
108.76
20.43
59.55
76.45
34.15
6.74
6.49
88.95
13.28
102.04
5.05
13.66
3.01
12.76
3.68
366.26
Required
41.50
3.70
2.45
0.00
0.00
47.65
5.07
22.40
1.61
0.00
1.42
0.00
0.22
0.00
3.25
7.47
4.84
20.78
9.85
0.00
0.76
19.05
4.17
23.26
0.14
6.49
0.18
9.35
0.00
94.03
In-Place
25.45
0.55
4.08
0.59
0.13
30.80
12.10
52.53
0.41
4.22
13.30
3.75
0.13
2.82
24.63
2.99
8.62
-29.62
-5.29
-0.75
-0.15
-0.96
-0.15
-4.83
0.23
-1.23
0.07
1.42
0.27
Required
9.51
0.88
0.54
0.00
0.00
10.93
1.34
2.74
0.24
0.00
0.34
0.00
0.03
0.00
0.61
1.11
0.76
2.66
1.32
0.00
0.00
2.48
0.30
3.06
0.02
0.87
0.02
1.23
0.00
-40.99
11.98
230
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TABIE VHI-1
EPT COST SUMMARY
IRON AN0 STEEL INDUSTRY
PAGE 2
Subcategory/Subdivision
H. Salt Bath Descaling
1. Oxidizing - B S/P
2. Oxidizing - B R/W/B
3. Oxidizing - B P/T
4. Oxidizing - Conl
5. Reducing - Batch
6. Reducing - Conl
*Salt Bach Descaling Total
I. Acid Pickling
1. Sulfuric-R/W/C-Neut
2. Sulfuric-S/S/?-Neut
3. Sulfuric-B/B/B-Neut
4. Sulfuric-P/T/0-Neut
5. Sulfuric-S/S/P Au
6. Sulfuric-R/W/C Au
7. Sulfuric-B/B/B Au
8. Sulfuric-P/T Au
9. Hydrochloric-R/V'C
10. Hydrochloric-S/S/V
11. Hydrochloric-P/T
12. Hydrochloric-S/S/P Ar
13. Combination-R/W/C
14. Conbination-B S/S/P
15. Coobination-C S/S/P
16. Coobination-B/B/B
17. Coobinalion-P/T
*Acid Pickling Total
Cold Forming
1. CR-Recirc Single
2. CR-Recirc Multi
CR-Combination
CR-DA Singla
CR-DA Multi
CW Pipe&Tube Water
CW Pipe & Tube Oil
*Cold Forming Total
In-place
0.58
0.86
0.76
1.53
0.61
0.20
4.54
Capital
144.65
0.20
0.02
0.00
0.16
0.00
0.00
0.38
5.38
In-Place
0.08
0.13
0.11
0.23
0.09
J).Q3
0.67
Annual
51.16
0.03
0.00
0.00
0.02
0.00
o.qo
0.05
0.51
1.86
0.00
0.42
0.00
0.00
0.00
0.00
0.15
1.65
0.10
0.00
0.14
0.03
0.08
0.00
0.44
3.37
13.13
2.93
1.92
0.54
0.58
0.00
0.12
0.75
22.87
0.19
-4.87
1.54
0.74
'6.54
0.20
0.61
0.13
1.23
0.00
0.08
0.00
0.00
0.00
0.00
0.02
1.46
0.01
O.C.
0.02
0.00
0.02
0.00
0.08
3.05
28.98
5.87
3.62
0.95
231
-------
NOTES: Co*L* are in million* of 7/1/78 dollar*.
Basia: Facilities in-place as of 7/1/81.
21L
Industry Total 1,491.49 205.96 168.73 35.27
!
TABLE VIII-1
BPT COST SUMMARY
IRON AND STEEL INDUSTRY
PACE 3
Capital Annual
Subcategory/Subdivision In-place Required In-Place Required ! »
; j
K. All-aline Cleaning ' •
1. Batch 1.67 0.31 0.21 0.04 {X
2. Continuoua 10.01 0.27 1.39 0.04 |
*Alk«line Cleaning Total 11.68 0.58 1.60 0.08 j
"t
1. Hot Coating |
1. Calv. SS wo/a 9.87 1.47 1.48 0.26 {
2. Calv. SS w/a 9.80 0.44 1.55 0.08
3. Calv. Wire wo/a 5.44 0.66 0.69 0.10 1 /
4. Calv. Wire w/s 1.10 0.66 0.17 0.10 ',
5. Terne wo/a 0.52 0.05 0.07 0.01 >
6. Terne w/a 1.32 0.32 0.20 0.05 i
7. Other SS wo/a 0.73 1.00 0.11 0.16 . !
8. Other SS w/s - !
9. Other Wire wo/s 0.31 0.00 0.04 0.00 j
10. Other Wire w/s , 0.74 0.00 0.00 0.00
*Hot Coating Total 29.83
Total 1,367.56
Confidential Plants 39.83
Costs for Component* Installed
Beyond BPT 84.10 0.00 11.TJ^ 0.00
I
-------
FIGURE Vlll-l
POTENTIAL FOR ACHIEVING
AN EFFLUENT LIMITATION
800
480 H
e 400
o
S80-
.§ 800
3 too
u.
jg £00
I I8°
O
100 H
so
EXAMPLE
SUBCATEOORY! IRONMAKINO
POLLUTANT: TSS XT THE BPT LEVEL
(PLANT
(PLAN? N)
(PLANT
•(PLANT tt)
IO SO SO 4O 6O «O TO SO 90 IOO IIO
TSS EFFLUENT CONCENTRATION (mg/l)
-r*-
I2O ISO ITO
: SOLID LINE REPRESENTS TBS LIMIT OP 0.02i kfl/kkg(IM/tOOO lb«)
NOTE: PLANTS ABOVE THE SOLID LINE DO NOT MEET TBS LIMITATIONS.
HOWEVER, THEY COULD ATTAIN THE APPROPRIATE LOAD BY EITHER
REDUCING THEIR PLOW Oft EFFLUENT CONCENTRATION AS SHOWN
BY THE DASHED ARROWS OR ANT COMBINATION OF THE TWO.
233
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GENERAL
SECTION IX
AFFLUENT QUALITY ATTAINABLE THROUGH
THE APPLICATION OF THE BEST AVAILABLE TECHNOLOGY
ECONOMICALLY ACHIEVABLE
Introduction
The effluent limitations which must be achieved by July 1, 1984 are to
specify the degree of effluent reduction attainable through the
application of the best available technology economically achievable.
Best available technology is not based upon an "average of the best"
performance within an industrial category, but is determined by
identifying the best control and treatment technology used by a
specific point source within the industrial subcategory. Also, where
a technology is readily transferable from one industry to another,
such technology may be identified as BAT technology.
Consideration was also given to:
1. The size and age of equipment and facilities involved.
2. The processes employed.
3. Non-water quality environmental impact (including energy
requirements).
4. The engineering aspects of the application of various types of
control techniques.
5. Process changes.
6. The cost of achieving the effluent reduction resulting from
application of BAT technology.
Best available technology may be the highest degree of control
technology that has been achieved or has been demonstrated to be
capable of being designed for plant scale operation up to and
including "no discharge" of pollutants. Although economic factors are
considered in the development, the level of control is intended to be
the top-of-the-line current technology, subject to limitations imposed
by economic and engineering feasibility. However, this level may be
characterized by some technical risk with respect to performance and
with respect to certainty of costs.
235
Preceding page blank
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Development of. BAT Effluent Limitations j
Model Treatment Systems
The Agency considered from two to five BAT alternative treatment
systems for each of the twelve steel industry subcategories. These j
alternatives are designed to oe compatible with the BPT model j
treatment systems in each subcategory from the standpoint of j
retrofitting the necessary water pollution control facilities. For \
those operations where BAT limitations more stringent than the i
respective BPT limitations have been promulgated, the required water f
pollution control facilities can be installed / without significant
retrofit costs. For most subcategories (Sintering, Ironmaking,
Steelmaking, Vacuum Degassing, and Continuous Casting), flows
amounting to only a few percent of the model BPT treatment system flow
rates require treatment in the BAT model treatment systems. For
cokemaking operations, additional biological treatment compatible with
the BPT model biological treatment system is the model BAT technology.
The BAT alternative treatment systems are reviewed in detail in the
respective subcategory reports of the development documents.
Model Treatment System Flow Rates
The Agency's selection of model BAT flow rates is highly subcategory
specific. In every case the Agency sought to determine the best flow
rate that could be achieved on a subcategory wide basis. In some
cases, the model BAT flow rates for the alternative treatment systems
are significantly more restrictive than the respective model BPT flow
rates. However, for most forming and finishing operations, where more
stringent BAT limitations were not promulgated, the model BAT flow
rates are the same as the model BPT flow rates. The Agency considered
zero discharge alternatives based upon evaporative technologies in all
subcategories. These technologies were rejected because of energy and
cost considerations.
A summary of the model BPT and BAT effluent flow rates for those
operations where more stringent BAT limitations were promulgated is
presented below:
Model BPT Model BAT
Subcateqory Flow Rate Flow Rate
A. Cokemaking
Iron and Steel 225 gal/ton 153 gal/ton
Merchant 240 170
b. Sintering 120 120 j
C. Ironmaking 125 70
D. Steelmaking
BOF, semi-wet 0 0
EOF, wet-supp. comb. 50 50
236
-------
BOF, wet-open comb. 110 110
Open Hearth, wet 110 110
EAF, semi-wet 0 0
EAF, wet 110 110
E. Vacuum Degassing 25 25
F. Continuous Casting 125 25
L. Hot Coating
. Fume Scrubbers 100 gpm 15gpm
The lower BAT model flow rates for cokemaking operations are based
upon recycle of barometric condenser cooling water, or replacement of
the barometric condenser with a surface condensor. The ironmaking BAT
model flow was set at 70 gal/ton based upon demonstrated performance
at plants in this subcategory. The BAT model flow rate for continuous
casting operations was set at 25 gal/ton based upon widespread
demonstration of flows of 25 gal/ton and less in that subcategory.
Finally, the hot coating fume scrubber BAT model flow of 15 gpm is
based upon recycle of fume scrubber wastewaters, a common practice in
the industry. The Agency did not set more restrictive BAT model flow
rates for the other operations listed above because it does not have
sufficient information and data at this time to demonstrate that more
restrictive flow rates are achievable on a subcategory-wide basis.
Reference is made to the respective subcategory reports for additional
information on the selection of the BAT model treatment system flow
rates.
Model Treatment System Effluent Quality
The performance standards for the model BAT treatment systems were
determined in the same .fashion as described in Section VIII for the
BPT limitations. Where more stringent BAT limitations were
promulgated, the Agency based the limitations upon the best performing
representative plant or plants in the subcategory; upon pilot scale
demonstration studies at plants within the subcategory; or upon pilot
scale demonstration studies at plants with similar, more highly
contaminated wastewaters. In all cases, however, the BAT limitations
are achieved on a full scale basis in the industry.
Summary of_ Changes From Proposed Regulation
Based upon comments on the proposed regulation, the Agency made
several changes in promulgating the final BAT effluent limitations.
For the most part, BAT effluent limitations more stringent than the
BPT limitations were promulgated for the basic steelmaking operations
and BAT limitations no more stringent than the BPT limittaions were
promulgated for the forming and finishing operations. These changes
are summarized below:
237
-------
Subcateqory
A. Cokemaking
B. Sintering
C. Ironmaking
D. Steelmaking
E. Vacuum Degassing
F. Continuous Casting
G. Hot Forming
H. Salt Bath Descaling
Changes from Proposed to Promulgated Regulation
While the model BAT treatment systems have
not changed substantially, slightly less
stringent limitations for all pollutants
were promulgated based upon analysis
of additional data received for the best
treatment facilities.
The selected model technology was changed
from alkaline chlorination to filtration.
Limitations for ammonia-N, total
cyanide, and phenols (4AAP) were provided
for sintering operations with wastewaters
that ate co-treated with ironmaking
wastewaters.
Less stringent ammonia-N limitations
were promulgated on the basis of comments
and data received on the proposed limit-
ations.
The selected mode' technology was changed
to delete post filtration of the lime
precipitation effluent. Slightly less
stringent limitations for lead and zinc
were promulgated and the limitations
for chromium were deleted.
The model treatment technology was
changed to lime precipitation and
sedimentation from filtration.
Less stringent limitations for
lead and zinc were promulgated
and the limitation for chromium was
deleted. The limitations for these
operations are now consistent with
those for Steelmaking operations.
High rate recycle of hot forming
wastewaters was not selected as the
model BAT treatment technology.
Thus, BAT limitations for hot
forming operations were not
promulgated.
Filtration of the BPT model
treatment system effluent was
not selected as the model BAT
treatment system. Thus, BAT
limitations no more stringent
than the BPT limitations were
promulgated.
23G
-------
I. Acid Pickling
J. Cold Forming
K. Alkaline Cleaning
L. Hot Coating
Cascade rinsing of acid pickling
rinsewaters was not selected as
the BAT model treatment system. Thus,
BAT limitations no more stringent than
the BPT limitations were promulgated.
BAT limitations no more stringent than
the BPT limitations were promulgated.
BAT limitations wete not proposed
and not promulgated.
Cascade rinsing of hot coating
rinsewaters was not selected as the
model BAT treatment technology.
BAT limitations no more stringent
than the BPT limitations were
promulgated for those hot coating
operations without fume scrubbers.
More stringent BAT limitations were
promulgated for those hot coating
operations with fume scrubbers.
Best Available Technology Effluent Limitations and Associated Costs
..*
Based upon the information contained in Sections II through VI11 of
this report and upon data presented in the respective subcategory
reports, various treatment systems were considered for the BAT level
of treatment. A short description of the model BAT treatment systems
is presented in Table 1-15. The BAT effluent limitations are
summarized in Table 1-4. The costs associated with the model BAT
systems are summarized in Table IX-14 by subcategory. As with the BPT
effluent limitations, the Agency has concluded that the effluent
reduction benefits associated with the selected BAT limitations
justify the costs and non-water quality environmental impacts,
including energy consumption, water consumption, air pollution, and
solid waste generation.
Co-Treatment with Non-Steel Industry Finishing frastewaters
The steel
coated with
This regulation contains
hot coating processes (i.e.
baths of zinc, terne metal,
does not include specific
industry produces a number of finished products that are
various metals for protective or decorative purposes.
effluent limitations and standards for the
, coating of steel by immersion in molten
or other metals). However, the regulation
limitations for cadmium, copper, chromium,
nickel, tin, and zinc electroplating operations found at many steel
plants. It is common practice in the industry to co-treat wastewaters
from these operations with wastewaters from acid pickling, cold
rolling, alkaline cleaning, and hot coating operations. Often,
pretreatment of wastestreams with high levels of cyanide or a
particular metal is practiced prior to final neutralization and
settling (i.e., reduction of hexavalent chromium; separate
-------
neutralization and settling for zinc). The model BPT and BAT
treatment systems for steel industry finishing operations are
installed at many co-treatment plants and, effluent data from some of
the co-treatment systems were considered in developing the limitations
and standards in this regulation.
Application of the limitations and standards contained in this
regulation to plants with electroplating operations without any
allowance for those operations will present problems, both to permit
writers and to the industry. The following guidance is provided to
permit writers to develop plant specific NPDES permit conditions for
these facilities:
a. Treatment Plants with BPT/BAT Treatment Facilities In-Place
1) Determine the plant specific BPT/BAT effluent
limitations for those steel industry finishing
operations included in this regulation. Compare the
mass loadings to current performance of the treatment
facility in question for periods of relatively high
production.
2) If the applicable effluent limitations fcr the steel
operations included in this regulation are determined
not to be achievable considering appropriate historical
performance data, alternate BAT limitations should be
developed for those plants with well operated treatment
facilities. These treatment facilities should include
all of the BPT/BAT treatment components and not include
a substantial amount of cooling waters, surface runoff,
or process wastewaters from hot forming or any of the
basic steelmaking operations. These alternate mass
effluent limitations should be based upon the current
performance of the treatment facility on a concen-
tration basis, and treatment system flow rates which
take into account those finishing operations included
in this regulation and flows from the electroplating
operations. In some cases, in-process flow reduction
including recycle of fume scrubbers, reduction in
rinsewater flows, etc., may ce required to further
reduce the discharge from current levels. In general,
the concentrations determined from actual performance
data should be in the immediate range of those
concentrations presented in the Development Document
used to develop the BPT and BAT effluent limitations.
b. Treatment Plants Without BPT/BAT Treatment Facilities In-
Place
1) Determine the plant specific BPT/BAT effluent
limitations for those steel industry finishing
operations included in this regulation.
2) Determine an allowance for the electroplating
operations based upon the process flow rates from those
operations (after appropriate flow minimization steps
are implemented i.e., fume scrubber recycle), and the
240
' W
e>.
m
'&
•&
I
-------
• performance data presented in the Development Document
; for similar co-treatment systems.
i
i Technical assistance for permit writers may be obtained from the
i Effluent Guidelines Division for developing limitations for treatment
| systems that treat wastewaters from operations covered by this J
regulation and wastewaters from other operations. '•
} • i-
I »
ii
241
-------
TABLE IX-1
BAT COST SUMMARY
IRON AND STEEL INDUSTRY
Capital
Subcategory/Subdi vision
A. Cokeauking
1. US - Biological
2. US - Physical-Chemical
3. Merchant - Biological
4. Merchant - Physical-Chemical
•Cokemaking Total
B. Sintering
C* Ironmaking
D. SCeelmaking
1. BOF: Semi-Wet
2. BOF.' Wet-SC
3. BOF: Wet-OC
4. Open Hearth
S. EAF: Semi-Wet
6. EAF: Wet
*Steelm*king Total
E. Vacuum Degassing
F. Continuous Casting
L. Bot Coating
1. Galv. SS wo/s
2. Galv. SS w/s
3. Galv. Wire wo/s
4. Galv. Wire w/s
5. Terne wo/s
6. Terne w/s
7. Other SS wo/s
8. Other SS w/s
9. Other Wire wo/s
10. Other Wire w/s
*Hot Coating Total
Total
Confidential Plants
Industry Total
In- pi ace
4.83
3.74
0.39
2.16
11.12
0.51
7.63
-
1.20
0.56
0.33
-
0.46
2.55
0.20
0.82
-
0.31
-
0.04
-
0.00
-
-
-
0.10
0.45
23.28
0.80
24.08
Required
28.62
0.00
4.33
0.00
32.95
5.51
23.20
-
0.34
5.32
1.44
-
1.09
8.19
2.82
2.23
-
0.32
-
0.03
-
0.16
-
-
-
0.00
0.51
75.41
1.94
77.35
Annual
la-Place
0.92
1.62
0.07
0.98
3.59
0.05
2.27
-
0.16
0.08
0.05
-
0.06
0.35
0.03
0.11
~
0.04
-
0.01
-
0.00
-
-
_
0.00
0.05
6.45
0.18
6.63
Required
6.96
0.00
0.94
0.00
7.90
0.74
6.77
-
0.06
0.78
0.23
-
0.17
1.24
0.39
0.31
-
0.04
-
0.00
-
0.02
-
-
_
0.00
0.06
17.41
0.43
17.84
NOTES: Costs are in Billions of 7/1/78 dollars.
Basis: Facilities in-place as of 7/1/81.
: BAT limitations equal to BPT are being promulgated in the
other subcalegories/aubdivisions. There is no additional
costs in these subcategories/subdivisions.
242
-------
ZF-
|
• s
K K
5=
8s
o
&
&
7 R 5
£ "5^
** MOW
1
IS
V • *
en IB tj
K K
il
f :
5 S
I £-5
I O h.
K K
K K
XX KM
K K K K K
i
C -* •
Q «
> *•
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Si
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•S ° S £•
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IS s
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243
-------
VOLUME I
SECTION X
BEST CONVENTIONAL POLLUTANT CONTROL TECHNOLOGY
Introduction
The 1977 Amendments added Section 301(b)(2)(E) to the Act,
establishing "best conventional pollutant control technology" (BCT)
for discharges of conventional pollutants from existing industrial
point sources. Conventional pollutants are those defined in Section
304(a)(4) [biochemical oxygen demanding pollutants (BOB$), total
suspended solids (TSS), fecal coliform, and pH], and any additional
pollutants defined by the Administrator as "conventional" (oil and
grease, 44 FR 44501, July 30, 1979).
BCT is not an additional limitation but replaces BAT for the control
of conventional pollutants. In addition to other factors specified in
Section 304{b)(4)(B), the Act requires that BCT limitations be
assessed in light of a two part "cost-reasonableness" test. American
Paper Institute v. EPA, 660 F. 2d 954 (4th Cir. 1981). The first test
compares the cost for private industry to reduce its conventional
pollutants with the costs at publicly owned treatment works for
similar levels of reduction in their discharge of these pollutants.
The second test examines the cost-effectiveness of additional
industrial treatment beyond BPT. EPA must find that limitations are
"reasonable" under both tests before establisning them as BCT. In no
case may BAT be less stringent than BPT.
Because of the remand in American Paper Institute v. EPA (No. 79-115),
the regulation does not contain BCT limitations except for those
operations for which the BAT limitations are not more stringent than
the respective BPT limitations.
245
Preceding page blank
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VOLUME I
SECTION XI
EFFLUENT QUALITY ATTAINABLE THROUGH THE
APPLICATION OF NEW SOURCE PERFORMANCE STANDARDS
Introduction
NSPS are to specify the degree of effluent reduction achievable
through the application of the best available demonstrated control
technology, processes, operating methods, or other alternatives,
including, where applicable, a standard requiring no discharge of
pollutants.
For new source plants, a zero discharge of pollutants limit was sought
for each subcategory. There are several facilities in some
subcategories that demonstrate zero discharge. However, the Agency
determined that for most of these subcategories zero discharge is not
attainable for all new sources without the use of costly evaporative
technologies. For these wastewater operations, treatment systems at
lowest achievable flow rates have been considered.
Because new plants can be designed with water conservation and
innovative technology in mind, costs can be minimized by treating the
lowest possible wastewater flows. No considerations had to be given
to the "add-on" approach that was characteristic of the BPT and BAT
systems and therefore the NSPS Alternatives consider the most
efficient treatment components and systems. NSPS systems are
generally the same as the BAT systems; however, in some subcategories,
alternate treatment components are included.
Identification of NSPS
The alternative treatment systems considered for NSPS are the same as
the alternatives considered for BAT with minor exceptions. However,
as noted above, in many subcategories lower discharge flows are
considered for NSPS. Since the criteria for NSPS is to consider only
the very best systems, the lowest demonstrated flow could be used to
develop NSPS standards. Table XI-I lists the treatment systems used
as models for NSPS. The standards associated with the model NSPS
systems are summarized in Table 1-15. Additional details on the
development of NSPS are provided in the individual subcategory
reports. All of the NSPS are demonstrated in the steel industry.
NSPS Costs
The Agency did not estimate the number of new source plants to be
built. However, the Agency did consider the potential economic
impacts of NSPS in Economic Analysis of Effluent Guidelines -
247
Preceding page blank
-------
Integrated Iron and Steel Industry. Model costs for the NSPS systems
are detailed in the individual subcategory reports.
24C
-------
VOLUME I
SECTION XII
PRETREATMENT STANDARDS FOR PLANTS DISCHARGING
TO PUBLICLY OWNED TREATMENT WORKS
Introduction
The industry discharges untreated or partially treated wastewaters to
publicly owned treatment works (POTWs) from operations in nearly every
subcategory. Table XII-1 lists all plants which reported discharges
to POTWs. In the individual subcategory reports, two classes of
discharges to POTWs were addressed: existing sources and new sources. jj
Also, the national pretreatment standards developed for indirect j
discharges fall into two separate groups: prohibited discharges, )
covering all POTW users, and categorical standards applying to j
specific industrial subcategories.
As was done for BAT, BCT and NSPS, various alternative treatment
systems were considered for pretreatment standards. Up to six j
alternatives were considered for each subcategory. f
National Pretreatment Standards I
The Agency has developed national standards that apply to all POTW j
discharges. For detailed information on the Agency's approach to
Pretreatment Standards refer to 46 FR 9404 et seq, "General
Pretreatment Regulations for Existing and New Sources of Pollution,
(January 28, 1981). See also 47 FR 4518 (February 1, 1982). In
particular, Part 403, Section 403.5 et. seq. describes national
standards, prohibited discharges and categorical standards, POTW
pretreatment programs, and a national pretreatment strategy. j
1
Categorical Pretreatment Standards
The Agency based the categorical pretreatment standards for the steel
industry on the minimization of pass through of toxic pollutants at
POTWs. For each subcategory, the Agency compared the removal rates
for each toxic pollutant limited by the PSES to the removal rate for
that pollutant at well operated POTWs. The POTW removal rates were
determined through an extensive study conducted by the Agency at over
forty POTWs. The POTW removal rates are presented below:
Toxic Pollutant POTW Removal Rate
Cadmium 38%
Chromium 65%
Copper 58%
Lead ' 48%
Nickel 19%
249
I
a
-------
Silver 66%
Zinc 65%
Cyanide 52%
As shown in the respective subcategory reports, the pretreatment
alternatives selected by the Agency in all cases provide for
significantly more removal of toxic pollutants than would occur if
steel industry wastewaters were discharged to POTWs untreated. Thus,
the pass through of these pollutants at POTWs will be minimized.
Except for the Cokemaking subcategory, all selected PSES and PSNS
alternatives are the same as the respective BAT and NSPS alternatives.
For cokemaking operations, the Agency's selected PSES alternative is
based upon the same physical/chemical pretreatment the industry
provides for its on-site coke plant biological treatment systems.
The PSES and PSNS are set out in Tables 1-8 and 1-6, respectively.
The associated industry-wide PSES costs are presented in Table XI1-14.
PSNS model treatment system costs are presented in the respective
subcategory reports.
250
-------
TABLE Xll-l
LIST OF PLANTS WITH INDIRECT DISCHARGES TO POTW SYSTEMS
PLANT
00208
0020C
0024A
0048D
0048F
0060
00606
0060H
00601
0060L
0060M
0060R
OQ60S
0068
0088
00886
OII2F
01 120
01121
01368
OI36C
OI76C
OI76D
0180
0212
0248A
O256A
0256K
0256N
OZ64
O264A
0264 C
0264D
0280B
0320
0380
0384A
0396A
0396C
0396D
0432B
0432E
0432 J
0432L
251
-------
TABLE Xll-l
LIST OF POTW (XSCHAR6ER8
PAGE 2
0440A
0444
0448A
0460A
O4608
0460C
0460F
04600
O460H
O464B
0464C
0526
O548B
0580
05808
0560C
0580 E
0580F
05800
05848
0636
064OA
06408
0648
06 56 A
06728
0684 H
0684 K
0684 Z
0696A
0740A
0760
0776C
07T60
0776J
0792A
0792C
0810
0856F
0860H
0884E
0936
0946A
0948B
0948C
TOTAL
(90 SUM)
X
X
X
X
X
X
X
X
18
1
X
2
X
X
2
0
X
1
0
X
X
X
K
X
7
X
X
X
6
X
*
X.
X
X
X
X
9
X
X
3
X
1
X
X
2
1
X
X
X
X
X
X
X
X
X
X
X
X
X
X
29
X
X
X
X
X
X
9
X
X
X
X
X
X
X
X
x;
X
X
X
18
X
3
X
3
X
X
X
X
X
X
X
X
X
X
X
X
16
X
X
X
X
X
X
X
X
X.
X
X
20
252
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TABLE XII-2
PJtETREATWKT COST SUMMARY
IRON AND STEEL INDUSTRY
Subcategory/Subdivision
A. Cok«tMking
1. US - Planes
2. Merchant - Plants
*Coke*aking Total
B. Sintering
C. Ironauking
D. SteelBaking
1. BOF: Seat-Wet
2. BOPi Wet-SC
3. BOF: Wet-OC
4. Open Hearth
5. EAT: Srai-Wet
6. EAT: Wet
*Steelauking Total
E. Vacuum1 Degassing
F. Continuous Canting
C. Hot Forning
1. Primary C w/s
2. Primary C wo/s
3. Primary S «/s
4. Primary S wo/s
5. Section Carbon
6. Section Spec
7. Plat C HS&S
8. Plat S HS&S
9. Flat C Plate
10. Flat S Plate
11. Pipe & Tube*Carbon
li. Pipe & Tube-Spec
•Hot Forming Total
Capital
In-placc Required
28.21
2.66
30.87
3.23
13.21
3.06
5.73
2.90
11.69
9.01
3.93
5.6*
0.67
11.47
0.05
3.39
2.81
1.16
7.52
7.41
14.93
0.36
0.65
0.00
0.00
0.00
0.00
0.34
0.43
0.00
0.30
2.66
0.00
0.00
0.00
0.00
In-Place
7.04
0.?6
7.60
0.78
2.26
0.82
1.30
0.55
2.67
1.34
-1.08
-0.29
-0.08
0.00
-0.01
-0.33
0.07
0.14
Annual
Required
1.12
1.45
2.57
0,05
0.18
0.00
0.00
0.00
0.00
0.05
0.05
0.00
0.04
0.18
0.00
0.00
0.00
0.00
29.12
3.39
-1.58
0.27
253
I /
-------
TABU XI1-2
PRmtZATKEKT COST SUMMARY
IROM AXO STEEL IKDUSTRY
PACE 2
SubcattKorT/Subdivision.
H. Salt Bath Descaling
1. Oxidizing - B S/P
2. Oxidizing - B R/W/B
3. Oxidizing - B P/T
4. Oxidizing - Cont
5. Reducing - Batch
6. Reducing - Cont
*S«H Bath Descaling Total
I. Acid Pickling
1. Sulfuric-R/U/C-Heut
2. Sulfuric-S/S/P-Neut
3. Sulfuric-B/B/6-Neut
4. Sulfuric-P/T/0-Neut
5. Sulfuric-S/S/P Au
6. Sulfuric-R/W/C Au
7. SuHuric-8/B/B Au
8. Sulfuric-P/T Au
9. Hydrochlorir-R/W/C
10. Hydrochloric-S/S/P
11. Hydrochloric-P/T
12. Hydrochloric-S/S/P Ar
13. Co»bination-R/W/C
14. Coebination-B S/S/P
IS. Covbination-C S/S/tf
16. Coobination-B/B/B
17. Cocbination-P/T
•Acid Pickling Total
J. Cold Foraing
1. CR-Rftcirc Single
2. CR-Recirc Hulti
J. Cft-Co«biuation
4. CR-DA Single
5. CR-DA Multi
6. CW Pipe&Tube Water
7. CW PipeiTubc Oil
•Cold Forming Total
Capital
In-place
0.0?
0.09
0.04
0.20
3.05
1.11
0.53
1.42
1.18
1.74
0.01
1.28
11.03
0.00
0.00
0.09
0.09
0.20
0.72
0.08
1.00
3.82
1.44
1.18
0.64
3.52 .
0.02
0.02
1.93
0.33
0.11
0.85
13.86
0.03
0.03
Annual
In-Place
0.01
0.01
0.01
0.03
1.05
0.80
0.23
0.41
0.40
1.59
0.00
0.39
0.00
0.15
0.07
5.09
0.00
0.00
Required
0.03
0.11
0.01
0.15
1.16
0.79
0.42
0.20
0.75
0.01
0.00
0.48
0.12
0.03
0.21
4.17
0.00
0.00
254
-------
TABLE XI1-2
PUTREAiHEirr COST SOTtoARY
IKON AND STEEL 1NDUSTIY
PACE 3
Subcatetory/Subdiviaion
K. Alkaline Cleaning
1. Batch
2. Continuous
*AHc«Hn« Cleaning Total
L. Mot Coating
1. Calv. SS wo/e
2. Calv. SS »/e
3. Calv. Wir« wo/»
4. Calv. Wire «/a
5. Ttrn« wo/a
6. Tern* «/•
7. Other SS wo/a
8. Other SS w/e
9. Other Wire vo/a
10. Other Wire w/a
•Hot Coating Total
Total
Confidential Planta
Coata for Coaponente tnatalled
Beyond PSES
Induatry Total
Capital
Annual
In-place
0.00
0.47
0.47
0.27
0.14
0.92
1.24
0.01
0.07
NOTES: Coata in aillions of 7/1/76 dollars.
Basin Facilitiea ir.-place aa of 7/1/81.
255
0.00
0.75
0.00
0.37
0.70
0.0)
0.43
In-Plaee
0.00
0.06
0.06
0.04
0.02
0.13
0.18
0.00
0.01
0.00
0.00
0.00
0.10
0.00
0.0}
0.11
0.01
0.06
2.6S
111.57
2.14
18. 27
131.98
2.30
36.89
4.02
_ 0.00
40.91
0.38
18.64
0.70
2.75
22.09
0.33
7.77
0.85
0.00
8.62
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VOLUME I
SECTION XIII
ACKNOWLEDGEMENTS
The field sampling and analysis for this project and the initial
drafts of this report were prepared under Contracts No. 68-01-4730 and
68-01-5827 by the Cyrus Wm. Rice Division of NUS Corporation. Th*-
final report has been revised substantially by and at the direction of
EPA personnel
The preparation and writing of the initial drafts of this document was
accomplished through the efforts of Mr. Thomas J. Centi, Project
Manager, Mr. J. Steven Paquette, Deputy Project Manager, Mr. Joseph
A. Boros Mr. Patrick C. Falvey, Mr. Edward D. Maruhnich, Mr. Wayne
M. Neeley, Mr. William D. Wall, Mr. David E. Soltis, Mr. Michael C.
Runatz, Ms. Debra M. Wroblewski, Ms. Joan 0. Knapp, and Mr. Joseph J.
Tarantino.
The Cyrus W. Rice Field and sampling programs were conducted under the
leadership of Mr. Richard C. Rice, Mr. Robert J. Ondof and Mr. Matthew
J. Walsh. Laboratory and analytical servies were conducted under the
guidance of Miss C. Ellen Gonter, Mrs. Linda A. Deans and Mr. Gary A.
Burns. The drawings contained within and general engineering services
were provided by the RICE drafting room under the supervision of Mr.
Albert M. Finke. Computer services and data analysis were conducted
under the supervision of Mr. Henry K. Hess.
The project was conducted by the Environmental Protection Agency, Mr.
Ernst P. Hall, P.E. Chief, Metals and Machinery Branch, OWWH, Mr.
Edward L. Dulaney, P.E., Senior Project Officer; Mr. Gary A. Amendoia,
P.E., Senior Iron and Steel Specialist, Mr. Terry N. Oda, National
Steel Industry Expert, Messers. Sidney C. Jackson, Dwight Hlustick,
Michael Hart, John k'lliams, Dr. Robert W. Hardy, and Dennis Ruddy,
Assistant Project Officers, and Messers. J. Daniel Berry and Barry
Malter, Office of General Counsel. The contributions of
Mr.
Walter J. Hunt, former Branch Chief, are also acknowledged.
The cooperation of the American Iron and Steel Institute, and more
specifically, the individual steel companies whose plants were sampled
and who submitted detailed information in response to questionnaires,
is gratefully appreciated. The operations and plants visited were the
property of the following companies: Jones & Laughlin Steel
Corporation, Armco Inc., Ford Motor Company, Lone Star Steel
Corporation, Bethlehem Steel Corporation, Inland Steel Company, Donner
Hanna Coke Corporation, Interlake, Inc., Wisconsin Ste?l Division of
Envirodyne Company, Jewell Smokeless Coal Corporation, National Steel
Corporation, United States Steel Corporation, Kaiser Steel
Corporation, Shenango, Inc., Koppers Company, Eastmet Corporation,
Northwestern Steel and Wire Company, CF&I Steel Corporation, Allegheny
257
frececfing page Wank
-------
Ludlum Steel Corporation, Wheeling-Pittsburgh Steel Corporation,
Republic Steel Corporation, Lukens Steel Company, Laclede Steel
Company, Plymouth Tube Co., The Stanley Steel Division, Youngstown
Sheet & Tube Co., McLouth Steel Corp., Carpenter Technology, Universal
Cyclops, Joslyn Steel, Crucible Inc., Babcock & Wilcox Company,
Washington Steel, and Jessop Steel.
Acknowledgement and appreciation is also givenf to the secretarial
staff of the RICE Division, of NUS (Ms. Rane Wagner, Ms. Donna Guter
and Ms. Lee Lewis) and to the word processing staff of the Effluent
Guidelines Division (Ms. Kaye Storey, Ms. Pearl Smith, Ms. Carol Swann
and Ms. Glenda Clarke) for their efforts in the typing of drafts,
necessary revisions, and preparation of this effluent guidelines
document.
258
-------
VOLUME I
SECTION XIV
REFERENCES
1. Adams, C.E., Jr., "Treatment of a High Strength Phenolic and
Ammonia Wastestream By Single and Multi-Stage Activated Sludge
Processes", Proceedings of the 29th Industrial Waste Conference,
Purdue University, pp. 617-630 (1974~T~.
2. Adams, C.E., Stein, R.M., Eckenfelder, W.W., Jr., "Treatment of
Two Coke Plant Wastewaters to Meet Guideline Criteria",
Proceedings of the 29th Industrial Waste Conference, Purdue
University, pp. 864-880 (1974).
3. American Iron and Steel Institute, "Annual Statistical Report,
1976". Washington, D.C.
4. American Iron and Steel Institute, Directory of_ Iron and Steel
Works of the United States and Canada, American Iron and Steel
Institute, New York (1976).
5. Anthony, M.T., "Future of the Steel Industry In The West", Iron
and Steel Engineer, pp. 54-55 (September, 1974).
6. "Armco's Innovative Electric Furnace Practice", Journal o_f
Metals, pp. 43-44 (November, 1974).
7. Atkins, P.F., Jr., Scherger, D.A., Barnes, R.A. and Evans, F.L.
Ill, "Ammonia Removal By Physical Chemical Treatment", Water
Pollution Control Federation, Journal, 45 (11), pp. 2372-2388
(November, 1973).
8. Balden, A.R. and Scholl, E.L., "The Treatment of Industrial
Wastewaters for Reuse, Closing the Cycle", Proceedings of_ the
28th Industrial Waste Conference, Purdue University, pp. 874-880
TT9T3).
9. Becker, A.P., Lachajcztk, T.M., "Review of Water Usage in the
Iron and Steel Industry: Blast Furnace and Hot Forming
Subcategories" Presented at the U.S. EPA Symposium on Iron and
Steel Pollution Abatement Technology, October 1981.
10. Beckman, W.J., Avendt, R.J., Mulligan, T.J. and Kehrberger, G.J.,
"Combined Carbon Oxidation Nitrification," Journal of. the Water
Pollution Control Federation, 44, October 10, 1972, p. 1916.
11. Bennett, K.W., "Mini-Midi Mills Show Larger Amount of Clout",
Iron Age, 213 (15), pp. MP-9-MP-38 (October 11, 1976).
259
B?Pi
^
-------
12. Bernardin, F.E., "Cyanide Detoxification Using Adsorption and
Catalytic Oxidation on Granular Activated Carbon," Journal of the
Water Pollution Control Federation^ 45, 2, February, 1973, p.
221 .
13. Black, H.H., McDermott, G.N., Henderson, C., Moore W.A. and
Pohren, H.R., "Industrial Wastes Guide", -Industrial Waste
Conference, Purdue University (May 15-17, 1956).
14. Borland, C.C. and Cruse, C.L., "Direct Reduction - How Is Quality
Measured?", Ironmakinq Proceedings, The Metallurgical Society of
A.I.M.E.. Toronto, 34. pp. 206-215 (1975).
15. Brinn, D.G. and Doris, R.L., "Basic Oxygen Steelmaking: A
Bibliography of Published Literature", British Steel Corporation
Research Report, Section 7, pp. 25-28.
16. Brough, John R. and Voges, Thomas F., "Basic Oxygen Process Water
Treatment", Proceedings, Industrial Waste Conference, Purdue
University. 24th, pp. 762-769 (1969).
17. Burns and Roe, Draft Development Document, Electric Power
Industry, November 1974.
18. Burns & McDonald, Evaluation of Wet Versus Dry Cooling Systems,
January, 1974.
19. Calgon Corporation Application Bulletin, "Calgon Cyanide
Destruction System", (1971).
20. Carson, James, E., Atmospheric Impacts of Evaporative Cooling
Systems, ANL/ES-53.
21. Cartwright, W.F., "Research Might Help to Solve Coking Industry
Problems, Gas World, 164, p. 497 (November 12, 1966).
22. Catchpole, J.R., "The Treatment and Disposal of Effluents in the
Gas and Coke Industry", Air and Water Pollution in the Iron and
Steel Industry, Iron and Steel Institute Special Report No.
1961. pp. 219-225 (1958).
23. Chen, Kenneth Y., "Kinetics of Oxidation of Aqueous Sulfide by
02", Environmental Science and Technology, 6_, p. 529 (June,
1972).
24. Cheremisnoff, P.N., "Biological Wastewater Treatment", Pollution
Engineering, '8 (9), pp. 32-38 (September, 1976).
25. Cheremisinoff, P.N., Perna, A.J. and Sevaszek, E.R., "Controlling
Organic Pollutants In Industrial Wastewaters", Industrial Wastes,
2J. (5), pp. 26-35 (September-October, 1975).
260
-------
26. "Clean System Quenches Coke", Iron Age. 211 (14), p. 25 (April
5, 1973).
27. "Controlling Quenching Emissions", Iron and Steel Engineer, 53
(12), p. 21 (December, 1976).
28. Cook, W.R. and Rankin, L.V., "Polymers Solve Waste Water
Problems", Iron and Steel Engineer, pp. 43-46 (May, 1974).
29. Cooper, R.L., "Methods of Approach to Coke Oven Effluent
Problems", Air and Water Pollution in the Iron and Steel
Industry, Iron and Steel Institute Special Report NQ^ 61, pp.
198-202 (19587.
30. Cooper, R.L. and Catchpole, J.R., "The Biological Treatment of
Coke Oven Effluents", The Coke Oven Manager's Yearbook, pp.
146-177 (1967).
31. Cooper, R.L. and Catchpole, J.R., "Biological Treatment of
Phenolic Wastes", Management of Water jji the Iron and Steel
Institute Special Report No. 128, pp. 97-102 (1970).
32. Cousins, W.G. and Mindler, A.B., "Tertiary Treatment of Weak
Ammonia Liquor", JWPCF. 44, 4 607-618 (April, 1972).
33. Cruver, J.E. and Nusbaum, I., "Application of Reverse Osmosis to
Wastewater Treatment," Journal WPCF, Volume 45, No. 2, February,
1974.
34. Davis, R.F., Jr. and Cekela, V.W., Jr., "Pipeline Charging
Preheated Coal to Coke Ovens", Ironmaking Proceedings, The
Metallurgical Socitry of A.I.M.E., Toronto, 34, pp. 339-349
(1975).
35. Decaigny, Roger A., "Blast Furnace Gas Washer Removes Cyanides,
Ammonia, Iron, and Phenol", Proceedings, 25th Industrial Waste
Conference, Purdue University, pp. 512-517 (1970).
35. DeFalco, A.J., "Biological Treatment of Coke Plant Waste", Iron
and Steel Engineer, pp. 39-41 (June, 1976).
37. DeJohn, P.B., Adams, A.D., "Treatment of Oil Refinery Wastewaters
with Granular and Powdered Activated Carbon", Purdue Industrial
Waste Conference.
S8. Directory of Iron and Steel Plants, Steel Publications, Inc..
39. Directory of_ the Iron and Steel Works of. the World, Metal
Bulletins Books, Ltd., London, 5th edition.
40. Donovan, E.J., Jr., Treatment of Wastewater for Steel Cold
Finishing Mills, Water and Wastes Engineering, November, 1970.
261
-------
41. DuMond, T.C., "Mag-Coke Creates Big Stir in Desulfurization",
Iron Age, 211 (24), pp. 75-77 (June 14, 1973).
42. Dunlap, R.W. and McMichael, F.C., "Reducing Coke Plant Effluent",
Environmental Science and Technology, 10 (7), pp. 654-657 (July,
1976).
43. Duvel, W.A. and Helfgott, T., "Removal of Wastewater Organics by
Reverse Osmosis," Journal WPCF, Volume 47, No. 1_, January, 1975.
44. Edgar, W.D. and Muller, J.M., "The Status of Coke Oven Pollution
Control", AIME, Cleveland, Ohio (April, 1973).
45. Effect of Geographical Variation on Performance of Recirculating
Cooling Ponds, EPA-660/2-74-085.
46. Eisenhauer, Hugh R., "The Ozonation of Phenolic Wastes", Journal
of the Water Pollution Control Federation, p. 1887 (November,
1968).
47. Elder, R.G., "Zinc Control in a Blast Furnace Gas Wash Water
Recircuiation System", Presented at the U.S. EPA Symposium on
Iron and Steel Pollution Abatement Technology for 1981, October
1981 .
48. Elliott, J.F., "Direct Reduction of Iron Ores - Processes and
Products", Ironmaking Proceedings, The Metallurgical Society of
A.I.M.E., Toronto, 34, pp. 216-227 (1975).
49. Environmental Protection Agency, "Analytical Methods for the
Verification Phase of the BAT Review", Office of_ Water, and
Hazardous Materials (June, 1977).
50. Environmental Protection Agency, "Biological Removal of Carbon
and Nitrogen Compounds from Coke Plant Wastes", Office of
Research and Monitoring, Washington, D.C. (April, 1973).
51. Environmental Protection Agency, Draft Development Document for
Effluent Limitations and Guidelines and Standards of Performance,
Alloy and Stainless Steel Industry, Datagraphics, _I_n.c_._ (January,
1974).
52. Environmental Protection Agency, "Industry Profile Study on Blast
Furnace and Basic Steel Products ," C.W. Rice Division -NUS
Corporation for EPA, Washington, D.C. (December, 1971).
53. Environmental Protection Agency, "Pollution Control of Blast
Furnace Gas Scrubbers Through Recircuiation". Office of Research
and Monitoring, Washington, D.C. (Project No. 12010EDY).
54. Environmental Protection Agency, "Sampling and Analysis
Procedures for Screening of Industrial Effluents for Priority
262
-------
Pollutants", Environmental Monitoring and Support Laboratory,
Cincinnati, Ohio (March, 1977 revised April, 1977).
j
55. Environmental Protection Agency, "Steel Making Segment of the !
Iron and Steel Manufacturing Point Source Category", Office of )
Water and Hazardous Materials, Washington, D.C. (June, 1974). j
56. Environmental Protection Agency, "Water Pollution Control |
Practices in the Carbon and Alloy Steel Industries", EPA, j
Washington, D.C. (September 1, 1972). ||
i I
57. Environmental Protection Agency, "Water Pollution Control ;
Practices in the Carbon and Alloy Steel Industries", Progress !
Reports for the Months of September and October, 1972 (Project
No. R800625). j
58. Environmental Steel, The Council of_ Economic Priorities. }
59. Fair, G.M., Geyer, I.C., Okum, D.P., Water and Wastewater '
Engineering, Volume J_, Water Spray and Wastewater Removal. '•
60. Flynn, B.P., "A Model for the Powdered Activated Carbon -
Activated Sludge Treatment System; Purdue Industrial Waste
Conference.
61. Foltz, V.W., Thompson, R.J., "Armco Develops Cold Mill Waste Oil
Treatment Process", Water and Wastes Engineering, March 1970.
62. Ford, D.L., "Putting Activated Carbon in Perspective in 1983
Guidelines," National Conference on Treatment and Disposal of
Industrial Waste Waters and Residues, April 26-28, 1977.
63. Ford, D.L., Elton, Richard L., "Removal of Oil and Grease From
Industrial Wastewaters", Chemical Engineering, Oct. 17, 1977.
64. Fraust, C.L., "Modifying A Conventional Chemical Waste Treatment
Plant to Handle Fluoride and Ammonia Wastes", Plating and Surface
Finishing, p. 1048-1052 (November, 1975.)
65. Gelb, B.A., "The Cost of Complying with Federal Water Pollution
Law", Industrial Water Engineering, 12 (6), pp. 6-9 (December,
1975 - January, 1976).
66. George, H.D. and Boardman, E.B., "IMS - Grangcold Pelletizing
System For Steel Mill Waste Material", Iron and Steel Engineer,
pp. 60-64 (November, 1973).
67. Goldstein, M., "2. Economics of Treating Cyanide Wastes",
Pollutlon Engineering, pp. 36-38 (March, 1976).
86. Gordon, C.K., "Continuous Coking Process", Iron and Steel
Engineer, pp. 125-130 (September, 1973).
263
-------
69. Gordon, C.K. and Droughton, T.A., "Continuous Coking Process",
AISE, Chicago, Illinois (April, 1973).
70. Gould, J.P. and Weber, W.J,, Jr., "Oxidation of Phenols by
Ozone", Water Pollution Control Federation, Journal, £8(1), pp.
47-60 (January, 1976).
71. Grieve, C.G., Stenstron, M.K., "Powdered Carbon Improves
Activated Sludge Treatment, Hydrocarbon Processing, October,
1977.
72. Grosick, H.A., "Ammonia Disposal - Coke Plants", Blast Furnace
and Steel Plant, pp. 217-221 (April, 1971).
73. Haqer, D.G., "Waste Treatment Advances: Waste Water Treatment
Via Activated Carbon," Chemical Engineering Progress, 72 (10),
pp. 57-60 (October, 1976).
74. Hall, S.A., Brantner, K.A., Kubarewicz, J.W., Sullivan, M.D.,
"Pilot Evaluation of Alkaline Chlorination Alternatives for Blast
Furnace Treatment", presented at the U.S. EPA Symposium on Iron
and Steel Pollution Abatement Technology for 1981, October 1981.
75. Hall, D.A. and Nellis, G.R., "Phenolic Effluents Treatment,"
Chemical Trade Journal (Brit.), 156, p. 786 (1965).
76. Hansen, L.G., Oleson, K.A., "Comparison of Evaporative Losses in
Various Cooling Water Systems," American Power Conference, April
21-23, 1970.
77. Harold, D.S., "Development of a Deduing Process for Recycling
Millscale", Presented at the U.S. EPA Symposium on Iron and Steel
Pollution Abatement Technology, October 1981.
78. Hoffman, D.C., "Oxidation of Cyanides Adsorbed on Granular
Activated Carbon", Plating, 60, pp. 157-161 (February, 1973).
75. Hutton, W.C. and LaRocca, S.A., "Biological Treatment of
Concentrated Ammonia Wastewaters," Water Pollution Control
Federation, Journal, 47 (5), p. 989-997 (May, 1975).
80. lammartino, N.R., "Formed Coke: A 1980's Boom for the World's
Steelmakers?", Chemical Engineering, 83 (27), pp. 30-36
(December 20, 1976).
81. "Annual Review of Developments In The Iron and Steel Industry
During 1977," Iron and Steel Engineer, p. Dl (February, 1978).
82. Jola, M., "Destruction of Cyanides by the Cyan-Cat Process,"
Plating and Surface Finishing, pp. 42-44 (September, 1976).
26-1
-------
83. Kemmetmueller, R., "Dry Coke Quenching - Proved, Profitable,
Pollution - Free", Iron and Steel Engineer, pp. 71-78 (October,
1973). •
84. Kiang, ¥., "Liquid Waste Disposal System", Chemical Engineering j
Progress, 72 (1), pp. 71-77 (January, 1976). |
85. Kibbel, W.H., "Peroxide Treatment For Industrial Waste Problems", [
Industrial Water Engineering, pp. 6-11 (August/September, 1976). '
86. Kolflat, T.D., Aschoff, A.F., Baschiere, R.S., "Cooling Towers
Versus Cooling Ponds - A State of the Art Review", presented at
ANS meeting, San Francisco, California, November 4, 1977.
87. Kohlmann, H.J., Hot stein, H., "Minimizing Water Blow downs from
selected steel plant processes", presented at the U.S. EPA
Symposium on Iron and Steel Pollution Abatement Technology for
1981, October 1981.
88. Knopp, P.V., Gifchel, W.B., Zimpro, Inc., "Wastewater Treatment
with Powdered Activated Carbon Regenerated with Wet Air
Oxidation.", Purdue Industrial Waste Conference.
89. Kostenbader, Paul D., and Flecksteinet, John W., "Biological
Oxidation of Coke Plant Weak Ammonia Liquor", Water Pollution
Control Federation, Journal, 41. pp. 199-207 (February, 1969).
90. Kremen, S.S., "Reverse Osmosis Makes High Quality Water Now",
Environmental Science and Technology, 9_ (4), pp. 314- 318 (April,
1975).
91. Kreye, W.C., King, P.H. and Randall, C.W., "Biological Treatment
of High Thiosulfate Industrial Wastewater,"Proceedings o|_ the
28th Industrial Waste Conference. Purdue University, pp. 537-545
(1973).
92. Kreye, W.C., King, P.H. and Randall, C.W., "Kinetic Parameters
and Operation Problems in the Biological Oxidation of High
Thiosulfate Industrial Wastewaters", Proceedings of the 29th
Industrial Waste Conference. Purdue University, pp. 410-419
(1974).
93. Labine, R.A., "Unusual Refinery Unit Produces Phenol- Free
Wastewater", Chemical Engineering, 66, 17, 114 (1959).
94. Lanouette, K. H., "Heavy Metals Removal," Chemical Engineering,
October 17, 1977.
95. Lanyon, R. Lue-Hing, C. "Reduction of Wastes Discharged from
Steel Mills in Metropolitan Chicago through local ordinance
enforcement", Presented at the U.S. EPA SYmposium on Iron and
Steel Pollution abatement Technology for 1981, October 1981.
265
-------
96. Lawson, C.T., Hovious, J.C., "Realistic Performance Criteria for
Activated Carbon Treatment of Wastewater from the Manufacturer of
Organic Chemicals and Plastics", Union Carbide Corp., Feb. 14,
1977.
97. Laufhuette, D., "Hydrogen Sulfide/Ammonia Removal From Coke Oven
Gas", I^ronmaking Proceedings, The Metallurgical Society of
A.I.M.E.. Atlantic City, 33., pp. 142-155 (1974).
98. Linsky, B., Littlepage, J., Johannes, A., Nekooi, R. and
Lincoln, P., "Dry Coke Quenching, Air Pollution and Energy: a
Status Report", Journal of the Air Pollution Control Association,
25 (9), pp. 918-924 (September, 1975TT
99. Lisanti, A.F., "Ultrafiltration Oil Reclamation Process," Iron
and Steel Engineer, (March, 1977).
100. Ludberg, James E., and Nicks, Donald G., "Phenols and Thiocyanate
Removed from Coke Plant Effluents", Water and Sewage Worksf 116,
pp. 10-13 (November, 1969).
101. Makridakas, S., Wheelwright, S., "Interactive Forecasting,
Holden-Day Inc., San Francisco, Cal., 1978.
102. Maloy, J., "Developments in Cokemaking Plant", Proceedings of_
Coke in Ironmaking Conference, Iron and Steel Institute, London,
pp. 89-97 (December, 1969).
103. Marting, D.G. and Balch, G.E., "Charging Preheated Coal to Coke
Ovens", Blast Furnace and Steel Plant, p. 326 (May, 1970).
104. Maruyama, T. et al., "Metal Removed by Physical and Chemical
Treatment Process," Journal WPCF, Volume 47, No. 5, (May, 1975).
105. McBride, T.J. and Taylor, D.M., "Joint Municipal-Industrial
Wastewater Treatment Based on Pilot Plant Studies," Proceedings
of the 28th Industrial Waste Conference, Purdue University, pp.
832-840 (1973T
106. McKee, J.E. and Wolfe, H.W., "Water Quality Criteria", Second
Edition, State Water Quality Control Board, Sacramento,
California, Publication No. 3-A.
107. McManus, G.J., "Mini Mill Approaches Continuous Steelmaking",
Iron Age, 211 (16), pp. 62-63 (April 19, 1973).
108. McManus, G.J., "One-Step Steelmaking Takes Another Step Toward
Reality", Iron Age, p. 41 (May 10, 1973).
109. McManus, G.J., "U.S. Examines Soviet Dry Coke Quenching", Iron
Age, pp. 47-48 (May 31, 1973).
26G
-------
110. McMichael, Francis C., Maruhnich, Edward D., and Samples, William
R., "Recycle Water Quality From a Blast Furnace", Journal of the
Water Pollution Control Federation, £3, pp. 595-603 (19?"lT7
111. McMorris, C.E., "Inland's Experience in Reducing Cyanides and
Phenols in the Plant Water Outfall", Blast Furnace and Steel
Plant, pp. 43-47 (January, 1968).
112. McMorris, C.E., "Inland's Preheat - Pipeline Charged Coke Oven
Battery", Ironmaking Proceedings^ The Metallurgical Society of
A.I.M.E.. Toronto, pp. 330-338 (1975).
113. Medwith, B.W., Lefei Hoce, J.F., "Single-stage Biological
Treatment of Coke Plant Wastewaters with a Hybrid Suspended
Growth-fixed firm Reactor", presented at the 36th Purdue
Industrial Waste Conference, May 1981.
114. Minor, P.S., "Organic Chemical Industry's Waste Waters"
Environmental Science and Technology, § (7), pp. 620-625 (July,
1974).
115. "More Pollution Control", Iron Age, 217 (22), p. 11 (May 31,
1976).
116. Muller, J.M. and Coventry, F.L., "Disposal of Coke Plant Waste in
the Sanitary Water System," Blast Furnace and Steel Plant, pp.
400-406 (May, 1968).
117. Nasco, A.C. and Schroeder, J.W., "A New Method of Treating Coke
Plant Waste Waters", Ironmaking Proceedings, The Metallurgical
Society of A.I.M.E., Atlantic City. 33, pp. 121-141 (1974).
118. Nemec, F.A., "How Much Environmental Protection -What Should Be
The Federal Role?", Iron and Steel Engineer, 53 (10), pp. 35-37
(October, 1976).
119. Negmeth, R.L., Wxsniewski, L.D., "Minimizing Recycled Water
Slowdown from Blast Furnace Gas Cleaning Systems", presented at
the U.S. EPA Symposium on Iron and Steel Pollution Abatement
Technology for 1981, October 1981.
120, Nilles, P.E. and Dauby, P.H., "Control of the OBM/Q-BOP Process",
Iron and Steel Engineer, pp. 42-47 (March, 1976).
121. Osantowski, R., Geinpolos, A., Rollinger, G. "Physical/Chemical
Treatment of Coke Plant Wastewater", U.S. EPA 600/S2-ED-107
April 1981.
122. Patterson, J.W., et al, "Heavy Metal Treatment via Carbonate
Precipitation," 30th Ind. Wastes Conf., Purdue Univ., pg. 132
(May, 1975).
267
-------
123.
124.
125.
126.
127.
128.
129.
130.
131 .
132.
133.
134.
135.
136.
Patton, R.S., "Hooded Coke Quenching System For Air Quality
Control", Ironmakinq Proceedings, The Metallurgical Society of.
A.I.M.E. . Atlantic City, 33., pp. 209-219 (1974).
Pearce, A.S. and Punt, S.E., "Biological Treatment of Liquid
Toxic Wastes-Part 1", Effluent and Water Treatment Journal. 15,
pp. 32-39 (January, 1975T
Pearce, A.S. and Punt, S.E., "Biological Treatment of Liquid
Toxic Wastes-Conclusion," Effluent and Water Treatment Journal,
15, pp. 87-95 (February, 1975).
Pearce, J., "Q-BOP Facility Planning and Economics," Iron and
Steel Engineer, pp. 27-37 (March, 1976).
Pearce, J., "Q-BOP Steelmaking Developments,
Engineer, pp. 29-38 (February, 1975).
Iron and Steel
Pengidore, D.A., "Application of Deep Bed Filtration to Improve
Slab Caster Recirculated Spray Water", Iron and Steel Engineer,
52. (7), pp. 42-45 (July, 1975).
Perry, J.H., Chemical Engineering Handbook, 4th edition.
"Pollution Control at Inland, A Long, Hard, and Costly Climb", 33_
Magazine, Tj (6), pp. 80-81 (June, 1974).
Potter, N.M. and Hunt, J.W., "The Biological Treatment of Coke
Oven Effluents", Air and Water Pollution in the Iron and Steel
Industry, Special Report No^ 61, pp. 207-218 (1958).
Price, J.G., Berg, T.A. and Stratman, J., "Coke Oven Pushing
Emissions Control and Continuous Wet Coke Quenching," Ironmaking
Proceedings, The Metallurgical Society of A.I.M.E.T Atlantic
City. 33. pp. 220-232 (1974).
"Process Design Manual for Carbon
Technology Transfer, (October, 1973).
Adsorption," U.S. EPA
Raef, S.F., Characklis, W.G., Kessick, M.A. ami Ward, O.H., "Fate
of Cyanide and Related Compounds in Industrial Waste Treatment",
Proceedings of the 29th Industrial Waste Conference, Purdue
University, pp. 832-840 (1974).
Research on Dry Type Cooling Towers for Thermal Electric
Generation - Part I, Environmental Protection Agency,
16130EE511/70.
Rexnord, Inc., Environmental Research Center", Treatment of Steel
Plant Wastewaters to BATEA levels using Mobile Treatment Units",
prepared for U.S. EPA, Research Triangle Park, June 26,1979.
268
-------
136.
138.
139.
140.
141.
142.
143.
Rizzo, J.L., "Granular Carbon for Wastewater Treatment," Water
and Sewage Works, Volume 118, pp. 238-240, (April, 1971).
Rosfjord, R.E., Trattner, R.E. and Cheremisinoff, P.N., "Phenols
- A Water Pollution Control Assessment,"Water and Sewage Works,
123 (3), pp. 96-99 (March, 1976).
Rouse, J.V., "Removal of Heavy Metals from Industrial Effluents,"
Journal of the Environmental Engineering Division.., V 102, No.
EE5, (October, 1976).
Savage, E.S., "Deep-Bed Filtration of Steel Mill
Date of publication unknown.
Effluents."
Scott, Murray C., Sulfex (TM) - "A New Process Technology for the
Removal of Heavy Metals from Waste Streams - Presented at the
1977 Purdue Industrial Waste Conference, (May, 1977).
Scott, M.C., "Sulfide Process Removes Metals, Produces Disposable
Sludge,"Industrial Wastes - Pgs. 34-39, (July- August, 1979).
Skubak, J., NewfeJd, R.D., "A Mass Balance Model for Rinsewater
in 'a Continuous Strip Halogen Electrolytic Tinning Operation for
use in Evaluting Wastewater Treatment and Recovery Alternatives",
presented at the U.S. EPA Symposium on Iron and Steel Pollution
Abatement Technology for 1981, October 1981.
144. Smith, John M., Masse, A.N., Feige, W.A. and Kamphake, L.J.,
"Nitrogen Removal From Municipal Waste Water by Columnar
Denitrification", Environmental Science and Technology, 6, p.
260 (March 3, 1972T
145. "Coke in the Iron and Steel Industry New Methods in Conventional
Processes" Steel Times, 193, pp. 551-556 (October 21, 1966).
146. Sugeno, T., Shimokawa, K. and Tsuruoka, K., "Nuclear Steelmaking
in Japan", Iron and Steel Engineer, 53 (11), pp. 40- 47
(November, 1976).
147; Symons, C.R., "Treatment of Cold Mill Wastewater by Ultra-High
Rate Filtration," ."ournal of the Water Pollution Control
Federation. (November, 1971).
148. Technical and Economic Evaluation of Cooling Systems Slowdown
Control Technologies, Environmental Protection Agency, Office of
Research and Development, EPA-660/2-73-026.
149. Terril, M.E., Neufeld, R.D., "Investigation of Reverse Osmosis
for the Treatment of Recycled Blast-Furnace scrubber Water",
presented at the U.S. EPA Symposium ib Iron and Steel Pollution
Abatement Technology for 1981, October 1981.
A
1
269
-------
150. Traubert, P.M., "Weirton Steel Div. - Brown's Island Coke Plant",
Iron and Steel Engineer, 5_4 (1 ), pp. 61-64 (January, 1977).
151. U.S. Department of the Interior, "The Cost of Clean Water",
Volume III - Industrial Wastes, Profile No. K
152. United States Steel, The Making, Shaping, and Treating of_ Steel,
Harold E. McGannon ed., Harlicek and Hill, Pittsburgh, 9th
Edition, (1971).
«
153. Voelker, F.C., Jr., "A Contemporary Survey of Coke-Oven Air
Emissions Abatement", Iron and Steel Engineer, pp. 57-64
(February, 1975).
154. Voice, E.W. and Ridigion, J.M., "Changes In Ironmaking Technology
In Relation To the Availability of Coking Coals", Ironmaking and
Steelmakinq (Quarterly), pp. 2-7 (1974).
155. Wahl, J.R., Hayes, T.C., et al, "Ultra:iltration For Today's Oily
Wastewaters: A Survey of Current Ultrafiltration Systems."
Presented at the 34th Annual Purdue Industrial Waste Conference.
(May, 1979).
156. Wagener, D., "Characteristics of High - Capacity Coke Ovens",
Iron and Steel Engineer, pp. 35-41 (October, 1974).
157. Wallace, De Yarman, "Blast Furnace Gas Washer Water Recycle
System," Iron and Steel Engineer Yearbook, pp. 231-235 (1970).
158. "Waste Water Treatment Facility at U.S. Steel's Fairfield Works",
Iron and Steel Engineer, p. 65 (June, 1976). ,
159. "Weirton Steel Gets It All Together at New Coke Plant on Brown's I
Island," 33 Magazine, 11 (1), pp. 27-30 (January, 1973).
160. Wilson, L.W., Bucchianeri, B.A., Tracy, K.D., "Assessment of the
Biological Treatment of coke-Plant Wastewaters with addition of
Powdered Activated Carbon (PAC)", presented at the US.S EPA
Symposium on Iron and Steel Pollution Abatement Technology for
1/81, October 1981.
161. Woodson, R.D., "Cooling Towers," Scientific American. 224(5).
70-78, (May, 1971).
162. Woodson, R.D., "Cooling Alternatives for Power Plants," paper
presented to the Minnesota Pollution Control Agency, (November
30, 1972).
163. "World-Wide Oxygen Steelmaking Capacity - 1974", Iron and Steel
Engineer, p. 90 (April, 1975).
164. "Worldwide Oxygen Steelmaking Capacity - 1975", Iroj-i and Steel
Engineer, p. 89 (April, 1976).
27 C.
-------
165. "World Steel Statistics - 1975",
57-58 (August, 1976).
Iron and Steel Engineer pp.
166. Zabban, Walter and Jewett, H.W., "The Treatment of Fluoride
Wastes," Engineering Bu1 letin of Purdue University, Proceedings
of the 22nd Industrial Waste Conference, 196?, p. 706.
167. Zahka, Pinto, S.D., Abcor, Inc. Ultrafiltration of Cleaner Baths
Using Abcor Tuoular Membranes.
"M
V
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-'I
^3
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VOLUME I
APPENDIX A
STATISTICAL METHODOLOGY AND DATA ANALYSIS
Introduction
Statistical Methodology
This section1 provides an overview of the statistical methodology used
by the Agency to develop effluent limitations for the steel industry.
The methodology consists essentially of determining long term average
pollutant discharges expected fro® well designed and operated
treatment systems, and multiplying these long term averages by
variability factors designed to allow for random fluctuations in
treatment system performance. The resulting products yield daily
maximum and 30-day average concentrations for each pollutant. The
daily maximum and 30-day average concentrations were then multipled by
an appropriate conversion factor and the respective treatment system
model effluent flow rate to determine mass limitations. A general
description of the methods employed to derive long term averages,
variability factors, and the resulting concentrations follows. The
development of the model treatment system flow rates are presented in
each subcategory report.
Determination of Long Term Average
For each wastewater treatment facility, an average pollutant
concentration was calculated from the daily observations. The median
of the plant averages for a pollutant was then used as the long term
average for the industry. The long term average was determined for
each pollutant to be limited and used to obtain the corresponding
limitations for that pollutant.
The long term average (LTA) is defined as the expected discharge
concentration (in mg/1) of a pollutant from a well designed,
maintained, and operated treatment system. The long-term average is
not a limitation, but rather a design value which the treatment system
should be designed to attain over the long term.
Determination of Variability Factors
Fluctuations in the pollutant concentrations discharged occur at well
designed and properly operated treatment systems. These fluctuations
may reflect temporary imbalances in the treatment systes caused by
fluctuations in flow, raw waste load of a particular pollutant,
chemical feed, mixing flows within tanks, or a variety of other
factors.
273
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Allowance for the day-to-day variability in the concentration of a
pollutant discharged from a well designed and operated treatment
system is accounted for in the standards by the use of a "variability
factor." Under certain assumptions discussed below, application of a
variability factor allows the calculation of an upper bound for the
concentration of a particular pollutant. On the average a specified
percent of the randomly observed daily values from treatment systems
discharging this pollutant at a known mean concentration would be
expected to fall below this bound. The 99th percentile for the daily
maximum value is a commonly used and accepted level in the steel and
other industrial categories. Also, this percentile has been chosen to
provide a balance between appropriate considerations of day-to-day
variation in a properly operating plant and the necessity to insure
that a plant is operating properly.
The derivation of the variability factor for plants with more than 10
but less than 100 observations is based upon the assumption that the
daily pollutant concentrations follow a lognormal distribution. This
assumption is supported by plots of the empirical distribution
function of observed concentrations for various pollutants (Figures
A-l to A-4). The plots of these data on lognormal probability paper
approximated straight lines as would be expected of data that is
lognormally distributed. It is also assumed that monitoring at a
given plant was conducted responsibly and in such a way that resulting
measurements can be considered independent and amenable to standard
statistical procedures. A final assumption is that treatment
facilities and monitoring techniques had remained substantially
constant throughout the monitoring period.
The daily maximum variability factor is estimated by the equation
(derived in Appendix XII-A1 of the Development Document for
Electroplating Pretreatment Standards, EPA 440/1-79/003, August,
1979),
In (VF) * Z(Sigma) - .5(Sigma)z (1)
where
VF is the variability factor
Z is 2.33, which is the 99th percentile for the standard normal
distribution, and
Sigma is the standard deviation of the natural logarithm of the
concentrations.
For plants with 100 or more observations for a pollutant, there are
enough data to use nonparametric statistics to calculate the daily
maximum variability factor. For these cases, the variability factor
was calculated by dividing the empirical 99th percentile by the
pollutant average. The empirical 99th percentile is that observation
whose percentile is nearest 0.99.
274
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The estimated single-day variability factor for each pollutant
discharged from a well designed and operated plant was calculated in
the following manner:
1. For each plant with 10 or more but less than TOO observations,
Sigma was calculated according to the standard statistical
formula14and was then substituted into Equation (1) to find the
VF.
2. For those plants with over 100 observations, the VF was estimated
directly by dividing the 99th percentile of the observed sample
values by their average.
3. The medir.n of the plant variability factors was then calculated
for each pollutant.
The variability factor for the average of a random sample of 30 daily
observations about the mean value of a pollutant discharged from a
well designed and operated treatment system was obtained by use of the
Central Limit Theorem. This theorem states that the average of a
sufficiently large sample of independent and identically distributed
observations from any of a large class of population distributions
will be approximately normally distributed. This approximation
improves as the size of the sample, n, increases. It is generally
accepted that a sample size of 25 or 30 is sufficient for the normal
distribution to adequately approximate the distribution of the sample
average. For many populations, sample sizes as small as 10 to 15 are
sufficient.
The 30-day average variability factor, VF*, allows the calculation of
an upper bound for the concentration of a particular pollutant. Under
the same assumptions stated above, it would be expected that 95
percent of the randomly observed 30-day average values from a
treatment system discharging the pollutant at a known mean
concentration will fall below this bound. Thus, a well operated plant
would be expected, on the average, to incur approximately one
violation of the 30-day average limitation during a 20 month period.
The 95th percentile was chosen in a manner analogous to that explained
previously in the discussion of the daily variability factor.
»ME(xi - x)*/(n-l )]»'*
where
x_i is the In of observation i
x is the average of observations
n is the number of observations
275
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The 30-day average variability factor was estimated by the following
equation (based on the Central Limit Theorem and previous
assumptions),
(VF*> « 1.0 * 7. (S*/A) (2)
where
VF* is the 30-day average variability factor;
Z is 1.64, which is the 95th percentile of the standard normal
distribution;
S* is the estimated standard deviation of the 30-day averages,
obtained by dividing the estimated standard deviation of the
daily pollutant concentrations by the square root of 30;
and,
A is the average pollutant concentration.
In the case of biological treatment of cokemaking wastewaters, the
Agency determined that , the general assumption of statistical
independence between successive observations, which is a basis "of the
general formula, is not valid. The other assumptions underlying the
application of the Central Limits Theorem valid. An analysis of the
data for the biological treatment system at Plant 0868A indicated that
sample measurements made over a number of succesive days are not
independent. As a result, the Agency modified its method for
calculating the 30-day average concentrations to account for this
correlation. It should bo noted that the Agency did not find
correlations of any significance between successive sample
measurements made at physical-chemical treatment systems used to treat
other steel industry wastewaters.
The application of the Central Limit Theorem to the effluent data from
biological treatment of cokemaking wastewaters remains valid. Thus,
the variability factors, VF*, for the 30-day average concentrations
are calculated using equation (2) above. However, to account for the
statistical dependence of the effluent data, the correlation
(Covariance) terms are included in the calculation of the standard
deviation of the 30-day averages, S*, as shown in Table A-51.
The effect of the dependency of the effluent data is to increase the
standard deviation, and, thus, increase the 30-day average
concentrations. The 30-day average concentration bases for total
suspended solids, ammonia-N and total cyanide for the BAT (biological)
limitations and NSPS for the cokemaking subcategory were calculated on
this basis. The phenols (4AAP) concentration was determined using the
original method since the Agency determined that the dependency of the
effluent data for phenols (4AAP) are not significant.
276
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Determination of Limitations
Daily maximum and 30-day average concentrations (L and L*,
respectively) were calculated for each pollutant from the long term
average (LTA), the daily variability factor (VF), and the 30-day
average variability factor (VF*) for that polluant by the following
equations:
L - VF X LTA (3)
L* « VF* x LTA (4)
The above concentrations were multiplied by the effluent flow
(gal/ton) developed for each treatment subcategory and an appropriate
conversion factor to obtain mass limitations and standards in units of
kg/1,000 kg of product.
The daily maximum limitation calculated for each pollutant is a value
which is not to be exceeded on any one day by a plant discharging that
pollutant. The 30-day average maximum limitation is a value which is
not to be exceeded by the average of up to 30 consecutive single-day
observations for the regulated pollutant. Long term data analyses are
presented in Tables A-2 through A-50.
Analysis of Data From Filtration and Clarification Treatment Systems
The observations used to derive daily maximum and 30-day average con-
centrations include both long term data obtained from the D-DCPs and \
agency requests, and short term data obtained through sampling visits.
Engineering judgment15 was used to delete 'some data from the long term
data sets analyzed;. Generally those data deleted indicate possible
upsets, lack of proper operation of treatment facilities, or bypasses.
These values typically could be considered effluent violations under
the NPDES permit system. The number of observations deleted for each
pollutant is identified in Tables A-9 to A-50. Table A-l presents a
key to the long-term data summaries for all plants included in the
analyses. A discussion of the analyses for filtration and for
clarification treatment systems follows.
Filtration Treatment System
Table A-2 presents average concentrations and variability factors for
total suspended solids for those plants1* with long term effluent data
for filtration treatment systems. Detailed descriptive statistics for
all relevant pollutants sampled at these plants are presented in
15The Agency's justification for using engineering judgment to delete
values from monitoring data sets was upheld in U.S. Steel Corp. v.
Train, 556 F.2d 822 (7th Cir. 1977).
16Plant 920N was not included in this long term data analysis. Visits
to this plant by EPA personnel have demonstrated that the treatment
system was not properly operated. j
277
-------
Tables A-9 to A-18. The median of the long term averages is
multiplied by the apporpriate median variability factor to obtain the
daily maximum and 30-day average concentrations for TSS as presented
in Table A-2. Table A-3 presents, in a similar manner, averages,
variability factors and daily maximum and 30-day average con-
centations for oil and grease.
The average concentrations for five toxic metals (chromium, copper,
lead, nickel and zinc) calculated from long and short term data are
presented with the respective medians in Table A-4. Variability
factors, presented in Table A-5, were calculated for those plants
having long term toxic metals data. The median daily maximum
variability factors for the metals range "from 2.0 to 4.5 and the
30-day variability factor for all of the toxic metals is 1.2. These
values are similar to those obtained for TSS and oil and grease, in
which case the daily maximum variability factors are 3.9 and 4.2 for
TSS, and oil and grease, respectively; and the 30-day average
variability factor is 1.3 for both pollutants. Since these
variability factors were calculated from a larger data base, the
Agency decided to use the average of these to represent the
variability of the toxic metals. Therefore, variability factors of
4.0 and 1.3 were used to obtain the daily maximum and 30-day average
concentrations, respectively. The results are presented in Table A-5.
The daily maximum and 30-day average concentrations were rounded up to
0.3 and 0.1 mg/1, respectively, for all toxic metals except zinc. For
zinc the daily maximum and 30-day average concentrations were rounded
to 0.45 and 0.15 mg/1, respectively. These values were used to
calculate the toxic metals mass limitations for filtration systems,
where applicable.
Clarification/Sedimentation Treatment System
Tables A-6 and A-7 present the average concentrations of long term
data, the variability factors and the calculations used to derive the
daily maximum and 30-day average concentrations for TSS and oil and
grease, respectively. The long term effluent data and the resultant
concentrations apply to clarifacation/sedimentation wastewater
treatment systems. Detailed descriptive statistics of these plants
are presented in Tables A-18 to A-37 and A-50. For Plants 0112,
0684F, and 0684H, long term data were provided for several parallel
treatment systems in one central treatment facility. In these
situations the data from the clarifier providing the best treatment
were used.
Screening and verification data were used to calculate the average
concentrations for toxic metals removal by clarification treatment
systems treating wastewaters from carbon steel operations. These |
average concentrations are presented in Table A-8. Variability ]
factors of 3.0 and 1.2 were used to calculate the daily maximum and ]
30-day average concentrations (shown in Table A-8), respectively, for j
all the metals. The above variability factors were based upon: j
270
-------
1. the variability factors for TSS and oil and grease in Tables A-6
and A-7; and,
2. the variability factors17 derived from toxic metals discharged
from clarification treatment systems in .the electroplating
category.
The daily maximum and 30-day average concentrations were rounded to
0.3 and 0.1 mg/1, respectively for chromium, copper, and zinc, and
0.45 and 0.2 mg/i for nickel, and 0.30 and 0.15 mg/1 for lead. These
concentrations were used to establish the toxic metals mass
limitations for all forming and finishing operations, with the
exception of combination acid pickling and salt bath descaling
operations.
For combination acid pickling and salt bath descaling operations, both
of which process speciality steels, the Agency relied on long term
effluent data from a clarification treatment facility located at Plant
0060B. This treatment facility treated wastewaters from both of these
specialty steel operations. The descriptive statistical data are
presented in Table A-34. The daily maximum and the 30-day average
concentrations used to establish the mass effluent limitations for
chromium are 1.0 mg/1 and 0.4 mg/1, respectively; and for nickel 0.7
mg/1 and 0.3 mg/1, respectively.
17Daily maximum variability factors presented in the "Development
Document for Electro- plating Pretreatment Standards"; are: Cu - 3.2,
Cr - 3.9, Ni - 2.9, Zn - 3.0, Pb - 2.9.
279
-------
TABLE A-l
KEY TO LONG-TERM DATA SUMMARIES
IRON & STEEL INDUSTRY
Table No.
A-9
A-10
A-ll
A-U
A-l 3
A-14
A-l 5
A-16
A-l 7
A-18
A-19
A-20
A-21
A-22
A-23
A-24
t 25
,.-26
A-27
A-28
A-29
A-30
A-31
A-32
A-33
A-34
A-35
A-36
A-37
A-38
A-39
A-40
A-41
A-42
A-43
A-44
A-45
A-46
A-47
A-48
A-49
A-50
Reference Code
0112B-SA
0112C-011
0112C-122
0112C-334
OU2C-617
OU2I-5A
0384A-JE
0384A-4L
0684H-EF
06B4F-4I
0112-5B
0112A-5A
0112H-5A
0320-5A
0384A-5E
0384A-5F
0584A-5F
0584B-5F
0684F-5B
0684F-5E
0684H-5C
0856N-5B
0860B
0920C->A
0060B
0060B
0860B
0584E
0856D
08603
0012A-5F
0060A
0868A
0684 F
0684 F
0060
0060
0060
06)2
0612
0612
0948C
Subcategory
Treatment
Hoi Fonsing
Hoi Forming
Hot Forming
Hoi Forming
Hoi Forming
Pickling/Al. Cleaning
Cent. Casting
Conl. Casting
Pipe & Tube
Hoi Forming
Ironmaking
Sintering
Comb. Acid Pickling
Hot Forming
Ironmaking
Steelmaking (BOF)
Hot Forming
Hot Forming
Ironmaking
Ironmaking
Ironmaking
Hot Forming
Ironmaking
Cold Rolling
Comb. Acid Pickling
Comb. Acid Pickling
Forming & Finishing
Mile. Finishing Operations
Forming & Finishing
Ironmaking
CokemaUing
Cokemaking
Cokemaking
Cokemaking
Cold Rolling
Sintering
Sintering
Sintering
Steelmaking - EAF
Sleelmaking - EAF
Steelmaking - EAF
Misc. Finishing Operations
Filtration
Filtration
Filtration
Filtration
Filtration
Filtration
Filtration
Filtration
Filtration
Lagoons/Filtration
Polymer/Clarifier
Thickener
C1arifier/Lagoons
Lagoona
Thickener
Thickener/Clarifier
Settling Basin
Lagoons
Clarifier
Clarifier
Clarifier
Settling Basin
Clarifier
Clarifier
Lirae/Lagoons
Lioe/Clarifier
Chem. Addition/Clarifiers
Chem. Addition/Clarifiers
Chem. Addition/Clarifiers
A. Chlorination/Filtration
Single-Stage Biological
Single-stage Biological
2-Slage Biological
Phys-Chem (Carbon Columns)
Cat Flotation
Filtration (Pilot)
Lime/Clarifier (Pilot)
Lime/Clar/Filter (Pilot)
Filter (Pilot)
Hydroxide/Clarifier (Pilot)
Lime/Filter (Pilot)
Chem. Addition/Clarifierfc
2CO
-------
TABLE A-2
LONG-TERM DATA ANALYSIS
FILTRATION SYSTEMS
TOTAL SUSPENDED SOLIDS
Plata
0112C-33A
0112I-5A
0112C-617
0684H-EF
OI12C-01I
0112B-5A
0384A-4L
0112C-122
0384A-3E
0684F-4I
Average (pg/1)
2.3
3.6
4.8
6.0
8.9
10.6
10.8
13.3
17.4
22.2
Variability Factor*
rage Maxioua*
1.4
1.5
1.3
1.3
1.3
1.1
1.3
1.3
1.2
1.2
Median Value* 9.8 1.3
30-Day Average Concentration Baei* • (9.8 mg/1) (1.3) • 12.7 ng/l
Daily MaxiouB Concentration Ba«it • (9.8 ag/1) (3.9) " 38.2 ag/1
Note: For the purpoae* of developing effluent limitation* and itandarda,
the following value* were uaed for total *u*pended tolid*.
Average -15 «g/l
Maxima* - 40 og/l
* For plant* with »ore than 100 observational
99th Percentile
Daily Variability Factor •
Average
281
6.8
8.9
5.4
5.3
3.5
2.3
3.0
4.0
2.5
3.7
3.9
-------
TABU A-3
LONG-TERM DATA ANALYSIS
FILTRATION SYSTEMS
Oil. AND CIEASE
Plant
0112B-SA
0112C-334
0112C-617
0112C-122
0684H-EF
0112C-OI1
0384A-4L
Average (•>/!)
1.1
1.3
1.3
2.0
3.4
6.7
6.7
Variability Pactora
raee Maxinua*
1.1
1.4
1.4
1.3
1.4
1.3
1.2
2.9
5.3
4.5
5.3
3.8
5.1
3.4
Median Value* 2.0 1.3
30-Day Avtt«|« Concentration Kati* • (2.0 •»/!) (1.3) » 2.6 •»/!
Daily Haxi«m Conccntratioa B««i* • (2.0 aj/l) (4.5) • 9.0 •»/!
4.5
Not*: A atxiaua valu* of 10 •»/! haa been u»«d to develop
effluent liatitatioa* and atandardi for oil and greaae.
* For planta with more than 100 obaervatiooat
99th Percentile
Daily Variability Factor •
Average
2C2
-------
TABLE A-4
DATA ANALYSIS
FILTRATION SYSTEMS
RECgLATED METALLIC POLLUTANTS
PUnt
A. Chroaiu*
OI12I-5A
0684 F-41
0684H
0584E
0496
0612
MEDIAN
NIB her of
ple Pointi
61
II
3
3
3
3
Average
(mg/1)
0.02
0.03
0.03
0.03
0.03
0.04
0.03
B. Copper
0584F
0684 F-41
0684H
0612
0496
0112I-5A
08688
MEDIAN
3
11
3
3
3
60
3
0.015
0.02
0.02
0.03
0.05
O.OS
0.25
•-.03
C. U«d
0684P-4I
0684H
0496
01121
0612
0868B
MEDIAN
11
3
3
3
3
3
0.03
0.05
0.05
0.07
0.18
0.32
0.06
-------
TABLE A-4
DATA ANALYSIS
PILTKATION SYSTEMS
RCGDLATCD METALLIC POLLOUURS
PACE 2
ef
0684 H
0612
0496
OU2I-5A
0684F-*I
3
3
3
27
11
MEDIAN
0.02
0.025
O.C4
0.07
0.09
O.Oi
E. line
06&4H
OSME
0496
0112I-5A
0612
0684 P
0868B
3
3
3
>8
3
43
3
MEDIAN
0.02
0.02
0.02
0.10
0.12
0.39
1.6
0.10
2S4
-------
TA»t* A-5
DERIVATION Of VARIABILITY FACTORS AlfO PROPOSED LIMITS
FILTRATION SYSTEMS
REGULATED MBTALLIC POLLUTANTS
Parameter
A. Qiromivam
0112I-SA
0684F-*I
MEDIAN
B. Copper
0112I-5A
0684 f-4 1
MEDIAN
C.
0684 F-* I
ibility Fcetor*
No. of
Staple Point*
61
a
60
tl
n
27
11
58
45
Averai
1.2
1.2
1.2
1.2
1.1
1.2
1.1
1.2
1.2
1.2
1.2
1.2
Variability Factor*
t* MaitiwJ*
2.9
3.6
3.3
5.1
2.7
3.9
2.0
3.3
5.6
4.5
3.0
4.2
D. Nicktl
0112I-5A
06S4F-4I
MEDIAN
E. Zinc
01..T-5A
U684P-4I
VDIAN
Hotct n** for «ll regulated cietal*
A»«r*gc Variability Factor • 1.3
Kaxiamai Variability Factor • 4.0
1.2
3.6
285
\