Lawrence K Wang and Nazih K Shammas

CONTENTS

7.1 General Description of Coil Coating Industry and Operations 260

7.2 Cleaning Operation of Coil Coating 261

7.2.1 Mild Alkaline Cleaning 261

7.2.2 Strong Alkaline Cleaning 262

7.2.3 Acid Cleaning 262

7.2.4 Special Cleaning 262

7.3 Conversion Coating Process of Coil Coating 262

7.3.1 Chromate Conversion Coatings 263

7.3.2 Phosphate Conversion Coatings 263

7.3.3 Complex Oxide Conversion Coating 264

7.3.4 No-Rinse Conversion Coatings 264

7.4 Painting Operation of Coil Coating 265

7.5 Subcategories of the Coil Coating Industry 265

7.5.1 General Description of Subcategorization 265

7.5.2 Coil Coating on Steel Subcategory 266

7.5.3 Coil Coating on Zinc Coated Steel

(Galvanized Steel) Subcategory 266

7.5.4 Coil Coating on Aluminum Subcategory 267

7.6 Wastewater Characterization of the Coil Coating Industry 267

7.6.1 Effluent Characteristics of Coil Coating on Steel Operation 267

7.6.2 Effluent Characteristics of Coil Coating on Zinc Coated Steel

(Galvanized Steel) Operation 267

7.6.3 Effluent Characteristics of Coil Coating on Aluminum Operation 275

7.7 Plant-Specific Effluent Characterization Data 276

7.7.1 Plant A: Coating Cold Rolled Steel and Galvanized Steel 277

7.7.2 Plant B: Coating Both Cold Rolled Steel and Galvanized Steel 277

7.7.3 Plant C: Coating Aluminum and Other Metals 277

7.8 Coil Coating Effluent Treatment Technologies 278

7.8.1 Ion Exchange 279

7.8.2 Electrochemical Chromium Regeneration 280

7.8.3 Oil Skimming 280

7.8.4 Chromium Reduction and Chemical Precipitation 280

7.8.5 Cyanide Destruction 281

7.8.6 Oil-Water Separation, Biological Treatment,

Powdered Activated Carbon Adsorption, and Clarification 281

7.8.7 Granular Bed Filtration and Granular Activated Carbon Filtration 282

7.8.8 Membrane Processes 284

7.8.9 Other Water-Solids Separation Technologies 284

7.8.10 Full-Scale Wastewater Treatment Case History:

Steel Subcategory 287

7.8.11 Full-Scale Wastewater Treatment Case History:

Galvanized Subcategory 289

7.8.12 Full-Scale Wastewater Treatment Case History:

Aluminum Subcategory 290

7.9 Wastewater Treatment Levels Versus Costs 291

7.9.1 BPT Level Treatment 291

7.9.2 BAT Level of Treatment 292

7.10 Multimedia Waste Management in the Coil Coating Industry 292

7.10.1 Air Pollution Control 292

7.10.2 Water Pollution Control 293

7.10.3 Solid and Hazardous Wastes Management and Disposal 294

7.10.4 Waste Minimization and Cleaner Production Alternatives for

Roll and Coil Coating 294

7.11 Coil Coating Industry Liquid Effluent Limitations,

Performance Standards, and Pretreatment Standards 295

7.11.1 Effluent Limitations, Performance Standards, and

Pretreatment Standards of the Steel Basis Material Subcategory 295

7.11.2 Effluent Limitations and Performance Standards of the

Galvanized Basis Material Subcategory 296

7.11.3 Effluent Limitations and Performance Standards of the

Aluminum Basis Material Subcategory 298

7.11.4 Effluent Limitations, Performance Standards, and

Pretreatment Standards of Canmaking Subcategory 300

7.12 Technical Terminologies of Coil Coating Operations and Pollution Control 302

References 304

7.1 GENERAL DESCRIPTION OF COIL COATING INDUSTRY AND OPERATIONS

The U.S. coil coating industry consists of about 80 plants processing approximately 1.5 billion square meters of painted coil each year. Facilities vary in size and corporate structure, ranging from independent shops to captive operations. Independent shops obtain untreated coil, conversion coating chemicals, and paints, and produce a wide variety of coated coil. Typically, the annual production at these coil coating plants is low compared to that from the captive coating operations. The captive coil coating operation is usually an integral part of a large corporation engaged in many other kinds of metal production and finishing.

The coil coating sequence, regardless of basis material or conversion coating process used, consists of three operational steps:

1. Cleaning

2. Conversion coating

3. Painting

There are three types of cleaning operations used in coil coating, and they can be used alone or in combination. These cleaning operations are as follows:

1. Mild alkaline cleaning

2. Strong alkaline cleaning

3. Acid cleaning

There are four basic types of conversion coating operations, and the use of one precludes the use of the others on the same coil:

1. Chromating

2. Phosphating

3. Use of complex oxides

4. No-rinse conversion coating

Some of these conversion coating operations are designed for use on specific basis materials. The painting operation is performed by roll coating and is independent of the basis material and conversion coating. Some specialized coatings are supplied without conversion-coating the basis material. For example, Zincrometal is a specialized coating consisting of two coats of special paints that do not require conversion coating. In this process, coils are cleaned and dried, and then receive two coats of the special paints.

The selection of basis material, conversion coating, and paint formulation is an art based upon experience. The variables that are typically involved in the selection are appearance, color, gloss, corrosion resistance, abrasion resistance, process line capability, availability of raw materials, customer preference, and cost. Some basis materials inherently work better with certain conversion coatings, and some conversion coatings work better with certain paint formulations. On the whole, however, the choice of which combination to use on a basis material is limited only by plant and customer preferences.1-4

The following subsections describe the coil coating processes in more detail.

7.2 CLEANING OPERATION OF COIL COATING

Coil coating requires that the basis material be clean. A thoroughly clean coil ensures efficient conversion coating and a resulting uniform surface for painting. The soils, oils, and oxide coatings found on a typical coil originate from rolling mill operations and storage conditions prior to coil coating. Such substances can stop the conversion coating reaction, cause a coating void on part of the basis material, and result in the production of a nonuniform coating. Cleaning operations must chemically and physically remove these interfering substances without degrading the surface of the basis material. Excessive cleaning can roughen a basically smooth surface to a point where a paint film will not provide optimum protective properties.

7.2.1 Mild Alkaline Cleaning

Aluminum and galvanized steel are prone to develop an oxide coating that acts as a barrier to chemical conversion coatings. However, these oxide films are easier to remove than rust and, therefore, require a less vigorous cleaning process. A mild alkaline cleaner is usually applied with power spray equipment to remove the oxide coating and other interfering substances. The cleaning solutions normally used consist of combinations of sodium carbonates, phosphates, silicates, and hydroxides. These compounds give the solution its alkaline character and emulsify the removed soils. Soap and detergents may be added to the solution to lower the surface and interfacial tension.

7.2.2 Strong Alkaline Cleaning

A good cleaning solution also rinses easily. Solutions may be made stronger with the addition of more sodium hydroxide.

A spray rinse follows either the mild alkaline cleaning step or strong alkaline cleaning step. Spray rinsing is conducive to the fast line speeds that make coil coating an economical coating procedure. The spray rinse physically removes alkaline cleaning residues and soil by both the physical impingement of the water and the diluting action of the water. The rinsewater is usually maintained at approximately 66°C (150°F) to keep the coil warm for the subsequent conversion coating reactions and to help the rinsing action. The rinsing action prevents contamination of the conversion coating bath with cleaning residues that are dragged out on the strip and that could be subsequently deposited in the conversion coating solutions. The rinsing step also keeps the surface of the metal wet and active, which permits faster conversion coating film formation.

7.2.3 Acid Cleaning

Steel, unless adequately protected with a film of oil subsequent to rolling mill operations, has a tendency to form surface rust rather quickly. This rust on the surface of the metal prevents proper conversion coating. A traditional method of removing rust is an acid applied by power spray equipment. The spraying action cleans both by physical impingement and the etching action of the acid. The power spray action is followed by a brush scrub, which further removes soil loosened by the acid. The brush scrub is followed by a strong alkaline spray wash, which removes all traces of the acid and neutralizes the surface.1-5

7.2.4 Special Cleaning

The no-rinse conversion coating and the Zincrometal processes require a coil that is clean, warm, and dry. For these processes a squeegee roll and forced air drying are used to assure a clean, dry coil following alkaline cleaning and rinsing.

7.3 CONVERSION COATING PROCESS OF COIL COATING

The basic objective of the conversion coating process is to provide a corrosion-resistant film that is integrally bonded chemically and physically to the base metal and that provides a smooth and chemically inert surface for subsequent application of a variety of paint films. The conversion coating processes effectively render the surface of the basis material electrically neutral and immune to galvanic corrosion. Conversion coating on basis material coils does not involve the use of applied electric current to coat the basis material. The coating mechanisms are chemical reactions that occur between solution and basis material.1-4

Four types of conversion coatings are normally used in coil coating:

1. Chromate conversion coatings

2. Phosphate conversion coatings

3. Complex oxides conversion coatings

4. No-rinse conversion coatings

Chromate conversion coatings, phosphate conversion coatings, and complex oxide conversion coatings are applied in basically the same manner. No-rinse conversion coatings are roll applied and use quite different chemical solutions than phosphating, chromating, or complex oxides solutions. However, the dried film is used as basis for paint application similar to phosphating, chromating, and complex oxide conversion coating films.

7.3.1 Chromate Conversion Coatings

Chromate conversion coatings can be applied to both aluminum and galvanized surfaces but are generally applied only to aluminum surfaces. These coatings produce an amorphous layer of chromium chromate complexes and aluminum ions. The coatings offer unusually good corrosion-inhibiting properties but are not as abrasion resistant as phosphate coatings. Scratched or abraded films retain a great deal of protective value because the hexavalent chromium content of the film is slowly leached by moisture, providing a self-healing effect. Under limited applications, these coatings can serve as the finished surface without being painted. If further finishing is required, it is necessary to select an organic finishing system that has good adhesive properties. Chromate conversion coatings are extremely smooth, electrically neutral, and quite resistant to chemical attack.

Chromate conversion coatings for aluminum are carried out in acidic solutions. These solutions usually contain one chromium salt, such as sodium chromate or chromic acid and a strong oxidizing agent such as hydrofluoric acid or nitric acid. The final film usually contains both products and reactants and water of hydration. Chromate films are formed by the chemical reaction of hexavalent chromium with a metal surface in the presence of "accelerators" such as cyanides, acetates, formates, sulfates, chlorides, fluorides, nitrates, phosphates, and sulfamates.

Chromate conversion coating requires that the basis material be alkaline-cleaned and spray-rinsed with warm water. The cleaning and rinsing assures a clean, warm, wet surface on which the conversion coating process takes place. Once the film is formed, it is rinsed with water followed by a chromic acid sealing rinse. This latter rinse seals the free pore area of the coating by forming a chromium chromate gel. Also, the sealing rinse more thoroughly removes precipitated deposits that may have been formed by hard water in previous operations. The coil is then subjected to a forced air drying step to assure a uniformly dry surface for the following painting operation.

7.3.2 Phosphate Conversion Coatings

Phosphate conversion coatings provide a highly crystalline, electrically neutral bond between a base metal and paint film. The most widespread use of phosphate coatings is to prolong the useful life of paint finishes. Phosphate coatings are primarily used on steel and galvanized surfaces but can also be applied to aluminum. Basically, there are three types of phosphate coatings:

1. Iron phosphate coating

2. Zinc phosphate coating

3. Manganese phosphate coating

Manganese phosphate coatings are not used in coil coating operations because they are relatively slow in forming and, as such, are not amenable to the high production speeds of coil coaters.

The remaining two phosphate coatings are applied by spraying or immersing the coil, with the major difference between them being the weight and thickness of the dried coating. Iron phosphate coatings are the thinnest and lightest and generally the cheapest. Iron phosphate solutions are applied chiefly as a base for paint films. Spray application of iron phosphating solutions is most commonly used. The coating weights range from 0.22 to 0.86 g/m2.

Zinc phosphate coatings are quite versatile and can be used as a base for paint or oil, as an aid to cold forming, to increase wear resistance, and to provide rust-proofing. Zinc phosphate coatings can be applied by spray or immersion, with applied coating weights ranging from 1.08 to 10.8 g/m2 for spray coating and from 1.61 to 43.1 g/m2 for immersion coating.

Phosphate coatings are formed in the metal surface, incorporating metal ions dissolved from the surface. This creates a coating that is integrally bonded to the base metal. In this respect, phosphate coatings differ from electrodeposited coatings, which are superimposed on the metal. Most metal phosphates are insoluble in water but soluble in mineral acids. Phosphating solutions consist of metal phosphates dissolved in carefully balanced solutions of phosphoric acid. As long as the acid concentration of the bath remains above a critical point, the metal ions remain in solution. Accelerators speed up film formation and prevent the polarization effect of hydrogen on the surface of the metal. The accelerators commonly used include nitrites, nitrates, chlorates, and peroxides. Cobalt and nickel nitrite accelerators are the most widely used and develop a coarse crystalline structure. The peroxides are relatively unstable and difficult to control, whereas chlorate accelerators generate a fine sludge that may cause dusty or powdery deposits.

After phosphating, the coil is passed through a recirculating hot water spray rinse. The rinsing action removes excess acid and unreacted products, thereby stopping the conversion coating reaction. Insufficient rinsing could cause blistering under the subsequent paint film from the galvanic action of the residual acid and metal salts.

The basis material is then passed through an acid sealing rinse comprising up to 0.1% by volume of phosphoric acid, chromic acid, and various metallic conditioning agents, notably zinc. This solution seals the free pore area of the coating by forming a chromium chromate gel. Also, this acidic sealing rinse more thoroughly removes precipitated deposits formed by hard water in the previous rinses. Modified chromic acid rinses have been used extensively in the industry. These rinses are prepared by reducing chromic acid with an organic reductant to form a mixture of trivalent chromium and hexavalent chromium in the form of a complex chromium chromate.

7.3.3 Complex Oxide Conversion Coating

Complex oxide conversion coatings can be applied to aluminum and galvanized surfaces but are generally applied to only galvanized surfaces. The nature of the film and the chemical and physical actions of its formation are a function and a reinforcement of the naturally occurring protective oxide coating that is found on galvanized surfaces. The physical properties of the complex oxide conversion coating film are comparable to those of chromate conversion coating films and phosphate conversion coating films.

Complex oxide film is formed in a basic solution, whereas the films described earlier are formed in an acidic solution. Complex oxide conversion coating reactions do not contain either hexavalent or trivalent chromium ions. However, the sealing rinse contains much greater quantities of hexava-lent and trivalent chromium ions than do the sealing rinses associated with phosphate conversion coatings and chromate conversion coatings.

7.3.4 No-Rinse Conversion Coatings

Recent developments in chromate conversion coating solutions have resulted in a solution that can be applied to cold rolled steel, galvanized steel, or aluminum without the need for any rinsing after the coating has formed on the basis material. The basis material must first be alkaline cleaned, thoroughly rinsed, and forced-air dried prior to conversion coating. The conversion coating solution is applied with a roll mechanism used in roll coating paint. Once the solution is roll coated onto the basis material, the coil is forced-air dried at approximately 66°C. The no-rinse solutions are formulated in such a way that once a film is formed and dried, there are no residual or detrimental products left on the coating that could interfere with normal coil coating paint formulations.

Although no-rinse conversion coatings currently represent a small proportion of the conversion coating techniques that are used, they offer several advantages, including fewer process steps in a physically smaller process line, higher line speeds, application of a very uniform thickness by roll coating rather than spray or dip coating, and reduction of waste treatment requirements because of the reduced use of chromium compounds. Disadvantages include roll coating mechanism wear possibly reducing quality, the closer coordination of the entire line that is needed, difficulty in adaptation, and the hazardous organic acids content of the no-rinse conversion coating chemicals.

7.4 PAINTING OPERATION OF COIL COATING

Roll coating of paint is the final process in a coil coating line. Roll coating is an economical method to paint large areas of metal with a variety of finishes and to produce a uniform and high-quality coating. The reverse roll procedure for coils is used by the coil coating industry, and allows both sides of the coil to be painted simultaneously.

The paint formulations used in the coil coating industry have high pigmentation levels (providing hiding power), adhesion, and flexibility. Most coatings of this type are thermosetting and are based on vinyl, acrylic, and epoxy functional aromatic polyethers, and some reactive monomer or other resin with reactive functions, such as melamine formaldehyde resins. Also, a variety of copolymers of butadiene with styrene or maleic anhydride are used in coating formulations. These coatings are cured by oxidation mechanisms during baking, similar to those that harden drying oils.

After paint application, all coils are cured in an oven. Curing temperatures depend upon basis material, conversion coating, paint formulation, and line speed. Typical temperatures range from ~93°C to a maximum of ~454°C. Upon leaving the oven, the coils are quenched with water to induce rapid cooling prior to rewinding.

The quench is necessary for all basis materials, conversion coatings, and paint formulations. A coil that is rewound when too warm will develop internal and external stresses, causing a possible degradation of the appearance of the paint film and of the forming properties of the coil. The volume of water used in the quench often has the largest flow rate of all of the coil-coating processes. However, the water is often circulated to a cooling tower for heat dissipation and reuse.

The finished coils are used in a variety of industries. The building products industry utilizes prefinished coils to fabricate exterior siding, window and door frames, storm windows, storm gutters, and various other trim and accessory building products. The food and beverage industries utilize various types of coils and finishes to safely and economically package and ship a wide variety of food and beverage products. Until recently, the automotive and appliance industries have made limited use of prefinished coils. These industries have relied on postassembly finishing of their products. Recently, the automotive industry has begun using a cold rolled steel coil coated on one side with a finish called Zincrometal. This coating is applied to the under surfaces of exterior automobile sheet metal to protect them from corrosion. The appliance industry uses prefinished coils in constructing certain models of refrigerator exteriors to provide a finished product that minimizes the costly and labor-intensive painting operation after forming.

Coil coating operations are located throughout the country, usually in well established industrial centers. Compared to some other industries, coil coating operations are not physically large. Coil coating operations use large quantities of water and are often a significant contributor to municipal waste treatment systems or surface waters. In addition, the curing ovens from coil coating operations are a source of air pollution in the form of reactive hydrocarbons.

7.5 SUBCATEGORIES OF THE COIL COATING INDUSTRY 7.5.1 General Description of Subcategorization

The primary purpose of subcategorization is to establish groupings within the coil coating industry such that each group has a uniform set of effluent limitations. Although subcategorization is based on wastewater characteristics, a review of the other subcategorization factors reveals that the basis material used and the processes performed on these basis materials are the principal factors affecting the wastewater characteristics of plants in the coil coating industry. The coil coating industry is therefore divided into the following three subcategories:

1. Coil coating on steel

2. Coil coating on zinc-coated steel (galvanized)

3. Coil coating on aluminum or aluminized steel

Of all coil coating plants in the U.S., about 36% of the plants pretreat their industrial effluents and directly discharge their pretreated effluents to the receiving waters, and the remaining 54% of the plants pretreat and discharge their effluents to the municipal wastewater treatment plants for further treatment. The following subsections describe the above subcategories.1-3

7.5.2 Coil Coating on Steel Subcategory

In the U.S., 59 facilities in the coil coating industry were surveyed for process type and pollutant levels. Of these, 38 plants are in the coil coating on steel subcategory. Ten facilities coat steel alone and the remaining 28 coat a combination of steel coils and coils from the other subcategories. The production rate is approximately 85,000 m2/h. Operations used at these facilities include acid cleaning, strong alkaline cleaning, phosphating, no-rinse conversion coating, roll coating, and Zincrometal coating. Water usage rates for the general operations at steel coating facilities are listed in Table 7.1.

7.5.3 Coil Coating on Zinc Coated Steel (Galvanized Steel) Subcategory

Within the 59 plants surveyed, 17 coil coat on galvanized steel with a production of ~60 x 103 m2/h. Only two facilities produce coated galvanized steel alone. Operations used at the galvanized coating facilities include mild alkaline cleaning, phosphating, chromating, complex oxide treatment, no-rinse conversion coating, roll coating, and Zincrometal coating. Table 7.1 also presents water usage data for the general operations at galvanized coating facilities.1,2

TABLE 7.1

Summary of Water Usage Rates for the Coil Coating Industry by Subcategory

Number of Plants

TABLE 7.1

Summary of Water Usage Rates for the Coil Coating Industry by Subcategory

Number of Plants

Operation

Sampled

Range

Mean

Steel

Cleaning

11

0.04-7.3

1.9

Conversion coating

8

0.04-0.76

0.43

Quenching

4

2.0-5.7

4.0

All operations

13

0.37-13

4.5

Galvanized

Cleaning

10

0.17-8.8

1.9

Conversion coating

10

0.03-0.98

0.49

Quenching

5

0.44-5.1

2.7

All operations

12

0.65-8.4

3.6

Aluminum

Cleaning

12

0.21-2.0

0.97

Conversion coating

12

0.18-1.8

0.56

Quenching

9

1.2-3.5

2.3

All operations

15

0.26-5.8

2.5

Source: U.S. EPA, Development Document for Effluent Limitations Guidelines and Standards for the Coil Coating Point Source Category (Canmaking Subcategory), Final report 440/1-83/071, Washington, DC, November 1983; U.S. EPA, Coil Coating Forming Point Source Category, available at http://www.access.gpo.gov/nara/cfr/waisidx_03/40cfr467_03.html, 2008.

Source: U.S. EPA, Development Document for Effluent Limitations Guidelines and Standards for the Coil Coating Point Source Category (Canmaking Subcategory), Final report 440/1-83/071, Washington, DC, November 1983; U.S. EPA, Coil Coating Forming Point Source Category, available at http://www.access.gpo.gov/nara/cfr/waisidx_03/40cfr467_03.html, 2008.

7.5.4 Coil Coating on Aluminum Subcategory

Thirty-nine of the facilities in the U.S. coil coat on aluminum with a production rate of 90 x 103 m2/h. Nineteen facilities coat only aluminum coils. The aluminum coating facilities use mild alkaline cleaning, phosphating, chromating, complex oxide treatment, no-rinse conversion coating, and roll coating. Water usage rates for the general processes in this subcategory are listed in Table 7.1.

Water is used in virtually all coil coating operations. It provides the mechanism for removing undesirable compounds from the basis material, is the medium for the chemical reactions that occur on the basis material, and cools the basis material following baking. Water is the medium that permits the high degree of automation associated with coil coating and the high quality of the finished product. The nature of coil coating operations, the large amount of basis material processed, and the quantity and type of chemicals used produces a large volume of wastewater that requires treatment before discharge.

Wastewater generation occurs for each basis material (steel, galvanized and aluminum) and for each functional operation (cleaning, conversion coating, and painting). The wastewater generated by the three functional operations may be handled in one of the following ways:

1. It may flow directly to a municipal wastewater treatment system or surface water.

2. It may flow directly to an onsite waste treatment system and then to a municipal wastewater treatment system or surface water.

3. It may be reused directly or following intermediate treatment.

4. It may undergo a combination of the above processes.

Coil coating operations that produce wastewater are characterized by the pollutant constituents associated with respective basis materials. The constituents in the raw wastewaters include ions of the basis material, oil and grease found on the basis material, components of the cleaning and conversion coating solutions, and the paints and solvents used in roll coating the basis materials. The following tables present wastewater characterization data for each subcategory. The data presented are the results of verification analysis of the industry. Prior to verification sampling, a screening program was conducted to identify the presence or absence of the 129 priority pollutants. Those pollutants detected in screening at a concentration greater than 10 ^g/L were further studied in the verification analysis. The minimum detection limit in the verification analysis for pesticides was 5 |ag/L and for all other toxic pollutants, 10 ^g/L. Any value below its detection limit is presented in the following tables as below detection limit (BDL).

Tables 7.2 through 7.5 present raw wastewater characterization data for each general process in each subcategory and for the wastewater in each subcategory when combined into a single representative stream as a whole. Table 7.6 presents raw wastewater flow data for each subcategory.

7.6 WASTEWATER CHARACTERIZATION OF THE COIL COATING INDUSTRY

7.6.1 Effluent Characteristics of Coil Coating on Steel Operation

Wastewaters from the coil coating on steel subcategory generally have higher levels of phosphorus than that from the other subcategories because of the use of concentrated phosphate alkaline cleaners. Oil and grease in this subcategory are also found in larger concentrations than the other basis materials' wastewater because of the increased raw material protection needed to inhibit rust. This can often cause an increase in the number of hydrocarbons found in the wastewater. Suspended solids may be at higher levels because of the adhering dirt in the oil.1-3

7.6.2 Effluent Characteristics of Coil Coating on Zinc Coated Steel (Galvanized Steel) Operation

Coil coating on galvanized steel generally produces significant suspended solids concentrations in wastewater. Another pollutant problem is the high concentration of dissolved zinc and iron in the

Ki Oi 05

TABLE 7.2

Toxic and Classical Pollutants in Raw Wastewater of the Steel Subcategory, Verification Data

TABLE 7.2

Number of

Number of

Range of

Mean" of

Number of

Number of

Range of

Mean" of

Pollutant

Samples

Detections

Samples

Samples

Samples

Detections

Samples

Samples

ncininc Onpntinir:

—,

—■

rnnvpfiinn Onpntinni

V^ICdl 1 II lU Kyuci (11IUI 13

*

- 1VCI 3IUI I Kyuci dllUI 13 -

Toxic Organic Pollutants (yg/L)

1,1 -Trichloroethane

6

5

ND-BDL

BDL

8

3

ND-40

BDL

1,1 -Dichloroethane

5

0

7

1

ND-77

11

1,1 -Dichloroethylene

2

0

2

0

1,2-trans-Dichloroethylene

2

0

2

0

2,4-Dimethylphenol

3

0

3

0

Fluoranthene

9

1

ND-68

BDL

7

1

ND-BDL

BDL

Isophorone

9

1

ND-18

BDL

7

0

Naphthalene

9

2

ND-20

BDL

7

4

ND-BDL

BDL

Phenol

3

0

3

0

Bis(2-ethylhexyl)phthalate

9

7

ND-150

34

7

5

ND-110

20

Butyl benzyl phthalate

9

1

ND-360

40

7

0

Di-n-butyl phthalate

9

5

ND-30

BDL

7

3

ND-14

BDL

Di-n-octyl phthalate

9

3

ND-BDL

BDL

7

1

ND-760

110

Diethyl phthalate

9

6

ND-210

46

7

6

ND-180

100

Dimethyl phthalate

9

0

7

0

1,2-B enzanthracene

9

2

ND-30

BDL

7

0

Benzo(a)pyrene

9

0

7

0

3,4-Benzo fluoranthene

9

0

7

0

Benzo(k)fluoranthene

9

0

7

0

Chrysene

9

2

ND-30

BDL

7

0

Acenaphthylene

9

1

ND-BDL

BDL

7

1

ND-BDL

BDL

Anthracene

9

7

ND-280

51

7

3

ND-BDL

BDL

1,1,2-Benzoperylene

9

0

7

0

Fluorene 9

Phenanthrene 9

1,2,5,6-Dibenzanthracene 9

Ideno(l,2,3-cd)pyrene 9

Pyrene 9

Toluene 3

Trichloroethylene 6

Toxic Metals and Inorganics (yg/L)

Cadmium 9

Chromium, total 9

Chromium, hexavalent 9

Copper 9

Cyanide, total 8

Cyanide, amn. to chlorine 8

Lead 9

Nickel 9

Zinc 9

Classical Pollutants (mg/L)

Aluminum 9

Fluorides 9

Iron 9

Manganese 9

Oil and grease 9

Phenols, total 9

Phosphorus 7

TDS 4

TSS 9

ND-BDL ND-280

ND 51

ND-22

ND-BDL ND-620

21-180

ND-120

ND-99

ND-1100

ND-210

220-42,000

ND-0.85

0.93-80

9.8-1600

ND-0.27

11-78

1100-17,000 52-440

BDL 210

70 28 17 240 38 10,000

0.35

0.18

9300 220

ND-BDL ND-BDL

BDL BDL

ND-89

ND-73

280-920,000

ND-410,000

ND-160

ND-92

ND-12

ND-3600

ND-19,000

530-140,000

ND-11

ND-18

ND-0.23

3300-3500

27-250

13 10

320,000 110,000 41 12

BDL 530 4,000 54,000

3400 130

Source: U.S. EPA, Development Document for Effluent Limitations Guidelines and Standards for the Coil Coating Point Source Category (Canmaking Subcategory), Final report 440/1-83/071,

Washington, DC, November 1983; U.S. EPA, Coil Coating Forming Point Source Category, available at http://www.access.gpo.gov/nara/cfr/waisidx_03/40cfr467_03.html, 2008. BDL, below detection limit; ND, not detected. a BDL was calculated in the mean concentration as equal to zero.

Ki O

TABLE 7.3

Toxic and Classical Pollutants in Raw Wastewater of the Galvanized Subcategory, Verification Data

TABLE 7.3

Number of

Number of

Range of

Mean" of

Number of

Number of

Range of

Mean1

Pollutant

Samples

Detections

Samples

Samples

Samples

Detections

Samples

Samp

n___^________

________

^________

Cleaning operations

conversion

operations

Toxic Organic Pollutants (yg/L)

1,1,1 -Trichloroethane

10

4

ND-BDL

BDL

10

4

ND-140

21

1,1 -Dichloroethane

1

0

1

0

1,1 -Dichloroethylene

10

0

10

1

ND-BDL

BDL

1,2-iraras-dichloroethylene

10

0

10

2

ND-15

BDL

2,4-Dimethyl phenol

2

0

2

0

Fluoranthene

10

3

ND-BDL

BDL

10

1

ND-23

BDL

Isophorone

10

1

ND-47

BDL

10

1

ND-520

52

Naphthalene

10

2

ND-38

BDL

10

5

ND-15

BDL

Phenol

4

0

4

0

Bis(2-ethylhexyl) phthalate

10

9

ND-340

110

10

9

ND-1200

220

Butyl benzyl phthalate

10

1

ND-130

13

10

3

ND-BDL

BDL

Di-n-butyl phthalate

10

7

ND-170

30

10

3

ND-20

BDL

Di-n-octyl phthalate

10

1

ND-BDL

BDL

10

0

Diethyl phthalate

10

8

ND-420

110

10

9

ND-300

77

Dimethyl phthalate

10

0

10

0

1,2-Benzanthracene

10

4

ND-27

13

10

1

ND-BDL

BDL

Benzo(a)pyrene

10

0

10

0

3,4-Benzo fluoranthene

10

0

10

0

Benzo(k)fluoranthene

10

0

10

0

Chrysene

10

4

ND-27

BDL

10

1

ND-BDL

BDL

Acenaphthylene

10

0

10

1

ND-BDL

BDL

Anthracene

10

3

ND-250

27

10

3

ND-290

29

1,1,2-Benzoperylene

10

0

10

0

Fluorene

10

4

ND-85

13

10

1

ND-BDL

BDL

Phenanthrene

10

3

ND^17

BDL

10

3

ND-290

29

1,2,5,6-Dibenzanthracene

10

0

10

0

Ideno(l ,2,3-cd)pyrene

10

0

10

0

Pyrene

10

3

ND-BDL

BDL

10

1

ND-11

BDL

Toluene

4

0

4

0

Trichloroethylene

10

2

ND-BDL

BDL

10

2

ND-110

14

Toxic Metals and Inorganics (yg/L)

Cadmium

10

8

ND-120

36

10

5

ND-110

21

Chromium, total

10

9

ND-610

280

10

10

3400-780,000

290,000

Chromium, hexavalent

9

1

ND-260

29

10

10

50-310,000

140,000

Copper

10

9

ND-57

27

10

8

ND-140

25

Cyanide, total

10

4

ND^13

BDL

10

5

ND-470

150

Cyanide, amn. to chlorine

10

3

ND-21

BDL

10

4

ND-330

48

Lead

10

9

ND-2600

1,400

10

10

BDL-1300

560

Nickel

10

1

ND-150

15

10

6

ND-31,000

4600

Zinc

10

10

690-120,000

63,000

10

10

33,000-710,000

220,000

Classical Pollutants (mg/L)

Aluminum

10

9

ND^l.9

2.2

10

9

ND-11

3.2

Fluorides

10

10

0.16-16

2.5

10

10

1.5-71

16

Iron

10

10

0.19-17

4.8

10

10

0.84-21

6.6

Manganese

10

9

ND-0.73

0.17

10

10

0.035-1.3

0.25

Oil and grease

10

10

10-970

270

10

10

1.3-110

19

Phenols, total

9

7

ND-0.079

0.029

10

7

ND-0.067

0.015

Phosphorus

9

9

9.4-56

33

7

7

3.8-66

33

TDS

1

1

2001

1

1

2,500

TSS

10

10

19-630

250

10

10

68-450

250

Source: U.S. EPA, Development Document for Effluent Limitations Guidelines and Standards for the Coil Coating Point Source Category (Canmaking Subcategory), Final report 440/1-83/071,

Washington, DC, November 1983; U.S. EPA, Coil Coating Forming Point Source Category, available at http://www.access.gpo.gov/nara/cfr/waisidx_03/40cfr467_03.html, 2008. BDL, below detection limit; ND, not detected. a BDL was calculated in the mean concentration as equal to zero.

Ki Ki

TABLE 7.4

Toxic and Classical Pollutants in Raw Wastewater of the Aluminum Subcategory, Verification Data

TABLE 7.4

Number of

Number of

Range of

Mean" of

Number of

Number of

Range of

Mean" of

Pollutant

Samples

Detections

Smaples

Samples

Samples

Detections

Samples

Samples

,—

__

,—

__

Cleaning Opeialions

Conversion Opeialions

Toxic Organics (yg/L)

Fluoranthene

12

0

12

0

Isophorone

12

0

12

0

Naphthalene

9

3

ND-BDL

BDL

12

3

ND-BDL

BDL

Phenol

2

0

2

0

Bis(2-ethylhexyl)phthalate

12

10

ND-450

no

12

9

ND-300

37

Butyl benzyl phthalate

12

0

12

Di-n-butyl phthalate

12

2

ND-12

BDL

12

2

ND-BDL

BDL

Di-n-octyl phthalate

12

0

12

1

ND-BDL

BDL

Diethyl phthalate

12

7

ND-450

99

12

9

ND-200

57

Dimethyl phthalate

12

2

ND-BDL

BDL

12

I

ND-110

BDL

1,2-Benzanthracene

12

0

12

0

Benzo(a)pyrene

12

3

ND-BDL

BDL

12

2

ND-BDL

BDL

3,4-Benzo fluoranthene

12

0

12

0

Benzo(k)fluoranthene

12

0

12

0

Chrysene

12

0

12

0

Acenaphthylene

12

0

12

0

Anthracene

12

2

ND-BDL

BDL

12

4

ND-BDL

BDL

1,1,2-Benzoperylene

12

0

12

0

Fluorene

12

1

ND-BDL

BDL

12

0

Phenanthrene

12

2

ND-BDL

BDL

12

4

ND-BDL

1,2,5,6-Dibenz anthracene 12

Ideno(l,2,3-cd)pyrene 12

Pyrene 12

Toluene 2

Toxic Metals and Inorganics (yg/L)

Cadmium 12

Chromium, total 12

Chromium, hexavalent 11

Copper 12

Cyanide, total 12

Cyanide, amn. to chlorine 12

Lead 12

Nickel 12

Zinc 12

Classical pollutants, (mg/L)

Aluminum 12

Fluorides 12

Iron 12

Manganese 12

Oil and grease 12

Phenols, total 12

phosphorus 9

TSS 12

6 12

ND-21

ND-6000

ND-6600

ND-210

ND-260

ND-240

ND-220

ND-14,000

8.6-940

0.077-0.69

ND-15

ND-2800

ND-0.16

ND-100

6.0-970

1300

12 12 12 2

3 12 12 10

4 12

ND-19

15,000-960,000

11,000-330,000

ND-980

ND-7500

ND-7000

ND-400

ND-260

16^13,000

11^10

17-510

0.049-12

ND-60

ND-0.14

13-16

4.2-1200

BDL 270,000 120,000 160 2400 1400 48 40 8800

era CD

Source: U.S. EPA, Development Document for Effluent limitations Guidelines and Standards for the Coil Coating Point Source Category (Canmaking Subcategory), Final report 440/1-83/071,

Washington, DC, November 1983; U.S. EPA, Coil Coating Forming Point Source Category, available at http://www.access.gpo.gov/nara/cfr/waisidx_03/40cfr467_03.html, 2008. BDL, below detection limit; ND, not detected. a BDL was calculated as equal to zero in the mean concentration.

Ki W

TABLE 7.5

Toxic and Classical Pollutants in Quenching Raw Wastewater of All Subcategories, Verification Data

Number of Pollutant Samples

Toxic Organic Pollutants (yg/L) 1, 1, 1-Trichloroethane 9

1, 1-Dichloroethane 3

1, 1-Dichloroethylene 6

1, 2-trans-Dichloroethylene 6

2, 4-Dimethylphenol 3 Fluoranthene 18 Isophorone 18 Naphthalene 18 Phenol 7 Bis(2-ethylhexyl)phthalate 18 Butyl benzyl phthalate 18 Di-n-butyl phthalate 18 Di-n-octyl phthalate 18 Diethyl phthalate 18 Dimethyl phthalate 18 1,2-Benzanthracene 18 Benzo(a)pyrene 18 3,4-Benzo fluoranthene 18 Benzo(k)fluoranthene

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