# Effluent Limitations Guidelines, Pretreatment Standards, and New Source Performance Standards for the Metal Products and Machinery Point Source Category; Notice of Data Availability

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URL: https://www.frixlaw.com/law-library/documents/fr%3A02-13808

## Record

- **Collection:** Federal Register
- **Document type:** Proposed Rule
- **Published:** June 5, 2002
- **Citation:** 67 FR 38752

## Text

ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 413, 433, 438, 463, 464, 467, and 471
[FRL-7221-4]
RIN 2040-AB79
Effluent Limitations Guidelines, Pretreatment Standards, and New Source Performance Standards for the Metal Products and Machinery Point Source Category; Notice of Data Availability

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Notice of data availability.

SUMMARY:

On January 3, 2001 (66 FR 424), EPA published a proposal to establish technology-based effluent limitations guidelines and pretreatment standards for the metal products and machinery (MP&M) point source category. The proposal would apply to approximately 10,000 facilities that manufacture, rebuild, or maintain metal products, parts, or machines in eight regulatory subcategories. EPA developed the proposal to address changes in the metal finishing and electroplating sectors over the last 20 years, including measures that reduce pollution. The proposal would establish national regulations for some industry sectors for the first time as well as increasing the degree of environmental protection from that achieved under the previous rules.

In the proposal, EPA specifically solicited comment on 43 issues in addition to the general comment solicitation. EPA received comments from various stakeholders, including State and local regulatory authorities, environmental groups, individual industrial facilities and industry groups, and private citizens.

This document presents a summary of data received in comments since the proposal and additional data collected by EPA and describes how these data may be used by EPA in developing final MP&M regulations.

EPA is evaluating how the comments and new data may change certain aspects of the proposal and how this information might affect the regulatory options considered for the proposal. EPA is also evaluating the underlying data and methodology that EPA uses to estimate the costs, pollutant load reductions, and financial impacts associated with the regulation in light of the comments and new information. The document describes EPA's current thinking on these subjects and presents information on how the new data and information received since proposal would affect the proposed limitations and standards. Today, EPA is making these data and new information available for public review and comment. EPA solicits public comment on the issues and information presented in this notice of data availability and in the administrative record supporting this document.

DATES:

You must submit comments by July 22, 2002.

ADDRESSES:

Public comments regarding this document should be submitted electronically to
mpm.comments@epa.gov.
You also may submit comments by mail to: Metal Products & Machinery Rule, Office of Water, Engineering and Analysis Division (4303T), USEPA, 1200 Pennsylvania Avenue, NW, Washington, DC 20460. You should submit hand-deliveries (including overnight mail) to the Metal Products & Machinery Rule, USEPA, 1201 Constitution Ave, NW, Room 6231G EPA WEST, Washington, DC 20004. Please submit an original and three copies of your written comments and enclosures as well as any references cited in your comments. Commenters who want EPA to acknowledge receipt of their comments should enclose a self-addressed, stamped envelope. EPA will not accept facsimiles (faxes). For additional information on how to submit electronic comments see
SUPPLEMENTARY INFORMATION,
How to Submit Comments.

The public record for this action and the proposed rulemaking has been established under docket number W-99-23 and is located in the Water Docket East Tower Basement, Room EB57, 401 M Street SW, Washington, DC 20460. The record is available for inspection from 9:00 a.m. to 4:00 p.m., Monday through Friday, excluding legal holidays. For access to the docket materials, call (202) 260-3027 to schedule an appointment. A reasonable fee may be charged for copying.

FOR FURTHER INFORMATION CONTACT:

For additional information, contact Mr. Carey A. Johnston at (202) 566-1014 or at the following e-mail address:
johnston.carey@epa.gov.

SUPPLEMENTARY INFORMATION:

How To Submit Comments

Electronic comments must specify docket number W-99-23 and must be submitted as an ASCII, Microsoft Word 97 file, or Word Perfect 5/6/7/8/9 file avoiding the use of special characters and any form of encryption. EPA will also accept comments and data on disks in any of the above listed file format. You may file electronic comments on this action at many Federal Depository Libraries. No confidential business information (CBI) should be sent via e-mail.

Contents of This Document

I. Purpose of this Document

II. New Analytical Data and Information

A. EPA Site Visits & Sampling Episodes

B. Industry Submitted Data

C. Analytical Method Validation Study and the Total Organics Parameter

III. Revisions & Corrections to the Cost & Loadings Model

A. Subcategorization of Facilities and Unit Operations Data

B. Pollutant Specific Revisions to Loadings and Removals

C. Stream Code Corrections

D. Change in Imputed Flows

E. Changes Considered for Methodology for Treatment-In-Place Credits

F. Revisions to the Cost Modules

G. New Survey Weights

IV. Changes Considered to Applicability, Definitions, and Regulated Pollutants

A. Changes Considered to Applicability and Definitions

B. Changes Considered to the Pollutants Selected for Regulation

V. New Information and Consideration of Revision to Economic & Benefit Methodologies

A. Revised Cost Pass-Through and Market Structure Analysis

B. Consideration of Changes to Closure and Financial Stress Test Methodologies

C. Consideration of Changes to Cash Flow Calculations

D. Updating Survey Data to Current Dollars

E. Adjusting Abnormally High Labor Cost Estimates

F. New Information on POTW Administrative Costs

G. Human Health Benefits from Reduced Exposure to Lead

H. Ohio Case Study

I. Recreational Benefits

J. POTW Characteristics

K. Drinking Water Intakes

L. Extrapolation of Sample-Based Results to the National Level

VI. Consideration of Preliminary Revised Limitations and Standards

A. Preliminary Revised Limitations and Standards

B. Alternative Approaches Considered to TOP Limitations and Standards

C. Consistency of Statistical Methodology With Other Recent Effluent Guidelines

VII. Revised Estimates of Costs, Loadings, Economic Impacts, and Cost-Effectiveness

A. Revised National Estimates of Economic Impacts

B. Revised National Estimates of Cost-Effectiveness

C. Results for the Sand Filter Option

D. Revised National Estimates of Monetized Benefits

VIII. Preliminary Revised Limitations and Standards

A. Technology Option 2

B. Technology Option 4

C. Technology Option 6

D. Technology Option 10

IX. Consideration of Alternative Options

A. Consideration of Change in New Source Technology Option for Metal-Bearing Subcategories

B. General Metals Subcategory

C. Metal Finishing Job Shops Subcategory

D. Printed Wiring Board Subcategory

E. Oily Wastes Subcategory

F. Railroad Line Maintenance Subcategory

G. Steel Forming & Finishing Subcategory

X. Solicitation of Comment

I. Purpose of This Document

Today's document has several purposes. First, EPA is presenting a summary of new data and information submitted during the public comment period on the proposed MP&M regulations as well as data collected by EPA since proposal. Second, EPA discusses major issues raised in comments on the proposal and revisions in the data analyses resulting from these comments and the additional data. Third, the document summarizes EPA's current thinking on how this new information and suggestions made by commenters affect the analyses of the proposed rule. The document also summarizes the changes EPA is considering for the final rule in light of the new material. Finally, the document includes modified potential effluent limitations and pretreatment standards as revised to take account of the new data as well as revised information on the cost and removals associated with various treatment options.

EPA has incorporated into the data base used for developing the proposed MP&M effluent limitations and pretreatment standards a significant amount of new data and corrections to the proposal data. For a number of the subcategories proposed for regulation, these modifications have resulted in substantial changes in the estimated cost and pollutant removals associated with the treatment options considered at proposal. As a consequence, in several instances, the economic impact and cost effectiveness of the treatment options are now much higher than projected at proposal (Note that a “high” cost-effectiveness figure means an option is not very cost effective). In some cases, the proposed effluent limitations and pretreatment standards would have impacts greater than EPA has traditionally determined to be economically achievable. Furthermore, limiting the effluent limitations and standards to facilities with higher treatment flows—so-called flow cutoffs—would not appear to mitigate economic effects in any meaningful way for certain subcategories proposed for regulation. In light of these new results, EPA is seeking further comment on the regulatory options considered for the proposal as well as several other options for reducing the economic impact of the final rule.

The document includes seven main components:

(1) Discussion of new analytical data and information;

(2) Revisions to EPA's costs and pollutant loading model and methodologies that incorporate new data;

(3) Possible changes to the applicability of the rule, definitions, and selection of regulated pollutants for the final rule as a result of the new information;

(4) New information and revisions that EPA may use for its economic and benefit methodologies;

(5) New information and revisions that EPA may use for its statistical methodologies;

(6) Revised estimates of costs, loadings, economic impacts, benefits, and numerical limitations and standards; and

(7) Discussion of possible alternative options based on new data and information.

This document addresses these issues related to the proposed MP&M regulation. To the extent possible, today's document describes new analyses that may be performed by EPA and describes revisions EPA is considering to EPA's financial and engineering models, as well as possible new data or methodologies. By providing this information, it is EPA's intention to present the clearest picture of its current thinking about how the proposal may change as a result of the additional information it has obtained. It is EPA's hope that this information will encourage effective comment.

This document also contains a discussion of ways that EPA may reduce impacts and/or enhance flexibility of the regulation, including options to encourage implementation of environmental management systems (EMS) or “no further regulation” options for certain subcategories. EPA received comments concerning these matters and in this document requests further information. The document also outlines potential changes to the regulatory thresholds (e.g., “low wastewater flow cutoff”) that were proposed to reduce impacts.

New data that EPA may use in its cost and economic models include estimates from EPA and industry wastewater sampling of MP&M unit operations of pollutant loading in raw wastewater and new information related to various EPA modeling assumptions. EPA also received more than 136 new data sets with proposal comments. EPA used 75 of these new data sets for developing numerical limitations.

Through this notice of data availability, EPA seeks further public comment on any and all aspects of the specific data and issues it has identified here. However, EPA is seeking public comment
only
on these specific data and issues. Nothing in today's document is intended to invite further discussion of other issues discussed in the MP&M proposal or to reopen the proposal in general for additional public comments. EPA continues to review the comments already submitted on the proposed rule and will address those comments, along with comments submitted on the data and issues identified in today's document, in the final rulemaking.

II. New Analytical Data and Information

There are three general areas of new analytical data: (1) EPA post-proposal sampling, (2) industry self-sampling, and (3) EPA's analytical method validation study. First, in response to public comments, EPA has performed a number of analytical wastewater sampling episodes since the publication of the proposed rule to collect additional data on raw wastewater loadings, treatment efficiencies, and treatment variability. In addition, facilities and industry trade associations submitted a large quantity of analytical water sampling data (“self-monitoring data”) along with their written comments on the MP&M proposal to EPA. Finally, as discussed in the proposed rule (66 FR 529), EPA has performed a study to validate EPA Analytical Methods 1624B/624 and 1625/625 for several organic pollutants that are part of the proposed “Total Organics Parameter” (TOP).

A. EPA Site Visits & Sampling Episodes

During the comment period and at the public meetings on the proposal, commenters raised concerns over the representativeness of EPA's database concerning metal finishing “zinc” platers, printed wiring board facilities, and the steel forming and finishing facilities. Based on these concerns EPA worked with industry trade associations to identify facilities in these groups that would be good candidates for EPA's post-proposal wastewater sampling program. EPA visited 6 metal finishing zinc platers (4 job shops, 2 captive), 8 printed wiring board facilities, 4 steel forming and finishing facilities, and 2 other MP&M facilities (i.e., metal finishing job shops that do not specialize in zinc plating). Based on the

information collected during the site visits, which included information on a variety of MP&M unit operations being performed, whether the site was employing technology considered to be “Best Available Technology,” sampling logistics, and production schedule, EPA selected facilities for analytical wastewater sampling. EPA performed wastewater sampling at 2 metal finishing zinc platers that operate as job shops, 3 printed wiring board facilities, and 2 steel forming and finishing facilities. EPA collected characterization samples of wastewater from typical MP&M operations and paired influent and effluent samples from each of these facilities' treatment systems. In addition, EPA obtained long-term monitoring data from all sampled sites for use in calculating new variability factors and long-term averages for revising numerical limits. EPA also obtained long-term monitoring data from several facilities that EPA visited but did not sample: two zinc platers that operate as captive facilities, one printed wiring board facility, and one steel forming and finishing facility. EPA is using these additional data sets and data used at proposal for revising numerical limits. Non-confidential versions of these Site Visit Reports (SVRs) and Sampling Episode Reports (SERs) can be found in sections 15.2 and 15.3 of the public record for this document (Docket Number W-99-23).

Although EPA does have survey questionnaires for the facilities in the Steel Forming & Finishing (SFF) Subcategory, EPA did not sample any SFF facilities prior to proposal. EPA did solicit data from such facilities. As explained in the proposal (66 FR 530), EPA is planning to revise the list of regulated pollutants and the numerical limitations for the SFF Subcategory based on post-proposal sampling data. For proposal, EPA based the selection of regulated pollutants and numerical limits on data from the General Metals subcategory. See section IV of today's document for a list of pollutants currently under consideration for regulation (
see
a memorandum entitled, “Selection of Regulated Pollutants for the Steel Forming & Finishing Subcategory,” section 16.2 of the public record, DCN 16876 for a discussion of the selection of regulated pollutants.)

As described in the proposed rule (66 FR 534), EPA solicited comment on the appropriate analytical method for analyzing total sulfide in wastewater from MP&M facilities. When EPA performed analytical testing on the wastewater samples collected post-proposal, EPA used three different analytical methods to detect total sulfide:

• Method 376.1, a titrimetric method that was used by EPA for the majority of its sulfide analyses for proposal;

• Method 376.2, a colorimetric method suggested by industry as an alternate choice and used by EPA for one sampling episode for proposal; and

• Method 4500-S
−2
(E) from the 18th edition of Standard Methods for the Examination of Water and Wastewater, a titrimetric method similar to Method 376.1. Method 4500-S
−2
(C), a pretreatment procedure, is recommended for reducing interferences (e.g., thiosulfate, sulfite, and various organic compounds) and/or concentrating the sample to achieve greater sensitivity. Method 4500-S
−2
(E) was run using this pretreatment procedure in the post-proposal sampling program.

All three of these methods are currently approved at 40 CFR part 136 for compliance monitoring.

EPA collected sulfide data for 236 samples in seven post-proposal sampling episodes using all three of these sulfide methods (EPA Episode numbers 6455, 6456, 6457, 6458, 6461, 6462, and 6463). These samples were collected from both process wastewaters prior to treatment and effluent wastewater after treatment. Of those 236 samples, 156 samples (66%) had no sulfide detected by any of the three methods. The reported detection limits for the three methods differ as a function of the analytical techniques, and thus, EPA does not intend to investigate these results further.

One of the 236 samples had results for all three methods that were invalidated during the data review process because of extreme difficulties during the analysis. An additional 79 samples (33%) had sulfide detected by one or more of the three methods. These 79 samples will tell us the most about the performance of the methods in the MP&M wastewaters. Of those, only 12 samples had sulfide detected by all three methods, while the remaining 67 samples were a mixture of detected sulfide and non-detect results.

EPA provides a detailed review of these 67 samples with “mixed results” and the 12 samples with detects by all three methods in a document titled, “Evaluation of Sulfide Results for Metal Products and Machinery Samples Analyzed by MCAWW Method 376.1, MCAWW Method 376.2, and Standard Method 4500-S
−2
(E)” (
see
section 16.2, DCN 16941).

Because the true concentrations of sulfide in these 236 samples are not known, it is not possible to state with certainty which of the three methods used in this study (DCN 16941) performs best overall. The results for the 236 samples in this study suggest that there are potential interferences with Method 376.1 that may be better addressed by either Method 376.2 or SM 4500-S
−2
(E) and its associated sample pretreatment step. The fact that sulfide was not detected by any of the methods in approximately 66% of all the samples, suggests that the differences between the methods need to be viewed in the context of specific samples and sample types.

Of the 26 effluent samples where EPA detected sulfide by one or more of the three methods, eight samples were detected by all three methods. These results indicate that the performance of the three methods can be comparable in the sample type to which these methods are most often applied (
i.e.,
treated effluents), and in samples whose sulfide concentrations fall within the range of all three methods. The data from the other effluent samples and from the influents and unit process samples suggest that: (1) Method 376.2 may perform better than SM 4500-S
−2
(E); and (2) when the sample pretreatment procedure in SM 4500-S
−2
[C] is employed, SM 4500-S
−2
(E), in turn, may perform better than Method 376.1.

B. Industry Submitted Data

In addition to their written comments, many MP&M facilities and a few POTWs submitted data to be used in developing the numerical limits for the final rule. EPA is using over 46 data sets of long-term self-monitoring compliance data from “BAT” facilities that met our criteria. In addition, EPA is using paired influent/effluent data received from an additional 37 “BAT” facilities and characterization data for MP&M unit operations (
i.e.,
in-plant raw wastewater) from three facilities.

EPA extensively reviewed the data submitted as comment to the proposed rule. EPA reviewed the data for completeness when compared to the “Guidelines for Submission of Analytical Data” in the proposed rule (66 FR 537). EPA contacted facilities to follow up on missing information when only a few items were not included (
e.g.,
a treatment flow diagram or identification of sampling points). For the 75 data sets of the 136 submitted with proposal comments, EPA has been able to include the data and use them for calculating the revised limits presented in today's document. Although EPA has used these data, it has also flagged certain data points to note any discrepancies, such as the analytical method not being an EPA

approved method or if there are questions pertaining to the QA/QC data. These flags may be used in the future to exclude certain data points. There are additional data submissions that EPA did not use in calculating today's revised limitations and standards because the Agency has not completed verifying that such data meets EPA's criteria for inclusion. Although not used, these data are included in the record for this document for purposes of public comment. EPA has fully explained how it will calculate long-term averages and variability factors for the final limitations and standards so commenters may determine the effect these data would have if included in the data base for the final rule. EPA will continue to contact facilities where major components were missing from the data submittal and will consider including these additional data sets now available in the record in the development of the limitations and standards for the final rule to the extent they meet EPA standards for inclusion.

EPA is using long-term monitoring data (
i.e.,
data used for compliance monitoring) from 31 General Metals facilities, 1 Metal Finishing Job Shop, 4 Zinc Platers, 2 Printed Wiring Boards, 3 SFF facilities, 3 Oily Wastes facilities, and 2 Shipbuilding Dry Docks. EPA is also using industry-submitted paired influent/effluent data from 26 General Metals facilities, 8 Metal Finishing Job Shops, 2 Zinc Platers, and one Oily Wastes facility. Data submitted with comments can be found in section 12.2.2 of the public record.

EPA requested data to aid in characterizing the concentrations of pollutants in wastewaters from MP&M processes (
i.e.,
unit operations). In addition to EPA's post-proposal sampling program, described above, EPA received unit operations sampling data for the following unit operations:

• UP 4: Acid Treatment without Chromium

• UP 4R: Acid Treatment without Chromium Rinse

• UP 5: Alkaline Cleaning for Oil Removal

• UP 5R: Alkaline Cleaning for Oil Removal Rinse

• UP 14: Chemical Conversion Coating without Chromium

• UP 16: Chromate Conversion Coating

• UP 16R: Chromate Conversion Coating Rinse

• UP 17: Corrosion Preventative Coating

• UP 17R: Corrosion Preventative Coating Rinse

• UP 24: Electroplating without Chromium or Cyanide

• UP 24R: Electroplating without Chromium or Cyanide Rinse

• UP 27: Grinding

• UP 33: Painting—Immersion (E-Coat)

• UP 83: Acid Pickling Neutralization

• UP 93: Iron Phosphate Conversion Coating

• UP 93R: Iron Phosphate Conversion Coating Rinse

EPA is using this data for two main purposes. First, EPA is using this data to supplement unit operations data used to estimate the pollutant loadings, by subcategory, contained in MP&M wastewaters prior to treatment. As discussed in section III.A of today's document, EPA is making every effort to use subcategory-specific unit operations data instead of estimating loadings by averaging the data by unit operations across subcategories.

Second, EPA is using this data to better define those operations which should be included in EPA's definition of “oily operations” used to differentiate the Oily Wastes Subcategory from the General Metals Subcategory. EPA received many comments on certain unit operations that, as proposed, would cause a facility to fall under the General Metals Subcategory instead of the Oily Wastes Subcategory. Commenters concluded that these unit operations are truly “oily operations” generating wastewater that contains little or no metals and would not be effectively treated using the recommended treatment for the General Metals Subcategory (
i.e.,
Option 2, which includes metal removal via chemical precipitation). Using the data that EPA received and a review of all unit operations data, EPA is considering incorporating into the definition of “oily operations” the following unit operations and any associated rinses (
see
section IV.A for a potential revision to the definition of “oily operations”):

• UP 1: abrasive blasting

• UP 7: alkaline treatment without cyanide;

• UP 11: assembly/disassembly;

• UP 12: tumbling/barrel finishing/mass finishing/vibratory finishing;

• UP 13: burnishing;

• UP 18: electrical discharge machining;

• UP 35: polishing;

• UP 43: thermal cutting;

• UP 44: washing of final products;

• UP 45: welding;

• UP 46OR: wet air pollution control for organic constituents;

• UP 51: bilge water;

• UP 71: adhesive bonding;

• UP 72: calibration; and

• UP-93: iron phosphate conversion coating.

EPA is considering this revision based on the low levels of metals and similarity of wastewater characteristics to other “oily operations,” (
see
section IV of today's document for the potential revised definition of oily operations).

EPA also received data from the American Association of Railroads (AAR) which summarized the current permit limits, treatment-in-place (TIP), and the facilities' measured monthly average and average of daily maximum values for the last year for all known direct discharge railroad line maintenance facilities. More recently, this trade association provided the individual responses to their survey questionnaire. Each railroad line maintenance facility provided one year of long-term monitoring data (
see
section 15.1 of the public record for the AAR surveys). EPA is reviewing alternative options for the Railroad Line Maintenance Subcategory based on this data. See section IX.F of today's document for this discussion.

C. Analytical Method Validation Study and the Total Organics Parameter

In an effort to provide flexibility, EPA proposed three options for meeting limits related to organic chemicals. One option focused on the use of a surrogate parameter, Total Organics Parameter or TOP, to be used for monitoring organic pollutants in MP&M wastewater. In the proposal, the “TOP” consisted of 48 individual organic pollutants. To comply with the TOP limit, as proposed, a facility would monitor for all 48 pollutants (or a lesser number if a waiver was obtained for pollutants not present) and sum the measured values, using the nominal quantitation value for non-detects. As discussed in the proposed rule (66 FR 529), the following TOP analytes do not have approved EPA methods: Benzoic acid, carbon disulfide, 3,6-Dimethylphenanthrene, 2-Isopropylnaphthalene, 1-Methylfluorene, and 2-Methylnaphthalene. In addition, aniline and 1-Methylphenanthrene do not have procedures approved in 40 CFR part 136, but do have procedures that have been validated as attachments to EPA Methods 1625/625. With the exception of Benzoic Acid, EPA has performed a study to validate EPA Analytical Methods 1624B/624 and 1625/625 for these organic pollutants. EPA eliminated benzoic acid because of its low and highly variable recovery using EPA Methods 625 and 1625. Benzoic acid will be deleted from the list of organic pollutants that constitute the Total Organics Parameter.

In order to provide test methods for six additional semivolatile organic

pollutants (aniline, 3,6-dimethylphenanthrene, 2-isopropylnaphthalene, 1-methylfluorene, 2-methylnaphthalene, and 1-methylphenanthrene) and one additional volatile organic pollutant (carbon disulfide) in the MP&M industry final rule, EPA has developed and validated attachments to EPA Methods 624 and 1624B and validated revisions to the existing attachments to EPA Methods 625 and 1625. The attachments and revisions to the attachments are:

• Method 624, Attachment 1: Determination of Additional Volatile Pollutants, January 2001

• Method 625, Attachment 1, Revision A: Determination of Additional Semivolatile Pollutants, January 2001 (Method 625, Attachment 1A)

• Method 1624B, Attachment 1: Determination of Additional Volatile Pollutants, January 2001

• Method 1625B, Attachment 1, Revision A: Determination of Additional Semivolatile Pollutants, January 2001 (Method 1625B, Attachment 1A)

The validation study for each of the above methods attachments involve analyses of MP&M industry wastewater samples collected by EPA and sent to three separate laboratories for analyses by Methods 1624B and 1625B. Apart from the fact that Methods 1624B and 1625B contain analytes that are not found in Methods 624 and 625, the principal differences between these 1600 Series methods and their 600 Series counterparts is that the 1600 Series methods employ isotope dilution quantitation to determine the concentration of many of the target analytes. The concentration of the target analytes are determined using an internal standard quantitation procedure in the corresponding 600 Series methods. As a result, for the purposes of this study, instead of analyzing a sample once by Method 1624B and again by Method 624, it is both possible and practical to perform the analysis of a given sample once for Method 1624B using isotope dilution quantitation and then reprocess the resulting mass spectrometric data using the internal standard procedures employed in Method 624. The same situation applies to Methods 1625B and 625—one analytical run can provide data for both quantitation approaches.

The results of this validation effort have been used to develop method performance criteria for the seven new analytes in the attachments to Methods 1624B, 624, 1625, and 625. These criteria are specific to the use of these methods to demonstrate compliance with the MP&M final rule only. The final report for the study provides criteria for: method sensitivity, calibration linearity, labeled compound recovery (Methods 1624B and 1625), and matrix spike recovery (Methods 624 and 625). The interlaboratory study results and the revised attachments are included in the MP&M rulemaking record. See section VI.B. of today's document for a discussion on alternative approaches to calculating the TOP limit.

III. Revisions & Corrections to the Cost & Loadings Model

Based on proposal comments, EPA has revised several aspects of the Cost & Loadings Model used to develop estimates of compliance costs and pollutant loads. This section discusses the changes in methodology and corrections to the model and database for this document including: (1) Subcategorization of unit operations data; (2) pollutant specific revisions to the loadings and removals; (3) corrections to the coding in the model; (4) re-imputation of missing wastewater flows; and (5) several other issues on which EPA is soliciting comment. Section VI of today's document provides a more detailed discussion of the results of the re-analysis using the revised Cost & Loadings Model (and the revised associated input databases).

A. Subcategorization of Facilities and Unit Operations Data

This section discusses changes being considered to EPA's subcategorization scheme as well as changes to the way in which EPA is using the data that characterizes MP&M operations (
i.e.,
unit operations).

1. Changes in EPA's Subcategorization Scheme

In the proposal, EPA solicited comment on the proposed subcategorization scheme. Based on the comments received, EPA is considering placing Printed Wiring Board (PWB) facilities and Printed Wiring Board job shops in the same subcategory: Printed Wiring Board. At proposal, EPA placed the PWB job shops in the Metal Finishing Job Shops Subcategory based on the special economic conditions of job shops. However, information submitted by commenters indicates that PWB job shops are much more similar to PWB facilities than to metal finishing job shops when considering their wastewater characteristics and operations. For all analyses supporting today's document, EPA has placed the Printed Wiring Board job shops in the Printed Wiring Board Subcategory.

In addition, based on comments, EPA has reviewed the unit operations of Printed Wiring Assembly facilities and has determined that they are most similar to the facilities in the General Metals Subcategory. Printed wiring assembly facilities do not manufacture printed circuit boards, but do attach circuit boards to other structures. Therefore, they do not perform the operations typical of a printed wiring board facility (
e.g.,
applying photoresist, etching of the board, or stripping). EPA concluded that most printed wiring assembly facilities in the MP&M database were placed in the General Metals Subcategory for proposal. For this document, EPA has confirmed that all printed wiring assembly facilities are identified as General Metals facilities. Unless new information leads EPA to reconsider this determination, EPA will address the codified language for the applicability of the General Metals Subcategory of the final rule to reflect the inclusion of the printed wiring assembly facilities in the subcategory.

EPA received comments concerning the definition for “oily operations” used in the applicability statement of the Oily Wastes Subcategory. Commenters provided data on several MP&M unit operations which were not part of the “oily operations” definition in the proposed rule. The data show that there are low levels of metals in these unit operations. Based on the data received and a review of other unit operations containing only low concentrations of metals, EPA is considering whether to revise the proposed definition of “oily operations” used to define the Oily Wastes Subcategory (
see
sections II.B and IV.A). This change would result in the reclassification of several facilities to the Oily Waste Subcategory that were originally classified in the General Metals Subcategory at proposal (
see
section VII of today's document for the number of facilities now estimated in each subcategory).

Finally, EPA is considering whether to subcategorize or segment metal finishing zinc platers. EPA uses the term “zinc platers” to describe facilities where over 95% of their wastewaters are generated from zinc electroplating operations. These facilities typically do not perform copper, nickel, or chrome electroplating. However, most of these facilities follow their plating lines with chromium conversion coating lines. Currently, zinc platers can be found in the Metal Finishing Job Shops Subcategory (
i.e.,
job shop zinc platers) and the General Metals Subcategory (
i.e.,
captive shop zinc platers). The wastewater characteristics of zinc platers are different from other facilities

in these two subcategories, particularly with respect to their concentrations of zinc. Where non-zinc platers may have concentrations of 10-90 mg/l zinc in their wastewater prior to treatment, zinc platers have concentrations from 100-800 mg/l zinc in their wastewater prior to treatment. However, zinc platers have very low concentrations of other pollutants as compared to non-zinc platers. Therefore, EPA is considering subcategorizing zinc platers by either creating a separate subcategory for all zinc platers, or creating a segment within each of the two affected subcategories. EPA is also considering retaining the current structure. The use of a segment would allow for a separate numerical limitation for zinc for zinc platers while providing ease of implementation as it would allow them to remain in their appropriate current subcategory (
i.e.,
Metal Finishing Job Shops or General Metals). EPA is also considering no change to the current subcategorization scheme but adopting a new zinc limit that represents zinc levels achievable by zinc platers operating BAT treatment systems. In this case, EPA would use data from the sampling of zinc platers to set the zinc limit in the Metal Finishing Job Shops and General Metals subcateogries. EPA concluded that this approach would cause the least confusion for permit writers and be the easiest to implement; however, this approach would allow discharge of additional pounds of zinc to the environment from non-zinc platers in the current subcategories (
see
Table III.A-1). These additional pounds of zinc would have corresponding low pound-equivalents due to the low toxicity weighting factor (0.047) for zinc.

Table III.A-1.—Incremental Pounds of Zinc Discharged to the Environment When Using Only Zinc Plater Data for Setting the Zinc Limits for the Metal Finishing Job Shops and General Metals Subcategories

Discharger status
Facility type
Number of facilities
Pounds
Pound-equivalents

Indirect
General Metals
10,787
8,200
385

General Metals (> 1 MGY)
1

2,055
7,491
352

Metal Finishing Job Shops
1,165
1,895
89

Direct
General Metals
1,500
9,754
458

Metal Finishing Job Shops
24
101
5

1
Note: MGY: Million Gallons per Year

EPA solicits comment on whether: (1) Zinc platers should be in their own subcategory; (2) a segment within existing subcategories; or (3) no change in subcategorization with a zinc limitation that is achievable by zinc platers. EPA also solicits comment on the burden to permit writers and control authorities associated with each approach.

2. Subcategorization of Unit Operation Data

In the Cost & Loadings Model used for the proposed rule, EPA averaged all data for a specific unit operation (
e.g.,
UP23—electroplating with cyanide) regardless of the subcategory of the facility from which the data was collected. Therefore, cyanide concentrations from a metal finishing job shop's UP23 were averaged with cyanide concentrations from a printed wiring board's UP23, and with cyanide concentrations from a general metals facility's UP23. EPA received many comments demonstrating that the concentrations of cyanide in electroplating varied greatly between subcategories, and most importantly between metal finishing job shops and printed wiring boards. Similarly, EPA received comments that the concentration of copper and tin differed widely between printed wiring board facilities and other subcategories. Therefore, for this analysis EPA is applying concentration data from unit operations by subcategory to the extent possible.

EPA has segregated the existing unit operations concentration data, including data used for proposal and newly collected data, by subcategory. EPA performed post-proposal sampling (
see
section II.A) of many printed wiring board unit operations in an effort to distinguish printed wiring board data from other MP&M subcategories with metal-bearing wastewater. For example, at proposal EPA used an average cyanide concentration of 27,959 mg/l for UP23 for all metal-bearing subcategories; however, EPA has revised the Cost & Loadings Model to use a cyanide concentration for UP23 of 5,200 mg/l for metal finishing jobs shops and 430 mg/l for printed wiring boards based on data obtained from these operations (
see
section III.B.1).

In addition to segregating the unit operations data by subcategory, EPA has segregated the unit operations for the “zinc plater” segment of the Metal Finishing Job Shops and General Metals subcategories. Therefore, the unit operations (raw wastewater) of a model site that is a zinc plater would be credited with the appropriate level (
i.e.,
higher level) of zinc and appropriate levels (
i.e.,
very low or non-detect) of other pollutants.

EPA has also collected unit operation data that is specific to the steel forming and finishing subcategory so that modeled pollutant loadings will better reflect wastewater characteristics at those sites.

Finally, EPA received comment concerning the variability of the wastewaters sampled to represent the “testing” unit operation. EPA defines the testing unit operation as the application of thermal, electrical, mechanical, hydraulic, or other energy to determine the suitability or functionality of a part, assembly or complete unit. Commenters are concerned that wastewater concentrations from testing of one type (
e.g.,
automotive radiators) does not represent the same wastewater characteristics as testing of another type (
e.g.,
aircraft engines). EPA is considering whether or not to further divide the testing unit operation, particularly for the General Metals Subcategory, by industry sector or testing type (
e.g.,
hydrostatic, dye penetrant, ultrasonic, magnetic flux). EPA data show automotive radiator testing molybdenum, fluoride, and vanadium concentrations are 774 mg/l, 0 mg/l (not measured) and 0.004 mg/L respectively, while aircraft parts testing molybdenum, fluoride, and vanadium concentrations are 0.271 mg/l, 49,000 mg/l, and 215 mg/l respectively. EPA solicits comment on whether or not to subdivide the testing unit operation and ways to appropriately divide the Agency's data from this unit operation.

The methodology for subcategorization of unit operation concentrations and a discussion of

remaining data transfers from one subcategory to another are described in a memorandum in the public record, entitled “ MP&M Pollutant Loadings Subcategory-Specific Data,” section 16.7, DCN 16759. EPA solicits comments on this approach.

B. Pollutant Specific Revisions to Loadings and Removals

EPA received comment on several pollutant-specific issues related to the pollutant loadings and removals generated by EPA's Cost & Loadings Model. In some cases, commenters questioned results from a specific sampling episode. For example some commenters stated that the misclassification of a cyanide electroplating sampling point led to an overestimation of cyanide pollutant loadings and removals. In other cases, commenters raised more general issues, such as the percent removal value assigned to boron (at proposal boron was set equal to the long term average (LTA) for boron, not using a percent removal) in the Cost & Loadings Model. EPA solicits comment on how EPA has tentatively addressed these issues. EPA is also reviewing several data points that commenters concluded to be “outliers.” In several cases EPA has addressed these issues and in other cases, due to the need to work with the facility in question, EPA is working toward resolving them for the final rule. Below is a discussion of the revisions being considered regarding the most prominent of the pollutant-specific issues: cyanide, tin, copper, sulfide, and boron. A detailed summary of all the pollutant-specific issues under review may be found in a memorandum entitled, “MP&M Pollutant Loadings Methodology Changes from Proposal” in the public record for this document, section 16.7, DCN 16764. EPA notes that the pollutant loadings and removals for the final rule will reflect the addition of EPA and appropriate industry submitted unit operations data to the model. (
see
section IV of today's document for a discussion on EPA's current views on possible changes to pollutants selected for regulation).

1. Cyanide

The major issue regarding cyanide pollutant loadings raised by commenters involves the misidentification of a single sampling point. Prior to proposal, EPA sampled at one facility what it concluded was cyanide electroplating rinse water (
i.e.,
UP23R). For the proposal, that data was averaged with other cyanide concentrations for the same unit operation (UP23R) to obtain an average cyanide concentration for use in the Cost & Loadings Model for that unit operation. Although the concentration of cyanide was considerably higher than other facility data for the same unit operation, a check of the site report, which had been reviewed by the facility, verified that sample point as a rinse water. Based on comments received and additional follow-up discussion with the sampled site, EPA now has determined that the actual sample was taken from a drag-out tank that follows the cyanide electroplating bath and that the drag-out tank water is recycled. Therefore, the concentration of cyanide in that tank is not characteristic of cyanide electroplating rinse water (
i.e.,
UP23R) and EPA has removed this cyanide concentration (and concentrations of all other pollutants from that sampling point) from the electroplating with cyanide rinse unit operation (UP23R) and has reclassified it as a drag-out rinse that is recycled (UP23RDO). This change has a significant effect on the average cyanide concentration used for the proposal in the cost and loadings model for that unit operation and the resulting cyanide pollutant concentration levels (5,042 mg/l to 3.6 mg/l for general metals). Further, EPA is now considering using unit operations concentration data on a subcategory-specific basis for the final rule (
see
section III.A.2 of today's document). The cyanide data point discussed here was taken at a general metals facility. Therefore, this data point would no longer affect the cyanide loadings for the metal finishing job shops, printed wiring board, non-chromium anodizing, or steel forming and finishing subcategories for the final rule. Following this approach, the current estimated cyanide concentrations for cyanide electroplating rinse (UP23R) are as follows: 58.8 mg/l for metal finishing job shops, 22.02 mg/l for printed wiring board, 22.02 mg/l for non-chromium anodizing, and 22.02 mg/l for steel forming and finishing. This document reflects these concentrations. See section VII of today's document for a discussion on the overall change in pollutant loadings and removals due to revisions to the Cost & Loadings Model.

2. Tin

The major issue regarding tin concentrations raised by commenters in the Cost & Loadings model involves the misclassification of a sampled unit operation containing a large concentration of tin. Prior to proposal, EPA sampled a unit operation that it classified as UP4R (acid treatment without chromium rinse). However, based on comment and subsequent review of the sampling episode report, EPA has concluded that this unit operation is different from UP4R. This unit operation involved the use of a catalyst solution for electroless plating operations and did not fit in any of EPA's current unit operation descriptions. Therefore, EPA created a new unit operation for electroless plating catalyst solutions (UP87) and assigned the data for tin and all other pollutants associated with that particular sampling point to the new unit operation.

EPA estimated tin concentrations for acid treatment without chromium rinse (UP4R) across all subcategories in the proposal at 256.2 mg/L. The current estimated tin concentrations for UP4R are as follows: 1.97 mg/l for metal finishing job shops, 0.0204 mg/l for printed wiring board, 0.0444 mg/L for general metals, and 0.0432 mg/L for zinc platers. This document reflects these revised concentrations. See section VII of today's document for a discussion on the overall change in pollutant loadings and removals due to revisions to the Cost & Loadings Model.

3. Copper

The factors discussed above related to cyanide and tin also would result in changes in pollutant loadings for copper. When EPA revised the cyanide and tin concentrations for those two sampling points, it also revised the concentrations for all pollutants associated with those sampling points, including copper. Copper loadings are also largely affected by the subcategorization of unit operations data and EPA's post-proposal sampling of three additional printed wiring board facilities. In EPA's view, the copper loadings for non-printed wiring board facilities would be reduced through the use of subcategory-specific unit operations data. Further EPA has concluded that the copper loadings for printed wiring board facilities would be more reflective of those facilities due to the incorporation of additional printed wiring board sampling data.

EPA estimated copper concentrations for acid treatment without chromium rinse (UP4R) across all subcategories in the proposal at 52.85 mg/L. The current estimated copper concentrations for UP4R are as follows: 7.97 mg/l for metal finishing job shops, 58.97 mg/l for printed wiring board, 9.49 mg/L for general metals, and 7.97 mg/L for zinc platers. This document reflects these revised concentrations. See section VII of today's document for a discussion on the overall change in pollutant loadings

and removals due to revisions to the Cost & Loadings Model.

4. Sulfide

EPA received many comments concerning EPA's estimate of pollutant removals for total sulfide and EPA's proposal to regulate total sulfide. Commenters stated that the pollutant removals associated with total sulfide were inflated due to the analytical method EPA used to test for total sulfide. Commenters concluded that the method used (EPA Method 376.1) may yield erroneous results because of matrix interference (i.e., erroneous analytical results for the pollutant of concern due to certain substances present in the sample). This may result in higher reported sulfide concentrations than what is actually in the wastewater. In addition, many of the data points used for total sulfide were transferred from data for the Oily Wastes Subcategory to other subcategories. Therefore, as discussed in section II.A of today's document, EPA is now using two additional methods (EPA Method 376.2 and Standard Method 4500-S
−
2
[E], 18th edition) to test for total sulfide. For the purposes of establishing unit operations concentrations for a specific sampling point for the Cost & Loadings Model for the NODA analyses, EPA averaged the data from Methods 376.2 and 4500-S-
−2
(E). For the final rule EPA currently intends to follow the recommendations in the memorandum titled, “Evaluation of Sulfide Results for Metal Products and Machinery Samples Analyzed by MCAWW Method 376.1, MCAWW Method 376.2, and Standard Method 4500-S
−
2
(E)” (
see
section 16.2, DCN 16941). The memorandum's recommendations are specific for unit operations, influent, and effluent concentration data.

EPA is considering the effects of these recommendations on loadings and solicits comments on this analysis. EPA is also now using subcategory-specific unit operations data, so that in all cases total sulfide concentrations would not be transferred from oil-bearing subcategories to metal-bearing subcategories. If no sulfide concentration was identified for unit operations within a subcategory, EPA set the sulfide concentration equal to zero for today's document, and is considering doing the same in the analysis for the final rule.

5. Boron

Although EPA did not propose to regulate boron, many commenters expressed concern with EPA's estimates of boron pollutant removals. Commenters state that boron is not removed in chemical precipitation systems and any removal is an artifact of the database. EPA has revisited the analysis regarding the removal of boron in chemical precipitation systems and has concluded that boron shows widely variable removals in two BAT treatment systems and is not removed at all (or has negative removals) in the remaining three BAT treatment systems (
see
section 16.7, DCN 16758). EPA has concluded that, in most cases at MP&M facilities, boron is in the dissolved anionic form (as borate) and cannot be removed by chemical precipitation.

For the purposes of estimating boron removals for today's document for subcategories where EPA is using chemical precipitation as the basis for limitations, EPA has made a change to the methodology. For today's document, EPA has set the pollutant removals for boron equal to zero. Therefore, EPA is not claiming any removal for boron from chemical precipitation systems.

EPA also considered a more site-specific approach where EPA would apply the boron removal percentage from a particular EPA sampling episode to all model facilities with similar characteristics to the sampled facility. For example, commenters stated that one reason EPA's boron removals were inflated was because removals were based on a facility that also performs porcelain enameling, where the wastewaters are commingled for treatment. The commenters stated that the porcelain frit was the cause for the relatively high boron removals (i.e., the boron is in solid form and can be removed by gravity separation) compared to facilities that are not also performing porcelain enameling. Therefore, in this example, EPA considered applying the boron removal based on the sampled facility with the porcelain enameling and MP&M wastewaters only to other model facilities in EPA's database that also conduct porcelain enameling operations. EPA reviewed all sites in EPA's questionnaire database and found six survey sites that reported being covered by the Porcelain Enameling effluent guidelines. Of these six sites only one site was discharging wastewater from MP&M and porcelain enameling operations and the percentage of wastewater from porcelain enameling operations was less than two percent of their wastewater volume. It is likely that the national estimate of boron removals using this approach, relative to the removals for other pollutants, would be close to zero. EPA solicits comment on the revised results and which approach EPA should use for the final rule to estimate boron removals.

EPA intends to conduct further review of boron removals in other treatment systems, such as Dissolved Air Flotation (DAF). DAF is currently the basis for the limitations in the Shipbuilding Dry Dock and Railroad Line Maintenance Subcategories. EPA has data from the MP&M database as well as data from other previous regulations indicating positive removals of boron from DAF systems. EPA will review the form of the boron present in wastewater from these subcategories (e.g., dissolved or insoluble) and examine the mechanism for removal.

EPA will also perform an assessment for the final rule investigating molybdenum removals via chemical precipitation similar to that used for boron. EPA may determine from this analysis that: (1) Molybdenum is present in MP&M wastewaters as a dissolved form which is not removable by chemical precipitation; or (2) there is a low level of incidental molybdenum removal for use in the Cost & Loads Model. There may be incidental removals when molybdenum adheres to oily wastewaters that are removed in the oil water separation step or other treatment steps (e.g., flocculation). For the analyses performed for today's document, EPA is using the average effluent concentration achieved for molybdenum by EPA sampled facilities. (
see
section IV of today's document for a discussion on molybdenum as a pollutant selected for regulation). EPA solicits comment on molybdenum being removed through oil water separation step or other treatment steps (e.g., flocculation).

C. Stream Code Corrections

This section describes how EPA intends to revise several parts of the computer format of the model and data entry corrections EPA will make based on comments received regarding the Cost & Loadings Model. All revisions and corrections discussed in this section, affecting approximately 5% of the stream codes, have been incorporated into the analyses supporting today's document.

There were two cases where EPA's Cost & Loadings Model did not correctly link unit operations (UP) “extender” codes in the stream identification field of the database. Extender codes are used to indicate a rinse (“R”) or can be used to indicate the presence of multiple lines. For example, if the facility had 3 different acid treatment without chromium rinse lines, the lines would be labeled UP 04R-1, 04R-2, 04R-3. When the model did not correctly link

with these codes it led to the mis-assignment of each stream for the purposes of determining whether or not the stream should receive credit for having treatment-in-place (TIP). Therefore, at proposal there were a number of rinses or multiple lines that were not given proper credit for TIP.

Another example is where a site's questionnaire indicated that UP04 (acid treatment bath without chromium) goes to treatment, but did not say whether or not UP04R (acid treatment rinse without chromium) went to treatment. For the proposal cost and load analysis, TIP credit was given for UP04, but not for UP04R. EPA has corrected the model used for today's document. In another example, a site's questionnaire indicated UP04R goes to treatment, but when multiple lines (UP04R-1, -2, -3) are present, TIP credit did not get conveyed in the proposal cost and loads analysis to the streams labeled UP04R-1, -2, -3. EPA notes that less than three percent of all streams required a change in TIP assignment due to this error.

Similarly, when converting from numeric to text format for use in running the Cost & Loadings Model, some streams converted as UP1R-1 and UP4R-1 instead of UP01R-1 and UP04R-1. This caused a mismatch in the model databases and those streams were not given proper TIP credit. EPA has corrected the model used for today's document.

EPA has also identified a few data entry errors that were limited in scope, but do affect the output of the Cost & Loadings Model. In one case, the facility completed an erroneous page in their questionnaire for the treatment unit at their facility (e.g., equalization/neutralization instead of chemical precipitation). In correcting this error, the reviewer did not transfer all of the affected unit operations from the erroneous page to new treatment unit page, and therefore, some unit operations did not get entered and did not receive TIP credit. EPA has corrected the model used for today's document.

In another case, the facility completed the unit operation page of their questionnaire but did not indicate to which treatment unit the unit operation discharged. Therefore, TIP credit was not given for that unit operation. Upon further review of these streams and comparison to treatment diagrams (which indicated to which treatment units these streams discharged), a correction was made to the data entry and TIP credit was given. EPA has carefully reviewed questionnaires for all sites where full or partial TIP credit was not given, and has corrected the model used for today's document, accordingly (
see
section III.E).

D. Change in Imputed Flows

EPA uses wastestream-specific flow (not total facility flow) and production information in the Cost & Loadings Model. A number of questionnaires were submitted without data for flow or production related to an individual wastestream. In some instances EPA contacted the facility to gather the information. If the data was not available or if EPA did not contact the facility, EPA imputed data using data from similar facilities in the questionnaire database. The 1,003 facilities in the database had 17,424 different lines (i.e., tanks), of which EPA imputed values for 6,129 lines at 797 facilities. These imputed values included production and/or production normalized flows (PNFs) for most municipality surveys, because the surveys did not request this information from them. This section describes the changes in the data and imputed values from the proposal. This section also describes some changes that EPA is considering for the final rule.

Commenters stated their concerns regarding several large flow values that were created through imputation. Commenters noted that in these cases the flow for the wastestream, when added with all other streams at the facility exceeded the facility's reported total flow (including non-MP&M process wastewater). Commenters suggested using a comparison of the summation of a facility's stream flows with the facility's reported total discharge flow as a “reality check.” EPA has used this “reality check” in the imputations for today's document. Each survey requested the total flow information in different ways. Phase I surveys required respondents to report on the total facility flow. Phase II surveys listed three different fields: MP&M Process Water, Process Water, Total Facility Water Use. EPA used the MP&M Process Water value if it was given by the facility. If this value was not given, EPA used the Process Water value. If neither of these values were reported, EPA used the Total Facility Water Use value.

When EPA examined the data before imputing any values, 10 percent of the facilities in the database had the sum of their individual streams exceed the total facility flow. EPA also identified stream flows that appeared to be incorrect. After identifying these inconsistencies, EPA reviewed its hard copies of the surveys to look for any information which would provide more accurate total flows (e.g., perhaps the site wrote in their own units of measure which need to be converted). Most occurrences were with Phase I sites that were surveyed between 1989 and 1990, where previous reviews of the total flow had not been pursued as vigorously as the stream flow information. Based upon its findings, EPA revised the individual stream flows and the total flows in the database. The sum of individual stream flows for a facility were then compared to the reported total flow. EPA scaled back the individual stream flows when the sum of the individual stream flows were greater than the total flow (
see
memorandum titled “Revisions to the Technical Portion of the Imputation Methodology,” section 16.6.1, DCN 27711). EPA also excluded recycle and pollution prevention streams as a basis for imputed values because the flows are often quite large, but usually are not completely discharged. In addition, EPA excluded contract hauling streams from the summation of individual streams, because they would not be included in the facility's reported total discharge flow.

After incorporating those changes into its database, EPA imputed values for individual streams where the flows were unknown. As a check on the imputed values, EPA then compared the total flow at each facility to the sum of all flow values (i.e., imputed and others) for the individual streams at that facility. As a result of these changes, EPA found only 32 facilities (i.e., less than four percent) where the summation of the reported and imputed individual flows exceeded the total reported flows. For these facilities, EPA has either revised the stream flows based upon engineering review or proportionally decreased the imputed flows to be less than the reported total flow.

For the final rule, EPA has determined that further improvements in the imputation strategy may be warranted and solicits comments on its ideas. In the current strategy, EPA assumes that all missing flows correspond to operations that discharge water and thus missing flows have imputed values that are always greater than zero. However, the surveys identified that some unit operations are frequently dry operations. For the final rule, EPA may assign some missing flow values to be zero (i.e., dry).

In addition, while the imputation procedure uses relevant information from similar operations at the facility when it has some reported and some missing values, these similar operations may include several different types of unit operations. In its review of the data, EPA observed that values were often identical between different lines (or

tanks) of the same unit operation and would often differ between unit operations at that facility. Thus, EPA makes every attempt to use relevant information from similar operations at the facility when it has some reported and some missing values, EPA has determined that placing more emphasis on the unit-level operations may be more appropriate in the intra-facility imputations for streams.

When intra-facility information could not be used, the imputation procedure used the median value of all of the lines within a “unit grouping.” Within each unit grouping, EPA combined similar unit operations based upon water usage characteristics and the number of lines associated with each operation. EPA then calculated the median value of the lines for each unit grouping. However, when it examined summary statistics such as the 10th and 90th percentiles for each unit grouping, EPA observed that the production-normalized flows and production were extremely variable within many unit groupings. For the final rule, EPA intends to investigate the causes for this variability for the final rule, and possibly re-define the unit groupings to be more homogeneous.

Also, for the final rule, EPA will consider facility and subcategory effects on the imputed values. As stated above, EPA noted that values within a facility tended to be similar. Thus, a facility with many lines in a particular unit operation would have more influence on the median value than a facility with fewer lines. For the final rule, EPA may consider using a single value from each facility rather than using the values from every line in that unit operation. Also, because it has observed some differences between subcategories with the same unit operation, EPA will investigate whether the imputation procedure should incorporate subcategorization in some way.

In a memorandum in the public record (
see
section 19.2, DCN 36081), EPA has described the current strategy, unit groupings, and assumptions, and indicated the changes that it may incorporate for the final rule. These changes will probably have little or no impact for most facilities. For others, it may increase or decrease the flows of the imputed streams. This may have the effect of lowering pollutant loadings with the inclusion of zero discharge unit operations. EPA solicits comment on the approaches outlined in the memorandum.

E. Changes Considered for Methodology for Treatment-In-Place Credits

For the proposed rule, EPA estimated the baseline pollutant loadings (i.e., pollutant loading prior to compliance with the MP&M regulations) from model facilities based on actual treatment-in-place at those sites based on questionnaire responses. If a model site had no treatment-in-place for their MP&M wastewaters or if a metal-bearing site only had pH adjustment, neutralization or equalization without any mechanism for sludge removal, EPA estimated baseline pollutant loadings based on raw wastewater data from EPA sampling episodes. If a site had some or all of its MP&M wastewater going through a treatment system (BAT system, equivalent, or better), EPA estimated baseline pollutant loadings, for those streams going through the system, based on the long-term average (LTA) effluent concentrations (i.e., design concentrations) from the Metal Finishing effluent guidelines (40 CFR part 433) for pollutants regulated by that regulation (with the exception of cyanide) and based on treatment system specific effluent concentration data (i.e., MP&M LTAs) from EPA sampling episodes for cyanide and the other MP&M pollutants of concern. Commentors raised questions about whether EPA was providing appropriate treatment-in-place credits for certain technologies in the proposal, and this subject is specifically addressed later in this document. In the case where a facility was treating some MP&M wastewaters using its on-site treatment system, but not others, EPA estimated the baseline pollutant loadings for the streams receiving treatment using the treatment-specific effluent concentrations described above and using the raw wastewater data for those streams not going through treatment in the baseline. In the MP&M Costs & Loads Model, such facilities are referred to as having “partial treatment-in-place credit.” The same holds true for facilities that may have a portion of a BAT system, such as alkaline chlorination for cyanide destruction, but do not perform further treatment for metals using chemical precipitation and clarification.

EPA then estimates pollutant loadings for the proposed option for each model site. When estimating the pollutant loadings for the proposed option, EPA assumed the site was meeting the long-term average (LTA) concentrations (i.e., design effluent concentrations) achieved by EPA's sampled MP&M BAT facilities. If a site is performing better at baseline (e.g., microfiltration for solids removal) than required by the MP&M proposed option (e.g., clarification), EPA assumed for the NODA analysis that the site will continue to operate with the superior technology for the EPA proposed option.

EPA calculates the pollutant loads removed by the proposed option as the difference between the pollutant loadings estimated for the proposed option and the pollutant loadings estimate for the baseline. This means that for sites which have treatment-in-place at the baseline that is the same or equivalent to the BAT treatment (i.e., sites with full TIP credit), EPA is claiming very little, if any, additional pollutant removal due to the MP&M regulation. EPA notes that the MP&M regulation may still show significant removals for those facilities that have equivalent “end of pipe” technologies or treatment units (e.g., metal removal via chemical precipitation) but not the BAT pollution prevention technologies (e.g., paint water curtain, counter-current cascade rinsing, machine coolant recycling). For these facilities, the “end of pipe” technologies may be equivalent, but EPA's modeling drastically increase the efficiencies of their system with the increased influent concentrations. For sites that have some MP&M wastewaters receiving treatment in the baseline (i.e., sites with partial TIP credit), the additional pollutant removal EPA is claiming is largely from their untreated streams. Finally, sites with no treatment-in-place or only pH adjustment, neutralization, or equalization without any mechanism to remove sludge (i.e., sites with no TIP credit) are the largest source of the pollutant reductions that EPA estimated for the proposed rule.

The two most prominent issues received in comments regarding treatment-in-place (TIP) credit (with exception of the stream code corrections to the Cost & Loadings Model discussed in section III.C above) dealt with giving TIP credit for alternative technologies, including ultrafiltration, and with EPA's methodology for calculating the baseline load for currently regulated facilities (
see
also section 16.4, DCN 16883).

1. Equivalency of Alternative Technology as BAT

When determining whether or not to provide a site with TIP credit for an existing treatment system, EPA reviewed the site's questionnaire for information to determine if the treatment system was equivalent (or better) than the proposed BAT technology. The proposed BAT technology for existing facilities in the metal-bearing subcategories consists of segregation of chelated wastes, hexavalent chromium reduction, when necessary, cyanide destruction by alkaline chlorination, when necessary,

chemical emulsion breaking for oils removals, incorporation of pollution prevention and water conservation practices, and chemical precipitation (by sodium hydroxide) followed by a lamella slant-plate clarifier and sludge removal.

When determining whether a treatment system was “BAT,” equivalent, or better than BAT for the purposes of determining treatment-in-place credit, EPA assumed that facilities that indicated chemical precipitation systems would also have a clarifier (even when they did not indicate this) and vice versa. However, EPA assumed that sites with metal-bearing wastestreams must have some mechanism for sludge removal to truly be operating a chemical precipitation and clarification system. EPA also assumed for the proposal and today's document that: (1) Facilities operating chemical precipitation followed by microfiltration or membrane to be at least equivalent to BAT; (2) facilities which indicated membranes for solids removal (i.e., microfiltration, reverse osmosis) also had chemical precipitation and are at least equivalent to BAT; and (3) facilities which indicated on their surveys “pH-Adjustment” followed by solids removal (e.g., clarification, membrane, microfiltration but not gravity settling) as if they were operating a chemical precipitation and clarification system for metals removal. EPA gave these facilities TIP credit at least as equivalent to BAT. EPA will investigate for the final rule which types of “pH-Adjustment” with solids removal, including types and amount of treatment chemicals, should be equated with BAT TIP credit or better. EPA solicits comment on this issue. For cyanide destruction systems, at proposal, EPA assumed that BAT was alkaline chlorination. EPA is considering in-process ion exchange for cyanide removal to be equivalent to alkaline chlorination for the final rule (
see
further discussion below). For sludge removal, EPA assumed that facilities with sludge thickening or a filter press had both components in place. In the case of oily wastes, sites with dissolved air flotation or ultrafiltration were considered to be at least equivalent to the BAT of chemical emulsion breaking for oil removal; however sites with only oil skimming were not considered to be BAT for oil removal.

EPA received several comments from facilities that use alternative treatments for metals removals. For example, many sites use ion exchange systems to reclaim gold from gold-cyanide wastestreams. Ion exchange systems have the ability to remove the cyanide from the wastestream to very low levels. Commenters requested that EPA provide TIP credit for use of ion exchange for removal of cyanide. At proposal, EPA did not make this allowance; EPA is considering this change in methodology for the final rule and has given TIP credit for end-of-pipe ion exchange systems for cyanide destruction in today's document and is also considering giving TIP credit for in-process ion exchange for cyanide destruction in the final rule. EPA is also considering giving full TIP credit for ion exchange for metals removals. EPA expects that granting TIP metals credit to plants with ion exchange will lower pollutant removal estimates from today's pollutant removal estimates. EPA requests comment on which alternative technologies, in addition to ion exchange, should be set as equivalent to cyanide destruction and to chemical precipitation followed by clarification.

2. Pollutant Loadings Baseline

As discussed above, EPA provided credit for achieving the long-term average concentrations of the Metal Finishing rule and the EPA BAT long-term average concentrations for facilities that received TIP credit, regardless of whether or not they are currently covered under the Metal Finishing (40 CFR part 433) or Electroplating (40 CFR part 413) effluent guidelines. However, commenters requested that EPA give baseline part 413 or part 433 limits credit to all facilities currently covered under these existing effluent guidelines even when their questionnaires indicate that there is no BAT TIP. Commenters argue that even without any indication of MP&M BAT TIP, these facilities must be meeting their limits under the existing regulations or else there would be large numbers of facilities in violation of their compliance requirements.

In an effort to address this issue, EPA has performed a sensitivity analysis on the baseline pollutant loadings (“Baseline 413/433 Analysis”) for today's document. In this analysis, EPA assumed that all sites currently regulated by part 413 and/or part 433 meet their existing limits at the point of compliance regardless of the treatment they have in place. EPA used the monthly average limits from the part 413 and part 433 regulations to estimate site-specific baseline pollutant loadings. EPA performed this analysis for all direct and indirect discharging facilities currently regulated by part 413 and/or part 433 in the following subcategories: General Metals, Metal Finishing Job Shops, Printed Wiring Board, Non-Chromium Anodizing, and Zinc Plater. EPA also performed an additional analysis to estimate the revised baseline for sites that would likely be meeting local limits equivalent to the part 433 limits. In the first baseline sensitivity analysis, EPA applied the following rules:

• If the facility is currently covered by part 413 and not by part 433, the effluent wastewater concentrations for cadmium, cyanide, chromium, copper, nickel, lead and zinc were set equal to the part 413 monthly average limits and the concentrations for other MP&M pollutants of concern remain as they were set in the standard Cost & Loadings Model, described earlier in this section.

• If the facility is covered by part 433 or by both part 413 and part 433, the effluent wastewater concentrations for the pollutants mentioned above (with the additional of silver) were set equal to the part 433 monthly average limits and the concentrations for other MP&M pollutants of concern remain as they were set in the standard Cost & Loadings Model, described earlier in this section.

• If the facility is not covered by either part 413 and/or part 433, the effluent wastewater concentrations remain as they were set in the standard Cost & Loadings Model, described earlier in this section.

In the additional baseline sensitivity analysis EPA used the concentration from the part 433 monthly average limits to estimate the baseline pollutant removals for cadmium, cyanide, chromium, copper, nickel, lead and zinc for sites that are in the above mentioned subcategories that are not currently covered by either part 413 and part 433 (i.e., sites meeting local limits in the General Metals and Zinc Plater subcategories) and used the concentrations for other MP&M pollutants of concern as they were set in the standard Cost & Loadings Model, described earlier in this section. This way, EPA can evaluate those facilities that are currently regulated by national effluent guidelines separately from those that are not.

Table III.E-1 provides EPA's national estimates of facilities that are solely regulated under the Electroplating (40 CFR part 413) regulations, or solely regulated under the Metal Finishing (40 CFR part 433) regulations, or regulated by both regulations using the combined wastestream formula. EPA solicits comments on these estimates.

Table III.E-1: National Estimates of Facilities Regulated Under the MP&M NODA, Electroplating ELGs (40 CFR Part 413), Metal Finishing ELGs (40 CFR Part 433), or Both 40 CFR Part 413 and 40 CFR Part 433.

MP&M Subcategory
a

National estimate of facilities covered under MP&M NODA
Direct
Indirect
National estimate of facilities covered only under 40 CFR Part 413
Direct
Indirect
National estimate of facilities covered only under 40 CFR Part 433
Direct
Indirect
National estimate of facilities covered under both 40 CFR Parts 413 and 433
Direct
Indirect

General Metals (GM)
b
,
c

1,500
2,055

91
e

286
534
3,538
68
395

Metal Finishing Job Shops (MFJS)
d

24
1,165
0
278
12
444
12
162

Printed Wiring Board
4
840
0
354
4
122
0
304

Zinc Platers (GM)
21
332
0
62
9
210
12
0

Zinc Platers (MFJS)
0
105
0
36
0
12
0
68

Non-Chromium Anodizing
35
0
0
0
24
19
0
0

Steel Forming and Finishing
41
112
0
4
13
23
0
0

Oily Wastes
c

2,749
288
0
6
16
329
0
0

TOTAL
4,374
4,897
91
1,026
612
4,697
92
929

a
EPA uses the term “zinc platers” to describe facilities where over 95% of their wastewaters are generated from zinc electroplating operations (
see
section III.A.1)

b
These national estimates of General Metals facilities do not include Zinc Platers.

c
The MP&M NODA national estimates include the General Metals and Oily Wastes flow cut-offs (1 MGY and 2 MGY, respectively) while the remaining national estimates for these subcategories do not.

d
These national estimates of Metal Finishing Job Shops do not include Zinc Platers.

e
These sites have both direct and indirect discharges but indicated coverage under part 413 in their survey response.

The results of the two “Baseline 413/433 Sensitivity Analyses” are presented by subcategory in Table III.E-2 below. The results are presented as pollutant removals in pound-equivalents removed per year by subcategory. EPA has estimated pollutant loadings/removals but did not estimate analogous changes in the compliance cost estimates. If this methodology is incorporated into the Cost & Loads Model for the final rule, EPA will provide pollutant removals, compliance costs, cost-effectiveness, economic impacts, and environmental benefits using this analysis. EPA solicits comment on the Baseline 413/433 Sensitivity Analyses and any other possible approaches to address the issue of baseline loadings for facilities currently covered by the Metal Finishing or Electroplating effluent guidelines. In addition, EPA solicits comment on the use of the monthly average limit from part 413 and/or part 433 as opposed to using the long-term average concentration (
see
discussion of rationale below as part of the discussion on the low concentration analysis).

Table III.E-2: Results of “Baseline 413/433” Sensitivity Analyses

MP&M Subcategory

MP&M NODA Removals
(lb-eq/yr)

Direct
Indirect

Removals with change in baseline loads (lb-eq/year)
1

Direct
Indirect

Removals with change in baseline loads (lb-eq/year)
2

Direct
Indirect

General Metals (GM)
996,741
1,240,219
485,495
728,775
431,921
273,234

Metal Finishing Job Shops (MFJS)
1,652
93,190
1,282
35,550
1,282
32,130

Printed Wiring Board
186
153,653
186
63,227
186
41,832

Zinc Platers
937
123,210
160
19,414
160
19,414

Non-Chromium Anodizing
2,392,735
NA
2,387,268
NA
2,387,243
NA

1
This analysis only changes the baseline for facilities currently regulated under part 413/433.

2
This analysis changes the baseline for all sites, regulated and unregulated. NA—not applicable, EPA did not propose MP&M regulations for Non-Chromium Anodizing

EPA also received comment regarding facilities with low concentration raw wastewater characteristics that do not have treatment-in-place (TIP) for some or all of the their wastewater. Commenters state that such facilities do not have TIP because the pollutant loadings in their wastewaters are low enough to meet their current local limits or the Metal Finishing or Electroplating limits without end-of-pipe treatment. EPA's sampling program focused on facilities with TIP and these facilities may have wastewaters with significantly higher concentrations of pollutants than facilities with no TIP. EPA is considering segmenting these “low concentration” facilities in the Cost & Loadings Model for the final rule so that more representative raw wastewater concentrations may be applied to those facilities. Therefore, EPA is soliciting comment on this approach and concentration data at the unit operation level from these “low concentration” facilities, as well as other possible approaches. EPA notes that several of these “low concentration” facilities may now fall under the Oily Wastes Subcategory due to the change in the definition of “oily operations” being considered by EPA for the final rule. Facilities in the Oily Wastes Subcategory are not regulated for metals and have pollutant loadings that are specific to their subcategory.

EPA has performed a sensitivity analysis to identify the potential effect of segmenting the “low concentration” facilities in the General Metals, Metal Finishing Job Shops, Printed Wiring Board, Non-Chromium Anodizing, and Zinc Plater subcategories. In this sensitivity analysis, EPA substituted the Electroplating (40 CFR part 413) or

Metal Finishing (40 CFR part 433) monthly average limitations, as appropriate, for unit operation concentrations found in the Cost & Loadings Model for facilities with no treatment in-place. For facilities that indicated coverage under the part 413 regulations in their survey questionnaire, EPA used the limitations from part 413. For facilities that indicated coverage under the part 433 regulations or coverage under both part 413 and part 433, EPA used the limitations from part 433. For facilities that indicated no coverage by a national effluent guideline or coverage by another category's effluent guideline, EPA assumed these facilities would have local limitations equivalent to the limitations of the part 433 regulation and, therefore, used the limitations from part 433.

EPA used the monthly average limitations instead of the long-term effluent concentration (
i.e.
, design concentration) because the Agency concluded that it may be more appropriate as a facility with no treatment in-place is not targeting a design concentration (
i.e.
, there is no treatment system to design). EPA concluded that a facility is likely to use the monthly average as a determining factor in deciding whether the installation of treatment is necessary at their site. If the facility's discharge levels fall below the monthly average limit, EPA concluded that the facility is unlikely to expend the resources to install treatment. EPA's use of the monthly average limits from the part 413 and part 433 regulations results in higher estimates of baseline loadings for this sensitivity analysis than if EPA had used the part 413 and part 433 LTAs (
see
section 16.5.1, DCN 17802 for a comparison of part 413 and part 433 Limits and LTAs). EPA solicits comment on the use of the monthly average limit in the “low concentration” sensitivity analysis and in the “Baseline 413/433” sensitivity analysis discussed earlier in this section.

The results of this “low concentration” sensitivity analysis are given, below, in Table III.E-3. EPA solicits comment on the results of this sensitivity analysis for both direct and indirect discharge facilities and if this approach should be applied in the final rule. EPA also solicits comment on other possible approaches to address those facilities with low concentration raw wastewater characteristics and do not have treatment-in-place (TIP) for some or all of the their wastewater.

Table III.E-3: Results of “Low Concentration” Sensitivity Analysis

MP&M Subcategory

MP&M NODA Removals
(lb-eq/yr)

Direct
Indirect

Removals using the “Low Concentration” Analysis
(lb-eq/yr)

Direct
Indirect

General Metals (GM)
996,741
1,240,219
908,473
643,427

Metal Finishing Job Shops (MFJS)
1,652
93,190
1,652
54,135

Printed Wiring Board
186
153,653
186
148,742

Zinc Platers
937
123,210
335
31,286

Non-Chromium Anodizing
2,392,735
NA
2,387,268
NA

F. Revisions to the Cost Modules

In addition to the changes to the Cost & Loadings Model that affect the estimates of pollutant loadings and reductions, EPA has also revised several aspects of the costing portion of the model (“cost modules”). EPA has included explicit costs for increased analytical monitoring, incorporated the revised long-term average concentrations, and made several minor corrections to various cost modules. EPA is also considering the addition of a sand filter to the BAT technology option. All changes to the cost modules are fully described in a memorandum entitled, “Cost Model Changes Incorporated into the MP&M Design and Cost Model Since Proposal,” section 16.6.1 of the public record, DCN 16741.

1. Addition of Monitoring Costs

As discussed in the proposal (66 FR 478), EPA assumed that facilities meeting local limitations or national effluent guidelines and pretreatment standards will already incur monitoring costs. EPA did not include monitoring costs in the estimates of operating and maintenance costs for the proposal and solicited comments on that approach. EPA received many comments indicating that EPA needed to include monitoring costs as the proposed MP&M rule regulates several additional pollutants (e.g., tin, sulfide and lead) than previous applicable effluent guidelines. EPA is planning to incorporate monitoring costs into the cost modules for the final rule and has done so for the analyses presented in today's document. However, EPA concluded that the estimate used for today's document is conservative (i.e., potentially over-costed) as it applies an annual monitoring cost of $13,400 for all model sites; however, sulfide, tin, and/or lead are not proposed to be regulated in some subcategories (e.g., tin, lead, and sulfide were not proposed to be regulated for railroad line maintenance facilities or shipbuilding dry docks and tin and lead were not proposed for oily wastes facilities). For the final rule, EPA may apply the pollutant-specific additional monitoring costs to facilities in subcategories with proposed limits for tin, sulfide, and lead, as appropriate (e.g., if sulfide is not regulated in the metal-bearing subcategories, no cost for sulfide monitoring will be included at those facilities). EPA currently estimates the pollutant-specific additional annual cost of quick turn-around sample analysis for lead (by graphite furnace) to be approximately $2,500; for tin to be approximately $4,700; and for sulfide to be approximately $6,200 (
see
memorandum entitled, “Incremental Monitoring and Analytical Costs at MP&M Facilities,” section 16.6.1 of the public record, DCN 16733 for a discussion on the basis of this cost estimate).

2. Other Costing Changes

As discussed in section III of today's document, EPA is using over 82 new sets of additional data (7 new sets from EPA's sampling program and 75 new sets from industry submitted data) to revise the target effluent concentrations used for the MP&M Cost & Loadings Model. Facilities use target effluent concentrations (or Long Term Averages (LTAs)) for designing a wastewater treatment system. The revised LTAs used in the Cost & Loadings Model for today's document and the methodology to develop those LTAs can be found in a memorandum entitled, “Cost Model LTA: Cost Model Procedure for Calculation Long Term Averages (LTAs)

for the MP&M Cost Model,” section 16.5.1, DCN 16742.

In addition, EPA has reviewed the equations used for various pollution prevention cost modules (i.e., paint water curtain, counter-current cascade rinsing, machine coolant recycling) and has made several minor corrections. For example, EPA corrected an error in the equation to calculate labor and electrical costs in the machine coolant recycling cost module.

EPA is also reviewing data received in comments to enhance the pollution prevention cost modules to incorporate reductions associated with the practices of the Pollution Prevention Alternative for metal finishing job shops discussed in the preamble to the proposed rule (66 FR 512). EPA has also prepared a report summarizing the findings of several case studies and information from additional research on pollution prevention in the metal finishing industry. If EPA incorporates the Pollution Prevention Alternative into the final rule, EPA will use the data in this report and the data submitted by commenters to develop more comprehensive pollution prevention cost modules. See section 16.4 of the public record, DCN 16865 for the report entitled, “Evaluation of the MP&M P2 Alternatives.”

3. Consideration of Additional Treatment to Existing Source BAT (Sand Filter)

EPA is considering the addition of a sand filter to follow the clarifier as BAT treatment technology for metal-bearing subcategories. EPA received many comments that the proposed limits were not consistently achievable by the proposed BAT technology. EPA has addressed this issue in several ways, including the collection of additional data and changes to the statistical methodology used for calculating numerical limits (
see
section VI of today's document for a discussion of revisions to the statistical methodologies). Commenters also suggested the use of a sand filter to further ensure that minor disruptions (or “burps”) in the treatment system would not result in violation of the limits.

When sampling BAT treatment systems in the MP&M Phase I and Phase II sampling programs, EPA collected data for treatment efficiency of sand filters. EPA found that the concentrations of pollutants of concern exiting the clarifier and entering the sand filter were often below treatable levels or below detection. EPA concluded that this occurred due to the fact that the clarifiers at these facilities were performing exceedingly well. EPA has found that when there are treatable levels of pollutants in the sand filter influent, the sand filter has good treatment efficiency. Therefore, although the addition of a sand filter is not likely to have much effect, if any, on the achievable long-term average effluent concentrations, with the possible exception of total suspended solids, it would ensure consistent effluent quality. If EPA does add a sand filter for the final rule, EPA will also calculate the loadings reduced for both direct and indirect facilities.

EPA notes that such an addition would also increase the compliance cost for the rule. To add a sand filter to the existing treatment train, EPA has developed a cost module for sand filtration. See the Multimedia Filtration Cost Module (DCN 15823) in the public record for detailed information on the sand filtration cost module. EPA has estimated national costs for the proposed Option 2 technology plus the addition of a sand filter for each of the metal-bearing subcategories. In general the cost of the “Option 2 + Sand Filter” represents a 32% increase over the revised Option 2 cost presented in section VII.A of today's document (
see
a document entitled, “Summary of Sand Filter Option Costs,” in section 6.7.1 of the public record, DCN 15823). EPA solicits comment on the addition of a sand filter to the BAT proposed technology option for metal-bearing subcategories in order to consistently meet the MP&M limits and standards, and on the cost module and national cost estimates.

G. New Survey Weights

EPA has revised the survey weights used to generate national estimates for some Phase I sites used in the Cost & Loadings Model and is considering using these for the final rule. The proposal weights contributed 14,769 Phase 1 facilities to EPA's estimate of the total number of MP&M facilities; in contrast, the revised weights contribute 11,865 to the total. The revised sample weights adjust for additional zero dischargers, remove the overestimate bias for non-zero dischargers, and exclude ineligible facilities. Additional information is provided in DCN 36086, section 19.5 of the public record. The revisions to the Phase I estimates are partly based upon imputed flows. For the final rule, if the imputed flows are substantially different as a result of using the revised imputation strategy described in section III.D, EPA also may decide to revise the sample weights for the Phase I facilities.

IV. Changes Considered to Applicability, Definitions, and Regulated Pollutants

A. Changes Considered to Applicability and Definitions

EPA received comment on several aspects of the applicability of the proposed rule. This section discusses changes EPA is considering for the final rule including: (1) The definition of “oily operations” for the Oily Wastes Subcategory; (2) clarification of differences between the General Metals and Oily Wastes subcategories; (3) clarification of applicability language as it pertains to printed wiring board job shops and printed wiring assembly facilities; and (4) clarification to the definition of new sources and the “grandfather” clause for facilities currently regulated as new sources under 40 CFR part 433 or 420.

As discussed in section III.A.1 of today's document, EPA is considering revising the applicability of the Oily Wastes Subcategory based on changes to the proposed definition for “oily operations.” EPA notes that such a revision would also affect the applicability of the General Metals Subcategory. EPA received comments concerning the definition of “oily operations” used in the applicability statement of the Oily Wastes Subcategory. Commenters provided data on several MP&M unit operations which were not part of the “oily operations” definition in the proposed rule. The data demonstrate low levels of metals in these unit operations that would not require treatment for metals removal. Based on the data received and a review of other unit operations containing only low concentrations of metals, EPA is currently considering a revision of the definition to read as follows:

Oily operations means one or more of the following: alkaline cleaning for oil removal, aqueous or solvent degreasing, corrosion preventative coating (as specified in § 438.61(b)); floor cleaning; grinding; heat treating; deformation by impact or pressure; machining; painting (spray or brush); steam cleaning; and testing (such as hydrostatic, dye penetrant, ultrasonic, magnetic flux); iron phosphate conversion coating; abrasive blasting, alkaline treatment without cyanide; assembly/disassembly; tumbling/barrel finishing/mass finishing/vibratory finishing; burnishing; electrical discharge machining; polishing, thermal cutting; washing of final products; welding; wet air pollution control for organic constituents; bilge water; adhesive bonding; and calibration.

EPA notes that iron phosphate conversion coating should be distinguished from zinc, manganese, or nickel phoshate conversion coating based on the constituents of the bath.

Manganese, nickel, or zinc phosphate conversion coating baths contain metals in addition to what may be added from the substrate. EPA solicits comment on the following definition: “Iron phosphate conversion coating baths consist of a phosphoric acid solution containing no metals. Any metal concentrations in the bath are from the substrate.”

EPA notes that in addition to adding several low metal concentration unit operations to the definition under consideration, the Agency is also considering the removal of “laundering” from the definition. EPA does not consider wastewater discharges from laundering (uniforms, etc.) at MP&M facilities to be process wastewater under the MP&M rule. The inclusion of laundering in the proposed definition of oily operations was an oversight which the Agency intends to correct for the final rule.

EPA did not include sampling data from paint stripping and electrolytic cleaning due to the elevated levels of metal constituents from these sources. For this notice, EPA did not include these unit operations in the definition of oily operations. However, EPA solicits comment on whether paint stripping for non-lead based paints should be included in the definition of oily operations. EPA solicits comment on the definition of iron phosphate conversion coating as an oily wastes operation to distinguish it from other phosphate conversion coating operations such as zinc or manganese phosphatizing. EPA also solicits comment on the need for a definition of “wet air pollution control for organic constituents” to distinguish it from “wet air pollution control for metals or fumes or dust.”

EPA is also clarifying the determination for placing a facility in the Oily Wastes or General Metals Subcategory. EPA notes that the determination for the Oily Wastes Subcategory depends on whether the facility discharges wastewater from only those operations considered as “oily operations,” as defined above. With the exception of mixed-use facilities, as proposed, a MP&M facility would fall under only one subcategory. If a facility is discharging wastewater from only “oily operations,” as defined above, then it would be in the Oily Wastes Subcategory. If a facility is discharging wastewater from oily operations and other MP&M operations, it would not be covered in the Oily Wastes Subcategory. If this facility is not a printed wiring board facility, metal finishing job shop, non-chromium anodizer, or steel forming & finishing facility, then it would be regulated under the General Metals Subcategory. If a facility was discharging wastewater from oily operations and performed, but did not discharge wastewater from, other MP&M operations, it would still be considered in the Oily Wastes Subcategory.

EPA received comment requesting clarification of whether or not wastewaters from MP&M-like operations, such as gravure cylinder and metallic platemaking, conducted within or for printing and publishing facilities were covered by the MP&M regulation. EPA excluded such facilities from the Electroplating (40 CFR 413.01(c)) and Metal Finishing (40 CFR 433.10(c)(1)) effluent guidelines. However, in the proposed MP&M rule, EPA did not discuss the applicability to these facilities. EPA did not include these facilities in the data collection efforts for the proposed regulation, and therefore, EPA's current intent is that the final rule would not apply to these facilities.

As discussed in section III.A of today's document, EPA has made some revision to the subcategorization of certain facilities. As discussed, EPA received comments that indicated that PWB job shops are more similar to PWB facilities than metal finishing shops and are therefore not properly categorized with the Metal Finishing Job Shops Subcategory. EPA also reviewed the operations of Printed Wiring Assembly facilities to determine whether it properly categorized these for proposal. As a result, EPA is considering a number of changes for the final rule in the categorization of such facilities. EPA's rationale for these changes is discussed in further detail in section III.A. EPA would place printed wiring board job shops in the Printed Wiring Board Subcategory instead of the Metal Finishing Job Shops Subcategory and would place printed wiring assembly facilities in the General Metals Subcategory.

EPA solicits comment on these intended revisions and whether or not EPA should include a definition to identify printed wiring assembly facilities in the General Metals Subcategory applicability statement. Commenters have suggested the following definition for Printed Wiring Assembly or Electronic Manufacturing Services facilities in the General Metals Subcategory:

Contract electronics design and assembly, also known as electronics manufacturing service (EMS) facilities provide some or all of the following services: electronics design, electronics assembly, electronics testing, and product assembly for other company's electronics products. Electronics assembly is the practice of building up the electronic product by inserting electronic components onto/into a bare circuit board, soldering the components to the board, and in some cases applying a conformal coating and/or cleaning the completed assembly. Other manufacturing functions include testing, “burn-in” of the components, and box build. Bare boards are, along with electronics components, an input to the assembly process. The manufacture of bare circuit boards is not part of the assembly or EMS process.

As described in the proposed MP&M rule (66 FR 506), both indirect and direct dischargers would be “new source” under the new rule if construction commences following 60 days after publication of the final rule. EPA recognizes that, for indirect dischargers, this may be different from what was done in past effluent guidelines, where the proposal date was used to determine a new source.

In addition, EPA received comments regarding the confusion of the “grandfather” clause for facilities that are currently subject to new sources limitations and pretreatment standards under either 40 CFR part 433 or 40 CFR part 420. EPA included language in the proposal to provide a protection period for facilities currently subject to “new source” regulation. This language may be found in the codified portion of the proposal under the NSPS and PSNS (new source) sections for the General Metals, Metal Finishing Job Shop, Non-Chromium Anodizing, Printed Wiring Board, and Steel Forming & Finishing subcategories. EPA's intent was to include language to protect facilities that are currently regulated as new sources under other regulations from a requirement to comply with the Metal Products and Machinery limitations and standards for a period not greater than 10 years from the date of completion of the new source construction. Section 306(d) of the CWA provides that any point source which is constructed to meet new source performance standards shall not be subject to any more stringent standards of performance during a 10-year period beginning on the date of completion of such construction or another statutorily defined period whichever ends first. 33 U.S.C. 1316(d).

At the suggestion of some commenters, EPA is considering moving the grandfathering language it had proposed to the existing source provisions (BPT, BAT, PSES) of each relevant subcategory for the final rule. For example in the General Metals Subcategory proposed §§ 438.12 (BPT) and 438.14 (BAT) this change could appear as follows:

(d) If a point source meets the applicability criteria in § 438.10, and construction was

commenced on that point source after [insert date 10 years prior to the date that is 60 days after the publication date of the final rule] but before [insert date that is 60 days after the publication date of the final rule], and it was subject to the provisions of 40 CFR 433.16, then the point source must continue to achieve the applicable standards specified in 40 CFR 433.16 until the expiration of the applicable time period specified in 40 CFR 122.29(d)(1). Thereafter, the source must achieve the applicable standards specified in this section.

Section 438.15 would be amended to add paragraph (e) as follows:

(e) If a source meets the applicability criteria in section 438.10, and construction was commenced on that source after [insert date 10 years prior to the date that is 60 days after the publication date of the final rule] but before [insert date that is 60 days after the publication date of the final rule], and it was subject to the provisions of 40 CFR 433.17, then the source must continue to achieve the applicable standards specified in 40 CFR 433.17 for ten years beginning on the date the source commenced discharge, or for the period of depreciation or amortization of the facility for the purposes of section 167 or 169 (or both) of the Internal Revenue Code, whichever is shorter. Thereafter, the source must achieve the applicable standards specified in this section.

Sections 438.16 (NSPS) and 438.17 (PSNS) would be amended by removing paragraph (a) and renumbering the remaining paragraphs. If EPA were to make this change for the final rule, it would make the appropriate changes for all effected subcategories. Finally, EPA has received comment regarding the transfer of certain operations from the existing Iron & Steel effluent guidelines (40 CFR part 420) to the proposed MP&M effluent guidelines. In the proposed MP&M rule, EPA refers to facilities with these operations as the Steel Forming & Finishing Subcategory. Specifically, EPA proposed to move the following operations from Iron & Steel to MP&M: surface finishing or cold forming of steel bar, rod, wire, pipe or tube; batch electroplating on steel; continuous electroplating or hot dip coating of long steel products (
e.g.
wire, rod, bar); batch hot dip coating of steel; and steel wire drawing. These operations produce finished products such as bars, wire, pipe and tubes, nails, chain link fencing, and steel rope. The Agency proposed to move these operations into the MP&M rule from stand-alone facilities, as well as from facilities that also have other operations that are currently regulated by the Iron & Steel effluent guidelines (i.e., facilities that are making steel and producing wire and wire products and are subject to both ELGs and the combined wastestream formula).

Since proposal, EPA revisited the record of the representative iron and steel finishing operations and compared the associated wastewater characteristics to those from the wire drawing facilities that were sampled under the MP&M rulemaking effort. EPA confirmed that the wastewater characteristics of the proposed transferred operations more closely resemble those from MP&M operations than those from representative iron and steel finishing operations. For instance, the average lead and zinc concentrations in wastewaters from the transferred wire drawing facilities are one to three orders of magnitude higher than those from representative iron and steel facilities. On the other hand, the concentrations for these pollutants are within the range of pollutant concentrations found in similar MP&M operations. Furthermore, most of the unit operations present in facilities being considered for transfer are the same as those found in the MP&M facilities, while only approximately 30% of these operations are the same as those found in the iron and steel facilities. EPA performed a comparison of flow rates between the transferred facilities and the proposed iron and steel finishing subcategory. The average flow rate from the proposed Iron & Steel Finishing subcategory is approximately half billion gallons per year, while the average flow rate from the transferred facilities is less than 30 million gallons per year (
see
Iron & Steel ELG record, Docket Number W-00-25, section 14.2, DCN #IS10740). EPA also notes that the average flow rate from the General Metals Subcategory of the MP&M rule is of the same order of magnitude as that from the transferred facilities. As a result of the above evaluations, EPA continues to conclude that the transferred operations would be more appropriately regulated under part 438, the MP&M effluent limitations guidelines and standards, in the Steel Forming & Finishing Subcategory. If EPA finalizes limitations and standards for the Steel Forming and Finishing subcategory of the MP&M regulation, EPA will also amend the applicability section of the iron and steel rulemaking to reflect this change. Until then, these operations continue to be regulated under part 420.

EPA also proposed moving certain electroplating operations currently subject to the Metal Finishing part 433 effluent limitations guidelines and standards into the revised part 420. Commenters on the Iron & Steel proposed rule strongly opposed the incorporation of the continuous electroplating of flat steel products (
e.g.,
sheet, strip, plate) into part 420, indicating the preference for electroplating operations of all types to be considered as a whole (
e.g.,
under the part 433 regulations or eventually the MP&M regulations). EPA proposed to regulate similar operations in the MP&M proposal in a number of subcategories. EPA decided not to include wastewater discharges from continuous electroplating of flat steel products in the final Iron & Steel regulations (signed on April 30, 2002). Wastewater discharges from these operations are currently subject to part 433 and EPA's present intention would be to include these in the Steel Forming & Finishing Subcategory of the final MP&M regulations. EPA will include these facilities in its analyses for the final rule. All non-confidential items pertaining to these facilities can be found in the public record for this document.

B. Changes Considered to the Pollutants Selected for Regulation

EPA received comments on several of the pollutants that were selected for regulation in the proposed rule. Based on new data from industry sources and EPA's data collection effort, EPA is considering whether to revise the list of pollutants selected for regulation. For example, EPA has also collected analytical data specific to the Steel Forming & Finishing Subcategory after proposal and is including this data in its analyses and in the MP&M rulemaking record.

1. Tin

EPA received comments regarding EPA's selection of tin as a regulated pollutant for metal-bearing subcategories. Many of the comments revolved around whether or not tin can be precipitated using EPA's proposed BAT technology that includes hydroxide precipitation. Of the 25 sites having tin data, 20 show tin removals greater than or equal to 95 percent. EPA's sampling data show a median removal of tin in BAT treatment systems of 98.6 percent. Analysis of the treatment systems employed by these sites shows that all but two use chemical precipitation followed by solids removal with either a clarifier or membrane filter. The two sites not using chemical precipitation list ultrafiltration, presumably for removal of oil and suspended solids, as their treatment technology.

Unlike other priority pollutant metals, tin does not readily form insoluble metal hydroxides in the chemical precipitation process. Based on information provided in the CRC

Handbook of Chemistry and Physics (68th Edition), there are two possible insoluble forms of tin that are produced during treatment of MP&M wastewater: tin sulfide (SnS) and tin phosphate (Sn
3
(PO
4
)
2
). The CRC lists the solubility of tin sulfide at 0.02 mg/L. The CRC lists tin phosphate as insoluble, but provides no maximum concentration. According to another reference (Freeman, H.M., “Standard Handbook of Hazardous Waste Treatment and Disposal, 1989), tin in metal-bearing wastewater is often found complexed with other constituents such as chelating agents present in electroless plating wastewater or cleaning solutions. Removal of the tin complex requires pH adjustment to break the tin-chelant bond followed by the reduction of tin to its elemental form.

Based on the information provided in the literature and gathered from the MP&M sampling episodes, no conclusions can be drawn regarding the excellent tin removals by the chemical precipitation systems sampled by EPA. The mechanism of tin removal is likely dependant on the chemistry of the influent wastewater, and involves a combination of sulfide precipitation, phosphate precipitation, and co-precipitation with other metals such as iron. EPA currently intends to retain tin as a regulated pollutant. EPA will reevaluate this intention if additional data received in comment indicates chemical precipitation followed by gravity settling will not meet the proposed effluent limit.

2. Total Sulfide

EPA also received many comments on its proposal to regulate total sulfide for many of the proposed subcategories. Commenters in the metal-bearing subcategories (i.e., general metals, metal finishing job shops, printed wiring boards, steel forming & finishing, and non-chromium anodizing) were concerned that regulation of sulfide would limit their ability to use sulfide-based chemistries in their treatment systems. Commenters pointed to other chemicals that EPA chose to not regulate based on their use as treatment chemicals (
e.g.,
aluminum, iron, calcium, magnesium, sodium, sulfate, chloride, ziram). Based on its use as a treatment chemical in the metal-bearing subcategories EPA intends to not regulate total sulfide for the metal-bearing subcategories in the final rule. EPA solicits comment on this change.

3. Molybdenum

EPA received comments regarding the selection of molybdenum as a regulated pollutant. Similar to the comments on tin, the comments revolved around whether or not molybdenum can be precipitated using hydroxide precipitation as is used in EPA's proposed BAT technology. EPA has reviewed literature to find out whether or not molybdenum will precipitate using either hydroxide or sulfide precipitation. and has found that molybdenum does not form metal hydroxide precipitates (
see
memorandum titled “Molybdenum,” section 16.2, DCN 17754). Molybdenum was observed at detectable concentrations in 283 of 1306 treatment system samples representing all 111 sampling episodes. The molybdenum raw waste concentrations ranged from 0.0007 to 40.3 mg/l. Effluent concentrations ranged from 0.0007 to 3.22 mg/L. Treatment effectiveness calculations of the chemical precipitation systems ranged from a negative 249% to a positive 71% removals (
see
memorandum titled “Molybdenum,” section 16.2, DCN 17754).

The sampled hydroxide precipitation treatment systems did not show a consistent ability to remove molybdenum from waste water. Molybdenum is, however, present is waste waters as described above and is removed incidentally in waste treatment systems. These removals may occur when molybdenum adheres to oily wastewaters that are removed in the oil water separation step or other treatment steps such as flocculation. EPA is reviewing these removal mechanisms for molybdenum. In addition to EPA's sampling data, airline industry submitted data demonstrates removals of molybdenum from BAT treatment systems with supplementary chemical additives between a negative 4% to a positive 85%. Therefore, EPA has included molybdenum removals in its estimates of pollutant reduction for the MP&M NODA. However, based on its inability to be treated by EPA's proposed hydroxide chemical precipitation technology, EPA is considering not regulating molybdenum in the final rule. EPA solicits comment on this change.

4. Steel Forming & Finishing Subcategory

As discussed in section II of today's document, EPA did not sample any BAT Steel Forming & Finishing facilities prior to proposal and solicited data from such facilities. Based on post-proposal sampling data collected for the Steel Forming & Finishing (SFF) Subcategory, EPA is considering the following pollutants for regulation of direct dischargers for this subcategory: chromium, copper, lead, nickel, zinc, manganese, molybdenum, tin, oil and grease (as HEM), and total suspended solids. EPA is considering the same pollutants as above for indirect dischargers except for oil and grease (as HEM) and total suspended solids. At proposal, EPA based the selection of pollutants for regulation for this subcategory on data transfers from the General Metals Subcategory. Of the pollutants proposed for regulation for the Steel Forming & Finishing Subcategory, EPA is considering to no longer regulate cadmium, cyanide, silver, total sulfide, organics (
e.g.,
TOP, TOC) as these pollutants are not found in SFF wastewater at treatable levels.

V. New Information and Consideration of Revision to Economic & Benefit Methodologies

A. Revised Cost Pass-Through and Market Structure Analysis

As discussed in Chapter 5 of the document titled, “Economic, Environmental, and Benefits Analysis for the Proposed Metal Products & Machinery Rule,” (EEBA) (EPA-821-B-00-008), and in response to comments received on the proposal economic impact analysis, EPA revised the analysis of cost pass-through potential for the 19 MP&M sectors. This analysis estimates how much of compliance-related cost increases a sector can be expected to pass on to its customers in higher prices. The analysis consists of two parts:

• An econometric analysis of the historical relationship of output prices to changes in input costs, and

• An analysis of market structure characteristics.

These two analyses together provide a cost pass-through coefficient for each sector. This analysis refines the methodology developed for the Phase 1 and proposal MP&M analyses in several places, and updates the data used through 1996, the base year of the regulatory analyses. Changes to reporting by NAICS codes for the Census economic data but not for price indices in 1997 prevented use of later years' data in this analysis. Today's document provides a summary of the revised analysis. More complete documentation is provided in section 17.2.1, DCN 35250, of the public record.

1. Econometric Analysis

EPA performed an econometric analysis of input costs and output prices to estimate cost pass-through elasticities for 18 of the 19 Phase I

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Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3A02-13808. Public record. Not legal advice.