[Federal Register Volume 64, Number 103 (Friday, May 28, 1999)]
[Proposed Rules]
[Pages 28949-28963]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-13659]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 268

[FRL-6351-4]
RIN-2050-AE54


Potential Revisions to the Land Disposal Restrictions Mercury 
Treatment Standards

AGENCY: Environmental Protection Agency.

ACTION: Advance notice of proposed rulemaking (ANPRM).

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SUMMARY: The Environmental Protection Agency (EPA or Agency) is 
considering publication of a proposed rule to revise the 40 CFR part 
268 Land Disposal Restrictions (LDR) treatment standards applicable to 
mercury-bearing wastes. This ANPRM is intended to give advance notice 
of EPA's comprehensive reevaluation of the treatment standards for 
mercury-bearing hazardous wastes as well as various options, issues, 
and data needs related to potential mercury treatment standard 
revisions. The Agency requests additional data and comments on these 
issues and options.

DATES: Written and electronic comments in response to this ANPRM must 
be received on or before July 27, 1999.

ADDRESSES: Commenters should submit an original and two copies of their 
comments referencing Docket No. F-1999-MTSP-FFFFF to: the RCRA 
Information Center (RIC), U.S. Environmental Protection Agency 
Headquarters (5305W), 401 M Street, SW, Washington, D.C. 20460. Courier 
deliveries of comments should be submitted to the RIC at the address 
listed below. Comments may also be submitted electronically through the 
Internet to:
    RCRA[email protected]. Comments in electronic format should 
also be identified by the docket number F-1999-MTSP-FFFFF. Submit 
electronic comments as an ASCII file and avoid the use of special 
characters and any form of encryption. If possible, EPA's Office of 
Solid Waste (OSW) would also like to receive an additional copy of the 
comments on disk in WordPerfect 6.1 file format.
    Commenters should not submit electronically any confidential 
business information (CBI). An original and two copies of the CBI must 
be submitted under separate cover to: Regina Magbie, RCRA CBI Document 
Control Officer, Office of Solid Waste (5305W), U.S. EPA, 401 M Street, 
S.W., Washington, D.C. 20460.
    The Agency will consider the public comments during development of 
any proposed rule related to this action. The Agency urges commenters 
submitting data in support of their views to include with the data 
evidence that appropriate quality assurance/quality control 
1 (QA/QC) procedures were followed in generating the data. 
Data that the Agency cannot verify through QA/QC documentation may be 
given less consideration or disregarded in developing regulatory 
options for proposal and final rules.
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    \1\ For guidance, see Final Best Demonstrated Available 
Technology (BDAT) Background Document for Quality Assurance/Quality 
Control Procedures and Methodology; USEPA, October 23, 1991.
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    Public comments and supporting materials are available for viewing 
in the RIC, located at Crystal Gateway One, 1235 Jefferson Davis 
Highway, First Floor, Arlington, Virginia. The RIC is open from 9 a.m. 
to 4 p.m., Monday through Friday, except for Federal holidays. To 
review docket materials, the public must make an appointment by calling 
703-603-9230. The public may copy a maximum of 100 pages from any 
regulatory docket at no charge. Additional copies cost $0.15 per page. 
The docket index and notice are available electronically. See the 
Supplementary Information section for information on accessing it.

FOR FURTHER INFORMATION CONTACT: For general information, contact the 
RCRA Hotline at 800-424-9346 or TDD 800-553-7672 (hearing impaired). In 
the Washington, D.C., metropolitan area, call 703-412-9810 or TDD 703-
412-3323.
    For information on specific aspects of this document, contact Rita 
Chow, Office of Solid Waste (5302W), U.S. Environmental Protection 
Agency, 401 M Street, S.W., Washington, D.C. 20460, 703-308-6158, e-
mail address: [email protected].

SUPPLEMENTARY INFORMATION: The docket index and the notice are 
available on the Internet. From the World Wide Web (WWW), type http://
www.epa.gov/fedrgstr. For the text of the notice, choose: Year/Month/
Day. The document may also be obtained using File Transfer Protocol 
(FTP) at: ftp:epa.gov.

Login: anonymous
Password: your Internet address

Glossary of Acronyms

APCD--Air Pollution Control Device
ATON--Aid-to-Navigation
ATTIC--Alternative Technology Treatment Information Center
BDAT--Best Demonstrated Available Technology
BIF--Boiler and Industrial Furnace
BRS--Biennial Reporting System
DOE--Department of Energy
IMERC--Incineration of Wastes Containing Organics and Mercury 
(Specified Treatment Method)
LDR--Land Disposal Restrictions
MACT--Maximum Achievable Control Technology
NESHAP--National Emissions Standard for Hazardous Air Pollutants
NHWCS--National Hazardous waste Constituent Survey
PBT--Persistent, Bioaccumulative, and Toxic
PCB--Polychlorinated Biphenyls
POTW--Publically Owned Treatment Works
PSD--Prevention of Significant Deterioration Permit
RCRA--Resource Conservation and Recovery Act
RMERC--Roasting or Retorting of Mercury-Bearing Hazardous Wastes 
(Specified Treatment Method)
RREL--Risk Reduction Engineering Laboratory
S/S--Solidification/stabilization
SPC--Sulfur Polymer Cement
TCLP--Toxicity Characteristic Leaching Procedure
TOC--Total Organic Carbon
TRI--Toxic Release Inventory
VISITT--Vendor Information System for Innovative Treatment Technology
WMNP--Waste Minimization National Plan

Table of Contents

I. Introduction
    A. Agency's Concern for Mercury
    B. Key Issues Addressed in the ANPRM
II. Background
    A. Mercury in the Environment
    B. The Resource Conservation Recovery Act
    C. Mercury Treatment Standards
III. Mercury Hazardous Waste Generation and Management
    A. Industries Generating Mercury-Bearing Wastes
    B. Generation of Mercury-Bearing Hazardous Wastes
IV. Current RCRA Regulations Governing Treatment of Mercury-Bearing 
Hazardous Wastes
    A. RCRA Waste Code Classification and Treatment

[[Page 28950]]

    B. Existing LDR Regulations for Mercury-Bearing Wastes
V. Mercury Treatment Technologies-Roasting and Retorting of Mercury 
Wastes
    A. Process and Regulation
    B. Air Emissions from Roasting and Retorting
    C. Request for Comment
VI. Mercury Treatment Technologies-Incineration of Mercury Wastes
    A. Current Regulations
    B. Characteristics of Mercury in Incinerators and Current 
Emission Control Systems
    C. Amount of Mercury Emitted from Incinerators and Other 
Hazardous Waste Combustors
    D. General Waste Characterization Data on Mercury in Hazardous 
Waste Streams
    E. EPA's Re-Evaluation of the IMERC Standard
    F. Additional Considerations Related to Alternatives to 
Incineration
    G. Request for Comment
VII. Regulatory Options Involving Source Reduction
VIII. Mixed Wastes
IX. Discussion of Alternative Treatment Technologies
    A. Possible Alternative Technologies to Retorting
    B. Possible Alternative Technologies to Incineration
    C. Current Mercury Treatment Companies
    D. Request for Comment
X. Possible Revisions to the Mercury LDRs
    A. Purpose of ANPRM
    B. Schedule
    C. Impact on Small Businesses
    D. Impact on State Programs
    XI. Administrative Requirements
    A. Regulatory Flexibility Act
    B. Executive Order 13045

I. Introduction

    With this document, the Agency marks the beginning of a 
comprehensive review of existing RCRA waste treatment regulations 
applicable to mercury-bearing wastes and of our effort to revise, if 
necessary and appropriate, these regulations to improve treatment and 
land disposal methods. We decided to publish an ANPRM at this time 
because we expect to benefit significantly from early public input on 
mercury waste generation and treatment, including information on 
alternative treatment technologies and on source reduction 
opportunities. The nature and extent of amendments to the mercury 
treatment standards have not yet been determined. Any potential 
revisions will ultimately be based on the comments we receive on this 
ANPRM, as well as data obtained from other sources (e.g., ongoing 
treatability studies). As warranted, a proposal to amend the current 
regulations will appear in a future Federal Register document.

A. Agency's Concern for Mercury

    As evidenced by EPA's Mercury Study Report to Congress 
2, mercury is an element that the Agency has studied quite 
extensively in recent years. Moreover, a recent Agency Federal Register 
notice identified mercury as one of the ``53 persistent, 
bioaccumulative, and toxic (PBT) chemicals and chemical categories 
which may be found in hazardous wastes regulated under RCRA'' (63 FR 
60332, November 9, 1998). In addition, the EPA Action Plan for Mercury 
3 lists this ANPRM as one of the twelve ``most significant 
actions that EPA is undertaking to deal with the problem of mercury 
exposure.''
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    \2\  ``Mercury Study Report to Congress,'' Volumes I-VIII, EPA-
452/R-97-003, December 1997.
    \3\  EPA Action Plan for Mercury (Attachment 1 to ``An Agency-
wide Multi-media Strategy for Priority PBT Pollutants'') can be 
found at www.epa.gov/opptintr/pbt/pbtstrat.htm.
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    This ANPRM deals with a small aspect of the overall mercury 
problem, this being the treatment and disposal of mercury-bearing 
hazardous wastes. Nevertheless, the potential problems that exist in 
this area are significant, as mercury can both leach out of hazardous 
wastes and also be emitted from the various treatment processes.

B. Key Issues Addressed in the ANPRM

    This ANPRM focuses on several key issues with the current LDR 
mercury treatment standards:
    Incineration--We are interested in pursuing further the issue of 
mercury air emissions from incineration units. One of the original 
premises behind the current mercury treatment regulations was that 
incineration would be a pretreatment step to mercury recovery, but this 
premise should be re-examined at this point, given new information 
about incineration of mercury wastes as well as the upcoming Hazardous 
Waste Combustion rule. Also, we currently allow high mercury, low 
organic wastes to be incinerated, but alternative treatment 
technologies may be preferable for these wastes. We want to investigate 
the impacts of reducing the number of waste types allowed or required 
to be incinerated (e.g., potentially only allow high organic, low 
mercury wastes, or organomercury wastes).
    Retorting--From comments on this ANPRM, we hope to get a better 
idea of the full environmental impact of our waste treatment standards. 
Our treatment standards requiring recovery of mercury via retorting are 
a case in point. For example, air emissions and the disposal of the 
residues from secondary production (i.e., recycling-oriented processes) 
ought to be weighed against the diminishing benefits of recovery when 
such secondary production exceeds demand for the recycled product. In 
some cases, direct treatment for disposal could have some environmental 
advantages in certain supply-demand situations that have not previously 
been fully appreciated. We also want to investigate whether retorting 
(i.e., thermal recovery) is currently required for wastes that are 
either not amenable to or are inappropriate for (e.g., mixed wastes) 
this treatment. Finally, although several factors suggest that 
retorting emissions are not significant, we still want to determine if 
there are data that support this suggestion.
    Source Reduction Options--EPA developed the current treatment 
regulations under statutory deadlines that impeded the exploration of 
potential source reduction technologies that could reduce or eliminate 
the generation of mercury-bearing wastes from many sources. The ANPRM 
contains a discussion of this investigation and potential options that 
might provide additional incentives for decreasing the amount of 
mercury in hazardous waste.

II. Background

A. Mercury in the Environment

    Control of the environmental risks posed by mercury is a complex 
problem for a number of reasons. First, mercury and its compounds are 
mobile in the environment. Elemental mercury is volatile under both 
ambient and combustion temperatures and is released into the 
environment mostly through air emissions from commercial and industrial 
sources. It can remain in the atmosphere for up to one year, and hence 
can be widely dispersed and transported thousands of miles from the 
source of the emissions. When in the form of mercury salts, mercury air 
emissions are deposited more locally.
    Second, multiple pathways exist for exposure. The risks associated 
with various exposure pathways depend strongly on the chemical form 
(i.e., species) of mercury involved. After deposition from the 
atmosphere, mercury can be methylated (especially in water bodies) to 
form the more toxic and bioaccumulative methylmercury. Exposure to 
levels of methylmercury found in fish taken from polluted water bodies 
has been associated with neurological and developmental defects in 
humans, with the developing fetus most at risk. To reduce the risks of 
exposure to methylmercury over time,

[[Page 28951]]

cost-effective strategies are needed both domestically and 
internationally to minimize the generation of mercury-bearing hazardous 
wastes.
    Some evidence suggests that, because mercury is a persistent, 
bioaccumulative, and toxic (PBT) substance, small releases may 
contribute to the build up of mercury in the environment, especially 
the aquatic environment, over time, which may increase the potential 
for environmental and human health impacts. Consequently, EPA is 
looking at whether we may need to change the LDR mercury treatment 
standards.

B. The Resource Conservation and Recovery Act

    One objective of the Resource Conservation and Recovery Act 
(RCRA)--the major hazardous waste statute--is to minimize the 
generation of hazardous waste and the land disposal of hazardous waste 
by encouraging process substitution, materials recovery, properly 
conducted recycling and reuse, and treatment (see RCRA section 1003). 
To further this objective, the Agency has set as goals of its Waste 
Minimization National Plan (WMNP) 4 to:
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    \4\ Waste Minimization National Plan, USEPA, 1994, EPA530-R-94-
045.
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     Reduce, as a nation, the presence of the most persistent, 
bioaccumulative, and toxic (PBT) chemicals in RCRA hazardous wastes 10 
percent by the year 2000, and at least 50 percent by the year 2005 
(from a 1991 baseline);
     Promote source reduction (and recycling where RCRA PBT 
chemicals cannot be reduced at the source) over treatment and disposal 
technologies; and
     Avoid the transfer of RCRA PBT chemicals across 
environmental media.
    Consistent with the goals of RCRA and the WMNP, the Agency seeks to 
reduce the generation of hazardous wastes containing mercury. When this 
is not feasible, the Agency wants to look carefully at other 
opportunities to improve the recycling and treatment of residual 
mercury-bearing waste to further reduce air emissions, the mobility of 
mercury species at the time of disposal, and the potential for future 
biological or chemical conversion to other mobile and bioaccumulative 
species of mercury.

C. Mercury Treatment Standards

    EPA established treatment standards for mercury-bearing wastes as 
part of two rulemakings. The LDR First Third final rule (53 FR 31166, 
August 17, 1988) established standards for RCRA hazardous waste code 
K071 (brine purification muds from the mercury cell process in chlorine 
production, where separately prepurified brine is not used), and the 
LDR Third Third final rule (55 FR 22569, June 1, 1990) established 
standards for five additional RCRA mercury-bearing waste codes: D009, 
characteristic mercury wastes; K106, wastewater treatment sludge from 
the mercury cell process in chlorine production; P065, mercury 
fulminate wastes; P092, phenyl mercuric acetate wastes; and U151, 
miscellaneous mercury wastes.
    For all of these wastes, EPA established two treatment 
subcategories: a high mercury subcategory, which includes wastes with a 
total mercury concentration greater than or equal to 260 mg/kg; and a 
low mercury subcategory, which includes wastes with a total mercury 
concentration less than 260 mg/kg.
     High mercury wastes are required to be roasted or retorted 
(``RMERC''), or incinerated (``IMERC'') if organics are present. RMERC 
residues must then meet a numerical treatment standard of 0.20 mg/L 
prior to land disposal, as measured by the toxicity characteristic 
leaching procedure (TCLP). IMERC residues must meet a numerical 
treatment standard of 0.025 mg/L TCLP.
     Low mercury wastes are not subject to a specific 
technology for treatment but must meet a numerical treatment standard 
of 0.025 mg/L TCLP.

III. Mercury Hazardous Waste Generation and Management

A. Industries Generating Mercury-Bearing Wastes

    Industrial use of mercury in the U.S. has been on the decline in 
recent years. Also, mercury is no longer produced from mercury ore in 
the United States, as the last mercury ore mine closed in 1990. 
However, mercury is still produced as a byproduct from the mining of 
gold ores and from secondary production. Nearly all of the mercury used 
in the United States is derived from secondary sources. Common 
secondary sources include spent batteries, chlor-alkali wastewater 
sludges, mercury vapor and fluorescent lamps, dental amalgams, 
electrical apparatus, and measuring instruments. The secondary 
producers typically use high-temperature roasting and retorting to 
recover mercury from the materials and distillation to purify 
contaminated liquid mercury metal.
    Data on estimated industrial demand for mercury show a general 
decline in domestic mercury use since demand peaked in 1964. Table 1 
describes the mercury production and consumption in the U.S. for 1990-
1997. In 1997, 346 metric tons of mercury were used in industrial 
processes, 389 metric tons were produced by secondary mercury producers 
(i.e., producers recovering mercury from waste products), 134 metric 
tons were exported, and 164 metric tons were imported. These figures 
continued the trend since 1995 of secondary production exceeding 
industrial consumption.5 Domestic demand fell by more than 
75% between 1988 (1503 metric tons) and 1997 (346 metric tons). Much of 
this decline can be attributed to the elimination of mercury as a paint 
additive and the reduction of mercury in batteries. Other reasons for 
the reduction include the military phase-out of mercury fulminate as a 
primer in military explosives and the decline in the number of chlor-
alkali facilities using the mercury cell method of chlorine production. 
Use of mercury by other source categories remained essentially the same 
between 1988 and 1996.6 The data suggest that industrial 
manufacturers who use mercury are shifting away from its use except 
where mercury is considered essential. However, mercury consumption in 
the categories of Electrical and Electronic Uses and Instruments and 
Related Products is still growing, and is expected to continue to grow 
due to the increase in the manufacture of computers and other 
electrical equipment.7
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    \5\ Robert G. Reese, Jr, US Geological Survey, Minerals 
Information, 1997.
    \6\ Mercury Study Report to Congress, USEPA, December 1997, 
Volume I: Executive Summary, page 3-8.
    \7\ The Status of Mercury in the United States, Draft 2, 
September 10, 1996, page A3-6.

[[Page 28952]]



                                                     Table 1.--Mercury Production and Use Statistics
                                                                      [Metric tons]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                  1990      1991      1992      1993      1994      1995      1996      1997      1998E
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mine Production:
    --Principal product \1\...................................       448  ........  ........  ........  ........  ........  ........  ........  ........
    --Byproduct from gold mines...............................       114        58        64         W         W         W         W         W         W
Secondary Production:
    --Industrial..............................................       108       165       176       350       446       534       446       389       400
    --Government \2\..........................................       193       215       103  ........  ........  ........  ........  ........  ........
Imports for Consumption.......................................        15        56        92        40       129       377       340       164       200
Exports.......................................................       311       786       977       389       316       179        45       134       150
Shipments from National Defense Stockpile \3\.................        52       103       267       543        86  ........  ........  ........  ........
Industry Stocks, year-end \4\.................................       197       313       436       384       469       321       446       203       200
Industrial Consumption (reported).............................       720       554       621       558       483       436       372       346       400
Price, average dollars per flask:
    D.F. Goldsmith............................................   $249.22   $122.42   $201.39   $186.51   $194.45   $247.40   $261.65        NA        NA
    Free market...............................................        NA        NA        NA        NA        NA        NA        NA   $159.52      $180
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source: Robert G. Reese, Jr, US Geological Survey, Minerals Information, 1997, 1999.
E--Estimated. W--withheld for confidentiality. NA--Not available
\1\ Comprises only mercury produced at McDermitt Mine, as reported in Placer Dome Inc. Annual and 10-K reports. The mine was closed in November 1990.
\2\ Secondary mercury shipped from U.S. Department of Energy stocks.
\3\ Shipments from the government stockpile were suspended in 1995.
\4\ Stocks at consumers and dealers only. Mine stocks withheld to avoid disclosing proprietary data.

    Table 2 presents estimates of mercury emissions from the EPA 
Mercury Study Report to Congress (USEPA, December 1997), and national 
emission estimates for hazardous waste combustors for 1990, 1994, and 
1997. The Report to Congress identifies combustion sources, including 
utility and commercial/industrial boilers, as the major source of 
mercury emissions. Hazardous waste combustion emissions and emissions 
from secondary mercury production are estimated to be less than five 
percent of overall mercury emissions. In 1990 and 1994, mercury 
emissions from hazardous waste combustion sources totaled approximately 
6.4 metric tons per year, and for 1997, these emissions decreased to 
approximately 6.0 metric tons per year.8 Table 2 shows a 
further breakdown of the mercury emissions contribution from each 
hazardous waste combustor category.
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    \8\ When interpreting any apparent data trends in Table 2, you 
should note that differences in emissions estimates are due to a 
combination of factors including actual data from performance in the 
field, revisions to our estimation methodology, and changes in the 
number of facilities operating within each category. See documents 
noted as sources for Table 2.

               Table 2.--Available Mercury Emissions Data
                              [Metric Tons]
------------------------------------------------------------------------
                                 1990(a)        1994(b)        1997(c)
------------------------------------------------------------------------
Area sources................  ............          3.1
Combustion sources..........  ............        125.2
Manufacturing sources.......  ............         14.4
Miscellaneous sources.......  ............          1.3
                             -------------------------------------------
    Total Air emissions.....         213          144
                             ===========================================
-HW Cement Kilns............           3.2          2.7             1.5
-HW Incinerators............           2.9          3.5             4.4
-HW Lightweight Aggregate              0.3          0.3             0.05
 Kilns......................
                             -------------------------------------------
    Total HW Combustors (d)            6.4          6.4             6.0
     (% of total emissions).                       (4.4)
                             ===========================================
Secondary Hg Production (e)            0.7          0.4
 (% of total emissions).....                       (0.3)
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a Source Category Listing for Section 112(d)(2) Rulemaking Pursuant to
  Section 112(c)(6) Requirements, USEPA, April 10, 1998; 63 FR 17338,
  Table 1.
b Mercury Study Report to Congress, USEPA, December 1997, Volume I:
  Executive Summary, page 3-6.
c Note to Laura McKelvey, USEPA, from Frank Behan, USEPA, dated July 1,
  1998. This emissions inventory supports the rulemaking to revise the
  technical standards for hazardous waste combustion facilities and will
  be included in a technical support document for that rule.
d Total HW Combustor emissions (6.4 metric tons) are a subcategory of
  the Combustion source emissions (125.2 metric tons) that appear in the
  Mercury Study Report to Congress (see note ``b'' above).
e Secondary Hg Production emissions (0.4 metric tons) are a subcategory
  of the Manufacturing source emissions (14.4 metric tons) that appear
  in the Mercury Study Report to Congress (see note ``b'' above).


[[Page 28953]]

B. Generation of Mercury-Bearing Hazardous Wastes

    The background document ``Analysis of Current Mercury Waste 
Generation and Treatment'' in the docket for today's notice includes 
tables that break down the generation of mercury-bearing hazardous 
wastes by waste code, waste form, and SIC Code based on the National 
Biennial RCRA Hazardous Waste Report (BRS) database.\9\ While the BRS 
provides a general idea of how much hazardous waste is generated, the 
numbers can be misinterpreted. For example, the BRS does not provide 
mercury concentrations in the waste streams. Therefore, we do not have 
a good estimate for the total amount of mercury that is treated by non-
combustion technologies in the United States.
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    \9\ BRS data can be found at www.epa.gov/epaoswer/hazwaste/data/
---------------------------------------------------------------------------

    Another interpretive issue with BRS data is that some waste 
quantities can be overestimates of the actual amount of waste produced. 
For example, some waste streams may be given multiple waste codes, one 
code being the specific waste code (e.g., K071), and another code being 
the general characteristic code (e.g., D009). This leads to an 
overestimate of the actual quantity generated.
    According to the 1995 BRS, approximately 12.2 million metric tons 
of mercury-bearing hazardous waste (wastewater and nonwastewater) were 
generated. This represents an increase from the 1993 BRS estimate of 
11.5 million metric tons. The National Hazardous Waste Constituent 
Survey (NHWCS), which was designed to correspond with 1993 BRS data, 
estimated that almost 19 million metric tons of mercury-bearing wastes 
were managed. This NHWCS was created by EPA's Office of Solid Waste in 
1996 and distributed to over 200 of the largest generators and managers 
of hazardous industrial process wastes in the U.S. These facilities 
account for over 90 percent of the total waste quantity in the 
hazardous waste universe as reported in the 1993 BRS.
    The NHWCS also included estimates of the total amount of mercury 
managed by treatment technologies. The three technologies that were 
listed, and their respective mercury quantities, were ``other 
treatment,'' 3257 metric tons; ``aqueous inorganic treatment,'' 33 
metric tons; and ``landfill,'' 30 metric tons. In the ``other 
treatment'' category, one facility (DOE/WRSC Savannah River) accounts 
for approximately 98 percent of the total constituent quantity. Without 
this facility, the constituent total for ``other treatment'' would be 
5.6 tons. Since the survey was voluntary and limited to the largest 
waste streams, it is likely that it did not include many retorters and 
incinerators of mercury (especially high subcategory mercury) wastes.
    Table 3 presents data from the Toxics Release Inventory (TRI) 
database. The TRI is an information source about toxic chemicals that 
are being used, manufactured, treated, transported, or released into 
the environment. A facility is required to submit a TRI report if it 
(1) has ten or more full-time employees, and (2) manufactures or 
processes over 25,000 pounds of the approximately 600 designated 
chemicals or 28 chemical categories specified in the regulations, or 
uses more than 10,000 pounds of any designated chemical or category, 
and (3) engages in certain manufacturing operations in the industry 
groups specified in the U.S. Government Standard Industrial 
Classification Codes (SIC) 20 through 39. Federal facilities also are 
required to report following an August 1995 Executive Order.
    EPA emphasizes that the BRS and NHWCS data presented above and the 
emissions data in Table 3 are estimates that may overestimate 
generation. The Agency welcomes any information that may help to 
construct a more accurate picture of the current mercury waste 
universe. This would include current data on waste generation (types, 
quantities, and mercury concentrations in the wastes), current waste 
management practices, problems and/or constraints on treating or 
recovering these wastes, as well as information on any waste 
minimization activities that may have been implemented to reduce or 
eliminate waste generation.

                                               Table 3.--TRI Data
                                                  [Metric Tons]
----------------------------------------------------------------------------------------------------------------
                                                              1993          1994          1995          1996
----------------------------------------------------------------------------------------------------------------
TRI total production-related waste:
    -Mercury............................................  ............       407.5         459.6         390.1
    -Mercury compounds..................................  ............        55.7          70.6          36.1
    -Mercury + Mercury compounds........................  ............       463.2         530.2         426.2
TRI wastes to recycling:
    -Mercury............................................  ............       390.0         443.7         375.4
    -Mercury compounds..................................  ............        42.6          56.8          21.9
    Mercury + Mercury compounds.........................  ............       432.6         500.5         397.3
TRI mercury + mercury compounds:
    Fugitive air emissions..............................         5.28          4.43          4.85          5.51
    Stack emissions.....................................         1.57          1.87          2.55          2.24
    Surface water discharges............................         0.20          0.15          0.15          0.25
    Underground injection...............................         0.007         0.003         0.003         0.004
    On-site land releases...............................         0.82           .061          .046          .024
    Off-site disposal...................................        15.7          17.6          94.4          11.7
    On-site treatment...................................        NA             5.02          2.86          1.87
    Transfers to energy recovery........................         0             0             0.23          0.23
    Transfers to treatment..............................         0.79          1.75          7.59          6.55
    Transfers to POTWs..................................         0.007         0.007         0.011         0.007
    Other off-site transfers............................         0             0             0.40          0
TRI total not recycled:
    -Mercury............................................        14.7          18.2          17.8          13.7
    -Mercury compounds..................................         9.7          13.2          95.7          15.0

[[Page 28954]]

 
    -Mercury + mercury compounds a......................        24.4          31.4         113.5          28.6
----------------------------------------------------------------------------------------------------------------
a totals may not add due to rounding

IV. Current RCRA Regulations Governing Treatment of Mercury-Bearing 
Hazardous Wastes

A. RCRA Waste Code Classification and Treatment

    EPA's hazardous waste classification system identifies six 
categories of mercury-bearing wastes, each of which has a separate RCRA 
waste code.
    The following is a detailed description of the six mercury waste 
codes:
    D009 Wastes--Characteristic Mercury Wastes. D009 wastes are 
extremely variable in composition, and depend on the industry and 
process that generate the waste. Some of the more common types of D009 
wastes include miscellaneous wastes from chlor-alkali production 
facilities (especially cell room trench sludge and activated carbon for 
liquid or gas purification), used fluorescent lamps, batteries, 
switches, and thermometers. D009 wastes are also generated in the 
production of organomercury compounds for fungicide/bactericide and 
pharmaceutical uses, and during organic chemicals manufacturing where 
mercuric chloride catalyst is used.10
---------------------------------------------------------------------------

    \10\ U.S. EPA, Best Demonstrated Available Technology (BDAT) 
Background Document for Mercury Wastes, Nov 1989, page 2-18.
---------------------------------------------------------------------------

    Mercury concentrations within D009 wastes may range from 0.20 mg/L 
TCLP to greater than 75 percent of the total waste composition. D009 
wastes may also contain organic compounds, usually when mixed with 
solvent wastes.
    Although characterization data for D009 wastes are limited, some 
conclusions can be made regarding potential treatment concerns. Wastes 
with greater than 500 ppm 40 CFR part 261, appendix VIII organics (such 
as benzene) may be problematic for commercial retorting facilities due 
to the permitting requirements for boiler and industrial furnaces (BIF) 
(40 CFR 266.100(c)). At least two facilities are unable to handle 
wastes with these levels of volatile organics due to the additional 
permitting that would be required. However, these two facilities are 
capable of treating non-volatile activated carbons.
    K071 Wastes--Brine purification muds from the mercury cell process 
in chlorine production, where separately prepurified brine is not used. 
K071 wastes are generated by the chlor-alkali industry in the mercury 
cell process. In this process, sodium chloride is dissolved to form a 
saturated brine solution. The brine solution is purified by 
precipitation, using hydroxides, carbonates, or sulfates. The 
precipitate is dewatered to form K071 wastes, while the purified brine 
continues in the process. The depleted solution from the mercury cell 
is ultimately recycled to the initial step of the process.
    Available analytical information for K071 brine purification muds 
show that these wastes consist primarily of inorganic solids and water. 
The normal total mercury content of K071 wastes is less than 100 parts 
per million (ppm) and is normally characterized as metallic mercury or 
soluble mercuric chloride.11 Mercury from K071 wastes is 
typically recovered using a wet process, reflecting the BDAT for this 
waste.
---------------------------------------------------------------------------

    \11\ U.S. EPA, BDAT Document for Mercury Wastes, November 1989, 
page 2-11.
---------------------------------------------------------------------------

    K106 Wastes--Wastewater treatment sludge from the mercury cell 
process in chlorine production. Like K071 wastes, K106 wastes are 
generated from chlorine production using the mercury cell process. 
Effluent from the mercury cell includes spent brine, a portion of which 
is recycled and a portion of which is purged to wastewater treatment. 
Other plant area wastewaters (e.g., stormwater, washdown waters) are 
also typically sent to this treatment system. The wastewater treatment 
process generates a sludge through precipitation and filtering, which 
is K106 waste. Sulfides (as either sodium sulfide, Na2S, and/or sodium 
bisulfide, NaHS) have been commonly used as a precipitation agent for 
at least the last 10 years (1988 to 1998), according to data from the 
Chlorine Institute. Sludges generated in this manner are comprised, in 
part, of mercuric sulfide. Other (minor) precipitation agents result in 
the formation of mercury hydroxide or in elemental mercury. However, 
sulfide precipitation is preferable to hydroxide precipitation using 
hydrazine because mercury hydroxide is susceptible to matrix 
dissolution over a wide range of pH under oxidizing conditions.
    Available analytical information for K106 wastes indicates they are 
primarily composed of water and diatomaceous earth filter aid. This is 
true for K106 wastes generated by both sulfide treatment and hydrazine 
treatment. K106 wastes from sulfide precipitation contain approximately 
4.4 percent mercury, as mercuric sulfide, while K106 wastes from 
hydrazine treatment contain approximately 0.5 percent mercury, as 
mercurous hydroxide.12
---------------------------------------------------------------------------

    \12\ U.S. EPA, BDAT Document for Mercury Wastes, November 1989, 
page 2-11.
---------------------------------------------------------------------------

    The mercury concentration in K106 waste is consistently greater 
than 260 mg/kg and therefore retorting is a required technology for 
this waste. K106 waste also contains significant levels of sulfides/
sulfates, sodium chloride, and organics, although the mercury is likely 
in an elemental or a sulfide form.
    P065 Wastes--Mercury fulminate. P065 wastes consist of discarded 
mercury fulminate product, off-specification mercury fulminate product, 
and container or spill residues thereof. No waste characterization data 
were available for P065 listed wastes. The quantity of P065 waste is 
expected to have declined, as the military has phased out its use in 
explosives.13
---------------------------------------------------------------------------

    \13\ Mercury Treatment and Storage Options Summary Report, A.T. 
Kearney report for USEPA Reg 5, May 1997, page 1.
---------------------------------------------------------------------------

    P092 Wastes--Phenylmercury acetate. P092 wastes consist of 
discarded phenylmercury acetate product, off-specification 
phenylmercury acetate product, and container or spill residues thereof. 
There are very little data available on the composition of P092 listed 
wastes. The primary constituent of P092 listed wastes is phenylmercury 
acetate; organic constituents (in particular, benzene) are also 
expected to be present.14 The use of phenylmercury acetate 
as a preservative in latex paint was phased out in 1991. Thus, the 
quantity of P092 waste is expected to decline dramatically as the stock 
of mercury-bearing paint is depleted.15
---------------------------------------------------------------------------

    \14\ U.S. EPA, BDAT Document for Mercury Wastes, November 1989, 
page 2-17.
    \15\ Mercury Treatment and Storage Options Summary Report, A.T. 
Kearney report for USEPA Reg 5, May 1997, page 1.

---------------------------------------------------------------------------

[[Page 28955]]

    U151 Wastes--Mercury. U151 wastes consist of discarded elemental 
mercury product, off-specification metallic mercury product, and 
container or spill residues thereof. The majority of U151 wastes 
reported as a single waste code (i.e., not mixed with other listed or 
characteristic wastes) in the EPA 1986 Generator Survey are over 50 
percent mercury. The principal constituent of U151 is metallic 
mercury.16
---------------------------------------------------------------------------

    \16\ U.S. EPA, BDAT Document for Mercury Wastes, November 1989, 
page 2-17.
---------------------------------------------------------------------------

B. Existing LDR Regulations for Mercury-Bearing Wastes

    Table 4 summarizes the current LDR requirements for these wastes.

                          Table 4.--LDR Regulations for Mercury-Bearing Nonwastewaters
----------------------------------------------------------------------------------------------------------------
                                             LDR treatment
                                             requirements
   Mercury Subcategory Description    -------------------------- Applicable waste codes      Federal Register
                                         Concentration in mg/l                                 publication
                                       TCLP; or Technology code
----------------------------------------------------------------------------------------------------------------
High Mercury-Organic Subcategory       Incineration (IMERC); OR  D009                    55 FR 22569,
 (i.e., the waste has a total mercury   Roasting or Retorting    P092                    (June 1, 1990).
 content greater than or equal to 260   (RMERC).
 mg/kg), contains organics, and is
 not an incinerator residue.
Mercury fulminate waste regardless of  IMERC...................  P065                    55 FR 22569,
 total mercury content and is not an                                                     (June 1, 1990).
 incinerator or RMERC residue.
Phenylmercury acetate waste            IMERC; OR RMERC.........  P092                    55 FR 22569,
 regardless of total mercury content                                                     (June 1, 1990).
 and is not an incinerator or RMERC
 residue.
High Mercury-Inorganic Subcategory     RMERC...................  D009                    55 FR 22569,
 (i.e., the waste has a total mercury                            K106                    (June 1, 1990).
 content greater than or equal to 260                            U151
 mg/kg), and is inorganic, including
 residues from incineration, roasting
 and retorting.
Low Mercury Subcategory (i.e., the     0.20 mg/l TCLP..........  D009 (a)                55 FR 22569,
 waste has a total mercury content                               K071                    (June 1, 1990).
 less than 260 mg/kg), and that are                              K106
 residues from RMERC only.                                       P065
                                                                 P092
                                                                 U151
 
Low Mercury Subcategory (i.e., the     0.025 mg/l TCLP.........  D009(a)                 55 FR 22569,
 waste has a total mercury content                               K071                    (June 1, 1990).
 less than 260 mg/kg), and are not                               K106                    D009 treatment standard
 residues from RMERC.                                            P065                     revised 63 FR 28568,
                                                                 P092                     (May 26, 1998).
Elemental mercury contaminated with    AMLGM...................  D009                    55 FR 22569,
 radioactive materials.                                          U151                    (June 1, 1990).
Hydraulic oil contaminated with        IMERC...................  D009                    55 FR 22569,
 Mercury Radioactive Materials                                                           (June 1, 1990).
 Subcategory.
----------------------------------------------------------------------------------------------------------------
a D009 wastes with concentration-based standards, rather than specified technology standards, must also meet
  Sec.  268.48 standards (LDR Phase IV final rule, May 26, 1998).

V. Mercury Treatment Technologies-Roasting and Retorting of Mercury 
Wastes

A. Process and Regulation

    Roasting or retorting of mercury (RMERC) and subsequently 
condensing the volatilized mercury for recovery is currently required 
for D009, K106, and U151 wastes in the high mercury-inorganic 
subcategory (i.e., 260 mg/kg total mercury and above), and P065 and 
P092 nonwastewaters that are incinerator residues or residues from 
roasting or retorting that still contain greater than 260 mg/kg total 
mercury. RMERC is also a treatment option for D009 wastes in the high 
mercury-organic subcategory that are not incinerator residues, and P092 
wastes that are not incinerator or RMERC residues.
    Most retort processes use a batch vessel. The mercury-bearing waste 
is sealed in the vessel and volatile gases, such as mercury vapor, are 
released when the vessel is heated (sometimes under vacuum conditions). 
The mercury vapor is condensed, collected, and subsequently purified by 
successive distillation. The BDAT Background Document 17 
also describes roasting, where air is introduced to the hot waste to 
oxidize mercury compounds and to help transport mercury vapor to the 
condenser.
---------------------------------------------------------------------------

    \17\ Final BDAT Background Document for Mercury-Containing 
Wastes D009, K106, P065, P092, and U151, USEPA, May 1990, page 3-2.
---------------------------------------------------------------------------

    All wastewater and nonwastewater treatment residues derived from 
the RMERC process must meet various standards that ensure proper 
mercury removal via RMERC. If treatment residues are still in the high 
mercury subcategory (i.e., contain 260 mg/kg total mercury or more), 
they must be retreated. If the RMERC treatment residues are in the low 
mercury subcategory (i.e., contain less than 260 mg/kg total mercury), 
they must meet a standard of 0.20 mg/L TCLP mercury prior to being land 
disposed. (Note: low mercury subcategory wastes that are not residues 
of RMERC must meet a more stringent standard of 0.025 mg/L TCLP 
mercury.) Thus, current LDR regulations mandate recovery (and therefore 
recycling) of mercury waste that contains greater than or equal to 260 
mg/kg total mercury; impose regulatory control over the emissions from 
roasting and retorting and the disposal of residues derived from the 
process; and differentiate between the residues from RMERC versus other 
treatment processes to encourage recycling and recovery. The Agency 
requests comment on whether RMERC should include types of recycling 
technologies other than roasting or retorting, which also would allow 
treatment residues from those technologies to be eligible for the 0.20 
mg/L standard.

[[Page 28956]]

B. Air Emissions from Roasting and Retorting

    Air emissions from a mercury retorting or roasting unit (or 
facility) also are regulated. The unit or facility must be subject to 
one or more of the following (40 CFR 268.42):
    (a) A National Emissions Standard for Hazardous Air Pollutants 
(NESHAP) for mercury;
    (b) A Best Available Control Technology (BACT) or Lowest Achievable 
Emission Rate (LAER) standard for mercury imposed pursuant to a 
Prevention of Significant Deterioration (PSD) permit; or
    (c) A state permit that establishes emission limitations (within 
meaning of section 302 of the Clean Air Act) for mercury.
    Secondary mercury production is estimated to have accounted for 
approximately 0.4 Metric tons of mercury emissions in 
1995.18 Air emissions from retorting or roasting units are 
generally scrubbed and passed through carbon filters that efficiently 
capture mercury vapor. When spent, these filters are retorted or 
roasted along with other wastes to recover the mercury that has been 
trapped. The units may also incorporate an afterburner prior to any 
additional air pollution control devices (APCDs) for odor control.
---------------------------------------------------------------------------

    \18\ Mercury Study Report to Congress, USEPA, December 1997, 
Volume I: Executive Summary, page 3-6.
---------------------------------------------------------------------------

(a) Chlor-alkali facilities
    Of the 14 chlor-alkali facilities using the mercury cell process, 
six conduct onsite retorting or roasting. The background document 
``Waste Specific Evaluation of RMERC Treatment Standard'' presents air 
emissions data for these six facilities from the TRI, and for two other 
facilities that do not conduct onsite mercury recovery. These two 
facilities ship their wastes off-site to other facilities owned by the 
same parent company. The releases shown represent all releases, 
including retorting emissions, fugitive emissions and emissions from 
hydrogen stream purification.19 The airborne mercury 
releases from all facilities with a retort process unit range from 250 
to 1,500 pounds for 1995. However, mercury releases from facilities 
without a retort process unit are comparable to the releases from 
facilities with retorters, indicating that retort emissions are 
relatively small compared to total facility emissions.
---------------------------------------------------------------------------

    \19\ Telephone conversation, Iliam Rosario, U.S. EPA, and John 
Vierow, SAIC, July 1998.
---------------------------------------------------------------------------

(b) Commercial Facilities
    The background document ``Waste Specific Evaluation of RMERC 
Treatment Standard'' contains data on mercury emissions to air, water, 
and offsite recycling sites for the three commercial roasting or 
retorting facilities that submitted TRI reports. No other emissions 
information is available for other facilities.
    Air emissions data for the three facilities indicate that releases 
are low. Stack emissions data were not obtained, but verbal 
correspondence indicates that measured emissions are also low. For 
example, one facility measures for mercury at the stack several times 
per day. A State official believed that these measurements are normally 
non-detects and, if any mercury is detected, the operation shuts 
down.20
---------------------------------------------------------------------------

    \20\ Telephone Conversation between John Vierow, SAIC, and Luis 
Pizarro, USEPA Region 3, June 1998.
---------------------------------------------------------------------------

    Detailed air pollution control device information is also available 
for several facilities. Air pollution control at several of the 
commercial roasting/retorting facilities includes carbon adsorption 
with no scrubbers.\21\ BRS data indicate that at least one facility 
uses carbon absorption and a scrubber. Literature reviews and 
discussions with technology vendors indicate that the use of activated 
carbon beds can achieve 90% or more mercury removal, with some greater 
than 99%.\22\
---------------------------------------------------------------------------

    \21\ Ibid.
    \22\ Draft Technical Support Document for HWC MACT Standards, 
USEPA, February 1996, F-96-RCSP-S0047.
---------------------------------------------------------------------------

    At one facility, all retorting and ancillary operations (e.g., 
material handling) are conducted indoors.\23\ This facility has 
emission controls for its furnace operation and for the building where 
the ancillary operations are conducted. The furnace off gas is cooled, 
then passed through activated carbon and a gas afterburner. Vent gas 
from the building passes through activated carbon and is emitted to the 
atmosphere. A second facility's furnace emissions are cooled, passed 
through a series of activated carbon absorption, and emitted to the 
atmosphere.\24\ A third company's retort process is contained in a 
multicompartment building and all of the operations are conducted under 
negative pressure to help control emissions. The facility also uses 
sealed rooms for the preheating and cooling of the mercury-bearing 
wastes, and the rooms are equipped with their own carbon adsorption 
filters to trap mercury vapor.\25\
---------------------------------------------------------------------------

    \23\ Bethlehem Apparatus, Waste Analysis and Recycling Plan, 
1996.
    \24\ Telephone Conversation between John Vierow, SAIC, and Luis 
Pizarro, USEPA Region 3, June 1998.
    \25\ Mercury Refining Company, Facility Information Packet.
---------------------------------------------------------------------------

    The Agency requests additional data on air emissions from roasting 
and retorting units, including information detailing the effectiveness 
of existing after burner, carbon bed, and scrubber controls.

C. Request for Comment

    The Agency specifically requests comment on the following:
1. What Wastes Are Not Amenable to RMERC?
    Mercury recovery facilities are exempt from the boiler and 
industrial furnace requirements of 40 CFR part 266, subpart H provided 
they meet certain requirements, such as the rejection of wastes with 
greater than 500 ppmw of certain organic constituents (i.e., organic 
compounds on 40 CFR part 261, appendix VIII). However, these units may 
process wastes containing various plastics, which may require the 
thermal destruction of odor causing emissions resulting from the 
pyrolysis (i.e., thermal decomposition) of these plastics. See appendix 
XIII of part 266. Other problem wastes for mercury recycling include:
     Wastes containing organic forms of mercury (e.g., mercury 
fulminate, phenylmercury acetate). Independent of regulatory 
restrictions, some facilities do not accept any organomercury compounds 
because the compound does not decompose into elemental mercury. 
Instead, the compound is carried through the retort and distillation 
system and results in an impurity in the final mercury product.\26\
---------------------------------------------------------------------------

    \26\ Frederick J. Manley, USPCI Lab Pack Manager, letter to EPA, 
July, 2, 1992.
---------------------------------------------------------------------------

     Wastes with a high water content. Large quantities of 
generated steam interfere with the mercury condensation process. To 
solve this problem, one facility precipitates or concentrates liquid 
solutions prior to retorting.
     Wastes containing mercuric chloride, polyvinyl chloride, 
and halogens. Mercury chloride and other salts carry over during the 
retorting and condensation process, forming impurities.\27\ 
Additionally, in the presence of steam, halogens will form acids, which 
corrode equipment. One facility pre-treats corrosive solutions using 
ion-exchange to overcome this problem. Another company uses chemical 
conversion to mercuric oxide prior to retorting to remove halides 
before processing.
---------------------------------------------------------------------------

    \27\ Ibid

---------------------------------------------------------------------------

[[Page 28957]]

     Wastes containing volatile metals. Some retorting 
facilities restrict certain metals, including lithium, arsenic, and 
thallium. It is not known why these self-imposed restrictions exist.
     Radioactive wastes. For regulatory and safety reasons, 
most facilities reject radioactive wastes. Only one facility has been 
identified that accepts radioactive mercury-bearing wastes.
     Mercury nitrate/nitrite solutions. This material typically 
results in an ignitable solution, which appears to raise permit 
concerns for facilities\28\
---------------------------------------------------------------------------

    \28\ Ibid
---------------------------------------------------------------------------

     Wastes containing mercuric sulfide. These wastes are 
difficult to retort. Additives are required to scavenge elemental 
sulfur produced before it can recombine with the mercury.
    The Agency requests further information detailing the problems that 
occur when treating wastes in retorting units, including the forms of 
mercury wastes that are not technically amenable to retorting and/or 
are not accepted at retorting facilities.
2. Should Non-Thermal Recycling Technologies Be Allowed for High 
Mercury Wastes and, if so, Should They Continue To Be Subject to a More 
Stringent Residual Standard?
    Since the RMERC regulations were promulgated, additional recycling 
technologies have been developed. One such technology is Universal 
Dynamic's REMERC process. While this process accomplishes mercury 
recycling in a closed system that limits air emissions, the residues 
are currently subject to the more stringent 0.025 mg/L TCLP mercury 
standard for non-RMERC residues. The Agency requests comment and data 
to determine whether non-RMERC recycling processes, if properly 
designed and operated, should continue to be under more stringent 
regulation because these processes may result in less mercury recovery 
than roasting and retorting processes, increased mercury content of 
residuals, higher air emissions, or a less stable final waste form. If 
these alternative recycling technologies are determined to be viable 
and are demonstrated to be properly designed and operated, the 
residuals could be subject to the current RMERC residual standard of 
0.20 mg/L, or to a new treatment standard that the alternative 
technology has been demonstrated to achieve. Alternatively, the current 
regulations could be expanded to include recycling technologies other 
than RMERC as potential options for treating high mercury subcategory 
wastes.
3. Should the Mercury Concentration Requirement for RMERC (260 mg/kg or 
above) Be Adjusted?
    The Agency requests data to support the potential adjustment of the 
260 mg/kg total mercury distinction between the high and low mercury 
subcategories. The Agency requests data on difficult to treat wastes, 
particularly ones that have required one or more processings to achieve 
a total mercury concentration of less than 260 mg/kg, and on initial 
total mercury content and total mercury content after each treatment, 
together with the associated analytical quality assurance measurements 
and operation and design parameters of the unit. The Agency reminds 
commenters submitting data in support of their views to include with 
the data evidence that appropriate quality assurance/quality control 
\29\ (QA/QC) procedures were followed in generating the data. Data that 
the Agency cannot verify through QA/QC documentation may be given less 
consideration or disregarded in developing regulatory options for 
proposed and final rules. Also, it is important that commenters 
demonstrate their processes were optimized and under stable operation 
during the test period. The Agency also requests information from 
retorting facilities concerning the minimum, maximum, and average 
concentration levels of mercury wastes accepted at these facilities.
---------------------------------------------------------------------------

    \29\ For guidance, see Final Best Demonstrated Available 
Technology (BDAT) Background Document for Quality Assurance/Quality 
Control Procedures and Methodology; USEPA, October 23, 1991.
---------------------------------------------------------------------------

4. Should the Agency Allow Alternative (Non-Recycling) Treatment 
Options to RMERC for High Mercury Wastes?
    The Agency requests comment on whether treatment options besides 
recovery should be permissible for high mercury subcategory wastes. 
Recycling mercury in industrial processes and using recycled mercury as 
a raw material for commercial products are potential sources of mercury 
releases into the environment. Because mercury releases to the 
environment have had adverse impacts on both human health and the 
environment, federal regulations have concentrated on controlling and, 
in some cases, phasing out mercury use in industry. At least in part, a 
result of these findings and actions has been a decline in the use of 
mercury in U.S. industry over the years.
    Therefore, the Agency seeks information on technologies that will 
treat high mercury wastes into a safe environmental form so that all 
mercury release pathways into the environment are minimized. The Agency 
requests comment on whether alternative land disposal treatment 
technologies to recovery (e.g., sulfide conversion and stabilization 
with sulfur-polymer cement) for high mercury wastes should be made an 
option and requests data on mercury releases from wastes treated by 
these technologies. Data and information should also be included on the 
technology's ability to treat wastes containing organics, and the 
maximum organic level that the technology can handle.
    One waste form that deserves particular mention is waste containing 
mercuric sulfide. These wastes are difficult to retort efficiently, and 
additives are required to react with or otherwise bind the elemental 
sulfur to prevent its recombination with the elemental mercury being 
recovered. As an alternative, precipitation of mercury using sulfide is 
a technology commonly applied in wastewater treatment. The Agency 
requests comment and data on whether such wastes should be either 
exempt from the RMERC requirement, subject to numerical standards, or 
subject to another technology standard.
5. Can Emissions From Secondary Mercury Production Be Further Reduced?
    While the roasting/retorting processes effectively recycle mercury 
and have air emission controls, an estimated 0.4 Metric tons/yr of air 
emissions from secondary mercury production still exists. The Agency 
requests comment on the feasibility of more efficient controls during 
secondary mercury production and on the use of enclosed treatment 
processes.
6. Should EPA Consider Revising the Debris Standards To Require That 
High Mercury Subcategory Wastes That Also Meet the Definition of Debris 
Be Retorted?
    The debris standards for hazardous wastes are listed in Table 1 of 
40 CFR 268.45. EPA requests comment on potential revision of these 
standards to require the roasting or retorting of hazardous debris if 
the mercury concentration is greater than or equal to 260 mg/kg total 
mercury. EPA dealt with a specific case of mercury debris in early 1997 
involving Aid-to-Navigation (ATON) batteries, and the most appropriate 
treatment and disposal method. At that time, EPA stated that it is more 
appropriate to apply the debris standards than the non-debris standards 
for mercury wastes, the latter of which would require RMERC (if the 
wastes contain 260 mg/kg or more total

[[Page 28958]]

mercury). However, in subsequent discussions with members of the 
recycling industry, the Agency was informed that retorting is indeed 
feasible on these types of wastes. We are seeking comments on whether 
the debris standard should be revised to require RMERC if the waste is 
in the high mercury subcategory. Commenters are encouraged to also 
include the possible ramifications of such a revision.

VI. Mercury Treatment Technologies--Incineration of Mercury Wastes

A. Current Regulations

    Three categories of waste streams must or can be incinerated under 
the current LDR treatment standards. These three are: D009 high 
mercury-organic subcategory; P092 wastes regardless of total mercury 
content that are not incinerator residues or are not residues from 
RMERC; and P065 wastes regardless of the total mercury content that are 
not incinerator or RMERC residues. The current regulations specify that 
incineration (IMERC) must be performed in units operated in accordance 
with the technical requirements of 40 CFR part 264, subpart O and 40 
CFR part 265, subpart O.\30\ All wastewater and nonwastewater residues 
derived from this treatment process must then comply with the 
corresponding treatment standards per waste code, with consideration of 
any applicable subcategories.
---------------------------------------------------------------------------

    \30\ 40 CFR 264 subpart O and 265 subpart O are the regulations 
for hazardous waste incinerators.
---------------------------------------------------------------------------

B. Characteristics of Mercury in Incinerators and Current Emission 
Control Systems

    Mercury is slightly volatile at ambient temperatures but is quite 
volatile at temperatures common to thermal treatment devices. It boils 
at approximately 356 degrees Celsius and typically escapes with other 
stack gases from incineration. With respect to mercury behavior in 
combustion systems and existing control techniques, mercury is 
volatilized and converted to elemental mercury in the high temperature 
regions of furnaces. As the flue gas is cooled, elemental mercury is 
oxidized to ionic forms. Elemental mercury, mercuric chloride, and 
mercuric oxide are all in the vapor phase at flue gas cleaning 
temperatures and special methods must be used for their capture. Each 
of these forms of mercury can be adsorbed onto porous solids such as 
fly ash, powdered activated carbon, and calcium based acid gas sorbents 
for subsequent collection in a particulate matter control device. Only 
one hazardous waste incinerator (WTI, Inc., East Liverpool, Ohio) 
currently has this type of APCD installed. Control of mercury in 
municipal waste combustors has been based on injection of powdered 
activated carbon upstream of an electrostatic precipitator or fabric 
filter, and many municipal units have this type of system installed.
    Mercury compounds also can be captured effectively using activated 
carbon or other sorbents. Fixed bed, fluidized bed, and duct injection 
arrangements have all been demonstrated to perform at 90% or more 
mercury removal efficiency, with some as high as 99% or greater. 
Systems without carbon injection, i.e., wet scrubbing systems designed 
for acid gases like hydrochloric acid, have much poorer mercury capture 
efficiency ranging from 0 to 40%. The highest control levels for 
activated carbon systems are achieved by optimizing the carbon type and 
the critical operating parameters of the control system. For example, 
for activated carbon injection, these parameters would include carbon 
feedrate, injection location, and temperature.\31\
---------------------------------------------------------------------------

    \31\ Draft Technical Support Document for HWC MACT Standards, 
USEPA, February 1996, F-96-RCSP-S0047.
---------------------------------------------------------------------------

C. Amount of Mercury Emitted from Incinerators and Other Hazardous 
Waste Combustors

    As part of our current MACT rulemaking to upgrade emission 
standards for hazardous waste incinerators and hazardous waste-burning 
cement kilns and lightweight aggregate kilns (collectively known as 
hazardous waste combustors), the Agency developed a database containing 
detailed information on hazardous waste emissions, including mercury. 
The database also includes information on the quantity of mercury in 
each feedstream fed to the combustion unit. These feedstreams include, 
if applicable, the hazardous waste, coal and other conventional fuels, 
and raw materials.
    Table 2, which is presented earlier in this preamble, shows 
national emission estimates for hazardous waste combustors for 1990, 
1994 and 1997. In 1990, mercury emissions from these sources totaled 
approximately 6.4 metric tons per year. Table 2 shows a further 
breakdown of the mercury emissions contribution from each hazardous 
waste combustor category. For 1994, national emissions from hazardous 
waste combustors were estimated to be approximately 6.4 metric tons per 
year. These sources are estimated to contribute approximately 4.4 
percent of the total anthropogenic, or man-made, emissions of mercury 
in the U.S. For 1997, mercury emissions from hazardous waste combustors 
total approximately 6.0 metric tons per year. In general, mercury 
emissions from hazardous waste combustors have decreased slightly 
between 1990 and 1997.32
---------------------------------------------------------------------------

    \32\ When interpreting any apparent data trends in Table 2, you 
should note that differences in emissions estimates are due to a 
combination of factors including actual data from performance in the 
field, revisions to our estimation methodology, and changes in the 
number of facilities operating within each category. See documents 
noted as sources for Table 2.
---------------------------------------------------------------------------

D. General Waste Characterization Data on Mercury in Hazardous Waste 
Streams

    Treatment capacity determinations for the LDR program are generally 
made based upon the broader Biennial Report System database, which 
covers all types of hazardous waste activities. If we were to amend our 
LDR treatment standards in any respect, we would also consult this 
database. The 1995 Biennial Report indicates that for mercury-bearing 
wastes, 86,400 tons were incinerated and 380,000 tons were reused as 
fuel (i.e., sent to cement kilns and light weight aggregate kilns). 
However, the BRS system itself does not distinguish between the high 
and low mercury subcategories, nor does it show what concentration of 
mercury is present in these waste streams.
    D009 wastes are extremely variable in composition, and their 
characteristics depend on the industry and process that generate the 
waste. Mercury concentrations in D009 wastes can range from 0.2 ppm to 
greater than 75 percent of the total waste composition. Although 
characterization data for D009 wastes are limited, some conclusions can 
be made regarding potential treatability issues. According to the 1995 
BRS, the three largest volumes of D009 waste by waste form were 
reported as ``halogenated/nonhalogenated solvent mixture'' (21,700 
tons), ``other halogenated solids'' (8,400 tons), and ``concentrated 
solvent-water solution'' (4,700 tons). These waste form descriptions 
suggest that the mercury is not the primary contaminant in the wastes. 
Finally, because concentration data are not provided in the BRS, D009 
wastes could be comprised of both high and low mercury subcategory 
wastes.
    Certain D009 waste streams may be incinerated for reasons other 
than the LDR IMERC treatment requirement. For example, BRS waste 
streams containing

[[Page 28959]]

hazardous materials, particularly dioxins and PCBs, as well as certain 
ignitables and reactives require incineration treatment. Incineration 
and other types of combustion are the only common treatment methods 
that completely destroy dioxins and PCBs. Therefore, many of the waste 
streams reported to the 1995 BRS may have to be processed using 
incineration regardless of the mercury content. Many waste streams 
contain D009 mercury organic-bearing wastes from lab packs, 
halogenated/nonhalogenated solvent mixtures, certain halogenated 
solids, oily sludges, and organic paints.
    No waste characterization data were found for P065 listed wastes. 
Two facilities in the 1995 BRS reported incineration of P065.
    Very little data are available on the composition of P092 listed 
wastes. The primary constituent of P092 listed wastes is phenylmercury 
acetate; organic constituents (in particular, benzene) are also 
expected to be present (USEPA 1989). Five facilities in the 1995 BRS 
reported incineration of P092.

E. EPA's Re-Evaluation of the IMERC Standard

    As discussed earlier, the current LDR regulations require or allow 
incineration of three types of waste streams, most notably D009 wastes 
that contain mercury above 260 mg/kg and that also contain some 
organics (i.e., the high mercury organic subcategory). The two original 
premises behind IMERC were that: (1) incineration would destroy the 
organic component or organomercury complexes in the waste stream, and 
the residues, if greater than 260 mg/kg total mercury, would be 
retorted to recover the mercury; and (2) applicable regulatory controls 
would provide adequate control of mercury air emissions.
    With respect to the premise that mercury would be recovered from 
incineration systems, either incinerator bottom ash residues or 
emission control residues (e.g., spent activated carbon, scrubber 
sludges) could be sent to mercury recovery units. Incinerator bottom 
ash is likely to contain little mercury, however, because mercury is 
easily volatilized to the combustion gas. In addition, incinerators 
generally are not equipped with emission control equipment that removes 
mercury from combustion gas. In fact, the latest BRS report shows no 
record of incinerator residuals going to mercury recovery units. As a 
practical matter, although incineration destroys the organics, it does 
not make the mercury particularly amenable to recovery. It is therefore 
difficult to regard incineration as contributing to the recovery of 
mercury, which was one of our original premises.
    With respect to the second premise that applicable regulatory 
controls would provide adequate control of mercury emissions from 
incineration, neither the incinerator or BIF regulations nor the LDR 
regulations specifically require the use of emission control devices 
that effectively capture mercury (e.g., activated carbon). As 
implemented in practice, the BIF regulations and some incinerator 
permits restrict mercury in the hazardous waste feed. Because feed 
restrictions are not so stringent as to eliminate mercury in the 
feedstream and because the current regulations do not require the use 
of emission control devices that efficiently capture and remove 
mercury, it is still emitted to the atmosphere.33
---------------------------------------------------------------------------

    \33\ Mercury emissions can also be controlled under special 
conditions imposed through RCRA omnibus authority. See 
Sec. 270.32(b).
---------------------------------------------------------------------------

    While the recently proposed (61 FR 17358, April 19, 1996) Hazardous 
Waste Combustor Maximum Achievable Control Technologies (MACT) 
regulations will impose some emission limitations on mercury emissions 
from hazardous waste incinerators, cement kilns, and lightweight 
aggregate kilns, these regulations are unlikely to require the capture 
and recovery of mercury from the combustion emissions or other 
combustion residuals. Thus, the implementation focus at individual 
combustion facilities is expected to continue to be controlling 
feedrate levels of mercury-bearing hazardous waste into the combustion 
device. The Agency is likely to determine under the final MACT rule 
that requiring specific APCDs on hazardous waste combustors to capture 
mercury is not cost-effective.
    Although feed restrictions can and do reduce mercury emissions and 
to some extent the associated risks, we are still concerned with the 
environmental loading of mercury. The MACT rule does not take into 
account the long-range transport of mercury emissions, and 
uncertainties in the HWC MACT risk assessment allow the Agency to 
conclude only that risks from mercury emissions within 20 kilometers 
are likely to be small.34 The Agency wishes to consider 
whether we can further reduce the environmental loading by amending the 
LDR regulations to reduce the volume of mercury wastes that require 
IMERC and to promote the use of alternative treatment methods.
---------------------------------------------------------------------------

    \34\ ``Risk Assessment Support to the Development of Technical 
Standards for Emissions from Combustion Units Burning Hazardous 
Wastes: Background Information Document,'' February 20, 1996.
---------------------------------------------------------------------------

    Thus, the IMERC standard bears further investigation to see 
whether, given the heightened concern over all sources of mercury 
emissions, even ones at relatively low levels, alternative LDR 
approaches may be appropriate to ensure better protection of human 
health and the environment. We note that EPA must address any 
significant remaining residual risks posed by sources subject to the 
MACT technology-based standards within eight years after promulgation 
of the Hazardous Waste Combustor MACT standards. See section 112(f)(2). 
The Agency is required to impose additional controls if such controls 
are needed to protect public health with an ample margin of safety, or 
to prevent adverse environmental effects. Our mercury reevaluation in 
this proceeding is also expected to assist EPA in any residual risk 
evaluation.

F. Additional Considerations Related to Alternatives to Incineration

    A possible alternative to incineration for some mercury-bearing 
wastes is the physical separation of the mercury containing and organic 
components of the waste streams. Mercury retorters report that mercury-
bearing organic wastes may be separated prior to treatment, when the 
mercury is associated with particulates in the waste. After retorting 
of the particulates, the retort condenser sludge is separated and 
returned to the retorting process for additional mercury recovery. The 
residual organic phase with reduced mercury content is then 
incinerated. While such waste separations may be feasible for organic 
wastes containing inorganic mercury, such separations would likely not 
work for organomercury wastes. Thermal or other destruction of the 
organomercury compounds present appears to be needed to convert the 
organomercury compounds to a recoverable form, as was originally 
envisioned in the IMERC standard.

G. Request for Comment

    The Agency has several potential concerns with the IMERC standard. 
Specifically, from the available combustion database and the BRS data, 
it appears that non-trivial volumes of mercury-bearing waste are going 
to combustion units. As discussed above, because mercury is a volatile 
metal and unless the combustion unit has an APCD capable of capturing 
mercury emissions (normally not the case), potentially all of the 
mercury fed into

[[Page 28960]]

the unit will be vaporized and released into the atmosphere.
    The Agency specifically requests comment on the following:
1. What Mercury Waste Streams Will Continue to Warrant IMERC?
    There may be wastes for which incineration is the best available 
treatment option, for example, wastes with low mercury concentrations 
and high levels of organics, mercury wastes containing PCBs, and 
mercury wastes containing or combined with reactive and ignitable 
hazardous waste. In an attempt to identify such wastes, the Agency 
examined BRS data for wastes that are D009 and also contain dioxins or 
PCBs. A search of the 1995 BRS data showed only one hazardous waste 
incinerator that processed waste streams containing both D009 wastes 
and dioxin wastes. (EPA hazardous waste codes F020-F023 and F026-F028). 
According to the 1995 BRS, the facility processed approximately 80 tons 
of wastes containing dioxins from 27 separate waste streams. Many of 
these wastes are from soil and debris from facility decommissioning. 
However, no concentration data were available. Three facilities process 
waste streams containing both D009 wastes and PCB wastes. These 
facilities processed approximately 446 tons of wastes from 22 separate 
waste streams in 1995. Most of the PCB wastes were organic solids and 
sludges and again, no concentration data were available. Waste streams 
containing reactive and ignitable hazardous wastes covered a wide 
variety of waste stream codes. Many of the ignitable and reactive 
wastes were flammable liquids, solvents, and petroleum. In addition, it 
appears there are other waste streams, such as oily wastes, that 
require incineration.
    However, inorganic mercury is generally associated with solids in 
highly organic wastes. These mercury-bearing solids can be separated by 
centrifuge prior to retorting. The Agency requests information on 
mercury-bearing wastes that may continue to require incineration, and 
on wastes that would be amenable to the separation of mercury solids 
for recovery prior to incineration of the remainder of the waste. 
Specifically, the Agency requests comment on the feasibility of 
requiring the separation of mercury-bearing solids from organic wastes 
and identification of any wastes for which such pretreatment would not 
be feasible.
2. What Alternative Technologies Are Available To Treat Mercury Wastes 
Containing Organics While Also Minimizing Mercury Emissions?
    Because mercury emissions from incinerators may be costly to 
control, alternative technologies are sought that can either recycle 
the mercury in the wastes, separate the mercury from the organics prior 
to incineration of the organics, or produce a stable residue for 
disposal that reduces the risks attributed to the organic and mercury 
constituents. The Agency seeks waste characterization and technology 
performance data on alternative technologies for the treatment of 
wastes that are currently incinerated.
    We also request information on the impediments to using alternative 
technologies, such as RMERC, to treat mercury wastes containing 
organics (RMERC is currently listed as an alternative in the 
regulations), and whether the organics can be destroyed or captured. 
Would an alternative technology such as an oxidation-leaching-
precipitation train be more desirable? What are the concentration 
limits of organics that could be treated by these alternative 
technologies? If these alternative technologies are shown to 
effectively treat mercury wastes containing organics, should the 
incineration standard then be retained only if the unit has appropriate 
APCDs to capture the mercury and/or only if the organics in the wastes 
are ``hard to treat?'' The Agency specifically requests comment and 
data supporting commenter's views on these issues. The Agency also 
requests information regarding the current capacity of alternative 
oxidation technologies.

VII. Regulatory Options Involving Source Reduction

    As discussed above, EPA's current LDR regulations set both 
technology and numerical based treatment standards that require waste 
management facilities to either retort, roast, or incinerate hazardous 
wastes that contain greater than 260 mg/kg of total mercury (depending 
on the presence of organics; see Table 4); or treat hazardous wastes 
that contain less than 260 mg/kg of total mercury to 0.025 mg/L TCLP 
prior to land disposal.
    Some companies have found ways to reduce or eliminate the amount of 
mercury in their waste by making changes in their production processes 
and plant management, including changing raw materials, equipment, 
process design, and maintenance activities. In some cases, these 
changes have taken several years to design, test and install, while 
simultaneously relying on costly treatment technology to remain in 
compliance. For example, chlor-alkali producers, which are the largest 
manufacturing users of mercury in the U.S., have historically relied on 
a mercury cell process to manufacture chlorine and caustic soda. 
Caustic soda produced from this process may contain mercury, which in 
turn may contaminate other products and generate mercury-bearing 
hazardous wastes. By 1994, approximately one-half of the chlor-alkali 
plants had changed to a membrane cell production process, which does 
not use mercury. The membrane cell process has resulted in better 
environmental results and lower energy and waste management costs for 
the facilities that use this technology.
    EPA wishes to consider regulatory options that produce superior 
environmental results and cost-savings for the regulated community 
beyond the requirements of end-of-pipe technology standards. EPA 
recognizes that once a company invests in end-of-pipe recovery or 
treatment technologies that meet compliance requirements, there may be 
little or no incentive to invest more money in process changes that 
would reduce or eliminate a particular hazardous waste, particularly 
since there would be no relief from waste management costs while 
process changes are being designed and tested.
    In today's document, EPA is seeking comment on potential regulatory 
incentives that would encourage companies to invest in manufacturing 
process redesign, raw materials substitution or other technologies that 
would reduce the amount of mercury found in hazardous waste. To make 
this approach incentive-based, EPA is seeking views and information on 
the possibility of extending LDR compliance dates for companies willing 
to develop and/or install technologies that could be used instead of, 
or in combination with, end-of-pipe technologies to reduce the 
generation of mercury-bearing hazardous wastes.
    One approach EPA is considering is a two-part LDR standard. The 
first part of this standard would be a traditional standard, developed 
from data on the best available treatment technologies. The second and 
novel part of the standard would be an alternative standard that 
facilities could elect in lieu of the first, more traditionally-based 
standard. This alternative standard would involve the installation of 
source reduction-oriented process changes that would either reduce the 
volume of mercury waste produced or the concentration of mercury in the 
wastes. As an incentive for encouraging

[[Page 28961]]

companies to comply with the alternative standard (particularly if the 
mercury concentration level is lower than the level for the first part 
of the standard), EPA would extend the generator exclusion from 
permitting beyond the current 90 days, or provide some other kind of 
incentive.
    EPA is seeking comment on the development of a two-part standard, 
like the one discussed above, or another standard that provides 
economic or regulatory incentives to promote source reduction of 
mercury in hazardous wastes. EPA would also like comment on whether 
extending the compliance dates would foster reductions in wastes beyond 
the limits achievable using end-of-the pipe treatment technologies.

VIII. Mixed Wastes

    Ongoing inventory of mercury-contaminated wastes currently awaiting 
disposal at Department of Energy (DOE) facilities has identified 7,284 
cubic meters of such wastes. These wastes are the legacy of past 
nuclear weapons production for national defense. Table 5 presents an 
inventory of this waste.

          Table 5.--Mercury Containing Wastes at DOE Facilities
------------------------------------------------------------------------
                                                              Inventory
                          Category                              (cubic
                                                               meters)
------------------------------------------------------------------------
Elemental..................................................           17
<260 mg/kg.................................................        6,000
>260 mg/kg.................................................          325
Unknown....................................................          942
------------------------------------------------------------------------
    Total..................................................       7,284
------------------------------------------------------------------------
Source: DOE Mercury Working Group, 1999.

    Under current regulations, no separate treatment category exists 
for high mercury wastes that also contain radioactive materials. 
Therefore, the regulations direct that high mercury-organic subcategory 
mixed wastes be subjected to RMERC or IMERC and that high mercury-
inorganic subcategory mixed wastes be subjected to RMERC. At the time 
of promulgation, these regulations intended that the mercury be 
separated from the wastes and recycled. However, with the cessation of 
nuclear weapon production, there are no longer any uses for mercury 
that is still contaminated with radioactive materials. Thus, current 
regulations may result in the contamination (by radiation) of 
additional equipment to recover mercury that has no subsequent use and 
for which the treatment standard for disposal is again RMERC. 
Department of Energy's (DOE) Mixed Waste Focus Area-Mercury Working 
Group, in conjunction with EPA, has initiated studies of the direct 
treatability of high mercury-inorganic subcategory wastes for direct 
disposal. Should these tests demonstrate the successful treatment of 
such wastes, EPA could, as part of this or a separate LDR rulemaking, 
create a separate subcategory for these mercury-bearing mixed wastes 
and potentially develop a numerical treatment standard for the 
subcategory. These treatability studies include the evaluation of 
technologies such as alternative oxidation technologies, stabilization 
using specialized amendments, amalgamation technologies, sulfur polymer 
cement stabilization, and mercury solubilization and removal. Further 
information on these technologies is located in the docket to today's 
ANPRM. The Agency expects that several of these studies will be further 
along by the time of a proposed rule (scheduled to follow this ANPRM by 
approximately one year). Any available data from these tests will be 
discussed in the proposed rule and placed in the docket to that rule.
    The Agency specifically requests comments on eliminating the RMERC 
standard for mixed mercury wastes, and on allowing the use of 
alternative technologies that are currently being investigated by EPA 
and DOE, with the residuals having to comply with a numerical limit.

IX. Discussion of Alternative Treatment Technologies

A. Possible Alternative Technologies to Retorting

    As discussed in the May 1990 Best Demonstrated Available Technology 
(BDAT) Background Document for Mercury Containing Wastes, retorting is 
not the only technology that has been used in treating high mercury 
wastes. Alternative treatment technologies are categorized as either 
removal/recovery technologies or immobilization technologies. These 
alternatives are presently used, or could potentially be used for 
treating such wastes.
    Alternative treatment technologies presently exist, or have existed 
in the past, for two reasons. First, the alternative technology may be 
simply another competing process to remove mercury from, or fix mercury 
within, a matrix. Second, the technology may overcome restrictive waste 
characteristics that cause difficulty during retorting or roasting. For 
example, several processes are actually ``pretreatment'' processes to 
prepare the waste for retorting. These processes remove waste 
characteristics that restrict treatment, such as water content, and 
convert mercury compounds into easier to treat forms.
    Several technologies which may hold some promise for the treatment 
of high mercury wastes include the following:
Removal/Recovery Technologies
    (1) Acid/chemical leaching (solids, slurries, or aqueous wastes). 
The mercury is converted to a more soluble form and thus is removed 
from the waste matrix.
    (2) Carbon adsorption (aqueous wastes or vapors). Mercury retort 
facilities commonly use carbon adsorption as a way of removing and 
concentrating mercury removed from stack gas or effluents.
    (3) Ion exchange. Ions in the exchange resin are substituted for 
mercury ions of similar charge.
    These technologies are described in more detail in the background 
document ``Waste Specific Evaluation of RMERC Treatment Standard.''
Immobilization Technologies
    (1) Solidification/stabilization (solids or slurries). 
Solidification/stabilization(S/S) processes are nondestructive methods 
to immobilize the hazardous constituents in a matrix while decreasing 
the waste surface area and permeability. 35 Common S/S 
agents include Type 1 Portland cement, lime, and fly ash. The final 
product can be a monolith of any practical size or a granular material 
resembling soil. 36 Sulfur polymer cement (SPC) is one 
stabilization technology that can be used to convert mercury compounds 
to mercuric sulfide and encapsulate simultaneously (U.S. DOE, 1998). 
However, the encapsulation process temperatures can volatilize mercury, 
so the mercury vapor and oxide that forms must be captured and recycled 
in the process.
---------------------------------------------------------------------------

    \35\ U.S. EPA, Technical Resource Document: Solidification/
Stabilization and its Application to Waste Materials, EPA/530/R-93/
012, June 1993.
    \36\ U.S. EPA, Engineering Bulletin: Solidification/
Stabilization of Organics and Inorganics, EPA/540/S-92/015, February 
1993.
---------------------------------------------------------------------------

    (2) Amalgamation. Amalgamation typically involves the mixing of 
elemental mercury with a powdered granular metal (typically zinc), 
forming a non-liquid, semi-solid matrix of elemental mercury and the 
metal. Two generic processes that are used for amalgamating mercury in 
wastes are an aqueous replacement (solution) process, and a non aqueous 
process.37
---------------------------------------------------------------------------

    \37\ U.S. EPA, Treatment Technology Background Document, January 
1991, pages 74-80.
---------------------------------------------------------------------------

    The Agency requests more information, including any data from 
treatability studies and their

[[Page 28962]]

applications to various waste matrices, on these technologies.

B. Possible Alternative Technologies to Incineration

    This section discusses the treatment technologies that are being 
studied to treat high mercury wastes currently requiring incineration. 
The goal of these technologies is to achieve the same degree of 
destruction of the organic compounds as is achieved with incineration, 
while maintaining control over the residual mercury. Many variables 
need to be considered, including the degree of organic destruction 
required prior to further mercury treatment, the degree of mercury 
speciation control required by the waste form, and other operating 
procedures to ensure mercury extraction from nonwastewaters and 
wastewaters. Because the mercury cannot be destroyed, various treatment 
process steps are necessary to treat or recover the mercury, depending 
on the mercury species present in the waste, its concentration, and the 
overall waste form.
    Currently, the only common process capable of destroying organics 
is oxidation, which can be done thermally or chemically. It is usually 
combined with other technologies to form a treatment train. One such 
train is the oxidation, leaching, and precipitation train, which has 
been shown to be effective in treating high mercury wastes currently 
requiring incineration. Once the organics are destroyed, leaching and 
precipitation treat the inorganic mercury forms, such as oxides and 
hydroxides. The resulting waste is then suitable for retorting or 
immobilization prior to disposal. Note that this type of treatment 
train cannot destroy dioxins, furans, or PCBs.
    The Agency also has limited information on a number of developing 
technologies including nonthermal (i.e., Delphi DETOX (Delphi 
Research), Direct Chemical Oxidation (LLNL), Acid Digestion (Savannah 
River)) and thermal processes (such as steam reforming) (ThermoChem 
Inc.), and Catalytic Chemical Oxidation (LBNL)) under development in 
support of the waste treatment needs of the Department of Energy 
facilities. One or more of these technologies may soon be available and 
used for mercury-bearing wastes, followed by stabilization. EPA 
requests further information on the aforementioned technologies, as 
well as any others that may be used in place of IMERC.

C. Current Mercury Treatment Companies

    Several sources were researched to identify facilities and 
companies that provide alternative treatment for mercury-bearing 
organic wastes. These sources include BDAT capacity background 
documents, the 1995 Biennial Reporting System (BRS), Alternative 
Technology Treatment Information Center (ATTIC) database, Vendor 
Information System for Innovative Treatment Technologies (VISITT) 
database, technical background documents, online web searches for 
company and treatment technology profiles, and the Risk Reduction 
Engineering Laboratory (RREL) database. Limited information is 
available on vendors and facilities that treat mercury-bearing organic 
wastes using methods other than incineration or retorting. BRS data 
indicate that there are numerous facilities that treat mercury-bearing 
organic wastes. The BRS waste management code, the code used to report 
the final treatment of the waste, in a few cases indicated there is 
acid leaching or oxidation used to treat the mercury-bearing organic 
waste stream. This may be because the final treatment step is the only 
management code reported, and does not indicate if a multiple step 
process is used. The predominant treatments reported in BRS are 
stabilization/chemical fixation using cementitious and/or pozzolanic 
materials and phase separation. There are several data gaps that 
require further investigation on a process and waste stream specific 
level. In addition, the BRS data do not adequately describe the organic 
content of the actual waste stream being treated, especially where 
multiple waste form codes are reported together with the D009 code. A 
table listing the mercury treatment facilities is provided in the 
background document ``Analysis of Alternatives to Incineration for 
Mercury Wastes Containing Organics,'' which can be found in the docket 
to today's ANPRM.

D. Request for Comment

    The Agency seeks comments on the viability and parameters of these 
alternative technologies and any other technologies not specifically 
mentioned in this ANPRM. Specifically, the Agency seeks the following 
information: description of the process; types of wastes capable of 
being treated; total, leachable, and volatile mercury content of the 
wastes and of the residues following treatment; amount of mercury air 
emissions from treatment; operating conditions and parameters; data 
showing the efficiency of the technology; commercial availability of 
the technologies and their available capacity; limitations of the 
technologies; cost information for these alternative technologies; and 
other potential benefits of using these alternative technologies over 
the existing treatment technologies. All data submitted should have 
appropriate QA/QC documentation to ensure their consideration by the 
Agency. Data without QA/QC may be disregarded.

X. Possible Revisions to the Mercury LDRs

A. Purpose of ANPRM

    The Agency plans to examine potential revisions to the LDR mercury 
treatment standards, including the potential to encourage manufacturing 
process changes (i.e., source reduction changes) that further reduce 
the amount of mercury entering hazardous waste streams, as the next 
step in this rulemaking process. The Agency decided that this ANPRM is 
necessary before proposal development because the Agency would benefit 
from additional mercury treatment data, including information on source 
reduction opportunities, as well as industry information to consider in 
amending the standards. The nature and extent of these amendments have 
not yet been determined. This ANPRM is expected to be beneficial to the 
regulating entities (including States), the regulated community, and 
the public as a means of public outreach and opportunity for public 
comment early in the rulemaking process. EPA encourages all interested 
persons to submit comments, and to identify any relevant issues not 
addressed by this ANPRM. The Agency also welcomes comments regarding 
whether the LDR mercury treatment standards should be revised. The 
Agency encourages commenters to submit examples or documentation to 
support their positions. The input from public comment will assist the 
Agency in developing a proposed rule that successfully addresses all 
appropriate revisions to these standards. An Agency decision to issue a 
proposed rule to revise LDR mercury treatment standards and the nature 
of those revisions will be ultimately based on the comments received on 
this ANPRM, as well as data obtained from other sources (e.g., ongoing 
treatability studies).

B. Schedule

    The Agency has general plans to release a notice of proposed 
rulemaking by early 2000. The final rule date will depend on the amount 
of information submitted and the issues raised.

[[Page 28963]]

C. Impact on Small Businesses

    The Agency believes, at this point, that the impact on small 
businesses will not be significant. EPA requests comment on the 
potential costs and benefits to small businesses, should revisions be 
made to the LDR mercury treatment standards as described in this ANPRM. 
Suggestions on ways the Agency might mitigate any adverse effects would 
also be welcome.

D. Impact on State Programs

    The Agency will be cognizant of the impact of any proposed 
revisions to the LDR mercury treatment standards on State programs, and 
encourages comments on this subject.

XI. Administrative Requirements

A. Regulatory Flexibility Act

    The Regulatory Flexibility Act (RFA) generally requires an agency 
to conduct a regulatory flexibility analysis of any rule subject to 
notice and comment rulemaking requirements unless the agency certifies 
that the rule will not have a significant economic impact on a 
substantial number of small entities. Small entities include small 
businesses, small not-for-profit enterprises, and small governmental 
jurisdictions. This ANPRM will not have a significant impact on a 
substantial number of small entities because it does not create any new 
requirements. Therefore, EPA provides the following certification under 
the Regulatory Flexibility Act, as amended by the Small Business 
Regulatory Enforcement Fairness Act: Pursuant to the provision at 5 
U.S.C. 605(b), I certify that this action will not have a significant 
economic impact on a substantial number of small entities. However, 
there is the potential for future actions related to this ANPRM to have 
a significant economic impact on a substantial number of small 
entities. Therefore, the Agency will examine whether the Regulatory 
Flexibility Act applies in the preparation of any future rulemakings 
related to this ANPRM.

B. Executive Order 13045

    Protection of Children from Environmental Health Risks and Safety 
Risks (62 FR 19885, April 23, 1997), applies to any rule that: (1) is 
determined to be ``economically significant'' as defined under E.O. 
12866, and (2) concerns an environmental health or safety risk that EPA 
has reason to believe may have a disproportionate effect on children. 
If the regulatory action meets both criteria, the Agency must evaluate 
the environmental health or safety effects of the planned rule on 
children, and explain why the planned regulation is preferable to other 
potentially effective and reasonably feasible alternatives considered 
by the Agency.
    This ANPRM is not subject to E.O. 13045 because it is does not, at 
this point, involve decisions intended to mitigate environmental health 
or safety risks. Of course, as the information in response to this 
ANPRM is evaluated, we will continue to examine whether E.O. 13045 
applies.

List of Subjects in 40 CFR Part 268

    Environmental protection, Hazardous waste, Reporting and 
recordkeeping requirements

    Dated: May 21, 1999.
Carol M. Browner,
Administrator.
[FR Doc. 99-13659 Filed 5-27-99; 8:45 am]
BILLING CODE 6560-50-P