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Mixed Waste
Waste Management: 

Guidance on the Land Disposal Restrictions' Effects on Storage and Disposal of Commercial Mixed-Waste


The 1984 Hazardous and Solid Waste Amendments (HSWA) to the Resource Conservation and Recovery Act (RCRA) restrict the land disposal of hazardous wastes, including mixed-waste. This overview outlines the major aspects of the land disposal restrictions (LDR) as they apply to mixed-wastes.

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What is mixed-waste?

Mixed-waste is a waste mixture that contains both radioactive materials subject to the Atomic Energy Act (AEA) and a chemically hazardous waste component regulated under RCRA.

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What is the LDR legislative framework?

The 1984 HSWA amendments to RCRA prohibit the continued land disposal of untreated hazardous waste with the following exceptions:

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Which mixed-wastes are subject to the land disposal restrictions?

The LDR regulations apply to all hazardous waste, including mixed-waste, listed or identified under RCRA 3001.

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Do federal agencies have to comply with LDRs?

Section 3021(b) of RCRA, as amended by the Federal Facilities Compliance Act (FFCA), requires DOE to submit Site Treatment Plans (STP) for mixed-wastes so that they comply with RCRA regulations including LDR restrictions. All treatment technologies that DOE uses under the STPs must meet LDR requirements set forth in section 3004 of RCRA (Title 40 of the Code of Federal Regulations, Part 268, contains the applicable regulatory requirements).

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What are "Best Demonstrated Available Technologies"?

RCRA Section 3004(m) requires EPA to issue regulations and standards that result in reduced toxicity or likelihood of migration of the wastes. EPA issued treatment standards that relied on levels achieved by Best Demonstrated Available Technologies (BDAT).

Evaluating the performance of treatment processes for BDAT is based upon the concentration of specific constituents in treatment residuals in the land disposal environment. When establishing BDAT, EPA sets a standard for both the waste water and non-wastewater forms of a waste code. Often, EPA will set a standard for waste subgroups called "waste treatability groups" which consist of wastes with similar physical and chemical properties. EPA then determines what the demonstrated treatment technologies are for each "treatability group".

It is important to note that, in some cases, the specific technologies identified as the basis for BDAT are simply those technologies which EPA used to develop the waste-specific performance standard. Any technology or combination of technologies not otherwise prohibited can be used to achieve these standards. In other words, a specific treatment technology does not have to be used unless the specific method of treatment is specified as the treatment standard.

To date, EPA has set special treatment standards for four categories of mixed-waste. They include:

  1. radioactive lead solids with a BDAT treatment standard of macroencapsulation;
  2. radioactive elemental mercury with a BDAT treatment standard of amalgamation;
  3. radioactive hydraulic oil contaminated with mercury and a BDAT standard incineration and.
  4. radioactive high level wastes generated during the reprocessing of fuel rods with a BDAT standard of vitrification.

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What were the effective dates for the LDRs?

As soon as EPA sets a treatment standard, wastes subject to that standard are automatically prohibited from land disposal, unless the wastes meet the treatment standard or are disposed in an EPA approved no-migration unit (3004(h)(1)). EPA may through rule making revise a treatment standard after the statutory date. If wastes are generated that cannot be treated to the specified treatment levels or using the specified treatment methods, the regulations allow a generator or owner/operator to submit a petition to the Administrator requesting a variance from the treatment standard. Most variances are granted through a rule making which requires publication in the Federal Register and public comment.

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What are the rules for obtaining variances for mixed-waste LDRs?

"No Migration" Extension

EPA will consider petitions to allow land disposal of prohibited wastes that do not meet the treatment standard, provided the petitioner demonstrates that there will be no migration of hazardous constituents from the disposal unit or injection zone for as long as the waste remains hazardous (40 CFR 268.6).

Variances from the Treatment Standards

EPA recognizes that some mixed-waste might not be treatable by the method or to the level specified in the regulations. In such situations, EPA will allow petitions to be submitted requesting a variance from the treatment standard. If granted on a national basis, these variances result in the establishment of a new treatability group and new treatment standards for all wastes in the treat ability group. Variances may also be granted on a site-specific basis. Site specific variances may be granted administratively (i.e., without notice-and comment rulemaking) and have no generic application to similar wastes generated at other sites.

Variance petitions should be sent to the U.S. EPA Administrator and the Office of Solid Waste (see 40 CFR 268.44).

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What are the LDR waste testing and record keeping requirements?

Generators must test or use their knowledge of the prohibited hazardous waste to demonstrate compliance with the LDR treatment standards or California prohibition Levels prior to land disposal (see 40 CFR 268.7). Generators who treat prohibited wastes in 90 day tanks or containers to meet treatment standards, must treat these wastes at a frequency specified in their waste analysis plan. Similarly, treatment and disposal facilities are required to treat their wastes according to the frequency defined in the facility waste analysis plan.

Each time a restricted waste is shipped to an off-site treatment, storage or disposal facility, notification must accompany the waste. If a waste meets a treatment standard, then certification by the generator or treatment facility is required verifying that the treatment standard has been achieved and the waste has not been impermissibly diluted. (Certain record keeping requirements also apply to restricted wastes that remain on-site, cease to be solid or hazardous wastes and arc not land disposed.)

Notification and certification are not required to accompany characteristic wastes rendered nonhazardous to Subtitle D facilities. However, appropriate notification and certification for these wastes must be sent to the EPA Regional Administrator or authorized State. If the characteristic wastes rendered non-hazardous arc sent to a Subtitle C Facility, then the appropriate notification and certification must be sent to the Subtitle C facility. Note that a one-time notification and certification is allowed for small quantity generator shipments subject to tolling agreements outlined in 40 CFR 262.20(e)(2).

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Treatment in Surface Impoundment Exemption

Treatment of wastes that are normally prohibited from land disposal is allowed in a surface impoundment or a series of surface impoundments that meet the technological requirements of 40 CFR 268.4(a)(3). After treatment, if the residues do not meet the applicable treatment standard (or statutory prohibition level if the treatment standard has not been established), then the residues must be removed for subsequent management within a year of entry into the unit and may not be managed in another surface impoundment. Also, a certification that attests that the technical requirements arc met and a modified waste analysis plan that incorporates 40 CFR 268.4 residual testing requirements must be sent to the Regional Administrator.

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Dilution as Treatment

Under the LDRs, dilution is prohibited as treatment for both listed and characteristic wastes (see 40 CFR 268.3). However, exceptions to the prohibition were made for:

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What is the LDR storage prohibition?

In addition to prohibiting the land disposal of hazardous wastes, Congress also prohibited the storage of any waste which is prohibited from land disposal unless "such storage is solely for the purpose of the accumulation of such quantities of hazardous waste as are necessary to facilitate proper recovery, treatment, or disposal" [RCRA Section 3004(j)]. The intent of Congress was to ensure that long-term storage was not used as a means of avoiding a land disposal prohibition.

The implementing regulations that address the prohibitions on storage of LDR waste are found in 40 CFR 268.50. This regulation essentially restates the statutory language.

A few exemptions permit storage of LDR waste in tanks or containers:

Wastes that were disposed of prior to the LDRs, but removed from the land disposal area after the LDRs became effective are subject to storage requirements.

Facilities may accumulate up to 55 gallons of hazardous waste or one quart of acutely hazardous waste in a satellite area, (Also, under the 40 CFR 262.34 requirements, a generator can store hazardous waste for up to 90 days without a permit).

Disposal of certain restricted wastes such as those wastes listed in 40 CFR 268.1(c) is allowed. For example, small-quantity generators generating less than 100 kilogram of non acute hazardous waste or less than 1 kilogram of acute hazardous waste per month are exempt from LDRs. Certain exempt wastes may be land disposed under certain conditions and are exempt from storage restrictions as long as they remain exempt.

(For further discussion see 54 FR 36968, September 6, 1989 and 55 FR 22660, June 1, 1990.)

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How do state laws apply to LDRs?

Like other RCRA requirements related to mixed-waste, the LDRs will apply only in states in which EPA administers the RCRA program (unauthorized states) or in states that have adopted mixed-waste requirements as part of their authorized state programs. In remaining the states, LDRs will apply to mixed-wastes only when the state obtains authorization to regulate them.

States may implement their own disposal restrictions if they are more stringent or broader in scope than the federal restrictions (RCRA section 3009 and 40 CFR 271.1(I)). In these cases, state laws supersede federal laws.

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