The intent of the US EPA's Resource Conservation and Recovery Act (RCRA) hazardous waste regulations is to create safe standards for US facilities to generate, manage, store, transport, treat, and dispose of hazardous wastes.
RCRA lays out a "cradle-to-grave" management system for hazardous waste: The "cradle" is the waste's point of generation, and the "grave" is the final resting place for the waste, often a landfill. When exposed to the environment, containers holding disposed-of hazardous waste may corrode or fail, allowing waste to leach out into the ground.
To help make sure waste will have minimal impact on the environment and public health, EPA requires hazardous waste generators to treat hazardous waste before disposal until the presence of its hazardous constituents falls below a given threshold. No hazardous waste can be disposed of until it has been treated to these standards, known as Land Disposal Restrictions, or LDRs.
40 CFR 268 states that the initial generator of a waste is responsible for ensuring the waste has met LDR treatment standards prior to disposal. While generators often rely on the treatment, storage, and disposal facilitates (TSDFs) to run tests on the waste and make treatment determinations, it is ultimately the generator's responsibility to verify and certify this information. RCRA Hazardous Waste LDR Treatment Standards
To determine the specific LDR treatment standards for a hazardous waste, the generator must consider the original properties of the waste. When a hazardous waste is first generated, the generator assigns appropriate waste codes dictated by the RCRA rules. These codes provide information about the constituents in the waste and the waste's hazardous characteristics.
Have questions about assigning RCRA waste codes? Read more here: Simplifying Your Approach to Waste ID
In short, there are two main types of waste codes: "listed" codes and "characteristic" codes.
Listed codes come directly from lists found in the RCRA regulations, which break hazardous wastes up by industry type, source, and type of waste. Characteristic codes designate one of four specific hazardous characteristics: ignitability, corrosivity, reactivity, and toxicity.
In some cases, two RCRA waste codes may represent the same constituent or hazard, which makes designating the waste for treatment more complex.
For example, if a generator ships a container of spent benzene for treatment, the benzene is marked with a listed waste code, F005 for benzene, and three characteristic codes: D001 for ignitability, D006 for toxicity of cadmium, and D018 for toxicity of benzene. Since the hazards of benzene cause multiple waste codes to be assigned to the material, treating the benzene to an acceptable level will also mitigate the hazards caused by benzene's ignitable and toxic characteristics. Therefore, not all of the waste codes above are "significant waste codes" that require treatment. The EPA has methodology for determining which waste codes are "significant" and which are not. RCRA Rules for Determining Significant Waste Codes
If a hazardous waste carries only listed waste codes (F, K, U, or P codes) or only characteristic waste codes (D codes), all the waste codes are "significant" and all treatment standards apply.
In our spent benzene example above, the waste carries both listed and characteristic codes. The listed waste codes always take precedence, so you would start with the standards for F005 wastes. Because benzene is the root cause of the waste's ignitability (D001) and benzene toxicity (D018), the D001 and D018 codes are not significant. Treating for benzene will mitigate these two benzene-based characteristics. The D006 code, however, represents cadmium toxicity. Because the cadmium toxicity is a unique hazard (not related to benzene), the cadmium must also be treated to acceptable levels, making the D006 code significant. So, for the waste in our example, two waste codes are "significant" for treatment purposes: F005 and D006. Treating Underlying Hazardous Constituents (UHCs) in Your Waste
In certain situations under RCRA, hazardous wastes require additional treatment; wastes sometimes contain constituents that, while hazardous, are not assigned waste codes. EPA calls these constituents Underlying Hazardous Constituents, or UHCs, and the rules for them are found at 40 CFR 268.48. The treatment standards for some D codes indicate that in addition to the treatment standard listed, you must also follow "and meet the § 268.48 standards." These are the universal treatment standards.
If your hazardous waste contains a constituent listed in 40 CFR 268.48 that has not already been treated for under a waste code, the waste must also be treated to the listed standard.
For example: What if the spent benzene from our earlier example had also been contaminated with 4 mg/L TCLP of lead? While this amount of lead would not require its own D code, the D006 code for cadmium refers generators to 40 CFR 268.48, meaning the waste must be treated to the universal standard for lead, 0.75 mg/L TCLP.
Learn more about identifying UHCs in your waste here: Identifying Underlying Hazardous Constituents
As you can see, there are many steps required to determine what treatment must be done to a waste prior to disposal. There are also many variations on how the rules can apply, specific exemptions, and unique documentation requirements. Demystify the LDR Requirements
At the Land Disposal Restrictions Webinar
, hazardous waste professionals develop a clear, step-by-step approach to meeting EPA's treatment and disposal requirements. From using the treatment standards table at 40 CFR 268.40 to determining significant waste codes and identifying UHCs, you'll build confidence and be ready to keep your site in compliance. Plus, learn how to select the right TSDF for your site and keep treatment costs under control. Can't attend live? Learn anytime, anywhere with the interactive Land Disposal Restrictions online course