Elementary Neutralization

EPA Definition: Elementary Neutralization Unit

Elementary neutralization unit means a device which: 
(a) Is used for neutralizing wastes only because they exhibit the corrosivity characteristic defined in § 261.22 of this chapter, or are listed in subpart D of part 261 of this chapter only for this reason; and 
(b) Meets the definition of tank, tank system, container, transport vehicle, or vessel in § 260.10 of this chapter. 

EPA Guidance Documents
    RCRA Online GuidanceSumps, as defined in 260.10, are tanks. A neutralization sump and ancillary equipment                     handling corrosive-only wastewater qualify for the elementary neutralization unit (ENU) exemption

Elementary Neutralization: Treatment Without a Permit

Link to Original Reference: Originally Posted in the Public Domain by Lion Technology Inc. August 28,2012 by James Griffin

Treating your hazardous waste without a permit?! Is that really possible? Yes! Yes, it is. While the EPA generally prohibits you from treating hazardous waste without a permit, there are exceptions. Under certain conditions you can neutralize your corrosive hazardous waste and pipe it out as sewage rather than containerize it and freight it to an expensive treatment facility. [See 40 CFR 270.1(c)(2)(v).]
How Do I Qualify?
Hazardous wastes eligible for this exclusion can be unused products, off-spec mixes, residue from spills, cleanup or storage, or any byproduct or cogenerated materials, as long as they meet two conditions:
  1. The waste is hazardous ONLY because of the corrosivity characteristic (D002).
  2. The waste is neutralized in a tank, tank system, container, transport vehicle, or vessel as defined in 40 CFR 260.10.
What Are The Advantages?
Treating hazardous waste in an elementary neutralization unit (ENU) does NOT require a RCRA treatment permit. [40 CFR 270.2(c)(2)(v)] This is the primary advantage. Although elementary neutralization systems are usually tanks or containers, ,these units are not subject to the waste storage management standards codified in 40 CFR Parts 264 and 265. [40 CFR 264.1(c)(10), 265.1(c)(10)]
If you manage to store the hazardous waste in the elementary neutralization unit IMMEDIATELY upon generation, you do not need to count it when counting hazardous waste towards your generator status, as it is “not subject to substantive regulation.” [40 CFR 261.5(c)(2), 262.10(b)] This reduction in your facility’s hazardous waste total may class down your generator status and provide flexibility for your other hazardous wastes. Keep in mind that this hazardous waste must still be recorded and included on your Biennial Report, should you be required to file one.
What Rules Do I Still Have to Follow?
Any wastes generated from the neutralization process (precipitated solids, etc.) must be managed appropriately. If these residues exhibit any characteristic, then they are hazardous waste and must be managed accordingly. Otherwise, comply with state/local regulations for industrial wastes. [40 CFR 261.3(d)(1), 261.3(g)(2)(ii)]
Since the waste was hazardous at the initial point of generation, the land disposal restrictions (LDRs) may still apply even after neutralization. The presence of underlying hazardous constituents (UHCs) in excess of the LDR threshold may require additional treatment, either on site or at an off-site facility. Either way, there are significant recordkeeping requirements. [40 CFR 268.7, 268.9]
What Do I Do With My ENU Waste?
Once you have neutralized the waste, extracted the residuals, and treated for UHCs, you still have a large quantity of wastewater and need to dispose of it somehow. In many areas, you may be able to negotiate with the waterworks and simply pour the neutralized wastewater into a sewer. In other areas, you may have to get a wastewater discharge permit or arrange for the wastewater to be trucked or piped away.
Characterizing hazardous wasteElementary Neutralization: A RCRA Exclusion
The ENU exclusion is distinct from other relief provided for hazardous waste treatment, such as EPA’s longstanding interpretation that a hazardous waste generator may treat-while-accumulating hazardous waste in units managed in accordance with 40 CFR 262.34.
As always, state authorities may have more specific or limited allowances for elementary neutralization. So, it is important to see how your state views elementary neutralization prior to changing your current practices.
Are you already using elementary neutralization? Have any tips for those who haven’t tried it? Share your comments below!
Capitalize on other RCRA exclusions and get tips on more best practices at Lion’s Advanced Hazardous Waste Management Public Workshop. Learning to take advantage of these RCRA exceptions and exemptions is critical for compliance managers looking to reduce waste and cut costs.
Sources: [RCRA Online 13204, 13170, 12811, 11439, 13649, 13717, 13778, 14470. 40 CFR 261.5, 262.34, 270.1. 51 FR 10152-10168 March 24 1986]
Posted in: Hazardous Waste
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