RCRA—Waste Treatment/Minimization

There are many ways to use RCRA reliefs to cut costs at your facility. You can reuse spent materials, turn your waste into someone else's product; recycle scrap metals, circuit boards, ethanol, cathode ray tubes, used oil, batteries, and other universal wastes; reclaim value from sludges and by-products; neutralize corrosive wastes; install a closed-loop reclamation system; or decharacterize or solidify wastes in process-units. Of these options, one of the most widely used is elementary neutralization of corrosive waste.

The Advantages of Elementary Neutralization

One common, and bulky, type of hazardous waste generated in many industries is liquid solutions that exhibit the hazardous characteristic of corrosivity. These corrosives may be by-products of chemical reactions, spent catalysts, sludges from wastewater treatment systems, or simply industrial cleansers.


Under certain conditions, you can treat this type of hazardous waste yourself, without a permit. This process is called "elementary neutralization." [40 CFR 260.10] Taking care of your own hazardous waste has many advantages:

  • Reduce your generator status. Wastewaters are measured in gallons, but generator status is measured in pounds. Every gallon of corrosive wastewater you can exclude from regulation as hazardous waste equals about 8 pounds you can subtract from your monthly totals. Since wastewaters are typically generated in large amounts, on-site treatment can leverage great waste minimization gains.
  • Reduce your freight costs. If you're currently shipping large volumes of corrosive wastewater to an off-site treatment facility, you're paying freight costs to transport the waste AND treatment costs to neutralize it. By treating the waste on site, you can save on shipping costs.
  • Neutralization is cheap. After any on-site storage, as well as recordkeeping and other administrative expenses (which you're already doing for the waste), the only additional expense for an elementary neutralization operation is a small amount of common industrial caustic.


What Kinds of Wastes Qualify?

Elementary neutralization can be applied to hazardous wastes that 1) exhibit the hazardous waste characteristic of corrosivity defined at 40 CFR 261.22, 2) do not exhibit any other characteristics, and 3) are not listed as hazardous waste at 40 CFR 261, Subpart D. While this description is very specific, this type of waste is generated by many kinds of facilities, typically in large amounts.

How Does the Treatment Work?

  • Accumulate the waste in a tank, tank system, or container.
    • Transport vehicles and vessels are also authorized, but their use can create complications.
    • As long as you "immediately manage" the waste in an elementary neutralization unit, you don't have to count it towards your generator status. [40 CFR 261.5(c)(2)]
    • Depending on your setup, you may even be able to skip this step (treatment in "process unit"). [40 CFR 261.4(c)]
  • Add base/acid to the waste to raise/lower the pH above 2 or below 12.5 to reach a neutral pH.
  • Dispose of the decharacterized water.

What Else Do I Have to Do?

  • Check the laws, regulations, and policies of the hazardous waste management authorities in your state. Not every jurisdiction authorizes this activity, and some that do will impose additional restrictions or requirements.
  • If you intend on discharging the neutralized wastewater to a municipal sewer, you must get permission from the waterworks.
  • If you intend on discharging the neutralized wastewater to surface or underground waters, you must have an NPDES permit from the U.S. EPA.
  • Keep records of the amount and type of waste you generated and treated to rebut any presumptions of speculative accumulation or sham recycling.
  • File a One-Time Notice in your facility's Land Disposal Restrictions records. [40 CFR 268.7(a)(7)]


Operating an elementary neutralization unit (ENU) isn't easy, and it isn't the right solution for everyone. But if your facility generates large quantities of corrosive wastewaters, then setting up an ENU can minimize your waste generation, cutting your shipping costs and treatment fees, and possibly reduce your generator status