Solvent Stills and Hazardous Waste Counting
This guidance document is advisory in nature but is binding on an agency until amended by such agency. A guidance document does not include internal procedural documents that only affect the internal operations of the agency and does not impose additional requirements or penalties on regulated parties or include confidential information or rules and regulations made in accordance with the Administrative Procedure Act. If you believe that this guidance document imposes additional requirements or penalties on regulated parties, you may request a review of the document.

Form #: 02-120 Guidance Documents Revised: 11/30/22

Title 128 – Nebraska Hazardous Waste Regulations are designed to regulate hazardous waste generators. The regulations that apply to spent solvents and how spent solvent counts towards each calendar month’s hazardous waste generation are not very clear for users of solvent stills. This document is intended as a guide on hazardous waste rules as they apply for solvent still users.

  • Once a solvent still is operational, the user can get a “break” on counting hazardous waste generation. Title 128, Chapter 9, §003.03 and Chapter 10, §001.04C states the “generator need not include: …spent materials that are generated, reclaimed, and subsequently reused on-site, so long as the spent materials have been counted once.” Translation: This means that once a batch of spent solvent has been recycled once in a solvent still, all following spent solvent recycled from that batch and reused on-site does not count as hazardous waste generated. This counting rule only applies in a given month. Previously distilled solvent that becomes spent in a following month becomes countable hazardous waste once again and the cycle continues month by month.

  • Even though previously distilled spent solvent does not need to be counted as hazardous waste in the current calendar month, previously distilled spent solvent that is accumulated must be managed as hazardous waste. For example, small and large quantity generators of hazardous waste must accumulate hazardous waste in labeled and closed containers.

  • Facilities should maintain a solvent still log or record that documents the date of each spent solvent batch, the amount of spent solvent being distilled in the batch, and if the batch being distilled is newly spent, or previously distilled the current month. Only spent solvent previously distilled the current month is not included in the quantity of hazardous waste generated. The still log or record should also include the weight of still bottoms produced for each distillation run.
  • If a batch of spent solvent consists of a mix of previously distilled solvent from the current month and newly added solvent used in the current month, use the appropriate volumes for determining the weight of hazardous waste generated in the current month. For example, if you distill a 10-gallon batch of used solvent (at 8 pounds per gallon) but 1.5 gallons is newly added solvent, then 12 pounds (1.5 gallons x 8 pounds/gallon) of the mix is counted towards the current month’s hazardous waste generation.

  • New solvent that becomes spent in a month that was used to replace spent solvent lost to drag-out, evaporation, spills, etc. counts as hazardous waste generated. Facilities can maintain a log or record that tracks the amount of new (not yet recycled) solvent that is spent each month. This data can be used to accurately document hazardous waste generation.

  • Using the Chapter 9, §003.03 or Chapter 10, §001.04B on-site reclamation paragraph, proper use of a solvent recovery still very often enables a facility to become a conditionally exempt small quantity generator (CESQG) of hazardous waste subject to the reduced requirements of Title 128, Chapter 8.
  • The still bottoms produced during the distillation/reclamation process of a F-listed waste will be F-listed waste in accordance with the “derived from rule” and needs to be managed as a hazardous waste (Title 128, Chapter 2, §006.02). Per Title 128, Chapter 9, §003.02 or Chapter 10, §001.04B, the still bottoms or “cake” from the process do not need to be counted in determining the quantity of hazardous waste generated so long as the original hazardous waste that is treated was counted once. This means the still bottoms or “cake” from the first pass through the still of batch “A” of solvent is not counted towards monthly generation (because its weight was already counted in the weight of the undistilled solvent). This also means the still bottoms or “cake” from the second and subsequent passes of batch “A” must be counted towards monthly hazardous waste generation (because that weight is not being counted in the solvent weight). This counting rule only applies in a given calendar month.

  • If a facility becomes a CESQG, it may send up to 43 pounds per day of its hazardous waste still bottoms to a permitted, licensed municipal solid waste landfill (Title 128, Chapter 8, §006.03). Contact your landfill prior to disposal; landfills are allowed to be more restrictive. The still bottoms must be able to pass the “paint filter” test – no free liquids.

  • Remember to consider every calendar month a new counting event. Any previously distilled spent solvent left over from a previous month is considered never distilled for hazardous waste counting purposes at the start of a month.


Useful Websites:


  • NDEE Hazardous Waste Compliance Assistance (402) 471-8308
  • NDEE Waste Management Section (402) 471-4210
  • NDEE Toll Free Number (877) 253-2603

NDEE Publications*:

  • Title 128 – Nebraska Hazardous Waste Regulations
    Titles are available on the NDEE Home Page under “Laws/Regs & EQC”, “Rules & Regulations”

  • Environmental Fact Sheet – Comparison of Hazardous Waste Generator Requirements (00-055)
  • Environmental Guidance Document – Chemical Waste Disposal Options for Small Businesses (05-184)
  • Environmental Guidance Document – Waste Determination (05-176)
  • NDEE Report – Waste Service Providers Directory (WAS-025)
    Guidance is available on the NDEE Home Page under “Publications & Forms”.

Produced by: Nebraska Department of Environment and Energy, P.O. Box 98922, Lincoln, NE 68509-8922; phone (402) 471-2186. To view this, and other information related to our agency, visit our web site at