In-Lab Disposal Methods

In-Lab Disposal Options

This section contains procedures specific to laboratory waste handled by laboratory personnel familiar with chemical operations. IUEHS collects a wide range of chemical waste from laboratories, but alternative disposal options are acceptable for some of these wastes. Refer to Attachment A of this Guide for a list of disposal options for common laboratory chemicals. Contact IUEHS for your respective campus for questions regarding any chemical not found in Attachment A. There are three basic routes of disposal of laboratory chemical waste:

  • Sanitary sewer or trash disposal of non-hazardous materials;
  • Acid-base neutralization, followed by sewer disposal. Note:Any other type of treatment must be part of an experimental procedure to be considered legal; and
  • IUEHS management for offsite treatment or recycling - Campus-specific waste management procedures are found in Sections 5-7. Those sections outline how to correctly identify, package, and segregate waste; waste storage requirements; and IUEHS waste collection for both laboratory and non-laboratory operations.

Acid-Base Neutralization

The wastes designated in Attachment A: Disposal Options for Specific Chemicals for acid-base neutralization may be handled in-lab using the procedures below. Please note the following limitations:

  • Strong, concentrated acids or bases are limited to quantities of 25 milliliters (ml) or less, and must be diluted 10 to 1 before being neutralized and discharged to the sewer. Quantities that exceed 25 ml must be managed by IUEHS.
  • Oxidizing acids including chromic, perchloric and nitric acids in any amount are to be managed by IUEHS.
  • Acids or bases that contain heavy metals must be managed by IUEHS.

Neutralization Procedures

Caution: vapors and heat are generated during neutralization. Note that acid-base neutralization is not required for disposal with IUEHS. When in doubt, or if neutralization is not feasible, any materials can be placed in disposable containers for IUEHS management.

  • Perform all steps slowly and keep containers cool while neutralizing.
  • Acid neutralization: Make a basic solution using a large volume of cold water and an appropriate inorganic base. Stir the solution while slowly adding diluted acid.
  • Base neutralization: First add the base to a large vessel containing water. Slowly add an appropriate inorganic acid.
  • Allow the contents to react for 15 minutes to dissipate any heat before testing the pH. The container should not be hot, and the contents should not be smoking. If the container is still hot after 15 minutes, allow the reaction to continue until the heat has dissipated before continuing to the next step.
  • Test the neutralized solution to confirm a pH between 5 and 9, and flush to the sewer with at least 20 parts water.