Bench top treatment refers to a process used by research labs to perform authorized treatment of wastes per California regulations1. Bench top treatment methods are bounded by practices cited in “Prudent Practices in the Laboratory – Handling and Disposal of Chemicals” published by the National Research Council. Often bench top treatment is used to neutralize corrosive mixed wastes to avoid treatment charges. However, any experimental reaction mixture that contains nitric acid (HNO3) or any surplus nitric acid aqueous solution must either be carefully diluted to reduce the concentration of the nitric acid or neutralized. Either process must be authorized by an approved bench top treatment procedure.
All nitric acid solutions regardless of concentration that contain organic matter or metallic impurities must be neutralized. Nitric acid solutions >5% by weight, 0.8M or pH <1 with no organic matter or metallic impurities may either be diluted and/or neutralized.
Neutralization and/or dilution will treat these wastes for proper, safe storage and will avoid the inadvertent mixing with incompatible materials creating a safety hazard to those in the lab.
There are several regulatory requirements that must be met before a bench top treatment authorization can be approved. Your Generator Assistant will work with you to assure all requirements are met and will present the information to Waste Management for approval. The requirements include:
- A written neutralization procedure including:
- Description of the process generating the waste and quantity2 to be treated,
- Treatment location (as close as practical to the generating location),
- Treatment process and materials,
- A list of personnel authorized to perform the treatment
- A treatment log showing the dates of treatment, quantity, etc.
- Knowledge of the waste. If the treated waste will be sent to the Waste Management Group for disposal, generator process knowledge may be used. If the treated waste is to be discharged to the sanitary sewer, the waste generating process must not involve the presence of metals or organics above permitted levels. Certified laboratory analysis of the waste for sanitary sewer discharge is required (your Generator Assistant will assist you in getting this analysis completed).
- Written approval for discharge signed by Robert Fox or another ESG designee for waste that can be discharged to the sanitary sewer after treatment. If the waste is radioactive and you believe it appropriate for sewer discharge, limited to isotopes with <90 day half-life, additional approval must be given by your Health Physicist.
- The evidence that the appropriate procedural training has been completed by each authorized person. (a training log showing a description of topics covered). The training record must be maintained for three years.
- A treatment log must be maintained for treated waste indicating date and amount of waste treated and the person that performed the treatment.
Note: Depending on the specific circumstances, waste may be required to be neutralized immediately after use (aqua regia is an example). The treatment procedure will specify the appropriate treatment time. In all cases, the waste must be treated within 10 days from the first addition of waste to the waste container (SAA start date).