PRISM Micro/Nano Fabrication Laboratory

Waste Disposal Policies and Procedures

In accordance with the new EQUAD Corrosives Disposal Policy,

“Acids stronger than pH 2.0 and bases stronger than pH 12.0 may not be poured directly down the drain even if done so with copious amounts of water.  These materials should be sufficiently diluted and /or neutralized in a safe and effective manner to within the desired pH range, however neutralizing to pH 7.0 is preferred.  The resulting solution (2.0<pH<12.0) can then be poured down the drain with a moderate flow of tap water.  The SEAS stockroom has pH paper available for testing of the pH levels before disposal.”

the PRISM Micro/Nano Fabrication Lab now requires users to bottle most Acid, and Base waste, in addition to all Solvent waste.  The following chart describes the proper disposal method for the chemicals provided by the cleanroom.

Solvents and Bases to be Bottled

All Solvent Hoods contain at least one Solvent Waste Disposal Bottle with an attached funnel (and lid).  This should be used to dispose of solvents and any base with a pH greater than 12. 

Acids to be Bottled

The General Purpose Acid Hood has 4 Waste Disposal Bottles to segregate the acids according to type and reactivity. 

1. All acid solutions containing Hydrofluoric Acid (this includes any Buffered Oxide Etch) are segregated due to the cost of disposing of fluorinated chemicals. 
2. Nitric Acid and Chrome Etchant (CR-7) waste are stored in their own separate container due to reactivity. 
3. Hydrobromic Acid, Hydrochloric Acid, and Sulfuric Acid are disposed of in a third container.
4. Sulfuric Acid and Hydrogen Peroxide mixtures (Pirhana Etch), are disposed of in bottle 4.

Drain?

While some acids and bases can go down the drain, they must be diluted.  Run the cold tap water before, during, and after disposal for at least 2 minutes for a total of 6 minutes.

Hydrogen Peroxide Solutions

Hydrogen Peroxide is unstable and naturally decomposes into water and oxygen.  When different chemicals are mixed with it, this decomposition rate can accelerate.  Solutions containing Hydrogen Peroxide should never be put in a tightly closed bottle, as this will eventually lead to the bottle bursting from the resulting build up of pressure.  The remaining chemicals in the solution should determine the proper disposal method.  Pure Hydrogen Peroxide can be put down the drain.

What about….?

The disposal of any chemical not covered by this document should be discussed with Joseph Palmer, or another member of PRISM staff before the chemical is used.  If questionable waste has been generated, segregate it into its own container (properly labeled), and bring it to the attention of PRISM Staff immediately.