Every opened vial of bacteriostatic water ends its life with liquid still in it, because the 28-day discard rule does not wait for the vial to be empty. Disposal is simple, but a few points are worth getting right. Local and institutional regulations always take precedence over the general guidance here.
What is being disposed of
Residual bacteriostatic water is a dilute aqueous solution of benzyl alcohol, 9 mg per mL, with no other solutes. Benzyl alcohol is readily biodegradable and is not classified as an environmental hazard at this concentration, but it is an organic chemical and some jurisdictions and institutions regulate any chemical drain disposal. The vial itself is glass or polyolefin with a rubber stopper and an aluminum crimp. Withdrawal devices used with the vial are sharps.
Residual liquid
- Check the institutional rule first. Many facilities permit drain disposal of small volumes of dilute, water-miscible, non-hazardous solutions with copious running water; others route all chemical waste to a collection stream. Follow the local rule, not this page.
- Where drain disposal is permitted, the residual from a 30 mL vial is well within typical small-volume allowances. Flush with plenty of water.
- Where it is not, add the residual to the aqueous organic waste container, labeled with its contents ("water, benzyl alcohol 0.9%").
- Never pour residual from one vial into another vial for reuse, and never decant into unlabeled containers.
Vials
- Glass vials go to the laboratory glass waste stream (broken-glass box or equivalent), not general refuse, whether empty or containing residual after the liquid is handled as above. Leave the stopper and crimp in place; removing crimps is a cut hazard with no benefit.
- Plastic vials go to the laboratory plastics or general laboratory waste stream per local rules. They are not usually recyclable through municipal streams because of the elastomer and aluminum components.
- Deface the label or mark the vial as discarded if there is any chance a partly full vial could be mistaken for stock.
Withdrawal devices
Needles and syringes used to withdraw from the vial go to the sharps container immediately after use, never recapped, never left in the stopper. This is standard laboratory sharps practice and applies regardless of the vial's contents.
Unopened expired vials
Sealed vials past their expiration date are disposed of the same way as opened ones. Some institutions require expired sealed product to be logged as chemical waste with the quantity; check. Do not return expired product to a supplier unless asked to.
Quarantined or defective lots
Vials set aside because of a suspected defect (cloudiness in a sealed vial, seal failure, lot mismatch) should be retained, not disposed of, until the supplier has been notified and has responded. The supplier may ask for photographs or for the vials to be returned for investigation. See lot traceability.
Records
Note the discard of a lot in the inventory log when the last vial is gone, so that quantities reconcile. Where chemical waste is logged, record the volume of residual liquid disposed of by each route. The full procedure fits into the SOP template.
Reducing what is discarded
The volume thrown away is almost entirely a function of vial size. A bench that discards two-thirds of every 30 mL vial should be using 10 mL vials. The arithmetic is in choosing a vial size and the calculators.
All BAC Water Supply products are supplied for laboratory research use only and are not for human or veterinary use.