What chemicals CAN be disposed of down the sink?

Aqueous chemical solutions can be disposed of down the sink provided:

• Chemicals are dilute and below relevant hazardous waste threshold level(s).
• They are not on the Prescribed Substances list of chemicals that should never be disposed of down the sink through the sewerage system.
• They are not excluded on the permit for the specific campus. 

It is recognised that research labs will generate small volumes (a few hundred millilitres) of relatively innocuous chemical solutions that would no longer be classed as hazardous following moderate dilution.  As such, it is acceptable for solutions of small volumes (typically < 500 ml) of non-toxic water soluble chemicals to be carefully washed down the sink with plenty of running water.

The assessment of what is a 'small amount' relies on professional judgement, bearing in mind the concentration levels at which the substance(s) are toxic or otherwise harmful.

Larger quantities or highly concentrated chemical substances must not be put down the drain and must be disposed of via QMUL hazardous waste disposal route. 

Examples of low hazard, water soluble waste that CAN be put down the sink include:

• Diluted acids, alkalis and alcohols
• Harmless inorganic salts (including drying agents  such as CaCl2, MgSO4, Na2SO4, P2O5)
• Alcohols containing salts (e.g. from destroying sodium)
• All disinfectant solutions used to inactivate Hazard Groups 1 and 2 biological agents
• Hypochlorite solutions (e.g. from destroying cyanides, phosphines)

If you are in any doubt whether a solution can be put down the sink contact your Faculty Health and Safety Manager/Adviser http://www.hsd.qmul.ac.uk/contact-us/

What chemicals MUST NOT be disposed of down the sink?

No waste substances should be put down sinks that could ultimately harm:

• The environment.
• The sewerage system.
• The health and safety of the public or have the potential to interact with other substances to cause such effects.

However, it is acceptable for waste solutions from experiments containing trace / low levels of hazardous organic or water miscible chemicals to be disposed of via the sinks, but must be flushed with plenty of water. 

Examples of wastes that SHOULD NEVER be discharged to drain via sinks:

• Persistent chemicals  such as heavy metals and various organic compounds
• Water immiscible organic liquids such as petroleum hydrocarbons and chlorinated compounds
• Compounds which produce toxic vapours, such as cyanide, ammonia, formaldehyde and glutaraldehyde
• Strongly acidic or alkaline wastes (pH < 6 or pH > 11)
• Highly reactive chemicals or flammable wastes
• Prescribed substances as per Trade Effluent Regulations 1989

If you are in any doubt whether a solution should not be put down the sink contact your Faculty Health and Safety Manager/Adviser http://www.hsd.qmul.ac.uk/contact-us/ .