Waste Disposal - Disposal of Laboratory Wastes (GUIDANCE)
Appendix 1 - Waste Disposal - Flow Diagram (A copy of this diagram can be downloaded as a Microsoft Word '97 document - Waste Disposal Flow Diagram (RTF, 71 KB))
It is the clear responsibility of all research workers to ensure the safe and correct disposal of all wastes produced in the course of their work. Improper and irresponsible disposal of chemical wastes down drains, to the Local Authority, refuse collection, or into the atmosphere is forbidden by law. The Aldrich Handbook provides a useful summary of the correct disposal procedure for most chemicals. Due to new legislation, increasingly strict environmental controls and the escalating costs of disposal, it is essential that the appropriate disposal procedures given below are strictly adhered to:
- Concentrated and dilute acids and alkalis
- Harmless soluble inorganic salts (including all drying agents such as CaCl2, MgSO4, Na2SO4, P2O5)
- Alcohols containing salts (e.g. from destroying sodium)
- Hypochlorite solutions from destroying cyanides, phosphines, etc.
- Fine (tlc grade) silica and alumina
It should be noted in particular that no material on the "Red List" should ever be washed down a drain. This list is as follows:
- compounds of the following elements:- antimony, arsenic, barium, beryllium, boron, cadmium, chromium, cobalt, copper, lead, mercury, molybdenum, nickel, selenium, silver, tellurium, thallium, tin, titanium, uranium, vanadium and zinc.
- organohalogen, organophosphorus or organonitrogen pesticides, triazine herbicides, any other biocides.
- mineral oils and hydrocarbons
- poisonous organosilicon compounds, metal phosphides and phosphorus element
- fluorides and nitrites
- all organic solvents including water-miscible ones
- soluble organic waste including most organic solids
- paraffin and mineral oil (from oil baths and pumps)
All waste suitable for the Local Authority refuses collection, except recyclable paper and glass, is termed 'controlled waste'. Items in this category which includes dirty paper, plastic, rubber and wood, should generally be placed in the waste bins available in each laboratory and will be collected by the cleaners. However, each laboratory must also have a container for certain items which are not allowed to be put in the normal waste bins. In this special controlled waste container should be put:- all broken laboratory glassware, any sharp objects of metal or glass, all fine powders (preferably inside a bottle or jar) and dirty sample tubes or other items lightly contaminated with chemicals (but not any syringes or needles). Laboratory controlled waste containers must be emptied regularly and never allowed to overflow. Under no circumstances must any item of glass, sharp metal or fine powder ever be put in a normal laboratory waste bin. The tops must be removed from all bottles put out for disposal and there should be no detectable smell of chemicals from any bottle put for disposal.
This is a troublesome and expensive method of disposal and the quantity of special waste must be kept to an absolute minimum. Only the following items should be disposed of in this way:
- Schedule 1 poisons (but not cyanides) and other highly toxic chemicals
- Materials heavily contaminated with substances in (i)
- Materials contaminated with mercury
- Carcinogenic solids including asbestos.
Special waste must be collected in a separate labelled bottle or jar for disposal. On no account must different types of waste be mixed. Advice should be sought from the School Safety Co-ordinator before beginning any work which will produce waste requiring special disposal in order to ensure that :
- the waste can be disposed of
- it is collected in the most suitable form so as to minimise the cost involved
- it will be stored under suitable conditions.
The importance of handling waste for special disposal to the School Safety Co-ordinator immediately the container is full or the work is finished is emphasised. The hoarding up of hazardous waste in laboratories is strictly forbidden.
Environmental Health and Safety Services should be notified of all 'Special Waste' on the appropriate University form (see section on waste - A Microsoft Word '97 copy of the Special Waste Notification Form can be downloaded - here)
For environmental reasons the recycling of glass is encouraged, but only certain items of waste glass produced within laboratories are acceptable for recycling. Each laboratory should have a bin for recyclable glass. Only clean glass bottles such as those in which chemicals are received, and broken or waste plate glass are allowed. All broken laboratory glassware, items significantly contaminated by chemicals, sample tubes, droppers and glass wool must be disposed of as controlled waste. The recycling service will refuse to empty a recycling container if any of these prohibited items are discovered in it.
The importance of returning the specially labelled winchesters for solvents which are bought in bulk to the Store ready for direct refilling is emphasised. They must not be contaminated in any way and should not normally be washed out. Bottles containing sodium must not, under any circumstances, be returned directly to the Store. When sodium is first added to a bottle of solvent a label indicating this (available from the Store) should be attached. When the bottle is empty the sodium must be safely destroyed by adding ethanol or methylated spirit and the label removed. The bottle must then be washed out, dried and returned to the Store ready for direct refilling.
Empty winchester bottles may be re-used e.g. for the disposal of waste solvents. They must first be washed out with water if they have contained a corrosive or harmful chemical e.g. concentrated acid or ammonia.
"Sharps" contaminated with biologically hazardous materials must be collected in special containers to be sent for incineration. It is also required, at the request of Fife Council, that all syringes and needles of any type should be disposed of by the same route. No syringes or needles must ever be put in a laboratory waste bin or controlled waste container.
Note: This expensive route must not be used for Pasteur pipettes or other sharp items unless contaminated with a biohazard.