SOM030
It is illegal and unethical to dispose of anything in an inappropriate or unsafe manner. This includes the cleaner emptying the waste bin, the bin men emptying the skip, the environment from many sources of waste.
This document outlines general and specific guidelines on preferred methods to dispose of materials. If it is unclear how to dispose of your material or it is not covered by this document contact your Supervisor and the Safety Advisor.
Disposal Guidelines
Description ofWaste / Includes / Does not include / Disposal Route
1 / Paper / Office paper / Card board / Campus Waste Paper bins
2 / Cardboard / Card board / Campus Waste Card board bins
3 / Plastic / Fizzy drink bottles, milk bottles / Campus Waste Plastic bins
4 / Glass (clean) / General glass / Pyrex or silica glass or contaminated glass / Campus Waste Glass bins
5 / Batteries / General domestic batteries / Car or large batteries / Campus Waste battery buckets
6 / Organic solvents / Various / various / See Organic solvent disposal
7 / Chemicals / various / various / See Chemical disposal
8 / Asbestos / All asbestos / Safety advisor must be informed. Double bagged in specific bags and disposed via disposal company
9 / Toxic Substances / Mercury / Bottled and disposed via waste disposal company
Other / Metal, general rubbish, wood, rubble / Any of above / Use skip, some sites have separate metal disposal
General Hazardous Waste guidelines:
All laboratory waste containers must be:
· In good condition with no leaks or cracks, and suitable for contained waste, e.g. strong acids may not be stored in plastic bottles and hydrofluoric acid may not be stored in glass bottles. Empty containers of which the product was originally received are best reused as waste containers.
· Kept closed except when adding waste,
· Separated from other incompatible wastes,
· If necessary, stored in clean and compatible secondary containment,
· Affixed with a fully completed hazardous waste label, with records indicating contents, approx concentrations, date and name,
· Funnels left in bottle mouth is not acceptable,
· Do not over fill liquid containers; leave enough air space for expansion.
Spill kits are available in all chemical areas also use appropriate personal protective equipment. Report all major spills, i.e. if hazardous or large amount on the Universities Accident (if an injury) or Incident forms.
Organic Solvent Disposal:
1. Non - Chlorinated Organic SolventsAcetone / Ethanol / Amassed in lab in properly labelled container, transferred to outside chemical store for disposal by waste disposal company, recording what the waste is, who is disposing it and when.
A vented cap should be used if there is any possibility of the waste generating / liberating gas or vapours. When a ventilated cap is used, the waste should be kept in a well ventilated area.
Methanol / Petroleum Ether
Butanol / Hexane
Isopropanol / Heptane
Meths (IMS) / Xylene
Tetrahydrofuran (THF) / Butanone (MEK)
Dimethyl Acetamide (DMAc) / Cyclohexane
Toluene / DimethylFormamide (DMF)
Ether / 1,4 Dioxan
2. Halogenated Organic Solvents
Trichloroethylene / Carbon TetraChloride / Amassed in lab in properly labelled container, transferred to outside chemical store for disposal by waste disposal company.
Chlorobenzene
Dichloromethane
Chloroform
3. Nitrogenised Organic Solvents
Pyridine / Amassed in lab in properly labelled container, transferred to outside chemical store for disposal by waste disposal company.
Chemical Disposal:
1. Acids
a. Hydrofluoric Acid – see SOM017 – Hydrofluoric Acid Solutions
2. Bases
3. Heavy Metal Salts - e.g. nickel chloride, lead chloride, platinum chloride etc.
4. Amines
5. Oxidisers
6. Extremely Toxic compounds
a. Mercury – mercury spills can be avoided by using supplies and equipment that do not contain mercury. However, most mercury spills do not pose a high risk.
The initial response to a spill of elemental mercury should be to isolate the spill area and begin the clean up procedure. Those doing the clean up should wear protective gloves. The cleanup should begin with collecting the droplets. The large droplets can be consolidated by using a scraper or a piece of cardboard, and the pool of mercury removed with a pump or other appropriate equipment. For cleaning up small mercury droplets, use wet towelling, which consolidates the small droplets to larger pieces, or picked up with a piece of adhesive tape.
Commercial mercury spill sponges and spill control kits are available. The common practice of using sulphur should be discontinued because the practice is ineffective and the resulting waste creates a disposal problem. The mercury should be placed in a thick-wall high density polyethylene bottle and transferred to a central depository for reclamation. After a mercury spill the exposed work surface and floors should be decontaminated by using an appropriate decontamination kit.
b. Ethidium Bromide (Gels and solutions) – Ethidium Bromide is commonly used in molecular biology laboratories. While it is not recognised as hazardous waste, the mutagenic properties of this substance may present a hazard if it poured down the drain untreated or placed in the solid waste bins. Gloves, test tubes, paper towels, etc., that are grossly contaminated with ethidium bromide should be placed in the medical waste for incineration.
i. Gels – Trace amounts of ethidium bromide in gels should not pose a hazard. Higher concentrations, e.g., when the colour of the gel is dark pink or red, should not be placed in laboratory waste bins. It is recommended that:- Less than 0.1% ethidium bromide: place in laboratory waste, more than or equal to 0.1%: place in biohazard waste for incineration.
ii. Solutions – Aqueous solutions containing <10µg/ml ethidium bromide can be released to the drain. Aqueous solutions containing >10µg/ml ethidium bromide should be filtered or deactivated using one of the methods described below. Charcoal filtration is strongly recommended over chemical deactivation. Solutions containing heavy metals, organics, cyanides or sulfides should be disposed as hazardous waste.
1. Charcoal Filtration – Filtering the aqueous ethidium bromide waste solutions, free of other contaminants, through a bed of activated charcoal is a relatively simple and effective method for removal of ethidium bromide. The filtrate may be poured down the drain with copious amounts of water. The charcoal filter can be placed in a sealed bag and placed in bio-hazardous waste for incineration. There is also a ‘Green bag’ method which also uses a charcoal absorbent.
2. Chemical method – There are several chemical methods for neutralisation of ethidium bromide – see supervisor and local rules for guidance.
Disposal of Reaction Solutions
Read these instructions before proceeding
All described procedures should be carried out in a fume hood. Use additional shielding as required. Suitable and proper Personal Protective Equipment, PPE (lab coat, safety glasses and appropriate gloves) must be worn.
Please consult primary literature and your supervisor for details on protocols for the proper handling of waste not listed here.
DO NOT pour ‘reaction’ solutions down the drain.
These solutions should be disposed of carefully.
Prior to disposal all solutions need to be checked for oxidisers and pH.
If the presence of oxidisers is suspected then take a small sample and dilute, say 4 times with water and make acidic, then check with starch iodide [white if neutral and blue to violet if present].
Acids or bases should be checked for with pH paper before disposal [pH7].
To do this take a sample of the solution and dilute it [e.g. 250 ml to 5 litre of water]. If the acid or base is highly concentrated, it is prudent to first dilute it with cold water (adding the acid or base to the water) to a concentration below 10%. Then neutralise with either sodium or magnesium hydroxide or sulphuric or hydrochloric acid, respectively can be used.
If oxidisers are present, then the solution needs to be neutralised [reduced], this is carried out by adding ferrous sulphate, whilst the solution is in the acidic state, until the presence of oxidisers can no longer be detected.
If your solution is not acidic then it needs to be acidified with a mineral acid e.g. HCl, H2SO4.
If you are removing or neutralising a solution containing ‘heavy metals’, e.g. chromium, then the solution needs to be acidic and to contain iron, e.g. iron shot, iron filings etc.
The solution is then neutralised using sodium carbonate to pH7. [it is necessary to use calcium chloride when fluorides are present in the solution, e.g. 250 gm for 1 litre of 5% HF solution].
When neutral from an oxidising point of view and neutral from a pH point of view [pH7] the supernatant solution is ‘safe’ to discard down the sink with copious amounts of water, and any non-hazardous waste solids are to be bagged and discarded.