28 June 2012
NOTES ON CHEMICAL WASTE MANAGEMENT IN THE TEACHING LABS
Public opinion of waste management and federal and provincial legislation are constantly changing
as environmental awareness grows. Unfortunately, the public's perception of how we, as chemists,
deal with our chemical waste does not seem to change as fast. The Department, and of course the
University, revise our practices frequently. The purpose of these notes is to bring you up to date with
the current guidelines.
Laboratory waste is divided into five categories:
a) Landfill Waste. This would typically be paper towels used for hand drying or wiping up
minor spills (dry off solvents in the hood first), non-recyclable paper, bagged loose powders
such as column packing or vermiculite (and other shipping material), used gloves etc. No
glass (including Pasteur pipettes) is allowed. Many used containers may be recycled once
they have been cleaned (see below). The few that cannot be recycled must be cleaned and
put in either the landfill waste or the glass waste.
b) Glass. Non-recyclable glass (essentially any glass other than clean empty bottles) should be
collected in the separate container in each lab. It must be cleaned, as it will also be taken to
the landfill.
c) Glass or Plastic Bottles and Containers. Most bottles and other containers in which liquid
or solid chemicals were obtained can be recycled, but they must first be cleaned. Drain the
residual chemicals into a suitable waste container. Bottles that have held acutely hazardous
or reactive waste must be rinsed with a suitable solvent. When residual volatile liquid is
present after draining, place in a fume hood to allow evaporation to dryness. Do a final rinse
with water, then take to the designated collection area. Do not dispose of pop or juice bottles
in these bins, as there are more appropriate places to recycle these on campus. Bottle caps
go into the landfill waste bin. Regarding plastics, types #1 - 7 can be recycled, as can un-
numbered bottles. Plastic types #8 or higher may be dealt with separately - contact Science
Stores for advice.
d) Organic Liquids. These are separated as to whether they contain halogens or not. Any
solvent combination including a halogenated solvent must be placed in the BLUE
halogenated waste container. Non-halogenated solvents go into the RED container. Both are
sent off the island for burning. It is important that the separation be correct, so that the
appropriate fuel proportions can be adjusted to maintain complete combustion. Some water
is an allowable component of a mixture, but obviously undesirable in large quantities.
Remember that any solute that is included will also be combusted. This is particularly
dangerous where heavy metals are concerned, as vaporised metal will spread deposits over
a large area of ground.
The small blue and red containers have two caps. The larger is intended as the pouring hole,
the smaller is an air leak. Since the typical fill-line is above the level of the air leak, make
sure that the small yellow cap is tightened as soon as an empty can is received.
e) Solid Chemicals. These will be collected by the person responsible for the laboratory. In
many cases, separation is required, but it would be inappropriate to list them all in this
document. Lead, thallium and mercury and their salts are the common items to separate. All
solids are appropriately packaged, recycled if feasible, or shipped to a commercial chemical
waste company (off the island!). So that they can be dealt with in the best fashion possible,
it is important that the containers be secure and labelled with as much information as to the
contents as possible. For example, both cations and anions must be defined, even if the list
has to have an "any of the above" category. The charges for disposal are related to the
contents and of course the most expensive ingredient sets the price. This is currently why
lead, mercury and thallium are separated. Remember that recycling is a much cheaper
alternative in the long run. It is cheaper to send larger and fuller containers, since volume is
a component of price (the containers are shipped in drums).
f) Waste Solutions. Any solutions generated in the lab should ideally be dealt with by the user.
To some extent, this is not practical in a teaching lab environment, and so there are
containers in which to collect these solutions. However, you will appreciate that huge
volumes can quickly make this an unworkable situation. Each student must reduce the
volume of waste generated by either precipitation of the metal, extraction or concentrating
the volume of solution on a rotovap. The collected solutions will then be further concentrated
into a viscous mass and packaged for disposal as solid waste. This task is made a lot easier
if large volumes of solutions are avoided. Each student is encouraged to process all the
chemical waste into a manageable solid form for collection.
If you are unsure what to do about disposal of a chemical, talk to a lab instructor first. DO NOT
POUR IT DOWN THE SINK! There are special methods and equipment for dealing with
chemical spills (both small and large). Again consult your instructor.
Occupational Health, Safety & Environment
Conventional Fume Hood Guidelines
1) Before using a fume hood, ensure you will be provided with an appropriate level of
protection and that the fume hood is appropriate for your work. Refer to the conditions of
use, including any restrictions, noted on the fume hood label.
a) All operations, which generate airborne
chemical contaminants, must be
performed in a fume hood.
Radioisotopes must be used in a fume
hood designated exclusively for such
use.
b) Perchloric acid must be used in a fume
hood designated exclusively for its use,
having appropriate wash down
capabilities.
c) Biohazardous materials must be used in
a certified biological safety cabinet.
2) Keep all apparatus at least 15cm (6 in) from the front face of the fume hood and
the back damper to ensure air is adequately drawn into the hood. Items stored
at the back of the fume hood and larger items should be elevated on a shelf.
3) Do not use a conventional fume hood that does not have the maximum working
sash height clearly labeled. Always keep the sash at or below this level, since
increasing the sash height reduces the air flow at the face of the hood.
4) All fume hoods should have an “Air Flow Indicator” attached to the sash. Prior
to starting work in a fume hood, check the ribbon to make sure air is flowing
into the hood (ribbon should be angled towards the hood).
5) To prevent a reduction in airflow at the face of the hood, limit the number of
individuals standing close to the fume hood and ensure that open doors and windows are not
creating a cross draft.
6) Clearly WHMIS-label all chemicals and long-term experiments including the user’s name
and date.
7) Do not use a fume hood for storing chemicals unless it has been designated for storage.
8) If a power outage occurs, fume hood function will likely be compromised. In this situation,
take precautions to ensure adequate protection. For example, prevent the build-up of vapour
and fumes by covering all chemicals, turn off natural gas, secure your experiment and close
the sash.
9) Ensure that you are aware of the nearest emergency eyewash and shower. A lab coat, gloves,
eye protection and appropriate footwear must be worn.
10) Fume hoods with an on/off switch have been labeled. Ensure the hood is turned on before
starting your work and allow time for the flow to stabilize. Before turning the hood off,
ensure that any vented chemical storage will not be affected.
11) Do not place electrical apparatus or other ignition sources inside the fume hood when
flammable liquids or gases are present in the hood.
For further information contact Occupational Health, Safety & Environment at 250-721-8971 or through their website
at http://ohs.uvic.ca/
