Disposal of Waste

1.2

Disposal of Waste

Waste substances can be divided into 2 types:

Waste Substances

Can be thrown into the sink	Cannot be thrown into the sink
The substance with a pH value between 5 to 9 Solution with low concentration	Solid waste The substance with a pH value less than 5 or more than 9 Organic solvent Toxic substance Heavy metal Organic waste
Examples: Neutral substances Weak acids Weak alkalis	Examples: Acid Grease Oil Oil paint Hydrogen peroxide Microbes Carcasses Radioactive waste Volatile substances Reactive substances

Way to dispose of toxic chemical substances

Treat the waste before dispose
Store in a closed container and labelled it

Standard operating procedure (SOP) for biological waste disposal

Example	SOP
A: Sharp waste Syringe needles Glass slides Glass pipettes	Place the wastes in sharps waste bins before disposed
B: Non-sharp waste Used tissue Cotton wools Gloves	Place the waste into biohazard plastic bags Wastes collected must be autoclaved before being disposed
C: Carcasses, organs or tissues of organisms Animal carcasses Animal tissues Plant tissues Biological specimens	Wrap the wastes in tissue paper and put them into biohazard plastic bags Waste collected must be autoclaved before being disposed
D: Bodily fluid waste Blood Saliva Serum	Waste is decontaminated in autoclave machines Dispose of wastes directly into the sewage system through the laboratory sinks or toilets

Steps to Handle Accidents in the Laboratory

Accidents of chemical substances spillage

1. Inform the teacher or laboratory assistance

2. Make the spill area a restricted area

3. Prevent the spillage from spreading using sand

4. Scoop the spilled chemical substances

5. Throw away safety

Accidents of a mercury spill

1. Inform the teacher or laboratory assistance

2. Make the spill area a restricted area

3. Pour sulphur to cover the spill

4. Inform the fire department

* Mercury is toxic it can attack the nervous system, digestive tract, reproductory system and kidneys.