1.2 Disposal of Waste

• Waste substances can be divided into 2 types


  • Can be thrown into the sink
  • Cannot be thrown into the sink
• Waste substances that can be thrown into the sink

  • The substance with a pH value between 5 to 9
  • Solution with low concentration
  • Neutral substances
  • Weak acids
  • Weak alkalis
• Waste substances that cannot be thrown into the sink

  • Solid waste
  • The substance with a pH value less than 5 or more than 9
  • Organic solvent
  • Toxic substance
  • Heavy metal
  • Organic waste
  • Acid
  • Grease
  • Oil
  • Oil paint
  • Hydrogen peroxide
  • Microbes
  • Carcasses
  • Radioactive waste
  • Volatile substances
  • Reactive substances
• Way to dispose of toxic chemical substances

  1. Treat the waste before dispose

  2. Store in a closed container and labelled it
• Standard operating procedure (SOP) for biological waste disposal

  1. Sharp waste

  2. Non-sharp waste

  3. Carcasses, organs or tissues of organisms

  4. Bodily fluid waste
• Disposal of sharp waste

  Place the wastes in sharps waste bins before disposed
• Non-sharp waste


  • Used tissue
  • Cotton wools
  • Gloves
• Disposal of non-sharp waste

  • Place the waste into biohazard plastic bags
  • Wastes collected must be autoclaved before being disposed
• Carcasses, organs or tissues of organisms

  • Animal carcasses
  • Animal tissues
  • Plant tissues
  • Biological specimens
• Disposal of carcasses, organs or tissues of organisms

  • Wrap the wastes in tissue paper and put them into biohazard plastic bags
  • Waste collected must be autoclaved before being disposed
• Bodily fluid waste


  • Blood
  • Saliva
  • Serum
• Disposal of bodily fluid waste

  • Waste is decontaminated in autoclave machines
  • Dispose of wastes directly into the sewage system through the laboratory sinks or toilets
• 4. 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.