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How degrading - the toilet tissue test

About this lesson

What happens when we flush something down the toilet? Where does it go in the scheme of wastewater? Follow the journey and complete the toilet tissue test to see what happens to items travelling down the toilet into the wastewater system.

Year level: 5, 6

Theme: Wastewater

Learning objectives

Students can:
  • understand what biodegradable means
  • see what happens when items are placed into the wastewater system.

Curriculum links

  • With guidance, pose questions to clarify practical problems or inform a scientific investigation, and predict what the findings of an investigation might be (ACSIS232) / (ACSIS231)
  • With guidance, plan appropriate investigation methods to answer questions or solve problems (ACSIS103) / (ACSIS086)

Things you will need

  • The Toilet Tissue Test activity sheet 
  • 2 different types of toilet paper 
  • 2 jars filled with water

Lesson description


  • Ask students to bring in two squares of toilet paper and discuss any environmental claims on the packaging: e.g. recyclable, contains oxygen bleach rather than chlorine bleach.
  • Do the toilet tissue experiment outlined on the activity sheet.
  • Compare what happens to your toilet paper with someone else.

Reflect & summarise

  • Come to a ‘conclusion’ about what type of toilet paper is the most environmentally sound: i.e. easiest to treat at a treatment plant.
  • Note: Materials that stay in larger pieces are best, as they are removed in one of the first 2 screening stages at the treatment plant. Small, slushy pieces (and dyes) must be chemically removed or will enter the ocean in the wastewater.
  • Discuss environmental claims on packaging. Draw conclusions for: unbleached, oxygen bleached.

Extension activities

  • Write an exposition, or debate environmental issues: i.e. hemp vs paper (refer to First Steps Writing: To Persuade).
  • Do some further research on biodegradable products (refer to First Steps Reading: Teaching Students to Access and Use Information).
  • Discuss labelling and packaging.
  • Book a school talk on what happens at a wastewater plant.

Teacher background information

Problems at the treatment plant

Rags, combustible waste matter and sand are often received at a treatment plant via the wastewater system. This material damages the expensive plant and equipment needed to process the megalitres of legitimate waste poured down sinks and other household drains and flushed through toilets every day.

It can take 4 or 5 people and cost thousands of dollars to rectify a problem caused by a blockage. The wastewater system is being choked with items such as cotton buds, wool, plastic items, used syringes, needles, razor blades, golf balls and jam jars. As the system is operated and maintained by people, their safety is jeopardised when these objects are dumped into sewers.

What we can do?

Ways of overcoming these problems and helping to protect the environment:

  • Use environmentally friendly (biodegradable) products.
  • Wrap waste cooking oil and grease and place it in the rubbish bin.
  • Don’t put chemicals like paint, kerosene, garden poisons, polishes or cleaning products down the sink, drain or toilet.
  • Use less detergent.
  • Compost waste kitchen products such as food scraps, tea leaves and coffee grounds.
  • Wrap disposable products like nappies, cotton buds and toilet deodorant packs and place them in the bin.

Did you know?

Wastewater is 99.97% water.

Key vocabulary

  • Decomposition (of wastewater): the breakdown of organic matter in wastewater by bacterial action, either aerobic or anaerobic
  • Grit: the heavy suspended matter in water or wastewater, such as sand, gravel or cinders
  • Household wastewater: water derived from dwellings, containing toilet, bathroom, laundry and kitchen wastes
  • Primary treatment: the first major treatment stage in a wastewater treatment facility—usually sedimentation
  • Screenings: material, such as rags, removed from wastewater by screens