Potable Water and Treating Waste Water · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Turning river water into drinking water

Science · Matter & Materials · ages 15-16
Name ______________________   Date ____________

  1. What does chlorination deal with?

    • Branches and rubbish
    • Silt and mud
    • Bacteria and viruses

  2. What is the correct order of the drinking water stages?

    • Filter, chlorinate, screen, settle
    • Screen, settle, filter, chlorinate
    • Settle, screen, chlorinate, filter

  3. Potable water is exactly the same as pure water.

    Circle one:   True   False

  4. Which sewage stage pays back energy as biogas?

    • Screening out the solids
    • Aerated tanks with oxygen loving bacteria
    • Sealed digesters without oxygen

  5. Why is desalination used only where fresh water is scarce?

    • The sea holds too little water to matter
    • Boiling or pushing seawater through membranes drinks energy greedily
    • Desalinated water is unsafe to drink

  6. River water carries silt plus dissolved filth. Which pair handles each?

    • Settling drops silt while microbes in aerated tanks feast on dissolved filth
    • Chlorine drops silt while settling kills germs
    • Screens eat dissolved filth while filters pump air

  7. Aerobic tanks work without oxygen while sealed digesters need pumped air.

    Circle one:   True   False

  8. A student says every coastal city should desalinate since the sea is endless. What is the flaw?

    • Desalination costs far more per litre than treating river water
    • Seawater holds no salt worth removing
    • Membranes last forever with no upkeep
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Answer key

For grown-ups. Fold this page away before handing over the rest.

Turning river water into drinking water W1-mt_5qsFZJSmMO-s1

  1. Bacteria and viruses · Chlorine kills the germs that slip through every filter.
  2. Screen, settle, filter, chlorinate · Big debris first, then silt, then fines, with germ killing last.
  3. False · Potable keeps harmless minerals, while pure holds nothing but water.
  4. Sealed digesters without oxygen · The sealed anaerobic stage is slower but burps out useful methane.
  5. Boiling or pushing seawater through membranes drinks energy greedily · The energy bill per litre beats treating river water everywhere else.
  6. Settling drops silt while microbes in aerated tanks feast on dissolved filth · Sinking handles the heavy bits and hungry microbes handle the dissolved bits.
  7. False · The sentence swaps the two stages: aerobic needs air and anaerobic seals it out.
  8. Desalination costs far more per litre than treating river water · Endless supply means nothing when the energy bill per litre is huge.
Worksheet · LightMySky