A water treatment company in Malaysia uses aluminium sulfate (alum) in the water purification process. What is the purpose of adding aluminium sulfate?

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Question

A water treatment company in Malaysia uses aluminium sulfate (alum) in the water purification process. What is the purpose of adding aluminium sulfate?

Accepted Answer

to cause small particles to clump together so they settle out — Award 1 mark for C. Aluminium sulfate acts as a coagulant (or flocculant), causing small suspended particles to clump together into larger particles (flocs) that settle out during sedimentation. A is incorrect because chlorine is used for disinfection. B is incorrect because ion exchange or washing soda removes hardness. D is incorrect as this is not the primary purpose.

Answer

to kill bacteria and viruses in the water

Answer

to remove hardness from the water

Answer

to cause small particles to clump together so they settle out

Answer

to adjust the pH of the water to neutral

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