This how it works covers How It Works: Water Treatment for Drinking Water within Water Treatment for GCSE Chemistry. Revise Water Treatment in Using Resources for GCSE Chemistry with 23 exam-style questions and 15 flashcards. This topic shows up very often in GCSE exams, so students should be able to explain it clearly, not just recognise the term. It is section 4 of 14 in this topic. Use this how it works to connect the idea to the wider topic before moving on to questions and flashcards.
⚙️ How It Works: Water Treatment for Drinking Water
Water treatment involves multiple stages to remove different types of contaminants:
1️⃣ Screening
Large debris (leaves, twigs) removed by metal grids
2️⃣ Sedimentation
Water sits in tanks — heavy particles settle to bottom
3️⃣ Filtration
Water passed through sand, gravel, and carbon filters
4️⃣ Chlorination
Chlorine added to kill bacteria, viruses, and pathogens
5️⃣ pH Adjustment
Lime added to make water less acidic (prevents pipe corrosion)
6️⃣ Fluoridation
Small amounts of fluoride added to prevent tooth decay
💧 Distillation (Alternative Method)
For highly contaminated water: Water is heated to steam, then condensed back to liquid. This removes all dissolved substances but requires lots of energy.
Practice questions for Water Treatment
What does the term 'potable water' mean?
Explain what happens to the sewage sludge produced during waste water treatment, and why this process is useful.