Which of the following process does not take place in domestic water treatment?

Step 1: Analyze the question We need the process that is NOT part of domestic (municipal) water treatment.

Step 2: Recall the stages of domestic water treatment

1. Screening: removes large debris.
2. Coagulation/Flocculation: alum (aluminium sulphate) is added so tiny suspended particles clump together into flocs. So B is part of treatment.
3. Sedimentation: the heavy flocs settle at the bottom of the tank. So D is part of treatment.
4. Filtration: water passes through sand and gravel beds to remove fine particles.
5. Chlorination: chlorine is added to kill disease-causing germs. So A is part of treatment.
6. Sometimes pH adjustment is done with lime or soda ash. Strictly, though, this is a minor correction, not a standard main stage.

Step 3: Check each option

• A. Chlorination: takes place (disinfection).
• B. Flocculation: takes place (clumping of particles).
• C. Neutralization: not one of the standard stages of domestic water treatment taught in the WASSCE syllabus.
• D. Sedimentation: takes place (settling).

Step 4: Conclusion The standard sequence taught is: sedimentation, coagulation/flocculation, filtration, chlorination. Neutralization is not among them, so it is the process that does not take place.

Exam tip: Remember the water treatment order with "S-C-F-C": Sedimentation, Coagulation (flocculation), Filtration, Chlorination. Any process not on this list, like neutralization, is likely the odd one out.