Water collected from a source typically goes through several processes at a water treatment plant before entering our homes as potable water. This activity allows students to investigate most of the following steps involved in water treatment and to suggest improvements to the treatment system:
- aeration – water is mixed with air to add oxygen
- coagulation and flocculation – substance added (e.g., potassium aluminium sulphate) to create sticky globules or ‘flocs’ which collect particulates and bacteria
- sedimentation – flocs and solids are allowed to settle out
- filtration – water travels through various substances to remove finer solids, flocs, and micro organisms
- disinfection – substance (usually chlorine) is added to kill bacteria
Make a pop-bottle water filtre yourself to use as a model for your students.