screening = water is passed through screens to remove objects such as sticks, leaves and litter
sedimentation = water is stored in settling tanks. Large insoluble particles sink to the bottom as sludge. Water can then be drawn off, leaving the sediment behind
A) sedimentation
B) sludge
C) insoluble particles
Filtration = Water is passed through system of filter beds made of sand, removing small insoluble particles. Bacteria are small enough to still pass through filters.
Chlorination = toxic chlorine is added to water to kill bacteria present, leaving water safe to drink.
