1. There are a few ways to purify water during hiking:
– Sand filter,
– Purification tablet,
– Evaporation distillation.
All three methods are somewhat used by municipal water supplies. Sand filter is comparable to filtration; Purification table is comparable to coagulation; Evaporation distillation is comparable to industrial size distillation plant.

2. Because it is extremely expensive due to excess power requirements, and only affordable by rich country like UAE.

3. a) Because of the corrosion of lead pipes, solder found on drinking fountains of water tanks.
b) Most probably not since they should be using an isolated system away from the water system.

4. Based on the phrase ‘like dissolves like’, polar will dissolve polar and non-polar will dissolve non-polar. Therefore, water-soluble compounds are polar since water is a polar compound and fat-soluble compounds are non-polar since fat is a non-polar compound.