A company has a volume of contaminated water that needs to be separated through evaporation. what would allow the mixture to be separated in the shortest time?

Evaporation will be a good method then for separating a soluble solid from a liquid (a soluble substance does dissolve, to form a solution). The contaminants on the water are solid substances, which will remain when water is evaporated. For example copper sulphate crystals can be separated from a solution using evaporation. Remember that it is the water that evaporates away, not the solution.