How would you separate a mixture of oil ,water and sand?

Pass the mixture through a filter mesh, this will separate the sand from the oil/water mixture. The sand can then be washed with some solvent to remove any traces of oil, and then dried out.

to give the reader a sense of the chaos, fear, and havoc taking place

true. the definition explains it: a word or phrase that modifies or qualifies an adjective, verb, or other adverb or a word group, expressing a relation of place, time, circumstance, manner, cause, degree, etc. this is a dictionary definition that i have looked up in a dictionary.