$1.$ Give an example of a sorption$-$based process used for the remediation of contaminated soils.

$2.$ What is a dimensionless number and how can it be used for simplifying the solution of the ADR equation? Give an example of a dimensionless number often used by environmental engineers.

$3.$ Give two examples of environmental processes based on the two$-$film theory.

Please use the appropriate citation. Missing citation will be considered as plagiarism without grace.

word numbers between $50$ to $500$ to each