Vast human waste with any number devoted to luxury (9)
I believe the answer is:
Here is my best explanation:
'devoted to luxury' is the definition.
'vast human waste with any number' is the subsidiary indication.
'vast' becomes 'epic'.
'human waste' becomes 'urea'.
'with' says to put letters next to each other.
'any number' becomes 'n' (I've seen this in other clues).
(Other definitions for epicurean that I've seen before include "Given to sensual enjoyment", "Gourmet", "one sensuous and Greek", "One appreciating food and drink", "Foodie's", "enjoyer of fine food", "pleasure-seeker", "Bon vivant", "expert at the table" and "follower of luxury".)