Rubbish heap's collected with great volume (6)
I believe the answer is:
piffle
'rubbish' is the definition.
(I've seen this before)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for piffle that I've seen before include "Stuff and nonsense" , "Cock" , "Informal nonsense, worthless talk" , "rot" , "Balderdash" .)