It's black or white with grounds for disposal (6)

I believe the answer is:

coffee

I'm a little stuck... Click here to teach me more about this clue!

'disposal' is the definition.
The definition and answer can be both human attributes as well as being singular nouns.
Maybe they are linked in a way I don't understand?

I don't understand the rest of the clue.

Can you help me to learn more?

(Other definitions for coffee that I've seen before include "Eg, espresso" , "Popular drink made from ground beans" , "Something drunk - cafe in France" , "Aromatic table drink" , "Shrub; drink" .)

I've seen this clue in The Globe and Mail.

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