excreta vs human waste

excreta and human waste both are nouns.

Word	Noun	Adjective	Verb	Adverb
excreta	Yes	No	No	No
human waste	Yes	No	No	No

As nouns, human waste is a hyponym of excreta; that is, human waste is a word with a more specific, narrower meaning than excreta:

excreta: waste matter (as urine or sweat but especially feces) discharged from the body
human waste: the body wastes of human beings

excreta (noun)	human waste (noun)
waste matter (as urine or sweat but especially feces) discharged from the body	the body wastes of human beings