Answer:
kitchen sink
Step-by-step explanation:
Blackwater is a mixture of the substances that come from cleansing water and greywater is the one that comes from the things that are not in the toilet.
Greywater that should be considered as blackwater is water from the sink. It contains fats and oils and many organic substances.
Blackwater has a big range of materials that put it into this classification. It should be treated with chemicals for disinfection.