Material that is left over or that is unwanted after something has been made, done, used, etc.
Waste
(American English) - Things that are no longer useful or wanted and that have been thrown out; often used to refer specifically to food waste that is being thrown out.
Garbage
Would you drink recycled __________? Part of the reason why people would not drink is because "we're reluctant to imbibe anything we think has been in the toilet". (livescience.com)
Sewage