Personally, I can't feature throwing extraction "waste" into the trash, or down the toilet.
You have to compost, obviously.
D-limonene is an oil that the citrus fruit uses to keep bugs away and is rather deadly to many types of insect. If you are serious about composting, your pile or bin is likely full of very good bugs. You do NOT want to kill them, they're doing good work. Even orange peels, when composted, should be broken up into small bits and spread out/mixed in with other material so as not to be too concentrated.
What I'd suggest is having two compost piles or bins. One short term, one long term. The long term is for denser material, straw, leaves, small twigs, paper products and such-like. The short term for food waste, more immediately compostable stuff in general, and also some leaves/paper products for heat--well, you find your own way. There's plenty of info and different styles out there.
My point is to have a longer term compost, one that you will not be expecting to use in your garden for a year or more. Take your extracted and spent and limo laden plant matter and mix it well with leaf mulch, dilute it way down and add it to the long term compost.
Ethanol of course can be evaporated. Still, most any tek, even eco teks (or granola teks as I've seen them disparagingly refered to) are going to use strong bases, acids. Your compost has a delicate balance.
I hope this advice is helpful. If anyone else has other tips, or if I'm going about this wrongly, then I'd love to be set straight.
"Whoever undertakes to set himself up as a judge of Truth and Knowledge is shipwrecked by the laughter of the gods." Albert Einstein
I appreciate your perspective.