Citrus isn't so great for anaerobic digestion but it generated a bit of a discussion in one of my fb groups.
Thomas Gram sent this interesting article about an emerging solution for bio-remediation using an extract from citrus peel with sulfur to pull mercury and palladium out of polluted water and soil.
And then I saw this article on what happens to barren land when you dump tons and tons of citrus peel and wait long enough.