I admittedly don't know much about this byproduct, and I do see mentioned that it's highly acidic. But if it causes algae blooms it makes me wonder if there's some sort of processing opportunity that could repurpose it for fertilizer.
> Continued problems with vinasse-dumping marred the sugar-ethanol industry’s environmental image, even as specialists encouraged repurposing the nitrogen-heavy byproduct as a fertiliser. Today, compliance with anti-dumping legislation is still not effectively enforced.
"In the past, vinasse was a problem in production of ethanol, but vinasse is also a good fertilizer (at least for some time) and a source of methane that can be used to generate heat or electricity. Moreover, other uses of vinasse involving also the formulation of nutritive solutions for hydroponics, formulation of culture media for plant tissue culture and culture media for algal growth."
Seems like it's only a problem because it's being dumped and not being purchased for reuse.