From time to time Florida developers have built housing developments on "land and lakes" tracts. It usually ends badly because the ground is unstable (still settling after all being mined), though post-tensioned prestressed concrete slab foundations can be used to reduce cracking (but not eventually uneven floors).
In my experience with phosphate industry sludge ponds, nothing much grows. I just looked at aerials from a tract southeast of Bartow that was under consideration for development in 1997. It had been out of service for almost twenty years back then. The ponds are no longer obviously toxic, but there is still does not appear to be normal Florida native vegetation along any of the shorelines.
Not surprising given how acidic phosphate sludge water is.
The fact that sea water can be stored in the leaking stacks over in Manatee county speaks to how sterile they are. The salinity of seawater is deadly to typical terrestrial plants.
Traditionally, Floridians call them "sludge ponds" as here, https://www.gainesville.com/news/20160929/mosaic-says-tests-...
"The water meets water quality standards for marine waters with the exception of pH, total phosphorus, total nitrogen and total ammonia nitrogen,"
"Marine water" itself will kill with three or four easy gulps, but I guess this wastewater is going into the ocean? It still sounds a bit too much like "yellow, except for the color, which is blue". Plus I'd expect any industrial wastewater to have lots of fun contaminants they haven't tested for and/or just don't have explicit limits set.
"A very aggressive monitoring operation"
There's a term I've been missing my whole life. It's my go-to action item priority one from now on when faced with...
"... everything possible to prevent a true catastrophe."
And untrue catastrophe?