So doesn't the oil, gas, antifreeze, etc cause issues with the plant material after time?
There's a local medical center that was going for some sort of LEED cert that was going to use all the runoff from the lot for irrigation. Someone asked them what about all the salt that is applied during the winter collecting in these tanks, being applied to turf and plants.
You could have heard a pin drop.
Good point, I know (not much) about separators; wonder if the damn things work as far as plant material is concerned.