I work at a place where they manufacture fertiliser (among other things) and our mian problem with our waste water is the high nitrogen content. So all of our waste water is pumped into specifically designed wetlands where the bacteria turn it into nitrogen gas, altho there are various types of reeds in there as well to help with the nitrates and help get some air in there as well.
As far as i know its the only one of its kind in australia (if not the world). It was treating about 200 cubic metres (so 200 000 litres of water every couple of days), but it has just been expanded by 300%, so not sure what it can do now (haven't been in that area for bout 6 months), but think its bout the same but every day or 2 now instead of every couple of days, bein managed better and more nitrogen bein taken out.
I think the 1st cell was taking out bout 40-50% nitrogen, but has decreased over time and is now at bout 30% odd.
They think its due to lack of organic carbon left (they have another bacteria that converts it to nitrogen gas which needs a source of carbon, but it has to be organic as has to have some sugars in there).
I find it pretty interesting and alot of research has gone into it by murdoch university and the lab here as well (damn uni students dropping 30 samples off the week b4 christmas and wanting them done b4 new years, they don't understand that we just can't magically produce the results
)Cheers
Jono