I use sometimes P.arundinacea in my CWs (cf paper attached for example) and this species seems higly tolerant to a wide range of growing conditions. So, even if I can not ensure it, I think it won't suffer in your "artificially aerated CW".
This species is highly invasive in wetlands: wet prairies and fens in particular. I would be very careful that the species does not escape form constructed wetlands.
Farmers have been using Phalaris for years in "aerated" situations, so no, I do not believe that artificial aeration will have any adverse effects on the plants. In many CW aeration helps to eliminate toxic chemical species, though we have usually preaerated the effluent prior to entering the CW.
As for Phalaris being invasive, it is a prolific seeder, and will also spread vegetatively, which is why it is a desirable species for constructed wetlands. Controlling the seeding in a CW is also not too difficult.