Here is what we have done 20 ...

Here is what we have done 20 years ago. We had a similar filamentus bloom situation and client wanted to get rid of the foam as soon as possible. we did some jar tests to determine practical chlorine dose to destroy bacterial cell wall. (white color indicates that), then estimated the chlorine volume by multiplying with aeration reactor. After that we stopped the aeration for 15 minutes making sure that good bacteria settles, then threw the chlorine to the surface destroying the foam at high concentration, by the time chlorine reaches to the bottom diluted and not to damage the "good" bacteria. waited for a while. then re-started the aeration system foam was gone. :) 

We took the risk, but it worked that time. Don't try this without precisely estimating the dose with multiple jar tests. Otherwise you might destroy good  bacteria as well.