I know this thing in japan how horrible but now they are dumping?

Question:

their radiation stuff in the sea they claim it is low levels but dumping 11500 tons in the sea how fast does waters flow and will these folks in japan treat water before it goes to far

Answer:

Yes to answer your question they are dumping radiation into the ocean.

No they cannot treat the water once its in the ocean, there is no means to scoop it up and bring it back, its already there.

Its a choice between that, or letting the plant catch fire and spread radiation throughout the entire planet through the air.