The half life is 12.3 years. If the amount of water was not growing it wouldn't be a huge problem. The tanks they are building will probably last at least 40+ years before having to be replaced, at which point we're talking about water that is not all that dangerous. If you release a tiny bit at a time it shouldn't be a problem.
However the water keeps accumulating. I don't think that part is sustainable. Until they fix the root cause of a seemingly endless amount of water that needs to be stored, this is going to be a problem.
The half-life of Tritium is 12.3 years. So as long as substantially everything with longer half-life has been removed, storage for a century or so would suffice.
Maybe put it in a bunch of large bags and tow it to Antarctica. But you'd need to avoid the bits that are already collapsing.
Bury where there's already plenty of radioactivity. It does occur in nature, I hear.
The more radioactive it is, the shorter the half-life, right?