Oshidori mako asks:
When Tepco purifies contaminated water, a Reverse Osmosis Membrane is used, but strontium is water soluble so you need ion-exchange filtration or coagulating sedimentation to remove it from the contaminated water. -> How do you filter strontium out?
Tepco, Matsumoto answers:
When the equipment of AREVA was working, we used coagulating sedimentation to filter out strontium.
However, now that AREVA’s equipment is out of order. – Strontium is not filtered out.
Oshidori mako asks:
I understand that water is not leaked to the sea now, but when water WAS leaking into the sea from Reactor 2, how did you filter out strontium?
Tepco, Matsumoto answers:
No, we haven’t filtered out strontium. Strontium must have leaked to the sea.
(Source)