Futurology

We entomb it in massive concrete caskets with a volume up to 5 000m², lined with plastic to prevent leaking, and when it's full we cap it and bury it under 3 meters of dirt.

It used to be around 1-2m wide clay bowls that were filled halfway and there was a variety of methods to cap it off. The reason for famines and things like the black death were people who just buried it in dirt, the cursed crap leeched out.