Landfills are the most economical (and easiest) solution to this issue.
Recently over 200 international scientists conducted the most comprehensive global survey and found that 44% of the Globe's land masses are unihabited wilderness ares.
This 44% contains only 3% of the Globe's polulation.
It is safe to say that considering this information, the real issue is not where to put our trash, it's really about why we are not using the resources we already have.
"It was, of course, a lie what you read about my religious convictions, a lie which is being systematically repeated. I do not believe in a personal God and I have never denied this but have expressed it clearly. If something is in me which can be called religious then it is the unbounded admiration for the structure of the world so far as our science can reveal it." - Albert Einstein