There’s gold in them thar waste. But how can we mine it?

The billions of dollars worth of gold lurking in our electronic waste and - sewage systems. From the luxury industry to modern electronics, humans are infatuated with Gold - so how do we maintain the supply? Wendy Lee Queen and Mirko Bischofberger writing in Aeon ask if inventions to retrieve even the smallest amounts is a sign of our obsession going too far.