You don't have to see the world through the eyes of the market, says David Ransom.
Tanneries are pretty filthy places.
To make leather from the hides of cattle they use chemicals which combine to form a toxic sludge that is virtually impossible to make harmless. Tanneries are common in southern Brazil, where cattle graze on grasslands that once were forests, and so there is a big sludge problem too. He took a fresh look at the tanning process. Then recycle them - for some, like chrome, are expensive as well as toxic. The tanneries would thereby become cleaner and more efficient.