If oil can be pulled out of the sand and ultimately used in our cars, trucks, lawnmowers, etc why can't that same or similar process clean it once again? As mentioned, it's the additives more than anything that make up the "good" of the oil. Heck, read Mobil1's website - even what everyone refers to as a "pure synthetic" motor oil started life as dead dinosaur juice pulled out of the ground.

And if waste water can be recycled to where it's safe to drink, I'm pretty confident that these oil engineers can make a perfectly safe and usable motor oil from recycled stuff. Even if right now they can't quite do it to where it meets certain requirements for higher performance engines, give them time. Look at the differences between today's high tech oils and the stuff we were using in the '60s. Technology advances everything.