Recycling Tyres to Create 'Green Energy'

Check out this Connectmidmissouri article about a farmer (Harvey Buhr) who recycles tyres and turns them into fuel without emitting any pollutants into the environment! The article claims that "Buhr has machines in his backyard that can recycle a whole cart of tires at a time. Once they go in, Buhr uses heat to extract the oil and other energy sources inside of them."...""For every 1,000 pounds of tires that we process, we can generate 51 gallons of diesel fuel." We would be interested to find out how he accomplishes this and what is done with the trapped pollutants afterwards.