There are actually two processes that they are using. Both are intended for use on farms, and both for after the fact of excretion. One of them is an agent that, when stirred in to the poop, keeps it from releasing any vapor. The other, more interesting one is supposed to block your smell receptors from noticing the poop smell: "…one part of the process takes advantage of a natural phenomenon known as olfactory cross adaptation, which happens when the nose adapts to one odor and then becomes less sensitive to a second smell that is perceptually or structurally different from the first."
Basically, your poop smell receptors are the same ones that receive some other smells. If they bind a pleasant or neutral smell with the poop, you don't smell it at all.
It seems that we just need to find a way to make this a food additive. If we could do that, then we could finally possibly carry out the proposal made by Benjamin Franklin in his essay Fart Proudly [2]. Mr. Franklin proposed an additive that would make one's farts smell good. As he puts it:
"To discover some Drug wholesome & not disagreeable, to be mixed with our common Food, or Sauces, that shall render the natural Discharges of Wind from our Bodies, not only inoffensive, but agreeable as Perfumes."
He believed that such an additive would make us feel more free to let loose the stinky goose, thus making us less anal retentive and healthier of mind and body. I ask you, dear reader, couldn't Dick Cheney do with a little freedom of the butt sput? Don't you think that Kim Jong Il might be a little nicer if he were not so bound up? Don't you think that some looser sphincters might aid in the pursuit of world peace? I'll leave you with Mr. Franklin's final say on the matter.
"In short, this Invention, if completed, would be, as Bacon expresses it, bringing Philosophy home to Mens Business and Bosoms. And I cannot but conclude, that in Comparison therewith, for universal and continual UTILITY, the Science of the Philosophers above-mentioned, even with the Addition, Gentlemen, of your "Figure quelconque" and the Figures inscribed in it, are, all together, scarcely worth a FART-HING."