“D.C. Water, which also treats sewage from much of the Maryland and Northern Virginia suburbs, recently became the first utility in North America to use a Norwegian thermal hydrolysis system to convert the sludge left over from treated sewage into electricity.”
The Washington Post put up a great article showing illustrations of this new system and how it works. This system has been said to be a lead in innovation and technology for the world, and private and public water companies are viewing this as a possible example to replicate.
Even the leftover sludge plans to gets sold as fertilizer. Read more here.