It is said that outlaw Willie Sutton, when asked why he robbed banks, replied, “Because that’s where they keep the money.”When it comes to recovering resources in clean-water plants, the money — and the energy — appear to be mostly in the solids. Water of course is the essential resource being recovered, and in many applications it has commercial value for reuse. But increasingly it’s the solids side that gets attention from the industry’s innovators.In particular, facility owners and operators see biogas (digester methane) as an essential resource that can help them on the path toward more energy self-sufficiency, net
