Energy from microbes for drying sewage sludge

A new biodrying process from Siemens quickly converts sewage sludge into a usable form while saving energy. When dried with the new process, sludge from wastewater treatment can be used as fertilizer, dumped in landfills or incinerated. Unlike thermal drying processes, the new technique, known as "mechanically enhanced biodrying" or MEB, does not require any outside source of heat. Instead, it uses the energy produced by microbes in the sludge. The operational costs are therefore 30 percent lower compared to thermal drying processes.

http://phys.org/news/2012-08-energy-microbes-sewage-sludge.html