Researchers say this could eventually change the way that wastewater is treated all over the world, replacing the widely used "activated sludge" process that has been in use for almost a century.

ENGADGET: Researchers create super-efficient microbial fuel cell, dream of selling excess electricity

The method uses biogas, which is produced when waste water sludge is broken down by microbes in a process known as anaerobic digestion.

BBC: United Utilities turns human waste to energy at plant

Fueled partly by billions in government incentives, the industry is creating millions of solar panels each year and, in the process, millions of pounds of polluted sludge and contaminated water.

NPR: Solar Industry Grapples With Hazardous Wastes

In many cases, a toxic sludge is created when metals and other toxins are removed from water used in the manufacturing process.

NPR: Solar Industry Grapples With Hazardous Wastes