A wastewater treatment plant in British Columbia may soon turn sewage into biocrude oil, thanks to research carried out at the U.S. Department of Energy's Pacific Northwest National Laboratory (PNNL).

The technology, hydrothermal liquefaction (HTL), mimics the geological conditions the Earth uses to create crude oil. It does this by applying high pressure and temperature to achieve something that takes nature millions of years. The resulting biocrude material is similar to petroleum pumped out of the ground—with a small amount of water and oxygen mixed in. It can be further processed using conventional petroleum refining operations.

Biocrude oil looks and performs similarly to fossil petroleum. Image source: Water Environment and Reuse FoundationPNNL has licensed its HTL technology to Utah-based Genifuel Corp., which is working with Metro Vancouver, a partnership of 23 local authorities in British Columbia, to build a demonstration plant scheduled to enter service in 2018.

Sewage sludge, has long been viewed as a poor ingredient for producing biofuel because it is too wet. PNNL's approach eliminates the need for drying required in a majority of current thermal technologies that historically has made wastewater to fuel conversion too energy intensive and expensive. HTL may also be used to make fuel from other types of wet organic feedstock, such as agricultural waste.

Using hydrothermal liquefaction, organic matter such as human waste can be broken down to simpler chemical compounds. The material is pressurized to 3,000 pounds per square inch—nearly 100 times that of a car tire. Pressurized sludge is then fed into a reactor system operating at about 660 degrees Fahrenheit. The heat and pressure cause the cells of the waste material to break down into biocrude and an aqueous liquid phase.