Susan Bauer from the Pacific Northwest National Laboratory published a story in November 2016 about the PNNL’s progress in creating fuel from biowaste. The hydrothermal liquefaction process used in the article takes inspiration from the high pressure and high temperature conditions that the Earth uses to manifest crude oil.
Pretreatment of the solid waste removes grit and effluent water from the sludge before moving to a hydrothermal processor where the sludge is estimated to be around twenty percent solid. An ongoing project with Genifuel and MetroVancouver is building a prototype plant to scale up the process. The $9,000,000 (Canadian) cost is expected to be funded by MetroVancouver and outside investors. Planning will take place in 2017 after funding is secured and operation beginning in 2018.
The hydrothermal liquefaction equipment developed by this team uses pressures around 3,000 pounds per square inch and temperatures up to 660 degrees Fahrenheit to split into biocrude and an effluent water, the most widely used process takes less than sixty minutes. In previous decades human waste was perceived as too expensive to convert to biofuel because the waste held too much moisture and drying processes need to be included in the conversion from sludge to fuel. The high pressure, high temperature used in hydrothermal liquefaction is expected to remove the drying requirements from the process, yielding more efficiency and cost benefits.
PNNL has been working on biowaste fuels for at least forty years, working with algae to digest wood and other wastes. Several articles and patents have been published through the Pacific Northwest National Laboratory. This renewed push toward human waste biocrude has a wide range of possibilities. Phosphorous has been recovered from the residual solids that end up after the process, and several different livestock wastes have been targeted and tested. This is exciting longterm technology that has potential to take some of the estimated 34 billion gallons of waste produced every day in America and create energy.