Recovering Energy From Nitrogen in Wastewater

Stanford postdoctoral scholar Yaniv Scherson began his career building rockets for space applications, but these days he is exploring a much more humble frontier: wastewater.

Through a partnership between Stanford University and the Delta Diablo Sanitation District in Antioch, Calif., Scherson will soon test at pilot scale (1/100^th full scale) a process he developed to recover renewable energy from nitrogen in wastewater. If it works at the Delta Diablo wastewater treatment plant, the process could be adopted elsewhere as a way of producing, continuous clean energy.

The process, coupled aerobic-anoxic nitrous decomposition operation (CANDO), converts wastewater nitrogen to nitrous oxide gas, then uses the gas to increase the power output of engines at wastewater treatment facilities.

Many wastewater treatment facilities already recover renewable energy from wastewater as biogas. Coupled with CANDO, wastewater treatment facilities can export renewable energy to end users from a free and continuous source. 

Scherson and his team at Stanford developed the concept with a two-year Environmental Venture Project grant from the Stanford Woods Institute for the Environment beginning in 2009, under the leadership of Professors Brian Cantwell (Aeronautics and Astronautics) and Woods Senior Fellow Craig Criddle (Civil and Environmental Engineering). Once they demonstrated the technology in a Stanford laboratory with synthetic wastewater, the researchers wanted to move the research into the real world of wastewater treatment.

After contacting several wastewater agencies in the San Francisco Bay Area, the team formed a partnership with Delta Diablo in Antioch and set up a bench-scale system in their lab in 2012. The system was successful. Now the team is building a pilot-scale demonstration unit at the Delta Diablo wastewater plant, which runs 24 hours a day, every day of the year.

“Delta Diablo’s innovative and motivated team of environmental stewards made this a natural and successful partnership,” said Scherson.  “I also believe the east Contra Costa County corridor is uniquely situated and well suited to become a hub for water innovation due to its close proximity to several major universities, transport systems and the Delta.”

The TomKat Center for Sustainable Energy at Stanford University is funding the hardware for the pilot project. Other support is being provided by the National Science Foundation Engineering Research Center for Reinventing the Nation’s Urban Water Infrastructure (ReNUWIt), an additional National Science Foundation grant and a grant from Veolia Water. 

Heading up the project at Delta Diablo is Environmental Compliance Engineer Amanda Roa, who reports, “Delta Diablo is extremely proud to have been selected by Stanford University to partner with such an esteemed group of researchers. Exploring and supporting this project reflects our resource recovery mission by supplementing our existing renewable energy production to help offset costs of running our plant.”

The pilot-scale project will begin soon at Delta Diablo in Antioch and is expected to run for at least 12 months.

Angela Lowrey is the public information manager for the Delta Diablo Sanitation District.

By Angela Lowrey