CANDO Research Grant Awarded to KJ by DOE

The DOE has awarded KJ a research grant for $1.99M to develop a new technology to reduce the greenhouse gas (GHG) emissions of traditional nitrogen removal processes at water resource recovery facilities (WRRFs). The research will be conducted in partnership with Dr. Zhiyue Wang at the University of Hawaiʻi at Manoa and will be piloted in partnership with the City and County of Honolulu at the Waianae Wastewater Treatment Plant in Waianae, HI. 

This GHG reduction is carried out in the form of N2O recovery and its subsequent usage for combustion of biogas. The side-stream technology used for this purpose is termed CANDO, short for Coupled Aerobic-anoxic Nitrous Decomposition Operation. This process converts the ammonia-N present in the anaerobic digestion waste stream to N2O. Otherwise, this ammonia-N is returned to the headworks and will contribute to the overall GHG emission of a WRRF through N2O emission during biological nitrogen removal processes, in the mainstream treatment train.  

CANDO process consists of two stages:  

• Nitritation: where ammonia is oxidized to nitrite under aerobic conditions 

• Denitritation: the reduction of nitrite to N₂O under anaerobic and anoxic conditions.  

Then, the N2O would be recovered and co-combusted with biogas at Waianae Wastewater Treatment Plant, with a potential to see a 50 percent reduction in GHG emitted from nitrogen removal processes in wastewater treatment. Other project goals include an 80 percent nitrogen removal rate and a 60 percent nitrous oxide conversion rate through this process. This research also ties into the overall goals of Waianae Wastewater Treatment Plant to implement co-digestion and co-generation at their plant, spearheaded by KJ’s team in Hawaiʻi led by Mike Joyce and Alicia Suzuki.  

Other project partners include Dr. Tao Yan from University of Hawai’i at Manoa and  Capstone Microturbine Inc. (Capstone), who is the industry partner in the project providing expertise for N2O recovery and co-combustion in their microturbines.   

“Along with our colleagues at the University of Hawaiʻi and the City we will be piloting this technology, and this funding will allow us to really explore the feasibility of how we can implement and scale this tech,” says Bhargavi (Gavi) Subramanian, Ph.D. and senior staff scientist at KJ and the principal investigator of this grant.  

“There are GHG emissions from several biological nitrogen removal processes and in addition it’s incredibly energy-intensive to treat wastewater, even when we get creative about biosolids and other waste-to-energy processes. Any and everywhere we can, we need to find ways to make existing treatment processes more efficient and look to reducing GHG emissions of these types of facilities.” 

This grant was part of $27.8 million allocated for 10 projects and distributed by the DOE Industrial Efficiency and Decarbonization Office (IEDO). IEDO is responsible for investing in funding, research, and more that will support innovation and adoption of cost-effective technologies to decarbonize the industrial sector in the U.S. 

All 10 selected projects focused on decarbonizing the entire life cycle of WRRFs and are poised to have a significant impact on moving the U.S. closer to a net-zero economy by 2050. 

For more information about the selected projects, click here: Industrial Efficiency and Decarbonization Office funding selections.