The U.S. Department of Energy awarded Kennedy Jacks, a water and environmental engineering firm with an office in Honolulu, a $2 million grant to develop technology to reduce greenhouse gas emissions from wastewater treatment facilities.

Kennedy Jacks will work with a research team at the University of Hawaii at Manoa to investigate a new process that could decrease the environmental impact of traditional nitrogen removal methods in wastewater treatment. 

Removing nitrogen from wastewater is important because excess nitrogen leads to harmful algae blooms in lakes and oceans. However, conventional wastewater treatment processes release a large amount of greenhouse gasses.

The environmental firm and UH research team will work with the City and County of Honolulu to run pilot-scale testing at the Waianae wastewater treatment facility starting in 2025. 

“By developing technology that can reduce greenhouse gas emissions from wastewater treatment while potentially increasing energy recovery, we’re not only addressing global climate concerns but also working towards greater energy independence for our island communities,” said Zhiyue Wang, who is an assistant professor in the Department of Civil, Environmental and Construction Engineering and part of the UH research team. 

The project involves the development of the Coupled Aerobic-anoxic Nitrous Decomposition Operation process. This process converts waste nitrogen in the form of ammonia, a common component in wastewater, into nitrous oxide. The nitrous oxide is then collected and burned alongside biogas, improving the energy efficiency at treatment facilities. 

Through this method, researchers hope to achieve an 80% nitrogen removal rate and a 60% nitrous oxide conversion rate. If successful, this technology could reduce greenhouse gas emissions from nitrogen removal processes by more than 50%.