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Mueller to Work on $2.6M DARPA Collaboration Grant

November 13, 2017

Anammox technology, as daunting as it sounds, is a scientific approach for reducing the cost and energy required to treat wastewater using nitrite rather than oxygen to remove ammonia and break down waste.  While used by some wastewater operations, the technology can currently only be applied to warm ammonium-rich side streams, limiting the number of treatment plants where it can realistically be implemented.

As part of a collaborative grant with the University of Washington and California Institute of Technology, Amy Mueller, assistant professor of the Department of Civil and Environmental Engineering, jointly appointed in Marine and Environmental Sciences (CEE/MES), will work on a $2.7M grant, funded by DARPA's Biological Robustness in Complex Settings program, to increase the robustness of Anammox technology for municipal scale-applications in the main processing stream.  Mueller received $400K of the total grant to work on development of the sensing and control systems at Northeastern.

Traditional wastewater treatment systems depend on aeration to provide enough oxygen for bacteria to break down waste matter or remove ammonia, which  can harm water quality. Anaerobic ammonium oxidation, or Anammox technology, on the other hand, breaks down waste matter and removes ammonia with nitrite supplied by aerobic ammonium oxidizing bacteria rather than oxygen; thereby reducing aeration requirements and in turn energy consumption.

Anammox technology garners many benefits relative to conventional treatment (nitrification/denitrification).  This includes a 50% reduction in aeration demand and a 75% reduction in space requirements, resulting in 30% lower operating costs.  Additionally, the technology maximizes nitrogen conversion to inert dinitrogen gas (N2), thereby removing nitrogen from the wastewater stream without nitrogen-based greenhouse gas emissions (e.g., N2O). 

To enable the implementation of the Anammox process, with its numerous benefits, at any treatment plant, the collaborative research team will harness a marine anammox consortium – a microbial partnership that functions at conditions similar to those in mainstream wastewater treatment – into unique bio-granules that optimally facilitate their cooperative waste processing, but successfully doing so requires improving online sensing to enable system stabilization at the niche conditions preferred by these microbes.  

System Stability

At Mueller’s lab at Northeastern, researchers will develop new sensing strategies to achieve the needed online measurements for stabilizing the Anammox bio-granular process at the target conditions (low ammonium, low oxygen, cool temperatures – representative of the main processing stream in most wastewater treatment plants).  Researchers will work specifically on biologically-informed machine learning algorithms for accurate measurement at low levels, which will be used to drive real-time feedback control strategies that ensure that reactor conditions remain stable across fluctuating environmental conditions to promote the targeted microbial communities.

Mueller remarked, “Water reclamation facilities consume approximately 2% percent of the annual US energy budget, and this strategy has the potential to cut that energy demand in half.  This project is an exciting example of the power of collaborative research and sharing of tools – especially data analysis strategies – across disciplinary lines.”