Making Wastewater Treatment Energy Neutral with Deammonification

WERF is currently exploring new research into an innovative process that has the potential to change the way we perform wastewater treatment. The study Full-Plant Deammonification For Energy- Positive Nitrogen Removal targets the next generation of deammonification processes by expanding deammonification into the mainstream liquid treatment train for fullplant nitrogen removal.

The successful application of full-plant deammonification could save wastewater utilities hundreds of millions of dollars in aeration and external carbon costs in the treatment cycle. For municipalities, wastewater treatment plants (WWTP) frequently have the largest requirements of energy because significant energy is used to provide aeration to oxidize organic carbon and ammonia. This research will demonstrate energy neutral or even energy-positive wastewater treatment and reduction of external carbon for nitrification by applying a more efficient alternative biological pathway. It will show that this innovative technology is compatible with existing wastewater infrastructure, often with minimal modifications.

The 1990s discovery of “annamox” bacteria allowed the development of wastewater treatment concepts that apply advantageous metabolic pathways unique to this microorganism. Deammonification” involves anammox bacteria working synergistically with ammonia oxidizing bacteria (AOB) to oxidize ammonia without organic carbon to produce nitrogen gas. The process requires significantly less oxygen to remove nitrogen, and less energy is needed for aeration. A decade ago, Dr. Bernard Wett developed a process called Demon when he found could culture these organisms to remove the concentrated nitrogen in sludge dewatering recycle streams.

It is now almost common practice to use Demon in Europe and several WERF subscribers including DC Water and Hampton Roads Sanitation District (HRSD) are building Demon plants. Presently, fullscale applications of deammonification processes remove nitrogen from warm, ammonia-laden dewatering sidestreams derived from anaerobically digested solids. This research targets the next generation of deammonification processes by expanding deammonification into the mainstream liquid treatment train for fullplant nitrogen removal.

The research consists of two phases. Phase I will operate physical facilities planned by DC Water and HRSD, to demonstrate the feasibility of the proposed full-plant deammonification process. Resulting data from Phase I will be used to expand research to develop more general guidelines. Phase II includes developing tools to aid engineers and operators in applying full-plant deammonification at full-scale for various process configurations at North American wastewater treatment plants.