Removing and converting ammonia from high-strength wastewater can be a challenging process that requires particular biological nitrification treatment methods in order to be effective.
Grontmij's DEMON® system, a new energy-saving nitrification/deammonification technology, is a process that simultaneously converts nitrite and ammonia into valuable nitrogen gas at wastewater treatment plants without the use of organic carbon.
Conventional systems convert ammonia in wastewater into nitrate, requiring more oxygen. They also require an organic carbon source to convert that nitrate into nitrogen gas, resulting in a larger carbon footprint. The DEMON process eliminates the need for all chemicals, and nitrite instead of nitrate is the end product of nitrification. Moreover, this reduces energy requirements by 60 percent and sludge production by 90 percent.
Delivered by Grontmij, a Netherlands-based consulting and engineering company, and developed by the University of Innsbruck, the technology had only been used in Europe until recently when World Water Works, Inc., a designer and manufacturer of wastewater treatment solutions and Virginia utility Hampton Roads Sanitation District (HRSD), installed the first system in North America. Both companies received the American Association of Environmental Engineers and Scientists (AAEES) Honor Award for Environmental Sustainability for their efforts.
HRSD's York River Treatment Plant proved to be a perfect candidate for the DEMON system because its existing sequential batch reactors (SBR) and equalization tanks could easily be retrofitted for the process, allowing for simple and inexpensive installation in less than four months. Successful operation has continued since early January.
Grontmij's technology removes ammonia from wastewater in a biological process utilizing ammonia-oxidizing bacteria (AOB), which converts half of the ammonia to nitrite. Further, an anaerobic biological process uses Anammox bacteria to convert the combination of nitrite and remaining ammonia directly into nitrogen gas.
Seeded throughout the system, the Anammox bacteria help accelerate the nitrification/deammonification process, as opposed to conventional methods that require bacteria to be cultivated from scratch. Despite their different growth demands, both nitrifying and deammonifying bacteria are capable of co-existing in one single reactor volume as a result of the DEMON process.
The DEMON process has been installed at more than 20 full scale installations in Europe. For more information on the new technology, visit www.grontmij.com.