DEMON® reactor
DEMON® reactor
DEMON® sludge
DEMON® sludge

Industrial wastewater treatment systemsSingle-stage ammonium removal treatment - DEMON® Deammonification System

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Single-stage ammonium treatment DEMON® (an acronym for deammonification) is highly efficient and cost effective nitrogen treatment technique for wastewater containing high-strength ammonium. This method uses the anaerobic ammonium oxidation (AMX) bacteria. This treatment is suitable for nitrogen treatment of wastewater containing ammonium nitrogen of 200 mg-N/L or more, and has been commonly introduced for nitrogen treatment of dewatering centrate from anaerobic digestion especially in Europe and the North America. DEMON® is currently the most popular nitrogen treatment process utilizing (AMX) bacteria.

  • Reduction of the nitrogen treatment cost
    - Power consumption … Oxygen demand can be reduced by 60% compared to conventional nitrification and denitrification process.
    - Consumption of chemicals … Organic matter is not required for denitrification and alkali dosage can be reduced.
    - Excess sludge … Due to slow growth rate of AMX bacteria, excess sludge can be reduced.
  • Space saving
    - High-speed nitrogen treatment utilizing AMX bacteria. Simple system configuration
    - Biomass carrier is not required due to the licensed unique bacteria separation and accumulation method
    - Less equipment (tank, pump, etc.) compared to two-stage AMX process.
  • Simple system configuration
    - Biological carrier is not required due to the licensed unique bacteria separation and concentration method
    - Less constituting equipment (reactor, pump, etc.) compared to two-tank type.
  • Rich track records by DEMON GmbH
    - More than 40 installations in the world, mainly with dewatering centrate.
    - Pilot test of DEMON® has also been accomplished in Japan and high-performance of DEMON® treatment has been confirmed in side stream treatment.


For conventional nitrification and denitrification process, the metabolism of ammonium oxidizing bacteria and nitrite oxidizing bacteria has to be used to nitrify all the amount of influent ammonium to a level of nitrate.)

For AMX process, if 57% of influent ammonium is nitrified by aerobic ammonia oxidizing bacteria until they become nitrite (partial nitritation treatment), the generated nitrite and remaining ammonium are denitrified the last production of nitrogen gas through the metabolism of AMX bacteria and approximately 11% of influent ammonium is transferred converted to nitrate.

DEMON® process reduces the cost of nitrogen treatment by simultaneously maintaining partial nitritation and AMX reaction with one reactor by shortening the conventional nitrogen conversion of the nitrification and denitrification treatment.
This nitrogen treatment method is referred to as "deammonification".

Ammoniac nitrogen treatment

DEMON® is suitable for nitrogen treatment of wastewater containing 200 mg-N/L or more of ammonium nitrogen.

In particular, this treatment has been widely introduced for nitrogen treatment of dewatering centrate in Europe and the North America.
As of 2014, DEMON GmbH, the licensor of this process for deammonification technology, has already introduced full-scale facilities at 40 or more places. This makes DEMON® currently the most popular nitrogen treatment process utilizing AMX bacteria.

Outline of treatment

Batch treatment is performed by intermittently supplying raw wastewater while controlling aeration and stirring in order to make partial nitration and AMX reaction simultaneously at one reactor.
Sludge increases when nitrogen treatment is performed by the bacteria; however, the balance between nitrifying and AMX bacteria is maintained by selectively withdrawing nitrifying bacteria in the tank through a DEMON® cyclone. With this well-contrived treatment, stable and efficient nitrogen treatment can be achieved.

Energy self-sufficient wastewater treatment(Energy Self-Sufficient by DEMON (: EssDe®)

This is an energy self-sufficient energy wastewater treatment technology in which as much methane gas as possible is produced from anaerobic digestion and electric power of wastewater treatment facilities is maintained by power obtained from digestion gas power system by combining the wastewater treatment technology referred to as the "AB process" with nitrogen treatment technology utilizing DEMON®. 
EssDe® has been introduced at facilities Strass wastewater treatment plant in Austria and energy self-sufficiency was achieved in 2005.  Installation of EssDe® is currently still under study in Europe and validation test is also conducted in Japan.

Meiden received the technical license from DEMON GmbH, Switzerland for areas Singapore and Japan.  DEMON® and EssDe® are trademarks of DEMON GmbH.


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