Municipal waste water treatment is undergoing a transition from classical activated sludge treatment at high energy costs towards becoming net energy producing through separation and digestion of primary sludge. This is done by the introduction of Anaerobic Ammonium Oxidation - Anammox or nitrite shunts for Nitrate removal, and biological phosphorus recovery.
The approach is based on initial stripping of the wastewater for most of its organic matter, and subsequent nitrogen removal by partial nitrification and anammox. The initially removed organic matter may be used for biogas production so that the wastewater plant will not only produce sufficient energy for pumps, aeration, etc., but will be net energy producing.
The system energy balance is improved dramatically through savings on aeration and extraction of methane from new anaerobic digestion technologies.
The low oxygen conditions, however, favor the production of the extremely potent greenhouse gas N2O. The system therefore needs to be carefully controlled and optimized to avoid significant emissions of N2O. The centre is currently working with leading water facilities in Denmark to implement and monitor such system.
In addition, conventional treatment also needs optimized energy and greenhouse gas budget. This can be provided for by online monitoring and are particularly important if the planned mainstream anammox fails and a nitrite shunt procedure is chosen instead.
Detailed microscale analysis of the chemistry and reaction rates around and within the aggregates of the activated sludge will be the basis for detailed modelling of the biological processes.
Detailed microscale analysis of the chemistry and reaction rates around and within the aggregates of the activated sludge will be the basis for detailed modelling of the biological processes.
