THE QUEST FOR SUSTAINABLE NITROGEN REMOVAL TECHNOLOGIES

Evaluation of various processes and technologies to remove the inorganic nitrogen in wastewater and restore the global nitrogen balance and the anthropogenic nitrogen cycle through physical-chemical and biological processes, conventional and advanced nitrification and denitrification in activated sludge systems, algal ponds, duckweed ponds and constructed wetlands. 6 indicators were used : sludge production, energy consumption, resource recovery, area requirement and N2O-emission. The process of autotrophic N-removal which combines nitrification via nitrite and anaerobic ammonium oxidation is a very sustainable process.