CLONIC - Closing the nitrogen cycle from urban landfill leachate by biological nitrogen removal over nitrite and thermal treatment

The project demonstrated the effectiveness and environmental benefits of an innovative process for the treatment of leachate from landfills. The process included treatments based on a partial biological autotrophic oxidation of ammonium to nitrite (PANI-SBR process), followed by an autotrophic anaerobic ammonium oxidation via nitrite (Anammox process). Following this, thermal drying treatment using biogas as an energy source was carried out. The process was successful and nitrogen removal of 98% was achieved. Further, the Thermal Drying technology has shown to be an effective process for salinity influents, as all the salts were withheld in the solid phase, and the gaseous emissions had a pollutant concentration much lower than the legal limits. The environmental benefits of the process are numerous, along with reduced economic costs. In addition, the biological process developed has a wide range of applications as it can be adjusted to any effluent with high contents of ammonia and salts, such as wastewater, anaerobic digestion effluents, pig slurry or industrial processes. A full-scale plant to test the process is going to be implemented in the frame of another project - PANAMMOX (funded by the Spanish government).