Anaerobic Protein Degradation for Resources Recovery from Nitrogen-Loaded Residual Streams

The demand for reactive nitrogen, i.e., ammonia (NH3), is constantly growing as the global population grows, especially in the nitrogen (N) fertiliser production sector. Simultaneously, the reactive nitrogen in residual streams, i.e., mainly ammonium (NH4+) and nitrate (NO3-), has caused serious environmental issues, e.g., eutrophication and species diversity loss. NH3 is produced from non-reactive nitrogen gas (N2) by means of the energy-intensive Haber-Bosch process. Typically, reactive nitrogen is converted back to the non-reactive N2 by nitrification and denitrification in wastewater treatment plants at the cost of energy. To reduce the overall energy demand and reduce the pool of reactive nitrogen in the environment, a potential solution can be the recovery and reuse of NH3 and NH4+ (Total Ammoniacal nitrogen, TAN) from N-loaded residual streams. Ongoing TAN recovery research has mainly focused on the efficiency of different available technologies from the perspective of a specific application of the recovered TAN. One important aspect, the availability of N-loaded residual streams and their compositions, is overlooked: there is a lack of identification and characterisation of the potential streams for TAN recovery…