The reported research developed a generic nutrient recovery model (NRM) library based on
detailed chemical solution speciation and reaction kinetics, with focus on fertilizer quality and
quantity as model outputs. Dynamic physicochemical three-phase process models for
precipitation/crystallization, stripping and acidic air scrubbing as key unit processes were
developed. In addition, a compatible biological-physicochemical anaerobic digester model was
built. The latter includes sulfurgenesis, biological N/P/K/S release/uptake, interactions with
organics, among other relevant processes, such as precipitation, ion pairing and liquid-gas transfer.
Using a systematic database reduction procedure, a 3- to 5-fold improvement of model simulation
speeds was obtained as compared to using full standard thermodynamic databases. Missing
components and reactions in existing standard databases were discovered. Hence, a generic
nutrient recovery database was created for future applications. The models were verified and
validated against a range of experimental results. Their functionality in terms of increased process
understanding and optimization was demonstrated
