Development, implementation, and validation of a generic nutrient recovery model (NRM) library

• Published in: Environmental modelling & software : with environment data news Vol. 99; pp. 170 - 209
• Main Authors: Vaneeckhaute, C., Claeys, F.H.A., Tack, F.M.G., Meers, E., Belia, E., Vanrolleghem, P.A.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.01.2018; Elsevier Science Ltd
• Subjects: Anaerobic digestion model; Anaerobic processes; Chemical precipitation; Computer simulation; Crystallization; Data bases; Fertilizers; Generic physicochemical model framework; Kinetics; Mathematical modelling; Mathematical models; Numerical solution; Nutrients; Optimization; Precipitation; Reaction kinetics; Recovery; Reduced PHREEQC; Resource recovery; Speciation; Washing; Water chemistry; Resource recovery; Water chemistry; Generic physicochemical model framework; Numerical solution; Mathematical modelling; Anaerobic digestion model; Reduced PHREEQC
• ISSN: 1364-8152; 1873-6726
• DOI: 10.1016/j.envsoft.2017.09.002

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. [Display omitted] •The first generic nutrient recovery model library was developed and implemented.•An efficient numerical solution strategy was established through model coupling.•Implementation correctness was verified using a 6-step procedure.•Steady-state simulation results showed excellent agreement with experimental results.•The models were applied as tool for increased process understanding & optimization.