Maano Tshimange
About
My research project
Mining of phosphorus in wastewater using forward-osmosis membrane systemPhosphorus (P) is widely used in agriculture as a fertiliser. Contrastingly, when P present in municipal wastewater (MW) is discharged into freshwater bodies, it becomes a contaminant, deteriorating the water quality. If we could recover P from MW, it would be possible to reduce P impact in receiving waters and simultaneously produce valuable P-fertilizers that can be reused in agriculture. Forward-Osmosis (FO) membrane is becoming a promising technology to recover P since it is inexpensive, environmentally friendly and energy-efficient. Although there are many studies on FO in wastewater, there is little information on the purification of the final P-recovered product.
Therefore, my research project aims to evaluate the P-recovery potential by FO and the purification of the final Phosphorus-product. This project will involve various laboratory approaches. The results of this study will provide important information on final P-product purification that will contribute to commercializing of FO in recovering P from MW.
Supervisors
Phosphorus (P) is widely used in agriculture as a fertiliser. Contrastingly, when P present in municipal wastewater (MW) is discharged into freshwater bodies, it becomes a contaminant, deteriorating the water quality. If we could recover P from MW, it would be possible to reduce P impact in receiving waters and simultaneously produce valuable P-fertilizers that can be reused in agriculture. Forward-Osmosis (FO) membrane is becoming a promising technology to recover P since it is inexpensive, environmentally friendly and energy-efficient. Although there are many studies on FO in wastewater, there is little information on the purification of the final P-recovered product.
Therefore, my research project aims to evaluate the P-recovery potential by FO and the purification of the final Phosphorus-product. This project will involve various laboratory approaches. The results of this study will provide important information on final P-product purification that will contribute to commercializing of FO in recovering P from MW.
Publications
Highlights • FHU prefiltration cut FO flux decline to 37% vs 60% UHU • Proteinaceous biofouling dominated, bacteria vs yeast by urine pH • Sequential cleaning restored 91-98% flux despite residual organics • RSF from 5 M NaCl increased Na⁺ 4.8x VCF in concentrates • Particulates + chemistry control FO fouling reversibility Abstract Forward osmosis (FO) enables efficient human urine concentration for nutrient recovery, but fouling hinders implementation. This study investigated multi-cycle FO fouling with real urine: filtered hydrolysed (FHU), unfiltered hydrolysed (UHU), and citric-acid-stabilised urine (SU, pH ≈ 5). FHU showed lower flux decline (37%) due to particulate removal, while UHU suffered severe fouling (60% loss, 43% recovery) and SU exhibited intermediate behaviour. Membranes rejected ≥90–95% of PO₄³⁻, Ca²⁺, Mg²⁺, and COD, with moderate K⁺/NH₄⁺ passage. Membrane autopsy revealed biofouling dominance: rod/cocci bacteria in alkaline FHU/UHU, yeast-like structures in SU, with minimal inorganic scaling. Sequential physical–chemical cleaning restored 91–98% of flux, although residual foulants indicated partially irreversible fouling. Reverse salt flux from 5 M NaCl increased concentrate salinity. Overall, this research provides valuable insights into the fouling mechanisms within FO caused 2