Simultaneous phosphorous and nitrogen recovery from source-separated urine: A novel application for fertiliser drawn forward osmosis. (July 2018)

• Record Type: Journal Article
• Authors: Volpin, Federico; Chekli, Laura; Phuntsho, Sherub; Cho, Jaeweon; Ghaffour, Noreddine; Vrouwenvelder, Johannes S.; Kyong Shon, Ho
• Is Part Of: Chemosphere. Volume 203(2018)
• Page Start: 482
• Page End: 489
• Publication Date: 2018-07
• Subjects: Forward osmosis -- Urine treatment -- Phosphorous recovery -- Nitrogen recovery -- Fertiliser draw solution; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2018.03.193
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Re-thinking our approach to dealing with waste is one of the major challenges in achieving a more sustainable society. However, it could also generate numerous opportunities. Specifically, in the context of wastewater, nutrients, energy and water could be mined from it. Because of its exceptionally high nitrogen (N) and phosphorous (P) concentration, human urine is particularly suitable to be processed for fertiliser production. In the present study, forward osmosis (FO) was employed to mine the P and N from human urine. Two Mg 2+ -fertilisers, i.e. MgSO4 and Mg(NO3 )2 were selected as draw solution (DS) to dewater synthetic non-hydrolysed urine. In this process, the Mg 2+ reverse salt flux (RSF) were used to recover P as struvite. Simultaneously, the urea was recovered in the DS as it is poorly rejected by the FO membrane. The results showed that, after concentrating the urine by 60%, about 40% of the P and 50% of the N were recovered. XRD and SEM – EDX analysis confirmed that P was precipitated as mineral struvite. If successfully tested on real urine, this process could be applied to treat the urine collected in urban areas e.g., high-rise building. After the filtration, the solid struvite could be sold for inland applications whereas the diluted fertiliser used for direct fertigation of green walls, parks or for urban farming. Finally, reduction in the load of N, P to the downstream wastewater treatment plant would also ensure a more sustainable urban water cycle. Graphical abstract: Highlights: FDFO could be used for simultaneous urine dewatering, urea and phosphorous recovery. About 50% of the nitrogen and 40% of the phosphorous were recovered while 60% of urine concentration was reached. Phosphorous precipitated as mineral struvite.