A one-dimensional reactive transport model of geochemical desalination scaling




Freiburger, Andrew P.
Molins, Sergi
Buckley, Heather L.

Journal Title

Journal ISSN

Volume Title




Freshwater insecurity afflicts billions of people each year, yet desalination technologies such as Reverse osmosis (RO) can sustainably purify ocean water into a limitless source of potable water. The economical efficiency of RO, however, hinders its practicality. Mineral nucleation on the membrane surface in a process called scaling is specifi cally problematic for RO modules, but the geochemical mechanisms of scaling (particularly from brackish feed waters) remain elusive to experimental protocols and most simulations of RO systems. We therefore developed a geochemical reactive transport model of RO desalination that simulates one dimension of the feed-membrane interface while resolving the mineral geochemistry that manifests in scaling via robust PHREEQC calculations. This approach balances computational expense and with sufficiently precise results for actionable interpretation. Our model is implemented as an operable Python Software (ROSSpy) that provides users spatiotemporal predictions of scale deposits and concentration changes through the model as a function of specifi ed feed concentrations and conditions, and the RO module specifi cations. The raw output is additionally visualized to facilitate user interpretation. We exemplify this model through numerous case studies and parameter scans. This concise yet rigorous model provides a unique tool to identify appealing feed waters and to improve RO designs towards developing sustainable water systems in diverse conditions around the world.


The authors thank Ethan Sean Chan for his technical assistance in developing a forthcoming interactive version of ROSSpy (iROSSpy). The authors additionally thank Nusret Ipek, Min Yang, and Lixuan An for invaluable feedback that improved the accessibility of ROSSpy software.


Reverse Osmosis, desalination, geochemistry, reactive transport, scaling


Freiburger, A. P., Molins, S., & Buckley, H. L. (2023). A one-dimensional reactive transport model of geochemical desalination scaling. SSRN. https://dx.doi.org/10.2139/ssrn.4124149