Optimum scaling relation for dynamic shear enhanced membrane filtration pilots in nutrient and mineral recovery from wastewater

Recovery of nutrients and minerals from wastewater by membrane filtration holds promise for sustainable water processing. While dealing with such processes that often result in substantial filtrate throughput decline due to membrane fouling, Dynamic Shear Enhanced Membrane Filtration Pilots (DSEMFPs) have proven to be an ideal contender. These devices generate feed flow-independent shear that triggers solute back-transport away from the membrane. Subsequent flux enhancement is a congruous merit. Power-law correlation between the flux and average shear rate has been so extensively used in several studies so that it became the ubiquitous scaling relation for DSEMFPs. However, in this article, we have demonstrated a novel and more expansive scaling between flux and a set of prototypical turbulent measures (i.e., turbulent kinetic energy, kinetic energy dissipation rate, and Kolmogorov scale), relative to shear rate, ranging over five different DSEMFPs. Flux data were collected from previous studies, whereas hydrodynamic variables were evaluated computationally. All turbulent measures exhibited better correlation compared to shear rate with the Kolmogorov scale being the best regressor (R² > 0.96). The study demonstrates that turbulence has an equivalent, if not superior, role in upscaling flux in DSEMFPs against the conventional idea of shear generation being primary.