An Innovative Solar-Driven Thermo-hydraulic Ultrafiltration Process. Part I: Hydraulic Experiments and Modeling

Ultrafiltration technology is an easy-to-implement, energy-efficient, and selective disinfection method for a wide range of pollutants that can facilitate access to drinking water, one of the major worldwide challenges of this century. The work presented here is the first part of a study investigating an innovative thermo-hydraulic ultrafiltration process. The process is powered by solar thermal energy supplied at 40–70 °C by a simple flat-plate solar collector to pump and pressurize the water to be treated by an ultrafiltration module. The preliminary experimental study carried out and presented in this paper has enabled the characterization of the hydraulic pumping/pressurization devices with an energy efficiency ranging from 0.9 to 0.75. The backwashing device ensured a pressure ratio between the filtration and backwashing, varying between 0.85 and 1.1. A series of 30 min filtration of river water taken downstream of a wastewater treatment plant, carried out at a transmembrane pressure of 1.5 bar and followed by a 3 min backwash, made it possible to achieve a stabilization of the membrane permeability between 70 and 80% of its initial permeability. An unsteady-state numerical model was developed to simulate and analyze the behavior of the process in filtration mode and during backwashing. The average deviations that were observed between simulated and experimental results amounted to 6.4% for flow rates and 1.6% for pressures.