Virus rejection and removal in pilot-scale air-gap membrane distillation

• Published in: Water research (Oxford) Vol. 240; p. 120019
• Main Authors: Hardikar, Mukta, Felix, Varinia, Rabe, Andrew B., Ikner, Luisa A., Hickenbottom, Kerri L., Achilli, Andrea
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 15.07.2023
• Subjects: Concentrate management; Membrane distillation; Pilot-scale; Potable water reuse; Reverse osmosis concentrate; Virus rejection; Potable water reuse; Reverse osmosis concentrate; Concentrate management; Pilot-scale; Membrane distillation; Virus rejection
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2023.120019

•Rejection of MS2 and PhiX174 was quantified in a pilot-scale air-gap membrane distillation system.•MS2 and PhiX174 were both detected in the distillate.•Virus rejection was higher than inorganic and organic solute rejection.•Thermal virus inactivation rate was lower in pilot-scale compared to bench-top tests. Membrane distillation (MD) is a thermally-driven process that can treat high concentration streams and provide a dual barrier for rejection and reduction of pathogens. Thus, MD has potential applications in treating concentrated wastewater brines for enhancing water recovery and potable water reuse. In bench-scale studies, it was demonstrated that MD can provide high rejection of MS2 and PhiX174 bacteriophage viruses, and when operating at temperatures greater than 55 °C, can reduce virus levels in the concentrate. However, bench-scale MD results cannot directly be used to predict pilot-scale contaminant rejection and removal of viruses because of the lower water flux and higher transmembrane hydraulic pressure difference in pilot-scale systems. Thus far, virus rejection and removal have not been quantified in pilot-scale MD systems. In this work, the rejection of MS2 and PhiX174 at low (40 °C) and high (70 °C) inlet temperatures is quantified in a pilot-scale air-gap MD system using tertiary treated wastewater. Both viruses were detected in the distillate which suggests the presence of pore flow; the virus rejection at a hot inlet temperature of 40 °C for MS2 and PhiX174 were 1.6-log10 and 3.1-log10, respectively. At 70 °C, virus concentrations in the brine decreased and were below the detection limit (1 PFU per 100 mL) after 4.5 h, however, viruses were also detected in the distillate in that duration. Results demonstrate that virus rejection is lower in pilot-scale experiments because of increased pore flow that is not captured in bench-scale experiments. [Display omitted]