Air bubbling assisted solar-driven submerged vacuum membrane distillation for aquaculture seawater desalination

Submerged vacuum membrane distillation (S-VMD) was proposed in this work to desalinate aquaculture seawater. In this S-VMD without feed-pumping system, the hydrophobic hollow fibre membranes are fully immersed in the feed tank with internal coil heated by solar evacuated tube collector. In this study, indoor test under steady-state condition was compared to the outdoor test under solar intensity variation. The system's feasibility and practicality were investigated. In the daily outdoor performance test, the solar-powered S-VMD system obtained permeate flux at 2.1–5.2 kg/m²h, depending on the solar intensity profile. Air bubbling as enhanced flow promoter and anti-fouling technique was employed to overcome the polarizations at the membrane boundary layer. Compared to non-bubbling, the bubbling approach in the S-VMD system effectively achieved higher flux and fouling reduction with better permeate quality. It is suggested that the system can be applied in energy-deprived and space-constricted remote area, particularly marine aquaculture farm to produce clean water for coastal fishery communities.