Harvesting microalgal biomass using submerged microfiltration membranes

• DOI: 10.1016/j.biortech.2012.02.009
• Publication Date: 2012-02-14T08:16:15Z
• Authors: M.R. Bilad; D. Vandamme; I. Foubert; K. Muylaert; Ivo F.J. Vankelecom
• Keywords: Microalgae; Spectrometry, X-Ray Emission; Membranes, Artificial; Biomass; 01 natural sciences; Filtration; 6. Clean water; 0105 earth and related environmental sciences

This study was performed to investigate the applicability of submerged microfiltration as a first step of up-concentration for harvesting both a freshwater green algae species Chlorella vulgaris and a marine diatom Phaeodactylum tricornutum using three lab-made membranes with different porosity. The filtration performance was assessed by conducting the improved flux step method (IFM) and batch up-concentration filtrations. The fouling autopsy of the membranes was performed by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and Fourier transform infrared spectroscopy (FTIR). The cost analysis was estimated based on the data of a related full-scale submerged membrane bioreactor (MBR). Overall results suggest that submerged microfiltration for algal harvesting is economically feasible. The IFM results indicate a low degree of fouling, comparable to the one obtained for a submerged MBR. By combining the submerged microfiltration with centrifugation to reach a final concentration of 22% w/v, the energy consumption to dewater C. vulgaris and P. tricornutum is 0.84 kW h/m(3) and 0.91 kW h/m(3), respectively.