Low energy resonance vibration submerged membrane system for microalgae harvesting: Performance and feasibility

• Published in: Desalination 2022-10, Vol.539, p.115895, Article 115895
• Main Authors: Min, Choongsik, Kim, Jung Eun, Shon, Ho Kyong, Kim, Seung-Hyun
• Format: Article
• Language: English
• Subjects: Energy saving; Fouling mitigation; Intermittent relaxation; Microalgae harvesting; Resonance vibration system
• ISSN: 0011-9164; 1873-4464
• DOI: 10.1016/j.desal.2022.115895

This study investigated an energy-efficient harvesting method to collect microalgae of Chlorella Vulgaris (C. vulgaris). The method proposed in the current study was a combination of a resonance vibration submerged membrane (RVSM) system and centrifugation. The result showed that the RVSM system was able to concentrate the C. vulgaris solution by 17 times (0.61 g·L−1 to 10.4 g·L−1) without chemical cleaning during filtration with intermittent relaxation (i.e., filtration for 9 min and relaxation for 1 min) at a flux of 40 LMH (L·m−2·h−1) until the transmembrane pressure (TMP) reached 70 kPa. In addition, extracellular polymeric substances such as polysaccharides and protein were found mainly responsible for membrane fouling during the operation of concentrating C. vulgaris solution. Integrating the RVSM system with the centrifugation process required the total specific energy consumption of 0.56 kWh·m−3 (0.09 kWh·m−3 for the RVSM and 0.47 kWh·m−3 for the centrifugation). This study demonstrated the combination of the RVSM system and centrifugation to be a feasible C. vulgaris harvesting method by showing lower energy consumption than other conventional processes. •Resonance vibration submerged membrane (RVSM) had a low membrane fouling.•RVSM system showed twice as high as the critical flux of 45 LMH.•RVSM system concentrated the C. vulgaris solution by 17 times.•Combining the RVSM system and centrifugation consumed the energy of 0.56 kWh·m−3.