Study on micro-nanobubble control of membrane fouling in vacuum membrane distillation of high salt organic wastewater

In order to explore the contribution of organics and salts to membrane fouling and the control effect of micro-nanobubbles on different types of membrane fouling in the treatment of high salt wastewater by vacuum membrane distillation, three typical organic pollutants, humic acid, bovine serum protein and sodium alginate, were selected to investigate the influence of single organic matter, the coexistence of organic matter and salt on membrane pollution and the control effect of micro-nanobubble aeration on membrane pollution. The results showed that the membrane pollution caused by sodium alginate was the most serious among the three organic compounds. When the sodium alginate concentration was 100 mg/L, the relative membrane flux decreased to 67.07% after 7 h of vacuum membrane distillation system operation. When the humic acid concentration of feed solution was 10, 50 and 100 mg/L, the relative membrane flux decreased to 36.33%, 33.15% and 20.59%, respectively, after 7 h of system operation. When three organic compounds coexisted with salt, the membrane pollution was worse than that when single organic compound coexisted with salt. Micro-nanobubbles could effectively control the compound pollution caused by organic-salt coexistence in vacuum membrane distillation system.