Insights into the Effect of Rhamnolipids on the Anaerobic Fermentation and Microalgae Lipid Production of Waste Activated Sludge: Performance and Mechanisms

In the last few years, production of waste activated sludge (WAS) has increased dramatically, and treatment disposal have attracted widespread attention. this study, rhamnolipids were used to improve efficiency hydrogen from WAS, fermentation solution was as a substrate by lipid-producing microalgae recover resources generate clean energy. Results showed that had best effect among several surfactants in promoting production, WAS added with 0.4 g/g TS reached 178.48 ± 6.07 mL/g TS, which improved 13.53 times compared control group. The content SCOD, soluble protein, polysaccharide addition rhamnolipid 9.19, 11.46, 42.28 times, respectively, indicating could hydrolysis led an increase production. And three-dimensional excitation–emission matrix fluorescence spectroscopic analysis intensity dissolved organic matter increased, suggesting rise microbial metabolites. composition volatile fatty acids type mainly butyric acid-type high concentrations n-butyric acid (9330.14 525.33 mg/L) acetic (6324.07 80.67 mg/L). addition, community structure system dominant genus Clostridium sensu stricto. Microalgae can utilize acid, ethanol, NH4+-N, PO43–-P, proteins, polysaccharides grow produce lipids. biomass lipid productivity cultured 3.16 0.58 g/L 356.86 4.91 mg/L/day, respectively. contained 84.57 4.33% saturated content, more favorable for biodiesel This study not only successfully utilized promote but also coupled system, further laying foundation realizing resource utilization energy