title: Enhanced hydrolysis and acidification of waste activated sludge by biosurfactant rhamnolipid.
abstract: The effect of biosurfactant rhamnolipid (RL) on hydrolysis and acidification of waste activated sludge (WAS) was investigated. The results indicated that RL could greatly reduce the surface tension of sludge, resulting in stimulating the hydrolysis rate of WAS and enhancing the production of short-chain fatty acids (SCFAs). With the increase of RL dosage from 0.2 to 0.5 g/g DS, the maximum soluble chemical oxygen demand (SCOD), protein and carbohydrate concentration increased correspondingly. After 6 h of hydrolysis, SCOD, protein and carbohydrate concentration increased from 371.9, 93.3 and 9.0 mg/l to 3,994.5, 800.0 and 401.4 mg/l at RL 0.3 g/g DS, respectively. Furthermore, the release of NH4 (+)-N, PO4 (3-)-P and the accumulation of SCFAs also improved in the presence of RL. The maximum SCFAs was 1,829.9 mg COD/l at RL 0.3 g/g DS, while it was only 377.7 mg COD/l for the blank test. The propionic acid and acetic acid were the mainly SCFAs produced, accounting for 50-60% of total SCFAs.
authors: College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China.
authors: Xin
authors: X
authors: Yi
authors: Kun
authors: K
authors: Luo
authors: Qi
authors: Q
authors: Yang
authors: Xiao-Ming
authors: XM
authors: Li
authors: Wei-Guang
authors: WG
authors: Deng
authors: Hong-Bo
authors: HB
authors: Cheng
authors: Zi-long
authors: ZL
authors: Wang
authors: Guang-Ming
authors: GM
authors: Zeng
mesh_terms: D005232:Fatty Acids, Volatile / Q000737:chemistry; D006017:Glycolipids / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D012722:Sewage / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry*
chemical_list: D005232:Fatty Acids, Volatile; D006017:Glycolipids; D012722:Sewage; D013501:Surface-Active Agents; C418382:rhamnolipid