The biodegradability of some anionic surfactants in the river die-away test was studied. The biodegradability was evaluated by the methylene blue activity and total organic carbon (TOC). Sodium α-olefin sulfonate (AOS), sodium n-dodecyl sulfate (SDS), sodium polyoxyethylene glycol n-dodecyl ether sulfate (DES), sodium linear alkylbenzene sulfonate (LAS), sodium branched alkylbenzene sulfonate (ABS) and sodium stearate (Soap) were used as test material in this study.
It was observed that these surfactants, except ABS, were biodegraded intoneinorganic substances in this experimental period. The relative biodegradation rate, estimated by methylene blue activity was SDS_??_DES>AOS>LAS>>ABS, and estimated by TOC was Soap_??_SDS_??_AOS>DES>LAS>>ABS. The methylene blue activity was disappeared in shorter period than TOC.