Abstract: A slow-release aeration biomembrane made from fiber media unit was used to dispose benzene, toluene, ethylbenzene, and xylene (BTEX) pollution in the river caused by accidental release from a chemical plant.The slow-release aeration biomembrane system was developed to treat wastewater containing BTEX effectively, when the bioreacter was inoculated with co-culture of pure microorganism and recycled with a medium content of BTEX. The biomembrane system showed good performance after 30 days of start-up period. At a high BTEX concentration in the river, the fiber media unit could effect adsorption treatment due to its tremendous specific surface. When the original BTEX concentration was 50—100 mg/L, it could drop to below 5 mg/L after 24 h of disposal. When the BTEX concentration was low in the water, the microbe in the slowly-released aeration biomembrane could effect biodegredation. When the initial BTEX concentration in the water was between 0.5—1.5 mg/L , the removal rate of BTEX could reach above 90% after 15 days of disposal.