ABSTRACT
A project to store rainwater in an underground reservoir has been designed for a loess plateau, in which rainwater is to be collected from road surfaces prior to infiltration into a buried riverbed that extends parallel to a road. Consequently, the rainwater recharge into the buried riverbed would form an unconfined aquifer. Some 55 different organic pollutants at trace level were identified by the analysis of rainwater collected from road surfaces. To improve the rainwater quality for recharge, a purification measure is taken by modifying the overlying soils with surfactants. Both cationic surfactant hexadecyltrim- ethylammonium bromide (HDTMA-Br) and anionic surfactant sodium dodethylbenzene sulfonate (SDBS) were used to modify the loess soils. The approach can enhance soil sorption capabilities by 2–10 times, as a result, leachates of petroleum contaminants would be held up within the topsoil. The sorption of organic contaminants on the modified soils can be characterized by linear isotherms. Taking toluene as the indicator of organic contaminants, Partition and adsorption contributions to the sorption amount are determined quantitatively.
