An interval steady-state multimedia aquivalence (ISMA) model of the transport and fate of chloridion in a surface flow constructed wetland system treating oilfield wastewater in China

► Treatment of oilfield wastewater by a surface flow constructed wetland system. ► Development of an interval steady-state multimedia aquivalence (ISMA) model. ► Simulation of Cl− transport and fate in the multimedia environments. ► Restoration of local ecological environment by wastewater irrigation. A surface flow constructed wetland (SFCW) system was built up to treat oilfield wastewater after secondary treatment. Chloridion (Cl−) in the wastewater was selected as an indicator to investigate the transport and fate of inorganic salts at high levels in the multimedia environments (air, water, soil, flora, and groundwater) by developing an interval steady-state multimedia aquivalence (ISMA) model. The modeled Cl− profiles were in good agreement with the measured ones, as indicated by the interval average logarithmic residual errors (IALREs) (