Phytotoxicity test of Scirpus grossus on diesel-contaminated water using a subsurface flow system

A phytotoxicity experiment with diesel as a model hydrocarbon pollutant at different concentrations (0, 8700, 17,400 and 26,100 mg/L) was performed on the emergent wetland bulrush of Scirpus grossus in a subsurface flow system (SSF). After 72 days of exposure, maximum removal occurred at the diesel concentration of 17,400 mg/L at 91.5%; in the corresponding control without plants, the removal was only 54.1%. Furthermore, the removal efficiency of hydrocarbons from sand was determined to be in the range of 67.2–69.9% for all treatments. According to the plant growth parameters, it was shown that S. grossus could effectively promote the degradation of total petroleum hydrocarbons (TPH) when the concentration of diesel in water was up to17,400 mg/L. The population of living microorganisms in the planted aquariums could also adapt to ≤17,400 mg/L diesel contaminated water. This study showed that S. grossus and rhizobacteria in a subsurface flow system has potential in reclaiming hydrocarbon-contaminated water.

► Scirpus grossus can enhance the rhizobacteria to degrade hydrocarbon.
► High degradation efficiency of hydrocarbons from water as 91.5% for 17,400 mg/L.
► Growth of microorganisms in S. grossus rhizosphere was enhanced with diesel.
► Plant growth observed to increase in 8700 and 17,400 mg/L diesel concentrations.