The use of Bassia indica for salt phytoremediation in constructed wetlands

The treatment and reuse of wastewater in constructed wetlands offers a low-cost, environmentally-friendly alternative for common engineered systems. Salinity in treated wastewater is often increased, especially in arid and semi-arid areas, and may harm crops irrigated from wetlands. We have strong evidence that halophyte plants are able to reduce the salinity of wastewater by accumulating salts in their tissues. Bassia indica is an annual halophyte with unique adaptations for salt tolerance. We performed three experiments to evaluate the capability of B. indica for salt phytoremediation as follows: a hydroponic system with mixed salt solutions, a recirculated vertical flow constructed wetland (RVFCW) with domestic wastewater, and a vertical flow constructed wetland (VFCW) for treating goat farm effluents. B. Indica plants developed successfully in all three systems and reduced the effluent salinity by 20–60% in comparison with unplanted systems or systems planted with other wetland plants. Salinity reduction was attributed to the accumulation of salts, mainly Na and K, in the leaves. Our experiments were carried out on an operative scale, suggesting a novel treatment for green desalination in constructed wetlands by salt phytoremediation in desert regions and other ecosystems.

Salt phytoremediation by Bassia indica is demonstrated as the percent EC change in a recirculating vertical flow constructed wetland (RVFCW) effluent as compared with the EC change in unplanted RVFCW (control). Daily global sun radiation on the sampling days is given in the upper graph in MJ/m2.Figure optionsDownload high-quality image (141 K)Download as PowerPoint slideHighlights
► Reused wastewater is an important water resource, but is often saline as compared with fresh water.
► The use of the halophyte shrub Bassia indica for salt phytoremediation was found to be efficient.
► B. indica reduced the total salinity by accumulating salts in its leaves.