The use of Bassia indica for salt phytoremediation in constructed wetlands

Abstract

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.