Phytoremediation of Boron From Wastewater in Vertical Flow Constructed Wetlands

Abstract

The aim of this work was to evaluate the possibility of boron removal from synthetic wastewater using a vertical constructed flow (VFCW) planted with Vetiveria zizanioides. Two boron concentrations were used (15 ± 1 and 30 ± 1 mg L−1) and a hydraulic load (HL) of 191 ± 10 L m−2d−1. The wastewater samples were taken and the flow rate in the inlet and outlet of the VFCW were measured. The levels of dissolved oxygen, electrical conductivity, pH and boron were determined in the wastewater. The concentrations of the essential elements and nutrients, namely total Kjeldhal nitrogen, phosphorus, calcium, magnesium, sodium and potassium in above growth biomass composition were measured. The results showed that: boron removal efficiencies depended on the boron concentration, so 60 ± 3% was obtained for the 15 mg L−1 concentration and 26 ± 2% for 30 mg L−1; calcium, magnesium, potassium and sodium concentrations in the vegetal biomass decreased to the boron concentration of 30 mg L−1, and boron may have interfered with Vetiveria zizanioides growth. Keywords: biomass composition, boron removal, light expanded clay aggregates, Vetiveria zizanioides, vertical flow constructed wetland