Sewage wastewater reclamation with sand column filter and reduction of heavy metal accumulation in tomato and okra

Abstract

Heavy metal accumulation has much increased in edible parts of fresh fruits and vegetables due to use of industrial waste/effluent, and wastewater. In the current work, sewage wastewater was reclaimed through a column filled with sand having a mesh size of 0.5 mm and its effect was investigated on concentration of different heavy metals, vegetative growth, and yield of okra and tomato. The use of unfiltered sewage wastewater (UFSW) had considerably higher concentrations of heavy metals but it substantially increased plant height, leaf number, and leaf area in both okra and tomato plants in contrast to filtered sewage wastewater (FSW). The application of UFSW resulted in a significantly higher accumulation of lead (Pb), nickel (Ni), iron (Fe), and copper (Cu) in roots and edible parts of okra and tomato as compared with FSW treatment. However, FSW and UFSW did not significantly influence concentrations of chromium (Cr) and cadmium (Cd) in roots and edible parts of both okra and tomato. In conclusion, sand column filtration technique could be efficiently used for the reclamation of sewage wastewater, and reduction of various heavy metals present in sewage wastewater-irrigated crops.

Keywords: Growth; Heavy metals; Okra; Sand column; Sewage water; Tomato.