Purification of Sewage Wastewater though Sand Column Filter for Lessening of Heavy Metals Accumulation in Lettuce, Carrot, and Cauliflower

Abstract

Sewage wastewater is one of the richest sources of mineral nutrients contributing toward plant growth and yield. However, the accumulation of heavy metals in the edible parts of vegetables and fruits can be dangerous to life. The current research aimed to evaluate the performance of a sand column filter for the elimination of heavy metals from sewage wastewater applied to selected vegetables. The contents of heavy metals, i.e., Pb+2, Ni+2, Cu+2, and Fe+2, were estimated to be higher in untreated sewage wastewater than in treated water. The number of leaves, fresh and dry weights of leaves, roots, and total biomass of lettuce, carrot, and cauliflower were improved due to the irrigation of unfiltered sewage wastewater compared to sewage wastewater. The curd diameter, fresh and dry weights of curd, stem fresh weight of cauliflower, and the root length and diameter of carrot increased after irrigation with the unfiltered sewage wastewater in comparison to the treated sewage wastewater. The accumulation of heavy metals, i.e., Pb+2, Ni+2, Cu+2, and Fe+2, was higher in the roots, leaves, and edible parts of the selected vegetables. In the present study, the Cd+2 and Cr+2 concentrations were not affected by the filtration process through a sand column filter. Conclusively, filtration through a sand column filter is effective for the removal of heavy metals from sewage wastewater used to irrigate agricultural land.