Evaluation of Heavy Metal Removal Efficiency of Azolla filiculoides and Lemna minor in Tertiary Institution Referral Hospital Effluent at Hawassa City, Ethiopia

Abstract

Healthcare wastewater discharged without proper treatment is an emerging environmental issue. Existing wastewater treatment technologies for the remediation of heavy metals are costly, time consuming, and don‟t provide a satisfactory solution. Therefore, the objective of this paper was to investigate the heavy metal removal efficiency of Azolla filiculoides and Lemna minor for six heavy metals (Cr, Co, Ni, Zn, Cd, and Pb) from a tertiary institution referral hospital effluent at Hawassa City, Ethiopia, using appropriate standard procedures. The average heavy metal concentrations in both macrophyte treatments were as follows: Zn > Ni > Co > Cr > Pb > Cd. ANOVA showed significant differences (p < 0.05) between the two macrophytes in removing all evaluated factors. The maximum removal was revealed for Zn (98.35%) by L. minor compared to A. filiculoides (94.13%). The BCF values for L. minor and A. filiculoides were in the following order: Cd > Pb > Zn > Co > Ni > Cr and Cd > Pb > Zn > Cr > Co > Ni, respectively. Finally, both macrophytes were effective phytoremediation choices for the treatment of hospital effluent.