TANNERY WASTEWATER REMEDIATION COMPETENCE OF METAL TOLERANT BACTERIA AND FUNGI UNDER THE INFLUENCE OF CHEMICALLY MODIFIED WATER HYACINTH BIOCHAR: AN IN VITRO EVALUATION

Abstract

This study was trying to find a sustainable approach to remediate the tannery wastewater by various treatments sets (set-I to set-VIII: consists of KOH modified biochar, Bacillus cereus, and Aspergillus flavus biomass), and treatment successfulness was determined by phytotoxicity and cytotoxicity studies on potential Vigna unguiculata seedlings and Artemia franciscana larvae, respectively. Three tannery wastewater samples were collected from 3 sites (I, II, and III); among them, the physicochemical properties of site I were beyond the permissible limits containing more volume of harmful heavy metals such as Cr, Cd, Pb, As, Co, Cu, Fe, Zn, and Mn than other sample. The test B. cereus and A. flavus showed remarkable metal tolerance to heavy metals such as Cr, Cd, Pb, As, Co, Cu, Fe, Zn, and Mn at 800 µg mL−1. The bioremediation study results stated that the KOH modified pre-synthesized and characterized water hyacinth biochar with the blend of B. cereus and A. flavus (treatment set-VII) biomass substantially reduced/removed (Cr, Cd, Pd, As, Co, Cu, Fe, Zn, and Mn as 54.75%, 49.52%, 30.49%, 17.53%, 29.07%, 14.75%, 5%, 27.27%, and 9.2%, respectively) the heavy metals from the tannery wastewater. The treatment effectiveness was determined by phytotoxicity and cytotoxicity studies on V. unguiculata seedlings and A. franciscana larvae, respectively. Among various treatment sets, the set-VII demonstrated absence of phytotoxicity and cytotoxicity on V. unguiculata seedlings and A. franciscana larvae, respectively. This clearly shows that the KOH modified biochar with B. cereus and A. flavus biomass can be used to manage and treat tannery wastewater in a sustainable manner.