Simultaneous Bioremediation of Cyanide, Phenol, and Ammoniacal-N from Synthetic Coke-Oven Wastewater Using <i>Bacillus</i> sp. NITD 19

Abstract

Coke-oven wastewater is generally characterized by having an array of pollutants such as cyanide, phenol, and ammoniacal-N. The present study focuses on the simultaneous removal of such pollutants from synthetic coke-oven wastewater using a bacterial isolate, Bacillus sp. NITD 19, collected from the contaminated site. Growth of bacterial sample was studied in Luria–Bertani (LB) medium. The tolerance limit of each pollutant was studied with the bacterial strain. One variable at a time (OVAT) approach was followed to see the individual effect of operating factors on the removal of each pollutant. Effective conditions like pH (8); inoculum size (IS) (4%); and initial concentrations of phenol (100 mg/L), cyanide (40 mg/L), and ammoniacal-N (400 mg/L) were ascertained after OVAT analysis. Synthetic coke-oven wastewater (SCW) was prepared by mixing these three pollutants at their most effective initial concentrations. The time variation for removal of pollutants from individual aqueous solutions and SCW was studied at the most effective condition with the bacterial strain. Maximum removal of phenol (79.88%±1.3%, 72.84%±1.21%), ammoniacal-N (82.83%±1.23%, 80.25%±1.49%), and cyanide (89.51%±1.44%, 79.78%±0.95%) were obtained from individual aqueous solution and SCW, respectively. Biomass extracted from the SCW solution was less than that obtained after the treatment of individual pollutants. Fourier-transform infrared spectrophotometry (FTIR) study and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis were performed for native and treated bacterial strain.