A novel salt-tolerant bacterial consortium for biodegradation of saline and recalcitrant petrochemical wastewater

Treatment of a saline petrochemical wastewater with BOD5/COD ratio of less than 0.1 was investigated using a consortium consisted of three isolated salt-tolerant bacteria namely, Kocuria turfanesis, Halomonas alkaliphila and Pseudomonas balearica. Selected bacteria were isolated from petrochemical wastewater containing mineral salt mediums of 3% salinity. A lab-scale activated sludge bioreactor was used for startup in batch mode operation and after obtaining the MLSS concentration of about 3000 mg/L, the operation was changed to continuous flow mode to determine the biokinetic coefficients under different organic loading rates of 0.33-1.21 kg CODm(-3) d(-1). The COD removal efficiency of 78.7%-61.5% was observed for treatment of real saline wastewater with a decreasing trend along with increasing the organic loading rate. In addition, results of kinetic investigation demonstrated that the yield(Y), endogenous decay coefficient (K-d), maximum reaction rate (K-max), maximum specific growth rate (mu(max)) and saturation constant (K-s) were 0.54 mg VSS mg COD-1, 0.014 day(-1), 1.23 day(-1), 0.66 day(-1), and 1315 mg 171, respectively. (C) 2017 Elsevier Ltd. All rights reserved.