Anaerobic treatment of saline wastewater by Halanaerobium lacusrosei

Abstract

An upflow anaerobic packed bed reactor was operated continuously with synthetic saline wastewater at different initial COD concentrations (COD 0 = 1900–6300 mg/L), salt concentrations (0–5%, w/v) and hydraulic retention times ( θ H = 11–30 h) to investigate the effect of those operating parameters on COD removal from saline synthetic wastewater. Anaerobic salt tolerant bacteria, Halanaerobium lacusrosei, were used as dominant microbial culture in the process. The percent COD removal reached up to 94% at COD 0 = 1900 mg/L, 19 h hydraulic retention time and 3% salt concentration. No substrate inhibition effect was observed at high feed CODs. Increasing hydraulic retention time from 11 h to 30 h resulted in a substantial improvement in the COD removal from 60% to 84% at around COD 0 = 3400 mg/L and 3% salt concentration. Salt inhibition effect on COD utilization was observed at above 3% salt concentration. Modified Stover–Kincannon model was applied to the experimental data to determine the biokinetic coefficients. Saturation value constant, and maximum utilization rate constant of Stover–Kincannon model for COD were determined as K B = 5.3 g/L day, U max = 7.05 g/L day, respectively.