Continuous operation of anaerobic packed bed reactor for cod removal from saline wastewater

The treatibility of saline wastewater under anaerobic conditions with salt tolerant anaerobic bacteria called Halanaerobium lacusrosei was investigated in this study. An upflow anaerobic packed bed reactor was operated continuously with synthetic saline wastewater at different hydraulic retention times, initial COD and salt concentrations. Under the different operating conditions the organic loading rates were determined. The maximum COD removal efficiency was obtained at low initial COD concentrations. No substrate inhibition effect was observed at high feed CODs. Increasing hydraulic retention time resulted in an improvement in the COD removal. Increasing salt concentration resulted in decreasing in COD removal performance on the system. This result was evaluated as salt inhibition effect on COD removal. 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 calculated. The results of this study indicated that it is possible to treat high saline wastewater by using anaerobic treatment methods. Inclusion of halophilic anaerobic bacteria into the reactor resulted in high COD removal efficiencies especially at high salt concentration.