Abstract
BACKGROUND: This study considers batch treatment of saline wastewater in an upflow anaerobic packed bed reactor by salt tolerant anaerobic organisms Halanaerobium lacusrosei.
RESULTS: The effects of initial chemical oxygen demand (COD) concentration (COD~0~ = 1880–9570 mg L^−1^), salt concentration ([NaCl] = 30–100 g L^−1^) and liquid upflow velocity (V~up~ = 1.0–8.5 m h^−1^) on COD removal from salt (NaCl)‐containing synthetic wastewater were investigated. The results indicated that initial COD concentration significantly affects the effluent COD concentration and removal efficiency. COD removal was around 87% at about COD~0~ = 1880 mg L^−1^, and efficiency decreased to 43% on increasing COD~0~ to 9570 mg L^−1^ at 20 g L^−1^ salt concentration. COD removal was in the range 50–60% for [NaCl] = 30–60 g L^−1^ at COD~0~ = 5200 ± .100 mg L^−1^. However, removal efficiency dropped to 10% when salt concentration was increased to 100 g L^−1^. Increasing liquid upflow velocity from V~up~ = 1.0 m h^−1^ to 8.5 m h^−1^ provided a substantial improvement in COD removal. COD concentration decreased from 4343 mg L^−1^ to 321 mg L^−1^ at V~up~ = 8.5 m h^−1^, resulting in over 92% COD removal at 30 g L^−1^ salt‐containing synthetic wastewater.
CONCLUSION: The experimental results showed that anaerobic treatment of saline wastewater is possible and could result in efficient COD removal by the utilization of halophilic anaerobic bacteria. Copyright © 2008 Society of Chemical Industry