Methane recovery efficiency in a submerged anaerobic membrane bioreactor (SAnMBR) treating sulphate-rich urban wastewater: Evaluation of methane losses with the effluent

• Published in: Bioresource technology 2012-08, Vol.118, p.67-72
• Main Authors: Giménez, J.B., Martí, N., Ferrer, J., Seco, A.
• Format: Article
• Language: English
• Subjects: Anaerobic treatment; Anaerobiosis; Biofuels - analysis; Biological Oxygen Demand Analysis; Bioreactors; Cities; Dissolved methane; effluents; energy recovery; greenhouse gas emissions; Membranes; Membranes, Artificial; Methane; Methane - analysis; methane production; Methane saturation index; Pilot Projects; Recovery; sludge; Submerged; Submerged anaerobic membrane bioreactor (SAnMBR); sulfates; Sulfates - isolation & purification; Sulphate-rich wastewater; Temperature; upflow anaerobic sludge blanket reactor; Urban wastewater; Waste Disposal, Fluid; Waste water; wastewater; Wastewater treatment; Water Purification - instrumentation; Water Purification - methods
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2012.05.019

► SAnMBR represents a sustainable approach for urban wastewater treatment. ► The biogas-assisted mixing avoids super-saturation of methane at the effluent. ► The methane recovery efficiency obtained at 20°C was slightly lower than at 33°C. ► A temperature drop reduced the treatments efficiency and increased gases solubility. ► The methane recovery efficiency was mainly affected by the influent COD/S-SO4 ratio. The present paper presents a submerged anaerobic membrane bioreactor (SAnMBR) as a sustainable approach for urban wastewater treatment at 33 and 20°C, since greenhouse gas emissions are reduced and energy recovery is enhanced. Compared to other anaerobic systems, such as UASB reactors, the membrane technology allows the use of biogas-assisted mixing which enhances the methane stripping from the liquid phase bulk. The methane saturation index obtained for the whole period (1.00±0.04) evidenced that the equilibrium condition was reached and the methane loss with the effluent was reduced. The methane recovery efficiency obtained at 20°C (53.6%) was slightly lower than at 33°C (57.4%) due to a reduction of the treatment efficiency, as evidenced by the lower methane production and the higher waste sludge per litre of treated wastewater. For both operational temperatures, the methane recovery efficiency was strongly affected by the high sulphate concentration in the influent wastewater.