Characterisation and perspectives of energetic use of dissolved gas recovered from anaerobic effluent with membrane contactor

Biogas is a source of renewable energy, and its production and use has been validated in anaerobic-based sewage treatment plants (STPs). However, in these systems, a large amount of methane is lost as dissolved methane (D-CH4) in the liquid effluent. In this study, the characteristics and potential energetic uses of the gas recovered during the desorption of D-CH4 from anaerobic effluents with hollow fibre membrane contactors were investigated. A pilot-scale experiment was performed using sewage and two types of membrane contactors. The recovered gas contained considerable amounts of CH4, CO2, H2S, N-2, and O-2; therefore, a gas upgrade is required prior to its use as a biofuel. The recovery process should be energetically self-sustainable, and induce a considerable decrease in the STP carbon footprint. Recovering D-CH4 with membrane contactors could increase the energetic potential of anaerobic-based STPs up to 50 % and allow for more sustainable systems.

Automated summary

This study investigated the characteristics and potential energetic uses of gas recovered from the desorption of dissolved methane (D-CH4) in anaerobic effluents using hollow fibre membrane contactors. The recovered gas contained significant amounts of methane, carbon dioxide, hydrogen sulfide, nitrogen, and oxygen, requiring gas upgrading prior to use as a biofuel. The recovery process should be energetically self-sustainable and reduce the carbon footprint of sewage treatment plants considerably. Recovering D-CH4 with membrane contactors could increase the energetic potential of anaerobic-based sewage treatment plants by up to 50% and allow for more sustainable systems.