Enhanced biomethane production from organic matter recovered from municipal wastewater by a pilot-scale plant continuous high-rate contact stabilization process

High-rate contact stabilization (HiCS) processes for efficiently recovering organic matter from municipal wastewater are gaining attention as a means of producing renewable energy. In this study, a pilot-scale continuous HiCS process was applied to the effluent from a primary clarifier at a municipal wastewater treatment plant-a setting rarely reported in the literature, despite its importance for future full-scale implementation. The results confirmed that the continuous HiCS process recovers more organic matter than the conventional activated sludge (CAS) process while reducing organic matter oxidation. Biomethane potential testing further demonstrated that sludge recovered from the HiCS process generated methane at higher yields and faster rates compared to sludge from the CAS process. Moreover, the energy recovered per unit of removed organic matter in the HiCS process under practical operating conditions was higher than that achieved with the CAS process.