Sustainable carbon management in aerobic granular sludge for municipal wastewater treatment
Year: 2025
Type: article
Abstract: • A pilot-scale AGS reactor was operated with and without primary sedimentation. • Primary sedimentation resulted in 30% higher overall biogas production. • No primary sedimentation enabled efficient denitrification without external carbon. • Price of biogas and biomethane potential of sludge affect sustainability assessment. Aerobic granular sludge (AGS) operated with pre-settled wastewater enables separation of organics with high biomethane potential. However, organic compounds are also needed to support denitrification, and external carbon may be needed to achieve low effluent nitrogen concentrations. This study evaluated the impact of primary sedimentation on carbon management in AGS processes. A pilot-scale reactor reached effluent nitrate concentrations of 2–3 mg NO 3 -N/L when fed with pre-settled wastewater with the addition of 0.8 ± 0.2 g COD/g N as methanol in the post-denitrification phase, or when fed with raw wastewater without an external carbon source. The biogas potential of the whole process was 25 % higher with primary sedimentation. A sustainability assessment showed that the benefits of increased biogas production with primary sedimentation could outweigh the drawbacks associated with the use of methanol as external carbon source both in terms of economy and CO 2 emissions, but methane price and biogas yield affect the assessment.
Source: Bioresource Technology
Authors: Therese Areskoug, Johanna Arita Mendoza, Oskar Modin, Dag Lorick, Susanne Tumlin, Britt-Marie Wilén
Institutions: Gryaab (Sweden), Chalmers University of Technology
Language: English
Subfield: Pollution
Field: Environmental Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,880
Funder: Swedish Institute
OpenAlex ID: W4410022731