Assessing the variability in biomethane production from the organic fraction of municipal solid waste in batch and continuous operation

• Published in: Applied energy Vol. 128; pp. 307 - 314
• Main Authors: Browne, James D., Allen, Eoin, Murphy, Jerry D.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-09-2014; Elsevier
• Subjects: Anaerobic digestion; Applied sciences; Biogas; BMP; Carbon; CSTR; Energy; Exact sciences and technology; Food waste; Foods; Inclusions; Instability; Methane; Solid wastes; Wastes; Food waste; CSTR; BMP; Anaerobic digestion; Variability; Urban waste
• ISSN: 0306-2619; 1872-9118
• DOI: 10.1016/j.apenergy.2014.04.097

•Eight organic waste streams were examined for biochemical methane potential (BMP).•Commercial food waste produced 560mL CH4 gVS−1 in continuous trials.•Raising the loading rate to 4kg VS m−3day−1 led to a reduction in methane yield.•The low C:N ratio led to levels of 7000mgNL−1 at high loading rates.•Free ammonia levels of 1000mgNL−1 were encountered at a pH of 8.
This paper examines the variability in biomethane potential from the organic fraction of municipal solid waste depending on source of origin. Eight organic waste streams were examined for biochemical methane potential (BMP). Specific methane yields of between 274 and 368mL CH4 gVS−1 for household waste and 491–535mL CH4 gVS−1 for commercial waste were achieved. Inclusion of garden waste reduced methane yields. A continuous trial on commercial food waste produced an average of 560±29mL CH4 gVS−1 at a moderate organic loading rate (OLR) of 2kg VS m−3day−1 with a hydraulic retention time (HRT) of 30days. Raising the OLR to 4kg VS m−3day−1 led to a reduction in specific methane yield. The low carbon to nitrogen (C:N) ratio of commercial food waste (14.4) led to process instability due to total ammonia nitrogen levels in excess of 7000mgL−1 towards the end of the trial.