Comparison of pre- and inter-stage aerobic treatment of wastewater sludge: Effects on biogas production and COD removal

• Published in: Bioresource technology Vol. 247; pp. 332 - 339
• Main Authors: Rennuit, Charlotte, Triolo, Jin Mi, Eriksen, Søren, Jimenez, Julie, Carrère, Hélène, Hafner, Sasha D.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.01.2018; Elsevier
• Subjects: Accessibility; Anaerobiosis; Biofuels; Bioreactors; Complexity; Environmental Sciences; Life Sciences; Methane; Organic matter loss; Recalcitrance; Sewage; Waste Disposal, Fluid; Waste Water; Methane; Accessibility; Organic matter loss; Recalcitrance; Complexity; methane; complexity; organic matter loss; recalcitrance; accessibility
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2017.08.128

[Display omitted] •Inter-stage TAD had less oxidation loss than pre-treatment.•TAD pre-treatment reduced CH4 yield while inter-stage increased it slightly (1.8–2.6%).•Combined anaerobic/aerobic treatment can substantially increase COD removal.•TAD increased methane yield from previously digested sludge >40%.•TAD treatment is best for recalcitrant substrates or in an inter-stage configuration. The aim of this study was to investigate thermophilic (55°C) aerobic digestion (TAD) as pre- and inter-stage treatment of sludge anaerobic digestion and to analyse the change in organic matter accessibility and complexity. Pre-treatment decreased methane yield (up to −70%), due to oxidation losses whereas inter-stage treatment slightly improved overall methane yield (+2.6%) and total COD removal (+5%) compared to control. Anaerobic degradability and COD removal in the second anaerobic stage significantly increased, by 13–40%. Organic matter fractionation showed that TAD led to an increase in sludge organic matter accessibility in all cases. Organic matter complexity, measured by fluorimetry, increased after TAD pre-treatment whereas it remained constant after inter-stage treatment. TAD was shown to be more efficient if applied to a more recalcitrant substrate and should thus be used as inter-stage treatment to avoid decreasing methane production.