Effect and behaviour of different substrates in relation to the formation of aerobic granular sludge

Abstract

When aerobic granular sludge is applied for industrial wastewater treatment, different soluble substrates can be present. For stable granular sludge formation on volatile fatty acids (e.g. acetate), production of storage polymers under anaerobic feeding conditions has been shown to be important. This prevents direct aerobic growth on readily available chemical oxygen demand (COD), which is thought to result in unstable granule formation. Here, we investigate the impact of acetate, methanol, butanol, propanol, propionaldehyde, and valeraldehyde on granular sludge formation at 35 °C. Methanogenic archaea, growing on methanol, were present in the aerobic granular sludge system. Methanol was completely converted to methane and carbon dioxide by the methanogenic archaeum Methanomethylovorans uponensis during the 1-h anaerobic feeding period, despite the relative high dissolved oxygen concentration (3.5 mg O2 L−1) during the subsequent 2-h aeration period. Propionaldehyde and valeraldehyde were fully disproportionated anaerobically into their corresponding carboxylic acids and alcohols. The organic acids produced were converted to storage polymers, while the alcohols (produced and from influent) were absorbed onto the granular sludge matrix and converted aerobically. Our observations show that easy biodegradable substrates not converted anaerobically into storage polymers could lead to unstable granular sludge formation. However, when the easy biodegradable COD is absorbed in the granules and/or when the substrate is converted by relatively slow growing bacteria in the aerobic period, stable granulation can occur.Electronic supplementary materialThe online version of this article (doi:10.1007/s00253-014-6358-3) contains supplementary material, which is available to authorized users.

Full scale performance of the aerobic granular sludge process for sewage treatment

“…Aerobic granules are also characterised by their layered structure. The 49 presence of an aerobic outer layer and an anaerobic or anoxic core, facilitates co-existence of 50 nitrifying organisms in the outer layers of the granules and denitrifying phosphate 51 accumulating organisms (dPAO), as well as (facultative) anaerobic organisms towards the 52 centre of the granules (Gieseke et al 2001, Winkler et al 2012, Pronk et al 2015. Due to 53 this structure, aerobic granular sludge can simultaneously remove phosphorus, nitrogen and 54 COD (chemical oxygen demand) from the liquid (de Kreuk et al 2005, Gonzalez-Gil and 55 Holliger 2011).…”

Treatment of high strength industrial wastewater with membrane bioreactors for water reuse: Effect of pre-treatment with aerobic granular sludge on system performance and fouling tendency

“…AGS have been successfully implemented for the treatment of both municipal and industrial wastewater. The literature studies demonstrated that aerobic granules feature a compact and thick structure, thus ensuring a great ability to withstand adverse environmental conditions, such as loading variation, obtaining very high effluent quality at the same time [17][18][19][20]. Indeed, the granular sludge features very high settling ability and allows to maintain higher biomass concentrations, thus reducing the plant footprint [21].…”

Modeling hydraulic transport and anaerobic uptake by PAOs and GAOs during wastewater feeding in EBPR granular sludge reactors

“…Among those, the impacts of the VFA composition on PAO and GAO metabolisms and selection (Gonzalez-Gil and Holliger, 2011;Lopez-Vazquez et al, 2009;Weissbrodt et al, 2013b), and of different ranges of substrates and salinities on additional microbial processes can be studied (Pronk et al, 2014(Pronk et al, , 2015aWelles et al, 2014). Among those, the impacts of the VFA composition on PAO and GAO metabolisms and selection (Gonzalez-Gil and Holliger, 2011;Lopez-Vazquez et al, 2009;Weissbrodt et al, 2013b), and of different ranges of substrates and salinities on additional microbial processes can be studied (Pronk et al, 2014(Pronk et al, , 2015aWelles et al, 2014).…”

“…Model extensions can provide opportunities for solving multiple research questions. Among those, the impacts of the VFA composition on PAO and GAO metabolisms and selection (Gonzalez-Gil and Holliger, 2011;Lopez-Vazquez et al, 2009;Weissbrodt et al, 2013b), and of different ranges of substrates and salinities on additional microbial processes can be studied (Pronk et al, 2014(Pronk et al, , 2015aWelles et al, 2014). Latest molecular and ecophysiology investigations further highlighted that engineered EBPR microbial ecosystems consist of a diversity of populations within the PAO and GAO guilds, which could be considered in model extensions as well (Albertsen et al, 2016;Forbes et al, 2009;Lanham et al, 2013;Nielsen et al, 2012;Weissbrodt et al, 2014c;Welles et al, 2015).…”