title: Digester performance and microbial community changes in thermophilic and mesophilic sequencing batch reactors fed with the fine sieved fraction of municipal sewage.
abstract: This study investigates the start-up and operation of bench-scale mesophilic (35 °C) and thermophilic (55 °C) anaerobic sequencing batch reactor (SBR) digesters treating the fine sieved fraction (FSF) from raw municipal sewage. FSF was sequestered from raw municipal wastewater, in the Netherlands, using a rotating belt filter equipped with a 350 micron mesh. For the given wastewater, the major component of FSF was toilet paper, which is estimated to be 10-14 kg per year per average person in the western European countries. A seven months adaptation time was allowed for the thermophilic and mesophilic digesters in order to adapt to FSF as the sole substrate with varying dry solids content of 10-25%. Different SBR cycle durations (14, 9 and 2 days) were applied for both temperature conditions to study methane production rates, volatile fatty acids (VFAs) dynamics, lag phases, as well as changes in microbial communities. The prevailing sludge in the two digesters consisted of very different bacterial and archaeal communities, with OP9 lineage and Methanothermobacter being pre-dominant in the thermophilic digester and Bacteroides and Methanosaeta dominating the mesophilic one. Eventually, decreasing the SBR cycle period, thus increasing the FSF load, resulted in improved digester performances, particularly with regard to the thermophilic digester, i.e. shortened lag phases following the batch feedings, and reduced VFA peaks. Over time, the thermophilic digester outperformed the mesophilic one with 15% increased volatile solids (VS) destruction, irrespective to lower species diversity found at high temperature.
authors.affiliation: Sanitary Engineering Section, Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, Stevinweg 1, 2628 CN, Delft, The Netherlands. Electronic address: S.M.D.Ghasimi@tudelft.nl.
authors.forename: Dara S M
authors.initials: DS
authors.lastname: Ghasimi
authors.affiliation: Sanitary Engineering Section, Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, Stevinweg 1, 2628 CN, Delft, The Netherlands; State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, No. 73 Huanghe Road, Harbin, 150090, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Tao
authors.affiliation: Sanitary Engineering Section, Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, Stevinweg 1, 2628 CN, Delft, The Netherlands.
authors.forename: Merle
authors.initials: M
authors.lastname: de Kreuk
authors.affiliation: Environmental Biotechnology Section, Department of Biotechnology, Faculty of Applied Science, Delft University of Technology, Julianalaan 67, 2628 BC, Delft, The Netherlands.
authors.forename: Ben
authors.initials: B
authors.lastname: Abbas
authors.affiliation: Waternet, Korte Ouderkerkerdijk 7, P.O. Box 94370, 1090 GJ, Amsterdam, The Netherlands.
authors.forename: Marcel H
authors.initials: MH
authors.lastname: Zandvoort
authors.affiliation: Sanitary Engineering Section, Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, Stevinweg 1, 2628 CN, Delft, The Netherlands.
authors.forename: Jules B
authors.initials: JB
authors.lastname: van Lier
mesh_terms: D019149:Bioreactors; D005232:Fatty Acids, Volatile / Q000378:metabolism*; D008697:Methane / Q000378:metabolism*; D064307:Microbiota; D009426:Netherlands; D012722:Sewage / Q000032:analysis*; D013696:Temperature; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000032:analysis
chemical_list: D005232:Fatty Acids, Volatile; D008697:Methane; D012722:Sewage; D062065:Wastewater
keywords: Anaerobic digestion; Cellulose; Fine sieved fraction (FSF); Methane potential; Microbial community; Volatile fatty acids