Effects of the reduction of the hydraulic retention time to 1.5 days at constant organic loading in CSTR, ASBR, and fixed-bed reactors – performance and methanogenic community composition

Schmidt, Thomas and Ziganshin, Ayrat M. and Nikolausz, Marcell and Scholwin, Frank and Nelles, Michael and Kleinsteuber, Sabine and Proter, Jurgen (2014) Effects of the reduction of the hydraulic retention time to 1.5 days at constant organic loading in CSTR, ASBR, and fixed-bed reactors – performance and methanogenic community composition. Biomass and Bioenergy, 69. pp. 241-248. ISSN 0961-9534

Abstract

The hydraulic retention time (HRT) is one of the key parameters in biogas processes and often it is postulated that a minimum HRT of 10e25 days is obligatory in continuous stirred tank reactors (CSTR) to prevent a washout of slow growing methanogens. In this study the
effects of the reduction of the HRT from 6 to 1.5 days on performance and methanogenic community composition in different systems with and without immobilization operated with simulated thin stillage (STS) at mesophilic conditions and constant organic loading rates (OLR) of 10 g L�1d�1 of volatile solids were investigated. With the reduction of the HRT process instability was first observed in the anaerobic sequencing batch reactor (ASBR) (at HRT of 3 days) followed by the CSTR (at HRT of 2 days). The fixed bed reactor (FBR) was stable until the end of the experiment, but the reduction of the HRT to 1.5 days caused a decrease of the specific biogas production to about 450 L kg�1 of VS compared to about 600 L kg�1 of VS at HRTs of 4e5 days. Methanoculleus and Methanosarcina were the dominant genera under stable process conditions in the CSTR and the ASBR and members of Methanosaeta and Methanospirillum were only present at HRT of 4 days and lower. In the effluent
of the FBR Methanosarcina spp. were not detected and Methanosaeta spp. were more abundant then in the other reactors.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Files associated with this item cannot be displayed due to copyright restrictions.
Faculty / Department / School: No Faculty
Date Deposited: 24 May 2017 05:08
Last Modified: 30 May 2017 05:20
Uncontrolled Keywords: biogas; methanogenic community; reactors; retention time; washout
Fields of Research : 09 Engineering > 0907 Environmental Engineering > 090703 Environmental Technologies
Identification Number or DOI: 10.1016/j.biombioe.2014.07.021
URI: http://eprints.usq.edu.au/id/eprint/32443

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