Strategies to Suppress Hydrogen-Consuming Microorganisms Affect Macro and Micro...

• Autor(es): Abreu, A. A. ; Alves, J. I. ; Pereira, M. A. ; Sousa, D. Z. ; Alves, M. M.
• Data: 2011
• Identificador Persistente: http://hdl.handle.net/1822/17604
• Origem: RepositóriUM - Universidade do Minho
• Assunto(s): biohydrogen; dark fermentation; image analysis; bacterial communities; EGSB reactors
• Tipo de Documento: Artigo
• Idioma: Inglês

Descrição

Treatment of anaerobic granules with heat and two chemical treatments, contacting with 2-bromoethanesulfonate (BES) and with BESþChloroform, were applied to suppress hydrogen-consuming microorganisms. Three mesophilic expanded granular sludge bed (EGSB) reactors— RHeat, RBES, and RBESþChlo—were inoculated with the treated sludges and fed with synthetic sugar-based wastewater (5 gCOD L 1, HRT 20–12 h). Morphological integrity of granules and bacterial communities were assessed by quantitative image analysis and 16S rRNA gene based techniques, respectively. Hydrogen production in RHeat was under 300mLH2 L 1 day 1, with a transient peak of 1,000 mLH2 L 1 day 1 after decreasing HRT. In RBESþChlo hydrogen production rate did not exceed 300mLH2 L 1 day 1 and there was granule fragmentation, release of free filaments from aggregates, and decrease of granule density. In RBES, there was an initial period with unstable hydrogen production, but a pulse of BES triggered its production rate to 700 200mLH2 L 1 day 1. This strategy did not affect granules structure significantly. Bacteria branching within Clostridiaceae and Ruminococcaceae were present in this sludge. This work demonstrates that, methods applied to suppress H2-consuming microorganisms can cause changes in the macro- and microstructure of granular sludge, which can be incompatible with the operation of high-rate reactors.