High salinity in molasses wastewaters shifts anaerobic digestion to carboxylate production

WATER RESEARCH

卷:98

Article

De Vrieze, Jo¹  Coma, Marta^1,4  Debeuckelaere, Matthias¹  Van der Meeren, Paul²  Rabaey, Korneel^1,3 

[1] Univ Ghent, CMET, Coupure Links 653, B-9000 Ghent, Belgium

[2] Dept Appl Analyt & Phys Chem, Coupure Links 653, B-9000 Ghent, Belgium

[3] Univ Queensland, Adv Water Management Ctr, Brisbane, Qld 4072, Australia

[4] Univ Bath, CSCT, Bath BA2 7AY, Avon, England

关键词: Carboxylate production;    Fermentation;    Methane;    Microbial community;    Salinity;   

DOI  :  10.1016/j.watres.2016.04.035

来源: Elsevier

【 摘 要 】

Biorefinery wastewaters are often treated by means of anaerobic digestion to produce biogas. Alternatively, these wastewaters can be fermented, leading to the formation of carboxylates. Here, we investigated how lab-scale upflow anaerobic sludge blanket reactors could be shifted to fermentation by changing organic loading rate, hydraulic retention time, pH, and salinity. A strong increase in volatile fatty acid concentration up to 40 g COD L-1 was achieved through increasing salinity above 30 mS cm(-1), as well as a decrease in methane production by more than 90%, which could not be obtained by adjusting the other parameters, thus, indicating a clear shift from methane to carboxylate production. Microbial community analysis revealed a shift in bacterial community to lower evenness and richness values, following the increased salinity and VFA concentration during the fermentation process. A selective enrichment of the hydrogenotrophic Methanomicrobiales took place upon the shift to fermentation, despite a severe decrease in methane production. Particle size distribution revealed a strong degranulation of the sludge in the reactor, related to the high salinity, which resulted in a wash-out of the biomass. This research shows that salinity is a key parameter enabling a shift from methane to carboxylate production in a stable fermentation process. (C) 2016 Elsevier Ltd. All rights reserved.

【 授权许可】

Free