Details

Autor(en) / Beteiligte

• Wu, Shu-Lin
• Wei, Wei
• Sun, Jing
• Xu, Qiuxiang
• Dai, Xiaohu
• Ni, Bing-Jie

Titel

Medium-Chain fatty acids and long-chain alcohols production from waste activated sludge via two-stage anaerobic fermentation

Ist Teil von

• Water research (Oxford), 2020-11, Vol.186, p.116381-116381, Article 116381

Ort / Verlag

Elsevier Ltd

Erscheinungsjahr

2020

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• •Medium-chain fatty acid (MCFA) and Long-chain alcohol (LCA) co-production was gained.•MCFA and LCA co-production is positively related to ethanol content.•High level of ethanol could improve the selectivity of MCFA but reduce that of LCA.•Key functional microbes for co-production of MCFA and LCA were enriched. Traditional bioenergy recovery in the form of short chain fatty acids (SCFAs) from waste activated sludge (WAS) is generally limited by economic unattractiveness and complexity of products separation. Herein, a novel biotechnology process of two-stage anaerobic fermentation for converting the WAS into high energy density, easy-separated medium chain fatty acids (MCFAs) and long-chain alcohols (LCAs) was evaluated. In this process, the WAS was first converted to WAS alkaline fermentation liquid (WASAFL), serving as electron acceptors (EAs) and inoculum, then adding ethanol as electron donor (ED) for chain elongation (CE). The co-production of MCFAs and LCAs during CE were studied under three different ED to EA ratios, i.e., 3:1, 4:1 and 5:1. Experimental results demonstrated that when the ratio of ED to EA increased from 3:1 to 5:1, the production of MCFA and LCAs respectively increased from 5.57 ± 0.17 and 2.58 ± 0.18 to7.67 ± 0.48 and 4.21 ± 0.19 g COD/L. A similar observation was made in the total product electron efficiency, increasing from 59.9% to 72.1%. However, the highest total product selectivity (i.e., 68.0%) and highest products production yield (i.e., 59.77%) were not achieved at the ED to EA ratio of 5:1 due to toxicity caused by higher accumulation of n-caproate. The kinetic analysis further confirmed that high ratio of ED to EA induced improvement in product maximum yield, production rate for both MCFAs and LCAs. Microbial community analysis indicated that Clostridium, Caproiciproducens, Acinetobacter, Exilispira, and Oscillibacter were clearly enriched in the CE reactor and had positive correlation with MCFAs and LCAs production. [Display omitted]