Abstract
This research proposes and demonstrates, for the first time, the utilization of swine manure as a complex feedstock to produce high-value medium chain fatty acids (MCFA). The two-stage anaerobic digestion (AD) carboxylates platform was adopted for the conversion of swine manure to short chain fatty acids (SCFAs) and then SCFAs to MCFA (n-caproate, n-heptanoate, and n-caprylate) with ethanol supplementation. We defined the appropriate initial pH of 10.0 for SCFAs production with a carbon conversion rate of 71.2%, and acetate, propionate were the main products, which accounted for around 72.9% of the total SCFAs in the primary stage (I). Through the addition of ethanol, 61.3% of the converted carbon in the complex SCFAs solution was converted into MCFA (C6-C8) in the chain elongation stage (II), while only 6.7% was attributed to methane formation. The concentrations of n-caproate, n-heptanoate, and n-caprylate reached 8.6 g COD/L (3.9 g/L), 6.4 g COD/L (2.7 g/L), and 2.6 g COD/L (1.07 g/L), respectively. This study achieved a relatively higher concentration of n-heptanoate compared with past studies of MCFA from other feedstock. These findings demonstrated a new route for resource recovery and the operating parameters for producing MCFA from swine manure.
Original language | English (US) |
---|---|
Pages (from-to) | 478-487 |
Number of pages | 10 |
Journal | Waste management (New York, N.Y.) |
Volume | 113 |
DOIs | |
State | Published - Jul 3 2020 |
Bibliographical note
KAUST Repository Item: Exported on 2020-10-01Acknowledgements: We thank all our colleagues for their recommendations and support during this study. Funding for the study was provided by the Agriculture Research System of China (CARS-35-10B), and the Central Public-Interest Scientific Institution Basal Research Fund (NO. BSRF201912) of China.