Reflux of acidizing fluid for enhancing biomethane production from cattle manure in plug flow reactor.

Highlights • A quick start-up strategy was developed for biogas production in plug flow reactor. • Reflux of acidizing fluid (RAF) could effectively enhance the AD performance. • RAF could improve the microbial community structure and accelerate hydrolysis process. • This study provides a practical way for enhanced biogas production from cattle manure. Abstract The performance and microbial community succession of a 36 L working volume plug flow reactor was evaluated for treated cattle manure at an organic loading rate of 2.67 g-TS/L/day, a temperature of 38 °C ± 1 °C, and a hydraulic retention time of 18 days. A reflux of acidizing fluid effectively enhanced anaerobic digestion performance and promoted optimization of microbial community structure. The average biogas volume production rate was 1.08 L biogas/L reactor, which was 116.5% higher than the control without reflux of acidizing fluid. The specific qmethane production yield and methane content reached 0.204 L/g VS and 70%. Moreover, methane yield achieved 0.34 m3/kg removal COD with a COD removal of about 70.56%. The bacteria genera Christensenellaceae , Bacteroidales , vadinBC27 , Ruminococcaceae and Treponema_2 were further enriched. Methanosarcina became the dominant methanogen in the whole PFR operation process. This study offers new opportunities for producing renewable energy from enhanced cattle manure biodegradability. [ABSTRACT FROM AUTHOR]