Three-Stage Anaerobic Co-Digestion of Food Waste and Waste Activated Sludge: Identifying Bacterial and Methanogenic Archaeal Communities and Their Correlations with Performance Parameters
- Conference: E2S2 CREATE and AIChE Waste Management Conference
- Year: 2019
- Proceeding: 2019 E2S2-CREATE and AIChE Waste Management Conference
- Group: Abstract Submissions
- Time: Wednesday, March 13, 2019 - 11:45am-12:00pm
Food waste (FW) and waste activated sludge (WAS) are critical global issues currently. To combine the benefits of high-solids anaerobic digestion (AD) and wet AD of FW and WAS to improve digester performance and methane production, a three-stage anaerobic digester was developed in this study. Three-stage anaerobic co-digestion of FW and WAS was conducted while corresponding bacterial and methanogen communities were characterized. Results showed that the average methane yield in the three-stage digester was 13-52% higher than that of one- and two-stage digester. An increase of 12-47% in volatile solids reduction was achieved in the three-stage digester, compared to the controls. Bacterial phyla Proteobacteria, Firmicutes and Bacteroidetes dominated in one-, two- and three-stage digester while genera Pseudomonas, Tissierella, and Petrimonas were selectively enriched in the three-stage digester due to functional segregation. Taxonomic analysis identified 8 dominant methanogen genera, of which Methanosarcina, Methanosaeta, Methanobacterium and Methanolinea collectively accounted for 80%. With increasing organic loading rate and digester stage number, the dominant methanogenic pathway shifted from hydrogenotrophic pattern to acetoclastic pattern and reached a final synergy of these two. Methanosarcina was enriched by 1.5-1.7 times in the three-stage digester, contributed to the enhanced methane production. The three-stage digester is promising to be applied to the industrial biogas plants after scale-up and further optimization.