Enhanced methane production by using phytoremediated Halogeton glomeratus as substrate via anaerobic digestion

The phytoremediated plant contains rich carbon resources, but the anaerobic digestion (AD) process can be inhibited due to high Heavy metals (HMs). In this study, the phytoremediated Halogeton glomeratus (H. glomeratus) was utilized in AD. Results showed that suitable HMs improved the AD efficiency, and the HMs were positively correlated to methane production and microbiota. Compared to CK (without HMs contaminated), H. glomeratus containing HMs (TG) enhanced methane production (increased 85.5%). Also, the highest VS removal rate of 66.5% were achieved. Furthermore, the increased of hydrolytic and acidogenic Acinetbacter and Hydrogenophaga improved substrates degradation. Besides, the methanogenic Methanosarcina increased from 6.5 to 89.5%, and the methanogenic pathway shifted from hydrogenotrophic methanogenesis to aceticlastic methanogenesis. Thus, substrates conversion to methane was improved. Finally, the HMs in digestion slurry were successfully removed and decreased its secondary pollution. This study provided a potential for the resourceful utilization of the phytoremediated plants with suitable HMs concentration. © 2022 Elsevier Ltd