Anaerobic digestion is an important technology for waste treatment and renewable energy production. To pursue avenues of improvement in digester technology and foster a circular bioeconomy, this study investigated the impact of activated carbon, formic acid, and sodium bicarbonate addition on the performance, parameters, and ecology of bench-scale anaerobic reactors. The study found that the addition of formate in combination with activated carbon was able to significantly increase the production of biogas from digestate collected from the South Campus Anaerobic Digester (SCAD). Reactors treated with formic acid also showed evidence of superior formic acid utilization, with formic treated reactors having similar or lesser formic acid concentration than non-formic treated reactors. Additionally, formic acid treated reactors showed lower concentrations of volatile fatty acids (VFAs), including propionic and butyric acid, indicating enhanced reactor performance. DNA analysis revealed an increase in formate-scavenging methanogens and syntrophic bacteria. Thes analyses suggests that the formate treatment led to enhanced syntrophic interactions among the microbial consortia. Following these promising results, a life-cycle analysis (LCA) and were conducted on a hypothetical two-stage treatment system utilizing electrocatalysis to convert waste CO2 into formic acid for treatment of a secondary digester. The mass balance and LCA suggest that formate-treated AD has the potential to greatly enhance energy efficiency, carbon utilization, and environmental outcomes of the AD process.
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