Granular activated carbon supplementation enhances anaerobic digestion of lipid-rich wastewaters. (June 2021)

• Record Type: Journal Article
• Authors: Tan, Lea Chua; Lin, Richen; Murphy, Jerry D.; Lens, Piet N.L.
• Is Part Of: Renewable energy. Volume 171(2021)
• Page Start: 958
• Page End: 970
• Publication Date: 2021-06
• Subjects: Activated carbon -- Long-chain fatty acid -- Lipid wastewater -- Direct interspecies electron transfer -- Methane potential assay; Renewable energy sources -- Periodicals; Power resources -- Periodicals; Énergies renouvelables -- Périodiques; Ressources énergétiques -- Périodiques; 333.794
• DOI: 10.1016/j.renene.2021.02.087
• Languages: English
• ISSNs: 0960-1481

Abstract

Abstract: This study investigated the application of a conductive material, granular activated carbon (GAC), as an approach to improve anaerobic lipid degradation and methane production. Anaerobic biomethane potential (BMP) assays were performed in 120 ml batch anaerobic digestion (AD) vials using 5 gVS/L anaerobic sludge as inoculum. Different BMP assays were carried out testing the impact of increasing GAC concentrations (0–33 g/L), use of different sludge types (granular vs. crushed), different substrates (oleate C18:1, butter and dairy wastewaters) and different temperatures (15, 37 and 55 °C). Experimental results and model fitting showed that addition of GAC supports faster methane production, i.e. the lag-phase decreased by 2–1000% depending on the GAC concentration and AD temperature. GAC addition also showed faster consumption of both volatile fatty acid and long-chain fatty acid, particularly palmitate (C16:0). Thermodynamic modelling suggested that GAC-induced direct interspecies electron transfer is kinetically superior to conventional indirect hydrogen transfer during AD of oleate. However, when the GAC concentration exceeded 8.0 g/L, there was a 20–50% decrease in the maximum methane production compared to the control. Overall, GAC supplementation has a significant potential to improve the digestion of lipid-rich wastewater which benefits design of modern bioenergy systems. Graphical abstract: Image 1 Highlights: Granular activated carbon (GAC) addition improved AD of lipid-rich wastewaters. Addition at 33.0 g/L GAC decreased the lag-phase time by 1000%. Adding more than 8.0 g/L GAC lowered the maximum methane production by 20–50%. Consumption of volatile fatty acids increased 2–5 fold with GAC addition. Degradation rates of long-chain fatty acids increased by 50% with GAC addition.