The objective of this study was to assess the feasibility of co-digesting food waste (FW) and de-oiled grease trap waste (GTW) to improve the biogas production. A lab-scale mesophilic digester (MD), a temperature-phased anaerobic digester (TPAD) and a TPAD with recycling (TPAD-R) were synchronously operated under mono-digestion (FW) and co-digestion (FW. +. de-oiled GTW). Co-digestion increased the biogas yield by 19% in the MD and TPAD-R, with a biogas yield of 0.60. L/g VS added. Specific methanogenic activity in the TPAD-R was much higher than that in the MD. In addition to methane, hydrogen at a yield of approximately 1. mol/mol hexose was produced in the TPAD-R. Alkalinity was consumed more in the co-digestion than in mono-digestion. Co-digestion resulted in more lipid accumulation in each digester. The MD favored the degradation of lipid and conversion of long-chain fatty acids more than the TPAD and TPAD-R.
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