Optimization of Hydrogen and Methane Co-production from Co-digestion of Canned Seafood Wastewater with Glycerol Waste in a Two-stage Continuous System: Comparing CSTR-PFR and CSTR-CSTR Reactors

Abstract

The challenge posed by canned seafood wastewater (CSW) involves a low COD of 6.80 g/L and a high protein concentration of 3.56 g/L, making it unsuitable for hydrogen and methane production. Consequently, the potential return on investment for establishing a commercial system remains inadequate. To address this issue, a two-stage anaerobic digestion system incorporating co-digestion with glycerol waste (GW) was implemented. The two-stage co-digestion of CSW with GW, at various mixing ratios of 99:1, 98:2, 97:3, 96:4, and 95:5% (v/v), resulted in hydrogen yields of 15.6, 33.6, 38.7, 65.0, and 6.3 ml H<inf>2</inf>/g COD, respectively, while methane yields were measured at 311, 320, 326, 345, and 99 ml CH<inf>4</inf>/g COD, correspondingly. The ideal conditions for achieving the highest yields of hydrogen and methane from the anaerobic co-digestion of CSW with GW were found to be at a mixing ratio of 96:4% (v/v). The ongoing production of hydrogen and methane in a two-stage process utilizing CSTR-PFR and CSTR-CSTR reactors can yield hydrogen and methane at rates of 27.44 and 163.61 L/L of wastewater, and 20.41 and 145.35 L/L of wastewater, respectively. Anaerobic co-digestion of CSW with GW could enhance the production of hydrogen and methane from a two-stage anaerobic digestion system.