Comparison of biochemical methane potential and methanogen morphology of different organic solid wastes co-digested anaerobically with treatment plant sludge

This paper describes biomethanation of tannery limed fleshing (TLF), fruits and vegetables (FVW), and sugarcane juice residue (SJR) with pre-fermented tannery-based common effluent treatment plant sludge (CETP), as an inoculum. The BMP, microbial morphology and other bioprocess efficiency parameters were evaluated using a laboratory scale batch reactor, with a substrate/inoculum ratio of 3:1 under a mesophilic anaerobic (35 ± 2 °C) condition and mixed at 100 rpm in orbit shaker. Maximum cumulative biogas yield was observed in FVW (2468.50 ± 0.44 Nm mL/d) followed by TLF and SJR comparatively to the inoculum. The specific methane yield observed ranged from 0.169 ± 0.05 to 0.478 ± 0.00 Nm L/g VSr for the wastes, against 0.204 ± 0.01 Nm L/g VSr for control treatment. The mixture of all the three wastes (CLFS) benefitted to yield more biogas compared to the mono-digestion. The highest VSr and sCODr efficiency of 62.44 ± 0.32 and 93.46 ± 1.04% obtained in FVW compared to other wastes, coincides with the methanogenic microbial count and densities. A good correlation (R2 = 0.82) was also observed between the experimental BMP and stoichiometric methane potential of the various organic solid wastes.