Potential of Biogas Production in Anaerobic Co-digestion of Opuntia ficus-indica and Slaughterhouse Wastes

Purpose This study assessed the co-digestion of slaughterhouse wastewater (SWW) with Opuntia ficus-indica (OFI) under semi-continuous conditions. Methods Four different mixing ratios were studied at mesophilic temperature (38 +/- 1 degrees C): 100% SWW, 75% SWW/25% OFI, 25% SWW/75% OFI and 100% OFI. Process parameters such as biogas production, methane content, redox potential, pH, alkalinity, NH4-N, and VFA were used to infer differences in the bioreactors. Results Biodigester 2 (75% SWW and 25% OFI) presented the best cumulative biogas yield and methane content with 86 L and 57% (v/v), respectively. Inhibition of the biogas production process was observed in the remaining reactors. Conclusion The results showed that the co-digestion of SWW with OFI residues improved process performance in terms of biogas production. This improvement demonstrated that OFI could be applied as a novel co-substrate in systems digesting wastewaters that contain high levels of nitrogen compounds. [GRAPHICS] .