Biochemical methane potential of water hyacinth and the organic fraction of municipal solid waste using leachate from Mexico City's Bordo Poniente composting plant as inoculum

In Mexico City, both the organic fraction of municipal solid waste (OFMSW) and the spread of water hyacinth among water bodies have been reported to increase greatly each year. These wastes have been associated with health problems and with the contamination of water bodies, soil, and air. Previous studies have demonstrated that water hyacinth and OFMSW can be sustainably managed using anaerobic digestion (AD) and anaerobic co-digestion (ACD) processes. In the present study, the biochemical methane potential of water hyacinth and OFMSW was determined. Leachate from Mexico City's Bordo Poniente composting plant was used as inoculum, and the effects of two substrate-to-inoculum (S:I) ratios on volatile solids (VS) were investigated at lab-scale and under thermophilic conditions with a hydraulic retention time of 50 d. Based on S:I ratio, the AD of OFMSW with an S:I of 1:1 yielded more methane (387 ± 25 NL_CH4/kgVS_added) than the ACD process (337 ± 15 NL_CH4/kgVS_added), but not significantly (p > 0.05). Inoculum showed great potential to digest wastes used in this research. The ACD S:I ratio of 1:1 demonstrated that the AD process is both to produce renewable energy and to resolve problems associated with water hyacinth, OFMSW, and leachate.