Biocells for Waste Valorization: Enhancing Methane Production and Leachate Management in the Anaerobic Degradation of Green Waste and WWTP Biosolids from Ambato, Ecuador

Abstract

The disposal of solid waste in conventional landfills poses critical environmental challenges, including uncontrolled greenhouse gas emissions and highly contaminated leachate. Bioreactor landfills with leachate recirculation offer an effective alternative, accelerating organic matter degradation and enhancing methane production for energy recovery. This study evaluates methane production, leachate quality, and organic matter stabilization in laboratory-scale biocells integrating biosolids from the Ambato wastewater treatment plant (WWTP), compost, and green waste. Three replicate biocells were operated over 12 weeks with leachate recirculation to optimize nutrient removal and biogas production. Methane generation stabilized after 21 days, while phosphorus and ammonium concentrations in the leachate ranged from 10–15 mg/L and 50–80 mg/L, respectively. Heavy metal concentrations significantly decreased, with final cadmium and chromium levels falling below regulatory discharge limits, reaching 0.02 mg/L and 0.05 mg/L, respectively. Chemical Oxygen Demand (COD) was reduced by 85%, reaching a final concentration of approximately 300 mg/L. These findings highlight the feasibility of incorporating WWTP biosolids in biocells to enhance organic solid waste degradation, sustainable landfill leachate management, and renewable energy generation in Ambato, Ecuador.