Leachates generated from the degradation of green waste and biosolids from urban wastewater treatment plants (WWTPs) pose significant environmental concerns due to high concentrations of organic pollutants and heavy metals. This study proposes a hybrid treatment strategy combining electrocoagulation (EC) and UVC-activated TiO₂ photocatalysis to remediate leachates produced in laboratory-scale biocells. Initial characterization revealed critical pollutant levels: COD (1373 mg/L), BOD₅ (378 mg/L), total phosphorus (90 mg/L), ammoniacal nitrogen (201 mg/L), and metals such as Ni, Pb, and Mn levels all exceeding those set out in the Ecuadorian discharge regulations. Optimized EC achieved removal efficiencies of 62.6% for COD, 44.4% for BOD₅, 89.8% for phosphorus, and 86.2% for color. However, residual contamination necessitated a subsequent photocatalytic step. Suspended TiO₂ under UVC irradiation removed up to 81.8% of the remaining COD, 88.7% of the ammoniacal nitrogen, and 94.4% of the phosphorus. Levels of heavy metals such as Zn, Fe, Pb, Mn, and Cu were reduced by over 80%, while Cr⁶⁺ was nearly eliminated. SEM–EDS analysis confirmed successful TiO₂ immobilization on sand substrates, revealing a rough, porous morphology conducive to catalyst adhesion; however, heterogeneous titanium distribution suggests the need for improved coating uniformity. These findings confirm the potential of the EC–TiO₂/UVC hybrid system as an effective and scalable approach for treating complex biocell leachates with reduced chemical consumption.

This study investigated Coffee arabica husk (CAH) as a reinforcing filler to create sustainable biocomposites from agro-industrial waste. The research explored the relationship between processing, structure, and properties using two matrices: polylactic acid (LA) and a bio-based epoxy resin (BER). We found that CAH incorporation increased the elastic modulus in all composites, with the stiffening effect being more significant in BER-based systems. However, filler inclusion dramatically reduced composite toughness. Our analysis showed that melt processing significantly reduced the CAH aspect ratio, with BER causing a more pronounced reduction than LA. Conversely, LA showed a greater tendency to fill the porous voids of the CAH particles. This work demonstrates the crucial interaction of filler, matrix, and processing on a composite’s final performance. These materials have shown promises for sustainable packaging and other technical applications.

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. The present study investigates methane generation, leachate characteristics, and the stabilization of organic matter in laboratory-scale biocells that incorporate biosolids from the Ambato Wastewater Treatment Plant (WWTP), along with 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-1 and 50-80 mg.L-1, respectively. Heavy metal concentrations significantly decreased, with final cadmium and chromium levels falling below regulatory discharge limits, reaching 0.02 mg.L-1 and 0.05 mg.L-1, respectively. Chemical Oxygen Demand (COD) was reduced by 85%, reaching a final concentration of approximately 300 mg.L-1. 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.