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Description
Composting provides a sustainable pathway for organic waste management, converting biodegradable residues into nutrient-rich soil amendments that enhance soil fertility and support climate-smart agriculture. This study applied a chemometric and model-driven framework to evaluate compost quality across 20 randomly selected facilities in Ghana, integrating physicochemical, microbial, and energetic parameters. Compost pH ranged from 8.65–9.30, bulk density from 710.10–792.00 kg/m³, and organic matter content averaged 24.94%. Electrical conductivity (1.10–1.96 dS/m) remained within acceptable agronomic limits. Nutrient composition was favourable, with nitrogen (0.78–1.98%), phosphorus (0.47–0.99%), and potassium (0.65–0.93%) supporting its role as a fertilizer substitute. Carbon-to-nitrogen ratios (mean: 10.32) were inversely related to nitrogen availability, which reached up to 2.48% in more stabilized composts. Microbial analysis confirmed significant pathogen inactivation: faecal coliforms declined by 94.5% (117 to 6.5 cfu/g), while Escherichia coli and Salmonella spp. were completely eliminated, reducing the pathogenic index from 0.427 to 0.013 (p < 0.0001). Heavy metals, including arsenic (0.01–0.21 mg/kg) and cadmium (0.04–0.18 mg/kg), remained within permissible thresholds, although sporadic variations highlight the need for stricter quality monitoring. Advanced statistical analysis revealed significant effects of composting methods (F = 5373.30, p < 0.0001) and facility conditions (F = 10746.51, p < 0.0001) on compost quality, with strong interaction effects (F = 10190.31, p < 0.0001). Principal Component Regression extracted five components explaining 81.97% of total variance, with predictive strength (R² = 0.82; CV R² = 0.75 ± 0.08), demonstrating the robustness of chemometric models. The findings highlight the potential of standardized, model-based assessments to ensure compost safety, optimize agronomic use, and strengthen Ghana’s composting industry and general environmental sustainability.