Comparative evaluation of composting and solarization techniques for mitigating antibiotic residues, and resistance genes in poultry manure

Abstract

The improper management of poultry waste poses a growing environmental and public health threat due to accumulation of antibiotic residues, pathogenic microorganisms, and antimicrobial resistance genes (ARGs). This study investigated the effectiveness of composting, open solarization, and closed solarization in transforming poultry manure into safer, nutrient-rich material for agricultural use. Poultry waste mixed with sawdust (2:1 w/w) was treated over 60 days, with weekly monitoring of physicochemical properties, microbial load, and concentrations of tetracycline, sulfamethoxazole, ampicillin, and neomycin sulphate. Composting achieved complete degradation (100%) of all antibiotics within 50 days. For closed solarisation, ampicillin was completely removed within 60 days, while the remaining antibiotics showed varying removal efficiencies. Antibiotic removal efficiencies for open solarization ranged from 93% to 97% within 60 days. Microbial loads declined significantly under composting and closed solarization, with composting reducing counts of Escherichia coli isolates from 1.15 × 10¹¹ CFU/mL to 9.29 × 10¹⁰ CFU/mL from untreated and early-stage compost samples. Antibiotic sensitivity tests revealed a reduction in ticarcillin-resistant E. coli from 50% to 17% post-treatment, and no new resistance was observed for amikacin, meropenem, and norfloxacin in composted samples. All treatments improved nutrient content, particularly potassium, which rose from 1.52% to 6.03% under composting. Statistical correlations show temperature and moisture significantly influenced antibiotic degradation and microbial reduction (p < 0.05). Closed solarization maintained better thermal and moisture conditions than open solarization, enhancing treatment efficacy. These results confirm composting and closed solarization as robust, climate-sensitive strategies for antibiotic residue mitigation, microbial safety, and sustainable nutrient recovery in poultry waste management.