Decline in extractable antibiotics in manure-based composts during composting

Area of Science:

• Environmental Science
• Agricultural Science
• Analytical Chemistry

Background:

• Antibiotic residues in water pose environmental risks, with livestock manure being a primary source.
• Veterinary antibiotics (VAs) in manure can enter agricultural lands via compost, necessitating VA reduction in composts.

Purpose of the Study:

• To investigate the impact of composting on antibiotic levels in livestock manure.
• To determine how compost components influence the degradation of tetracyclines, sulfonamides, and macrolides.

Main Methods:

• Analysis of antibiotic concentrations in composted materials from manufacturing plants.
• Laboratory-scale composting experiments with pig manure, sawdust, and spiked antibiotics (chlortetracycline, sulfamethazine, tylosin).
• Monitoring of antibiotic levels and physicochemical properties during composting.

Main Results:

• All three studied antibiotics (tetracyclines, sulfonamides, macrolides) declined below Korean guideline values in both field and lab-scale composting.
• The presence of sawdust significantly enhanced the degradation of tetracyclines and sulfonamides.
• Sawdust did not influence the decline rate of tylosin (a macrolide).

Conclusions:

• Composting is an effective method for reducing veterinary antibiotic residues in livestock manure.
• Sawdust inclusion in compost mixtures can improve the removal efficiency of certain antibiotic classes, particularly tetracyclines and sulfonamides.