Applying Effective Microorganisms to Optimize Municipal Composting Systems: A Pilot Implementation in Serbia

This study evaluates the application of Effective Microorganisms (EM) in large-scale municipal composting under real operational conditions in Serbia. A controlled field experiment was conducted over a 90-day composting period to compare EM-treated and untreated windrows of urban green waste. Key compost quality parameters were assessed to determine compost maturity and nutrient status. EM application resulted in improved compost properties, with stabilized pH (7.28 ± 0.12), increased humus content (26.52 ± 1.10%), higher total nitrogen (1.33 ± 0.05%), available phosphorus (133.46 ± 5.20 mg/100 g), and potassium (226.00 ± 8.50 mg/100 g), as well as a reduced C/N ratio (20.0 ± 0.9) compared to the control. These results indicate accelerated organic matter decomposition and enhanced compost maturation in EM-treated systems. The findings demonstrate that EM technology can improve compost quality and process efficiency in municipal composting, supporting its practical application within sustainable urban organic waste management frameworks.