A review of mitigating nitrogen losses during composting of organic waste: Insights from a meta-analysis

Nitrogen loss is a critical contributor to nutrient depletion and environmental pollution during composting. A meta-analysis of total nitrogen (TN) loss during composting were conducted in this study, focusing on quantification, influential factors, and mitigation approaches. The results revealed that approximately 29.20% of TN loss occur during composting, mainly as NH 3 -N and N 2 O-N. By analyzing the impact of various composting practices on TN loss, optimal conditions for nitrogen retention were identified. These include starting with a lower initial nitrogen content, maintaining the maximum temperature around 51.7 °C, and setting C/N ratio at approximately 25. Among mitigation strategies, additives most effectively reduced TN loss by 24.59% to 28.53%, while optimized aeration achieved the greatest reductions in gaseous emissions—lowering NH 3 -N and N 2 O-N losses by 52.96% and 46.99%, respectively. The study highlights the need for a combined approach to manage composting operations effectively.