Effect of lime and calcium magnesium phosphate on gaseous emissions, maturity, and bacterial dynamics during food waste composting

This study estimated the effects of 0.5–1.5% lime and 10% calcium magnesium phosphate fertilizer (CaMgP) addition (dry mass) on maturity, gaseous emissions, and bacterial dynamics during food waste composting. The 1.0% and 1.5% lime amendments accelerated the proliferation of Thermobifida and Saccharomonospora for a higher germination index. The growth of methanogens (e.g., Tepidimicrobium and Caldicoprobacter) and Bacillus was restrained by additives to reduce the methane (CH4) and ammonia (NH3) emissions, respectively. Lime and CaMgP also limited denitrification by increasing pH, resulting in lower nitrous oxide (N2O) emissions. In detail, the highest decrease in N2O (59.35%) and hydrogen sulfide (H2S, 22.21%) emissions were observed in the 10% CaMgP group. The 0.5–1.0% lime treatments exhibited the highest alleviation in CH4 (80.77%) and NH3 (39.85%) emissions. Nevertheless, 1.5% lime addition promoted bacterial abundance in S cycle for a higher H2S emission.