Effects of ceramsite and superphosphate on greenhouse gas and ammonia emissions during green waste composting

To reduce greenhouse gas and NH₃ emissions during the aerobic composting of green waste, this study investigated the regulatory effects of adding ceramsite and superphosphate as additives. The experiment included four treatments: T0 (CK, control), T1 (ceramsite), T2 (superphosphate), and T3 (superphosphate + ceramsite), and a 24-hour continuous aerated system was run for 50 days. The study showed that 46.56%−91.10% of N₂O emissions occurred within the first 10 days, while 87.98%−98.91% of NH₃ emissions were concentrated within the first 5 days. The addition of ceramsite reduced CH₄ emissions by 21.06% and increased the seed germination index by 10.01%. Superphosphate significantly inhibited the emissions of CH₄, N₂O, and NH₃, with reduction rates of 38.58%, 18.18%, and 37.22%, respectively. It also increased the NH₄+-N concentration by 119.73% and promoted the retention of NO₃−-N. The combined addition of ceramsite and superphosphate (T3) enhanced the alkaline hydrolysable nitrogen concentration of compost and further improved the reduction rates of CO₂ and CH₄ to 20.12% and 57.88%, respectively. This study provides a reliable technical pathway for the low-carbon resource utilisation of green waste.