RESUMEN
Nutrition components and elements analysis of spent mushroom substrates/composts (SMS/SMC) during a cyclic utilization were performed to state the compositional variation during reutilization and composting process. Environmental risk assessment of heavy metals and other pollutants were also taken into consideration. The results showed that the water consumption during reutilization reached 13.8%; while the protein and polysaccharide contents increased by 32.9% and 20.4%, respectively, suggesting that SMS still had a lot of nutrients. After composting disposal, however, the protein and polysaccharide contents decreased by 50% and 79%, respectively, while the lignin, cellulose and hemicellulose contents didn't show a significant difference; the C/N ratio decreased; the total humic acid content increased by 18.6%, all of which means that the composting process made great contributions to organic degradation. The heavy metal analysis showed that As, Hg, Pb, Cd, Cr concentrations in organic compost met the requirement of limit standard (NY525-2012). In addition, the results of column leaching test showed that N, P and organics in both SMS and SMC had a possibility of leaching loss, and the accumulation of TN and COD in SMC leachate decreased by 15.0% and 62.8%, respectively, compared to SMS group.