Physical, Chemical and Microbial Changes during the Composting of Conocarpus erectus Residues

摘要

Changes in physical, chemical and microbial parameters were monitored during the composting of Conocarpus erectus residues using a bioreactor. The residues (leaves and small stems) were collected, cut into small pieces and mixed. The C/N ratio of themixture was 25.22. The moisture content was adjusted to 65% at the start of the experiment.The total volume of the bioreactor was 0.03 m~3. Airflow was supplied at a rate of 10 L/min. The results showed that the temperature increased and reached its maximum (54"C) after 36 hrs and then decreased to 26“C. The final compost was odourless and black. The pH decreased from 6.50 to 6.35 after 3 days and then increased to 6.83. The electrical conductivity increased with time from 1.77 to 2.09 mS/cm. The organic matter decreased from 83.93 to 75.85% and the loss reached to 39.86% and followed the first-order kinetic equation. The C/N ratio decreased from 25.22 to 18.48. The mesophilic bacteria and fungi decreased after 3 days and then increased, whereas the thermophilic ones increased after 3 days and then decreased. It can be concluded that composting can be a suitable method for converting Conocarpus erecfusresidues into compost if the optimum conditions are performed.