Journal of Pure and Applied MicrobiologyVol. 8 No. Special Edition Nov. 2014

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

Ahmed Ismail Khalil1,2*, Fahad Nasser Alkoaik1, MajdiAli Al-Mahasneh1,RonnelBlanqueza Fulleros1 and Ahmed Mohamed El-Waziry3

1Department of Agricultural Engineering, College of Food and Agriculture Sciences, King Saud University, Saudi Arabia. 2Department of Environmental Studies, Institute of Graduate Studies and Research, University of Alexandria, Alexandria, Egypt. 3Department of Animal Production, College of Food and Agriculture Sciences, King Saud University, Saudi Arabia.

Received on 10 August 2014 and accepted on 06 September 2014



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 the mixture 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 m3. Airflow was supplied at a rate of 10 L/min. The results showed that the temperature increased and reached its maximum(54oC) after 36 hrs and then decreased to 26oC. 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 erectusresidues into compost if the optimum conditions are performed.

Keywords : Composting; Conocarpus erectus residues; Evaluation parameters.