Performance and Biochar Yields of a Closed-Firing Low-Cost Drum-Type Carbonizer for Mahogany and Bamboo Residues

Biodegradable waste constitutes over 50.8% of solid waste streams in Tarlac Agricultural University. This study evaluated the performance and biochar yields of a closed-fired, low-cost drum type carbonizer for mahogany and bamboo residues. The whole system includes a central vertical heat conduit pipe. The furnace has a based enclosure for firing, a firing bed and an ash tray. The carbonizer was fabricated from locally available materials for only 47.13 USD and operated for 3-hour batches using seasoned firewood (25-30 kg Batch ⁻¹ ; 15.5 MJ kg ⁻¹ energy input) also available in the university. The performance of the system was evaluated by operating on 3-hour batch cycles using seasoned firewood. Performance evaluation using a single-factor completely randomized design revealed a biochar recovery yield of 39.33% from bamboo, 36.00% from mahogany shells, and 26.00% from mahogany leaves. The carbonizer operated with highly consistent thermal dynamics across all treatments, showing no significant differences in its specific energy requirement of 0.545 MJ/kg, fuel consumption rate of 8.56 kg/hr, total energy consumed of 502 MJ, and operating time of 3.3 hours. Proximate analysis revealed volatile combustible matter ranging from 66.60% to 93.07%, ash content from 3.40% to 19.80%, and fixed carbon from 3.53% to 13.60%. Higher heating values of 17.09 to 18.43 MJ/kg combined with atomic H/C ratios of 1.49-1.60 indicating a low-temperature slow pyrolysis process of 350-450°C. Bamboo biochar is recommended for soil conditioning, mahogany shell biochar for composting additives, and mahogany leaf biochar as supplemental fuel. This simple design provides a technically feasible, decentralized baseline for green-campus waste management.