Tobacco Waste Residue as the N-source for Composting by Using Negative Pressure Mode Operation

Abstract

The objectives of this research were 1) to apply the tobacco waste residues as major nutrient sources for community-based composting and 2) to investigate the effectiveness of negative pressure mode composting and compost quality for agricultural use of toxic free farming groups of On-Tai municipality, Chiang mai. Two exterior composting piles (1 ton/pile) with dry weight ratio of tobacco waste residues: dry leaves at 300:300 kg (1:1) amended with the organic fertilizer pellets as an inoculum of about 5% per pile (wt,db) were demonstrated. The initial condition of the C/N ratio and moisture content was controlled of 20-25 and 60-65%, respectively. Changes in the physical and chemical properties of the compost were monitored throughout the study (60 days) and the cost-benefit analysis of negative pressure mode composting was also examined. Results revealed that the tobacco waste residues were comprised of high content of the N (3.08%) and organic matter, whereas the content of heavy metals (Pb, Cr, Hg) found was low (<0.05 mg/kg). The performance of negative pressure mode composting rapidly achieved the thermophilic temperatures and leveled off at 61.7-63.0ºC for 36 days. The final quality of compost was acceptable according to the recommended Thai standard criteria regulated by Department of Agriculture of Thailand (2548/2551 B.E.). The application of negative pressure mode composting offers the average production rate of compost of about 12 ton/year (wt,db), while the payback period and the cost per kg-compost are 1.36 year (16.32 month) and 0.75 Baht/kg-compost.