Keywords: co-composting, shredded paper, broiler litter, windrows, temperature, respiration rate, volatile solids, wastepaper, composting, waste management
Windrow co-composting of shredded office paper and Broiler Litter
The co-composting of shredded waste office paper with Broiler Litter (BL) in windrows was analysed in this study. Two compost mixes were monitored for five weeks; Mix 1 comprised 322kg BL, 117 kg shredded paper and 310L water and Mix 2 consisted of 112 kg BL, 265 kg shredded paper and 290 L water. The initial wet moisture content, initial porosity and initial wet bulk density for Mix 1 were 54.6%, 74.7% and 337kg/m?, respectively. The respective parameters for Mix 2 were 48.6%, 87.7% and 185 kg/m?. The initial C:N ratio was kept at 20.8 in both mixes. Peak temperatures recorded for Mix 1 and Mix 2 at day 5 were 71.4?C and 62.7?C, respectively. Temperatures remained above 60?C for more than 10 days in both windrows. The pH for both mixes varied between 7.2 and 8.8. An increase in wet bulk density of 47.6% for Mix 1 and 150% for Mix 2 was obtained. The net decrease in Volatile Solids (VS) was of 57.1% (Mix 1) and 56.3% (Mix 2) at the end of week 5. The respiration rate peaked at 33.7 mg CO2.C/day.gVS on day 3 for Mix 1 and decreased to 0.98 mg CO2.C/day.gVS on day 37. The concentrations of lead, cadmium, total chromium and zinc were 612 mg/kg, 60.8 mg/kg 103.2 mg/kg and 5760 mg/kg, respectively, in the final compost of Mix 1. NPK content of the final compost from Mix 1 was 5-5-10 (dry matter basis) with a level of phosphorous of 20,817 ppm.