Abstract
For in-vessel composting of garden waste, the selection of reactor is an important factor for efficient degradation. The present study evaluates working performance of rotary drum reactor (RDR) and aerated in-vessel (AIV) for composting of garden waste. 100 kg garden waste was mixed with 10 kg cow-dung slurry and 5 kg compost and feed into both the reactors for 45 days composting period. The reactors vary in their system configuration, shape and orientation, blade design, rate of aeration, odour control, leachate production and energy requirements. Rotary drum was rotated daily six times in clockwise and anti-clockwise direction and AIV was rotated daily for 3–5 minutes using motor. Rise in temperature started within 24 hours of composting and reached 65°C and 59°C on second day itself and thermophilic phase continued for 7 and 5 days for RDR and AIV respectively. Moisture content reduction after composting period was 15.25 and 18.45 %, C/N ratio was 16.14 and 13.33, TVS reduction was 23.74 and 29.78 % and CO2 evolution rate was 6.18 and 4.14 mg/g VS/day in RDR and AIV respectively. Reduction of hemicellulose, cellulose, and lignin was more in AIV. The percentage reduction of acid insoluble lignin was 36.10 and 29.01 % and the percentage reduction of acid soluble lignin was 48.85 and 43.3% in in AIV and RDR respectively after 45 days. AIV gave better performance for composting of garden waste.