Effect of enforced aeration on in-vessel food waste composting

A laboratory composting was conducted to determine the effect of the contin uously enforced aeration on the composting performance. The mixture of dog food, excess sludge, and woodchip was used as raw composting materials. The temperature changes in the decomposition process, and pH, weight loss, ash , and extract composition from the final product after 17 days composting w ere investigated. The results demonstrated that flow rate of enforced aerat ion indeed influenced the composting performance. Composting under 0.05-0.1 l min(-1) condition seemed better than that under 0.2-0.4 l min(-1) condit ion. Higher flow rate of air not only cooled the composting mixture signifi cantly, further adversely affected temperature rise, but also evaporated mo isture mostly. Thermophilic composting can occur under 0.05-0.11 min(-1) ai r flow rate condition, while composting in cases of 0.2-0.4 l min(-1) air f low rate mainly resulted in a mesophilic process. Microbial activity was co nsidered to be significantly inhibited at 0.4 l min(-1) air flow rate condi tion based on the analyses of total organic carbon and volatile fatty acids from water extraction of composting products.