Little is known about the power requirements of the exhaust fan throughout the composting period of a forced aeration systems. This study was conducted in order to adjust the variation curves for static air pressure, when forced into piles of organic material at different biochemical degradation stages. To that end, a composting pile with both sugarcane bagasse (BC) and poultry litter (CF) was stacked, by preparing the mixture in such a way as to obtain an initial C/N ratio of 30/1. The material was revolved every three days during the first month, followed by revolutions at regular 5-day intervals for two more months. Load loss was measured at 1m column height for the BC under the same conditions used in the mixture, as well as in the BC + CF mixture under the conditions at 30, 60 and 90 days of composting. The higher the specific air flow and the biochemical degradation time of the material under composting, the higher the decrease in the static pressure of the air insufflated in it. The Shedd model was well adjusted to the experimental data in the air specific flow range under investigation, and can be used to predict the static pressure gradients in organic compost.
composting; aerated static piles; aeration