A Lumped Parameter Heat Transfer Analysis for Composting Processes With Aeration

Composting is the biological decomposition and stabilization of organic substrates. Heat is generated biologically to produce a final product that is stable, free of pathogens and weed seeds, which can be beneficially applied to land. As pointed out by Haug (1) and Li and Jenkins (2), composting is an ancient art, yet engineering that is still often conducted using a “handbook approach.” However, such an approach lacks the knowledge to control various factors involved to achieve the desired end product and economics. A typical composting system with aeration is shown in Fig. 1, where the air is ventilated from the bottom to accelerate the biological processes. The air carries sensible and latent heat away as passing through the matrix, while it is essential to maintain organic decomposition leading to biological heat generation. Thus, the control of aeration requires heat transfer analysis if we are to...