Material and energy balances in a large-scale aerobic bioconversion cell

Abstract

On the basis of earlier experimental studies of the aerobic bioconversion of organic,wastes, the preferred values of operating parameters, and the biochemical rate constants of oxidation to CO2 and H2O were identified. Energy and material balances were then constructed for a large, 3 in deep aerobic cell holding 1,440 tons of the 'wet' component of organic wastes (major organic constituent: [C(6)H(10)O(4)l(n)). It found that conduction convection bind radiation losses to the surroundings amount to a relatively small fraction of the chemical heat released by oxidation. Therefore, the surplus, chemical heat must be removed by means of an upward water-saturated air flow that is several-fold the stoichiometric requirement for biodegradation. This study has quantified a basic process difference, between anaerobic and aerobic bioconversion of organic matter: In the former, most of the chemical energy in the converted organic matter is stored chemical in the generated methane gas. In the latter, this energy is released in the cell and must be carried Out in a relatively larvae air/water vapour through the cell.