The MixAlco process converts biomass into organic chemicals and alcohols via lime pretreatment; non-sterile, acidogenic digestion; product concentration; thermal conversion and hydrogenation. Because they have low capital costs and relatively simple operation, it is proposed that the pretreatment and fermentation steps of the process may be suitable to be carried out on-location at confined animal feeding operations or municipal landfills. This project investigates converting dairy manure and chipped yard waste into carboxylic acids using a counter-current fermentation system and a solid state percolation system, respectively.

The counter-current pretreatment and digestion system was constructed on a dairy farm in Central Texas and operated for several months to determine the effectiveness of on-site conversion. The system consists of five plastic barrels that serve as both pretreatment and fermentation reactors. The setup is configured with a series of pumps to transport liquids from barrel to barrel enabling the counter-current fermentation system. The application of a percolation system for solid state conversion of particulate biomass is being investigated using chipped yard waste as a model substrate. The percolation experiment is carried out in a 6 foot plastic column reactor that is capable of performing both the pretreatment and fermentation steps. Initial conversion results for both the counter current and percolation systems are presented.