Recovery of fermentable sugars from process vegetable wastewaters

Abstract The U.S. fruit and vegetable processing industry annually generates approximately 11 million t of byproduct wastes along with over 430 × 10 9 l of effluent wastewaters. Appropriate disposal of these wasteflows is a costly burden to the generating industries. By selective processing of certain of these wasteflows through reverse osmosis (RO) facilities, approximately 1.42 million t of fermentable sugars could be recovered as a 20% sugar concentrate suitable for bioconversion to useful liquid fuels. The annual fuel alcohol potential of these sugars is between 750 and 900 million l. Economic analysis indicates that overall alcohol production costs should average only 40% of current FOB prices for U.S. bulk fuel alcohol. The coincident major reduction in wastewater BOD and associated disposal cost, and the recovery of over 43 × 10 9 l of reusable RO permeate water afford added incentives for industrial participation in the production of sugar concentrates from fruit and vegetable byproduct wasteflows.