Reduction of water consumption in an integrated first- and second-generation ethanol plant

Results show that external withdrawals of 738 L/t of cane for Case I, 955 L/t of cane for Case II and 853 L/t of cane for Case III are required to cover the water deficit of the plant. These values are lower than the mandated limit of 1000 L/t of cane for the sugar cane industry in the State of São Paulo. Moreover, for Cases II and III, which need large additional amounts of water for the hydrolysis stage, water usages of 10.77 and 9.38 L of water per litre of ethanol produced were achieved, approaching the figure of 9.34 L water per litre of ethanol produced by the conventional plants (Case I). This highlights the high potential for reduction practices based on the concept of energy and water integration.