Use of cooling tower blow down in ethanol fermentation

Reducing water consumption in bioethanol production conserves an increasingly scarce natural resource, lowers production costs, and minimizes effluent management issues. The suitability of cooling tower blow down water for reuse in fermentation was investigated as a means to lower water consumption. Extensive chemical characterization of the blow down water revealed low concentrations of toxic elements and total dissolved solids. Fermentation carried out with cooling tower blow down water resulted in similar levels of ethanol and residual glucose as a control study using deionized water. The study noted good tolerance by yeast to the specific scale and corrosion inhibitors found in the cooling tower blow down water. This research indicates that, under appropriate conditions, reuse of blow down water from cooling towers in fermentation is feasible.