Pretreatment Technology for Ethanol Fermentation Broth from Food Waste

Ethanol fermentation from food waste could reduce environmental pollution and obtain high-value product. Distill was used as the major way for ethanol separation, but it had the drawback of high cost. In these days, pervaporation was considered as the best substitute to distill because of its low energy consumption. However, the ethanol fermentation broth from food waste, particularly the high oil and SS concentration in them, could not meet the requirement for pervaporation. This article investigated the pretreatment technology for broth. Flocculation-filter technology was determined as the choice and corresponding optimum conditions were studied. The gelatin was the best coagulant. The optimum conditions were determined as pH=9, dosage of 0.8 g/L, mixing time 5 min, stirring speed 800 r/min, temperature 40 degrees C. The removal rate for SS and oil were 83.8% and 36.67% respectively after flocculation. Then the outlet was purified by complex filter column made by fiber ball and sand filter. Corresponding concentrations of SS and oil decreased from 3.04g/L and 18.53g/L to 0.58g/L and 0.16g/L, respectively. The ethanol concentration was not affected by such treatment. The final outlet could meet the requirement for pervaporation.