Sustainable Food Processing Systems- Path to a Zero Discharge: Reduction of Water, Waste and Energy

摘要

Food processing systems consume extensive amounts of water and energy. However, due to limited availability of resources, restrictions on biological pollutants and increasing cost for waste treatment the food industry has the incentive to reduce water/energy consumption and wastewater generation with the goal of developing a zero discharge process that utilizes substantially less water and energy and generates no waste. The objective of this study is to evaluate water and energy consumption in the food process systems and to propose alternatives that reduces water and energy demands in the processing of three food products; 1) edible bean, 2) dairy products, and 3) corn masa. Three main approaches were used to evaluate the selected processes; 1) plant-scale audit data collection to determine energy consumption, 2) laboratory scale experiments to assess product quality changes with a drastic reduction in water and energy usage, and 3) a process simulation using computer-aided tools to design systems for reduced water and energy consumption and wastewater generation. The results suggest that a zero discharge food process is feasible by drastically reducing water and energy consumption. Modifications to the edible bean process reduced water input up to 55% and wastewater generation was decreased up to 91%. Various process and heat recovery options for the dairy plant were evaluated and the optimal option could economically decrease the boiler fuel requirement by 50 times, and reduce the operating cost to 2.7% of the present cost. The redesigned corm masa process was able to significantly reduce water usage, wastewater, and energy consumption compared to the traditional process. The water reuse process resulted in 90% reduction in the amount of wastewater and a 55% reduction in the amount of water used during processing. The amount of energy required for heating was saved by 70% in the water reuse process. When scaling-up to plant-scale, reusing water could reduce water consumption by 95% and reduce energy requirement by about 80%.