Water management methods in food industry: Corn refinery as a case study

Abstract

Water pinch analysis and mathematical optimization are two approaches that can be used in an industrial unit to achieve the minimum water consumption and wastewater generation flowrates. The fundaments of these approaches are based on water reuse. In this study, water pinch analysis and mathematical optimization studies are conducted in a corn refinery to achieve minimum targets. COD and TDS were separately considered as single limiting contaminants in water pinch analysis and water network of a corn refinery plant was modified. Water consumption in the studied corn refinery decreased from 1800 m3/day to 1235 m3/day if COD was taken into account and to 1152 m3/day if TDS was. The same results are achieved for single contaminant in mathematical optimization as well. The single contaminant approaches in the most cases are useless due to process limitations in water reuse. Therefore, mathematical optimization with multi-contaminants approach is conducted to design a reasonable water distribution network. Simultaneous consideration of COD and TDS in a multi-contaminants optimization resulted in 30% decrease in water consumption and required freshwater was reduced to 1260 m3/day.