Towards Sustainable Water Usage in a Beverage Plant

Abstract

The current drive towards environmental sustainability and the rising costs of freshwater and effluent treatment have forced the process industry to reduce freshwater consumption and wastewater generation, which can be achieved inter alia by water re-use. The mathematical models presented in the literature need to be modified in order to match industrial circumstances. This paper presents a mathematical model for water re-use in batch processes in the presence of continuous streams with acceptable purity. The model is based on a design method developed by Kim and Smith, modified to properly balance continuous streams. Continuous streams are treated as limited freshwater sources. Two cases were analysed: 1) re-use of continuous streams within those time intervals where the continuous streams exist, 2) re-use of continuous streams in later time intervals with intermediate storage of unused continuous streams. The opportunities of water re-use by the developed model were analysed in a brewery plant. By using the identified re-use connections, the brewery could save about 18% of its current freshwater demand.