Development of a complete process integration framework for wastewater minimisation in batch processes

Abstract

The need for industry to produce the least amount of effluent is greater now than ever. This is due to the fact that environmental legislation is becoming even more stringent and freshwater sources are becoming scarcer. This has prompted research into economic means of reducing the amount of wastewater, whilst still producing the required product at the right quality and quantity. Wastewater minimisation techniques have, in the past, been mainly focussed on continuous type of operations. However, due to the nature of wastewater produced from batch processes, wastewater minimisation in batch processes cannot be ignored. Relatively few methodologies for wastewater minimisation in batch processes have been presented in the past. Those that have been developed are mainly focussed on wastewater characterised by single contaminants and situations where the optimal production schedule is known beforehand. Presented in this thesis are four novel methodologies dealing with four different aspects of wastewater minimisation in batch plants. The four aspects considered are multiple contaminant wastewater, multiple storage opportunities, zero effluent operation and inherent storage within a batch plant. These methodologies together form a complete framework for wastewater minimisation in batch processes. The effectiveness of the methodologies is demonstrated through a number of illustrative and practical applications.