Optimal methodology for water recycling and reusability of multiproduct batch plant

Abstract

Multiproduct batch plants are seriously affected by improper production schedules and inefficient wastewater handling. These batch process industries consume massive amounts of fresh water for process and multiple washings of process equipment. Primary objective of the present work is to minimize freshwater intake through proper handling and reuse of wastewater. This paper proposes an optimal methodology of wastewater recycle to address the environmental and economic issues. We explore the possibility of recycling reusable water before sending it to Effluent Treatment Plant (ETP) for treatment. We formulated a constraint, mixed integer non-linear programming (MINLP) optimization model, to simultaneously address environmental and economic issues for a multiproduct batch plant. The model applied to a process involving multiple washes and multiple storage tanks having pre-specified concentration limits. This model provides the amount of recyclable wash water, overall freshwater demand and effluent generation. The reported case study suggests that the freshwater reduction is in the range of 40–60%. We also performed dynamic simulations using the MATLAB-GAMS interface to monitor dynamic variation in the height of waste water in segregation tanks due to dynamic variation in wash water generation.