Optimal design of water recovery network with improved operability

Abstract

A suitable water network for any water using process can help reduce the amount of fresh water usage. many researchers have investigated water recovery network for multiple contaminants using mathematical programming. however, operability problems and complex network design have made the actual implementation of the design impractical. in this research, a minlp mathematical model to design new water recovery network with improved operability is presented. the method considers tanks for intermittent streams based on capacity, omitting small flow rates, preferring more economical streams for cost minimization purposes piping reduction. the approach has been successfully implemented for both industrial and urban cases. ccm chemicals has been chosen for industrial case study and sultan ismail mosque in utm as an urban case study. the result shows 17.6% saving on freshwater usage and 53.8% reduction of wastewater generation in ccm chemicals, giving an approximate saving of rm 34,942 per year on freshwater consumption. moreover, 3 tanks have been considered in water system and 18 reuse streams have been removed for simplification of water network. this resulted in reduction of piping requirement for water reuse. for sim case study, freshwater consumption is reduced by 14.56% wastewater generation is reduced by 22.9%. it gives a monetary saving of rm 1,250 per year on freshwater cost. in addition, 2 tanks for intermittent streams are considered and 3 small streams are deleted from the water network. this elimination caused reduction of piping requirement for water network.