In order to simplify the superstructures of water networks to obtain their solutions

an approach to water network design by using genetic algorithm (GA) based on the criterion of maximal water reuse was proposed.In this method

the superstructure of water network was simplified according to the monotony of outlet concentration of each process.When the inlet concentration or the outlet concentration reached its maximum constraint

the fresh water usage was determined.The minimum fresh water usage of water network was taken as the optimal objective

the internal flow rate and waste water flow rate of each process were selected as the genes.This simplified water network was optimized by using GA.The coding in GA was the floating point number coding

the arithmetic cross technique and the cross technique among different groups were used.Case studies showed that this method worked well

the water networks could be simplified by using the criterion of maximal water reuse and the solution of global optimum of water network could be obtained by applying GA.