WASTE-WATER MINIMIZATION

This paper addresses the minimisation of wastewater in the process industries. Targets are first set which maximise water re-use. The approach used allows individual process constraints relating to minimum mass transfer driving force, fouling, corrosion limitations, etc. to be easily incorporated. Both single and multiple contaminants are addressed. The multiple-contaminant case allows multiple constraints relating to the multiple contaminants to be allowed for. Water regeneration opportunities are also identified at the targeting stage which distinguish between re-use and recycling. Two simple design methods are presented which allow targets both with and without regeneration to be achieved in design. The first design procedure maximises driving forces in individual processes whilst the second minimises the number of water sources for each process. The approach adopted is entirely conceptually based.