Water Efficiency in Industrail Projects

We are constructing a large expansion to a dairy products manufacturing plant which the owner desires to certify. Both ourselves (CM) and the design team are concerned about the projects ability to meet WE PR1. To us, the reference manual is less than clear as to how we must treat process water. This is significant as the process water is 90%+ of the total water usage. This is a regulated facility so there are limitations on the techiques that can be employed. Can anyone share any experiences with similar situations Thx