What is called the raw water that has undergone pretreatment before entering the membrane arrays?

Feed water is the term used to describe the raw water that has undergone pretreatment before it enters the membrane arrays in a water treatment process. This pretreatment is crucial as it helps to remove larger particles, sediments, and other contaminants that could potentially damage the membranes or reduce their efficiency. Properly conditioned feed water enhances the performance of the membrane system by ensuring that only appropriate particles are filtered and allows for optimized operation, ultimately leading to improved quality of the treated water produced.

The other terms do not accurately describe this specific stage of the water treatment process. Input water typically refers to water entering into a system without specification of any pretreatment, while filter water usually describes water that has already passed through a filtration system. Treated water signifies water that has been fully processed and is ready for distribution or use, which comes after the membrane treatment stage.