Sodium Hex is fed by the ROWPU chemical feed pump at the?

The correct choice is based on the specific operation of a Reverse Osmosis Water Purification Unit (ROWPU). Sodium Hex, or sodium hexametaphosphate, is typically used in water treatment processes as a sequestrant to prevent precipitation and scaling, particularly on reverse osmosis membranes.

In the context of a ROWPU, the chemical feed pump introduces Sodium Hex into the water treatment system at the multimedia filter influent. This is the point where source water enters the multimedia filtration stage, allowing the chemical to mix with the water prior to filtration. This early introduction of the chemical ensures that it can effectively interact with any impurities or hardness in the water, helping to improve the performance of the subsequent filtration and reverse osmosis processes.

When Sodium Hex is fed at this stage, it aids in maintaining operational efficiency by minimizing scale formation and enhancing the overall filtration efficiency before the water reaches the RO elements. This usage is consistent with the goals of maximizing water quality and equipment lifespan, making it a crucial step in the ROWPU process.