Application Note

Technical Note: Using 3M Liqui-Cel Membrane Contactors To Solve Resistivity Problems In A High Purity Water Loop

Source: 3M Separation and Purification Sciences Division

Pureflow, Inc. is a Southeastern-based expert in designing complete water treatment systems as well as providing value-added solutions for fixing operational issues in existing systems. Pureflow teamed up with Membrana to help solve an operational issue at one of their customer’s facilities.

The existing high purity system consisted of a pre-treatment skid that supplied the feed stream for a 5 gpm reverse osmosis (RO) system. Product water from this RO system flowed to a 5 gpm electrodeionization (EDI) unit. Effluent from the EDI system went to a storage tank before moving to an ultra-violet light, and then to the resin-based deionization tank. The effluent then passed through final filtration before entering the facility’s water loop.

Water fed to the facility was expected to be high quality ultra pure water with consistent effluent properties. One of the desired parameters of the product water was to have a resistivity reading of 18.0 M-ohm/cm or better. Measurements taken of the post-EDI water stream, however, showed resistivity ranging from a low of 1.0 M-ohm/cm to only 13.7 M-ohm/cm. Additionally, the readings were very inconsistent and erratic.