COOLING COOLING TOWERS NANOFILTRATION REVERSE OSMOSIS SCALING REUSE WASTEWATER

Download Full Article

Abstract

Saturation and scaling indices have been used in the water treatment industry since Professor W. Langelier first published his famous Langelier Saturation Index (LSI) in 1936 (1). In the ensuing years, industrial endusers of water came to the realization that the LSI was overly conservative when applied to industrial applications such as cooling towers. That is, the LSI would frequently predict scale formation in an industrial water system when in reality, no scale would form. For this reason, the LSI has been deemed a poor tool for predicting calcium carbonate deposition in industrial water systems. The amount of conservatism built into scaling indices and saturation ratios can be thought of as ﾓover-estimationﾔ of scale, or as a ﾓsafety marginﾔ, the cost of which is increased water consumption as well as increased cost of equipment and chemicals to treat the water to prevent scale. It is not uncommon for chemical suppliers to indirectly recommend a very generous safety margin by stipulating that the LSI be used for predicting calcite scale formation. In such cases, the overly conservative LSI leads to an unjustified over-dose of chemical inhibitor, when in fact, a lower dosage, or no product at all would not result in scale formation.

Log in or Subscribe to Access the Full Article

To read or download full-length articles you need a subscription to Ultrapure. Please log in or subscribe below.