AWWA JAW26388

In 1976, a Florida-based equipment manufacturer conceived the idea of using modified reverse osmosis membranes instead of lime softening to treat waters with low total dissolved solids. The authors of this article assess the progress made over the last 10 years in the field of membrane softening or nanofiltration technology, concluding that the process is competitive with conventional treatment but cautioning that it should be evaluated on a case-by-case basis. The contention that membrane softening is worthy of consideration is supported by historical records of existing membrane softening plants, successfully completed pilot studies, and acceptance by regulatory agencies. Use of the membrane softening process should be considered whenever a treatment plant expansion is being evaluated. Process costs are briefly discussed. Includes 20 references, tables, figure.