Full Description

Many membrane element manufacturers provide a computer program to aid buyers in the useof their elements. However, to date there are few examples of fully integrated public domainsoftware available for calculating reverse osmosis and nanofiltration system performance. TheTotal Flux and Scaling Program (TFSP), written for Excel 97 and above, provides designers andoperators new tools to predict membrane system performance, including scaling and foulingparameters, for a wide variety of membrane system configurations and feedwaters.The TFSP development was funded under EPA contract 9C-R193-NTSX. It is freelydownloadable at www.reverseosmosis.com/download/TFSP.zip. TFSP includes detailedcalculations of reverse osmosis and nanofiltration system performance. Of special significance,the program provides scaling calculations for mineral species not normally addressed incommercial programs, including aluminum, iron, and phosphate species. In addition, ASTMcalculations for common species such as calcium sulfate (CaSO4 . 2H2O), BaSO4, SrSO4, SiO2,and LSI are also provided.Scaling calculations in commercial membrane design programs are normally limited to thecommon minerals and typically follow basic ASTM methods, which are for the most partgraphical approaches adapted to curves. In TFSP, the scaling calculations for the less commonminerals use subsets of the USGS PHREEQE and WATEQ4F databases and use the samegeneral calculational approach as PHREEQE and WATEQ4F. The activities of ion complexesare calculated iteratively. Complexes that are unlikely to form in significant concentration wereeliminated to simplify the calculations. The calculation provides the distribution of ions and ioncomplexes that is used to calculate an effective ion product "Q." The effective ion product isthen compared to temperature adjusted solubility products (Ksp's) of solids in order to calculatea Saturation Index (SI) for each solid of interest. The SI is expressed as a log value (log(Q) -log(Ksp)) where positive values indicate potential scaling conditions. As this is an unprotectedspreadsheet, the methodology is plainly visible to and readily modified by the user. Includes 10 references, figure.

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Edition: Vol. - No. Published: 05/01/2001 Number of Pages: 13File Size: 1 file , 290 KB