1、Designation: D4582 10Standard Practice forCalculation and Adjustment of the Stiff and Davis StabilityIndex for Reverse Osmosis1This standard is issued under the fixed designation D4582; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisio
2、n, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers the calculation and adjustment ofthe Stiff and Davis Stability Index (S decreasing
3、 the calcium andalkalinity concentrations; or by changing the ratio of totalalkalinity to free carbon dioxide in the feedwater.5. Significance and Use5.1 In the design and operation of reverse osmosis installa-tions, it is important to predict the calcium carbonate scalingproperties of the concentra
4、te stream. Because of the increase intotal dissolved solids in the concentrate stream and the differ-ences in salt passages for calcium ion, bicarbonate ion, and freeCO2, the calcium carbonate scaling properties of the concen-trate stream will generally be quite different from those of thefeed solut
5、ion. This practice permits the calculation of the S however, since many variables changewith acidification, trial and error computations are required todetermine the amount of acid needed to determine the amountof acid needed to obtain the desiredS membrane scaling; reverse osmosis(RO); stability index for RO; Stiff and Davis Stability Index (Sor through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).FIG. 3 Conversion of Calcium and Alkalinity to pCa and pAlkD4582 104
