CEE 350 - Korshin - Winter 2012 - Quiz 4(1)

CEE 350 - Korshin - Winter 2012 - Quiz 4(1) - Class CEE 350...

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Class CEE 350 Quiz #4 A groundwater contains 80 mg/L Ca 2+ and 45 mg/L Mg 2+ . Find the total hardness expressed in mg/L as CaCO 3 . The atomic weights of calcium and magnesium are 40 and 24.3 g/mol, respectively. The concentrations of Ca 2+ and Mg 2+ expressed in different units are shown below. ±² ±² ±² ±² L meq mg meq L mg EW C L meq Ca Ca Ca / 00 . 4 / 20 / 80 / ±² ±² ±² ±² L meq mg meq L mg EW C L meq Mg Mg Mg / 69 . 3 / 2 . 12 / 45 / ±² ±² L mg EW EW C CaCO as L mg Ca CaCO Ca Ca / 200 50 0 . 4 _ _ / 3 3 u ±² ±² L mg EW EW C CaCO as L mg Mg CaCO mg mg / 184 50 69 . 3 _ _ / 3 3 u The overall hardness of this water is 384 mg/L as CaCO 3 . Write the differential equation defining the efficiency of disinfection and explain its components This is the differential equation for disinfection: N k N kC dt dN n * ³ ³ In this equation, N is the number (or activity) of the pathogens, k is the coefficient of specific lethality, C is the concentration of the disinfectant, and n is an
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CEE 350 - Korshin - Winter 2012 - Quiz 4(1) - Class CEE 350...

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