Question

4. Use the table below to calculate the following: The concentration (in mg/L and moVL) of the coagulant (AISO)) in the stock solution The coagulant feed rate (in Lday) required to achieve target concentration The alkalinity consumed by coagulant addition (in mg/L as CaCO,) Coagulant Plant Flow Dose(mg/L)-|-(mgd) Stock Coagulant Chemical ConcentrationS Coagulant pee.Gravity 1.28 Aluminum Sulfate (Alum) 6.5 21 26% AldS( )4 ) 1014H20

Answer 1

Calculate the formula weights (FW) for Al_2O_3 and Al_2(SO_4)_3.14H_2O Take molecular weight of Al = 27 g/mol, O = 16 g/mol, and H = 1 g/mol. 1. FW: Al_2O_3 = 2(27) + 3(16) = 102 g/mol 2. FW: Al_2(SO_4)_3.14H_2O = 2(27) + 3(32) + 26(16) + 28(1) = 594 g/mol (1) Calculate the stock alum concentration as g/L of Al_2(SO_4)_3 14H_2O: a. Calculate the density of stock chemical. rho_stock = SP times rho_std = 1.28 times (1 kg/L) rho_stock = 1.28 kg/L b. Calculate the concentration of alum in the stock chemical as g/L Al_2O_3. C_stock = C% times rho_stock = 26/100 times (1.28 kg/L times 10^3 g/1 kg) C_stock = 332.8 g/L of Al_2O_3 c. Calculate the stock alum concentration as g/L of Al_2(SO_4)_3.14H_2O C_stock = 332.8 g/L of Al_2(SO_4)_3.14H_2O (2) Calculate the coagulant feed rate: a. Change the plant flow from mgd to m^3/d. F = 21 mgd times 3785.4118 m^3/day/1 mgd F = 79.49 times 10^3 m^3/day