Question

2.) The electrophoretic mobility of colloid particles was measured in a 0.01 mol/dm3 KCI 4 x 10-8 m2/s V. solution and determined to be u Find K fronm the formula K-2.32 x 109 (21)1/2( mrl) (4 points) a. b. For a particle of radius 500nm, what is KR value? (4 points) If KR << 1, ζ 3ηυ/2e, or if KR >>1, then ζ-nu/e. Find the zeta (5) potential in V for particle of radius 500 nm by choosing appropriate formula for Spotential. Use constants: Water viscosity at 25 °C is 1 mPa.s. The 0.01M KCI salt solution's dielectric constant, e c. 78.54 εο, where εο (electric permittivity of vacuum) 8.854 x 10-12F/m. (6 points)

Answer 1

Perform a mass balance at the outfall

Q_upstream = 12-0.5*(3.8) = 10.1 cfs

BOD_upstream = 2.5 mg/L

DO_upstream = 8.5 mg/L

Q_WW = 3.8 cfs

BOD_ww = 35 mg/L

DO_ww = 5.5 mg/L

And immediately after the point of mixing:

Q_outfall = 10.1 cfs + 3.8 cfs = 13.9 cfs

BOD_outfall = ((2.5 mg/L * 10.1 cfs) + (35 mg/L * 3.8 cfs))/13.9 cfs = 11.38 mg/L

DO_outfall = ((8.5 mg/L * 10.1 cfs) + (5.5 mg/L * 3.8 cfs))/13.9 cfs = 7.68 mg/L

D_outfall = 9.5 mg/L – 7.68 mg/L = 1.82 mg/L