Page 79 - Materials Chemistry, Second Edition

62 Practical Design Calculations for Groundwater and Soil Remediation

solid phases). The values of the dimensionless Henry’s constant for benzene
and pyrene are 0.22 and 0.0002, respectively. The values of K for benzene
p
and pyrene are 1.28 and 717, respectively.

Strategy:
A computer spreadsheet, such as Microsoft Excel, is a good way to solve
a problem such as this.

Solution:
Basis: 1 m of soil
3
(a) Determine the mass in the void

Benzene Pyrene
MW 78 202
G (ppmV) 100 0.01
G (mg/m ) 324.3 0.084
3
Air void (m ) = 0.40 × 0.7 0.28 0.28
3
Mass in void (mg) 90.8 0.024
(b) Determine the mass dissolved in the liquid

Benzene Pyrene
H 0.22 0.0002
C (mg/m ) = G/H 1,474 420
3
Liquid volume (m ) = 0.40 × 0.3 0.12 0.12
3
Mass in liquid (mg) 176.9 50.4
(c) Determine the mass adsorbed onto the solid

Benzene Pyrene
1.28 717
K p
C (mg/L) 1.47 0.42
S (mg/kg) = K p × C (mg/L) 1.89 301
3
Soil mass (kg) = (1 m )(ρ b ) 1,600 1,600
Mass on solid surface (mg) 3,019 4.82 × 10 5

(d) Determine the total mass in three phases

Benzene Pyrene
Total COC (mg) 3,287 4.82 × 10 5