Remediation and Management of Contaminated Soil - Sustainable Practices in Geoenvironmental Engineering - page 404

Determine contaminants and
site characteristics

Identify management
alternatives

Laboratory tests

Evaluate and compare risks
from different alternatives

Predictive fate and
transport modeling

Pr
tr

Determine and develop remediation
scheme and required monitoring and pilot
testing

Achievement of
remediation plan

Execute remediation and
monitoring scheme

No Yes

Are remediation objectives achieved?

FIGURE 11.1
Flowchart demonstrating development of a program to ensure achievement of remediation objectives.

in Chapters 3 and 10, respectively, and will not be repeated here. The discussion in this
chapter will focus on in situ and ex situ techniques in soil and sediment remediation.

11.2 Physical Remediation Technologies
Two options are available for disposal of contaminated soil: (1) disposal in a secure landill
or disposal facility and (2) treatment of the contaminated soil and reuse of the treated soil.
Option (1) is not a preferred option as it is not sustainable. Treatment of contaminated soil
can be an expensive procedure, especially when the quantities are large.

11.2.1 Isolation

Contaminated soil can be isolated to prevent further movement of the contaminants. This
management scheme is usually of low to medium cost. Steel, slurry, cement, or bentonite
barriers and grout walls and synthetic membranes can be used singly or in combination
to reduce the permeability of the soil to less than 10 −7 cm/s. They are considered as passive
containment systems and can be temporary to complement remediation systems or be per-
manent. Vertical or horizontal barriers or capping are modes of reducing the movement.
Vertical barriers should extend (or be keyed in) to an impermeable clay or bedrock layer