Environmental Engineering Reference
In-Depth Information
Chapter 13
Retention and Transfer of Soluble Chemical
Pollutants: Mechanisms and Numerical
Modeling
-
13.1. Introduction
In this chapter we consider the retention and transfer phenomena of soluble
chemical pollutants in soils. More specifically, we are interested in species that are
likely to migrate within the soil and/or get fixed to it without any significant change
in flow conditions. The substances considered are not a phase as such, they are
present in solid and fluid(s) phases. We exclude substances which, because of their
nature and/or their concentration, would form a separate phase of the main fluid
(usually water). Some examples of components that fall within the scope of this
chapter are: nitrate resulting from various fertilizers in widespread intensive
agriculture; salts in aquifers near the coast or from the brine industry; radionuclides
from nuclear waste storage sites; some hydrocarbons at very low concentration, etc.
Hydrocarbons at higher concentration form a separate phase. They are initially
present as separate
bubbles
and then form a continuous fluid phase at higher
concentration. They will not be considered in this chapter.
