The following figures illustrate some options for treatment systems. Figure 13.29 shows a system where little or no treatment is needed. Figures 13.30 and 13.31 show situations in which progressively more treatment is provided, while Figs. 13.32 and 13.33 show situations in which “hard” treatment solutions with settlement, retention and infiltration tanks are provided in some manner. Sometimes settlement and retention tanks can be entirely fabricated from concrete, on other occasions they can be formed of excavations in soil at a location where settlement of solids onto and in the soil is acceptable as the soil has been carefully selected and prepared to prevent
Fig. 13.31 Environment with extremely high sensitivity
long distance movement of the contaminants (e. g. by the use of soils with a high sorptive capacity that have been carefully compacted as a liner).
The potential of wetlands as treatments (Fig. 13.31) was illustrated in Chapter 12 (see Figs. 12.1 and 12.2) and described in Section 13.3.8.
