1. Soil remediation: mechanisms involved

1.1 Removal of various pollutants by soil

The infiltration of domestic wastewater through an unsaturated porous medium—such as most soils—reduces pollution through physical and biological mechanisms:

• suspended solids (SS) by filtration;

• soluble organic matter (carbon and nitrogen) through biological oxidation, adsorption, ion exchange, and precipitation;

• pathogenic microorganisms through complex processes of binding, filtration, inactivation, and predation