Water budgets for natural systems

Abstract

Natural systems including constructed and natural wetlands as well as irrigated land areas,
geofilters and ponds are capable of absorbing pollutant loadings, and in appropriate
circumstances can provide a low cost alternative to traditional chemical and biological
treatment. Many projects have shown reduction of nutrients, oxygen consuming substances
but also more environmental haz.ardous compounds.
Natural systems seem to have a great potential for treatment of leachate. Some parts of these
systems belongs to biological treatment and other parts to "filtration" and therefore these
systems could be seen as a mix of transformation and filtration together with the volume
reducing effect by evaporation and transpiration. Method used in Sweden are mainly SoilPlant (SP) system there a large part of the treatment is removal of water by evapotranspiration.
Irrigation of e.g. energy forest or land surfaces increases the possibility of natural evaporation.
When an area of the landfill is irrigated the water balance will change. This paper focuses
upon the water budget and water movement within the natural system.