Phytocapping: a bioengineering technologyto reduce adverse environmental impacts oflandfills especially in arid and semi aridregion

Phytocapping is an alternative capping system which the soil covers and plants are two important components of the phytocapping system. They together play a vital role in the functioning of the phytocapping system. In this system, soil acts mainly as the ―storage‖ to hold and store water and release it to the plants when they need. Soil may also act as a ―screen‖ to restrict methane emitting into the atmosphere and medium for plant survival and growth. In turn plants act as ―bio-pumps‖ to take up the stored water thereby restricting water movement through the refuse and also depleting the soil moisture levels. Plants also act as ―rain interceptors‖ by blocking certain proportion of rainfall from reaching the ground surface via direct evaporation from the plant canopy Plants may also minimize methane escape into the atmosphere by promoting methane oxidizing micro-organisms in the root zone. Both the components (soil cover and plants) work towards maintaining a desirable water balance within the landfill system. Results suggested that phytocaps performed better in semi-arid and arid regions than in the tropical and temperate regions. This study focuses on the old landfill remediation techniques, phytocapping technology and types of it, its advantages and disadvantages rather than the old techniques, used covers in this system, effective factors on phytocap technique, efficiency estimation models of this technique, reasons of high phytocap performance in arid and semi-arid region and ultimately knowledge gap in this field

کلیدواژه ها:

Bioremediation ، Landfills ، Phytocapping ، PlantsSpecies ، Soil Cover