Wetlands are nature’s best water filters – giant kidneys for the landscape. They can remove all kinds of dangerous chemicals and harmful pollutants found in our watercourses, from artificial fertilisers running off agricultural fields, to industrial wastewaters escaping from factories.
They achieve this by complex physical, biological and chemical processes. As they grow, wetland plants take-up some of the pollutants from the water, while microorganisms in the saturated soils store and break down others using special enzymes.
This combination can be so effective that wetlands are now being constructed to help purify specific types of wastewater – some of it destined for drinking water. These water-treatment wetland designs can be as simple as a reedbed to clean septic-tank runoff, and as complex as hybrid systems for treating pharmaceutical waste.
Crucially, unlike other water-treatment processes, wetlands create vital habitats for animals and birds, oasis of nature often in urban settings. Insects such as dragonflies and damselflies, birds like herons and grebes, freshwater fish and even otters have been known to visit them.
