Constructed wetlands are marshes built to treat contaminated water.
They have four key components:
- Soil and drainage material (such as pipes and gravel)
- Water
- Plants (both above and below the water)
- Micro-organisms
Constructed wetlands purify the water that flows through them. Compared to conventional treatment methods, they tend to be simple, inexpensive, and environmentally friendly.
Constructed wetlands may be used to treat water from many different sources:
- Sewage (from small communities, individual homes, and businesses)
- Stormwater
- Agricultural wastewater (including livestock waste, runoff, and drainage water)
- Landfill leachate
- Partially treated industrial wastewater
- Drainage water from mines
- Runoff from highways
Constructed wetlands also provide food and habitat for wildlife and create pleasant landscapes.
Constructed wetlands differ from natural wetlands in several ways:
- They remain constant in size
- They are not directly connected with groundwater
- They accommodate greater volumes of sediment
- They more quickly develop the desired diversity of plants and associated organisms.
