What is it used for?
Filter marshes provide an effective and environmentally friendly alternative to septic tanks, leaching fields and sewer systems:
- As self-sufficient systems, they require little maintenance.
- Their installation and operation cost less than traditional methods.
- They do not require any chemicals and little or no energy from external sources.
- They provide a habitat for wildlife and beautify the landscape.
The vast majority of artificial filter marshes treat domestic wastewater, but they can also purify effluent from fish farming, paper mills, dairy farms, landfills and mining operations.
How is it made?
A typical filter marsh consists of a basin with or without a substrate (soil or gravel), a wastewater intake system and a purified water output system. Plants (floating or rooted) play an essential role. Their roots, and particularly the microorganisms associated with them, promote the breakdown of numerous pollutants.
There are several types of filter marshes, which are suited to specific uses and regions. Hybrid filter marshes combine many of their best features, allowing users to benefit from the many purification mechanisms.
Until recently, the common reed (phragmites australis) was the star plant in filter marshes, but it is no longer allowed in Quebec because of its invasive nature. Fortunately, researchers have identified other extremely effective plants, including cattails