Reed Beds

Constructed wetlands

Reed beds are either naturally occurring around the edge of still waters, or are artificially constructed.

Artificial reed beds or 'constructed wetlands', are an installation of aquatic plants that are used to treat wastewater.

How does a reed bed system differ from a treatment plant?

A reed bed is a natural system, employing zero chemical treatments and requiring minimal maintenance — a contrast to treatment plants that are extremely expensive to build, consume many acres of land and require careful chemical control.

Whilst not an end-to-end solution like a treatment plant is, specially constructed reed bed systems have the ability to filter and process nutrient-rich wastewater by biological action. This is known as ‘polishing’ the effluence.

Reed bed systems (specifically of ‘horizontal flow') are designed to serve as a ‘secondary’ or ’tertiary’ treatment for strong industrial effluent, stormwater and greywater (from showers, baths and basins). This makes a reed bed system an excellent option for rural businesses who produce industrial effluence which can be returned directly to a watercourse, rather than putting a strain on local wastewater treatment plants. This is great for a business’ environmental policy and green credentials.

Despite reed bed systems being tested in Bangladesh as a technique for treating faecal wastewater as recently as August 2020, most countries around the world rely on sewage treatment plants to treat blackwater (wastewater from toilets). Therefore, a reed bed system is not an outright replacement for a treatment plant, but rather an environmentally-friendly solution to the latter stages of the process.

How does a reed bed system work?

Wetland plants, usually Common reed (Phragmites australis), introduce atmospheric oxygen into the substrate creating aerobic, anoxic and anaerobic zones where the microorganisms break down contaminants.

Have a question about reed beds and constructed wetlands? We’d love to help.