• Reed Beds Sewage Treatment

    WCI have been designing and constructing reedbeds for over 20 years.

A reed bed, or constructed wetland, is a natural form of domestic wastewater treatment. Reed bed systems are an effective, sustainable and aesthetic method of sewage treatment.

Benefits at a glance

No electricity required

Completely silent

Environmentally-friendly

Aesthetically sympathetic

Low running and lifetime cost

Provides additional habitat for wildlife

Types of Reed bed

Types of reedbeds

There are two main types of reed bed. Horizontal and vertical flow.

Horizontal flow (HF) reed beds are shallow lined structures which are constantly flooded to just below the gravel line. The effluent enters at one end and travels horizontally through the reeds bacteria rich root zone, before being discharged on the far side of the bed. The Common Reed Phragmites Australis is able to transfer oxygen from its leaves, down through its stem and rhizomes into the gravels around the root system creating a high population of micro organisms.

Vertical flow (VF) reed beds are lined, deeper structures made up of layers of various sized gravels planted with reeds. It is a free draining structure where effluent is delivered to the top of the bed in batches (by gravity dosing unit or electrical pump), floods the surface of the bed and drains through. Each batch traps oxygen in the bed leading to an aerated system. VF systems are more effective than HF systems at ammonia removal due to increased oxygen levels within them. VF systems have a smaller footprint than HF systems and can cope with stronger effluents.

VF and HF beds can be installed together in a Hybrid system to achieve a higher standard of discharge or where influent strength is higher.

Maintenance requirements

Reed beds do require maintenance, but not as much as you might think. In the first year or two (until the reeds are fully established) it will be necessary to weed the reed bed. This ensures that the reeds are the dominant species in the bed and the coverage is in excess of 70%, as specified by Environment Agency permitting. Once established, it is good practice to cut the reeds back to their bases at the end of each growing season to encourage new growth from the rhizomes. No other maintenance should be required.

Please note: when maintaining reed beds, protective clothing, gloves and eye wear should be worn. We currently have 17- year-old reed beds achieving EA permit criteria without the need for replacing the gravels. This has been achieved with regular simple maintenance of the bed and annual emptying of the preceding septic tank (as would be needed if the system was a soakaway system).

Why choose a reed bed?

Reed beds provide aesthetically pleasing, eco-friendly non-electrical alternatives to electrical sewage treatment plants. Historically, the reed bed was the only form on non-electrical sewage treatment available. However, with the advent of non-electrical package sewage treatment plants, reed beds are less frequently used for ‘secondary’ treatment (meaning the main form of biological treatment).

Reed beds are still frequently employed for tertiary treatment or for polishing sewage treatment plant effluent in order to reach stringent effluent quality requirements. Reed beds are also frequently employed to reduce flow rates to sensitive watercourses in the summer months from seasonal applications such as caravan parks. Finally, reed beds can also be adopted to provide a natural, aesthetically pleasing face to otherwise industrial-looking sewage treatment plants in applications where brand, desire or belief requires it.

Case Studies

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