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This section answers the most frequently asked questions regarding RBTS.
Marshlands are Nature's kidneys, just as forests are her lungs. They clean water using processes as old as Life itself :
What is a Reed Bed System ? An excavated or constructed container, filled with gravel and sand or soil. It is planted with a variety of aquatic plants, with an emphasis on species such as the Common Reed (Phragmites Australis) and Reedmace (Typha Latifolia). There are two main types of gravel-based reed bed (such as those designed by Natural Technology Systems) :
Vertical Flow Reed Beds (VFRB's) : These can handle large quantities of sewage, and are most effective at reducing BOD by oxygenation, and Suspended Solids. The liquid flows onto the surface and percolates downwards and quickly away, before the airspaces between the gravel fill up with air again.
Horizontal Flow Reed Beds (HFRB's) : These are continuously full of water (to just below the gravel surface), encouraging zones of anaerobic activity which are effective at stabilising ammonia and nitrates.
How Do They Work ? The reed bed is preceded by a settlement/septic tank, which settles out and liquifies the sewage. A two-chamber tank, conforming to local Building Codes, is recommended. As the wastewater enters the reed bed, organic material and fine particles are filtered by the gravel, and form a slime on the gravel. Large populations of bacteria and other organisms convert the slime into harmless forms, such as water, carbon dioxide, nitrogen. They also convert nitrates in the wastewater into forms which are more easily taken up by plants. Harmful pathogens, such as E.Coli and Salmonella, are killed off by other bacteria which are much more suited to the reed bed environment.
Does the Reed Bed need the plants ? Yes. The plants, which are all native, provide ideal conditions around their roots for the sewage-eating bacteria to operate. Some of the plants pass oxygen down from their leaves to this root zone. The aggressive root systems of the plants, in what is, for them, ideal growing conditions, continually force the gravel apart, maintaining a hydraulic pathway which would soon be blocked up without the plants.
How big is a Reed Bed System ? : Using a combination of vertical and horizontal beds, full treatment can be achieved in around 3 m2 per person. The systems are designed to blend into the general landscape of their surroundings, and, once established, become a landscape feature and wildlife habitat in their own right.
What services do NTS provide ? : We can either design a RBTS for 'Self-Build' construction by our clients (or their own contractor), or we can contract to carry out the complete installation. With our design and construction information, the actual construction of a RBTS is not difficult. For self-build projects, we can also supply liners, plants, geo-textiles etc. (if they're not available locally), and will 'oversee' the project at critical stages of construction.
We can provide design and supervision on-line to anyone with a little common sense (and a tape measure). Our consultancy rates are reasonable. Please e-mail for details.
Are Reed Beds acceptable to Planning Authorities ? Yes. We provide all necessary documentation and design drawings to accompany a planning application. RBTS's have now been installed throughout Europe and USA, and although local codes may differ, wastewater is much the same everywhere.
In what circumstances is a Reed Bed System appropriate ? On all sites which fail the standard tests for groundwater and/or percolation, or are unsuitable for a conventional septic tank because of proximity to boundaries, wells etc.; In areas which have a problem with contamination of groundwater or eutrophication of watercourses; In developments where mains sewage treatment, or alternative package treatment plants would be too expensive; In commercial/industrial/agricultural situations.
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