reed:reed_beds

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reed:reed_beds [2025/12/05 11:10] – davereed:reed_beds [2025/12/17 11:25] (current) – external edit 127.0.0.1
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-Yellow flag, or _Iris pseudacorus_, is a common plant in constructed wetlands and reed beds. Source: [FH Wetland Systems](http://www.wetlandsystems.ie/)+_Yellow flag, or _Iris pseudacorus_, is a common plant in constructed wetlands and reed beds. Source: [FH Wetland Systems](http://www.wetlandsystems.ie/)_
  
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-The following physical, chemical and biological treatment mechanisms all come into play (see [glossary](/reed/reed_beds) for explanations):+The following physical, chemical and biological treatment mechanisms all come into play (see [glossary](https://www.lowimpact.org/categories/reed-beds/further-info/glossary) for explanations):
  
 - sedimentation - sedimentation
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-Soil-based constructed wetland section. Source: _Permaculture Guide to Reed Beds._+_Soil-based constructed wetland section. Source: _Permaculture Guide to Reed Beds.__
  
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-Horizontal flow gravel reed bed section. Source: _Permaculture Guide to Reed Beds._+_Horizontal flow gravel reed bed section. Source: _Permaculture Guide to Reed Beds.__
  
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-**Vertical flow (VF) reed beds**: similar in layout to a raised sand polishing filter or stone trickling filter. Vertical flow reed beds have a smaller footprint area than horizontal flow gravel reed beds, so may be more suited to small sites. The VF reed bed consists of c.1m depth of gravel, of progressively smaller particle sizes towards the bed surface. Effluent is dosed over the bed surface either by [pumped feed](/reed/reed_beds) or [gravity dosing mechanism](/reed/reed_beds) and treatment occurs as it trickles down over the gravel media and plant roots. Bear in mind that VF reed beds filled or topped with sand can be prone to blocking unless the exact aggregate grades are used and the correct degree of pretreatment is consistently achieved.+**Vertical flow (VF) reed beds**: similar in layout to a raised sand polishing filter or stone trickling filter. Vertical flow reed beds have a smaller footprint area than horizontal flow gravel reed beds, so may be more suited to small sites. The VF reed bed consists of c.1m depth of gravel, of progressively smaller particle sizes towards the bed surface. Effluent is dosed over the bed surface either by [pumped feed](https://www.lowimpact.org/categories/reed-beds/further-info/glossary) or [gravity dosing mechanism](https://www.lowimpact.org/categories/reed-beds/further-info/glossary) and treatment occurs as it trickles down over the gravel media and plant roots. Bear in mind that VF reed beds filled or topped with sand can be prone to blocking unless the exact aggregate grades are used and the correct degree of pretreatment is consistently achieved.
  
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-Vertical flow reed bed section. Source: _Permaculture Guide to Reed Beds._+_Vertical flow reed bed section. Source: _Permaculture Guide to Reed Beds.__
  
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-Newly planted domestic gravel reed bed system for septic tank effluent treatment prior to percolation. Source: [FH Wetland Systems](http://www.wetlandsystems.ie/)+_Newly planted domestic gravel reed bed system for septic tank effluent treatment prior to percolation. Source: [FH Wetland Systems](http://www.wetlandsystems.ie/)_
  
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-Great overview of constructed wetlands and why they are such sustainable systems.+_Great overview of constructed wetlands and why they are such sustainable systems._
  
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-Water lilies (Nymphaea alba cultivar) in a constructed wetland pond. Source: [FH Wetland Systems](http://www.wetlandsystems.ie/)+_Water lilies (Nymphaea alba cultivar) in a constructed wetland pond. Source: [FH Wetland Systems](http://www.wetlandsystems.ie/)_
  
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 - The gravel media has the potential for clogging if the septic tank isn't properly maintained. One potential solution is to install two septic tanks before the reed bed, or to use a septic tank filter unit at the outlet pipe. Nonetheless, maintenance is a bigger factor for reed beds than for soil-based wetlands. - The gravel media has the potential for clogging if the septic tank isn't properly maintained. One potential solution is to install two septic tanks before the reed bed, or to use a septic tank filter unit at the outlet pipe. Nonetheless, maintenance is a bigger factor for reed beds than for soil-based wetlands.
  
-- If you are using a small [modular unit](/reed/reed_beds) then it is extra important that your [mechanical treatment unit](/reed/reed_beds) is functioning at top efficiency all of the time to ensure that the overall system performs as designed. (Modular units are usually used only for tertiary treatment after a [mechanical aeration unit](/reed/reed_beds)).+- If you are using a small [modular unit](https://www.lowimpact.org/categories/reed-beds/further-info/glossary) then it is extra important that your [mechanical treatment unit](/reed/reed_beds) is functioning at top efficiency all of the time to ensure that the overall system performs as designed. (Modular units are usually used only for tertiary treatment after a [mechanical aeration unit](https://www.lowimpact.org/categories/reed-beds/further-info/glossary)).
  
 - At some stage, the gravel will clog up anyway. Bacteria mass, sediments and plant debris will all contribute to the eventual congestion of the gravel. While soil-based wetlands have an adjustable flow control unit that can simply be raised as sediment levels rise, gravel reed beds will need a complete overhaul every 15 to 30 years depending on influent quality, system size and throughput volumes. - At some stage, the gravel will clog up anyway. Bacteria mass, sediments and plant debris will all contribute to the eventual congestion of the gravel. While soil-based wetlands have an adjustable flow control unit that can simply be raised as sediment levels rise, gravel reed beds will need a complete overhaul every 15 to 30 years depending on influent quality, system size and throughput volumes.
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-Reed bed mid-construction: upper vertical flow bed followed by lower horizontal flow reed bed, then planted with Phragmites and Iris. Source: [FH Wetland Systems](http://www.wetlandsystems.ie/)+_Reed bed mid-construction: upper vertical flow bed followed by lower horizontal flow reed bed, then planted with Phragmites and Iris. Source: [FH Wetland Systems](http://www.wetlandsystems.ie/)_
  
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-**Vertical flow reed beds** are generally used to pretreat effluent entering a horizontal flow reed bed, where a higher quality of effluent is needed in a small space. They can also be effective where good soil percolation characteristics exist, but where a quick burst of treatment is needed prior to discharge to ground. Their main drawback is that a pump is usually needed to provide the required distribution of effluent over the reed bed surface. That said, a [gravity splitter, dosing box or syphon](/reed/reed_beds) may all be used where suitable falls are present.+**Vertical flow reed beds** are generally used to pretreat effluent entering a horizontal flow reed bed, where a higher quality of effluent is needed in a small space. They can also be effective where good soil percolation characteristics exist, but where a quick burst of treatment is needed prior to discharge to ground. Their main drawback is that a pump is usually needed to provide the required distribution of effluent over the reed bed surface. That said, a [gravity splitter, dosing box or syphon](https://www.lowimpact.org/categories/reed-beds/further-info/glossary) may all be used where suitable falls are present.
  
 Advantages: Advantages:
  
-- Vertical flow reed beds are good for stripping ammonia (the smelly component) from septic tank effluent. They’re also efficient for [BOD](/reed/reed_beds) and suspended solids reductions in tandem with horizontal flow reed beds.+- Vertical flow reed beds are good for stripping ammonia (the smelly component) from septic tank effluent. They’re also efficient for [BOD](https://www.lowimpact.org/categories/reed-beds/further-info/glossary) and suspended solids reductions in tandem with horizontal flow reed beds.
  
 - They can be very effective where space is limited, because they reduce the overall size needed for secondary treatment, which in turn reduces the required size of the follow-up tertiary treatment wetland and final infiltration area. - They can be very effective where space is limited, because they reduce the overall size needed for secondary treatment, which in turn reduces the required size of the follow-up tertiary treatment wetland and final infiltration area.
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-Common reed (Phragmites australis) is the most common species used in constructed wetlands and reed beds. The dense growth and vigorous roots provide excellent conditions for filtering water. Shown here beside a stormwater pond. Source: [FH Wetland Systems](http://www.wetlandsystems.ie/)+_Common reed (Phragmites australis) is the most common species used in constructed wetlands and reed beds. The dense growth and vigorous roots provide excellent conditions for filtering water. Shown here beside a stormwater pond. Source: [FH Wetland Systems](http://www.wetlandsystems.ie/)_
  
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 Limitations: Limitations:
  
-- A pumped feed is usually needed, which can add to ongoing energy needs and costs. However, where there is a fall on the site a [gravity dosing box, siphon system or effective splitter unit](/reed/reed_beds) may be used instead.+- A pumped feed is usually needed, which can add to ongoing energy needs and costs. However, where there is a fall on the site a [gravity dosing box, siphon system or effective splitter unit](https://www.lowimpact.org/categories/reed-beds/further-info/glossary) may be used instead.
  
 - VF reed beds are best used in conjunction with a horizontal flow bed or other treatment component, and the requirement for an extra system can add to the cost of a project. - VF reed beds are best used in conjunction with a horizontal flow bed or other treatment component, and the requirement for an extra system can add to the cost of a project.
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 There are a number of stages to any reed bed project. The more you can do yourself, the lower the overall cost. Reed beds and constructed wetlands generally require planning permission, so if you are good at preparing site drawings, system drawings and good at sourcing design information, this is something you can do yourself. Otherwise you may wish to hand over to a consultancy that specialises in constructed wetland and reed bed design. The excavation, lining, pipework and manhole construction all require input by somebody skilled in that kind of thing. You may hire a mini digger and do it yourself, or you may wish to hire a groundworks contractor, landscaper or sewage treatment system specialist. Planting with the right plants is the final stage (to be carried out before connecting the septic tank!). If you have a boggy field nearby with the right plants, that will be the lowest carbon footprint approach. You may also buy from specialist suppliers if you are stuck. Planting isn't rocket science, but be sure to put the green bit up and the rooty bit down (it happens...). The _Permaculture Guide to Reed Beds_ gives guidance on all of these stages, so if you want to do it yourself, it may be a good book to start with. There are a number of stages to any reed bed project. The more you can do yourself, the lower the overall cost. Reed beds and constructed wetlands generally require planning permission, so if you are good at preparing site drawings, system drawings and good at sourcing design information, this is something you can do yourself. Otherwise you may wish to hand over to a consultancy that specialises in constructed wetland and reed bed design. The excavation, lining, pipework and manhole construction all require input by somebody skilled in that kind of thing. You may hire a mini digger and do it yourself, or you may wish to hire a groundworks contractor, landscaper or sewage treatment system specialist. Planting with the right plants is the final stage (to be carried out before connecting the septic tank!). If you have a boggy field nearby with the right plants, that will be the lowest carbon footprint approach. You may also buy from specialist suppliers if you are stuck. Planting isn't rocket science, but be sure to put the green bit up and the rooty bit down (it happens...). The _Permaculture Guide to Reed Beds_ gives guidance on all of these stages, so if you want to do it yourself, it may be a good book to start with.
  
-See our [further information](/reed/reed_beds) section for summary guides to constructing different types of reed beds, and [here’s](http://lowimpactorg.onyx-sites.io/installing-horizontal-flow-reedbed/) a pictoral guide to installing a horizontal flow reed bed.+See our [further information](https://www.lowimpact.org/categories/reed-beds/further-info) section for summary guides to constructing different types of reed beds, and [here’s](http://lowimpactorg.onyx-sites.io/installing-horizontal-flow-reedbed/) a pictoral guide to installing a horizontal flow reed bed.
  
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-Excellent demonstration of constructed wetlands for wastewater treatment in Catalunia.+_Excellent demonstration of constructed wetlands for wastewater treatment in Catalunia._
  
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 Below is a rough guide, based on sizing recommendations from the [EPA](http://www.epa.ie/pubs/advice/water/wastewater/code%20of%20practice%20for%20single%20houses/#.U00LISgww7s) (Ireland) and [GBG-42](https://www.thenbs.com/PublicationIndex/documents/details?Pub=BRE&DocID=250722) (UK). Below is a rough guide, based on sizing recommendations from the [EPA](http://www.epa.ie/pubs/advice/water/wastewater/code%20of%20practice%20for%20single%20houses/#.U00LISgww7s) (Ireland) and [GBG-42](https://www.thenbs.com/PublicationIndex/documents/details?Pub=BRE&DocID=250722) (UK).
  
-| **System type** | **Size per [p.e.](/reed/reed_beds)** | **Minimum size** |+| **System type** | **Size per [p.e.](https://www.lowimpact.org/categories/reed-beds/further-info/glossary)** | **Minimum size** |
 | Horizontal flow gravel reed bed | 5m² | 25m² | | Horizontal flow gravel reed bed | 5m² | 25m² |
 | Vertical flow gravel reed bed | 1-3m² | 15m² | | Vertical flow gravel reed bed | 1-3m² | 15m² |
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 ![](https://www.lowimpact.org/wp-content/uploads/reed-beds-newly-planted-soil-based.jpeg) ![](https://www.lowimpact.org/wp-content/uploads/reed-beds-newly-planted-soil-based.jpeg)
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-Newly planted soil-based constructed wetland system. Source: [FH Wetland Systems](https://wetlandsystems.ie/)+_Newly planted soil-based constructed wetland system. Source: [FH Wetland Systems](https://wetlandsystems.ie/)_
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 ![](https://www.lowimpact.org/wp-content/uploads/reed-beds-ducks.png) ![](https://www.lowimpact.org/wp-content/uploads/reed-beds-ducks.png)
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-Ducks on a new SUDS wetland pond in Co. Limerick, Ireland. Source: [FH Wetland Systems](https://wetlandsystems.ie/)+_Ducks on a new SUDS wetland pond in Co. Limerick, Ireland. Source: [FH Wetland Systems](https://wetlandsystems.ie/)_
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 ## Further resources ## Further resources
  
-## Specialists+## Specialist curators of this topic
  
  
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  • by dave