What is a Reed Bed?

Oceans-ESU’s reed beds are highly engineered water treatment systems which are planted with Phragmites australis. These reeds have an extensive root system which provides an ideal habitat for natural soil bacteria to thrive. These bacteria are very efficient at degrading a wide range of common chemical pollutants. Oceans-ESU reed beds are designed and engineered to maximise the treatment efficiency depending on the effluent.

What is the difference between a reed bed and a constructed wetland?

Reed Beds are sometimes known as Constructed Wetlands or Engineered Wetlands. ‘Constructed wetland’ is a term sometimes used interchangeably with ‘reed bed’ but more often it is used to describe a gravel based reed bed or open water reed systems.

Oceans-ESU specialise in sub-surface flow, soil based reed beds, which have a much greater treatment capability than their gravel counterparts.

Why do Oceans-ESU use soil instead of gravel as the reed bed growing medium?

In a reed bed, the removal of contamination is carried out by bacteria living around the roots of the reeds. Soil not only provides a better medium for the developing roots, but it also brings a vast diversity in natural soil bacteria. As the reed bed is fed with dirty water, those bacteria with the capability of digesting the specific contaminants involved will have a constant food source, allowing them to multiply rapidly. Quickly the reed bed can become adapted for the efficient degradation of the specific chemicals present in the water. Soil also has a greater surface area than gravel, meaning increased bacterial habitat leading to a more efficient treatment system.

Finally, gravel reed beds often suffer from becoming blocked over the years, as solid particles fill the voids between the gravel. With soil systems, the water flow rates actually improve as the reed bed ages, as the developing root structure keeps the soil open facilitating the passage of water. Gravel systems often need periodic refurbishment to replace or wash the gravel, whereas soil systems can keep performing indefinitely with a bit of basic horticultural care.

What is Enhanced Reed Bed Treatment Technology?

ERT Technology® is a methodology developed by Oceans-ESU to enhance the capability of soil reed beds to treat more complex chemicals. A series of techniques are used to boost the ability of the reed bed to treat some of the more persistent chemicals, and to minimise the length of time for a new reed bed to reach full treatment capability.

What can Reed Beds treat?

Reed beds are very efficient at treating a wide range of chemical pollutants and waste waters. Examples include hydrocarbons, pesticides, domestic sewage, produced water, composting leachates, fire waters, chemical industry effluents, landfill leachates and many more.

Most organic chemicals can be degraded using soil based reed beds, even some of the more persistent and complex pollutants such as pesticides, chlorinated compounds, PAHs, PFOS and many more.

Reed beds can also be used to tackle inorganic pollutants such as phosphates and metals. While these cannot be degraded by bacteria, they can be removed from the water by entrapping them within a specially designed part of the reed bed system, known as a sacrificial bed. The sacrificial bed is filled with a carefully selected blend of soil and other material, designed to provide the necessary conditions to entrap the contaminant of concern. This material would need to be dug out periodically and replaced (typical designs would be for replacement after 5-10 years depending on project specifics).

What are the advantages and disadvantages of reed beds?

Reed beds provide environmentally friendly solutions for contaminated waste water problems. As well as providing a valuable wetland habitat for wildlife, they can also be an aesthetically pleasing feature to your development. Furthermore, reed beds are cost effective solutions with very low maintenance requirements (they regenerate naturally!).

The versatility of reed beds means that they are also adaptable. They can adjust to changes in effluent characteristics and they are generally robust enough to deal with short term fluctuations including peak loadings. This means they can form part of your emergency backup procedures (e.g. handling leaks/spills/fire waters) and they can even be recommissioned for a different purpose.

There are few disadvantages associated with reed beds as they are cost effective and they can meet or exceed the treatment capabilities of many mechanical alternatives. Reed bed size depends on the volume and chemical composition of the effluent, and so for certain applications a significant amount of land may be required.

Are there any health hazard or smells associated with reed beds and do they smell?

Contaminated water can present a health hazard and can smell, however Oceans-ESU reed beds are designed on the principle that all untreated water remains below the surface of the soil and is not exposed to the environment. It is important that reed beds are constructed and operated correctly to ensure that water remains below ground until it is treated, thus preventing the release of any odours. Maintenance personnel should follow a few simple procedures to maintain their safety while working in the system.

How do reed beds compare to other technologies?

Many waste water treatment systems available use four main techniques: Aerobic digestion, anaerobic digestion, ion exchange and filtration. When tailored to a specific source of contamination, the design of reed bed system can combine all four of these treatment techniques to produce the optimum treatment method. Soil based reed bed systems encourage bio-reactions to balance the aerobic and anaerobic digestion requirement with chemical absorption and adsorption in a filtering medium.

Reed bed systems are an effective and sustainable method of providing low maintenance solutions to waste water treatment. Once established the reed bed treatment system will require no electricity or chemicals and minimal operation cost. The initial construction costs are equivalent to other treatment systems, provided suitable land area is available.

We recognise that reed beds may not be the best solution for all situations. However, if you contact us with details of your treatment requirements, we can advise on the potential options of using reed beds for your waste water, allowing you to compare against other technologies.

What services do Oceans-ESU provide?

Oceans-ESU provide a range of services related to the design of reed bed systems. Requirements depend on the project, but some examples are as follows:

  • Reed bed design
  • Pre-design surveys to gather data required for reed bed design, which may include topographical surveys, water sampling, soil sampling, etc
  • Reed bed feasibility studies where required, which may include laboratory or field based trials to ascertain the treatability of more complex or unusual effluents
  • Construction Consultancy, to assist the client with contractor selection and management of the construction process
  • Reed supply and planting
  • Reed bed assessments and consultancy, to advise on any reed bed related issues
  • Training related to reed beds, their construction and their operation.

How big will my reed bed be?

Basic reed bed sizing is based upon the volume of water and the level of treatment required. We need to know how much water is to be treated, what type of water it is, and what you propose to do with the cleaned water. If you can provide any chemical analysis, that is always helpful, but in many cases we can make an initial rough prediction based on our experience of similar projects. Where possible, we will aim to quickly give you a rough indication of reed bed size and estimated costs for the project so you can decide whether a reed bed is right for you. If you decide to proceed, we would generally require more detailed information once we reach the design stage. If the required data isn’t available, we can either carry out the required surveys or support you with gathering the information yourself.

How much does a reed bed cost?

Reed bed cost depends on the size and design of the system, and should be agreed with the chosen contractor. At Oceans-ESU, we endeavour to design a solution to fit the customer’s needs and budget. Where possible, we design for simple, low cost construction, taking account of resources and materials that the customer may have available.

Once built, reed beds have low operational cost as they only need basic horticultural care. In many cases, water flow is by gravity so there are no electrical or mechanical parts, and soil reed beds do not need periodic replacement of the growing media.

Do I need planning permissions or an environmental permit to build a reed bed?

This depends on your location, but many countries will require you to seek permission before discharging the treated water to the environment.  Sometimes exemptions will apply (e.g. for certain agricultural activities or for small scale dicharges).

In England, planning planning permission and an environmental permit may be required.  Small scale sewage discharges may not require a permit if you comply with the Environment Agency general binding rules, but unfortunately reed beds are not currently recognised as a standard treatment system for domestic sewage (meaning a permit is likely to be required).  Permitting is administered by the national environment agency, so rules may differ in Wales, Scotland and Northern Ireland.

It is recommended that you contact your local authority (planning office) and relevant environmental agency to discuss your plans and to get guidance on what is required. We can provide assistance with planning and permitting applications if required.

Who will build the reed bed?

Once Oceans-ESU has completed the reed bed design, you are free to choose your own preferred contractor to carry out the installation, or you can build it yourself if you prefer. We can provide Construction Consultancy services to assist you with managing the process and helping with any questions the contractor may have.
Oceans-ESU can supply and plant the reeds (Phragmites australis) if required.

How long does it take to build a reed bed?

Construction time varies depending on the size and complexity of the reed bed and local site conditions and larger systems can take several weeks. Construction schedules would need to be agreed with the contractor installing your system.

Will the reed bed need ongoing maintenance?

Our soil based reed beds are designed to be low maintenance, but they do need a little care and attention, especially in the first couple of years as the reeds establish. Maintenance typically consists of checking the health and growth of the reeds and ensuring that weeds do not overwhelm the system before the reeds can establish. Pipes should be rodded out periodically to prevent blockages, and water levels should be checked occasionally.

We offer a range of maintenance programmes to meet our customers’ requirements and budgets, and we can provide training to allow reed bed owners or site staff to carry out their own maintenance.

I think I have a reed bed that isn’t working, can you help?

Please feel free to call us to discuss the problem. Many issues with reed beds can be easily resolved, and we are happy to offer advice on any reed bed problems.

If you have further questions you would like answered please email: contact@oceans-esu.com


  • Reed beds provide a green feature and benefit wildlife in a world where natural wetlands are becoming scarce

  • Soil based reed beds are cheap to operate and maintain

  • ERT Technology® cleans polluted waters by harnessing the natural power of nature

  • ERT Technology® offers enhanced treatment capabilities compared to standard constructed wetlands

  • Bacteria found in soil based reed beds are capable of breaking down many persistent organic pollutants

      • 6
      • 2012
        football pitches worth of reedbeds built
      • 13
        million reeds planted
      • 35yrs
      • 358
        million litres of water treated daily (that’s 143 Olympic swimming pools!)

Accreditations / Certificates