Constructed wetlands for improving water quality
Wetlands constructed for the primary purpose of treatment to improve water quality will need an Environmental Permit. This is to ensure the wetland treats the flow passing through it to the required standard to protect the environment.
The type of Environmental Permit you need will depend on your circumstances.
You may need an Environmental Permit for water discharge, or an Environmental Permit for waste that will include the water discharge activity.
Constructed wetlands for treatment to achieve nutrient neutrality will also be assessed in line with our nutrient neutrality principles.
Any application for a permit will be determined on a case-by-case basis in accordance with NRW’s procedures and statutory framework.
Constructed wetlands built to improve water quality will usually comprise of one or more cells containing emergent vegetation appropriate for the required treatment. They will be designed and maintained to receive and treat waters / effluents / wastewaters so that any discharge from the constructed wetland will not pollute the surface or ground water.
Constructed wetlands for water quality improvement must not be located in:
- Flood Zone 3 (areas at risk of frequent flooding)
- in a water supply Source Protection Zone (SPZs) if the treated effluent is subsequently discharged to ground
- a site designated for nature conservation or geological importance unless there is no adverse impact on designated features or it can be shown to have a significant net benefit for the features of the site as part of the conservation management needs.
Impact on a designated site will require an assessment, such as the Habitats Regulations Assessment (HRA) or SSSI consenting process.
Constructed wetlands for treated sewage effluent
If your constructed wetland is part of the treatment system, (prior to the permit monitoring point), you will need to apply for a Water Discharge Permit or a Groundwater Activity Permit.
If your constructed wetland is situated after the treatment works permit monitoring point, you should request our pre-application advice service as we will need to understand more about your proposal.
Constructed wetlands for untreated sewage effluent
If your constructed wetland is receiving untreated sewage effluent from a public sewer permitted overflow or as part of the agreed treatment system, you will need to apply for a Water Discharge Permit or a Groundwater Activity Permit.
Constructed wetlands for contaminated water from mines or mineral activities
If your constructed wetland is receiving water from mines or mineral activities, you will need to apply for a Water Discharge Permit or a Groundwater Activity Permit.
Constructed wetlands for treated waste effluent from a waste operation
If your constructed wetland is receiving treated water from a waste operation, you will need to apply for a Waste Environmental Permit. This includes tertiary treatment of treated agricultural effluents. The constructed wetland would be part of the waste activity, regulated under a single waste permit.
Constructed wetlands for agricultural activities
Effluents, liquors and washings regulated under current legislation cannot be treated in a constructed wetland. They must be collected, stored and disposed of in a legally compliant way. Effluents, liquors and washings includes but is not limited to:
- silage effluent and slurry,
- poultry unit verandas, collecting yards, feeding areas and parlour washings
- pesticides, biocides, including areas, equipment and washings that have been in contact with these products.
If your constructed wetland is to treat rainwater runoff from buildings housing livestock with roof vents and / or tracks used by livestock, you will need to apply for a permit.
Other types of water to be treated by the constructed wetland
If your constructed wetland is receiving water from a source not mentioned above, you should apply for our pre-application advice service, as we will need to understand more about your proposal.