Reedbeds for Nutrient Neutrality

The environmental issue of nutrient pollution

Nutrient pollution poses a significant environmental threat to critical natural areas in England, significantly impacting freshwater habitats and estuaries.

The population and new housing developments increase concerns about elevated nutrient levels in lakes and waterways. This surge in sewage treatment needs is pressuring Water Companies to expand capacity, often to unsustainable levels.

Discharging phosphates and nitrogen-rich effluents from sewage works into rivers and streams ultimately affects the marine environment. High nutrient loadings typically lead to eutrophication, causing oxygen depletion, habitat deterioration, and declining wildlife.

Natural England's guidance mandates 'nutrient neutrality' for new residential developments, significantly impeding planning permissions in areas grappling with nutrient-related challenges.

Reedbeds as a Viable Solution

  • By tackling nutrient pollution at the source, pressures can be reduced on protected sites upfront, and burdens on mitigation for new housing developments can be reduced. The Government advocates for, wherever feasible, the integration of nature-based solutions in these upgrades, such as incorporating wetlands and reedbeds alongside traditional methods to enhance nutrient removal from the wastewater and act as natural water treatment systems.

  • 4R Reedbeds presents a solution by incorporating reed-bed systems that reduce total nutrient levels in final discharges. Ammoniacal nitrogen reduction is quickly and efficiently achieved as aerobic conditions facilitate the breakdown of Ammonia into nitrites and nitrates.

  • A 0.5 Hectares Constructed Wetland would offset nutrients from approximately 24 new homes.

  • Studies have demonstrated that planting reeds (Phragmites australis) through which water can flow highly effectively removes phosphate (95%) and excellently removes nitrate (85%). Additional benefits could include biodiversity enrichment and carbon sequestration.

What is Nutrient Neutrality?

  • Excessive nutrient levels in water courses typically lead to eutrophication, causing oxygen depletion, habitat deterioration, and a decline in aquatic life. Typical sources of nutrients which leach to watercourses are sewage treatment works (STW), agricultural activities, septic tanks and package plants and diffuse urban sources with STWs providing the biggest contribution (60-70%).

  • According to Natural England’s 2023 publication, ‘Net Neutrality and Nutrient Mitigation’, net nutrient neutrality is described as a concept that aims to ensure that a development plan or project does not add to existing nutrient burdens within catchments, so that there is no net increase in nutrients as the result of a plan or project.

  • In order address this issue, Natural England's guidance mandates nutrient neutrality for new residential developments, significantly impeding planning permissions in areas already grappling with nutrient-related challenges.

  • Criteria which potential mitigation techniques must meet in order to be both compliant and more likely to have a successful result. These are, that the mitigation practice must be within the same catchment and benefiting the impacted habitats site, positioned upstream or at the point of impact, scientifically sound, lasting and in operation prior to the planned developments occupation, and therefore impact.

  • Natural England acknowledges a gap in the available information regarding mitigation measures. Due to the distinctiveness of each catchment, there is currently no universal tool for mitigation. Natural England is actively working on providing additional information about various mitigation interventions and guidance on their optimal applications, with plans to release this information to Local Planning Authorities (LPAs) in the Summer.

  • At present, the responsibility for achieving nutrient neutrality lies with developers. Developers must calculate a nutrient budget for proposed projects and implement mitigation if necessary to keep loadings within acceptable limits.

Reedbeds and wetlands for nutrient neutrality

  • By tackling nutrient pollution at the source, pressures on protected sites can be reduced upfront, and mitigation burdens on new housing developments can be reduced. The Government advocates for, wherever feasible, the integration of nature-based solutions in these upgrades, such as incorporating wetlands and reedbeds alongside traditional methods, like the addition of metal salts to wastewater, to enhance nutrient removal from the wastewater.

  • 4R Reedbeds presents a solution by incorporating reed-bed systems that combine vertical and horizontal flow reed beds with wetlands, ponds, and recirculation via artificial streams and waterfalls to effectively reduce total nitrogen levels in final discharges. Ammoniacal nitrogen reduction is easily and efficiently achieved in our vertical flow reed beds, where aerobic conditions facilitate the breakdown of Ammonia into nitrites and nitrates.

  • A 0.5-hectare Constructed Wetland would "offset" nutrients from approximately 24 new homes.

  • Studies have demonstrated that a constructed wetland featuring the planting of reeds (Phragmites australis) through which water can flow exhibits highly effective phosphate removal (95%) and excellent nitrate removal (85%).

  • In horizontal flow beds, nitrites and nitrates are converted into nitrogen gas under anoxic conditions, escaping into the air. This process is further optimised in ponds and wetlands where water recirculation maintains low oxygen levels, preventing stagnation. These systems can be creatively landscaped to form aquatic features or as recreational focal points within housing or commercial developments.

  • Contact 4R Reedbeds to help you through this process from a Nutrient Neutrality Report, a Phosphate Assessment, Phosphate Budget Calculators, Phosphate Credits, Nutrient Neutrality Assessment and  Mitigation Strategy (NNAMS), and you are looking for practical help to construct and maintain a reedbed or wetland.

Nutrient Neutrality Mitigation

  • Natural England acknowledges a gap in the available information regarding mitigation measures.

  • Due to the distinctiveness of each catchment, there is currently no universal tool for mitigation, and the approach needs to be customised.

  • Natural England is actively working on providing additional information about various mitigation interventions and guidance on their optimal applications, with plans to release this information to Local Planning Authorities (LPAs) in the Summer.

  • Applicants for diverse developments, such as agriculture and industry, will be required to furnish customised nutrient calculations, recognising the site-specific nature of these proposals.

What is the Nutrient Mitigation Scheme?

  • Natural England is launching a program to provide additional mitigation measures in conjunction with current and upcoming efforts. The Department for Environment, Food & Rural Affairs (Defra) and the Department of Levelling Up, Housing, and Communities (DLUHC) are collaboratively investing up to £30 million in this initiative over the next three years.

Nutrient Neutrality Credits

  • Credits will be available in batches, and any developer can apply. In cases where the demand for credits surpasses the supply, applications will be prioritised. Credit availability and pricing information will be disclosed before the commencement of the first credit sales.

  • By securing credits through nutrient certificates issued by Natural England, developers offer assurance to Local Planning Authorities (LPAs) that they can meet the nutrient neutrality planning conditions.