Our work in Special Areas of Conservation water bodies

The Technically Achievable Limit is the absolute maximum phosphorous that a water company is able to remove at each wastewater treatment works.

This is currently set at a concentration of 0.25mg/l of Total Phosphorus in a Waste Water Treatment Works discharge. The costs of achieving this limit with any certainty are extremely high and significant capital works would be required to meet this limit. This would need to be planned in for the next investment cycle.

DEFRA recently indicated that all Waste Water Treatment Works in England (over a certain population threshold) discharging to a Special Area of Conservation, that is not in favourable status would need to have a Technically Achievable Limit applied. This would likely be planned in Price Review 24 with the works to implement this occurring between 2025 and 2030.

It has been agreed with the regulator that we will not need to apply Technically Achievable Limit as a default to works discharging to failing Special Areas of Conservation in those parts of England that we serve.

In Wales and the areas of England that we serve, it has been agreed with the Environmental Regulators that measures taken should be proportionate to the cause of failure following the ‘polluter pay’ principle. This means we will continue with the joint water quality modelling and invest in phosphorus removal at Waste Water Treatment Works where required to address our ‘fair share’.

In the Wye catchment we know that the application of Technically Achievable Limit would not solve the phosphorus problem as other sectors would also need to remove significant amounts of phosphorus. We can also assume that until the river is in favourable status, nutrient neutrality will still need to be considered.

Should Technically Achievable Limit be required, this would go some way to addressing excess phosphorus within the river. However, it would not be sufficient to bring about ‘favourable condition’ / good status of the Special Area of Conservation. Measures to prevent deterioration of the area would also be needed to make progress towards good status. We do not expect any credits to be created from the application of Technically Achievable Limit.

The environmental regulators will require a 5mg/l Total Phosphorus permit limit to be applied to wastewater treatment works over a certain population threshold, discharging to a Special Area of Conservation. This will be actioned in Asset Management Period 8 (2025-2030). The new permit limits give greater certainty to prevent deterioration and the statutory requirement to sample and report Waste Water Treatment Works’ final effluent for phosphorus. The backstop limit will also give greater certainty to water quality modelling where the new limit will replace estimated total phosphorus values in previous versions.

We are aware of a number of developers that are investigating the use of private treatment options. In line with Natural Resources Wales’ latest Planning Advice (published 26th July 2022), whilst we can offer advice to developers and Local Planning Authorities on proposals that seek to utilise private chemical pre-treatment that discharges into the public sewer, ultimately the matter is one for the Local Planning Authority to determine as the competent authority.

We do however retain some concerns about this type of proposal that we would seek further clarification on:

• Potential for detrimental impact and injurious harm to the public sewer and receiving Wastewater Treatment Works
• Guarantee on the long-term management and maintenance of such private treatment plants
• Environmental impact of chemical dosing via intermittent discharges

Whilst we want to play our part in enabling development, we would require assurances from the developer in liaison with the LPA and NRW that the above concerns are met.

The requirement for a Waste Water Treatment Works to include phosphorous within its environmental permit is determined by Natural Resources Wales / Environment Agency via the National Environment Programme (NEP), with schemes subsequently included within our AMP process.

At this time there is no mechanism to deliver phosphorus removal at our Waste Water Treatment Works outside of the AMP process, but following the First Minister’s Phosphorous Summit at the Royal Welsh Show, we are in discussions with the Welsh Government; Natural Resources Wales; House Builder’s Federation, and other stakeholders to determine whether it is possible (from a regulatory perspective) to enable developer funded phosphorus removal.

Nutrient Management Boards

Nutrient Management Boards (NMB) will play an increasingly important role over the coming years and are already proving successful on the Wye in Herefordshire where the water and development sector, including Local Planning Authorities are working together to build eight wetland areas to reduce nutrient loading on the Lugg (tributary of the Wye.

The approach in Hereford aims to ‘unlock’ development through the Local Authority planning process – with a Phosphate Credit Scheme (PCS). This enables developers to invest in phosphate reduction schemes such as wetlands to allow new homes to be built. This method of multi-sector working in Herefordshire, could be achieved in Wales to reduce nutrients from the food sector.

The collaborative approach of the Nutrient Management Boards is welcomed and is a strong foundation on which to build. Collaboration could go further, however, and all stakeholders in Wales, including customers, could have a role to play. Welsh Water are committed to playing our part in interacting with the Nutrient Management Boards process.

Whilst we proactively support the use of nature-based solutions to address water quality pressures, at present, we are unable to work directly with developers on nutrient reduction wetlands. This is due to the requirement for independent governance that underpins such schemes, and to ensure a catchment level oversight of all proposed solutions. We are working with Nutrient Management Boards and Local Planning Authorities to investigate where wetlands could be suitable, based on the catchment needs.

We are currently working with Nutrient Management Boards and Local Planning Authorities to investigate suitable sites. It is for the Local Planning Authority, Natural Resources Wales (in Wales) and Natural England (in England) to determine what nutrient neutrality is in each catchment, and how this should be calculated and demonstrated.

For more information on Natural England’s approach to recording and recognising Nutrient Neutrality, see their ‘Designing for Nutrient Neutrality’ Hub, available here.

Most Wastewater Treatment Works forecast to have a phosphorus reduction scheme to address our share of nutrient reduction, will be reducing the phosphorus to a low level. In these instances, a wetland is unlikely to deliver further treatment. We are including this in our discussions with Local Planning Authorities and Nutrient Management Boards.

Unfortunately, at this time, we are not in a position to adopt or manage privately delivered and privately funded wetlands.

Please be aware that they will require approval from both the Local Planning Authority and Natural Resources Wales or Natural England and Environment Agency.

All nutrient neutrality schemes and the benefit, or credits, that those schemes deliver will be managed by the Local Planning Authority and/or the respective Nutrient Management Board in your area, and as such you will need to contact yours for more information.

Our phosphorous reduction schemes at our WwTWs will not generate credits, the purpose of these schemes are to address our share of the phosphorous reduction required within the SAC rivers.