Defra lists 140 WWTW that need to meet stringent nutrient stripping standards

Natural England has designated which English catchments are ‘sensitive’ under section 96C of the Water Industry Act due to being in an unfavourable condition as a result of phosphorus or nitrogen pollution in water (see map). Alongside, Defra has published a list of 140 wastewater works serving populations of 2,000 or more, that now legally need to be upgraded to meet stringent nutrient removal standards. These standards (10 mg per litre for nitrogen and 0.25 mg per litre for phosphorus) align with current Technically Achievable Limits.

Defra said the wastewater upgrades would enable the construction of thousands of homes and reduce mitigation requirements for developers. They will, however, come at significant cost for water customers.

In Poole Harbour specifically – an internationally important habitat for birds such as avocets and spoonbills – Natural England said phosphorous levels will be reduced to levels consistent with conservation objectives. It has removed nutrient neutrality advice for phosphorus in the catchment altogether, meaning developers will only be required to mitigate (via credits) for nitrogen pollution in future.

The list of wastewater works affected can be viewed here: https://www.gov.uk/government/publications/notice-of-designation-of-sensitive-catchment-areas-2024/information-about-nutrient-significant-plants