The Solent Mitigation Partnership is delivering a nutrient mitigation scheme through the upgrade of a council-owned sewage treatment works in Basingstoke.
Located within Basingstoke and Deane Borough Council’s administrative area and the Test and Itchen Nutrient Catchment, the treatment plant previously discharged nutrients into the local water environment downstream. These nutrients, nitrogen and phosphorus, ultimately flowed into the Solent, affecting water quality and sensitive habitats.
The upgrade involved installing a package treatment plant which now operates with improved treatment processes that significantly reduces nitrogen output. This reduction has been assessed and verified by Natural England, resulting in the generation of 70.01 nitrogen credits. These credits are available to help offset the applications requiring nitrogen mitigation in the eligible Groundwater Zone.
To purchase or reserve credits from this scheme, the development must meet both of the following conditions and fall within the schemes eligible boundary.
A river catchment refers to the area of land where rainwater flows into a specific river or stream; it includes the river itself and all smaller streams and tributaries that feed into it.
To be eligible, the development needs to be a groundwater draining development in the upper reaches of the Test and Itchen for nitrogen mitigation. This includes developments draining to Ludgershall, Ivy Down Lane (Oakley), Barn Close (Ashmansworth), Hannington, and North Waltham. It may also be able to serve some rural settlements that are a significant distance away from the rivers that rely on PTPs (please contact us for more clarification). This guarantees that mitigation is only sold to a development that also have a significant time lag impact for water reaching the Solent.
Only developments located in Basingstoke and Deane, north of Winchester and Test Valley, and a small area of west of East Hampshire and east Wiltshire are eligible for this scheme.
A former farmland site in Stubbington is now a nature recovery area, reducing nutrient runoff into the Solent. The project has generated over 400 verified nutrient credits to support sustainable development in the region.
The Solent Mitigation Partnership is working across Hampshire to deliver wastewater treatment works upgrades, enabling sustainable development.
A new scheme in Winchester will reduce nutrient pollution in the River Itchen by upgrading council-owned septic tanks. This will generate verified nutrient credits, helping unlock housing development while protecting the area’s sensitive ecosystems.
