A nature-based approach that improves water quality

Southwaite Integrated Constructed Wetland, United Utilities

Looking for innovative solutions is part of doing what’s right for the environment and our clients. A unique project—Southwaite Integrated Constructed Wetland—shows how innovative nature-based solutions can work to help wastewater treatment integrate into the local eco-system.

Meeting the requirements for the Water Framework Directive presents a significant challenge for wastewater management in the United Kingdom. In Cumbria, the Southwaite Wastewater Treatment Works treats the flow and load from Southwaite, including the M6 Motorway Services. Commissioned by United Utilities, we collaborated to provide a hybrid solution that combines the best features of conventional treatment and nature-based solutions to help reduce flow and improve water quality at the site.

How does it work? The wetland was designed exclusively to treat storm spills. As flows increase, the treatment configuration changes. Flows bypass the conventional treatment, and the wetland accepts and treats flows. The wetland is configured to both attenuate—slow the flow—and treat the flow. This combined solution strengthens treatment during storm spills and achieves water quality objectives.

Now, with reduced nutrient pollution, the watercourse is improved and biodiversity in the wetland is enhanced. This hybrid design has helped United Utilities drive efficiencies while considering what is best for the environment.