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Water sector stakeholders explore how the industry is already harnessing nature-based solutions – such as reed beds and integrated constructed wetland – to treat wastewater amid stretching new AMP7 targets and environmental scrutiny.

Despite phosphorus loading from water industry sewage treatment works to English rivers falling dramatically since 1995 and marked reductions in agricultural fertiliser use since the 1980s, “legacy” reserves in soil compiled over more than half a century demonstrate an ongoing phosphorus removal challenge, according to John Brewington, regional development manager at the Rivers Trust.

Speaking at Utility Week Live, industry experts explored how water companies are already trialing and deploying innovative new phosphorus management and removal techniques – including nature-based, biological and chemical approaches.

Severn Trent process engineer, Mathew Palmer, for example, explained that his firm has made a conscious effort to treat wastewater in line with the International Union for Conservation’s definition of nature-based solutions – “actions to protect, manage, restore natural or modified ecosystems to address societal challenges effectively and adaptively while providing other human wellbeing and biodiversity benefits”.

These include sustainable drainage system natural flood management, water abstraction management and ecological restoration and phosphorus reduction in sites of special scientific interest and reservoirs, alongside work to establish the use of reed beds – wetland areas which not only promote biodiversity but are effective in treating contaminated water due to the ability of reed plant roots to filter ammonia and phosphates – as a “standard option”.

According to Severn Trent, when contaminated or wastewater passes through a reed bed, plants catch the solid materials while organisms living within the beds naturally break down waste.

Importance of partnerships

Brewington also highlighted the value of collaboration in realising the potential of such nature-based solutions after recent Rivers Trust figures found that 0% of rivers are in good overall health, only 16% of rivers enjoy good ecological status, and since 1970, freshwater species globally have seen an 83% decline – faster than any other habitat.

Outlining the impact of United Utilities’ Catchment Systems Thinking (CaST) project in partnership with the Rivers Trust – which stresses looking beyond catchment areas towards broad solutions pursued in tandem with other landowners, businesses, regulators, NGOs and volunteers – on the River Petteril in Cumbria, Brewington explained that holistic and nature-based nutrient management partnerships had delivered an additional 10% phosphorus reduction beyond targets and £1.7 million additional natural capital benefits versus conventional solutions.

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In numbers: Rivers Trust, CaST and the River Petteril

  • £120,000
    Additional funding secured through match-funding and collaborative working
  • £7 million
    Value of estimated efficiencies in AMP6 and AMP7 across the Petteril catchment
  • £1.7 million
    Additional natural capital benefits delivered across the Petteril catchment versus conventional solutions
  • 10%
    Phosphorus reduction levels were 10% higher than target

As another example, Brewington flagged the success of integrated constructed wetland – man-made systems that use vegetation, soil and organisms to treat wastewater – collaborations such as the hectare-sized Ingoldisthorpe Wetland in Norfolk.

Built collaboratively between Anglian Water, the Environment Agency and the Norfolk Rivers Trust, the wetland uses four interlinked shallow cells and 25,000 native wetland plants. These absorb any remaining ammonia and phosphorus as water drains through each cell, before cleaned liquid is released into the River Ingol.

Save the date! Utility Week Live 2023 will take place on 16 and 17 May 2023 at the NEC in Birmingham.

Stay in the loop for #UWL23 ticket alerts, plus the latest industry and exhibitor news by signing up to our newsletter here