Panoramic view of the River Stour from the opposite bank — Lewis Clarke / Bournemouth: The River Stour / CC BY-SA 2.0

Investing in Green Infrastructure for Surface Water Quality

UK, Europe

Primary Implementer

Anglian Water

Eastern England

Europe

Website

South West Water

Contact Email

johndoe@ucsb.edu

Anglian Water is a water utility that covers the largest geographical area in England and Wales (east of England and Hartlepool), covering 20 percent of the land area of the two regions (27,476 square km). The service area is located in a comparatively low-lying region and receives, on average, a third less rainfall than the rest of England. The company, privately owned and managed, supplies 4.3 million people with drinking water and collects and treats wastewater from over 6 million people across the area. Due to the agricultural nature of the area, each year Anglian Water spends substantial amounts of money removing pesticides from drinking water to ensure compliance with the standards set out in the EU Drinking Water Directive (DWD). This has potential implications for customers’ bills as well as energy and chemical use.

Close-up of a cute baby fox leaping on meadow — © TNC

Challenges

Anglian Water faces a number of environmental challenges in a high-growth, water-stressed region. One of the challenges met by Anglian water in its catchments is metaldehyde, a highly soluble, organic compound commonly used as a pesticide against slugs and snails. Another challenge for Anglian water was its Ingoldesthorpe Water Recycling Centre, a wastewater treatment plant managed by the company which is located on an important site for biodiversity. The high level of ammonia and phosphorus at the site exceed the European Drinking Water Directive (DWD) standards.

Bear swimming toward a school of fish — © TNC

Financing

The Slug it Out campaign scheme costs are largely influenced by market prices for the cost difference between the pesticide products. The scheme was funded by Anglian Water through its opex programme (and therefore through tariffs). The pilot trial was delivered for a total cost of £3.5i. It would require significant scaling up to cover the 8,500 farmers who manage land across high-risk portions of the water company’s service area. By comparison, installing treatment for the whole region affected by metaldehyde would cost as much as £595 million, which would significantly impact customer bills.

Anglian Water financed the entire Ingoldesthorpe Water Recycling Centre project and invested £500,000 in constructing the artificial wetland. The success of this pilot led the company to further promote NbS, both internally and externally to industry regulators. The company proposed the development of several wetlands for waste water treatment in its business plan for 2020-2025. For this period, the company proposed a further £800 million worth of investment in enhancing and protecting the environment, which is more than double that of the previous five years’ plan. If approved by the economic regulator, Ofwat, as many as 59 treatment wetlands could be built in the coming years. A key challenge will be to redesign Anglian Water’s procurement systems, which are designed to contract large engineering firms rather than smaller, local level organisations such as river trusts.

Actions & Impacts

“Slug it Out” campaign

Anglian Water launched the Slug it Out campaign in 2015 with the aim of reducing metaldehyde levels in the region’s waters before they reach the treatment works. It is an example of a catchment management approach as opposed to an ‘end of pipe’ solution. Slug it Out” provides incentives to farmers to change their practices, paying them the cost difference between metaldehyde and alternative chemical slug controls containing ferric phosphate as the active ingredient. Ferric phosphate pellets are typically more expensive than metaldehyde, but ferric phosphate is not soluble and can therefore be removed through conventional water treatment. Farmers needed to be sure ferric phosphate products would be effective A key influencer in this debate is the way in which the two types of pesticides operate. While metaldehyde kills slugs by desiccation (so that they remain visible on ground surface), ferric phosphate makes slugs sensitive to light: they hide and die underground. As a result, they are less visible to farmers, who may wonder if the product has been effective. In fact, both products are effective against the target species and work at the same speed. The campaign allowed farmers to experience the alternative ferric phosphate products on their own land so they could see its effectiveness for themselves.

Another key success factor was that Anglian Water employed a team of agricultural experts to engage with farmers rather than use existing staff. These experts advised the company on farming practices and brokered relationships with farmers, whose business they understand. The campaign runs across several Anglian river catchments and involved 216 farmers working 22,500 hectares. From 2015 to 2018, the trial led to a 94 percent drop in levels of metaldehyde detected in reservoir waters. In 2019, the majority of raw water reservoirs within the trial area were compliant with DWD standards.

Constructed wetland at Ingoldisthorpe Water Recycling Centre

In a drive to achieve the standards of 1 micron/litre for ammonia and 4.5 micron/litre for phosphorus, Anglian Water engaged with the Norfolk Rivers Trust, a local charity focused on catchment-based approaches. River Trusts are independent community-led charitable organisations delivering water management advice and practical work for the conservation and/or restoration of land, rivers, and wetlands at a catchment scale.
With financing from Anglian Water, the Norfolk Rivers Trust built a wetland treatment site between the autumn of 2017 and the spring of 2018 at the Ingoldisthorpe Water Recycling Centre. The wetland filters water after it has passed through the existing treatment plant to ensure it meets high quality standards, thereby replacing the need for conventional, energy-intensive infrastructure. This green infrastructure works as a natural treatment plant for millions of litres of water a day and helps reduce ammonia and phosphorus in the catchment: partially treated water passes through the wetland to be further filtered and cleaned before it returns to the River Ingol. This type of natural infrastructure has the potential to generate cost savings, reduce carbon emissions and increase wildlife in the area. Early results show that water quality has improved beyond expectation and that wildlife thrives in the newly created natural environment.

References

IWA. (2018). Nature-Based Solutions Utility Spotlight: Anglian Water.

Norfolk River Trust. (2018). River Ingol Wetland Creation
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Anglian Water. (2019). Our Business Plan 2020-2025.
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