Water and the circular economy: stemming the flow of climate change impact
The transition to a circular economy is not only better for the environment. It allows water companies to more effectively address key challenges of ageing infrastructure and affordable water supplies, explains Andy Sang, director of infrastructure at Sweco UK.
Climate change is one of the most urgent and pressing challenges facing our planet. And the built environment is notoriously high polluting – in the UK alone, it is responsible for around 40% of the country’s total carbon footprint.
Organisations across the sector are under pressure to reduce their environmental impact, including water companies. Embracing water engineering innovation, and taking steps to future proof infrastructure, will be key to driving down emissions. Any investment must, however, be cost-effective, and currently, the challenge for the engineers delivering these solutions is to ensure they are workable, able to satisfy the complex requirements of water and wastewater infrastructure projects while still championing efficiency.
One potential solution is ‘going circular’, an approach that directly challenges the traditional ‘take make waste’ model of development, and instead ensures any resources and materials remain in a functional cycle as long as possible. The concept of waste is eliminated, with all materials considered a resource.
The benefits of combining water and the circular economy are twofold. Developing circular economies helps to reduce carbon consumption with its focus on reuse and regeneration. But, critically, going circular also helps to protect our urban environments against the impact of climate change – in particular, the increasing frequency of heavy rainfall.
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This is where the pivotal role of the water industry comes into play. Increasing rainfall is a key consequence of rising global temperatures and a big challenge for our cities where water can run off as much as 10 times faster than on unpaved land.
Restoring the natural landscape and making it a function of our built environment is an important ‘circular’ solution, promoting local drainage and more effective management of excess water flow in urban spaces.
Rain gardens are a practical – and aesthetically pleasing – means of achieving this. As well as being easy to retrofit, their naturally flexible layout means they can be introduced to virtually any landscape, mimicking the water retention properties of undeveloped land.
Their success in managing urban drainage means they are becoming commonplace across several Scandinavian countries. Kviberg, Gothenburg, for example, is home to Sweden’s largest rain garden, which can manage rainwater from a 15,000 sq m area. Rainfall that flows into the garden from an adjacent parking area is collected in rain beds, and is then filtered and purified, restoring the natural water cycle and allowing it to be captured and reused elsewhere.
Another method, known as daylighting, is an effective means of introducing surface water management into urban environments. This practice restores underground waterways to the surface, allowing them to form part of natural drainage systems. An example of this in practice can be seen in Skytterdalen, Bærum, west of Oslo, where a stream has been fully restored and is now used to separate clean surface water from wastewater. Flowing through a redesigned stream course built from moraine masses, it now has the capacity to withstand a 25-year flood.
Reusing water on site is also a key facet of circularity. Where water is a scarce resource, introducing methods to capture, clean and reuse it are vital to ensure adequate supplies.
The Biozone Ootmarsum in the Netherlands is a man-made wetland designed by Sweco, which converts the effluent from several wastewater treatment plants into clean water, that can then be reused in the natural environment. The purpose of the biozone is to oxygenate the water, reducing ammonia and eliminating other pollutants, and is formed through a series of aquatic and marsh plants, meaning it blends seamlessly into the surrounding landscape.
At the same time as facing pressure to respond to the growing issue of climate change, the water industry faces its own challenges. Across the UK, our water and wastewater infrastructure is ageing and replacing it is a costly and time-consuming exercise, which directly impacts the accessibility and affordability of clean water.
Adopting circular practices is therefore critical not only to guarantee environmental sustainability, but to safeguard and futureproof our water services through reduced reliance on physical pipework and offsite storage and management, in favour of local drainage.
On a practical level, the next step to make circular practices a reality is embracing technologies such as artificial intelligence (AI) and building information modelling (BIM). These are critical in the very earliest design stages, helping water companies model multiple potential approaches and understand the advantages and disadvantages of any design decision instantly.
In addition, tools such as BIM deliver insights into net carbon emissions, upfront costs, and the potential for reuse, recycling and upcycling throughout a project’s lifecycle – another key component of circularity.
With the need to address climate change so urgently, water companies have a significant opportunity to lead the charge when it comes to transitioning to a circular economy. Adopting circular practices and championing a design and delivery approach underpinned by technology will deliver the best possible outcomes for customers and the environment.