Solving storm release spills with systems thinking
Author: Chris Mannall, Head of water consultancy
The recent press coverage around sewage spills into watercourses has highlighted the scale of the challenge faced by water companies coping with the impacts of climate change and population growth. Delivering a better service to customers and the performance improvements required by Ofwat through the Outcome Delivery Incentives (ODIs) are driving the need to innovate and implement affordable solutions at pace. However, with funding constraints the challenges are complex and require multi-faceted solutions to extend the life of existing assets and optimise their performance.
Engaging with all stakeholders
While the water companies will be expected to drive solutions to address these complex problems, all stakeholders will have a part to play. This includes the public (as both users of the wastewater system but also as recreational users of water), regulators, operators and maintainers, farmers, designers, contractors and the supply chain. Education and information can play a huge part.
The water companies have sought to engage with the public on limiting what is ‘flushed’ to the sewerage system. However, wider education is still needed to improve understanding of the water cycle, how assets behave during storm events, what the impact of overflows are and what the risk to health might be. With the cost estimates quoted in the press for improvements to prevent the discharge of untreated sewage varying widely, better informed public debate is needed to determine what level and scale of improvements should be taken forward.
Progress is being made
It should be recognised that the industry takes the prevention of pollution incidents seriously as demonstrated by projects such as the Thames Tideway scheme with investment of over £4 billion to provide London with a new ‘super-sewer’.
Many water companies are making significant progress to reduce the number of pollutions. For example, between 2019 and 2020, across England and Wales there was a nearly 11% reduction in the number of pollution incidents per 10,000 km of sewer and further reductions in incidents must be achieved over the next three years as reflected in the companies’ AMP7 ODI targets.
In addition to reducing pollution events, companies must also reduce sewer flooding incidents and improve permit compliance at wastewater treatment works, challenges that are interlinked at the system level.
Beyond just the physical water infrastructure
The solution to this problem needs to consider not only the capacity of the sewer networks and treatment works, but also other factors such as the potential to generate and make greater use of data for more informed operation and maintenance strategies. Other factors at play include the impact of town and country planning decisions on our green spaces; public education on water use; decisions by the industry regulators and the positive effect funding and innovation can have on solving this problem.
A systems approach to understanding water networks
This multitude of factors means a move is needed from the traditional, linear approach to managing wastewater systems to a system-based approach that can handle the full complexity of the challenge. A systems approach could deliver greater value for money by ensuring that solutions are affordable and deliver the results that all the various stakeholders want and need.
In the long-term, cleaning up our rivers and estuaries must take in the wider impacts of land management and agricultural practice. Greater use of nature-based solutions such as Sustainable Drainage Systems (SuDS) and the restoration of our wetland and moorland habitats is vital. A shift is needed away from traditional, carbon-intensive solutions involving steel, concrete and chemicals towards nature-based solutions, which will enable the industry to deliver increased biodiversity and generate new amenity value for society as a whole.
The use of geographic information systems (GIS) technology can capture, manage, and help visualise location data into a comprehensive analysis and decision-making tool. This technology is used in Digital Biodiversity Management (DBM), which improves programme delivery certainty, helps reduce biodiversity losses and optimises opportunities for greater net gain. This means greener infrastructure for our planet and communities.
Asset optimisation to support network resilience
Asset optimisation can help to reduce the risk of pollution events by ensuring existing assets are maximised and efficient. By understanding the construction, operation and maintenance of the existing treatment assets, it is easier to determine if further investment is needed and whether the overall process has been optimised.
Real-time insights can also improve work scheduling to automate the management of maintenance work giving insights into productivity and areas for improvement. Not only does this build a more resilient network but also shifts from reactive to more cost effective, predictive maintenance programmes.
Improved use of data
A starting point for meeting the pollutions challenge is the improved use of existing data. When combined with machine learning, the time taken to complete investigation work can be halved when compared to traditional hydraulic network modelling methods. This not only speeds up the process of understanding the wastewater system’s performance but means more accurate and timely decisions can be made for both immediate remedies and future investment.
Digital solutions to identify the cause of pollution events
Each catchment will have its own unique requirements and therefore needs a bespoke solution that focuses on addressing a combination of factors. Costain process engineer, John Cannon, is leading a project in the UK looking at the use of machine learning and operational insight to understand individual catchment challenges; to identify the root cause of pollution events and to efficiently drive cost-effective solutions.
Machine learning has the capability to rapidly study, compare and draw insight from numerous existing data sets and use existing operational telemetry data to model the impacts of different scenarios. This can also include rainfall, water table and tide data to understand actual localised responses. The project has the potential to identify infiltration hot spots, catchment flow balancing opportunities and the relevant levers that companies can adjust to prioritise investment levels and outcomes.
So, what is next? With three years remaining in the AMP7 cycle, water companies and key stakeholders need to consider how to better analyse all the different systems together, upscale nature-based solutions, improve education and accelerate digitalisation. All these components will help maximise the investment in the water network to ensure that the industry is not only fit for the future but also recognised by the public as being environmentally responsible and sustainable.