Here’s the thing about sewer overflows. They are not going away.
There is a good reason why not – we need them. They are an essential part of our wastewater system. Without overflows, homes and businesses would flood during heavy rainfall. However, we can, and the industry is, taking steps to stop them from being used as often as they currently are.
Understanding Combined Sewer Overflows (CSOs)
We all want cleaner rivers and seas and what comes from stormwater overflows or Combined Sewer Overflows (CSOs) can take a toll on the local environment. And it’s not just ‘sewage’. CSOs release stormwater (the runoff after rain from the roofs, roads and urban areas) and household wastewater into the environment. This water carries sewage, heavy metals, plastics, oils, and grit. In addition, it collects slurry and pollutants from roads and hills. These issues receive less attention than sewage in national debate. None of it is good for biodiversity or our own health and well-being.
The necessity of sewer overflows
Sewer overflows activate when a treatment works becomes overwhelmed by the amount of water passing through its gates. As a result, the pumps can only cope with certain volumes of water, and eventually flows must be diverted to prevent the system from ‘backing up’. Overflows are the failsafe mechanism that stops the water flowing back through our toilets.
The heavier, more intense, the downpour of rain the more often overflows are used.
A modern approach to a widespread problem
The solution is to build. But not by simply pouring more concrete into the ground. Building new infrastructure is very much on water companies’ list of things to do in this new Asset Management Period (AMP 8). But so too is the need to build green infrastructure. Providing nature-based solutions to longstanding problems using innovative approaches that require less bricks and mortar are now the preferred approach.
Slowing the flow: Nature-based solutions
Southern Water’s strategy to reduce the use of CSOs, for example, is to slow the flow. This includes facilitating ways to manage rainwater where it falls and allow it to more gradually make its way to a treatment works, if it ends up there at all. Rain gardens, wetlands, planters and even the humble water butt can all be used to ease the pressure on the sewer system. The company’s various Pathfinder projects, trial areas for a variety of nature-based interventions, has seen wholesale changes to traditional approaches and different terms with which to evolve longstanding stakeholder relationships. Water is everyone’s responsibility.
Sustainable Urban Drainage Solutions (SuDs) are not new, but we are, as a more well-informed society, thinking about how we use them more effectively. The nature-based approach provides better outcomes for nature and for us. Therefore, it can also stop relentlessly kicking the can down the road in which new storage capacity eventually yields to the exponential pressures of climate change and population growth.
The future of wastewater management
The environmental impact of Combined Sewer Overflows will, over time, be much reduced. The water industry is changing, and natural solutions lay the ground ahead.
Copper Consultancy’s expertise is supporting the industry through a crucial period of change. Among many other areas, we are working on all things urban drainage via the Drainage and Wastewater Management Plans. We are cultivating meaningful stakeholder relationships now and for the future.