Southern digitises sewer network

Southern Water has added 22,000 monitors across its wastewater network as part of a “revolutionary” project to cut pollution incidents by 2025.

The company has installed monitors to detect when blockages or faults are developing to allow teams to respond quickly before a flooding or pollution incident occurs.

The sensors, together with an artificial intelligence system, target unflushables from homes and businesses including wetwipes, fats, oils and grease, and other items that should not enter the sewer network. These contribute to more than 80% of blockages in Southern’s network, therefore locating and removing them will be “a real game-changer”, according to head of wastewater networks Alex Saunders.

“The revolutionary technology will mean we can respond proactively instead of waiting for sewers to block,” Saunders said, and explained that blockages can be detected and found within hours rather than the several days it would have taken previously.

Southern is investing £15 million in the monitors, which are part of the company’s work to drive down pollution incidents by 40% by the end of this regulatory period in 2025.

To achieve that ambition, the organisation’s efforts are targeted in three parts: across sewer networks, at pumping stations, and at wastewater treatment works. Through monitoring Southern hopes to stop blockages before they impact the pumping and treatment sites. Last year pollution incidents were halved at pumping stations across Southern’s region.

The company reported 3,944 external flooding incidents, which is below its target of 4,141.

Two types of monitors are being used, one suitable for down to three metres and another that can go further. These will feed readings back every 15 minutes to Southern’s systems, which are combined with data from Stormharvester on rainfall and weather predictions. The AI determines where and when potential problems may occur and, depending on rainfall, indicates whether flows are within a normal range for that location and weather patterns.

The monitors will measure flow level and the AI, after spending up to three months “learning”, to understand the normal levels or when to trigger an alarm.

Richard Martin, head of operations and controls, added the move from reactive to proactive sewer monitoring and maintenance will help the network, as well as pumping station and wastewater treatment plant assets, function optimally.

The information from the system will also be used to inform investment decisions and planning as part of the company’s strategy to minimise the risk of harm from pollution incidents and improve river health.

The digitisation is the first at scale in the UK but builds on work done by others in the sector to add monitors and enable data analysis through machine learning to sewers.