Crawler robots helping to prevent flooding and pollution

Water UK has found that non-flushable wipes make up around 75 per cent of sewer blockages. Some manufacturers claim that their wipes are flushable, but this assertion is challenged by those tasked with helping to clear the blockages.

One such person is Alex Hartley, a Resolution Support Technician in Complex Investigations and Resolutions at Anglian Water.

The Complex Investigation and Resolution team was created after a particularly wet winter to find the root causes of repeat floodings and pollutions, which Anglian Water defines as ‘any escape of wastewater or potable water from our assets which could have a detrimental impact to the environment.’

Reporting to the Tactical Asset Strategy team, Hartley and his colleagues are in possession of a range of high-tech tools to make inspections and report on misconnections and infiltration points that are adding excess water to the network.

These include CCTV camera vans that receive visual information from a Minicam crawler robot that is operated from within the van.

Another key piece of kit is WinCan sewage inspection software that provides a range of advanced tools for collecting pipe inspection data, organising it in a database and generating reports that graphically depict the pipe and its defects. 

The Engineer joined Hartley and his team on January 15, 2025 to observe an inspection of a sewer pipe in Wyboston, Bedfordshire, in January.

The job involved a contractor jetting the pipe with highly pressurised water to clear it, but for certain jobs a chain flail is sent down to remove solidified fat.

Then, the circa £30,000 crawler – tethered to 250m of fibre-optic cable – is lowered into the pipe to perform an inspection, using its pan and rotate camera to look for any anomalies that are recorded by the operator and uploaded onto WinCan. This information can then be passed onto Anglian Water’s Network Teams to resolve any issues.

“These camera vans…allow us to survey all the sewers, code it all, and then at the end of it, compile a report based on what we've found,” said Hartley. “Then we can present it to the IMR - our repair team partners - and say, ‘this is what we found’, and they make the decision whether to assign funding.”

Another tool in the box, beside satellite data and sniffer dogs (yes, sniffer dogs), is a drone, a piece of kit that was used by Hartley to pinpoint a pollution on January 14, 2025. More normally used to conduct ‘more serious’ pollution surveys, Hartley flew the drone to provide his managers with aerial footage that could be presented to the Environment Agency (EA).

“We had a rising main pipe burst in a village near Northampton,” he said. “I got permission from the local landowners, and then flew it up, took some videos of the impact point of where the sewage was. Then, because we had quite a lot of tankers on site, our regional manager wanted some pictures of the tankers to show to the EA what we were doing to mitigate the effect of the pollution, and they also wanted footage of where the samples had been taken from. What we did was get the guys to stand where sample point one, point two, and point three was, and then I flew the drone over the top. You can just see it’s better than a photo from on the ground.”

Misconnections and infiltrations

A survey in Cambridgeshire highlighted the issues associated with misconnections and infiltrations, bringing with it complications around who or what takes responsibility for flooding and drainage.

Yaxley is in the Fens Basin and is a few metres above sea level, making it prone to flooding. Anglian Water have mitigated against this with tankers, but their use is expensive, disruptive and doesn’t address what is a long-term problem.   

However, with the resources available to the Complex Investigation and Resolution team it was possible to accurately pinpoint where misconnections and infiltrations were taking place.

The survey found that Yaxley and the nearby village of Stilton had over 60,000m2 of misconnected rainwater pipeline. These surface water misconnections had largely occurred where downpipes from homes or highways road drains had been wrongly connected to the foul sewer, reducing its capacity and causing flooding. 

They also found around 1,000 infiltration points that were putting ‘significant pressure’ on the network.  

Fines for pollutions

Back Chawston near Wyboston, Hartley and his team are coming to the end of their survey, which was instigated by customer internal floodings caused by infiltration of groundwater in the sewage network.

“We are cleaning the sewers that we've not been able to get the camera through due to grease build up or debris, which is what we do towards the end of survey because we first identify what sewers need cleaning, then what sewers we can survey without getting them cleaned.”

Hartley added that cost of a camera van is likely similar to that of a new sports car, but investing in the capability is likely to save money. From 2026, UK water companies can face fines of up to 10 per cent of their annual turnover for pollution violations. Anglian Water says it categorises pollution incidents based on their severity, typically using a system with categories ranging from 1 (most serious, causing significant environmental harm) to 4 (minimal impact).

“So category three pollution is going to cost somewhere in the region of £250,000 as a cost to the business,” said Hartley. “If this van could save just one pollution happening then it has is paid for itself three times, hasn't it? In terms of a cost saving exercise it's is a no brainer.”

He continued:  “The amount of the amount of stuff we have found with it is invaluable to the business, going forward for them. That overall benefit from reducing our pollutions and effect on the environment is where we're going to save the money and not get penalised.”