Leaf it out! Teams root out tree blocking sewer

When teams were tipped off by our artificial intelligence sewer monitors that a blockage was growing in Lower Halstow near Swale in Kent they knew they ‘wood’ have to act fast.

Even more so when they found the cause of the problem was a tree’s root which had grown through the wall of the pipe and was quickly expanding as it sucked up the water.

“I had all the puns lined up for this one,” said Daniel McElhinney, Proactive Operations Control Manager at Southern Water, “But I’ve been told by the team to leaf it out and stick to the day job because I’m not the branch manager“.

He continued: “In fact, roots puncturing or blocking pipes are a known cause of blockages. Since the start of April, we’ve dealt with 47 instances. Of course, that is dwarfed by the 1729 caused by wet wipes and other unflushables – which along with fat, oil and grease wrongly disposed are by far and away the biggest cause of sewer pollutions,”

The root cause in Lower Halstow was detected thanks to some of the around 34,000 sewer lever monitors on our network.  We can constantly check on flows and spot anything out of the ordinary which might highlight a blockage or leak.

Dan added: “The sensors measure the level of sewage flowing under manholes in blockage hotspots, but the real innovation is how machine learning or artificial intelligence learns the normal behaviour of sewers and can tell the difference between morning and evening rushes, rain in the system and a blockage forming.

“Instead of turning up after the event to clean up and commiserate with devastated customers we’re spotting hundreds of potential blockages before it’s too late so our teams can scramble round with high pressure water jets to clear the sewer.”

Most customers do not realise the average suburban sewer is only the diameter of an orange or a tennis ball. It doesn’t take much cooking fat to combine with other ‘unflushables’ such as sanitary products, wet wipes or even ear cleaning sticks, to form a fatberg.

After detecting sewer blockages, our teams call round the neighbourhood to tell them about close calls and educate them on how to keep sewers flowing freely.