How robots are used to reduce sewage releases

Southern Water is using robots to inspect sewers in a West Sussex town as part of a £4m investment to reduce sewage releases into the sea.

The project will target Bognor Regis' main pipe which leads into the Aldingbourne Rife, a river and wildlife corridor that runs into the sea near Felpham Beach, where bathing water was last polluted on 17 March.

Robots will inspect sewage pipes across the town to identify problems before repairs and upgrades can be made.

Southern Water said it wanted to slow the flow of surface water entering sewers, which it said would ease the pressure on the pipe network to reduce sewage releases going into the sea.

"This particular part of the network affects Felpham Beach, so the overflow there we need to reduce to fewer than ten a year by 2027 as determined by our regulators", Nick Mills, head of environment and innovation at Southern Water, said.

"Storm overflows are unacceptable, we want to address them as quickly as possible, but it's a complex network which we need to understand and address.

"Once we've done these surveys, we will be spending £4m addressing where that excess [rain] water is getting in and putting it in the environment where it should be."

The Bognor Main pipe last had a sewage release on 5 January, which lasted more than 18 hours and polluted bathing water at Felpham Beach.

The government target for storm overflows is to allow discharges due to rainfall to be no more than ten times a year on average by 2050. Felpham Beach is one of the areas where Southern Water is trying to reduce sewage releases to fewer than ten a year.

But there are other outfall pipes not part of the £4m scheme which lead into the Aldingbourne Rife that can pollute bathing water at Felpham Beach.

For example, the Lidsey outfall pipe, three miles north of Bognor Regis, had 18 releases, totalling more than 332 hours, between 21 February and March 17.

Southern Water said it was looking to invest more than £8.5m in the next five years to prevent groundwater getting into sewers around the Lidsey outfall pipe, and that it was looking to upgrade the Lidsey treatment works to allow it to treat more wastewater, which could cost more than £50m.

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