Flushing roulette: Southern Water installing digital sewer monitors to prevent blockages

Where's there's muck there's brass, and there won't be many places more mucky than a sewer system as bidders for a network digitalisation contract in southern England are about to rediscover.

According to a tender published this week, Southern Water is wading through the market to sniff out a supplier to "significantly and rapidly improve the visibility of the gravity wastewater network."

"We plan to achieve this by installing 10,000's (up to 30,000 across Kent, East and West Sussex, Hampshire and the Isle of Wight) of sewer monitors and developing in parallel the associated analytics to make appropriate and effective use of the additional information to prevent sewer blockages developing into a pollution or flooding incident," the document states.

"Therefore the objective of this tender is to ensure that the successful tenderer(s) can deliver the full scope of the work to provide sewer level monitors across SWS's (Southern Water Service's) requirement," it adds.

In return, the winning bidder or combination of bidders will receive up to £8m over the four-year lifetime of the agreement, ending August 2025. Up to five suppliers will be considered for inclusion, any remaining will be flushed.

The framework agreement is to be split into three lots: sewers survey and sewage treatment consultancy services; sewerage management services; and sewer survey services.

Publication of this tender comes after a court ruling in May that fined Southern Water a record £90m for intentionally dumping between 16 billion and 21 billion litres of raw sewage into the sea off Kent and Hampshire to avoid financial penalties and the expense of upgrading and maintaining infrastructure.

However, a spokesman for the company said the tender for network digitalisation and the fine are not related.

"This project is vital but unconnected to the fine recently levied on the company for historic permit breaches at wastewater treatment works between 2010-15. Since those breaches were discovered the company has been in a major transformation of culture, people and processes."

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He added: "Network digitisation is central to our commitment to reduce the risk of blocked sewers and the pollution incidents they can cause.

"Sewer pipes connecting homes and street to the much larger sewer mains are easy to block with wet wipes, fat oil and grease and other so-called unflushables and this is a leading cause of incidents."

Under the plans, thousands of digital monitors are to be installed across Southern Water's 39,500km network as part of a "major project" to "monitor the level of flows in pipes."

"Drops in flow will indicate a fat berg forming and enable us to send crews to jet the pipe before it blocks completely leading to sewage overflowing manholes or even into homes, businesses and public buildings such as schools and hospitals," Southern Water's spokesman added.

As for the court case in May, Mr Justice Johnson, who oversaw proceedings, said: "These offences show a shocking and wholesale disregard for the environment, for precious and delicate ecosystems and coastlines, for human health, and for fisheries and other legitimate businesses that operate in coastal waters."

He said Southern Water has a track record of "previous and persistent pollution of the environment," and with 168 past offences and cautions under its belt, "it's offending simply continued," he added.

Southern Water hid its actions by "very significant under-reporting," the judge ruled.

This was said to be the worst environmental crime in the quarter-of-a-century history of the Environment Agency. Justice Johnson said the company's "co-operation was grudging, partial and inadequate."

Southern Water pleaded guilty to 51 counts between January 2010 and December 2015 of "knowingly permitting entry to coast water of poisonous, noxious or polluting matter or waste matter or sewage effluent… otherwise than as authorised by an environmental permit," the report said.

The company provides water to 2.6 million customers and wastewater services to over 4.7 million customers in the English counties of Sussex, Kent, Hampshire, and the Isle of Wight.

The privately owned business made £139.6m in pre-tax profit in fiscal 2021, versus £213.2m in the prior year. It reported revenues of £784.2m versus £878m. ®