Articles & Case Studies

Thames Water invests £24 million in Hydro Sludge Handling Technology

Posted: Tuesday 17th April 2012

Thames Water is investing in innovative Zickert sludge handling technology from Hydro International in record-breaking contracts totalling £24 million at its major sewage works in London.

Hydro’s Zickert continuous bottom scraping and surface scum removal technology will collect sludge from a total of 53 primary settlement tanks at Beckton, Crossness and Mogden sewage works. The projects are designed to increase sewage treatment capacity, improve operating efficiency and reduce odour.

In the largest project underway at Beckton STW, a total of 24 existing sedimentation tanks will use new Zickert sludge scrapers, adding to eight existing Primary tanks already converted to the Zickert system. The complete £16.5 million installation will cover more than 56,000 square metres – equivalent to more than 11 football pitches.

Thames Water is making the investment in Zickert top and bottom sludge scrapers based on the proven performance of existing installations.

Zickert offers significant advantages over conventional sludge scraping technology with lower operating and infrastructure costs. The gentle action of the Zickert equipment produces a higher yield of sludge than conventional scrapers. Its higher throughput reduces the amount of secondary treatment required and produces more primary sludge with a higher calorific value for incineration.

As the Zickert tank design requires a much lower headroom than other sludge collection equipment, its low profile reduces the volume of air to be treated for odour removal within the tank enclosures, improving process efficiency.

Work has also begun at Mogden to retrofit eight primary settlement tanks and to equip five new tanks. This forms part of Thames Water’s £140 million upgrade to increase sewage treatment capacity at the site by 50 per cent. The contract is awarded by Black and Veatch.

At Crossness STW, eight new primary settlement tanks are being built as part of the £220 million upgrade increase sewage treatment capacity by 44 per cent at the site. The Zickert equipment will be installed early in 2012 to provide energy-efficient odour control and deliver sludge to provide 20% of the plant’s energy needs. The contract is awarded by Tamesis, the Laing O’Rourke and Imtech Process Joint Venture.

The Beckton Zickert project has been awarded to Hydro by main contractor GBM, the joint venture of Galliford Try, Biwater Treatment and Mott Macdonald. Says GBM Project Manager Phil Muir:

“Thames Water decided to use Zickert scrapers for primary treatment to replicate the good performance and reliability of the existing Zickert tanks installed at Beckton in 2007 and 2009. They recognised that the Zickert process was a good one for wider upgrade of the facility.”

“These contracts together are a record breaker - the largest ever placed with Hydro,” said Chris Day, Operations Director of Hydro International Wastewater division. “It’s a true vote of confidence in Zickert technology which has been proven in use in the UK for 15 years. We are expecting other water companies in the UK to follow suit.

“Already the first Scottish installation of Zickert sludge treatment technology is underway at Hamilton WWTW, South of Glasgow as part of Scottish Water Solutions upgrade there.”

For more information about Hydro Zickert technology or any of Hydro’s innovative Wastewater treatment solutions call 01353 645700, or visit

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