Tideway's super sewer project is slashing transport emissions and combatting plastic pollution

The annual report for the Tideway super sewer project has revealed that more than 110,000 heavy goods vehicle journeys have been avoided and that more than 33,000 plastic bottles have been collected from the Thames river.

The latest report states that three kilometres of the 25km tunnel have been constructed

The latest report states that three kilometres of the 25km tunnel have been constructed

The Thames Tideway Tunnel is a new major piece of infrastructure for London. On average, 39 million tonnes of untreated sewage enters the tidal River Thames every year and if no action is taken, this is anticipated to reach 70 million tonnes by 2020.

The Tideway company has published its annual report outlining how the project is performing against an array of “legacy” goals, with the project designed to leave a lasting legacy of sustainability and economic prosperity for workers and the surrounding area. An independent social return on investment assessment of the legacy strategy indicates a £3.19 return for every pound spent on the project.


The latest report states that three kilometres of the 25km tunnel have been constructed. During construction, the project has mitigated anticipated pressure on London’s road network. More than 200 lorry journeys have been taken off the road each day, with the project instead utilising river transport.

More than one million tonnes of material has been transported by river, saving more than 115,000 HGV movements. Trials indicate that a 1,000-tonne barge produces an average of 90% less carbon dioxide than a standard HGV equivalent. The transport pillar of the project won edie’s Mission Possible: Mobility award at the 2019 Sustainability Leaders Awards.

Tideway’s chief executive Andy Mitchell said: “With work on the tunnel in full swing, and a continued focus on keeping people safe, our operations this summer will see a major increase in our river traffic.

“By transporting at least 90% of our tunnelling material by river instead of on the road, we are reducing our carbon footprint, as well as reducing road safety risks in London – two key issues for the capital. We are confident our work will lead the way in how businesses in future consider sustainable options for transporting goods and materials.”

Legacy performance

The report also updates progress against key metrics. More than 33,000 plastics bottles and 23,000 wet whips have been collected from the river’s foreshore, with assistance from Thames 21. In total, 90% of Tideway’s legacy targets are either on or above target – outperforming a predicted target of 75%.

The development of Tideway’s green bond scheme was jointly overseen by its sustainability and treasury team, with the product framework being independently assessed by S&P Global Ratings before it went to market. With the green bond market growing by a staggering 78% between 2016 and 2017, Tideway revealed that its Green Bond Framework achieved that joint highest global score by S&P of 95%. In total, £1.4bn of the financing for Tideway's £4.3bn 'super sewer' project is accounted for by green bonds

The legacy goals have been structured around the ambitions of the Sustainable Development Goals (SDGs) – including those related to gender, economic growth and responsible consumption. For the latter, 95% of all main material now comes from responsible certified sources such as FSC, PEFC, UK CARES and BES 6001.

Tideway was also featured on edie’s Sustainable Business Covered podcast. During the episode, edie talks to Tideway’s head of environmental sustainability Darren White before, during and after a boat tour of the River Thames, to discuss how a project to futureproof the city’s sewers will cut back on pollution and reduce plastic waste. Listen to the episode here.

Matt Mace


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