Crossrail – Tunnelling Academy Chooses Siltbuster

25 Jul 2013

The Tunnelling and Underground Construction Academy (TUCA), in Ilford, East London has chosen a Siltbuster system to neutralise high pH water produced during concreting lessons, as the purpose built facility trains up a new generation of underground specialists.

The high profile Academy, the only soft-ground tunnelling training facility in Europe, is being co-funded by Crossrail and The Skills Funding Agency, to the tune of £12.5 million. It is designed to supply the large number of skilled and qualified workers needed to service the major construction projects across the UK.

At the Academy students are put through a five-day course on tunnelling and over its lifetime it is expected to train at least 3,500 people.

An integral part of the course is learning to handle sprayed concrete, with a considerable amount of continuous concreting activities taking place year in year out. These lessons bring with them the need to regularly washdown the school’s large range of concreting equipment and so the Academy chose a Siltbuster PMPU20 to treat the resulting concrete wash water and demonstrate Best Practice.

The Siltbuster PMPU20 is designed to automatically adjust the pH of water and operates in three process stages. Using carbon dioxide vapour, the highly alkaline pH of the concrete wash water is initially reduced from in excess of pH12 down to around pH10. An integrated Siltbuster clarifier is the second stage and this captures suspended or precipitated solids in the water, safely removing the cement particles prior to discharge. The water then passes into a final tank for treatment again using carbon dioxide, where the pH of the water is reduced further down to neutral (pH7).The water is then discharged or reused, leaving a minimal amount of solids for disposal.

From a scientific point of view the Siltbuster system has some other major advantages. The risk of over dosing, and discharging water with a pH of less than 6 is virtually eliminated thanks to clever chemistry and an integral automatic dosing system. With acid based systems, it is easy to continue reducing the pH below 6 and risk creating and discharging acidic water, something which is environmentally unacceptable in today’s climate.

The use of carbon dioxide rather than acid to neutralise the water also means that students do not need to handle strong mineral acids; there is no risk of dangerous spills, and no acid disposal issues to consider.

Commenting on the Academy’s decision to use Siltbuster, Richard Coulton, Managing Director of Siltbuster Limited said: “TUCA is setting the global standard when it comes to best practice in tunnel excavation and underground construction. To see our technology used in such a prestigious facility is a fantastic endorsement of Siltbuster’s equipment, our own highly experienced scientists and engineers, and the years of effort that has gone into developing this system. It’s also great to know that tomorrow’s tunnelling specialists are learning not only how to place concrete but also how to treat the associated washdown water and minimise its effect on the environment.”

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