HS2 – G2S South and Central Sections

Siltbuster’s infrastructure water treatment specialists are supporting civil engineering joint venture EKFB with water treatment systems at its sites along the HS2 high-speed railway project. The customer is one of the four joint ventures, delivering around 80 km of infrastructure for the scheme.

So far, Siltbuster has supported with two-stage chemical treatment solutions at more than 60 EKFB sites, with systems ranging from 50 to 180 m3/h.

As part of a regular series of check-ups and meetings EKFB approached Siltbuster for several system upgrades in the G2S South and Central Sections of the route. Due to the progress of the work and the purchase of additional land, the main contractor needed bigger systems which meant upgrading the existing 50 m3/h to 120 m3/h systems with some locations being upgraded to 180 m3/h.

Compliance and a reliable setup were key to meeting the challenge. The criticality of the work and the tight time schedule meant the client could not afford any downtime or delays due to insufficient water management.

There are very stringent discharge criteria for HS2 for the management and treatment of surface water. Surface water is usually captured in attenuation lagoons before it goes through a two-stage treatment system, removing sediments and neutralizing pH before discharging into water courses. Both Siltbuster and EKFB had to adhere to a strict pre-agreed schedule and sequence of works to prevent environmental pollution while the systems were out of operation.

The plan looked also logistically challenging. Equipment had to be drained, cleaned and disconnected, lifted out and moved from locations that proved difficult to access and recommission the systems.

Siltbuster and pumping solutions specialist Selwood, our sister company in the Workdry International Group, worked closely together all the way from early engagement until completion of the project. The solution is the same two-stage treatment systems that have already been installed on site, but at a larger capacity, enabling the contractor to meet the additional water treatment demands.

The water was treated with either a Siltbuster MT30 mix tank or a 6” pipe flocculator and four HB40 lamella clarifier units, designed and manufactured at Siltbuster’s headquarters in Monmouth before being transported to site where they operate on a plug and play basis. Where pH correction is not required Siltbuster can supply a 6” pipe flocculator instead of a mix tank which due to its light weight and compact size makes it easier to accommodate on site where space and lifting equipment are limited.

In this type of solution, coagulant and flocculant chemicals are mixed with the water in the 6” pipe flocculator to encourage particles to bind together. Then, in the lamella clarifiers, water flows upward between inclined plates. The larger combined clay particles settle on the plates and slide down into hoppers in a sludge collection area where they can safely be removed. After treatment the water was then discharged into the nearby surface water ditch.