232 140 m2
454 710 m2

LOCATION Žiar nad Hronom, Slovak Republic

INSTALLATION 2007 – 2010

Aluminium has been produced in Ziar nad Hronom since 1953. Until 1998, alumina (the basic chemical compound required for aluminium production) was refined here by a relatively demanding manufacturing process directly from bauxite. After it’s extraction, the remains left from bauxite processing were hydraulically transfered into a residue disposal site located nearby the manufacturing plant where the solid components settled, whilst the water was returned for further use within the technological process. During the period 1957-1997, a massive sludge bed was created here, currently occupying total area of 44 hectares. The height of the sludge corpus is 42-45 m, the perimeter is approximately 3 kilometres. The overall volume of sludge deposited here is abt. 10 mil. tons, the prereclamation contents of water (partly originating from the transporting processes, partly from rainfall) was approx. 1,2 mil. cubic metres.

Over the years, this sludge water, with its high level of alkalinity, became a serious threat for the surrounding environment. A necessity arose to secure appropriate cleaning procedures and, at the same time, to prevent further volumes of rainwater from penetrating into the sludge corpus in the future (a technical reclamation).

The reclamation works consisted in the installation of an impenetrable layer in the area of the sludge corpus cap, the sealing of leakage and gravitation canals and subsequent sealing and coverage of slopes. The sludge bed foreground was also shielded by an impermeable layer. As soon as all the reclamation procedures are finished, the sludge bed will be protected against further penetration of rainwater and repeated emergence of highly alkaline water will be avoided. The sludge corpus will acquire a high level of stability and the risk of solid particle entrainment will be also eliminated.

For the sealing of sludge corpus cap and the sludge bed foreground, waterproof membrane JUNIFOL PEHD (thickness 1,50 and 1,00 mm) was used. Non-woven geotextiles geoNETEX (area weight 200, 500 and 800 g/m2) were also installed in diverse parts of the sealing systems – in order to fulfill separation, filtration and protective functions, respectively.

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