At the moment, final landscaping is being completed and official approval of the entire construction project is being prepared.
"This comprehensive remediation of a sludge basin is the single largest private investment into removal of old environmental hazard in Slovakia," said Ján Klimko, CEO and Chairman of the Board of Directors of ZSNP.
ZSNP has been one of the most important metal producers in Central Europe. Following its privatisation in 2002, Penta implemented a financial and operational restructuring, which resulted in a profitable and stabilised company it is today.
"As part of the privatisation, Penta has taken on an obligation to revitalise the land in and around ZSNP. That included remediation of one of the biggest environmental hazards in Slovakia, the formal sludge basin. The expected cost for the entire revitalisation at the time was EUR 16.8 million; the actual cost for the remediation of the sludge basin alone is higher by almost EUR 33 million," added Klimko.
The sludge basin had been used for producing aluminium oxide out of bauxite. Its comprehensive remediation included:
- constructing an underground bentonite wall to prevent leaks of alcaline waters into underground water
- treatment of alcaline water from the basin using two independent advanced technologies
- land reclamation – isolation and then re-inclusion of the former sludge basin into the surrounding environment
- Commencement: 2006
- Completion: 2012
- Expected cost for environment revitalisation at the time of privatisation: EUR 16.8 million
- Actual cost for remediation of the sludge basin alone: EUR 53 million
- Difference between obligation and actual cost: EUR 32.6 million
- 2004–2006 – extensive surveys for design of technology
- April 2005 – first comprehensive project presented
- May – December 2005 – expert evaluation of the project
- September 2005 – Advisory Committee of the ZSNP CEO nominated by the Slovak Minister of the Environment
- December 2005 – June 2006 – large scale tests to evaluate efficiency of proposed insulation and improvement layers
- April 2006 – updated project presented
- May 2006 – expert evaluation plus update with test results
- June 2006 – building permit for the sludge basin remediation project
- August 2006 – remediation commenced, expected implementation time 6 years
About the sludge basin:
- Founded: 1959 – 1967
- Area: 44.2 hectares
- Depth: 42 – 45 m
- Sludge volume: 9–10 million tons
- Alcaline water volume: approx. 1.2 million cubic m (as of 03/2005)
- 2 reservoir tanks – foot
- 5 pools – crown
- Perimeter: 3000 m
- Yearly water gain from precipitation: approx 80 thousand cubic m