Combined techniques save Czech spa
As the Czech Society for Trenchless Technology (CzSTT) celebrates its 10th anniversary, chairman Prof Milo R Karous, who is also president of Geonika, reports on a model EU joint-venture project to rehabilitate the century old sewerage network of Mariánské Lázne.
Celebrated natural spring waters combined with stunning neo-classical architecture attract many visitors to Mariánské Lázne. However, the high failure rate and poor reliability of the 100-year-old sewerage system in this Czech spa town posed a threat not only to health but consequently to the town’s reputation as a resort.
Wastewater leakage meant harmful substances were at risk of penetrating the catchment of Mariánské Lázne’s curative springs. From the outset, officials wanted to maximise protection of the sensitive environment, minimise the risk of groundwater contamination and avoid disruption to both spa and town.
Commencing at the end of 2001, the works proceeded under full operation of the sewerage system and without disruption to the spa season. This was achieved by the use of trenchless technologies in 80% of the rehabilitation work.
Contractor Brochier carried out reconstruction of 11.5km of sewer pipeline as follows:
l hose re-lining in least risk-bearing locations: 5.7 km
l re-lining with retraction of hard pipes into existing sewers in greater environmental risk-bearing zones: 1km
l berstlining in partially covered sewers: 0.8 km
l Mason´s method: 2.1 km
l open excavation technologies: 1.9 km
The project was jointly financed: 60% by the European Union (EU) Phare CBC Programme (¬2.6 million) and the remainder by manager and operator Chevak Cheb (¬1.7 million). The international tender, floated in accordance with EU regulations, was won by Czech building company Stavby Silnic a Zeleznic.
Special measures were needed to protect the groundwater from contamination by leakage of chemicals during rehabilitation. Closely observed by the media, government institutions and the EU, supervision was undertaken by the Health Resort Inspectorate of the Czech Ministry of Health.
A detailed hydrogeological and environmental monitoring system was developed and used by Geonika as an obligatory part of the works.
Confirming that the project’s environmental targets had been met, Health Minister Marie Souková confidently stated: “Thanks to the capability and professionalism of the contractor and sub-contractors, no negative impact on the quality of the valuable natural resources has occurred.”
Despite being undertaken during the biggest rainfalls and floods in a century, the works were completed by autumn 2003. Reconstruction has had a remarkable impact on the environment of Mariánské Lázne, and the project leaders were presented with the No-Dig Award at No-Dig 2004 in Hamburg.
Hydrogeological monitoring six months after completion confirmed that no harm had been caused to the natural resources or the environment.
The positive results of the Mariánské Lázne experience will soon be utilized in similar projects in other Czech spas. Projects in Karlovy Vary (Karlsbad) and Teplice are still in the planning stage and applications are being filed with the EU.
Implementation is expected in 2005 for Karlovy Vary and 2006-7 for Teplice. As yet, it is not known who will win the tender for these large, complex projects.
Trenchless reconstruction works in sewers under Mariánské Lázne
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