Bubeneč and Císařský Island have been unique locations in the history of wastewater treatment since the end of the 19th century. Visitors here have an exceptional opportunity to explore the Old Wastewater Treatment Plant (www.staracistirna.cz), built in 1906 as the final link in Prague’s combined sewer network, which is an important monument to the history of architecture, technology and water management. The plant was in operation until 1967, when its job was taken over by the Central Wastewater Treatment Plant.
In the early ‘90s it became clear that the Central Wastewater Treatment Plant wouldn’t have sufficient capacity for Prague’s future development and to meet ever higher demands on treated effluent quality. Severe flooding in 2002 then sped up the search for the right location. Before that, the New Water Line’s site had been allotment gardens and tennis courts, but this deluge damaged the land so badly that it couldn’t be used for gardening and would have taken years to restore.
By adding the New Water Line, we advanced the plant’s technology into the 21st century. Its workings are concealed from the eyes of visitors inside a huge reinforced concrete shell. After three years of construction, followed by trial operation, the New Water Line went into permanent operation at the end of 2021. The four stops of this tour will, at least virtually, guide you through the hidden core of this construction, which is so important both for Prague and the environment.
Construction of the New Water Line began on 9 October 2015, and it was completed and handed over for trial operation three years later. The main reinforced concrete work took two years, with one more for the mechanical and electrical part. This was an impressive feat for such a vast and complex task, and indeed there were times when up to 700 people from all professions were working on the construction together. It’s worth noting that the construction itself was preceded by a demanding preparation period of over ten years. The total cost came to almost 6.5 billion Czech crowns.
So when this new part of the plant was designed, it obviously had to withstand any further floods. It was therefore made watertight, and floodwaters can flow right over it, protecting the technological equipment inside and allowing operation to be quickly resumed as quickly as possible. The site is also raised above the surrounding terrain, and its walls are protected by a heavy crushed stone embankment.
When deciding on the size of the New Water Line site, a major role was played by a nearly 200-year-old veteran oak tree that set a limit for its eastern boundary. This new section of the plant covers a respectable 6.5 hectares, and is run by just 45 employees divided into three shifts. Much of the site is publicly accessible as it has been landscaped into a park with paths built round it, offering a place for the people of Prague to walk with a 360° panoramic view of the Vltava valley. The outflow channel for cleaned water resembles a mountain stream, with its slope and the bubbling sound of its water, and its outfall into the Vltava river is a popular spot for fishing because of the many fish it attracts.
… that all the tanks are made of waterproof concrete?
This means we didn’t need to use water insulation or other materials to ensure they are watertight.
If you want to know more, continue to other parts of the treatment plant ...