The old wastewater treatment plant in Prague-Bubenec
The old wastewater treatment plant in Prague-Bubeneč is an important witness to the history of architecture, technology and water management. Built in 1901-1906, it was used for the treatment of most of the sewage water in the city of Prague until 1967. In the steam engine room one can view the still functioning machines from the early 20th century. The design of the sewer system with the proposed technical parameters of the treatment plant was prepared by a construction engineer of British origin, Sir William Heerlein Lindley. In 2010 his work was declared a cultural monument. Old plant is one of the most important industrial heritage sites in Europe.
The well preserved building of the old wastewater treatment plant in Bubeneč is the oldest preserved facility of its kind in Europe, a unique industrial architecture, a unique Eco monument of world importance, which is interesting both from architectural and technological points of view. Already in 1884, the competition was announced for the project of a new sewerage system and wastewater treatment plant, several projects were drafted but only the project of the famous English engineer William Henry Lindley was implemented – he had a lot of practical experiences from other big European cities and used some positive elements of previous projects of Czech designers in his project. His system of Prague sewerage network used catchment ratios so that sewage pumping was not necessary. The sewerage network discharged in the new wastewater treatment plant in Bubeneč. At that time Prague’s sewerage system measured about 90 km. The area of the wastewater treatment plant by Lindley project was built in 1900 – 1906 as a part of the new Prague sewerage system that was designed for 700 000 inhabitants. The sedimentation treatment plant in Bubeneč was the first major water treatment building in Bohemia.
It consists of a main operation building with two chimneys, a smoke chimney and a ventilation chimney. Under the ground there is the six feet deep sand trap, ten underground septic tanks, two wells and sewage sludge pump shafts. The sludge from the sedimentation tank was pumped to two sludge tanks on the Emperor’s Island or to ships and those transported it to other sludge tanks, from where they were sold (after drying) as a highly demanded fertilizer. The railway branch led to the sludge tanks on the Emperor’s Island. Then three-stage cleaning efficiency was about 40%. The capacity of the wastewater plant started not to be sufficient from the 1920s and consequently only an extension was built before the World War II. A brand new wastewater treatment plant was built much later, namely in 1967. Today’s sewerage system is about 2,400 km long, whereas a part of sewage conduits is man-sized, i.e. greater than 80 cm; other sewage conduits are lower, i.e. less than man-sized. It has about 55,000 manholes and only 19 pumping stations. Today’s wastewater treatment plants reach the efficiency of 90 to 95%. The original wastewater treatment plant area was still in good condition, and so it has been maintained next to the new one. Thus it was possible to establish a foundation in 1992, the mission of which was to operate the Eco-museum in this precious building.
Visitors to the museum come through the inlet crypt, where the water wheel driven by the incoming sludge used to be fitted and consequently the sludge come into the largest underground construction – into a sand trap, where three main municipal sewers discharged. From there they pass to the discharge sluices and mechanical rack catchers and then go down to ten sedimentation tanks, where the primary sludge used as a fertilizer settled. The highlight of the tour is two-storey engine room with two reconstructed steam engines installed in 1904, both still functional, below which there are flood pumps. Also the steam boiler room with the two coal boilers is still functional.