After visiting the Moravian metropolises, we return to the Czech Republic, this time to Pilsen, a city with more than 170,000 inhabitants. Drinking water consumption in the West Bohemian metropolis has fallen from more than 110 litres per person per day to 90 litres in 10 years since 2009. This is mainly due to the increasing use of water-saving appliances and water savers in households. However, in 2019 the reduction in consumption has stopped.(1)
The beginnings of the mass supply of drinking water to Plzeň date back to the 16th century. Through the still standing water tower (the so-called Black Tower), a total of 4 fountains on the Republic Square were supplied with water from the Radbuza River for almost 300 years. In 1889, Dr. Škoda's company built a new waterworks complex. It included a water treatment plant under Homolka Hill, which already drew water from the Úhlava.(2)
source: visitplzen.eu
This river is a source of drinking water not only for Pilsen, but also for Klatovy and Domažlice. The Nýrsko reservoir, created in 1969 by flooding the Úhlavský valley in the Šumava Protected Landscape Area, serves to accumulate water.(3) Of all the reservoirs in the Berounka river basin, this one has the cleanest water and is very easy to treat into drinking water.(4)
However, due to the industrial boom at the beginning of the 20th century, the quality of water in the Úhlava River declined significantly. Due to the lack of funds and the high demands of society, the so-called drinking water system was built in 1916. This distributed drinking water from the wells of the Rouden brewery to 120 standpipes and 25 schools and other public buildings. Until 1970, when a new chemical treatment plant was built, two water supply systems operated side by side: drinking water from the brewery and drinking water from the old waterworks under Homolka.(2)
Recently, Pilsen has had to cope with high levels of certain pesticides (mainly those used in the cultivation of biofuels such as corn or oilseed rape) found in its drinking water. For five substances, sanitary exemptions and increases in the permissible limits were even granted(5).
More frequent controls on the use of pesticides in agriculture in the Úhlava catchment area and the partial replacement of sand filters with granular activated carbon filters were not sufficient and in the long term there was a risk of a significant deterioration in the quality of drinking water.(5) Therefore, the waterworks underwent modernisation between 2013 and 2016.(6) This was mainly focused on the addition of technology for the removal of pesticide substances. This method of water treatment has proved its worth, and the drinking water now meets the strict parameters of the Ministry of Health and the EU. The modernisation of the ÚV at Homolka has thus contributed to the reduction of health risks for the inhabitants of Plzeň.(7)
source: plzen.eu
Primary sewers were built in Pilsen as early as the 17th century, but they were only haphazard constructions with free outlets. At the end of the 19th century, a proposal for a flushing unified sewerage system was implemented, which was gradually expanded as the city grew. Today, 98% of Pilsen's population and all of its industry are connected to this system.(8)
Although there were efforts to introduce wastewater treatment as early as in the 1920s, the first wastewater treatment plant in Pilsen was not put into operation until 1964 after ten years of construction accompanied by numerous problems. At that time, the water quality in the Berounka River was already in a catastrophic state due to industrial development(9).
source: Vodárna Plzeň
The operation of this treatment plant (WWTP I) was curtailed after 1997, when a new, more modern treatment plant (WWTP II) was built on the left bank of the Mže. When the WWTP I site was devastated by floods in 2002, its operation was completely shut down. WWTP II was intensified between 2010 and 2012, mainly to increase nitrogen removal efficiency(9).
Resources:
- (1) https://www.vodarna.cz/od-1-5-2020-se-zlevnuje-vodne-a-stocne/
- (2) https://www.vodarna.cz/uprava-pitne-vody/
- (3) https://www.kudyznudy.cz/aktivity/vodni-nadrz-nyrsko
- (4) https://ukr.plzen.eu/cz/zivotni-prostredi/revitalizace-nabrezi-plzenskych-rek/uhlava/uhlava.aspx
- (5) https://www.ceskatelevize.cz/porady/1095913550-nedej-se/212562248420031-kvalita-pitne-vody-v-plzni
- (6) https://www.vodarna.cz/vyjadreni-spolecnosti-vodarna-plzen-k-problematice-pesticidu/
- (7) https://plzensky.denik.cz/zpravy_region/plzenane-uz-mohou-pit-nezavadnou-vodu-bez-pesticidu-a-zbytku-leku-20160415.html
- (8) https://www.vodarna.cz/plzenska-kanalizace/