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Swiss to use Ozone to clean Waters
SPECIAL REPORTS - CLEAN WATER
Swiss to use Ozone to clean Waters
Pilotversuch fĂĽr noch saubereres Wasser
Source: www.swissinfo.org
August 2007
A pilot study is set to combat a new enemy of Switzerland’s lakes and rivers: micro-contamination.
Der Zustand von Seen und Flüssen in der Schweiz ist nach einer Periode ständiger Verbesserung stabil. Heute gibt es eine neue Herausforderung für sie: die Mikroverunreinigungen.
While water quality has improved progressively over the past three decades, the situation has stabilised. The Federal Environment Office, which is behind the initiative, will now use ozone to purify Swiss waters.
Micro-contamination is caused by minute traces of so-called organic elements such as herbicides, cleaning materials and medicines.
These are to be found in very low concentrations in water, from a billionth (nanogram) to a millionth (microgram) of a gram per litre.
A nanogram of contamination is the equivalent of a headache pill dissolved in a 25-metre long swimming pool, according to the Federal Environment Office.
The pilot project - at Regensdorf near Zurich - seeks to minimise micro-contamination passing from water used in residential areas into lakes and rivers.
A special technique involving ozone will be administered in addition to other purification methods, Alberto Bianchi, head of the water protection agency in canton Ticino, told swissinfo.
Liquid oxygen or O2 is converted into ozone or O3. “This is then added to sewage water, which enables the removal of micro-contaminants,” Bianchi explained.
Challenges
Current sewage plants are geared towards eliminating nitrates and phosphates, which cause rapid growth in algae and water plants, which in turn use up oxygen reserves in the water.
These plants are unable to eliminate micro-contaminants completely.
However, combating micro-contamination is not only a technical problem. Sometimes, certain substances are found in surprisingly high concentrations. This is true of medicines, which are often used unnecessarily.
“The real challenge lies in consuming such products sensibly,” stressed Bianchi. “Medicine should only be taken if it is absolutely necessary.”
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Swissinfo: SRG SSR idée suisse
Source: http://www.swissinfo.org/eng/swissinfo.html?siteSect=105&sid=8052930
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