Wells are used to extract water from aquifers, natural underground stores of water found on layers of permeable rock, gravel or clay. The water is pumped up and transported via pipes to treatment works, where it is cleaned and filtered through gravel beds before being conveyed to domestic and business consumers via a network of smaller pipes or mains. “In large areas of Germany, hygienically acceptable groundwater deposits can be found at depths of 100-400 metres,” says Dr Andreas Vassmer of Brunnen-Und Pumpenservice Celle (BPS-Celle) GmbH, well regeneration specialists and lead partner of EUREKA project E! 3920 WELL REGENERATION. “Making these deposits available as good quality drinking water is relatively easy and economically feasible, especially for small and medium sized water suppliers.” However, depending on the geological characteristics of its location, a well needs to be ‘regenerated’ annually using mechanical, chemical and ultrasound methods of cleaning. After a time the well starts to age and overall performance gradually deteriorates. Pipes erode and may become blocked from an accumulation of mud and deposits composed of aluminium, carbonates, iron and manganese. Many wells in countries with a central European climate and geology suffer from this kind of aging, which is caused by chemical or bacterial oxidisation and accelerated by bacteria in the soil. If the mud becomes hard, removing the solidified deposits becomes increasingly difficult; a well eventually becomes economically unviable and a new one must be built at an average cost of €50,000.
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