Advanced regeneration system for cleaning water wells

Oct 19 2009

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.

Prolonging a well's life

The five partners of project WELL REGENERATION pooled their expertise to develop an advanced well regeneration system that would prove more cost effective, energy efficient and eco-friendly than existing methods. Their goal was to find a way of combining mechanical and ultrasound methods that used the lowest possible amount of energy, reduced the amount of chemicals needed by half and doubled the length of a well's regeneration cycle.

The innovative aspects of the project included the development of software to determine the optimal length of a regeneration cycle, and new flow technology to improve the passage of water through gravel beds to facilitate removal of deposits. Cameras were also developed to supervise the cleaning process, to make sure all procedures work efficiently and to check that the inside of a well pipe is smooth and free from sediment and deposits. For a well to perform at its best it's especially important that the tips of its suction pipes as well as the gravel bed are deposit-free, so that water can flow through freely.

Different prototype systems were tested to determine the most advantageous combination of mechanical and ultrasound cleaning techniques in terms of minimising the amount of chemicals and energy required. By the end of the 28-month project the team had successfully met all their objectives, says Vassmer. "The system we came up with completely removes all soft and hard deposits that normally start building up in a well before they become a problem and deep cleans the gravel bed. The entire process is monitored by CCTV camera, to ensure the well is thoroughly cleaned."

Collaboration the key to success

The complementary capabilities and resources of WELL REGENERATION's partners, as well as their excellent teamwork, were key factors in the project's successful outcome. "EUREKA's assistance was invaluable in helping to build the network and sustain collaboration and momentum among the partners, and the organisation also helped us to secure funding at a national level," adds Vassmer.

Each partner brought their individual know-how to bear on finding solutions to the project's many complex challenges. BPS-Celle was responsible for developing the mechanical cleaning system, while the Moscow-based Centre of Applied Acoustics focused on the high performance ultrasonic cleaning tool. Two other partners, geo-technology and environmental management specialists Ingenieurgesellschaft Fur Feotechnik Und Umweltmanagement and Lueneburg University's faculty of construction engineering, collaborated on developing the innovative flow technology and software, as well as the camera monitoring system supervising the cleaning process. The laboratory resources and expertise of Hungarian company Euro-Open Kft laboratory were invaluable in conducting all measurements and practical trials of the prototypes, and in evaluating and validating the results.

Keen to exploit their findings, the partners are in the process of preparing a new project to improve and refine the WELL REGENERATION process further, focusing in particular on the mechanical processes. Meanwhile the technology is now in commercial use by water companies all over Europe.