Bubble curtain minimises intrusion during dredging activities

In October, the site preparation entered a new phase when dredging company Dosco Baggerwerken arrived at site. Their mission is to increase the water depth from 2.5m to 4m. In total, around 15.000m³ of contaminated sediment will be removed from the harbour. Dosco Baggerwerken, having a vast experience in this underwater activity, mounted a crane gathering bottom sediments onto a barge. The sediment will then be loaded on a vessel disposing of it at a different location.

To avoid that the dredging process carries away spoils from the dredged area, Dosco Baggerwerken installed a bubble curtain at the bottom of the harbour. Atlas Copco devoted considerable effort to study the air bubble technique. By forcing 100% oil-free compressed air through a submerged perforated hose, a series of "bubble plumes" arise from the holes.The rising bubbles cause a vertical current of air and water flowing towards the surface. This in turn generates an air curtain keeping the spoiled water separated from the rest of the harbour. As a result, the intrusion of contaminated water is kept to a minimum and also allows boat traffic to pass.

For the creation of the bubble curtain, Atlas Copco Rental installed an electric driven oil-free air compressor. The advantages this energy efficient solution bring are the fast start-up and low noise during operation, which was much appreciated by the customer. The installation runs on a single shift operation but in case they need technical support, the Atlas Copco Rental technicians are stand-by 24/7.

• Sarah Geerts, Divisional Communication Manager Atlas Copco Specialty Rental Email: sarah.geerts@atlascopco.com

Atlas Copco is a world-leading provider of sustainable productivity solutions. The Group serves customers with innovative compressors, vacuum solutions and air treatment systems, construction and mining equipment, power tools and assembly systems. Atlas Copco develops products and service focused on productivity, energy efficiency, safety and ergonomics. The company was founded in 1873, is based in Stockholm, Sweden, and has a global reach spanning more than 180 countries. In 2015, Atlas Copco had revenues of BSEK 102 (BEUR 11) and more than 43 000 employees.

Specialty Rental is a division within Atlas Copco’s Construction Technique business area. It serves customers in the industry segments around the world with temporary air, nitrogen, steam and power rental solutions. The specialty rental services are offered under several brands. The divisional headquarters is located in Houston, USA.