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| Vertical dewatering |
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Gravity filter system
 Gravity filters are filters in which the water flows into the filters only by gravitation. With the use of drilling rigs, equipped with flushing tools or hollow auger drills, 9-10 metres long filters can be installed vertically or at an angle.The filter consists of a PVC drain protected by a coconut fibre. In this drain a PVC tube is installed, which is connected above ground to the conduit-pipes of the vacuum pump. Vacuum filter Vacuum filters are PVC tubes with a length of 4-7 metres with a slotted section. They can be flushed in by hand or by means of a flush-boring with the use of a drilling rig. Above ground the filters are connected to a conduit pipe which is connected to a vacuum pump. In this way a vacuum will be created around the filters to stimulate the flow of the groundwater towards the filters. This system is mainly used in fine, sandy soils. Use of water tanks Here filters are installed by hand, using flushing tools and water from the tank truck. The filters are connected to the conduit pipes |