The eductor system (also known as the ejector system) is specialist technique used to control pore water pressure in low permeability soils such as very silty sands, silts, or clays with permeable fabric. Eductors are typically used to help stabilise the side slopes and base of excavations in soils that would be difficult to dewater with wellpoints or deep wells.
Eductors have the advantage that they can allow vacuum-assisted drainage, to draw water out of poorly draining fine-grained soils. The system works by circulating high pressure water (from a tank and supply pumps at ground level) down the well to a small-diameter nozzle and venturi located in the eductor in each well. This generates a vacuum of up to 9.5 m of water at the level of the eductor. The vacuum draws groundwater into the well from where it is piped back to ground level via a return riser pipe and thence through the reservoir tank back to the supply pump for recirculation.
Groundwater Engineering provides complete eductor dewatering solutions:
- Design of dewatering systems
- Well drilling and installation
- Equipment sales and rental
- Monitoring systems
- On-site operation and maintenance