Environment Water and WastewaterCapacitive Deionisation System
A single RDI™ cylinder is designed to remove all or most of the salt. Because of minimal pressure drop, multiple cylinders can be operated in series and at high flow rates, enabling processing of high total dissolved solids (TDS) streams without the need for intermediate storage. Each device removes a portion of ions from the stream until the target dissolved solids level is reached.
Radial deionization – RDI™ – is a proprietary form of capacitive deionization (CDI). In radial deionization, an aqueous stream containing salt is passed between two oppositely charged supercapacitors. As the liquid passes through the dielectric spacer separating the capacitors, ions are attracted to the oppositely-charged capacitor layers. The ions leave the water within the dielectric layer, pass through a charge specific membrane coating, and are adsorbed onto the surface area of the carbon supercapacitor.When the capacitors have filled with ions, the polarity is reversed and the ions are discharged back into the dielectric spacer and removed from the system. A 3-way valve is situated at the outlet of the device(s), directing brine away from the cleaned water.With Atlantis’s patented radial deionization technology, RDI™, each pair of super capacitors forms a “cell”. Up to 100 cells are layered together to form the RDI™ cylinder. The wastewater stream flows through the dielectric spacers within the cylinder with a minimal pressure drop.A module consists of one or more RDI™ cylinders, associated valving, DC power supplies, and controls. A system will typically contain one or more modules depending on purification level and flow rate required. A typical module layout is shown below. The 4 ft by 14 ft skid contains 20 cylinders and is designed to fit in a semi or flatbed. A module can process up to 100 gpm depending on the incoming salinity level.The cycle time of the device ranges between 2 – 20 minutes for cleaning and 2 – 20 minutes for purging. Many applications require the use of more than one cylinder to allow constant flow to be maintained.