The FEDI (fractional electrodionization) technology produces high purity water and, according to QUA, is an improvement on EDI for the production of high purity water for power and semiconductor applications. Unlike conventional EDI, FEDI stacks are able to tolerate hardness in the feed water and as a result, FEDI can be used after single pass reverse osmosis (RO) without the need for softening, or second pass RO, on most feed waters.
Each FEDI stack is equipped with two sets of electrodes. Hardness and the majority of the other ions are removed in the bottom of the stack at low current density and low scaling conditions, while the final product water polishing takes place in the top of the stack at high current density.
The Q-SEP hollow fibre ultrafiltration modules contain ultrafiltration membranes manufactured with QUA’s Cloud Point Precipitation method which helps ensure a high pore density along the length of the fibre and uniform pore size distribution in the membrane. QUA says that Q-SEP modules can deliver improved product water quality when compared to conventional ultrafiltration modules, with low silt density index (SDI) and improved rejection of bacteria and viruses.
The modules are made from a hydrophilic polyether sulphone (PES) material that provides high fibre strength and improved low fouling characteristics. The membranes operate under low trans-membrane pressure in an inside-out flow configuration. The Q-SEP is suitable for the pre-treatment of RO systems (brackish and seawater applications), the purification of surface and well water for potable applications, the filtration of industrial water, and wastewater recycling and reuse.
