Demineralisation plant

The bespoke engineered plant was designed to treat a blend of borehole and towns mains water. It consists of two streams, each capable of producing up to 8m3/h of high purity demineralised water, which can operate as duty/standby.

Each stream has duplex softeners and a MegaRO reverse osmosis unit followed by CEDI-VNX continuous electrodeionisation and final non-regenerable mixed bed polishers charged with nuclear grade resin to meet the treated water specification of conductivity <0.1µS/cm, silica <5µg/kg and dissolved organic carbon (DOC) <0.1µg/kg. A mobile rig allows in situ cleaning of the RO membranes.

The plant is skid mounted to the highest possible degree and factory tested to reduce site installation time, and is fully compliant with Hitachi’s specifications. It is controlled by a motor control centre with a process control section using a Siemens S7-300 programmable logic controller which interfaces, via a Profibus DP communication link, with the site DCS.