ROTEC is developing two main technologies to address this problem:
Scaling prevention is achieved by applying Flow Reversal (FR) technology in Reverse Osmosis (RO) desalination systems. FR is a Smart innovative and proprietary process for scale prevention on membranes surfaces, which works by periodically switching the flow direction in RO pressure vessel arrays. The frequency of switching is dictated by the time it takes for a supersaturated solution in the concentrate to grow a population of scale particles that can allow continued scale growth (denoted the "Induction Time"). By using the effectively under-saturated feed to sweep away the beginning scale particles in the concentrate before they exceed a critical size, extensive precipitation is prevented. This approach affords operating at much higher recoveries than what can be achieved with anti-scalants alone. Applying FR allow the operation of desalination plants at high recovery levels without the hazard of scaling. The technology is applicable to RO base desalination plants via Retrofit of existing desalination plants or grassroots design of new plants.
The scientific basis for the Flow Reversal technology was developed at the Ben-Gurion University, Israel by Dr. Jack Gilron and Professor Eli Korin. ROTEC holds several granted/approved and pending patent applications to protect its Flow Reversal technology.
Sensing the commencement of local mineral scaling on surfaces is achieved by applying ultrasonic technique. The technique is based on the change in the shape and arrival time of ultrasonic waves reflected from the surface being monitored. When the surface is scaled, the arrival time and shape of the reflected wave is changed. Therefore the ultrasonic sensor acts as a null sensor and allows use of existing surfaces as the baseline for detecting changes. This makes the sensor quite sensitive to the initiation of scaling processes. Special algorithms have been developed that allow sensing this change in real time. One of the inherent advantages of ultrasonic sensors is that they are non-invasive. They are therefore ideal for identifying potential scaling problems and for providing in-situ real time warning of incipient scaling on surfaces in water treatment and process equipment such as pipelines, membrane modules, heat exchangers and cooling towers.
The scientific basis for the Ultra-Sonic based Scale Sensor technology was developed at the Colorado-Bolder University, USA. ROTEC signed an exclusive and irrevocable license agreement with the University, regarding their membrane scaling ultrasonic detection technology.