Advanced Induction Time Antiscalant Testing for Dynamic Recovery RO Systems Improves System Performance and Reduces Waste

Salt Concentrations TRO vs Dynamic RO Traditional RO (TRO) systems: “steady state” when it comes to the concentration of salts in solution This leads to membranes seeing the same level of saturation throughout operation Dynamic Processes: batch process that varies the salt concentration as a function of time This leads to variable saturations and salt concentrations throughout system operation Ref 5: Kucera Synthetic calcium sulfate and barium sulfate water used in laboratory to test various antiscalants Samples inspected every hour for visible precipitation, turbidity changes and micro-scaling Proprietary “concentrator tool” used to validate results Test individual Formulate high Confirm and validate products with each CaSO4 and BaSO4 induction time with CaSO4 and BaSO4 saturations in lab “concentrator tool” saturation Validation- Concentrator Tool Synthetic CaSO4 solution was fed into the concentrator tool and concentrated to 85% recovery with RO membrane where CaSO4 saturation was increased to 7.0x saturation A control was run with no antiscalant Product 2 was added into the feed at 4.5 ppm (30.2 ppm in the brine) and concentrated to 85% recovery The brine concentrator was put in “closed circuit” mode and solution circulated for 5 hours Samples of the brine we collected to test calcium, turbidity, sulfate and visual inspection The membrane was then analyzed using Chromatic Elemental imaging for Scale Results Membrane and NTU vial Product Parameter Blank Product Feed Turbidity 0.19 0.20 (NTU) Feed Temp 26.2 26.1 (C) Feed pH 7.20 7. Brine Turbidity 234 0.19 (NTU) Brine Temp 26.8 26.7 (C) Brine pH 7.67 7. Membrane and NTU vial Brine SO4 3550 9009 Control (ppm) Brine Ca 1176 3907 (ppm) You’re Only as Good as Your Induction Time Brine tanks increase induction time Long brine increase induction time Small water changes can make big problems at high recovery pH, temperature Water analysis quality Seasonal changes in water quality Make sure to get to a dilution source immediately 1 hour lab induction times, don’t always correlate to a well running system Dynamic processes can take longer than an hour in some cases Hydraulic design changes Seed crystals will increase the rate of precipitation to a point of no return Scale will start to form inside Membrane surface Break tanks or other types of holding tank Brine disposal piping Brine lines scaled with CaCO 3 Induction time measurements in two brackish water reverse osmosis plants for calcium carbonate precipitation.