In Anuradhapura, Sri Lanka, groundwater exceeds hardness and fluoride limits (fluoride concentration 3.29 mg/L, 3.29 times over standard), identified by WHO as a primary cause of chronic kidney disease. The skid-mounted targeted electrodialysis unit (TED) developed by Chinese Academy of Sciences processes 300 tons of groundwater daily through selective ion migration technology. This electrodialysis unit integrates electrode water acid dosing and shutdown polarity reversal functions, requiring only sand filtration pretreatment. Its single-button operation interface suits technically underdeveloped areas. Post-treatment results show 98% calcium/magnesium removal rate, fluoride concentration below 0.27 mg/L (meeting drinking standards), with energy consumption of 1.5 kWh per ton, providing stable water supply for 1,500 people.
Take a look at what other precious metal materials are available in the water treatment industry.
Coal chemical and cement industries incorporate electrodialysis units into zero-discharge process chains. Some cement plants use homogeneous membrane electrodialysis units for secondary concentration, elevating concentrated water conductivity to 147.7 mS/cm with 14.6× concentration ratio, enabling water reuse in circulation systems. When processing high-hardness RO concentrate using four parallel electrodialysis units, scaling and electrode sparking occurred. Modifications included installing online hardness monitors for real-time alerts, replacing with titanium alloy electrodes, and integrating automatic polarity reversal. After optimization, electrodialysis units achieved 1,200-hour continuous operation cycles with 40% reduction in water treatment costs.
Long-term stability relies on scaling prevention and current distribution optimization. A case from Nantong electronics factory (China) showed membrane surface magnesium hydroxide deposition causing resistance spikes when inlet hardness exceeded 1.5 mg/L. By installing dual-stage softening resin tanks and implementing 7% citric acid cyclic cleaning, membrane stack lifespan extended to 5 years.
Lonics power plant (Germany) improved current uniformity through water distribution groove redesign: installing flow-dividing grids in electrodialysis unit collection tanks reduced flow deviation from 15% to 3%; 0.4 mm polyethylene distributors balanced water flow to prevent membrane cracking. With bi-monthly low-pressure flushing, membrane resistance remained below 10 Ω·cm². For acid whey treatment, Lactalis (Canada) adopted pulsed electric field mode (PEF 5s/5s), increasing calcium removal by 35.1% versus continuous current mode while significantly reducing hygroscopicity in spray-dried powder.
Global electrodialysis unit sales reached $386 million in 2024, projected to grow to $889 million by 2031 at 8.3% CAGR. Technological iterations and operational experience accumulation are expanding applications from water treatment to lithium extraction and food industry sectors.
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