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A new spin on ultrasonic algae control in wastewater-treatment applications

| By Mary Page Bailey

Ultrasound treatment is a non-chemical method to control algae using specific sound frequencies emitted through water to cause internal damage to polluting algae cells. Most previous work in the area of ultrasonic algae control has focused on very loud emitted frequencies to create cavitation bubbles that damage the algae cells, but a new line of products from Sonic Solutions Algae Control LLC (Northampton, Mass.; and WaterIQ Technologies (Wilson, Wyo.; emits over 2,000 different frequencies on two bandwidths to take advantage of critical structural resonance (CSR)‚ the specific frequency that ruptures the vesicles within algae cell walls. The damaged algae cells lose their buoyancy or have torn inner cell walls, causing them to naturally decompose due to lack of sunlight or damaged functions. Launched in October at Weftec, The Pulsar 4000 and 3000 models are said to be the only devices on the market to provide 360-deg, CSR-based ultrasonic coverage in ponds, reservoirs and clarifier tanks.

“When you emit frequencies at an object’s CSR, the object begins to vibrate, and if the frequency is strong enough, the object can damage itself with shearing vibration,” explains George Hutchinson, chief technology officer and vice president of operations at Sonic Solutions Algae Control. A benefit of CSR-based control over cavitation is lower power consumption and longer distance coverage. “To use cavitation to damage algae several hundred meters away, the device has to create almost an explosive surge to create cavitation at that distance. Our devices stay well below the cavitation threshold,” says Hutchinson.

Furthermore, the wide range of frequencies emitted by the devices enable them to mitigate over 90% of different algae species encountered in wastewater treatment plants, agricultural farms and more. The key to tapping into so many frequencies is a specially designed piezo transducer head and microprocessor.