A two-year study at the University of Pittsburgh has found that non-chemical water treatment devices thought to be environmentally preferable to chemicals like chlorine in large water-cooled buildings do not prevent the growth of dangerous bacteria as the water warms and is returned to the cooling tower.
Janet Stout, director of the Special Pathogens Laboratory and an expert on Legionnaire’s Disease, says researchers tested five different systems, including electromagnetic, electrostatic, ultrasonic, hydrodynamic cavitation and magnetic devices. (The latter are only intended to prevent mineral buildup.)
Stout says architects and engineers may specify the non-chemical treatment devices to earn environmental ratings such as LEED certification without following up to see if the system actually works effectively.
She recommends that buildings using only non-chemical devices test their water for bacteria to avoid public health dangers like Legionnaire’s Disease.